Added locale detection & reduced apk size by 5mb

.gitignore

@@ -14,4 +14,5 @@
 .cxx
 local.properties
 /app/elixir-app
-/app/src/main/assets/app.zip
+/app/src/main/assets/app.zip
+/app/src/main/assets/app.zip.xz

app/build.gradle

@@ -36,7 +36,8 @@ android {
 
     buildTypes {
         release {
-            minifyEnabled false
+            minifyEnabled true
+            shrinkResources true
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
     }
@@ -63,7 +64,6 @@ dependencies {
 
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     implementation 'androidx.core:core-ktx:1.5.0'
-    implementation 'androidx.appcompat:appcompat:1.3.0'
     implementation 'com.google.android.material:material:1.3.0'
     implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
     testImplementation 'junit:junit:4.+'

app/src/main/java/io/elixirdesktop/example/Bridge.kt

@@ -7,16 +7,19 @@ import android.util.Log
 import android.webkit.WebSettings
 import android.webkit.WebView
 import org.json.JSONArray
+import org.tukaani.xz.XZInputStream
 import java.net.ServerSocket
 import java.net.Socket
 import kotlin.concurrent.thread
 import java.io.*
+import java.util.*
 import java.util.zip.ZipInputStream
 
 
 class Bridge(private val applicationContext : Context, private var webview : WebView) {
     private val server = ServerSocket(0)
     private var lastURL = String()
+    private val assets = applicationContext.assets.list("")
 
     init {
         Os.setenv("BRIDGE_PORT", server.localPort.toString(), false);
@@ -54,7 +57,7 @@ class Bridge(private val applicationContext : Context, private var webview : Web
             throw Exception("Could not find any supported ABI")
         }
 
-        val runtime = "$prefix-runtime.zip"
+        val runtime = "$prefix-runtime"
         Log.d("RUNTIME", runtime)
 
         thread(start = true) {
@@ -64,46 +67,43 @@ class Bridge(private val applicationContext : Context, private var webview : Web
             val nativeDir = packageInfo.applicationInfo.nativeLibraryDir
             val lastUpdateTime: Long = packageInfo.lastUpdateTime / 1000
 
-            val releasedir = applicationContext.filesDir.absolutePath + "/build-${lastUpdateTime}"
-            var bindir = "$releasedir/bin"
-            Os.setenv("BINDIR", bindir, false);
+            val releaseDir = applicationContext.filesDir.absolutePath + "/build-${lastUpdateTime}"
+            var binDir = "$releaseDir/bin"
+
+            Os.setenv("BINDIR", binDir, false);
             Os.setenv("LIBERLANG", "$nativeDir/liberlang.so", false);
-            val donefile = File("$releasedir/done")
+            val doneFile = File("$releaseDir/done")
 
 
-            if (!donefile.exists()) {
+            if (!doneFile.exists()) {
 
                 // Creating symlinks for binaries
                 // https://github.com/JeromeDeBretagne/erlanglauncher/issues/2
-                File(bindir).mkdirs()
+                File(binDir).mkdirs()
                 for (file in File(nativeDir).list()) {
                     if (file.startsWith("lib__")) {
                         var name = File(file).name
                         name = name.substring(5, name.length - 3)
-                        Log.d("BIN", "$nativeDir/$file -> $bindir/$name")
-                        Os.symlink("$nativeDir/$file", "$bindir/$name")
+                        Log.d("BIN", "$nativeDir/$file -> $binDir/$name")
+                        Os.symlink("$nativeDir/$file", "$binDir/$name")
                     }
                 }
 
-                if (unpackZip(releasedir, applicationContext.assets.open("app.zip")) &&
-                        unpackZip(releasedir, applicationContext.assets.open(runtime))) {
-                    val assets = applicationContext.assets.list("")
-
-                    for (lib in File("$releasedir/lib").list()) {
+                if (unpackAsset(releaseDir, "app") &&
+                        unpackAsset(releaseDir, runtime)) {
+                    for (lib in File("$releaseDir/lib").list()) {
                         val parts = lib.split("-")
                         val name = parts[0]
 
-                        val nif = "$prefix-nif-$name.zip"
-                        if (assets!!.contains(nif)) {
-                            unpackZip("$releasedir/lib/$lib/priv", applicationContext.assets.open(nif))
-                        }
+                        val nif = "$prefix-nif-$name"
+                        unpackAsset("$releaseDir/lib/$lib/priv", nif)
                     }
 
-                    donefile.writeText("$lastUpdateTime")
+                    doneFile.writeText("$lastUpdateTime")
                 }
             }
 
-            if (!donefile.exists()) {
+            if (!doneFile.exists()) {
                 Log.e("ERROR", "Failed to extract runtime")
                 throw Exception("Failed to extract runtime")
             } else {
@@ -112,7 +112,7 @@ class Bridge(private val applicationContext : Context, private var webview : Web
                     logdir = applicationContext.filesDir.absolutePath;
                 }
                 Log.d("ERLANG", "Starting beam...")
-                val ret = startErlang(releasedir, logdir!!)
+                val ret = startErlang(releaseDir, logdir!!)
                 Log.d("ERLANG", ret)
                 if (ret != "ok") {
                     throw Exception(ret)
@@ -122,10 +122,22 @@ class Bridge(private val applicationContext : Context, private var webview : Web
     }
 
 
-    private fun unpackZip(releasedir: String, inputStream: InputStream): Boolean
-    {
-        Log.d("RELEASEDIR", releasedir)
-        File(releasedir).mkdirs()
+    private fun unpackAsset(releaseDir: String, assetName: String): Boolean {
+        assets!!
+        if (assets!!.contains("$assetName.zip.xz")) {
+            val input = BufferedInputStream(applicationContext.assets.open("$assetName.zip.xz"))
+            return unpackZip(releaseDir, XZInputStream(input))
+        }
+        if (assets!!.contains("$assetName.zip")) {
+            val input = BufferedInputStream(applicationContext.assets.open("$assetName.zip"))
+            return unpackZip(releaseDir, input)
+        }
+        return false
+    }
+
+    private fun unpackZip(releaseDir: String, inputStream: InputStream): Boolean {
+        Log.d("RELEASEDIR", releaseDir)
+        File(releaseDir).mkdirs()
         try
         {
             val zis = ZipInputStream(BufferedInputStream(inputStream))
@@ -138,7 +150,7 @@ class Bridge(private val applicationContext : Context, private var webview : Web
 
                 // Need to create directories if not exists, or
                 // it will generate an Exception...
-                var fullpath = "$releasedir/$filename"
+                var fullpath = "$releaseDir/$filename"
                 if (ze.isDirectory) {
                     Log.d("DIR", fullpath)
                     File(fullpath).mkdirs()
@@ -216,8 +228,15 @@ class Bridge(private val applicationContext : Context, private var webview : Web
 
             var response = ref
             response += if (method == ":getOsDescription") {
-                val info = "Android ${Build.DEVICE} ${Build.BRAND} ${Build.VERSION.BASE_OS} ${Build.SUPPORTED_ABIS.joinToString(",")}"
+                val info = "Android ${Build.DEVICE} ${Build.BRAND} ${Build.VERSION.BASE_OS} ${
+                    Build.SUPPORTED_ABIS.joinToString(",")
+                }"
                 stringToList(info).toByteArray()
+            } else if (method == ":getCanonicalName") {
+                val primaryLocale = getCurrentLocale(applicationContext)
+                var locale = "${primaryLocale.language}_${primaryLocale.country}"
+                stringToList(locale).toByteArray()
+
             } else {
                 "use_mock".toByteArray()
             }
@@ -226,6 +245,14 @@ class Bridge(private val applicationContext : Context, private var webview : Web
         }
     }
 
+    fun getCurrentLocale(context: Context): Locale {
+        return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            context.resources.configuration.locales[0]
+        } else {
+            context.resources.configuration.locale
+        }
+    }
+
     private fun stringToList(str : String): String {
         val numbers = str.toByteArray().map { it.toInt().toString() }
         return "[${numbers.joinToString(",")}]"

app/src/main/java/org/tukaani/xz/ARMOptions.java

@@ -0,0 +1,37 @@
+/*
+ * ARMOptions
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import org.tukaani.xz.simple.ARM;
+
+/**
+ * BCJ filter for little endian ARM instructions.
+ */
+public class ARMOptions extends BCJOptions {
+    private static final int ALIGNMENT = 4;
+
+    public ARMOptions() {
+        super(ALIGNMENT);
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return new SimpleOutputStream(out, new ARM(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        return new SimpleInputStream(in, new ARM(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.ARM_FILTER_ID);
+    }
+}

app/src/main/java/org/tukaani/xz/ARMThumbOptions.java

@@ -0,0 +1,37 @@
+/*
+ * ARMThumbOptions
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import org.tukaani.xz.simple.ARMThumb;
+
+/**
+ * BCJ filter for little endian ARM-Thumb instructions.
+ */
+public class ARMThumbOptions extends BCJOptions {
+    private static final int ALIGNMENT = 2;
+
+    public ARMThumbOptions() {
+        super(ALIGNMENT);
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return new SimpleOutputStream(out, new ARMThumb(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        return new SimpleInputStream(in, new ARMThumb(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.ARMTHUMB_FILTER_ID);
+    }
+}

app/src/main/java/org/tukaani/xz/ArrayCache.java

@@ -0,0 +1,172 @@
+/*
+ * ArrayCache
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+/**
+ * Caches large arrays for reuse (base class and a dummy cache implementation).
+ * <p>
+ * When compressing or decompressing many (very) small files in a row, the
+ * time spent in construction of new compressor or decompressor objects
+ * can be longer than the time spent in actual compression or decompression.
+ * A large part of this initialization overhead comes from allocation and
+ * garbage collection of large arrays.
+ * <p>
+ * The {@code ArrayCache} API provides a way to cache large array allocations
+ * for reuse. It can give a major performance improvement when compressing or
+ * decompressing many tiny files. If you are only (de)compressing one or two
+ * files or the files a very big, array caching won't improve anything,
+ * although it won't make anything slower either.
+ * <p>
+ * <b>Important: The users of ArrayCache don't return the allocated arrays
+ * back to the cache in all situations.</b>
+ * This a reason why it's called a cache instead of a pool.
+ * If it is important to be able to return every array back to a cache,
+ * {@link ResettableArrayCache} can be useful.
+ * <p>
+ * In compressors (OutputStreams) the arrays are returned to the cache
+ * when a call to {@code finish()} or {@code close()} returns
+ * successfully (no exceptions are thrown).
+ * <p>
+ * In decompressors (InputStreams) the arrays are returned to the cache when
+ * the decompression is successfully finished ({@code read} returns {@code -1})
+ * or {@code close()} or {@code close(boolean)} is called. This is true even
+ * if closing throws an exception.
+ * <p>
+ * Raw decompressors don't support {@code close(boolean)}. With raw
+ * decompressors, if one wants to put the arrays back to the cache without
+ * closing the underlying {@code InputStream}, one can wrap the
+ * {@code InputStream} into {@link CloseIgnoringInputStream} when creating
+ * the decompressor instance. Then one can use {@code close()}.
+ * <p>
+ * Different cache implementations can be extended from this base class.
+ * All cache implementations must be thread safe.
+ * <p>
+ * This class also works as a dummy cache that simply calls {@code new}
+ * to allocate new arrays and doesn't try to cache anything. A statically
+ * allocated dummy cache is available via {@link #getDummyCache()}.
+ * <p>
+ * If no {@code ArrayCache} is specified when constructing a compressor or
+ * decompressor, the default {@code ArrayCache} implementation is used.
+ * See {@link #getDefaultCache()} and {@link #setDefaultCache(ArrayCache)}.
+ * <p>
+ * This is a class instead of an interface because it's possible that in the
+ * future we may want to cache other array types too. New methods can be
+ * added to this class without breaking existing cache implementations.
+ *
+ * @since 1.7
+ *
+ * @see BasicArrayCache
+ */
+public class ArrayCache {
+    /**
+     * Global dummy cache instance that is returned by {@code getDummyCache()}.
+     */
+    private static final ArrayCache dummyCache = new ArrayCache();
+
+    /**
+     * Global default {@code ArrayCache} that is used when no other cache has
+     * been specified.
+     */
+    private static volatile ArrayCache defaultCache = dummyCache;
+
+    /**
+     * Returns a statically-allocated {@code ArrayCache} instance.
+     * It can be shared by all code that needs a dummy cache.
+     */
+    public static ArrayCache getDummyCache() {
+        return dummyCache;
+    }
+
+    /**
+     * Gets the default {@code ArrayCache} instance.
+     * This is a global cache that is used when the application
+     * specifies nothing else. The default is a dummy cache
+     * (see {@link #getDummyCache()}).
+     */
+    public static ArrayCache getDefaultCache() {
+        // It's volatile so no need for synchronization.
+        return defaultCache;
+    }
+
+    /**
+     * Sets the default {@code ArrayCache} instance.
+     * Use with care. Other libraries using this package probably shouldn't
+     * call this function as libraries cannot know if there are other users
+     * of the xz package in the same application.
+     */
+    public static void setDefaultCache(ArrayCache arrayCache) {
+        if (arrayCache == null)
+            throw new NullPointerException();
+
+        // It's volatile so no need for synchronization.
+        defaultCache = arrayCache;
+    }
+
+    /**
+     * Creates a new {@code ArrayCache} that does no caching
+     * (a dummy cache). If you need a dummy cache, you may want to call
+     * {@link #getDummyCache()} instead.
+     */
+    public ArrayCache() {}
+
+    /**
+     * Allocates a new byte array.
+     * <p>
+     * This implementation simply returns {@code new byte[size]}.
+     *
+     * @param   size            the minimum size of the array to allocate;
+     *                          an implementation may return an array that
+     *                          is larger than the given {@code size}
+     *
+     * @param   fillWithZeros   if true, the caller expects that the first
+     *                          {@code size} elements in the array are zero;
+     *                          if false, the array contents can be anything,
+     *                          which speeds things up when reusing a cached
+     *                          array
+     */
+    public byte[] getByteArray(int size, boolean fillWithZeros) {
+        return new byte[size];
+    }
+
+    /**
+     * Puts the given byte array to the cache. The caller must no longer
+     * use the array.
+     * <p>
+     * This implementation does nothing.
+     */
+    public void putArray(byte[] array) {}
+
+    /**
+     * Allocates a new int array.
+     * <p>
+     * This implementation simply returns {@code new int[size]}.
+     *
+     * @param   size            the minimum size of the array to allocate;
+     *                          an implementation may return an array that
+     *                          is larger than the given {@code size}
+     *
+     * @param   fillWithZeros   if true, the caller expects that the first
+     *                          {@code size} elements in the array are zero;
+     *                          if false, the array contents can be anything,
+     *                          which speeds things up when reusing a cached
+     *                          array
+     */
+    public int[] getIntArray(int size, boolean fillWithZeros) {
+        return new int[size];
+    }
+
+    /**
+     * Puts the given int array to the cache. The caller must no longer
+     * use the array.
+     * <p>
+     * This implementation does nothing.
+     */
+    public void putArray(int[] array) {}
+}

app/src/main/java/org/tukaani/xz/BCJCoder.java

@@ -0,0 +1,35 @@
+/*
+ * BCJCoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+abstract class BCJCoder implements FilterCoder {
+    public static final long X86_FILTER_ID = 0x04;
+    public static final long POWERPC_FILTER_ID = 0x05;
+    public static final long IA64_FILTER_ID = 0x06;
+    public static final long ARM_FILTER_ID = 0x07;
+    public static final long ARMTHUMB_FILTER_ID = 0x08;
+    public static final long SPARC_FILTER_ID = 0x09;
+
+    public static boolean isBCJFilterID(long filterID) {
+        return filterID >= 0x04 && filterID <= 0x09;
+    }
+
+    public boolean changesSize() {
+        return false;
+    }
+
+    public boolean nonLastOK() {
+        return true;
+    }
+
+    public boolean lastOK() {
+        return false;
+    }
+}

app/src/main/java/org/tukaani/xz/BCJDecoder.java

@@ -0,0 +1,62 @@
+/*
+ * BCJDecoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import org.tukaani.xz.simple.*;
+
+class BCJDecoder extends BCJCoder implements FilterDecoder {
+    private final long filterID;
+    private final int startOffset;
+
+    BCJDecoder(long filterID, byte[] props)
+            throws UnsupportedOptionsException {
+        assert isBCJFilterID(filterID);
+        this.filterID = filterID;
+
+        if (props.length == 0) {
+            startOffset = 0;
+        } else if (props.length == 4) {
+            int n = 0;
+            for (int i = 0; i < 4; ++i)
+                n |= (props[i] & 0xFF) << (i * 8);
+
+            startOffset = n;
+        } else {
+            throw new UnsupportedOptionsException(
+                    "Unsupported BCJ filter properties");
+        }
+    }
+
+    public int getMemoryUsage() {
+        return SimpleInputStream.getMemoryUsage();
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        SimpleFilter simpleFilter = null;
+
+        if (filterID == X86_FILTER_ID)
+            simpleFilter = new X86(false, startOffset);
+        else if (filterID == POWERPC_FILTER_ID)
+            simpleFilter = new PowerPC(false, startOffset);
+        else if (filterID == IA64_FILTER_ID)
+            simpleFilter = new IA64(false, startOffset);
+        else if (filterID == ARM_FILTER_ID)
+            simpleFilter = new ARM(false, startOffset);
+        else if (filterID == ARMTHUMB_FILTER_ID)
+            simpleFilter = new ARMThumb(false, startOffset);
+        else if (filterID == SPARC_FILTER_ID)
+            simpleFilter = new SPARC(false, startOffset);
+        else
+            assert false;
+
+        return new SimpleInputStream(in, simpleFilter);
+    }
+}

app/src/main/java/org/tukaani/xz/BCJEncoder.java

@@ -0,0 +1,49 @@
+/*
+ * BCJEncoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+class BCJEncoder extends BCJCoder implements FilterEncoder {
+    private final BCJOptions options;
+    private final long filterID;
+    private final byte[] props;
+
+    BCJEncoder(BCJOptions options, long filterID) {
+        assert isBCJFilterID(filterID);
+        int startOffset = options.getStartOffset();
+
+        if (startOffset == 0) {
+            props = new byte[0];
+        } else {
+            props = new byte[4];
+            for (int i = 0; i < 4; ++i)
+                props[i] = (byte)(startOffset >>> (i * 8));
+        }
+
+        this.filterID = filterID;
+        this.options = (BCJOptions)options.clone();
+    }
+
+    public long getFilterID() {
+        return filterID;
+    }
+
+    public byte[] getFilterProps() {
+        return props;
+    }
+
+    public boolean supportsFlushing() {
+        return false;
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return options.getOutputStream(out, arrayCache);
+    }
+}

app/src/main/java/org/tukaani/xz/BCJOptions.java

@@ -0,0 +1,57 @@
+/*
+ * BCJOptions
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+abstract class BCJOptions extends FilterOptions {
+    private final int alignment;
+    int startOffset = 0;
+
+    BCJOptions(int alignment) {
+        this.alignment = alignment;
+    }
+
+    /**
+     * Sets the start offset for the address conversions.
+     * Normally this is useless so you shouldn't use this function.
+     * The default value is <code>0</code>.
+     */
+    public void setStartOffset(int startOffset)
+            throws UnsupportedOptionsException {
+        if ((startOffset & (alignment - 1)) != 0)
+            throw new UnsupportedOptionsException(
+                    "Start offset must be a multiple of " + alignment);
+
+        this.startOffset = startOffset;
+    }
+
+    /**
+     * Gets the start offset.
+     */
+    public int getStartOffset() {
+        return startOffset;
+    }
+
+    public int getEncoderMemoryUsage() {
+        return SimpleOutputStream.getMemoryUsage();
+    }
+
+    public int getDecoderMemoryUsage() {
+        return SimpleInputStream.getMemoryUsage();
+    }
+
+    public Object clone() {
+        try {
+            return super.clone();
+        } catch (CloneNotSupportedException e) {
+            assert false;
+            throw new RuntimeException();
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/BasicArrayCache.java

@@ -0,0 +1,281 @@
+/*
+ * BasicArrayCache
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.lang.ref.Reference;
+import java.lang.ref.SoftReference;
+import java.util.Arrays;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * A basic {@link ArrayCache} implementation.
+ * <p>
+ * This caches exact array sizes, that is, {@code getByteArray} will return
+ * an array whose size is exactly the requested size. A limited number
+ * of different array sizes are cached at the same time; least recently used
+ * sizes will be dropped from the cache if needed (can happen if several
+ * different (de)compression options are used with the same cache).
+ * <p>
+ * The current implementation uses
+ * {@link java.util.LinkedHashMap LinkedHashMap} to map different array sizes
+ * to separate array-based data structures which hold
+ * {@link java.lang.ref.SoftReference SoftReferences} to the cached arrays.
+ * In the common case this should give good performance and fairly low
+ * memory usage overhead.
+ * <p>
+ * A statically allocated global {@code BasicArrayCache} instance is
+ * available via {@link #getInstance()} which is a good choice in most
+ * situations where caching is wanted.
+ *
+ * @since 1.7
+ */
+public class BasicArrayCache extends ArrayCache {
+    /**
+     * Arrays smaller than this many elements will not be cached.
+     */
+    private static final int CACHEABLE_SIZE_MIN = 32 << 10;
+
+    /**
+     * Number of stacks i.e. how many different array sizes to cache.
+     */
+    private static final int STACKS_MAX = 32;
+
+    /**
+     * Number of arrays of the same type and size to keep in the cache.
+     * (ELEMENTS_PER_STACK - 1) is used as a bit mask so ELEMENTS_PER_STACK
+     * must be a power of two!
+     */
+    private static final int ELEMENTS_PER_STACK = 512;
+
+    /**
+     * A thread-safe stack-like data structure whose {@code push} method
+     * overwrites the oldest element in the stack if the stack is full.
+     */
+    private static class CyclicStack<T> {
+        /**
+         * Array that holds the elements in the cyclic stack.
+         */
+        @SuppressWarnings("unchecked")
+        private final T[] elements = (T[])new Object[ELEMENTS_PER_STACK];
+
+        /**
+         * Read-write position in the {@code refs} array.
+         * The most recently added element is in {@code refs[pos]}.
+         * If it is {@code null}, then the stack is empty and all
+         * elements in {@code refs} are {@code null}.
+         * <p>
+         * Note that {@code pop()} always modifies {@code pos}, even if
+         * the stack is empty. This means that when the first element is
+         * added by {@code push(T)}, it can get added in any position in
+         * {@code refs} and the stack will start growing from there.
+         */
+        private int pos = 0;
+
+        /**
+         * Gets the most recently added element from the stack.
+         * If the stack is empty, {@code null} is returned.
+         */
+        public synchronized T pop() {
+            T e = elements[pos];
+            elements[pos] = null;
+            pos = (pos - 1) & (ELEMENTS_PER_STACK - 1);
+            return e;
+        }
+
+        /**
+         * Adds a new element to the stack. If the stack is full, the oldest
+         * element is overwritten.
+         */
+        public synchronized void push(T e) {
+            pos = (pos + 1) & (ELEMENTS_PER_STACK - 1);
+            elements[pos] = e;
+        }
+    }
+
+    /**
+     * Maps Integer (array size) to stacks of references to arrays. At most
+     * STACKS_MAX number of stacks are kept in the map (LRU cache).
+     */
+    private static class CacheMap<T>
+            extends LinkedHashMap<Integer, CyclicStack<Reference<T>>> {
+        /**
+         * This class won't be serialized but this is needed
+         * to silence a compiler warning.
+         */
+        private static final long serialVersionUID = 1L;
+
+        /**
+         * Creates a new CacheMap.
+         */
+        public CacheMap() {
+            // The map may momentarily have at most STACKS_MAX + 1 entries
+            // when put(K,V) has inserted a new entry but hasn't called
+            // removeEldestEntry yet. Using 2 * STACKS_MAX as the initial
+            // (and the final) capacity should give good performance. 0.75 is
+            // the default load factor and in this case it guarantees that
+            // the map will never need to be rehashed because
+            // (STACKS_MAX + 1) / 0.75 < 2 * STACKS_MAX.
+            //
+            // That last argument is true to get LRU cache behavior together
+            // with the overriden removeEldestEntry method.
+            super(2 * STACKS_MAX, 0.75f, true);
+        }
+
+        /**
+         * Returns true if the map is full and the least recently used stack
+         * should be removed.
+         */
+        protected boolean removeEldestEntry(
+                Map.Entry<Integer, CyclicStack<Reference<T>>> eldest) {
+            return size() > STACKS_MAX;
+        }
+    }
+
+    /**
+     * Helper class for the singleton instance.
+     * This is allocated only if {@code getInstance()} is called.
+     */
+    private static final class LazyHolder {
+        static final BasicArrayCache INSTANCE = new BasicArrayCache();
+    }
+
+    /**
+     * Returns a statically-allocated {@code BasicArrayCache} instance.
+     * This is often a good choice when a cache is needed.
+     */
+    public static BasicArrayCache getInstance() {
+        return LazyHolder.INSTANCE;
+    }
+
+    /**
+     * Stacks for cached byte arrays.
+     */
+    private final CacheMap<byte[]> byteArrayCache = new CacheMap<byte[]>();
+
+    /**
+     * Stacks for cached int arrays.
+     */
+    private final CacheMap<int[]> intArrayCache = new CacheMap<int[]>();
+
+    /**
+     * Gets {@code T[size]} from the given {@code cache}.
+     * If no such array is found, {@code null} is returned.
+     */
+    private static <T> T getArray(CacheMap<T> cache, int size) {
+        // putArray doesn't add small arrays to the cache and so it's
+        // pointless to look for small arrays here.
+        if (size < CACHEABLE_SIZE_MIN)
+            return null;
+
+        // Try to find a stack that holds arrays of T[size].
+        CyclicStack<Reference<T>> stack;
+        synchronized(cache) {
+            stack = cache.get(size);
+        }
+
+        if (stack == null)
+            return null;
+
+        // Try to find a non-cleared Reference from the stack.
+        T array;
+        do {
+            Reference<T> r = stack.pop();
+            if (r == null)
+                return null;
+
+            array = r.get();
+        } while (array == null);
+
+        return array;
+    }
+
+    /**
+     * Puts the {@code array} of {@code size} elements long into
+     * the {@code cache}.
+     */
+    private static <T> void putArray(CacheMap<T> cache, T array, int size) {
+        // Small arrays aren't cached.
+        if (size < CACHEABLE_SIZE_MIN)
+            return;
+
+        CyclicStack<Reference<T>> stack;
+
+        synchronized(cache) {
+            // Get a stack that holds arrays of T[size]. If no such stack
+            // exists, allocate a new one. If the cache already had STACKS_MAX
+            // number of stacks, the least recently used stack is removed by
+            // cache.put (it calls removeEldestEntry).
+            stack = cache.get(size);
+            if (stack == null) {
+                stack = new CyclicStack<Reference<T>>();
+                cache.put(size, stack);
+            }
+        }
+
+        stack.push(new SoftReference<T>(array));
+    }
+
+    /**
+     * Allocates a new byte array, hopefully reusing an existing
+     * array from the cache.
+     *
+     * @param       size        size of the array to allocate
+     *
+     * @param       fillWithZeros
+     *                          if true, all the elements of the returned
+     *                          array will be zero; if false, the contents
+     *                          of the returned array is undefined
+     */
+    public byte[] getByteArray(int size, boolean fillWithZeros) {
+        byte[] array = getArray(byteArrayCache, size);
+
+        if (array == null)
+            array = new byte[size];
+        else if (fillWithZeros)
+            Arrays.fill(array, (byte)0x00);
+
+        return array;
+    }
+
+    /**
+     * Puts the given byte array to the cache. The caller must no longer
+     * use the array.
+     * <p>
+     * Small arrays aren't cached and will be ignored by this method.
+     */
+    public void putArray(byte[] array) {
+        putArray(byteArrayCache, array, array.length);
+    }
+
+    /**
+     * This is like getByteArray but for int arrays.
+     */
+    public int[] getIntArray(int size, boolean fillWithZeros) {
+        int[] array = getArray(intArrayCache, size);
+
+        if (array == null)
+            array = new int[size];
+        else if (fillWithZeros)
+            Arrays.fill(array, 0);
+
+        return array;
+    }
+
+    /**
+     * Puts the given int array to the cache. The caller must no longer
+     * use the array.
+     * <p>
+     * Small arrays aren't cached and will be ignored by this method.
+     */
+    public void putArray(int[] array) {
+        putArray(intArrayCache, array, array.length);
+    }
+}

app/src/main/java/org/tukaani/xz/BlockInputStream.java

@@ -0,0 +1,306 @@
+/*
+ * BlockInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.DataInputStream;
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.util.Arrays;
+import org.tukaani.xz.common.DecoderUtil;
+import org.tukaani.xz.check.Check;
+
+class BlockInputStream extends InputStream {
+    private final DataInputStream inData;
+    private final CountingInputStream inCounted;
+    private InputStream filterChain;
+    private final Check check;
+    private final boolean verifyCheck;
+
+    private long uncompressedSizeInHeader = -1;
+    private long compressedSizeInHeader = -1;
+    private long compressedSizeLimit;
+    private final int headerSize;
+    private long uncompressedSize = 0;
+    private boolean endReached = false;
+
+    private final byte[] tempBuf = new byte[1];
+
+    public BlockInputStream(InputStream in,
+                            Check check, boolean verifyCheck,
+                            int memoryLimit,
+                            long unpaddedSizeInIndex,
+                            long uncompressedSizeInIndex,
+                            ArrayCache arrayCache)
+            throws IOException, IndexIndicatorException {
+        this.check = check;
+        this.verifyCheck = verifyCheck;
+        inData = new DataInputStream(in);
+
+        // Block Header Size or Index Indicator
+        int b = inData.readUnsignedByte();
+
+        // See if this begins the Index field.
+        if (b == 0x00)
+            throw new IndexIndicatorException();
+
+        // Read the rest of the Block Header.
+        headerSize = 4 * (b + 1);
+
+        final byte[] buf = new byte[headerSize];
+        buf[0] = (byte)b;
+        inData.readFully(buf, 1, headerSize - 1);
+
+        // Validate the CRC32.
+        if (!DecoderUtil.isCRC32Valid(buf, 0, headerSize - 4, headerSize - 4))
+            throw new CorruptedInputException("XZ Block Header is corrupt");
+
+        // Check for reserved bits in Block Flags.
+        if ((buf[1] & 0x3C) != 0)
+            throw new UnsupportedOptionsException(
+                    "Unsupported options in XZ Block Header");
+
+        // Memory for the Filter Flags field
+        int filterCount = (buf[1] & 0x03) + 1;
+        long[] filterIDs = new long[filterCount];
+        byte[][] filterProps = new byte[filterCount][];
+
+        // Use a stream to parse the fields after the Block Flags field.
+        // Exclude the CRC32 field at the end.
+        ByteArrayInputStream bufStream = new ByteArrayInputStream(
+                buf, 2, headerSize - 6);
+
+        try {
+            // Set the maximum valid compressed size. This is overriden
+            // by the value from the Compressed Size field if it is present.
+            compressedSizeLimit = (DecoderUtil.VLI_MAX & ~3)
+                                  - headerSize - check.getSize();
+
+            // Decode and validate Compressed Size if the relevant flag
+            // is set in Block Flags.
+            if ((buf[1] & 0x40) != 0x00) {
+                compressedSizeInHeader = DecoderUtil.decodeVLI(bufStream);
+
+                if (compressedSizeInHeader == 0
+                        || compressedSizeInHeader > compressedSizeLimit)
+                    throw new CorruptedInputException();
+
+                compressedSizeLimit = compressedSizeInHeader;
+            }
+
+            // Decode Uncompressed Size if the relevant flag is set
+            // in Block Flags.
+            if ((buf[1] & 0x80) != 0x00)
+                uncompressedSizeInHeader = DecoderUtil.decodeVLI(bufStream);
+
+            // Decode Filter Flags.
+            for (int i = 0; i < filterCount; ++i) {
+                filterIDs[i] = DecoderUtil.decodeVLI(bufStream);
+
+                long filterPropsSize = DecoderUtil.decodeVLI(bufStream);
+                if (filterPropsSize > bufStream.available())
+                    throw new CorruptedInputException();
+
+                filterProps[i] = new byte[(int)filterPropsSize];
+                bufStream.read(filterProps[i]);
+            }
+
+        } catch (IOException e) {
+            throw new CorruptedInputException("XZ Block Header is corrupt");
+        }
+
+        // Check that the remaining bytes are zero.
+        for (int i = bufStream.available(); i > 0; --i)
+            if (bufStream.read() != 0x00)
+                throw new UnsupportedOptionsException(
+                        "Unsupported options in XZ Block Header");
+
+        // Validate the Blcok Header against the Index when doing
+        // random access reading.
+        if (unpaddedSizeInIndex != -1) {
+            // Compressed Data must be at least one byte, so if Block Header
+            // and Check alone take as much or more space than the size
+            // stored in the Index, the file is corrupt.
+            int headerAndCheckSize = headerSize + check.getSize();
+            if (headerAndCheckSize >= unpaddedSizeInIndex)
+                throw new CorruptedInputException(
+                        "XZ Index does not match a Block Header");
+
+            // The compressed size calculated from Unpadded Size must
+            // match the value stored in the Compressed Size field in
+            // the Block Header.
+            long compressedSizeFromIndex
+                    = unpaddedSizeInIndex - headerAndCheckSize;
+            if (compressedSizeFromIndex > compressedSizeLimit
+                    || (compressedSizeInHeader != -1
+                        && compressedSizeInHeader != compressedSizeFromIndex))
+                throw new CorruptedInputException(
+                        "XZ Index does not match a Block Header");
+
+            // The uncompressed size stored in the Index must match
+            // the value stored in the Uncompressed Size field in
+            // the Block Header.
+            if (uncompressedSizeInHeader != -1
+                    && uncompressedSizeInHeader != uncompressedSizeInIndex)
+                throw new CorruptedInputException(
+                        "XZ Index does not match a Block Header");
+
+            // For further validation, pretend that the values from the Index
+            // were stored in the Block Header.
+            compressedSizeLimit = compressedSizeFromIndex;
+            compressedSizeInHeader = compressedSizeFromIndex;
+            uncompressedSizeInHeader = uncompressedSizeInIndex;
+        }
+
+        // Check if the Filter IDs are supported, decode
+        // the Filter Properties, and check that they are
+        // supported by this decoder implementation.
+        FilterDecoder[] filters = new FilterDecoder[filterIDs.length];
+
+        for (int i = 0; i < filters.length; ++i) {
+            if (filterIDs[i] == LZMA2Coder.FILTER_ID)
+                filters[i] = new LZMA2Decoder(filterProps[i]);
+
+            else if (filterIDs[i] == DeltaCoder.FILTER_ID)
+                filters[i] = new DeltaDecoder(filterProps[i]);
+
+            else if (BCJDecoder.isBCJFilterID(filterIDs[i]))
+                filters[i] = new BCJDecoder(filterIDs[i], filterProps[i]);
+
+            else
+                throw new UnsupportedOptionsException(
+                        "Unknown Filter ID " + filterIDs[i]);
+        }
+
+        RawCoder.validate(filters);
+
+        // Check the memory usage limit.
+        if (memoryLimit >= 0) {
+            int memoryNeeded = 0;
+            for (int i = 0; i < filters.length; ++i)
+                memoryNeeded += filters[i].getMemoryUsage();
+
+            if (memoryNeeded > memoryLimit)
+                throw new MemoryLimitException(memoryNeeded, memoryLimit);
+        }
+
+        // Use an input size counter to calculate
+        // the size of the Compressed Data field.
+        inCounted = new CountingInputStream(in);
+
+        // Initialize the filter chain.
+        filterChain = inCounted;
+        for (int i = filters.length - 1; i >= 0; --i)
+            filterChain = filters[i].getInputStream(filterChain, arrayCache);
+    }
+
+    public int read() throws IOException {
+        return read(tempBuf, 0, 1) == -1 ? -1 : (tempBuf[0] & 0xFF);
+    }
+
+    public int read(byte[] buf, int off, int len) throws IOException {
+        if (endReached)
+            return -1;
+
+        int ret = filterChain.read(buf, off, len);
+
+        if (ret > 0) {
+            if (verifyCheck)
+                check.update(buf, off, ret);
+
+            uncompressedSize += ret;
+
+            // Catch invalid values.
+            long compressedSize = inCounted.getSize();
+            if (compressedSize < 0
+                    || compressedSize > compressedSizeLimit
+                    || uncompressedSize < 0
+                    || (uncompressedSizeInHeader != -1
+                        && uncompressedSize > uncompressedSizeInHeader))
+                throw new CorruptedInputException();
+
+            // Check the Block integrity as soon as possible:
+            //   - The filter chain shouldn't return less than requested
+            //     unless it hit the end of the input.
+            //   - If the uncompressed size is known, we know when there
+            //     shouldn't be more data coming. We still need to read
+            //     one byte to let the filter chain catch errors and to
+            //     let it read end of payload marker(s).
+            if (ret < len || uncompressedSize == uncompressedSizeInHeader) {
+                if (filterChain.read() != -1)
+                    throw new CorruptedInputException();
+
+                validate();
+                endReached = true;
+            }
+        } else if (ret == -1) {
+            validate();
+            endReached = true;
+        }
+
+        return ret;
+    }
+
+    private void validate() throws IOException {
+        long compressedSize = inCounted.getSize();
+
+        // Validate Compressed Size and Uncompressed Size if they were
+        // present in Block Header.
+        if ((compressedSizeInHeader != -1
+                    && compressedSizeInHeader != compressedSize)
+                || (uncompressedSizeInHeader != -1
+                    && uncompressedSizeInHeader != uncompressedSize))
+            throw new CorruptedInputException();
+
+        // Block Padding bytes must be zeros.
+        while ((compressedSize++ & 3) != 0)
+            if (inData.readUnsignedByte() != 0x00)
+                throw new CorruptedInputException();
+
+        // Validate the integrity check if verifyCheck is true.
+        byte[] storedCheck = new byte[check.getSize()];
+        inData.readFully(storedCheck);
+        if (verifyCheck && !Arrays.equals(check.finish(), storedCheck))
+            throw new CorruptedInputException("Integrity check ("
+                    + check.getName() + ") does not match");
+    }
+
+    public int available() throws IOException {
+        return filterChain.available();
+    }
+
+    public void close() {
+        // This puts all arrays, that were allocated from ArrayCache,
+        // back to the ArrayCache. The last filter in the chain will
+        // call inCounted.close() which, being an instance of
+        // CloseIgnoringInputStream, won't close() the InputStream that
+        // was provided by the application.
+        try {
+            filterChain.close();
+        } catch (IOException e) {
+            // It's a bug if we get here. The InputStreams that we are closing
+            // are all from this package and they are known to not throw
+            // IOException. (They could throw an IOException if we were
+            // closing the application-supplied InputStream, but
+            // inCounted.close() doesn't do that.)
+            assert false;
+        }
+
+        filterChain = null;
+    }
+
+    public long getUnpaddedSize() {
+        return headerSize + inCounted.getSize() + check.getSize();
+    }
+
+    public long getUncompressedSize() {
+        return uncompressedSize;
+    }
+}

app/src/main/java/org/tukaani/xz/BlockOutputStream.java

@@ -0,0 +1,135 @@
+/*
+ * BlockOutputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.OutputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import org.tukaani.xz.common.EncoderUtil;
+import org.tukaani.xz.check.Check;
+
+class BlockOutputStream extends FinishableOutputStream {
+    private final OutputStream out;
+    private final CountingOutputStream outCounted;
+    private FinishableOutputStream filterChain;
+    private final Check check;
+
+    private final int headerSize;
+    private final long compressedSizeLimit;
+    private long uncompressedSize = 0;
+
+    private final byte[] tempBuf = new byte[1];
+
+    public BlockOutputStream(OutputStream out, FilterEncoder[] filters,
+                             Check check, ArrayCache arrayCache)
+            throws IOException {
+        this.out = out;
+        this.check = check;
+
+        // Initialize the filter chain.
+        outCounted = new CountingOutputStream(out);
+        filterChain = outCounted;
+        for (int i = filters.length - 1; i >= 0; --i)
+            filterChain = filters[i].getOutputStream(filterChain, arrayCache);
+
+        // Prepare to encode the Block Header field.
+        ByteArrayOutputStream bufStream = new ByteArrayOutputStream();
+
+        // Write a dummy Block Header Size field. The real value is written
+        // once everything else except CRC32 has been written.
+        bufStream.write(0x00);
+
+        // Write Block Flags. Storing Compressed Size or Uncompressed Size
+        // isn't supported for now.
+        bufStream.write(filters.length - 1);
+
+        // List of Filter Flags
+        for (int i = 0; i < filters.length; ++i) {
+            EncoderUtil.encodeVLI(bufStream, filters[i].getFilterID());
+            byte[] filterProps = filters[i].getFilterProps();
+            EncoderUtil.encodeVLI(bufStream, filterProps.length);
+            bufStream.write(filterProps);
+        }
+
+        // Header Padding
+        while ((bufStream.size() & 3) != 0)
+            bufStream.write(0x00);
+
+        byte[] buf = bufStream.toByteArray();
+
+        // Total size of the Block Header: Take the size of the CRC32 field
+        // into account.
+        headerSize = buf.length + 4;
+
+        // This is just a sanity check.
+        if (headerSize > EncoderUtil.BLOCK_HEADER_SIZE_MAX)
+            throw new UnsupportedOptionsException();
+
+        // Block Header Size
+        buf[0] = (byte)(buf.length / 4);
+
+        // Write the Block Header field to the output stream.
+        out.write(buf);
+        EncoderUtil.writeCRC32(out, buf);
+
+        // Calculate the maximum allowed size of the Compressed Data field.
+        // It is hard to exceed it so this is mostly to be pedantic.
+        compressedSizeLimit = (EncoderUtil.VLI_MAX & ~3)
+                              - headerSize - check.getSize();
+    }
+
+    public void write(int b) throws IOException {
+        tempBuf[0] = (byte)b;
+        write(tempBuf, 0, 1);
+    }
+
+    public void write(byte[] buf, int off, int len) throws IOException {
+        filterChain.write(buf, off, len);
+        check.update(buf, off, len);
+        uncompressedSize += len;
+        validate();
+    }
+
+    public void flush() throws IOException {
+        filterChain.flush();
+        validate();
+    }
+
+    public void finish() throws IOException {
+        // Finish the Compressed Data field.
+        filterChain.finish();
+        validate();
+
+        // Block Padding
+        for (long i = outCounted.getSize(); (i & 3) != 0; ++i)
+            out.write(0x00);
+
+        // Check
+        out.write(check.finish());
+    }
+
+    private void validate() throws IOException {
+        long compressedSize = outCounted.getSize();
+
+        // It is very hard to trigger this exception.
+        // This is just to be pedantic.
+        if (compressedSize < 0 || compressedSize > compressedSizeLimit
+                || uncompressedSize < 0)
+            throw new XZIOException("XZ Stream has grown too big");
+    }
+
+    public long getUnpaddedSize() {
+        return headerSize + outCounted.getSize() + check.getSize();
+    }
+
+    public long getUncompressedSize() {
+        return uncompressedSize;
+    }
+}

app/src/main/java/org/tukaani/xz/CloseIgnoringInputStream.java

@@ -0,0 +1,48 @@
+/*
+ * CloseIgnoringInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.FilterInputStream;
+
+/**
+ * An {@code InputStream} wrapper whose {@code close()} does nothing.
+ * This is useful with raw decompressors if you want to call
+ * {@code close()} to release memory allocated from an {@link ArrayCache}
+ * but don't want to close the underlying {@code InputStream}.
+ * For example:
+ * <blockquote><pre>
+ * InputStream rawdec = new LZMA2InputStream(
+ *         new CloseIgnoringInputStream(myInputStream),
+ *         myDictSize, null, myArrayCache);
+ * doSomething(rawdec);
+ * rawdec.close(); // This doesn't close myInputStream.
+ * </pre></blockquote>
+ * <p>
+ * With {@link XZInputStream}, {@link SingleXZInputStream}, and
+ * {@link SeekableXZInputStream} you can use their {@code close(boolean)}
+ * method to avoid closing the underlying {@code InputStream}; with
+ * those classes {@code CloseIgnoringInputStream} isn't needed.
+ *
+ * @since 1.7
+ */
+public class CloseIgnoringInputStream extends FilterInputStream {
+    /**
+     * Creates a new {@code CloseIgnoringInputStream}.
+     */
+    public CloseIgnoringInputStream(InputStream in) {
+        super(in);
+    }
+
+    /**
+     * This does nothing (doesn't call {@code in.close()}).
+     */
+    public void close() {}
+}

app/src/main/java/org/tukaani/xz/CorruptedInputException.java

@@ -0,0 +1,37 @@
+/*
+ * CorruptedInputException
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+/**
+ * Thrown when the compressed input data is corrupt.
+ * However, it is possible that some or all of the data
+ * already read from the input stream was corrupt too.
+ */
+public class CorruptedInputException extends XZIOException {
+    private static final long serialVersionUID = 3L;
+
+    /**
+     * Creates a new CorruptedInputException with
+     * the default error detail message.
+     */
+    public CorruptedInputException() {
+        super("Compressed data is corrupt");
+    }
+
+    /**
+     * Creates a new CorruptedInputException with
+     * the specified error detail message.
+     *
+     * @param       s           error detail message
+     */
+    public CorruptedInputException(String s) {
+        super(s);
+    }
+}

app/src/main/java/org/tukaani/xz/CountingInputStream.java

@@ -0,0 +1,47 @@
+/*
+ * CountingInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.FilterInputStream;
+import java.io.InputStream;
+import java.io.IOException;
+
+/**
+ * Counts the number of bytes read from an input stream.
+ * The <code>close()</code> method does nothing, that is, the underlying
+ * <code>InputStream</code> isn't closed.
+ */
+class CountingInputStream extends CloseIgnoringInputStream {
+    private long size = 0;
+
+    public CountingInputStream(InputStream in) {
+        super(in);
+    }
+
+    public int read() throws IOException {
+        int ret = in.read();
+        if (ret != -1 && size >= 0)
+            ++size;
+
+        return ret;
+    }
+
+    public int read(byte[] b, int off, int len) throws IOException {
+        int ret = in.read(b, off, len);
+        if (ret > 0 && size >= 0)
+            size += ret;
+
+        return ret;
+    }
+
+    public long getSize() {
+        return size;
+    }
+}

app/src/main/java/org/tukaani/xz/CountingOutputStream.java

@@ -0,0 +1,54 @@
+/*
+ * CountingOutputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.OutputStream;
+import java.io.IOException;
+
+/**
+ * Counts the number of bytes written to an output stream.
+ * <p>
+ * The <code>finish</code> method does nothing.
+ * This is <code>FinishableOutputStream</code> instead
+ * of <code>OutputStream</code> solely because it allows
+ * using this as the output stream for a chain of raw filters.
+ */
+class CountingOutputStream extends FinishableOutputStream {
+    private final OutputStream out;
+    private long size = 0;
+
+    public CountingOutputStream(OutputStream out) {
+        this.out = out;
+    }
+
+    public void write(int b) throws IOException {
+        out.write(b);
+        if (size >= 0)
+            ++size;
+    }
+
+    public void write(byte[] b, int off, int len) throws IOException {
+        out.write(b, off, len);
+        if (size >= 0)
+            size += len;
+    }
+
+    public void flush() throws IOException {
+        out.flush();
+    }
+
+    public void close() throws IOException {
+        out.close();
+    }
+
+    public long getSize() {
+        return size;
+    }
+}

app/src/main/java/org/tukaani/xz/DeltaCoder.java

@@ -0,0 +1,26 @@
+/*
+ * DeltaCoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+abstract class DeltaCoder implements FilterCoder {
+    public static final long FILTER_ID = 0x03;
+
+    public boolean changesSize() {
+        return false;
+    }
+
+    public boolean nonLastOK() {
+        return true;
+    }
+
+    public boolean lastOK() {
+        return false;
+    }
+}

app/src/main/java/org/tukaani/xz/DeltaDecoder.java

@@ -0,0 +1,32 @@
+/*
+ * DeltaDecoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+
+class DeltaDecoder extends DeltaCoder implements FilterDecoder {
+    private final int distance;
+
+    DeltaDecoder(byte[] props) throws UnsupportedOptionsException {
+        if (props.length != 1)
+            throw new UnsupportedOptionsException(
+                    "Unsupported Delta filter properties");
+
+        distance = (props[0] & 0xFF) + 1;
+    }
+
+    public int getMemoryUsage() {
+        return 1;
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        return new DeltaInputStream(in, distance);
+    }
+}

app/src/main/java/org/tukaani/xz/DeltaEncoder.java

@@ -0,0 +1,37 @@
+/*
+ * DeltaEncoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+class DeltaEncoder extends DeltaCoder implements FilterEncoder {
+    private final DeltaOptions options;
+    private final byte[] props = new byte[1];
+
+    DeltaEncoder(DeltaOptions options) {
+        props[0] = (byte)(options.getDistance() - 1);
+        this.options = (DeltaOptions)options.clone();
+    }
+
+    public long getFilterID() {
+        return FILTER_ID;
+    }
+
+    public byte[] getFilterProps() {
+        return props;
+    }
+
+    public boolean supportsFlushing() {
+        return true;
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return options.getOutputStream(out, arrayCache);
+    }
+}

app/src/main/java/org/tukaani/xz/DeltaInputStream.java

@@ -0,0 +1,146 @@
+/*
+ * DeltaInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.IOException;
+import org.tukaani.xz.delta.DeltaDecoder;
+
+/**
+ * Decodes raw Delta-filtered data (no XZ headers).
+ * <p>
+ * The delta filter doesn't change the size of the data and thus it
+ * cannot have an end-of-payload marker. It will simply decode until
+ * its input stream indicates end of input.
+ */
+public class DeltaInputStream extends InputStream {
+    /**
+     * Smallest supported delta calculation distance.
+     */
+    public static final int DISTANCE_MIN = 1;
+
+    /**
+     * Largest supported delta calculation distance.
+     */
+    public static final int DISTANCE_MAX = 256;
+
+    private InputStream in;
+    private final DeltaDecoder delta;
+
+    private IOException exception = null;
+
+    private final byte[] tempBuf = new byte[1];
+
+    /**
+     * Creates a new Delta decoder with the given delta calculation distance.
+     *
+     * @param       in          input stream from which Delta filtered data
+     *                          is read
+     *
+     * @param       distance    delta calculation distance, must be in the
+     *                          range [<code>DISTANCE_MIN</code>,
+     *                          <code>DISTANCE_MAX</code>]
+     */
+    public DeltaInputStream(InputStream in, int distance) {
+        // Check for null because otherwise null isn't detect
+        // in this constructor.
+        if (in == null)
+            throw new NullPointerException();
+
+        this.in = in;
+        this.delta = new DeltaDecoder(distance);
+    }
+
+    /**
+     * Decode the next byte from this input stream.
+     *
+     * @return      the next decoded byte, or <code>-1</code> to indicate
+     *              the end of input on the input stream <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public int read() throws IOException {
+        return read(tempBuf, 0, 1) == -1 ? -1 : (tempBuf[0] & 0xFF);
+    }
+
+    /**
+     * Decode into an array of bytes.
+     * <p>
+     * This calls <code>in.read(buf, off, len)</code> and defilters the
+     * returned data.
+     *
+     * @param       buf         target buffer for decoded data
+     * @param       off         start offset in <code>buf</code>
+     * @param       len         maximum number of bytes to read
+     *
+     * @return      number of bytes read, or <code>-1</code> to indicate
+     *              the end of the input stream <code>in</code>
+     *
+     * @throws      XZIOException if the stream has been closed
+     *
+     * @throws      IOException may be thrown by underlaying input
+     *                          stream <code>in</code>
+     */
+    public int read(byte[] buf, int off, int len) throws IOException {
+        if (len == 0)
+            return 0;
+
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        int size;
+        try {
+            size = in.read(buf, off, len);
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+
+        if (size == -1)
+            return -1;
+
+        delta.decode(buf, off, size);
+        return size;
+    }
+
+    /**
+     * Calls <code>in.available()</code>.
+     *
+     * @return      the value returned by <code>in.available()</code>
+     */
+    public int available() throws IOException {
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        return in.available();
+    }
+
+    /**
+     * Closes the stream and calls <code>in.close()</code>.
+     * If the stream was already closed, this does nothing.
+     *
+     * @throws  IOException if thrown by <code>in.close()</code>
+     */
+    public void close() throws IOException {
+        if (in != null) {
+            try {
+                in.close();
+            } finally {
+                in = null;
+            }
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/DeltaOptions.java

@@ -0,0 +1,103 @@
+/*
+ * DeltaOptions
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+
+/**
+ * Delta filter options. The Delta filter can be used only as a non-last
+ * filter in the chain, for example Delta + LZMA2.
+ * <p>
+ * Currently only simple byte-wise delta is supported. The only option
+ * is the delta distance, which you should set to match your data.
+ * It's not possible to provide a generic default value for it.
+ * <p>
+ * For example, with distance = 2 and eight-byte input
+ * A1 B1 A2 B3 A3 B5 A4 B7, the output will be A1 B1 01 02 01 02 01 02.
+ * <p>
+ * The Delta filter can be good with uncompressed bitmap images. It can
+ * also help with PCM audio, although special-purpose compressors like
+ * FLAC will give much smaller result at much better compression speed.
+ */
+public class DeltaOptions extends FilterOptions {
+    /**
+     * Smallest supported delta calculation distance.
+     */
+    public static final int DISTANCE_MIN = 1;
+
+    /**
+     * Largest supported delta calculation distance.
+     */
+    public static final int DISTANCE_MAX = 256;
+
+    private int distance = DISTANCE_MIN;
+
+    /**
+     * Creates new Delta options and sets the delta distance to 1 byte.
+     */
+    public DeltaOptions() {}
+
+    /**
+     * Creates new Delta options and sets the distance to the given value.
+     */
+    public DeltaOptions(int distance) throws UnsupportedOptionsException {
+        setDistance(distance);
+    }
+
+    /**
+     * Sets the delta distance in bytes. The new distance must be in
+     * the range [DISTANCE_MIN, DISTANCE_MAX].
+     */
+    public void setDistance(int distance) throws UnsupportedOptionsException {
+        if (distance < DISTANCE_MIN || distance > DISTANCE_MAX)
+            throw new UnsupportedOptionsException(
+                    "Delta distance must be in the range [" + DISTANCE_MIN
+                    + ", " + DISTANCE_MAX + "]: " + distance);
+
+        this.distance = distance;
+    }
+
+    /**
+     * Gets the delta distance.
+     */
+    public int getDistance() {
+        return distance;
+    }
+
+    public int getEncoderMemoryUsage() {
+        return DeltaOutputStream.getMemoryUsage();
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return new DeltaOutputStream(out, this);
+    }
+
+    public int getDecoderMemoryUsage() {
+        return 1;
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        return new DeltaInputStream(in, distance);
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new DeltaEncoder(this);
+    }
+
+    public Object clone() {
+        try {
+            return super.clone();
+        } catch (CloneNotSupportedException e) {
+            assert false;
+            throw new RuntimeException();
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/DeltaOutputStream.java

@@ -0,0 +1,113 @@
+/*
+ * DeltaOutputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.IOException;
+import org.tukaani.xz.delta.DeltaEncoder;
+
+class DeltaOutputStream extends FinishableOutputStream {
+    private static final int FILTER_BUF_SIZE = 4096;
+
+    private FinishableOutputStream out;
+    private final DeltaEncoder delta;
+    private final byte[] filterBuf = new byte[FILTER_BUF_SIZE];
+
+    private boolean finished = false;
+    private IOException exception = null;
+
+    private final byte[] tempBuf = new byte[1];
+
+    static int getMemoryUsage() {
+        return 1 + FILTER_BUF_SIZE / 1024;
+    }
+
+    DeltaOutputStream(FinishableOutputStream out, DeltaOptions options) {
+        this.out = out;
+        delta = new DeltaEncoder(options.getDistance());
+    }
+
+    public void write(int b) throws IOException {
+        tempBuf[0] = (byte)b;
+        write(tempBuf, 0, 1);
+    }
+
+    public void write(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished");
+
+        try {
+            while (len > FILTER_BUF_SIZE) {
+                delta.encode(buf, off, FILTER_BUF_SIZE, filterBuf);
+                out.write(filterBuf);
+                off += FILTER_BUF_SIZE;
+                len -= FILTER_BUF_SIZE;
+            }
+
+            delta.encode(buf, off, len, filterBuf);
+            out.write(filterBuf, 0, len);
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    public void flush() throws IOException {
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        try {
+            out.flush();
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    public void finish() throws IOException {
+        if (!finished) {
+            if (exception != null)
+                throw exception;
+
+            try {
+                out.finish();
+            } catch (IOException e) {
+                exception = e;
+                throw e;
+            }
+
+            finished = true;
+        }
+    }
+
+    public void close() throws IOException {
+        if (out != null) {
+            try {
+                out.close();
+            } catch (IOException e) {
+                if (exception == null)
+                    exception = e;
+            }
+
+            out = null;
+        }
+
+        if (exception != null)
+            throw exception;
+    }
+}

app/src/main/java/org/tukaani/xz/FilterCoder.java

@@ -0,0 +1,16 @@
+/*
+ * FilterCoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+interface FilterCoder {
+    boolean changesSize();
+    boolean nonLastOK();
+    boolean lastOK();
+}

app/src/main/java/org/tukaani/xz/FilterDecoder.java

@@ -0,0 +1,17 @@
+/*
+ * FilterDecoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+
+interface FilterDecoder extends FilterCoder {
+    int getMemoryUsage();
+    InputStream getInputStream(InputStream in, ArrayCache arrayCache);
+}

app/src/main/java/org/tukaani/xz/FilterEncoder.java

@@ -0,0 +1,18 @@
+/*
+ * FilterEncoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+interface FilterEncoder extends FilterCoder {
+    long getFilterID();
+    byte[] getFilterProps();
+    boolean supportsFlushing();
+    FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                           ArrayCache arrayCache);
+}

app/src/main/java/org/tukaani/xz/FilterOptions.java

@@ -0,0 +1,104 @@
+/*
+ * FilterOptions
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.IOException;
+
+/**
+ * Base class for filter-specific options classes.
+ */
+public abstract class FilterOptions implements Cloneable {
+    /**
+     * Gets how much memory the encoder will need with
+     * the given filter chain. This function simply calls
+     * <code>getEncoderMemoryUsage()</code> for every filter
+     * in the array and returns the sum of the returned values.
+     */
+    public static int getEncoderMemoryUsage(FilterOptions[] options) {
+        int m = 0;
+
+        for (int i = 0; i < options.length; ++i)
+            m += options[i].getEncoderMemoryUsage();
+
+        return m;
+    }
+
+    /**
+     * Gets how much memory the decoder will need with
+     * the given filter chain. This function simply calls
+     * <code>getDecoderMemoryUsage()</code> for every filter
+     * in the array and returns the sum of the returned values.
+     */
+    public static int getDecoderMemoryUsage(FilterOptions[] options) {
+        int m = 0;
+
+        for (int i = 0; i < options.length; ++i)
+            m += options[i].getDecoderMemoryUsage();
+
+        return m;
+    }
+
+    /**
+     * Gets how much memory the encoder will need with these options.
+     */
+    public abstract int getEncoderMemoryUsage();
+
+    /**
+     * Gets a raw (no XZ headers) encoder output stream using these options.
+     * Raw streams are an advanced feature. In most cases you want to store
+     * the compressed data in the .xz container format instead of using
+     * a raw stream. To use this filter in a .xz file, pass this object
+     * to XZOutputStream.
+     * <p>
+     * This is uses ArrayCache.getDefaultCache() as the ArrayCache.
+     */
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out) {
+        return getOutputStream(out, ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Gets a raw (no XZ headers) encoder output stream using these options
+     * and the given ArrayCache.
+     * Raw streams are an advanced feature. In most cases you want to store
+     * the compressed data in the .xz container format instead of using
+     * a raw stream. To use this filter in a .xz file, pass this object
+     * to XZOutputStream.
+     */
+    public abstract FinishableOutputStream getOutputStream(
+            FinishableOutputStream out, ArrayCache arrayCache);
+
+    /**
+     * Gets how much memory the decoder will need to decompress the data
+     * that was encoded with these options.
+     */
+    public abstract int getDecoderMemoryUsage();
+
+    /**
+     * Gets a raw (no XZ headers) decoder input stream using these options.
+     * <p>
+     * This is uses ArrayCache.getDefaultCache() as the ArrayCache.
+     */
+    public InputStream getInputStream(InputStream in) throws IOException {
+        return getInputStream(in, ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Gets a raw (no XZ headers) decoder input stream using these options
+     * and the given ArrayCache.
+     */
+    public abstract InputStream getInputStream(
+            InputStream in, ArrayCache arrayCache) throws IOException;
+
+    abstract FilterEncoder getFilterEncoder();
+
+    FilterOptions() {}
+}

app/src/main/java/org/tukaani/xz/FinishableOutputStream.java

@@ -0,0 +1,31 @@
+/*
+ * FinishableOutputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.OutputStream;
+import java.io.IOException;
+
+/**
+ * Output stream that supports finishing without closing
+ * the underlying stream.
+ */
+public abstract class FinishableOutputStream extends OutputStream {
+    /**
+     * Finish the stream without closing the underlying stream.
+     * No more data may be written to the stream after finishing.
+     * <p>
+     * The <code>finish</code> method of <code>FinishableOutputStream</code>
+     * does nothing. Subclasses should override it if they need finishing
+     * support, which is the case, for example, with compressors.
+     *
+     * @throws      IOException
+     */
+    public void finish() throws IOException {}
+}

app/src/main/java/org/tukaani/xz/FinishableWrapperOutputStream.java

@@ -0,0 +1,70 @@
+/*
+ * FinishableWrapperOutputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.OutputStream;
+import java.io.IOException;
+
+/**
+ * Wraps an output stream to a finishable output stream for use with
+ * raw encoders. This is not needed for XZ compression and thus most
+ * people will never need this.
+ */
+public class FinishableWrapperOutputStream extends FinishableOutputStream {
+    /**
+     * The {@link java.io.OutputStream OutputStream} that has been
+     * wrapped into a FinishableWrapperOutputStream.
+     */
+    protected OutputStream out;
+
+    /**
+     * Creates a new output stream which support finishing.
+     * The <code>finish()</code> method will do nothing.
+     */
+    public FinishableWrapperOutputStream(OutputStream out) {
+        this.out = out;
+    }
+
+    /**
+     * Calls {@link java.io.OutputStream#write(int) out.write(b)}.
+     */
+    public void write(int b) throws IOException {
+        out.write(b);
+    }
+
+    /**
+     * Calls {@link java.io.OutputStream#write(byte[]) out.write(buf)}.
+     */
+    public void write(byte[] buf) throws IOException {
+        out.write(buf);
+    }
+
+    /**
+     * Calls {@link java.io.OutputStream#write(byte[],int,int)
+                    out.write(buf, off, len)}.
+     */
+    public void write(byte[] buf, int off, int len) throws IOException {
+        out.write(buf, off, len);
+    }
+
+    /**
+     * Calls {@link java.io.OutputStream#flush() out.flush()}.
+     */
+    public void flush() throws IOException {
+        out.flush();
+    }
+
+    /**
+     * Calls {@link java.io.OutputStream#close() out.close()}.
+     */
+    public void close() throws IOException {
+        out.close();
+    }
+}

app/src/main/java/org/tukaani/xz/IA64Options.java

@@ -0,0 +1,37 @@
+/*
+ * IA64Options
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import org.tukaani.xz.simple.IA64;
+
+/**
+ * BCJ filter for Itanium (IA-64) instructions.
+ */
+public class IA64Options extends BCJOptions {
+    private static final int ALIGNMENT = 16;
+
+    public IA64Options() {
+        super(ALIGNMENT);
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return new SimpleOutputStream(out, new IA64(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        return new SimpleInputStream(in, new IA64(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.IA64_FILTER_ID);
+    }
+}

app/src/main/java/org/tukaani/xz/IndexIndicatorException.java

@@ -0,0 +1,14 @@
+/*
+ * IndexIndicatorException
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+class IndexIndicatorException extends Exception {
+    private static final long serialVersionUID = 1L;
+}

app/src/main/java/org/tukaani/xz/LZMA2Coder.java

@@ -0,0 +1,26 @@
+/*
+ * LZMA2Coder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+abstract class LZMA2Coder implements FilterCoder {
+    public static final long FILTER_ID = 0x21;
+
+    public boolean changesSize() {
+        return true;
+    }
+
+    public boolean nonLastOK() {
+        return false;
+    }
+
+    public boolean lastOK() {
+        return true;
+    }
+}

app/src/main/java/org/tukaani/xz/LZMA2Decoder.java

@@ -0,0 +1,35 @@
+/*
+ * LZMA2Decoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+
+class LZMA2Decoder extends LZMA2Coder implements FilterDecoder {
+    private int dictSize;
+
+    LZMA2Decoder(byte[] props) throws UnsupportedOptionsException {
+        // Up to 1.5 GiB dictionary is supported. The bigger ones
+        // are too big for int.
+        if (props.length != 1 || (props[0] & 0xFF) > 37)
+            throw new UnsupportedOptionsException(
+                    "Unsupported LZMA2 properties");
+
+        dictSize = 2 | (props[0] & 1);
+        dictSize <<= (props[0] >>> 1) + 11;
+    }
+
+    public int getMemoryUsage() {
+        return LZMA2InputStream.getMemoryUsage(dictSize);
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        return new LZMA2InputStream(in, dictSize, null, arrayCache);
+    }
+}

app/src/main/java/org/tukaani/xz/LZMA2Encoder.java

@@ -0,0 +1,51 @@
+/*
+ * LZMA2Encoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import org.tukaani.xz.lzma.LZMAEncoder;
+
+class LZMA2Encoder extends LZMA2Coder implements FilterEncoder {
+    private final LZMA2Options options;
+    private final byte[] props = new byte[1];
+
+    LZMA2Encoder(LZMA2Options options) {
+        if (options.getPresetDict() != null)
+            throw new IllegalArgumentException(
+                    "XZ doesn't support a preset dictionary for now");
+
+        if (options.getMode() == LZMA2Options.MODE_UNCOMPRESSED) {
+            props[0] = (byte)0;
+        } else {
+            int d = Math.max(options.getDictSize(),
+                             LZMA2Options.DICT_SIZE_MIN);
+            props[0] = (byte)(LZMAEncoder.getDistSlot(d - 1) - 23);
+        }
+
+        // Make a private copy so that the caller is free to change its copy.
+        this.options = (LZMA2Options)options.clone();
+    }
+
+    public long getFilterID() {
+        return FILTER_ID;
+    }
+
+    public byte[] getFilterProps() {
+        return props;
+    }
+
+    public boolean supportsFlushing() {
+        return true;
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return options.getOutputStream(out, arrayCache);
+    }
+}

app/src/main/java/org/tukaani/xz/LZMA2InputStream.java

@@ -0,0 +1,401 @@
+/*
+ * LZMA2InputStream
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.EOFException;
+import org.tukaani.xz.lz.LZDecoder;
+import org.tukaani.xz.rangecoder.RangeDecoderFromBuffer;
+import org.tukaani.xz.lzma.LZMADecoder;
+
+/**
+ * Decompresses a raw LZMA2 stream (no XZ headers).
+ */
+public class LZMA2InputStream extends InputStream {
+    /**
+     * Smallest valid LZMA2 dictionary size.
+     * <p>
+     * Very tiny dictionaries would be a performance problem, so
+     * the minimum is 4 KiB.
+     */
+    public static final int DICT_SIZE_MIN = 4096;
+
+    /**
+     * Largest dictionary size supported by this implementation.
+     * <p>
+     * The LZMA2 algorithm allows dictionaries up to one byte less than 4 GiB.
+     * This implementation supports only 16 bytes less than 2 GiB for raw
+     * LZMA2 streams, and for .xz files the maximum is 1.5 GiB. This
+     * limitation is due to Java using signed 32-bit integers for array
+     * indexing. The limitation shouldn't matter much in practice since so
+     * huge dictionaries are not normally used.
+     */
+    public static final int DICT_SIZE_MAX = Integer.MAX_VALUE & ~15;
+
+    private static final int COMPRESSED_SIZE_MAX = 1 << 16;
+
+    private final ArrayCache arrayCache;
+    private DataInputStream in;
+
+    private LZDecoder lz;
+    private RangeDecoderFromBuffer rc;
+    private LZMADecoder lzma;
+
+    private int uncompressedSize = 0;
+    private boolean isLZMAChunk = false;
+
+    private boolean needDictReset = true;
+    private boolean needProps = true;
+    private boolean endReached = false;
+
+    private IOException exception = null;
+
+    private final byte[] tempBuf = new byte[1];
+
+    /**
+     * Gets approximate decompressor memory requirements as kibibytes for
+     * the given dictionary size.
+     *
+     * @param       dictSize    LZMA2 dictionary size as bytes, must be
+     *                          in the range [<code>DICT_SIZE_MIN</code>,
+     *                          <code>DICT_SIZE_MAX</code>]
+     *
+     * @return      approximate memory requirements as kibibytes (KiB)
+     */
+    public static int getMemoryUsage(int dictSize) {
+        // The base state is around 30-40 KiB (probabilities etc.),
+        // range decoder needs COMPRESSED_SIZE_MAX bytes for buffering,
+        // and LZ decoder needs a dictionary buffer.
+        return 40 + COMPRESSED_SIZE_MAX / 1024 + getDictSize(dictSize) / 1024;
+    }
+
+    private static int getDictSize(int dictSize) {
+        if (dictSize < DICT_SIZE_MIN || dictSize > DICT_SIZE_MAX)
+            throw new IllegalArgumentException(
+                    "Unsupported dictionary size " + dictSize);
+
+        // Round dictionary size upward to a multiple of 16. This way LZMA
+        // can use LZDecoder.getPos() for calculating LZMA's posMask.
+        // Note that this check is needed only for raw LZMA2 streams; it is
+        // redundant with .xz.
+        return (dictSize + 15) & ~15;
+    }
+
+    /**
+     * Creates a new input stream that decompresses raw LZMA2 data
+     * from <code>in</code>.
+     * <p>
+     * The caller needs to know the dictionary size used when compressing;
+     * the dictionary size isn't stored as part of a raw LZMA2 stream.
+     * <p>
+     * Specifying a too small dictionary size will prevent decompressing
+     * the stream. Specifying a too big dictionary is waste of memory but
+     * decompression will work.
+     * <p>
+     * There is no need to specify a dictionary bigger than
+     * the uncompressed size of the data even if a bigger dictionary
+     * was used when compressing. If you know the uncompressed size
+     * of the data, this might allow saving some memory.
+     *
+     * @param       in          input stream from which LZMA2-compressed
+     *                          data is read
+     *
+     * @param       dictSize    LZMA2 dictionary size as bytes, must be
+     *                          in the range [<code>DICT_SIZE_MIN</code>,
+     *                          <code>DICT_SIZE_MAX</code>]
+     */
+    public LZMA2InputStream(InputStream in, int dictSize) {
+        this(in, dictSize, null);
+    }
+
+    /**
+     * Creates a new LZMA2 decompressor using a preset dictionary.
+     * <p>
+     * This is like <code>LZMA2InputStream(InputStream, int)</code> except
+     * that the dictionary may be initialized using a preset dictionary.
+     * If a preset dictionary was used when compressing the data, the
+     * same preset dictionary must be provided when decompressing.
+     *
+     * @param       in          input stream from which LZMA2-compressed
+     *                          data is read
+     *
+     * @param       dictSize    LZMA2 dictionary size as bytes, must be
+     *                          in the range [<code>DICT_SIZE_MIN</code>,
+     *                          <code>DICT_SIZE_MAX</code>]
+     *
+     * @param       presetDict  preset dictionary or <code>null</code>
+     *                          to use no preset dictionary
+     */
+    public LZMA2InputStream(InputStream in, int dictSize, byte[] presetDict) {
+        this(in, dictSize, presetDict, ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new LZMA2 decompressor using a preset dictionary
+     * and array cache.
+     * <p>
+     * This is like <code>LZMA2InputStream(InputStream, int, byte[])</code>
+     * except that this also takes the <code>arrayCache</code> argument.
+     *
+     * @param       in          input stream from which LZMA2-compressed
+     *                          data is read
+     *
+     * @param       dictSize    LZMA2 dictionary size as bytes, must be
+     *                          in the range [<code>DICT_SIZE_MIN</code>,
+     *                          <code>DICT_SIZE_MAX</code>]
+     *
+     * @param       presetDict  preset dictionary or <code>null</code>
+     *                          to use no preset dictionary
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @since 1.7
+     */
+    LZMA2InputStream(InputStream in, int dictSize, byte[] presetDict,
+                     ArrayCache arrayCache) {
+        // Check for null because otherwise null isn't detect
+        // in this constructor.
+        if (in == null)
+            throw new NullPointerException();
+
+        this.arrayCache = arrayCache;
+        this.in = new DataInputStream(in);
+        this.rc = new RangeDecoderFromBuffer(COMPRESSED_SIZE_MAX, arrayCache);
+        this.lz = new LZDecoder(getDictSize(dictSize), presetDict, arrayCache);
+
+        if (presetDict != null && presetDict.length > 0)
+            needDictReset = false;
+    }
+
+    /**
+     * Decompresses the next byte from this input stream.
+     * <p>
+     * Reading lots of data with <code>read()</code> from this input stream
+     * may be inefficient. Wrap it in <code>java.io.BufferedInputStream</code>
+     * if you need to read lots of data one byte at a time.
+     *
+     * @return      the next decompressed byte, or <code>-1</code>
+     *              to indicate the end of the compressed stream
+     *
+     * @throws      CorruptedInputException
+     *
+     * @throws      XZIOException if the stream has been closed
+     *
+     * @throws      EOFException
+     *                          compressed input is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public int read() throws IOException {
+        return read(tempBuf, 0, 1) == -1 ? -1 : (tempBuf[0] & 0xFF);
+    }
+
+    /**
+     * Decompresses into an array of bytes.
+     * <p>
+     * If <code>len</code> is zero, no bytes are read and <code>0</code>
+     * is returned. Otherwise this will block until <code>len</code>
+     * bytes have been decompressed, the end of the LZMA2 stream is reached,
+     * or an exception is thrown.
+     *
+     * @param       buf         target buffer for uncompressed data
+     * @param       off         start offset in <code>buf</code>
+     * @param       len         maximum number of uncompressed bytes to read
+     *
+     * @return      number of bytes read, or <code>-1</code> to indicate
+     *              the end of the compressed stream
+     *
+     * @throws      CorruptedInputException
+     *
+     * @throws      XZIOException if the stream has been closed
+     *
+     * @throws      EOFException
+     *                          compressed input is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public int read(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (len == 0)
+            return 0;
+
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        if (endReached)
+            return -1;
+
+        try {
+            int size = 0;
+
+            while (len > 0) {
+                if (uncompressedSize == 0) {
+                    decodeChunkHeader();
+                    if (endReached)
+                        return size == 0 ? -1 : size;
+                }
+
+                int copySizeMax = Math.min(uncompressedSize, len);
+
+                if (!isLZMAChunk) {
+                    lz.copyUncompressed(in, copySizeMax);
+                } else {
+                    lz.setLimit(copySizeMax);
+                    lzma.decode();
+                }
+
+                int copiedSize = lz.flush(buf, off);
+                off += copiedSize;
+                len -= copiedSize;
+                size += copiedSize;
+                uncompressedSize -= copiedSize;
+
+                if (uncompressedSize == 0)
+                    if (!rc.isFinished() || lz.hasPending())
+                        throw new CorruptedInputException();
+            }
+
+            return size;
+
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    private void decodeChunkHeader() throws IOException {
+        int control = in.readUnsignedByte();
+
+        if (control == 0x00) {
+            endReached = true;
+            putArraysToCache();
+            return;
+        }
+
+        if (control >= 0xE0 || control == 0x01) {
+            needProps = true;
+            needDictReset = false;
+            lz.reset();
+        } else if (needDictReset) {
+            throw new CorruptedInputException();
+        }
+
+        if (control >= 0x80) {
+            isLZMAChunk = true;
+
+            uncompressedSize = (control & 0x1F) << 16;
+            uncompressedSize += in.readUnsignedShort() + 1;
+
+            int compressedSize = in.readUnsignedShort() + 1;
+
+            if (control >= 0xC0) {
+                needProps = false;
+                decodeProps();
+
+            } else if (needProps) {
+                throw new CorruptedInputException();
+
+            } else if (control >= 0xA0) {
+                lzma.reset();
+            }
+
+            rc.prepareInputBuffer(in, compressedSize);
+
+        } else if (control > 0x02) {
+            throw new CorruptedInputException();
+
+        } else {
+            isLZMAChunk = false;
+            uncompressedSize = in.readUnsignedShort() + 1;
+        }
+    }
+
+    private void decodeProps() throws IOException {
+        int props = in.readUnsignedByte();
+
+        if (props > (4 * 5 + 4) * 9 + 8)
+            throw new CorruptedInputException();
+
+        int pb = props / (9 * 5);
+        props -= pb * 9 * 5;
+        int lp = props / 9;
+        int lc = props - lp * 9;
+
+        if (lc + lp > 4)
+            throw new CorruptedInputException();
+
+        lzma = new LZMADecoder(lz, rc, lc, lp, pb);
+    }
+
+    /**
+     * Returns the number of uncompressed bytes that can be read
+     * without blocking. The value is returned with an assumption
+     * that the compressed input data will be valid. If the compressed
+     * data is corrupt, <code>CorruptedInputException</code> may get
+     * thrown before the number of bytes claimed to be available have
+     * been read from this input stream.
+     * <p>
+     * In LZMA2InputStream, the return value will be non-zero when the
+     * decompressor is in the middle of an LZMA2 chunk. The return value
+     * will then be the number of uncompressed bytes remaining from that
+     * chunk. The return value can also be non-zero in the middle of
+     * an uncompressed chunk, but then the return value depends also on
+     * the <code>available()</code> method of the underlying InputStream.
+     *
+     * @return      the number of uncompressed bytes that can be read
+     *              without blocking
+     */
+    public int available() throws IOException {
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        return isLZMAChunk ? uncompressedSize
+                           : Math.min(uncompressedSize, in.available());
+    }
+
+    private void putArraysToCache() {
+        if (lz != null) {
+            lz.putArraysToCache(arrayCache);
+            lz = null;
+
+            rc.putArraysToCache(arrayCache);
+            rc = null;
+        }
+    }
+
+    /**
+     * Closes the stream and calls <code>in.close()</code>.
+     * If the stream was already closed, this does nothing.
+     *
+     * @throws  IOException if thrown by <code>in.close()</code>
+     */
+    public void close() throws IOException {
+        if (in != null) {
+            putArraysToCache();
+
+            try {
+                in.close();
+            } finally {
+                in = null;
+            }
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/LZMA2Options.java

@@ -0,0 +1,583 @@
+/*
+ * LZMA2Options
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.IOException;
+import org.tukaani.xz.lz.LZEncoder;
+import org.tukaani.xz.lzma.LZMAEncoder;
+
+/**
+ * LZMA2 compression options.
+ * <p>
+ * While this allows setting the LZMA2 compression options in detail,
+ * often you only need <code>LZMA2Options()</code> or
+ * <code>LZMA2Options(int)</code>.
+ */
+public class LZMA2Options extends FilterOptions {
+    /**
+     * Minimum valid compression preset level is 0.
+     */
+    public static final int PRESET_MIN = 0;
+
+    /**
+     * Maximum valid compression preset level is 9.
+     */
+    public static final int PRESET_MAX = 9;
+
+    /**
+     * Default compression preset level is 6.
+     */
+    public static final int PRESET_DEFAULT = 6;
+
+    /**
+     * Minimum dictionary size is 4 KiB.
+     */
+    public static final int DICT_SIZE_MIN = 4096;
+
+    /**
+     * Maximum dictionary size for compression is 768 MiB.
+     * <p>
+     * The decompressor supports bigger dictionaries, up to almost 2 GiB.
+     * With HC4 the encoder would support dictionaries bigger than 768 MiB.
+     * The 768 MiB limit comes from the current implementation of BT4 where
+     * we would otherwise hit the limits of signed ints in array indexing.
+     * <p>
+     * If you really need bigger dictionary for decompression,
+     * use {@link LZMA2InputStream} directly.
+     */
+    public static final int DICT_SIZE_MAX = 768 << 20;
+
+    /**
+     * The default dictionary size is 8 MiB.
+     */
+    public static final int DICT_SIZE_DEFAULT = 8 << 20;
+
+    /**
+     * Maximum value for lc + lp is 4.
+     */
+    public static final int LC_LP_MAX = 4;
+
+    /**
+     * The default number of literal context bits is 3.
+     */
+    public static final int LC_DEFAULT = 3;
+
+    /**
+     * The default number of literal position bits is 0.
+     */
+    public static final int LP_DEFAULT = 0;
+
+    /**
+     * Maximum value for pb is 4.
+     */
+    public static final int PB_MAX = 4;
+
+    /**
+     * The default number of position bits is 2.
+     */
+    public static final int PB_DEFAULT = 2;
+
+    /**
+     * Compression mode: uncompressed.
+     * The data is wrapped into a LZMA2 stream without compression.
+     */
+    public static final int MODE_UNCOMPRESSED = 0;
+
+    /**
+     * Compression mode: fast.
+     * This is usually combined with a hash chain match finder.
+     */
+    public static final int MODE_FAST = LZMAEncoder.MODE_FAST;
+
+    /**
+     * Compression mode: normal.
+     * This is usually combined with a binary tree match finder.
+     */
+    public static final int MODE_NORMAL = LZMAEncoder.MODE_NORMAL;
+
+    /**
+     * Minimum value for <code>niceLen</code> is 8.
+     */
+    public static final int NICE_LEN_MIN = 8;
+
+    /**
+     * Maximum value for <code>niceLen</code> is 273.
+     */
+    public static final int NICE_LEN_MAX = 273;
+
+    /**
+     * Match finder: Hash Chain 2-3-4
+     */
+    public static final int MF_HC4 = LZEncoder.MF_HC4;
+
+    /**
+     * Match finder: Binary tree 2-3-4
+     */
+    public static final int MF_BT4 = LZEncoder.MF_BT4;
+
+    private static final int[] presetToDictSize = {
+            1 << 18, 1 << 20, 1 << 21, 1 << 22, 1 << 22,
+            1 << 23, 1 << 23, 1 << 24, 1 << 25, 1 << 26 };
+
+    private static final int[] presetToDepthLimit = { 4, 8, 24, 48 };
+
+    private int dictSize;
+    private byte[] presetDict = null;
+    private int lc;
+    private int lp;
+    private int pb;
+    private int mode;
+    private int niceLen;
+    private int mf;
+    private int depthLimit;
+
+    /**
+     * Creates new LZMA2 options and sets them to the default values.
+     * This is equivalent to <code>LZMA2Options(PRESET_DEFAULT)</code>.
+     */
+    public LZMA2Options() {
+        try {
+            setPreset(PRESET_DEFAULT);
+        } catch (UnsupportedOptionsException e) {
+            assert false;
+            throw new RuntimeException();
+        }
+    }
+
+    /**
+     * Creates new LZMA2 options and sets them to the given preset.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>preset</code> is not supported
+     */
+    public LZMA2Options(int preset) throws UnsupportedOptionsException {
+        setPreset(preset);
+    }
+
+    /**
+     * Creates new LZMA2 options and sets them to the given custom values.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          unsupported options were specified
+     */
+    public LZMA2Options(int dictSize, int lc, int lp, int pb, int mode,
+                        int niceLen, int mf, int depthLimit)
+            throws UnsupportedOptionsException {
+        setDictSize(dictSize);
+        setLcLp(lc, lp);
+        setPb(pb);
+        setMode(mode);
+        setNiceLen(niceLen);
+        setMatchFinder(mf);
+        setDepthLimit(depthLimit);
+    }
+
+    /**
+     * Sets the compression options to the given preset.
+     * <p>
+     * The presets 0-3 are fast presets with medium compression.
+     * The presets 4-6 are fairly slow presets with high compression.
+     * The default preset (<code>PRESET_DEFAULT</code>) is 6.
+     * <p>
+     * The presets 7-9 are like the preset 6 but use bigger dictionaries
+     * and have higher compressor and decompressor memory requirements.
+     * Unless the uncompressed size of the file exceeds 8&nbsp;MiB,
+     * 16&nbsp;MiB, or 32&nbsp;MiB, it is waste of memory to use the
+     * presets 7, 8, or 9, respectively.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>preset</code> is not supported
+     */
+    public void setPreset(int preset) throws UnsupportedOptionsException {
+        if (preset < 0 || preset > 9)
+            throw new UnsupportedOptionsException(
+                    "Unsupported preset: " + preset);
+
+        lc = LC_DEFAULT;
+        lp = LP_DEFAULT;
+        pb = PB_DEFAULT;
+        dictSize = presetToDictSize[preset];
+
+        if (preset <= 3) {
+            mode = MODE_FAST;
+            mf = MF_HC4;
+            niceLen = preset <= 1 ? 128 : NICE_LEN_MAX;
+            depthLimit = presetToDepthLimit[preset];
+        } else {
+            mode = MODE_NORMAL;
+            mf = MF_BT4;
+            niceLen = (preset == 4) ? 16 : (preset == 5) ? 32 : 64;
+            depthLimit = 0;
+        }
+    }
+
+    /**
+     * Sets the dictionary size in bytes.
+     * <p>
+     * The dictionary (or history buffer) holds the most recently seen
+     * uncompressed data. Bigger dictionary usually means better compression.
+     * However, using a dictioanary bigger than the size of the uncompressed
+     * data is waste of memory.
+     * <p>
+     * Any value in the range [DICT_SIZE_MIN, DICT_SIZE_MAX] is valid,
+     * but sizes of 2^n and 2^n&nbsp;+&nbsp;2^(n-1) bytes are somewhat
+     * recommended.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>dictSize</code> is not supported
+     */
+    public void setDictSize(int dictSize) throws UnsupportedOptionsException {
+        if (dictSize < DICT_SIZE_MIN)
+            throw new UnsupportedOptionsException(
+                    "LZMA2 dictionary size must be at least 4 KiB: "
+                    + dictSize + " B");
+
+        if (dictSize > DICT_SIZE_MAX)
+            throw new UnsupportedOptionsException(
+                    "LZMA2 dictionary size must not exceed "
+                    + (DICT_SIZE_MAX >> 20) + " MiB: " + dictSize + " B");
+
+        this.dictSize = dictSize;
+    }
+
+    /**
+     * Gets the dictionary size in bytes.
+     */
+    public int getDictSize() {
+        return dictSize;
+    }
+
+    /**
+     * Sets a preset dictionary. Use null to disable the use of
+     * a preset dictionary. By default there is no preset dictionary.
+     * <p>
+     * <b>The .xz format doesn't support a preset dictionary for now.
+     * Do not set a preset dictionary unless you use raw LZMA2.</b>
+     * <p>
+     * Preset dictionary can be useful when compressing many similar,
+     * relatively small chunks of data independently from each other.
+     * A preset dictionary should contain typical strings that occur in
+     * the files being compressed. The most probable strings should be
+     * near the end of the preset dictionary. The preset dictionary used
+     * for compression is also needed for decompression.
+     */
+    public void setPresetDict(byte[] presetDict) {
+        this.presetDict = presetDict;
+    }
+
+    /**
+     * Gets the preset dictionary.
+     */
+    public byte[] getPresetDict() {
+        return presetDict;
+    }
+
+    /**
+     * Sets the number of literal context bits and literal position bits.
+     * <p>
+     * The sum of <code>lc</code> and <code>lp</code> is limited to 4.
+     * Trying to exceed it will throw an exception. This function lets
+     * you change both at the same time.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>lc</code> and <code>lp</code>
+     *                          are invalid
+     */
+    public void setLcLp(int lc, int lp) throws UnsupportedOptionsException {
+        if (lc < 0 || lp < 0 || lc > LC_LP_MAX || lp > LC_LP_MAX
+                || lc + lp > LC_LP_MAX)
+            throw new UnsupportedOptionsException(
+                    "lc + lp must not exceed " + LC_LP_MAX + ": "
+                    + lc + " + " + lp);
+
+        this.lc = lc;
+        this.lp = lp;
+    }
+
+    /**
+     * Sets the number of literal context bits.
+     * <p>
+     * All bytes that cannot be encoded as matches are encoded as literals.
+     * That is, literals are simply 8-bit bytes that are encoded one at
+     * a time.
+     * <p>
+     * The literal coding makes an assumption that the highest <code>lc</code>
+     * bits of the previous uncompressed byte correlate with the next byte.
+     * For example, in typical English text, an upper-case letter is often
+     * followed by a lower-case letter, and a lower-case letter is usually
+     * followed by another lower-case letter. In the US-ASCII character set,
+     * the highest three bits are 010 for upper-case letters and 011 for
+     * lower-case letters. When <code>lc</code> is at least 3, the literal
+     * coding can take advantage of this property in the  uncompressed data.
+     * <p>
+     * The default value (3) is usually good. If you want maximum compression,
+     * try <code>setLc(4)</code>. Sometimes it helps a little, and sometimes it
+     * makes compression worse. If it makes it worse, test for example
+     * <code>setLc(2)</code> too.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>lc</code> is invalid, or the sum
+     *                          of <code>lc</code> and <code>lp</code>
+     *                          exceed LC_LP_MAX
+     */
+    public void setLc(int lc) throws UnsupportedOptionsException {
+        setLcLp(lc, lp);
+    }
+
+    /**
+     * Sets the number of literal position bits.
+     * <p>
+     * This affets what kind of alignment in the uncompressed data is
+     * assumed when encoding literals. See {@link #setPb(int) setPb} for
+     * more information about alignment.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>lp</code> is invalid, or the sum
+     *                          of <code>lc</code> and <code>lp</code>
+     *                          exceed LC_LP_MAX
+     */
+    public void setLp(int lp) throws UnsupportedOptionsException {
+        setLcLp(lc, lp);
+    }
+
+    /**
+     * Gets the number of literal context bits.
+     */
+    public int getLc() {
+        return lc;
+    }
+
+    /**
+     * Gets the number of literal position bits.
+     */
+    public int getLp() {
+        return lp;
+    }
+
+    /**
+     * Sets the number of position bits.
+     * <p>
+     * This affects what kind of alignment in the uncompressed data is
+     * assumed in general. The default (2) means four-byte alignment
+     * (2^<code>pb</code> = 2^2 = 4), which is often a good choice when
+     * there's no better guess.
+     * <p>
+     * When the alignment is known, setting the number of position bits
+     * accordingly may reduce the file size a little. For example with text
+     * files having one-byte alignment (US-ASCII, ISO-8859-*, UTF-8), using
+     * <code>setPb(0)</code> can improve compression slightly. For UTF-16
+     * text, <code>setPb(1)</code> is a good choice. If the alignment is
+     * an odd number like 3 bytes, <code>setPb(0)</code> might be the best
+     * choice.
+     * <p>
+     * Even though the assumed alignment can be adjusted with
+     * <code>setPb</code> and <code>setLp</code>, LZMA2 still slightly favors
+     * 16-byte alignment. It might be worth taking into account when designing
+     * file formats that are likely to be often compressed with LZMA2.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>pb</code> is invalid
+     */
+    public void setPb(int pb) throws UnsupportedOptionsException {
+        if (pb < 0 || pb > PB_MAX)
+            throw new UnsupportedOptionsException(
+                    "pb must not exceed " + PB_MAX + ": " + pb);
+
+        this.pb = pb;
+    }
+
+    /**
+     * Gets the number of position bits.
+     */
+    public int getPb() {
+        return pb;
+    }
+
+    /**
+     * Sets the compression mode.
+     * <p>
+     * This specifies the method to analyze the data produced by
+     * a match finder. The default is <code>MODE_FAST</code> for presets
+     * 0-3 and <code>MODE_NORMAL</code> for presets 4-9.
+     * <p>
+     * Usually <code>MODE_FAST</code> is used with Hash Chain match finders
+     * and <code>MODE_NORMAL</code> with Binary Tree match finders. This is
+     * also what the presets do.
+     * <p>
+     * The special mode <code>MODE_UNCOMPRESSED</code> doesn't try to
+     * compress the data at all (and doesn't use a match finder) and will
+     * simply wrap it in uncompressed LZMA2 chunks.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>mode</code> is not supported
+     */
+    public void setMode(int mode) throws UnsupportedOptionsException {
+        if (mode < MODE_UNCOMPRESSED || mode > MODE_NORMAL)
+            throw new UnsupportedOptionsException(
+                    "Unsupported compression mode: " + mode);
+
+        this.mode = mode;
+    }
+
+    /**
+     * Gets the compression mode.
+     */
+    public int getMode() {
+        return mode;
+    }
+
+    /**
+     * Sets the nice length of matches.
+     * Once a match of at least <code>niceLen</code> bytes is found,
+     * the algorithm stops looking for better matches. Higher values tend
+     * to give better compression at the expense of speed. The default
+     * depends on the preset.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>niceLen</code> is invalid
+     */
+    public void setNiceLen(int niceLen) throws UnsupportedOptionsException {
+        if (niceLen < NICE_LEN_MIN)
+            throw new UnsupportedOptionsException(
+                    "Minimum nice length of matches is "
+                    + NICE_LEN_MIN + " bytes: " + niceLen);
+
+        if (niceLen > NICE_LEN_MAX)
+            throw new UnsupportedOptionsException(
+                    "Maximum nice length of matches is " + NICE_LEN_MAX
+                    + ": " + niceLen);
+
+        this.niceLen = niceLen;
+    }
+
+    /**
+     * Gets the nice length of matches.
+     */
+    public int getNiceLen() {
+        return niceLen;
+    }
+
+    /**
+     * Sets the match finder type.
+     * <p>
+     * Match finder has a major effect on compression speed, memory usage,
+     * and compression ratio. Usually Hash Chain match finders are faster
+     * than Binary Tree match finders. The default depends on the preset:
+     * 0-3 use <code>MF_HC4</code> and 4-9 use <code>MF_BT4</code>.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>mf</code> is not supported
+     */
+    public void setMatchFinder(int mf) throws UnsupportedOptionsException {
+        if (mf != MF_HC4 && mf != MF_BT4)
+            throw new UnsupportedOptionsException(
+                    "Unsupported match finder: " + mf);
+
+        this.mf = mf;
+    }
+
+    /**
+     * Gets the match finder type.
+     */
+    public int getMatchFinder() {
+        return mf;
+    }
+
+    /**
+     * Sets the match finder search depth limit.
+     * <p>
+     * The default is a special value of <code>0</code> which indicates that
+     * the depth limit should be automatically calculated by the selected
+     * match finder from the nice length of matches.
+     * <p>
+     * Reasonable depth limit for Hash Chain match finders is 4-100 and
+     * 16-1000 for Binary Tree match finders. Using very high values can
+     * make the compressor extremely slow with some files. Avoid settings
+     * higher than 1000 unless you are prepared to interrupt the compression
+     * in case it is taking far too long.
+     *
+     * @throws      UnsupportedOptionsException
+     *                          <code>depthLimit</code> is invalid
+     */
+    public void setDepthLimit(int depthLimit)
+            throws UnsupportedOptionsException {
+        if (depthLimit < 0)
+            throw new UnsupportedOptionsException(
+                    "Depth limit cannot be negative: " + depthLimit);
+
+        this.depthLimit = depthLimit;
+    }
+
+    /**
+     * Gets the match finder search depth limit.
+     */
+    public int getDepthLimit() {
+        return depthLimit;
+    }
+
+    public int getEncoderMemoryUsage() {
+        return (mode == MODE_UNCOMPRESSED)
+               ? UncompressedLZMA2OutputStream.getMemoryUsage()
+               : LZMA2OutputStream.getMemoryUsage(this);
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        if (mode == MODE_UNCOMPRESSED)
+            return new UncompressedLZMA2OutputStream(out, arrayCache);
+
+        return new LZMA2OutputStream(out, this, arrayCache);
+    }
+
+    /**
+     * Gets how much memory the LZMA2 decoder will need to decompress the data
+     * that was encoded with these options and stored in a .xz file.
+     * <p>
+     * The returned value may bigger than the value returned by a direct call
+     * to {@link LZMA2InputStream#getMemoryUsage(int)} if the dictionary size
+     * is not 2^n or 2^n&nbsp;+&nbsp;2^(n-1) bytes. This is because the .xz
+     * headers store the dictionary size in such a format and other values
+     * are rounded up to the next such value. Such rounding is harmess except
+     * it might waste some memory if an unsual dictionary size is used.
+     * <p>
+     * If you use raw LZMA2 streams and unusual dictioanary size, call
+     * {@link LZMA2InputStream#getMemoryUsage} directly to get raw decoder
+     * memory requirements.
+     */
+    public int getDecoderMemoryUsage() {
+        // Round the dictionary size up to the next 2^n or 2^n + 2^(n-1).
+        int d = dictSize - 1;
+        d |= d >>> 2;
+        d |= d >>> 3;
+        d |= d >>> 4;
+        d |= d >>> 8;
+        d |= d >>> 16;
+        return LZMA2InputStream.getMemoryUsage(d + 1);
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache)
+            throws IOException {
+        return new LZMA2InputStream(in, dictSize, presetDict, arrayCache);
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new LZMA2Encoder(this);
+    }
+
+    public Object clone() {
+        try {
+            return super.clone();
+        } catch (CloneNotSupportedException e) {
+            assert false;
+            throw new RuntimeException();
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/LZMA2OutputStream.java

@@ -0,0 +1,276 @@
+/*
+ * LZMA2OutputStream
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.IOException;
+import org.tukaani.xz.lz.LZEncoder;
+import org.tukaani.xz.rangecoder.RangeEncoderToBuffer;
+import org.tukaani.xz.lzma.LZMAEncoder;
+
+class LZMA2OutputStream extends FinishableOutputStream {
+    static final int COMPRESSED_SIZE_MAX = 64 << 10;
+
+    private final ArrayCache arrayCache;
+
+    private FinishableOutputStream out;
+
+    private LZEncoder lz;
+    private RangeEncoderToBuffer rc;
+    private LZMAEncoder lzma;
+
+    private final int props; // Cannot change props on the fly for now.
+    private boolean dictResetNeeded = true;
+    private boolean stateResetNeeded = true;
+    private boolean propsNeeded = true;
+
+    private int pendingSize = 0;
+    private boolean finished = false;
+    private IOException exception = null;
+
+    private final byte[] chunkHeader = new byte[6];
+
+    private final byte[] tempBuf = new byte[1];
+
+    private static int getExtraSizeBefore(int dictSize) {
+        return COMPRESSED_SIZE_MAX > dictSize
+               ? COMPRESSED_SIZE_MAX - dictSize : 0;
+    }
+
+    static int getMemoryUsage(LZMA2Options options) {
+        // 64 KiB buffer for the range encoder + a little extra + LZMAEncoder
+        int dictSize = options.getDictSize();
+        int extraSizeBefore = getExtraSizeBefore(dictSize);
+        return 70 + LZMAEncoder.getMemoryUsage(options.getMode(),
+                                               dictSize, extraSizeBefore,
+                                               options.getMatchFinder());
+    }
+
+    LZMA2OutputStream(FinishableOutputStream out, LZMA2Options options,
+                      ArrayCache arrayCache) {
+        if (out == null)
+            throw new NullPointerException();
+
+        this.arrayCache = arrayCache;
+        this.out = out;
+        rc = new RangeEncoderToBuffer(COMPRESSED_SIZE_MAX, arrayCache);
+
+        int dictSize = options.getDictSize();
+        int extraSizeBefore = getExtraSizeBefore(dictSize);
+        lzma = LZMAEncoder.getInstance(rc,
+                options.getLc(), options.getLp(), options.getPb(),
+                options.getMode(),
+                dictSize, extraSizeBefore, options.getNiceLen(),
+                options.getMatchFinder(), options.getDepthLimit(),
+                this.arrayCache);
+
+        lz = lzma.getLZEncoder();
+
+        byte[] presetDict = options.getPresetDict();
+        if (presetDict != null && presetDict.length > 0) {
+            lz.setPresetDict(dictSize, presetDict);
+            dictResetNeeded = false;
+        }
+
+        props = (options.getPb() * 5 + options.getLp()) * 9 + options.getLc();
+    }
+
+    public void write(int b) throws IOException {
+        tempBuf[0] = (byte)b;
+        write(tempBuf, 0, 1);
+    }
+
+    public void write(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        try {
+            while (len > 0) {
+                int used = lz.fillWindow(buf, off, len);
+                off += used;
+                len -= used;
+                pendingSize += used;
+
+                if (lzma.encodeForLZMA2())
+                    writeChunk();
+            }
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    private void writeChunk() throws IOException {
+        int compressedSize = rc.finish();
+        int uncompressedSize = lzma.getUncompressedSize();
+
+        assert compressedSize > 0 : compressedSize;
+        assert uncompressedSize > 0 : uncompressedSize;
+
+        // +2 because the header of a compressed chunk is 2 bytes
+        // bigger than the header of an uncompressed chunk.
+        if (compressedSize + 2 < uncompressedSize) {
+            writeLZMA(uncompressedSize, compressedSize);
+        } else {
+            lzma.reset();
+            uncompressedSize = lzma.getUncompressedSize();
+            assert uncompressedSize > 0 : uncompressedSize;
+            writeUncompressed(uncompressedSize);
+        }
+
+        pendingSize -= uncompressedSize;
+        lzma.resetUncompressedSize();
+        rc.reset();
+    }
+
+    private void writeLZMA(int uncompressedSize, int compressedSize)
+            throws IOException {
+        int control;
+
+        if (propsNeeded) {
+            if (dictResetNeeded)
+                control = 0x80 + (3 << 5);
+            else
+                control = 0x80 + (2 << 5);
+        } else {
+            if (stateResetNeeded)
+                control = 0x80 + (1 << 5);
+            else
+                control = 0x80;
+        }
+
+        control |= (uncompressedSize - 1) >>> 16;
+        chunkHeader[0] = (byte)control;
+        chunkHeader[1] = (byte)((uncompressedSize - 1) >>> 8);
+        chunkHeader[2] = (byte)(uncompressedSize - 1);
+        chunkHeader[3] = (byte)((compressedSize - 1) >>> 8);
+        chunkHeader[4] = (byte)(compressedSize - 1);
+
+        if (propsNeeded) {
+            chunkHeader[5] = (byte)props;
+            out.write(chunkHeader, 0, 6);
+        } else {
+            out.write(chunkHeader, 0, 5);
+        }
+
+        rc.write(out);
+
+        propsNeeded = false;
+        stateResetNeeded = false;
+        dictResetNeeded = false;
+    }
+
+    private void writeUncompressed(int uncompressedSize) throws IOException {
+        while (uncompressedSize > 0) {
+            int chunkSize = Math.min(uncompressedSize, COMPRESSED_SIZE_MAX);
+            chunkHeader[0] = (byte)(dictResetNeeded ? 0x01 : 0x02);
+            chunkHeader[1] = (byte)((chunkSize - 1) >>> 8);
+            chunkHeader[2] = (byte)(chunkSize - 1);
+            out.write(chunkHeader, 0, 3);
+            lz.copyUncompressed(out, uncompressedSize, chunkSize);
+            uncompressedSize -= chunkSize;
+            dictResetNeeded = false;
+        }
+
+        stateResetNeeded = true;
+    }
+
+    private void writeEndMarker() throws IOException {
+        assert !finished;
+
+        if (exception != null)
+            throw exception;
+
+        lz.setFinishing();
+
+        try {
+            while (pendingSize > 0) {
+                lzma.encodeForLZMA2();
+                writeChunk();
+            }
+
+            out.write(0x00);
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+
+        finished = true;
+
+        lzma.putArraysToCache(arrayCache);
+        lzma = null;
+        lz = null;
+        rc.putArraysToCache(arrayCache);
+        rc = null;
+    }
+
+    public void flush() throws IOException {
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        try {
+            lz.setFlushing();
+
+            while (pendingSize > 0) {
+                lzma.encodeForLZMA2();
+                writeChunk();
+            }
+
+            out.flush();
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    public void finish() throws IOException {
+        if (!finished) {
+            writeEndMarker();
+
+            try {
+                out.finish();
+            } catch (IOException e) {
+                exception = e;
+                throw e;
+            }
+        }
+    }
+
+    public void close() throws IOException {
+        if (out != null) {
+            if (!finished) {
+                try {
+                    writeEndMarker();
+                } catch (IOException e) {}
+            }
+
+            try {
+                out.close();
+            } catch (IOException e) {
+                if (exception == null)
+                    exception = e;
+            }
+
+            out = null;
+        }
+
+        if (exception != null)
+            throw exception;
+    }
+}

app/src/main/java/org/tukaani/xz/LZMAInputStream.java

@@ -0,0 +1,793 @@
+/*
+ * LZMAInputStream
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.EOFException;
+import org.tukaani.xz.lz.LZDecoder;
+import org.tukaani.xz.rangecoder.RangeDecoderFromStream;
+import org.tukaani.xz.lzma.LZMADecoder;
+
+/**
+ * Decompresses legacy .lzma files and raw LZMA streams (no .lzma header).
+ * <p>
+ * <b>IMPORTANT:</b> In contrast to other classes in this package, this class
+ * reads data from its input stream one byte at a time. If the input stream
+ * is for example {@link java.io.FileInputStream}, wrapping it into
+ * {@link java.io.BufferedInputStream} tends to improve performance a lot.
+ * This is not automatically done by this class because there may be use
+ * cases where it is desired that this class won't read any bytes past
+ * the end of the LZMA stream.
+ * <p>
+ * Even when using <code>BufferedInputStream</code>, the performance tends
+ * to be worse (maybe 10-20&nbsp;% slower) than with {@link LZMA2InputStream}
+ * or {@link XZInputStream} (when the .xz file contains LZMA2-compressed data).
+ *
+ * @since 1.4
+ */
+public class LZMAInputStream extends InputStream {
+    /**
+     * Largest dictionary size supported by this implementation.
+     * <p>
+     * LZMA allows dictionaries up to one byte less than 4 GiB. This
+     * implementation supports only 16 bytes less than 2 GiB. This
+     * limitation is due to Java using signed 32-bit integers for array
+     * indexing. The limitation shouldn't matter much in practice since so
+     * huge dictionaries are not normally used.
+     */
+    public static final int DICT_SIZE_MAX = Integer.MAX_VALUE & ~15;
+
+    private InputStream in;
+    private ArrayCache arrayCache;
+    private LZDecoder lz;
+    private RangeDecoderFromStream rc;
+    private LZMADecoder lzma;
+
+    private boolean endReached = false;
+    private boolean relaxedEndCondition = false;
+
+    private final byte[] tempBuf = new byte[1];
+
+    /**
+     * Number of uncompressed bytes left to be decompressed, or -1 if
+     * the end marker is used.
+     */
+    private long remainingSize;
+
+    private IOException exception = null;
+
+    /**
+     * Gets approximate decompressor memory requirements as kibibytes for
+     * the given dictionary size and LZMA properties byte (lc, lp, and pb).
+     *
+     * @param       dictSize    LZMA dictionary size as bytes, should be
+     *                          in the range [<code>0</code>,
+     *                          <code>DICT_SIZE_MAX</code>]
+     *
+     * @param       propsByte   LZMA properties byte that encodes the values
+     *                          of lc, lp, and pb
+     *
+     * @return      approximate memory requirements as kibibytes (KiB)
+     *
+     * @throws      UnsupportedOptionsException
+     *                          if <code>dictSize</code> is outside
+     *                          the range [<code>0</code>,
+     *                          <code>DICT_SIZE_MAX</code>]
+     *
+     * @throws      CorruptedInputException
+     *                          if <code>propsByte</code> is invalid
+     */
+    public static int getMemoryUsage(int dictSize, byte propsByte)
+            throws UnsupportedOptionsException, CorruptedInputException {
+        if (dictSize < 0 || dictSize > DICT_SIZE_MAX)
+            throw new UnsupportedOptionsException(
+                    "LZMA dictionary is too big for this implementation");
+
+        int props = propsByte & 0xFF;
+        if (props > (4 * 5 + 4) * 9 + 8)
+            throw new CorruptedInputException("Invalid LZMA properties byte");
+
+        props %= 9 * 5;
+        int lp = props / 9;
+        int lc = props - lp * 9;
+
+        return getMemoryUsage(dictSize, lc, lp);
+    }
+
+    /**
+     * Gets approximate decompressor memory requirements as kibibytes for
+     * the given dictionary size, lc, and lp. Note that pb isn't needed.
+     *
+     * @param       dictSize    LZMA dictionary size as bytes, must be
+     *                          in the range [<code>0</code>,
+     *                          <code>DICT_SIZE_MAX</code>]
+     *
+     * @param       lc          number of literal context bits, must be
+     *                          in the range [0, 8]
+     *
+     * @param       lp          number of literal position bits, must be
+     *                          in the range [0, 4]
+     *
+     * @return      approximate memory requirements as kibibytes (KiB)
+     */
+    public static int getMemoryUsage(int dictSize, int lc, int lp) {
+        if (lc < 0 || lc > 8 || lp < 0 || lp > 4)
+            throw new IllegalArgumentException("Invalid lc or lp");
+
+        // Probability variables have the type "short". There are
+        // 0x300 (768) probability variables in each literal subcoder.
+        // The number of literal subcoders is 2^(lc + lp).
+        //
+        // Roughly 10 KiB for the base state + LZ decoder's dictionary buffer
+        // + sizeof(short) * number probability variables per literal subcoder
+        //   * number of literal subcoders
+        return 10 + getDictSize(dictSize) / 1024
+               + ((2 * 0x300) << (lc + lp)) / 1024;
+    }
+
+    private static int getDictSize(int dictSize) {
+        if (dictSize < 0 || dictSize > DICT_SIZE_MAX)
+            throw new IllegalArgumentException(
+                    "LZMA dictionary is too big for this implementation");
+
+        // For performance reasons, use a 4 KiB dictionary if something
+        // smaller was requested. It's a rare situation and the performance
+        // difference isn't huge, and it starts to matter mostly when the
+        // dictionary is just a few bytes. But we need to handle the special
+        // case of dictSize == 0 anyway, which is an allowed value but in
+        // practice means one-byte dictionary.
+        //
+        // Note that using a dictionary bigger than specified in the headers
+        // can hide errors if there is a reference to data beyond the original
+        // dictionary size but is still within 4 KiB.
+        if (dictSize < 4096)
+            dictSize = 4096;
+
+        // Round dictionary size upward to a multiple of 16. This way LZMA
+        // can use LZDecoder.getPos() for calculating LZMA's posMask.
+        return (dictSize + 15) & ~15;
+    }
+
+    /**
+     * Creates a new .lzma file format decompressor without
+     * a memory usage limit.
+     *
+     * @param       in          input stream from which .lzma data is read;
+     *                          it might be a good idea to wrap it in
+     *                          <code>BufferedInputStream</code>, see the
+     *                          note at the top of this page
+     *
+     * @throws      CorruptedInputException
+     *                          file is corrupt or perhaps not in
+     *                          the .lzma format at all
+     *
+     * @throws      UnsupportedOptionsException
+     *                          dictionary size or uncompressed size is too
+     *                          big for this implementation
+     *
+     * @throws      EOFException
+     *                          file is truncated or perhaps not in
+     *                          the .lzma format at all
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public LZMAInputStream(InputStream in) throws IOException {
+        this(in, -1);
+    }
+
+    /**
+     * Creates a new .lzma file format decompressor without
+     * a memory usage limit.
+     * <p>
+     * This is identical to <code>LZMAInputStream(InputStream)</code>
+     * except that this also takes the <code>arrayCache</code> argument.
+     *
+     * @param       in          input stream from which .lzma data is read;
+     *                          it might be a good idea to wrap it in
+     *                          <code>BufferedInputStream</code>, see the
+     *                          note at the top of this page
+     *
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      CorruptedInputException
+     *                          file is corrupt or perhaps not in
+     *                          the .lzma format at all
+     *
+     * @throws      UnsupportedOptionsException
+     *                          dictionary size or uncompressed size is too
+     *                          big for this implementation
+     *
+     * @throws      EOFException
+     *                          file is truncated or perhaps not in
+     *                          the .lzma format at all
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public LZMAInputStream(InputStream in, ArrayCache arrayCache)
+            throws IOException {
+        this(in, -1, arrayCache);
+    }
+
+    /**
+     * Creates a new .lzma file format decompressor with an optional
+     * memory usage limit.
+     *
+     * @param       in          input stream from which .lzma data is read;
+     *                          it might be a good idea to wrap it in
+     *                          <code>BufferedInputStream</code>, see the
+     *                          note at the top of this page
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @throws      CorruptedInputException
+     *                          file is corrupt or perhaps not in
+     *                          the .lzma format at all
+     *
+     * @throws      UnsupportedOptionsException
+     *                          dictionary size or uncompressed size is too
+     *                          big for this implementation
+     *
+     * @throws      MemoryLimitException
+     *                          memory usage limit was exceeded
+     *
+     * @throws      EOFException
+     *                          file is truncated or perhaps not in
+     *                          the .lzma format at all
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public LZMAInputStream(InputStream in, int memoryLimit)
+            throws IOException {
+        this(in, memoryLimit, ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new .lzma file format decompressor with an optional
+     * memory usage limit.
+     * <p>
+     * This is identical to <code>LZMAInputStream(InputStream, int)</code>
+     * except that this also takes the <code>arrayCache</code> argument.
+     *
+     * @param       in          input stream from which .lzma data is read;
+     *                          it might be a good idea to wrap it in
+     *                          <code>BufferedInputStream</code>, see the
+     *                          note at the top of this page
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      CorruptedInputException
+     *                          file is corrupt or perhaps not in
+     *                          the .lzma format at all
+     *
+     * @throws      UnsupportedOptionsException
+     *                          dictionary size or uncompressed size is too
+     *                          big for this implementation
+     *
+     * @throws      MemoryLimitException
+     *                          memory usage limit was exceeded
+     *
+     * @throws      EOFException
+     *                          file is truncated or perhaps not in
+     *                          the .lzma format at all
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public LZMAInputStream(InputStream in, int memoryLimit,
+                           ArrayCache arrayCache) throws IOException {
+        DataInputStream inData = new DataInputStream(in);
+
+        // Properties byte (lc, lp, and pb)
+        byte propsByte = inData.readByte();
+
+        // Dictionary size is an unsigned 32-bit little endian integer.
+        int dictSize = 0;
+        for (int i = 0; i < 4; ++i)
+            dictSize |= inData.readUnsignedByte() << (8 * i);
+
+        // Uncompressed size is an unsigned 64-bit little endian integer.
+        // The maximum 64-bit value is a special case (becomes -1 here)
+        // which indicates that the end marker is used instead of knowing
+        // the uncompressed size beforehand.
+        long uncompSize = 0;
+        for (int i = 0; i < 8; ++i)
+            uncompSize |= (long)inData.readUnsignedByte() << (8 * i);
+
+        // Check the memory usage limit.
+        int memoryNeeded = getMemoryUsage(dictSize, propsByte);
+        if (memoryLimit != -1 && memoryNeeded > memoryLimit)
+            throw new MemoryLimitException(memoryNeeded, memoryLimit);
+
+        initialize(in, uncompSize, propsByte, dictSize, null, arrayCache);
+    }
+
+    /**
+     * Creates a new input stream that decompresses raw LZMA data (no .lzma
+     * header) from <code>in</code>.
+     * <p>
+     * The caller needs to know if the "end of payload marker (EOPM)" alias
+     * "end of stream marker (EOS marker)" alias "end marker" present.
+     * If the end marker isn't used, the caller must know the exact
+     * uncompressed size of the stream.
+     * <p>
+     * The caller also needs to provide the LZMA properties byte that encodes
+     * the number of literal context bits (lc), literal position bits (lp),
+     * and position bits (pb).
+     * <p>
+     * The dictionary size used when compressing is also needed. Specifying
+     * a too small dictionary size will prevent decompressing the stream.
+     * Specifying a too big dictionary is waste of memory but decompression
+     * will work.
+     * <p>
+     * There is no need to specify a dictionary bigger than
+     * the uncompressed size of the data even if a bigger dictionary
+     * was used when compressing. If you know the uncompressed size
+     * of the data, this might allow saving some memory.
+     *
+     * @param       in          input stream from which compressed
+     *                          data is read
+     *
+     * @param       uncompSize  uncompressed size of the LZMA stream or -1
+     *                          if the end marker is used in the LZMA stream
+     *
+     * @param       propsByte   LZMA properties byte that has the encoded
+     *                          values for literal context bits (lc), literal
+     *                          position bits (lp), and position bits (pb)
+     *
+     * @param       dictSize    dictionary size as bytes, must be in the range
+     *                          [<code>0</code>, <code>DICT_SIZE_MAX</code>]
+     *
+     * @throws      CorruptedInputException
+     *                          if <code>propsByte</code> is invalid or
+     *                          the first input byte is not 0x00
+     *
+     * @throws      UnsupportedOptionsException
+     *                          dictionary size or uncompressed size is too
+     *                          big for this implementation
+     *
+     *
+     */
+    public LZMAInputStream(InputStream in, long uncompSize, byte propsByte,
+                           int dictSize) throws IOException {
+        initialize(in, uncompSize, propsByte, dictSize, null,
+                   ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new input stream that decompresses raw LZMA data (no .lzma
+     * header) from <code>in</code> optionally with a preset dictionary.
+     *
+     * @param       in          input stream from which LZMA-compressed
+     *                          data is read
+     *
+     * @param       uncompSize  uncompressed size of the LZMA stream or -1
+     *                          if the end marker is used in the LZMA stream
+     *
+     * @param       propsByte   LZMA properties byte that has the encoded
+     *                          values for literal context bits (lc), literal
+     *                          position bits (lp), and position bits (pb)
+     *
+     * @param       dictSize    dictionary size as bytes, must be in the range
+     *                          [<code>0</code>, <code>DICT_SIZE_MAX</code>]
+     *
+     * @param       presetDict  preset dictionary or <code>null</code>
+     *                          to use no preset dictionary
+     *
+     * @throws      CorruptedInputException
+     *                          if <code>propsByte</code> is invalid or
+     *                          the first input byte is not 0x00
+     *
+     * @throws      UnsupportedOptionsException
+     *                          dictionary size or uncompressed size is too
+     *                          big for this implementation
+     *
+     * @throws      EOFException file is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public LZMAInputStream(InputStream in, long uncompSize, byte propsByte,
+                           int dictSize, byte[] presetDict)
+            throws IOException {
+        initialize(in, uncompSize, propsByte, dictSize, presetDict,
+                   ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new input stream that decompresses raw LZMA data (no .lzma
+     * header) from <code>in</code> optionally with a preset dictionary.
+     * <p>
+     * This is identical to <code>LZMAInputStream(InputStream, long, byte, int,
+     * byte[])</code> except that this also takes the <code>arrayCache</code>
+     * argument.
+     *
+     * @param       in          input stream from which LZMA-compressed
+     *                          data is read
+     *
+     * @param       uncompSize  uncompressed size of the LZMA stream or -1
+     *                          if the end marker is used in the LZMA stream
+     *
+     * @param       propsByte   LZMA properties byte that has the encoded
+     *                          values for literal context bits (lc), literal
+     *                          position bits (lp), and position bits (pb)
+     *
+     * @param       dictSize    dictionary size as bytes, must be in the range
+     *                          [<code>0</code>, <code>DICT_SIZE_MAX</code>]
+     *
+     * @param       presetDict  preset dictionary or <code>null</code>
+     *                          to use no preset dictionary
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      CorruptedInputException
+     *                          if <code>propsByte</code> is invalid or
+     *                          the first input byte is not 0x00
+     *
+     * @throws      UnsupportedOptionsException
+     *                          dictionary size or uncompressed size is too
+     *                          big for this implementation
+     *
+     * @throws      EOFException file is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public LZMAInputStream(InputStream in, long uncompSize, byte propsByte,
+                           int dictSize, byte[] presetDict,
+                           ArrayCache arrayCache)
+            throws IOException {
+        initialize(in, uncompSize, propsByte, dictSize, presetDict,
+                   arrayCache);
+    }
+
+    /**
+     * Creates a new input stream that decompresses raw LZMA data (no .lzma
+     * header) from <code>in</code> optionally with a preset dictionary.
+     *
+     * @param       in          input stream from which LZMA-compressed
+     *                          data is read
+     *
+     * @param       uncompSize  uncompressed size of the LZMA stream or -1
+     *                          if the end marker is used in the LZMA stream
+     *
+     * @param       lc          number of literal context bits, must be
+     *                          in the range [0, 8]
+     *
+     * @param       lp          number of literal position bits, must be
+     *                          in the range [0, 4]
+     *
+     * @param       pb          number position bits, must be
+     *                          in the range [0, 4]
+     *
+     * @param       dictSize    dictionary size as bytes, must be in the range
+     *                          [<code>0</code>, <code>DICT_SIZE_MAX</code>]
+     *
+     * @param       presetDict  preset dictionary or <code>null</code>
+     *                          to use no preset dictionary
+     *
+     * @throws      CorruptedInputException
+     *                          if the first input byte is not 0x00
+     *
+     * @throws      EOFException file is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public LZMAInputStream(InputStream in, long uncompSize,
+                           int lc, int lp, int pb,
+                           int dictSize, byte[] presetDict)
+            throws IOException {
+        initialize(in, uncompSize, lc, lp, pb, dictSize, presetDict,
+                   ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new input stream that decompresses raw LZMA data (no .lzma
+     * header) from <code>in</code> optionally with a preset dictionary.
+     * <p>
+     * This is identical to <code>LZMAInputStream(InputStream, long, int, int,
+     * int, int, byte[])</code> except that this also takes the
+     * <code>arrayCache</code> argument.
+     *
+     * @param       in          input stream from which LZMA-compressed
+     *                          data is read
+     *
+     * @param       uncompSize  uncompressed size of the LZMA stream or -1
+     *                          if the end marker is used in the LZMA stream
+     *
+     * @param       lc          number of literal context bits, must be
+     *                          in the range [0, 8]
+     *
+     * @param       lp          number of literal position bits, must be
+     *                          in the range [0, 4]
+     *
+     * @param       pb          number position bits, must be
+     *                          in the range [0, 4]
+     *
+     * @param       dictSize    dictionary size as bytes, must be in the range
+     *                          [<code>0</code>, <code>DICT_SIZE_MAX</code>]
+     *
+     * @param       presetDict  preset dictionary or <code>null</code>
+     *                          to use no preset dictionary
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      CorruptedInputException
+     *                          if the first input byte is not 0x00
+     *
+     * @throws      EOFException file is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public LZMAInputStream(InputStream in, long uncompSize,
+                           int lc, int lp, int pb,
+                           int dictSize, byte[] presetDict,
+                           ArrayCache arrayCache)
+            throws IOException {
+        initialize(in, uncompSize, lc, lp, pb, dictSize, presetDict,
+                   arrayCache);
+    }
+
+    private void initialize(InputStream in, long uncompSize, byte propsByte,
+                            int dictSize, byte[] presetDict,
+                            ArrayCache arrayCache)
+            throws IOException {
+        // Validate the uncompressed size since the other "initialize" throws
+        // IllegalArgumentException if uncompSize < -1.
+        if (uncompSize < -1)
+            throw new UnsupportedOptionsException(
+                    "Uncompressed size is too big");
+
+        // Decode the properties byte. In contrast to LZMA2, there is no
+        // limit of lc + lp <= 4.
+        int props = propsByte & 0xFF;
+        if (props > (4 * 5 + 4) * 9 + 8)
+            throw new CorruptedInputException("Invalid LZMA properties byte");
+
+        int pb = props / (9 * 5);
+        props -= pb * 9 * 5;
+        int lp = props / 9;
+        int lc = props - lp * 9;
+
+        // Validate the dictionary size since the other "initialize" throws
+        // IllegalArgumentException if dictSize is not supported.
+        if (dictSize < 0 || dictSize > DICT_SIZE_MAX)
+            throw new UnsupportedOptionsException(
+                    "LZMA dictionary is too big for this implementation");
+
+        initialize(in, uncompSize, lc, lp, pb, dictSize, presetDict,
+                   arrayCache);
+    }
+
+    private void initialize(InputStream in, long uncompSize,
+                            int lc, int lp, int pb,
+                            int dictSize, byte[] presetDict,
+                            ArrayCache arrayCache)
+            throws IOException {
+        // getDictSize validates dictSize and gives a message in
+        // the exception too, so skip validating dictSize here.
+        if (uncompSize < -1 || lc < 0 || lc > 8 || lp < 0 || lp > 4
+                || pb < 0 || pb > 4)
+            throw new IllegalArgumentException();
+
+        this.in = in;
+        this.arrayCache = arrayCache;
+
+        // If uncompressed size is known, use it to avoid wasting memory for
+        // a uselessly large dictionary buffer.
+        dictSize = getDictSize(dictSize);
+        if (uncompSize >= 0 && dictSize > uncompSize)
+            dictSize = getDictSize((int)uncompSize);
+
+        lz = new LZDecoder(getDictSize(dictSize), presetDict, arrayCache);
+        rc = new RangeDecoderFromStream(in);
+        lzma = new LZMADecoder(lz, rc, lc, lp, pb);
+
+        remainingSize = uncompSize;
+    }
+
+    /**
+     * Enables relaxed end-of-stream condition when uncompressed size is known.
+     * This is useful if uncompressed size is known but it is unknown if
+     * the end of stream (EOS) marker is present. After calling this function,
+     * both are allowed.
+     * <p>
+     * Note that this doesn't actually check if the EOS marker is present.
+     * This introduces a few minor downsides:
+     * <ul>
+     *   <li>Some (not all!) streams that would have more data than
+     *   the specified uncompressed size, for example due to data corruption,
+     *   will be accepted as valid.</li>
+     *   <li>After <code>read</code> has returned <code>-1</code> the
+     *   input position might not be at the end of the stream (too little
+     *   input may have been read).</li>
+     * </ul>
+     * <p>
+     * This should be called after the constructor before reading any data
+     * from the stream. This is a separate function because adding even more
+     * constructors to this class didn't look like a good alternative.
+     *
+     * @since 1.9
+     */
+    public void enableRelaxedEndCondition() {
+        relaxedEndCondition = true;
+    }
+
+    /**
+     * Decompresses the next byte from this input stream.
+     * <p>
+     * Reading lots of data with <code>read()</code> from this input stream
+     * may be inefficient. Wrap it in <code>java.io.BufferedInputStream</code>
+     * if you need to read lots of data one byte at a time.
+     *
+     * @return      the next decompressed byte, or <code>-1</code>
+     *              to indicate the end of the compressed stream
+     *
+     * @throws      CorruptedInputException
+     *
+     * @throws      XZIOException if the stream has been closed
+     *
+     * @throws      EOFException
+     *                          compressed input is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public int read() throws IOException {
+        return read(tempBuf, 0, 1) == -1 ? -1 : (tempBuf[0] & 0xFF);
+    }
+
+    /**
+     * Decompresses into an array of bytes.
+     * <p>
+     * If <code>len</code> is zero, no bytes are read and <code>0</code>
+     * is returned. Otherwise this will block until <code>len</code>
+     * bytes have been decompressed, the end of the LZMA stream is reached,
+     * or an exception is thrown.
+     *
+     * @param       buf         target buffer for uncompressed data
+     * @param       off         start offset in <code>buf</code>
+     * @param       len         maximum number of uncompressed bytes to read
+     *
+     * @return      number of bytes read, or <code>-1</code> to indicate
+     *              the end of the compressed stream
+     *
+     * @throws      CorruptedInputException
+     *
+     * @throws      XZIOException if the stream has been closed
+     *
+     * @throws      EOFException compressed input is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public int read(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (len == 0)
+            return 0;
+
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        if (endReached)
+            return -1;
+
+        try {
+            int size = 0;
+
+            while (len > 0) {
+                // If uncompressed size is known and thus no end marker will
+                // be present, set the limit so that the uncompressed size
+                // won't be exceeded.
+                int copySizeMax = len;
+                if (remainingSize >= 0 && remainingSize < len)
+                    copySizeMax = (int)remainingSize;
+
+                lz.setLimit(copySizeMax);
+
+                // Decode into the dictionary buffer.
+                try {
+                    lzma.decode();
+                } catch (CorruptedInputException e) {
+                    // The end marker is encoded with a LZMA symbol that
+                    // indicates maximum match distance. This is larger
+                    // than any supported dictionary and thus causes
+                    // CorruptedInputException from LZDecoder.repeat.
+                    if (remainingSize != -1 || !lzma.endMarkerDetected())
+                        throw e;
+
+                    endReached = true;
+
+                    // The exception makes lzma.decode() miss the last range
+                    // decoder normalization, so do it here. This might
+                    // cause an IOException if it needs to read a byte
+                    // from the input stream.
+                    rc.normalize();
+                }
+
+                // Copy from the dictionary to buf.
+                int copiedSize = lz.flush(buf, off);
+                off += copiedSize;
+                len -= copiedSize;
+                size += copiedSize;
+
+                if (remainingSize >= 0) {
+                    // Update the number of bytes left to be decompressed.
+                    remainingSize -= copiedSize;
+                    assert remainingSize >= 0;
+
+                    if (remainingSize == 0)
+                        endReached = true;
+                }
+
+                if (endReached) {
+                    // Checking these helps a lot when catching corrupt
+                    // or truncated .lzma files. LZMA Utils doesn't do
+                    // the second check and thus it accepts many invalid
+                    // files that this implementation and XZ Utils don't.
+                    if (lz.hasPending() || (!relaxedEndCondition
+                                            && !rc.isFinished()))
+                        throw new CorruptedInputException();
+
+                    putArraysToCache();
+                    return size == 0 ? -1 : size;
+                }
+            }
+
+            return size;
+
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    private void putArraysToCache() {
+        if (lz != null) {
+            lz.putArraysToCache(arrayCache);
+            lz = null;
+        }
+    }
+
+    /**
+     * Closes the stream and calls <code>in.close()</code>.
+     * If the stream was already closed, this does nothing.
+     *
+     * @throws  IOException if thrown by <code>in.close()</code>
+     */
+    public void close() throws IOException {
+        if (in != null) {
+            putArraysToCache();
+
+            try {
+                in.close();
+            } finally {
+                in = null;
+            }
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/LZMAOutputStream.java

@@ -0,0 +1,331 @@
+/*
+ * LZMAOutputStream
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.OutputStream;
+import java.io.IOException;
+import org.tukaani.xz.lz.LZEncoder;
+import org.tukaani.xz.rangecoder.RangeEncoderToStream;
+import org.tukaani.xz.lzma.LZMAEncoder;
+
+/**
+ * Compresses into the legacy .lzma file format or into a raw LZMA stream.
+ *
+ * @since 1.6
+ */
+public class LZMAOutputStream extends FinishableOutputStream {
+    private OutputStream out;
+
+    private final ArrayCache arrayCache;
+
+    private LZEncoder lz;
+    private final RangeEncoderToStream rc;
+    private LZMAEncoder lzma;
+
+    private final int props;
+    private final boolean useEndMarker;
+    private final long expectedUncompressedSize;
+    private long currentUncompressedSize = 0;
+
+    private boolean finished = false;
+    private IOException exception = null;
+
+    private final byte[] tempBuf = new byte[1];
+
+    private LZMAOutputStream(OutputStream out, LZMA2Options options,
+                             boolean useHeader, boolean useEndMarker,
+                             long expectedUncompressedSize,
+                             ArrayCache arrayCache)
+            throws IOException {
+        if (out == null)
+            throw new NullPointerException();
+
+        // -1 indicates unknown and >= 0 are for known sizes.
+        if (expectedUncompressedSize < -1)
+            throw new IllegalArgumentException(
+                    "Invalid expected input size (less than -1)");
+
+        this.useEndMarker = useEndMarker;
+        this.expectedUncompressedSize = expectedUncompressedSize;
+
+        this.arrayCache = arrayCache;
+
+        this.out = out;
+        rc = new RangeEncoderToStream(out);
+
+        int dictSize = options.getDictSize();
+        lzma = LZMAEncoder.getInstance(rc,
+                options.getLc(), options.getLp(), options.getPb(),
+                options.getMode(),
+                dictSize, 0, options.getNiceLen(),
+                options.getMatchFinder(), options.getDepthLimit(),
+                arrayCache);
+
+        lz = lzma.getLZEncoder();
+
+        byte[] presetDict = options.getPresetDict();
+        if (presetDict != null && presetDict.length > 0) {
+            if (useHeader)
+                throw new UnsupportedOptionsException(
+                        "Preset dictionary cannot be used in .lzma files "
+                        + "(try a raw LZMA stream instead)");
+
+            lz.setPresetDict(dictSize, presetDict);
+        }
+
+        props = (options.getPb() * 5 + options.getLp()) * 9 + options.getLc();
+
+        if (useHeader) {
+            // Props byte stores lc, lp, and pb.
+            out.write(props);
+
+            // Dictionary size is stored as a 32-bit unsigned little endian
+            // integer.
+            for (int i = 0; i < 4; ++i) {
+                out.write(dictSize & 0xFF);
+                dictSize >>>= 8;
+            }
+
+            // Uncompressed size is stored as a 64-bit unsigned little endian
+            // integer. The max value (-1 in two's complement) indicates
+            // unknown size.
+            for (int i = 0; i < 8; ++i)
+                out.write((int)(expectedUncompressedSize >>> (8 * i)) & 0xFF);
+        }
+    }
+
+    /**
+     * Creates a new compressor for the legacy .lzma file format.
+     * <p>
+     * If the uncompressed size of the input data is known, it will be stored
+     * in the .lzma header and no end of stream marker will be used. Otherwise
+     * the header will indicate unknown uncompressed size and the end of stream
+     * marker will be used.
+     * <p>
+     * Note that a preset dictionary cannot be used in .lzma files but
+     * it can be used for raw LZMA streams.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       options     LZMA compression options; the same class
+     *                          is used here as is for LZMA2
+     *
+     * @param       inputSize   uncompressed size of the data to be compressed;
+     *                          use <code>-1</code> when unknown
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     */
+    public LZMAOutputStream(OutputStream out, LZMA2Options options,
+                            long inputSize)
+            throws IOException {
+        this(out, options, inputSize, ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new compressor for the legacy .lzma file format.
+     * <p>
+     * This is identical to
+     * <code>LZMAOutputStream(OutputStream, LZMA2Options, long)</code>
+     * except that this also takes the <code>arrayCache</code> argument.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       options     LZMA compression options; the same class
+     *                          is used here as is for LZMA2
+     *
+     * @param       inputSize   uncompressed size of the data to be compressed;
+     *                          use <code>-1</code> when unknown
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     *
+     * @since 1.7
+     */
+    public LZMAOutputStream(OutputStream out, LZMA2Options options,
+                            long inputSize, ArrayCache arrayCache)
+            throws IOException {
+        this(out, options, true, inputSize == -1, inputSize, arrayCache);
+    }
+
+    /**
+     * Creates a new compressor for raw LZMA (also known as LZMA1) stream.
+     * <p>
+     * Raw LZMA streams can be encoded with or without end of stream marker.
+     * When decompressing the stream, one must know if the end marker was used
+     * and tell it to the decompressor. If the end marker wasn't used, the
+     * decompressor will also need to know the uncompressed size.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       options     LZMA compression options; the same class
+     *                          is used here as is for LZMA2
+     *
+     * @param       useEndMarker
+     *                          if end of stream marker should be written
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     */
+    public LZMAOutputStream(OutputStream out, LZMA2Options options,
+                            boolean useEndMarker) throws IOException {
+        this(out, options, useEndMarker, ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new compressor for raw LZMA (also known as LZMA1) stream.
+     * <p>
+     * This is identical to
+     * <code>LZMAOutputStream(OutputStream, LZMA2Options, boolean)</code>
+     * except that this also takes the <code>arrayCache</code> argument.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       options     LZMA compression options; the same class
+     *                          is used here as is for LZMA2
+     *
+     * @param       useEndMarker
+     *                          if end of stream marker should be written
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     *
+     * @since 1.7
+     */
+    public LZMAOutputStream(OutputStream out, LZMA2Options options,
+                            boolean useEndMarker, ArrayCache arrayCache)
+            throws IOException {
+        this(out, options, false, useEndMarker, -1, arrayCache);
+    }
+
+    /**
+     * Returns the LZMA lc/lp/pb properties encoded into a single byte.
+     * This might be useful when handling file formats other than .lzma
+     * that use the same encoding for the LZMA properties as .lzma does.
+     */
+    public int getProps() {
+        return props;
+    }
+
+    /**
+     * Gets the amount of uncompressed data written to the stream.
+     * This is useful when creating raw LZMA streams without
+     * the end of stream marker.
+     */
+    public long getUncompressedSize() {
+        return currentUncompressedSize;
+    }
+
+    public void write(int b) throws IOException {
+        tempBuf[0] = (byte)b;
+        write(tempBuf, 0, 1);
+    }
+
+    public void write(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        if (expectedUncompressedSize != -1
+                && expectedUncompressedSize - currentUncompressedSize < len)
+            throw new XZIOException("Expected uncompressed input size ("
+                    + expectedUncompressedSize + " bytes) was exceeded");
+
+        currentUncompressedSize += len;
+
+        try {
+            while (len > 0) {
+                int used = lz.fillWindow(buf, off, len);
+                off += used;
+                len -= used;
+                lzma.encodeForLZMA1();
+            }
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    /**
+     * Flushing isn't supported and will throw XZIOException.
+     */
+    public void flush() throws IOException {
+        throw new XZIOException("LZMAOutputStream does not support flushing");
+    }
+
+    /**
+     * Finishes the stream without closing the underlying OutputStream.
+     */
+    public void finish() throws IOException {
+        if (!finished) {
+            if (exception != null)
+                throw exception;
+
+            try {
+                if (expectedUncompressedSize != -1
+                        && expectedUncompressedSize != currentUncompressedSize)
+                    throw new XZIOException("Expected uncompressed size ("
+                            + expectedUncompressedSize + ") doesn't equal "
+                            + "the number of bytes written to the stream ("
+                            + currentUncompressedSize + ")");
+
+                lz.setFinishing();
+                lzma.encodeForLZMA1();
+
+                if (useEndMarker)
+                    lzma.encodeLZMA1EndMarker();
+
+                rc.finish();
+            } catch (IOException e) {
+                exception = e;
+                throw e;
+            }
+
+            finished = true;
+
+            lzma.putArraysToCache(arrayCache);
+            lzma = null;
+            lz = null;
+        }
+    }
+
+    /**
+     * Finishes the stream and closes the underlying OutputStream.
+     */
+    public void close() throws IOException {
+        if (out != null) {
+            try {
+                finish();
+            } catch (IOException e) {}
+
+            try {
+                out.close();
+            } catch (IOException e) {
+                if (exception == null)
+                    exception = e;
+            }
+
+            out = null;
+        }
+
+        if (exception != null)
+            throw exception;
+    }
+}

app/src/main/java/org/tukaani/xz/MemoryLimitException.java

@@ -0,0 +1,60 @@
+/*
+ * MemoryLimitException
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+/**
+ * Thrown when the memory usage limit given to the XZ decompressor
+ * would be exceeded.
+ * <p>
+ * The amount of memory required and the memory usage limit are
+ * included in the error detail message in human readable format.
+ */
+public class MemoryLimitException extends XZIOException {
+    private static final long serialVersionUID = 3L;
+
+    private final int memoryNeeded;
+    private final int memoryLimit;
+
+    /**
+     * Creates a new MemoryLimitException.
+     * <p>
+     * The amount of memory needed and the memory usage limit are
+     * included in the error detail message.
+     *
+     * @param   memoryNeeded    amount of memory needed as kibibytes (KiB)
+     * @param   memoryLimit     specified memory usage limit as kibibytes (KiB)
+     */
+    public MemoryLimitException(int memoryNeeded, int memoryLimit) {
+        super("" + memoryNeeded + " KiB of memory would be needed; limit was "
+              + memoryLimit + " KiB");
+
+        this.memoryNeeded = memoryNeeded;
+        this.memoryLimit = memoryLimit;
+    }
+
+    /**
+     * Gets how much memory is required to decompress the data.
+     *
+     * @return      amount of memory needed as kibibytes (KiB)
+     */
+    public int getMemoryNeeded() {
+        return memoryNeeded;
+    }
+
+    /**
+     * Gets what the memory usage limit was at the time the exception
+     * was created.
+     *
+     * @return      memory usage limit as kibibytes (KiB)
+     */
+    public int getMemoryLimit() {
+        return memoryLimit;
+    }
+}

app/src/main/java/org/tukaani/xz/PowerPCOptions.java

@@ -0,0 +1,37 @@
+/*
+ * PowerPCOptions
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import org.tukaani.xz.simple.PowerPC;
+
+/**
+ * BCJ filter for big endian PowerPC instructions.
+ */
+public class PowerPCOptions extends BCJOptions {
+    private static final int ALIGNMENT = 4;
+
+    public PowerPCOptions() {
+        super(ALIGNMENT);
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return new SimpleOutputStream(out, new PowerPC(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        return new SimpleInputStream(in, new PowerPC(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.POWERPC_FILTER_ID);
+    }
+}

app/src/main/java/org/tukaani/xz/RawCoder.java

@@ -0,0 +1,33 @@
+/*
+ * RawCoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+class RawCoder {
+    static void validate(FilterCoder[] filters)
+            throws UnsupportedOptionsException {
+        for (int i = 0; i < filters.length - 1; ++i)
+            if (!filters[i].nonLastOK())
+                throw new UnsupportedOptionsException(
+                        "Unsupported XZ filter chain");
+
+        if (!filters[filters.length - 1].lastOK())
+            throw new UnsupportedOptionsException(
+                    "Unsupported XZ filter chain");
+
+        int changesSizeCount = 0;
+        for (int i = 0; i < filters.length; ++i)
+            if (filters[i].changesSize())
+                ++changesSizeCount;
+
+        if (changesSizeCount > 3)
+            throw new UnsupportedOptionsException(
+                    "Unsupported XZ filter chain");
+    }
+}

app/src/main/java/org/tukaani/xz/ResettableArrayCache.java

@@ -0,0 +1,120 @@
+/*
+ * ResettableArrayCache
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * An ArrayCache wrapper that remembers what has been allocated
+ * and allows returning all allocations to the underlying cache at once.
+ *
+ * @since 1.7
+ */
+public class ResettableArrayCache extends ArrayCache {
+    private final ArrayCache arrayCache;
+
+    // Lists of arrays that have been allocated from the arrayCache.
+    private final List<byte[]> byteArrays;
+    private final List<int[]> intArrays;
+
+    /**
+     * Creates a new ResettableArrayCache based on the given ArrayCache.
+     */
+    public ResettableArrayCache(ArrayCache arrayCache) {
+        this.arrayCache = arrayCache;
+
+        // Treat the dummy cache as a special case since it's a common case.
+        // With it we don't need to put the arrays back to the cache and
+        // thus we don't need to remember what has been allocated.
+        if (arrayCache == ArrayCache.getDummyCache()) {
+            byteArrays = null;
+            intArrays = null;
+        } else {
+            byteArrays = new ArrayList<byte[]>();
+            intArrays = new ArrayList<int[]>();
+        }
+    }
+
+    public byte[] getByteArray(int size, boolean fillWithZeros) {
+        byte[] array = arrayCache.getByteArray(size, fillWithZeros);
+
+        if (byteArrays != null) {
+            synchronized(byteArrays) {
+                byteArrays.add(array);
+            }
+        }
+
+        return array;
+    }
+
+    public void putArray(byte[] array) {
+        if (byteArrays != null) {
+            // The array is more likely to be near the end of the list so
+            // start the search from the end.
+            synchronized(byteArrays) {
+                int i = byteArrays.lastIndexOf(array);
+                if (i != -1)
+                    byteArrays.remove(i);
+            }
+
+            arrayCache.putArray(array);
+        }
+    }
+
+    public int[] getIntArray(int size, boolean fillWithZeros) {
+        int[] array = arrayCache.getIntArray(size, fillWithZeros);
+
+        if (intArrays != null) {
+            synchronized(intArrays) {
+                intArrays.add(array);
+            }
+        }
+
+        return array;
+    }
+
+    public void putArray(int[] array) {
+        if (intArrays != null) {
+            synchronized(intArrays) {
+                int i = intArrays.lastIndexOf(array);
+                if (i != -1)
+                    intArrays.remove(i);
+            }
+
+            arrayCache.putArray(array);
+        }
+    }
+
+    /**
+     * Puts all allocated arrays back to the underlying ArrayCache
+     * that haven't already been put there with a call to
+     * {@code putArray}.
+     */
+    public void reset() {
+        if (byteArrays != null) {
+            // Put the arrays to the cache in reverse order: the array that
+            // was allocated first is returned last.
+            synchronized(byteArrays) {
+                for (int i = byteArrays.size() - 1; i >= 0; --i)
+                    arrayCache.putArray(byteArrays.get(i));
+
+                byteArrays.clear();
+            }
+
+            synchronized(intArrays) {
+                for (int i = intArrays.size() - 1; i >= 0; --i)
+                    arrayCache.putArray(intArrays.get(i));
+
+                intArrays.clear();
+            }
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/SPARCOptions.java

@@ -0,0 +1,37 @@
+/*
+ * SPARCOptions
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import org.tukaani.xz.simple.SPARC;
+
+/**
+ * BCJ filter for SPARC.
+ */
+public class SPARCOptions extends BCJOptions {
+    private static final int ALIGNMENT = 4;
+
+    public SPARCOptions() {
+        super(ALIGNMENT);
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return new SimpleOutputStream(out, new SPARC(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        return new SimpleInputStream(in, new SPARC(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.SPARC_FILTER_ID);
+    }
+}

app/src/main/java/org/tukaani/xz/SeekableFileInputStream.java

@@ -0,0 +1,102 @@
+/*
+ * SeekableFileInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.File;
+import java.io.RandomAccessFile;
+import java.io.IOException;
+import java.io.FileNotFoundException;
+
+/**
+ * Wraps a {@link java.io.RandomAccessFile RandomAccessFile}
+ * in a SeekableInputStream.
+ */
+public class SeekableFileInputStream extends SeekableInputStream {
+    /**
+     * The RandomAccessFile that has been wrapped
+     * into a SeekableFileInputStream.
+     */
+    protected RandomAccessFile randomAccessFile;
+
+    /**
+     * Creates a new seekable input stream that reads from the specified file.
+     */
+    public SeekableFileInputStream(File file) throws FileNotFoundException {
+        randomAccessFile = new RandomAccessFile(file, "r");
+    }
+
+    /**
+     * Creates a new seekable input stream that reads from a file with
+     * the specified name.
+     */
+    public SeekableFileInputStream(String name) throws FileNotFoundException {
+        randomAccessFile = new RandomAccessFile(name, "r");
+    }
+
+    /**
+     * Creates a new seekable input stream from an existing
+     * <code>RandomAccessFile</code> object.
+     */
+    public SeekableFileInputStream(RandomAccessFile randomAccessFile) {
+        this.randomAccessFile = randomAccessFile;
+    }
+
+    /**
+     * Calls {@link RandomAccessFile#read() randomAccessFile.read()}.
+     */
+    public int read() throws IOException {
+        return randomAccessFile.read();
+    }
+
+    /**
+     * Calls {@link RandomAccessFile#read(byte[]) randomAccessFile.read(buf)}.
+     */
+    public int read(byte[] buf) throws IOException {
+        return randomAccessFile.read(buf);
+    }
+
+    /**
+     * Calls
+     * {@link RandomAccessFile#read(byte[],int,int)
+     *        randomAccessFile.read(buf, off, len)}.
+     */
+    public int read(byte[] buf, int off, int len) throws IOException {
+        return randomAccessFile.read(buf, off, len);
+    }
+
+    /**
+     * Calls {@link RandomAccessFile#close() randomAccessFile.close()}.
+     */
+    public void close() throws IOException {
+        randomAccessFile.close();
+    }
+
+    /**
+     * Calls {@link RandomAccessFile#length() randomAccessFile.length()}.
+     */
+    public long length() throws IOException {
+        return randomAccessFile.length();
+    }
+
+    /**
+     * Calls {@link RandomAccessFile#getFilePointer()
+                    randomAccessFile.getFilePointer()}.
+     */
+    public long position() throws IOException {
+        return randomAccessFile.getFilePointer();
+    }
+
+    /**
+     * Calls {@link RandomAccessFile#seek(long) randomAccessFile.seek(long)}.
+     */
+    public void seek(long pos) throws IOException {
+        randomAccessFile.seek(pos);
+    }
+}

app/src/main/java/org/tukaani/xz/SeekableInputStream.java

@@ -0,0 +1,81 @@
+/*
+ * SeekableInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.IOException;
+
+/**
+ * Input stream with random access support.
+ */
+public abstract class SeekableInputStream extends InputStream {
+    /**
+     * Seeks <code>n</code> bytes forward in this stream.
+     * <p>
+     * This will not seek past the end of the file. If the current position
+     * is already at or past the end of the file, this doesn't seek at all
+     * and returns <code>0</code>. Otherwise, if skipping <code>n</code> bytes
+     * would cause the position to exceed the stream size, this will do
+     * equivalent of <code>seek(length())</code> and the return value will
+     * be adjusted accordingly.
+     * <p>
+     * If <code>n</code> is negative, the position isn't changed and
+     * the return value is <code>0</code>. It doesn't seek backward
+     * because it would conflict with the specification of
+     * {@link java.io.InputStream#skip(long) InputStream.skip}.
+     *
+     * @return      <code>0</code> if <code>n</code> is negative,
+     *              less than <code>n</code> if skipping <code>n</code>
+     *              bytes would seek past the end of the file,
+     *              <code>n</code> otherwise
+     *
+     * @throws      IOException might be thrown by {@link #seek(long)}
+     */
+    public long skip(long n) throws IOException {
+        if (n <= 0)
+            return 0;
+
+        long size = length();
+        long pos = position();
+        if (pos >= size)
+            return 0;
+
+        if (size - pos < n)
+            n = size - pos;
+
+        seek(pos + n);
+        return n;
+    }
+
+    /**
+     * Gets the size of the stream.
+     */
+    public abstract long length() throws IOException;
+
+    /**
+     * Gets the current position in the stream.
+     */
+    public abstract long position() throws IOException;
+
+    /**
+     * Seeks to the specified absolute position in the stream.
+     * <p>
+     * Seeking past the end of the file should be supported by the subclasses
+     * unless there is a good reason to do otherwise. If one has seeked
+     * past the end of the stream, <code>read</code> will return
+     * <code>-1</code> to indicate end of stream.
+     *
+     * @param       pos         new read position in the stream
+     *
+     * @throws      IOException if <code>pos</code> is negative or if
+     *                          a stream-specific I/O error occurs
+     */
+    public abstract void seek(long pos) throws IOException;
+}

app/src/main/java/org/tukaani/xz/SimpleInputStream.java

@@ -0,0 +1,138 @@
+/*
+ * SimpleInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.IOException;
+import org.tukaani.xz.simple.SimpleFilter;
+
+class SimpleInputStream extends InputStream {
+    private static final int FILTER_BUF_SIZE = 4096;
+
+    private InputStream in;
+    private final SimpleFilter simpleFilter;
+
+    private final byte[] filterBuf = new byte[FILTER_BUF_SIZE];
+    private int pos = 0;
+    private int filtered = 0;
+    private int unfiltered = 0;
+
+    private boolean endReached = false;
+    private IOException exception = null;
+
+    private final byte[] tempBuf = new byte[1];
+
+    static int getMemoryUsage() {
+        return 1 + FILTER_BUF_SIZE / 1024;
+    }
+
+    SimpleInputStream(InputStream in, SimpleFilter simpleFilter) {
+        // Check for null because otherwise null isn't detect
+        // in this constructor.
+        if (in == null)
+            throw new NullPointerException();
+
+        // The simpleFilter argument comes from this package
+        // so it is known to be non-null already.
+        assert simpleFilter != null;
+
+        this.in = in;
+        this.simpleFilter = simpleFilter;
+    }
+
+    public int read() throws IOException {
+        return read(tempBuf, 0, 1) == -1 ? -1 : (tempBuf[0] & 0xFF);
+    }
+
+    public int read(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (len == 0)
+            return 0;
+
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        try {
+            int size = 0;
+
+            while (true) {
+                // Copy filtered data into the caller-provided buffer.
+                int copySize = Math.min(filtered, len);
+                System.arraycopy(filterBuf, pos, buf, off, copySize);
+                pos += copySize;
+                filtered -= copySize;
+                off += copySize;
+                len -= copySize;
+                size += copySize;
+
+                // If end of filterBuf was reached, move the pending data to
+                // the beginning of the buffer so that more data can be
+                // copied into filterBuf on the next loop iteration.
+                if (pos + filtered + unfiltered == FILTER_BUF_SIZE) {
+                    System.arraycopy(filterBuf, pos, filterBuf, 0,
+                                     filtered + unfiltered);
+                    pos = 0;
+                }
+
+                if (len == 0 || endReached)
+                    return size > 0 ? size : -1;
+
+                assert filtered == 0;
+
+                // Get more data into the temporary buffer.
+                int inSize = FILTER_BUF_SIZE - (pos + filtered + unfiltered);
+                inSize = in.read(filterBuf, pos + filtered + unfiltered,
+                                 inSize);
+
+                if (inSize == -1) {
+                    // Mark the remaining unfiltered bytes to be ready
+                    // to be copied out.
+                    endReached = true;
+                    filtered = unfiltered;
+                    unfiltered = 0;
+                } else {
+                    // Filter the data in filterBuf.
+                    unfiltered += inSize;
+                    filtered = simpleFilter.code(filterBuf, pos, unfiltered);
+                    assert filtered <= unfiltered;
+                    unfiltered -= filtered;
+                }
+            }
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    public int available() throws IOException {
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        return filtered;
+    }
+
+    public void close() throws IOException {
+        if (in != null) {
+            try {
+                in.close();
+            } finally {
+                in = null;
+            }
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/SimpleOutputStream.java

@@ -0,0 +1,151 @@
+/*
+ * SimpleOutputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.IOException;
+import org.tukaani.xz.simple.SimpleFilter;
+
+class SimpleOutputStream extends FinishableOutputStream {
+    private static final int FILTER_BUF_SIZE = 4096;
+
+    private FinishableOutputStream out;
+    private final SimpleFilter simpleFilter;
+
+    private final byte[] filterBuf = new byte[FILTER_BUF_SIZE];
+    private int pos = 0;
+    private int unfiltered = 0;
+
+    private IOException exception = null;
+    private boolean finished = false;
+
+    private final byte[] tempBuf = new byte[1];
+
+    static int getMemoryUsage() {
+        return 1 + FILTER_BUF_SIZE / 1024;
+    }
+
+    SimpleOutputStream(FinishableOutputStream out,
+                       SimpleFilter simpleFilter) {
+        if (out == null)
+            throw new NullPointerException();
+
+        this.out = out;
+        this.simpleFilter = simpleFilter;
+    }
+
+    public void write(int b) throws IOException {
+        tempBuf[0] = (byte)b;
+        write(tempBuf, 0, 1);
+    }
+
+    public void write(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        while (len > 0) {
+            // Copy more unfiltered data into filterBuf.
+            int copySize = Math.min(len, FILTER_BUF_SIZE - (pos + unfiltered));
+            System.arraycopy(buf, off, filterBuf, pos + unfiltered, copySize);
+            off += copySize;
+            len -= copySize;
+            unfiltered += copySize;
+
+            // Filter the data in filterBuf.
+            int filtered = simpleFilter.code(filterBuf, pos, unfiltered);
+            assert filtered <= unfiltered;
+            unfiltered -= filtered;
+
+            // Write out the filtered data.
+            try {
+                out.write(filterBuf, pos, filtered);
+            } catch (IOException e) {
+                exception = e;
+                throw e;
+            }
+
+            pos += filtered;
+
+            // If end of filterBuf was reached, move the pending unfiltered
+            // data to the beginning of the buffer so that more data can
+            // be copied into filterBuf on the next loop iteration.
+            if (pos + unfiltered == FILTER_BUF_SIZE) {
+                System.arraycopy(filterBuf, pos, filterBuf, 0, unfiltered);
+                pos = 0;
+            }
+        }
+    }
+
+    private void writePending() throws IOException {
+        assert !finished;
+
+        if (exception != null)
+            throw exception;
+
+        try {
+            out.write(filterBuf, pos, unfiltered);
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+
+        finished = true;
+    }
+
+    public void flush() throws IOException {
+        throw new UnsupportedOptionsException("Flushing is not supported");
+    }
+
+    public void finish() throws IOException {
+        if (!finished) {
+            // If it fails, don't call out.finish().
+            writePending();
+
+            try {
+                out.finish();
+            } catch (IOException e) {
+                exception = e;
+                throw e;
+            }
+        }
+    }
+
+    public void close() throws IOException {
+        if (out != null) {
+            if (!finished) {
+                // out.close() must be called even if writePending() fails.
+                // writePending() saves the possible exception so we can
+                // ignore exceptions here.
+                try {
+                    writePending();
+                } catch (IOException e) {}
+            }
+
+            try {
+                out.close();
+            } catch (IOException e) {
+                // If there is an earlier exception, the exception
+                // from out.close() is lost.
+                if (exception == null)
+                    exception = e;
+            }
+
+            out = null;
+        }
+
+        if (exception != null)
+            throw exception;
+    }
+}

app/src/main/java/org/tukaani/xz/SingleXZInputStream.java

@@ -0,0 +1,535 @@
+/*
+ * SingleXZInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.EOFException;
+import org.tukaani.xz.common.DecoderUtil;
+import org.tukaani.xz.common.StreamFlags;
+import org.tukaani.xz.index.IndexHash;
+import org.tukaani.xz.check.Check;
+
+/**
+ * Decompresses exactly one XZ Stream in streamed mode (no seeking).
+ * The decompression stops after the first XZ Stream has been decompressed,
+ * and the read position in the input stream is left at the first byte
+ * after the end of the XZ Stream. This can be useful when XZ data has
+ * been stored inside some other file format or protocol.
+ * <p>
+ * Unless you know what you are doing, don't use this class to decompress
+ * standalone .xz files. For that purpose, use <code>XZInputStream</code>.
+ *
+ * <h2>When uncompressed size is known beforehand</h2>
+ * <p>
+ * If you are decompressing complete XZ streams and your application knows
+ * exactly how much uncompressed data there should be, it is good to try
+ * reading one more byte by calling <code>read()</code> and checking
+ * that it returns <code>-1</code>. This way the decompressor will parse the
+ * file footers and verify the integrity checks, giving the caller more
+ * confidence that the uncompressed data is valid.
+ *
+ * @see XZInputStream
+ */
+public class SingleXZInputStream extends InputStream {
+    private InputStream in;
+    private final ArrayCache arrayCache;
+    private final int memoryLimit;
+    private final StreamFlags streamHeaderFlags;
+    private final Check check;
+    private final boolean verifyCheck;
+    private BlockInputStream blockDecoder = null;
+    private final IndexHash indexHash = new IndexHash();
+    private boolean endReached = false;
+    private IOException exception = null;
+
+    private final byte[] tempBuf = new byte[1];
+
+    /**
+     * Reads the Stream Header into a buffer.
+     * This is a helper function for the constructors.
+     */
+    private static byte[] readStreamHeader(InputStream in) throws IOException {
+        byte[] streamHeader = new byte[DecoderUtil.STREAM_HEADER_SIZE];
+        new DataInputStream(in).readFully(streamHeader);
+        return streamHeader;
+    }
+
+    /**
+     * Creates a new XZ decompressor that decompresses exactly one
+     * XZ Stream from <code>in</code> without a memory usage limit.
+     * <p>
+     * This constructor reads and parses the XZ Stream Header (12 bytes)
+     * from <code>in</code>. The header of the first Block is not read
+     * until <code>read</code> is called.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public SingleXZInputStream(InputStream in) throws IOException {
+        this(in, -1);
+    }
+
+    /**
+     * Creates a new XZ decompressor that decompresses exactly one
+     * XZ Stream from <code>in</code> without a memory usage limit.
+     * <p>
+     * This is identical to <code>SingleXZInputStream(InputStream)</code>
+     * except that this also takes the <code>arrayCache</code> argument.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public SingleXZInputStream(InputStream in, ArrayCache arrayCache)
+            throws IOException {
+        this(in, -1, arrayCache);
+    }
+
+    /**
+     * Creates a new XZ decompressor that decompresses exactly one
+     * XZ Stream from <code>in</code> with an optional memory usage limit.
+     * <p>
+     * This is identical to <code>SingleXZInputStream(InputStream)</code>
+     * except that this also takes the <code>memoryLimit</code> argument.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public SingleXZInputStream(InputStream in, int memoryLimit)
+            throws IOException {
+        this(in, memoryLimit, true);
+    }
+
+    /**
+     * Creates a new XZ decompressor that decompresses exactly one
+     * XZ Stream from <code>in</code> with an optional memory usage limit.
+     * <p>
+     * This is identical to <code>SingleXZInputStream(InputStream)</code>
+     * except that this also takes the <code>memoryLimit</code> and
+     * <code>arrayCache</code> arguments.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public SingleXZInputStream(InputStream in, int memoryLimit,
+                               ArrayCache arrayCache) throws IOException {
+        this(in, memoryLimit, true, arrayCache);
+    }
+
+    /**
+     * Creates a new XZ decompressor that decompresses exactly one
+     * XZ Stream from <code>in</code> with an optional memory usage limit
+     * and ability to disable verification of integrity checks.
+     * <p>
+     * This is identical to <code>SingleXZInputStream(InputStream,int)</code>
+     * except that this also takes the <code>verifyCheck</code> argument.
+     * <p>
+     * Note that integrity check verification should almost never be disabled.
+     * Possible reasons to disable integrity check verification:
+     * <ul>
+     *   <li>Trying to recover data from a corrupt .xz file.</li>
+     *   <li>Speeding up decompression. This matters mostly with SHA-256
+     *   or with files that have compressed extremely well. It's recommended
+     *   that integrity checking isn't disabled for performance reasons
+     *   unless the file integrity is verified externally in some other
+     *   way.</li>
+     * </ul>
+     * <p>
+     * <code>verifyCheck</code> only affects the integrity check of
+     * the actual compressed data. The CRC32 fields in the headers
+     * are always verified.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @param       verifyCheck if <code>true</code>, the integrity checks
+     *                          will be verified; this should almost never
+     *                          be set to <code>false</code>
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.6
+     */
+    public SingleXZInputStream(InputStream in, int memoryLimit,
+                               boolean verifyCheck) throws IOException {
+        this(in, memoryLimit, verifyCheck, ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new XZ decompressor that decompresses exactly one
+     * XZ Stream from <code>in</code> with an optional memory usage limit
+     * and ability to disable verification of integrity checks.
+     * <p>
+     * This is identical to
+     * <code>SingleXZInputStream(InputStream,int,boolean)</code>
+     * except that this also takes the <code>arrayCache</code> argument.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @param       verifyCheck if <code>true</code>, the integrity checks
+     *                          will be verified; this should almost never
+     *                          be set to <code>false</code>
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public SingleXZInputStream(InputStream in, int memoryLimit,
+                               boolean verifyCheck, ArrayCache arrayCache)
+            throws IOException {
+        this(in, memoryLimit, verifyCheck, readStreamHeader(in), arrayCache);
+    }
+
+    SingleXZInputStream(InputStream in, int memoryLimit, boolean verifyCheck,
+                        byte[] streamHeader, ArrayCache arrayCache)
+            throws IOException {
+        this.arrayCache = arrayCache;
+        this.in = in;
+        this.memoryLimit = memoryLimit;
+        this.verifyCheck = verifyCheck;
+        streamHeaderFlags = DecoderUtil.decodeStreamHeader(streamHeader);
+        check = Check.getInstance(streamHeaderFlags.checkType);
+    }
+
+    /**
+     * Gets the ID of the integrity check used in this XZ Stream.
+     *
+     * @return      the Check ID specified in the XZ Stream Header
+     */
+    public int getCheckType() {
+        return streamHeaderFlags.checkType;
+    }
+
+    /**
+     * Gets the name of the integrity check used in this XZ Stream.
+     *
+     * @return      the name of the check specified in the XZ Stream Header
+     */
+    public String getCheckName() {
+        return check.getName();
+    }
+
+    /**
+     * Decompresses the next byte from this input stream.
+     * <p>
+     * Reading lots of data with <code>read()</code> from this input stream
+     * may be inefficient. Wrap it in {@link java.io.BufferedInputStream}
+     * if you need to read lots of data one byte at a time.
+     *
+     * @return      the next decompressed byte, or <code>-1</code>
+     *              to indicate the end of the compressed stream
+     *
+     * @throws      CorruptedInputException
+     * @throws      UnsupportedOptionsException
+     * @throws      MemoryLimitException
+     *
+     * @throws      XZIOException if the stream has been closed
+     *
+     * @throws      EOFException
+     *                          compressed input is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public int read() throws IOException {
+        return read(tempBuf, 0, 1) == -1 ? -1 : (tempBuf[0] & 0xFF);
+    }
+
+    /**
+     * Decompresses into an array of bytes.
+     * <p>
+     * If <code>len</code> is zero, no bytes are read and <code>0</code>
+     * is returned. Otherwise this will try to decompress <code>len</code>
+     * bytes of uncompressed data. Less than <code>len</code> bytes may
+     * be read only in the following situations:
+     * <ul>
+     *   <li>The end of the compressed data was reached successfully.</li>
+     *   <li>An error is detected after at least one but less <code>len</code>
+     *       bytes have already been successfully decompressed.
+     *       The next call with non-zero <code>len</code> will immediately
+     *       throw the pending exception.</li>
+     *   <li>An exception is thrown.</li>
+     * </ul>
+     *
+     * @param       buf         target buffer for uncompressed data
+     * @param       off         start offset in <code>buf</code>
+     * @param       len         maximum number of uncompressed bytes to read
+     *
+     * @return      number of bytes read, or <code>-1</code> to indicate
+     *              the end of the compressed stream
+     *
+     * @throws      CorruptedInputException
+     * @throws      UnsupportedOptionsException
+     * @throws      MemoryLimitException
+     *
+     * @throws      XZIOException if the stream has been closed
+     *
+     * @throws      EOFException
+     *                          compressed input is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public int read(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (len == 0)
+            return 0;
+
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        if (endReached)
+            return -1;
+
+        int size = 0;
+
+        try {
+            while (len > 0) {
+                if (blockDecoder == null) {
+                    try {
+                        blockDecoder = new BlockInputStream(
+                                in, check, verifyCheck, memoryLimit, -1, -1,
+                                arrayCache);
+                    } catch (IndexIndicatorException e) {
+                        indexHash.validate(in);
+                        validateStreamFooter();
+                        endReached = true;
+                        return size > 0 ? size : -1;
+                    }
+                }
+
+                int ret = blockDecoder.read(buf, off, len);
+
+                if (ret > 0) {
+                    size += ret;
+                    off += ret;
+                    len -= ret;
+                } else if (ret == -1) {
+                    indexHash.add(blockDecoder.getUnpaddedSize(),
+                                  blockDecoder.getUncompressedSize());
+                    blockDecoder = null;
+                }
+            }
+        } catch (IOException e) {
+            exception = e;
+            if (size == 0)
+                throw e;
+        }
+
+        return size;
+    }
+
+    private void validateStreamFooter() throws IOException {
+        byte[] buf = new byte[DecoderUtil.STREAM_HEADER_SIZE];
+        new DataInputStream(in).readFully(buf);
+        StreamFlags streamFooterFlags = DecoderUtil.decodeStreamFooter(buf);
+
+        if (!DecoderUtil.areStreamFlagsEqual(streamHeaderFlags,
+                                             streamFooterFlags)
+                || indexHash.getIndexSize() != streamFooterFlags.backwardSize)
+            throw new CorruptedInputException(
+                    "XZ Stream Footer does not match Stream Header");
+    }
+
+    /**
+     * Returns the number of uncompressed bytes that can be read
+     * without blocking. The value is returned with an assumption
+     * that the compressed input data will be valid. If the compressed
+     * data is corrupt, <code>CorruptedInputException</code> may get
+     * thrown before the number of bytes claimed to be available have
+     * been read from this input stream.
+     *
+     * @return      the number of uncompressed bytes that can be read
+     *              without blocking
+     */
+    public int available() throws IOException {
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        return blockDecoder == null ? 0 : blockDecoder.available();
+    }
+
+    /**
+     * Closes the stream and calls <code>in.close()</code>.
+     * If the stream was already closed, this does nothing.
+     * <p>
+     * This is equivalent to <code>close(true)</code>.
+     *
+     * @throws  IOException if thrown by <code>in.close()</code>
+     */
+    public void close() throws IOException {
+        close(true);
+    }
+
+    /**
+     * Closes the stream and optionally calls <code>in.close()</code>.
+     * If the stream was already closed, this does nothing.
+     * If <code>close(false)</code> has been called, a further
+     * call of <code>close(true)</code> does nothing (it doesn't call
+     * <code>in.close()</code>).
+     * <p>
+     * If you don't want to close the underlying <code>InputStream</code>,
+     * there is usually no need to worry about closing this stream either;
+     * it's fine to do nothing and let the garbage collector handle it.
+     * However, if you are using {@link ArrayCache}, <code>close(false)</code>
+     * can be useful to put the allocated arrays back to the cache without
+     * closing the underlying <code>InputStream</code>.
+     * <p>
+     * Note that if you successfully reach the end of the stream
+     * (<code>read</code> returns <code>-1</code>), the arrays are
+     * automatically put back to the cache by that <code>read</code> call. In
+     * this situation <code>close(false)</code> is redundant (but harmless).
+     *
+     * @throws  IOException if thrown by <code>in.close()</code>
+     *
+     * @since 1.7
+     */
+    public void close(boolean closeInput) throws IOException {
+        if (in != null) {
+            if (blockDecoder != null) {
+                blockDecoder.close();
+                blockDecoder = null;
+            }
+
+            try {
+                if (closeInput)
+                    in.close();
+            } finally {
+                in = null;
+            }
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/UncompressedLZMA2OutputStream.java

@@ -0,0 +1,164 @@
+/*
+ * UncompressedLZMA2OutputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+class UncompressedLZMA2OutputStream extends FinishableOutputStream {
+    private final ArrayCache arrayCache;
+
+    private FinishableOutputStream out;
+    private final DataOutputStream outData;
+
+    private final byte[] uncompBuf;
+    private int uncompPos = 0;
+    private boolean dictResetNeeded = true;
+
+    private boolean finished = false;
+    private IOException exception = null;
+
+    private final byte[] tempBuf = new byte[1];
+
+    static int getMemoryUsage() {
+        // uncompBuf + a little extra
+        return 70;
+    }
+
+    UncompressedLZMA2OutputStream(FinishableOutputStream out,
+                                  ArrayCache arrayCache) {
+        if (out == null)
+            throw new NullPointerException();
+
+        this.out = out;
+        outData = new DataOutputStream(out);
+
+        // We only allocate one array from the cache. We will call
+        // putArray directly in writeEndMarker and thus we don't use
+        // ResettableArrayCache here.
+        this.arrayCache = arrayCache;
+        uncompBuf = arrayCache.getByteArray(
+                LZMA2OutputStream.COMPRESSED_SIZE_MAX, false);
+    }
+
+    public void write(int b) throws IOException {
+        tempBuf[0] = (byte)b;
+        write(tempBuf, 0, 1);
+    }
+
+    public void write(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        try {
+            while (len > 0) {
+                int copySize = Math.min(LZMA2OutputStream.COMPRESSED_SIZE_MAX
+                                        - uncompPos, len);
+                System.arraycopy(buf, off, uncompBuf, uncompPos, copySize);
+                len -= copySize;
+                uncompPos += copySize;
+
+                if (uncompPos == LZMA2OutputStream.COMPRESSED_SIZE_MAX)
+                    writeChunk();
+            }
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    private void writeChunk() throws IOException {
+        outData.writeByte(dictResetNeeded ? 0x01 : 0x02);
+        outData.writeShort(uncompPos - 1);
+        outData.write(uncompBuf, 0, uncompPos);
+        uncompPos = 0;
+        dictResetNeeded = false;
+    }
+
+    private void writeEndMarker() throws IOException {
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        try {
+            if (uncompPos > 0)
+                writeChunk();
+
+            out.write(0x00);
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+
+        finished = true;
+        arrayCache.putArray(uncompBuf);
+    }
+
+    public void flush() throws IOException {
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        try {
+            if (uncompPos > 0)
+                writeChunk();
+
+            out.flush();
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    public void finish() throws IOException {
+        if (!finished) {
+            writeEndMarker();
+
+            try {
+                out.finish();
+            } catch (IOException e) {
+                exception = e;
+                throw e;
+            }
+        }
+    }
+
+    public void close() throws IOException {
+        if (out != null) {
+            if (!finished) {
+                try {
+                    writeEndMarker();
+                } catch (IOException e) {}
+            }
+
+            try {
+                out.close();
+            } catch (IOException e) {
+                if (exception == null)
+                    exception = e;
+            }
+
+            out = null;
+        }
+
+        if (exception != null)
+            throw exception;
+    }
+}

app/src/main/java/org/tukaani/xz/UnsupportedOptionsException.java

@@ -0,0 +1,34 @@
+/*
+ * UnsupportedOptionsException
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+/**
+ * Thrown when compression options not supported by this implementation
+ * are detected. Some other implementation might support those options.
+ */
+public class UnsupportedOptionsException extends XZIOException {
+    private static final long serialVersionUID = 3L;
+
+    /**
+     * Creates a new UnsupportedOptionsException with null
+     * as its error detail message.
+     */
+    public UnsupportedOptionsException() {}
+
+    /**
+     * Creates a new UnsupportedOptionsException with the given
+     * error detail message.
+     *
+     * @param       s           error detail message
+     */
+    public UnsupportedOptionsException(String s) {
+        super(s);
+    }
+}

app/src/main/java/org/tukaani/xz/X86Options.java

@@ -0,0 +1,37 @@
+/*
+ * X86Options
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import org.tukaani.xz.simple.X86;
+
+/**
+ * BCJ filter for x86 (32-bit and 64-bit) instructions.
+ */
+public class X86Options extends BCJOptions {
+    private static final int ALIGNMENT = 1;
+
+    public X86Options() {
+        super(ALIGNMENT);
+    }
+
+    public FinishableOutputStream getOutputStream(FinishableOutputStream out,
+                                                  ArrayCache arrayCache) {
+        return new SimpleOutputStream(out, new X86(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in, ArrayCache arrayCache) {
+        return new SimpleInputStream(in, new X86(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.X86_FILTER_ID);
+    }
+}

app/src/main/java/org/tukaani/xz/XZ.java

@@ -0,0 +1,53 @@
+/*
+ * XZ
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+/**
+ * XZ constants.
+ */
+public class XZ {
+    /**
+     * XZ Header Magic Bytes begin a XZ file.
+     * This can be useful to detect XZ compressed data.
+     */
+    public static final byte[] HEADER_MAGIC = {
+            (byte)0xFD, '7', 'z', 'X', 'Z', '\0' };
+
+    /**
+     * XZ Footer Magic Bytes are the last bytes of a XZ Stream.
+     */
+    public static final byte[] FOOTER_MAGIC = { 'Y', 'Z' };
+
+    /**
+     * Integrity check ID indicating that no integrity check is calculated.
+     * <p>
+     * Omitting the integrity check is strongly discouraged except when
+     * the integrity of the data will be verified by other means anyway,
+     * and calculating the check twice would be useless.
+     */
+    public static final int CHECK_NONE = 0;
+
+    /**
+     * Integrity check ID for CRC32.
+     */
+    public static final int CHECK_CRC32 = 1;
+
+    /**
+     * Integrity check ID for CRC64.
+     */
+    public static final int CHECK_CRC64 = 4;
+
+    /**
+     * Integrity check ID for SHA-256.
+     */
+    public static final int CHECK_SHA256 = 10;
+
+    private XZ() {}
+}

app/src/main/java/org/tukaani/xz/XZFormatException.java

@@ -0,0 +1,24 @@
+/*
+ * XZFormatException
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+/**
+ * Thrown when the input data is not in the XZ format.
+ */
+public class XZFormatException extends XZIOException {
+    private static final long serialVersionUID = 3L;
+
+    /**
+     * Creates a new exception with the default error detail message.
+     */
+    public XZFormatException() {
+        super("Input is not in the XZ format");
+    }
+}

app/src/main/java/org/tukaani/xz/XZIOException.java

@@ -0,0 +1,27 @@
+/*
+ * XZIOException
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+/**
+ * Generic {@link java.io.IOException IOException} specific to this package.
+ * The other IOExceptions in this package extend
+ * from <code>XZIOException</code>.
+ */
+public class XZIOException extends java.io.IOException {
+    private static final long serialVersionUID = 3L;
+
+    public XZIOException() {
+        super();
+    }
+
+    public XZIOException(String s) {
+        super(s);
+    }
+}

app/src/main/java/org/tukaani/xz/XZInputStream.java

@@ -0,0 +1,527 @@
+/*
+ * XZInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.EOFException;
+import org.tukaani.xz.common.DecoderUtil;
+
+/**
+ * Decompresses a .xz file in streamed mode (no seeking).
+ * <p>
+ * Use this to decompress regular standalone .xz files. This reads from
+ * its input stream until the end of the input or until an error occurs.
+ * This supports decompressing concatenated .xz files.
+ *
+ * <h2>Typical use cases</h2>
+ * <p>
+ * Getting an input stream to decompress a .xz file:
+ * <blockquote><pre>
+ * InputStream infile = new FileInputStream("foo.xz");
+ * XZInputStream inxz = new XZInputStream(infile);
+ * </pre></blockquote>
+ * <p>
+ * It's important to keep in mind that decompressor memory usage depends
+ * on the settings used to compress the file. The worst-case memory usage
+ * of XZInputStream is currently 1.5&nbsp;GiB. Still, very few files will
+ * require more than about 65&nbsp;MiB because that's how much decompressing
+ * a file created with the highest preset level will need, and only a few
+ * people use settings other than the predefined presets.
+ * <p>
+ * It is possible to specify a memory usage limit for
+ * <code>XZInputStream</code>. If decompression requires more memory than
+ * the specified limit, MemoryLimitException will be thrown when reading
+ * from the stream. For example, the following sets the memory usage limit
+ * to 100&nbsp;MiB:
+ * <blockquote><pre>
+ * InputStream infile = new FileInputStream("foo.xz");
+ * XZInputStream inxz = new XZInputStream(infile, 100 * 1024);
+ * </pre></blockquote>
+ *
+ * <h2>When uncompressed size is known beforehand</h2>
+ * <p>
+ * If you are decompressing complete files and your application knows
+ * exactly how much uncompressed data there should be, it is good to try
+ * reading one more byte by calling <code>read()</code> and checking
+ * that it returns <code>-1</code>. This way the decompressor will parse the
+ * file footers and verify the integrity checks, giving the caller more
+ * confidence that the uncompressed data is valid. (This advice seems to
+ * apply to
+ * {@link java.util.zip.GZIPInputStream java.util.zip.GZIPInputStream} too.)
+ *
+ * @see SingleXZInputStream
+ */
+public class XZInputStream extends InputStream {
+    private final ArrayCache arrayCache;
+
+    private final int memoryLimit;
+    private InputStream in;
+    private SingleXZInputStream xzIn;
+    private final boolean verifyCheck;
+    private boolean endReached = false;
+    private IOException exception = null;
+
+    private final byte[] tempBuf = new byte[1];
+
+    /**
+     * Creates a new XZ decompressor without a memory usage limit.
+     * <p>
+     * This constructor reads and parses the XZ Stream Header (12 bytes)
+     * from <code>in</code>. The header of the first Block is not read
+     * until <code>read</code> is called.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public XZInputStream(InputStream in) throws IOException {
+        this(in, -1);
+    }
+
+    /**
+     * Creates a new XZ decompressor without a memory usage limit.
+     * <p>
+     * This is identical to <code>XZInputStream(InputStream)</code>
+     * except that this takes also the <code>arrayCache</code> argument.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public XZInputStream(InputStream in, ArrayCache arrayCache)
+            throws IOException {
+        this(in, -1, arrayCache);
+    }
+
+    /**
+     * Creates a new XZ decompressor with an optional memory usage limit.
+     * <p>
+     * This is identical to <code>XZInputStream(InputStream)</code> except
+     * that this takes also the <code>memoryLimit</code> argument.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public XZInputStream(InputStream in, int memoryLimit) throws IOException {
+        this(in, memoryLimit, true);
+    }
+
+    /**
+     * Creates a new XZ decompressor with an optional memory usage limit.
+     * <p>
+     * This is identical to <code>XZInputStream(InputStream)</code> except
+     * that this takes also the <code>memoryLimit</code> and
+     * <code>arrayCache</code> arguments.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public XZInputStream(InputStream in, int memoryLimit,
+                         ArrayCache arrayCache) throws IOException {
+        this(in, memoryLimit, true, arrayCache);
+    }
+
+    /**
+     * Creates a new XZ decompressor with an optional memory usage limit
+     * and ability to disable verification of integrity checks.
+     * <p>
+     * This is identical to <code>XZInputStream(InputStream,int)</code> except
+     * that this takes also the <code>verifyCheck</code> argument.
+     * <p>
+     * Note that integrity check verification should almost never be disabled.
+     * Possible reasons to disable integrity check verification:
+     * <ul>
+     *   <li>Trying to recover data from a corrupt .xz file.</li>
+     *   <li>Speeding up decompression. This matters mostly with SHA-256
+     *   or with files that have compressed extremely well. It's recommended
+     *   that integrity checking isn't disabled for performance reasons
+     *   unless the file integrity is verified externally in some other
+     *   way.</li>
+     * </ul>
+     * <p>
+     * <code>verifyCheck</code> only affects the integrity check of
+     * the actual compressed data. The CRC32 fields in the headers
+     * are always verified.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @param       verifyCheck if <code>true</code>, the integrity checks
+     *                          will be verified; this should almost never
+     *                          be set to <code>false</code>
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.6
+     */
+    public XZInputStream(InputStream in, int memoryLimit, boolean verifyCheck)
+            throws IOException {
+        this(in, memoryLimit, verifyCheck, ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new XZ decompressor with an optional memory usage limit
+     * and ability to disable verification of integrity checks.
+     * <p>
+     * This is identical to <code>XZInputStream(InputStream,int,boolean)</code>
+     * except that this takes also the <code>arrayCache</code> argument.
+     *
+     * @param       in          input stream from which XZ-compressed
+     *                          data is read
+     *
+     * @param       memoryLimit memory usage limit in kibibytes (KiB)
+     *                          or <code>-1</code> to impose no
+     *                          memory usage limit
+     *
+     * @param       verifyCheck if <code>true</code>, the integrity checks
+     *                          will be verified; this should almost never
+     *                          be set to <code>false</code>
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      XZFormatException
+     *                          input is not in the XZ format
+     *
+     * @throws      CorruptedInputException
+     *                          XZ header CRC32 doesn't match
+     *
+     * @throws      UnsupportedOptionsException
+     *                          XZ header is valid but specifies options
+     *                          not supported by this implementation
+     *
+     * @throws      EOFException
+     *                          less than 12 bytes of input was available
+     *                          from <code>in</code>
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     *
+     * @since 1.7
+     */
+    public XZInputStream(InputStream in, int memoryLimit, boolean verifyCheck,
+                         ArrayCache arrayCache) throws IOException {
+        this.arrayCache = arrayCache;
+        this.in = in;
+        this.memoryLimit = memoryLimit;
+        this.verifyCheck = verifyCheck;
+        this.xzIn = new SingleXZInputStream(in, memoryLimit, verifyCheck,
+                                            arrayCache);
+    }
+
+    /**
+     * Decompresses the next byte from this input stream.
+     * <p>
+     * Reading lots of data with <code>read()</code> from this input stream
+     * may be inefficient. Wrap it in {@link java.io.BufferedInputStream}
+     * if you need to read lots of data one byte at a time.
+     *
+     * @return      the next decompressed byte, or <code>-1</code>
+     *              to indicate the end of the compressed stream
+     *
+     * @throws      CorruptedInputException
+     * @throws      UnsupportedOptionsException
+     * @throws      MemoryLimitException
+     *
+     * @throws      XZIOException if the stream has been closed
+     *
+     * @throws      EOFException
+     *                          compressed input is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public int read() throws IOException {
+        return read(tempBuf, 0, 1) == -1 ? -1 : (tempBuf[0] & 0xFF);
+    }
+
+    /**
+     * Decompresses into an array of bytes.
+     * <p>
+     * If <code>len</code> is zero, no bytes are read and <code>0</code>
+     * is returned. Otherwise this will try to decompress <code>len</code>
+     * bytes of uncompressed data. Less than <code>len</code> bytes may
+     * be read only in the following situations:
+     * <ul>
+     *   <li>The end of the compressed data was reached successfully.</li>
+     *   <li>An error is detected after at least one but less <code>len</code>
+     *       bytes have already been successfully decompressed.
+     *       The next call with non-zero <code>len</code> will immediately
+     *       throw the pending exception.</li>
+     *   <li>An exception is thrown.</li>
+     * </ul>
+     *
+     * @param       buf         target buffer for uncompressed data
+     * @param       off         start offset in <code>buf</code>
+     * @param       len         maximum number of uncompressed bytes to read
+     *
+     * @return      number of bytes read, or <code>-1</code> to indicate
+     *              the end of the compressed stream
+     *
+     * @throws      CorruptedInputException
+     * @throws      UnsupportedOptionsException
+     * @throws      MemoryLimitException
+     *
+     * @throws      XZIOException if the stream has been closed
+     *
+     * @throws      EOFException
+     *                          compressed input is truncated or corrupt
+     *
+     * @throws      IOException may be thrown by <code>in</code>
+     */
+    public int read(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (len == 0)
+            return 0;
+
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        if (endReached)
+            return -1;
+
+        int size = 0;
+
+        try {
+            while (len > 0) {
+                if (xzIn == null) {
+                    prepareNextStream();
+                    if (endReached)
+                        return size == 0 ? -1 : size;
+                }
+
+                int ret = xzIn.read(buf, off, len);
+
+                if (ret > 0) {
+                    size += ret;
+                    off += ret;
+                    len -= ret;
+                } else if (ret == -1) {
+                    xzIn = null;
+                }
+            }
+        } catch (IOException e) {
+            exception = e;
+            if (size == 0)
+                throw e;
+        }
+
+        return size;
+    }
+
+    private void prepareNextStream() throws IOException {
+        DataInputStream inData = new DataInputStream(in);
+        byte[] buf = new byte[DecoderUtil.STREAM_HEADER_SIZE];
+
+        // The size of Stream Padding must be a multiple of four bytes,
+        // all bytes zero.
+        do {
+            // First try to read one byte to see if we have reached the end
+            // of the file.
+            int ret = inData.read(buf, 0, 1);
+            if (ret == -1) {
+                endReached = true;
+                return;
+            }
+
+            // Since we got one byte of input, there must be at least
+            // three more available in a valid file.
+            inData.readFully(buf, 1, 3);
+
+        } while (buf[0] == 0 && buf[1] == 0 && buf[2] == 0 && buf[3] == 0);
+
+        // Not all bytes are zero. In a valid Stream it indicates the
+        // beginning of the next Stream. Read the rest of the Stream Header
+        // and initialize the XZ decoder.
+        inData.readFully(buf, 4, DecoderUtil.STREAM_HEADER_SIZE - 4);
+
+        try {
+            xzIn = new SingleXZInputStream(in, memoryLimit, verifyCheck, buf,
+                                           arrayCache);
+        } catch (XZFormatException e) {
+            // Since this isn't the first .xz Stream, it is more
+            // logical to tell that the data is corrupt.
+            throw new CorruptedInputException(
+                    "Garbage after a valid XZ Stream");
+        }
+    }
+
+    /**
+     * Returns the number of uncompressed bytes that can be read
+     * without blocking. The value is returned with an assumption
+     * that the compressed input data will be valid. If the compressed
+     * data is corrupt, <code>CorruptedInputException</code> may get
+     * thrown before the number of bytes claimed to be available have
+     * been read from this input stream.
+     *
+     * @return      the number of uncompressed bytes that can be read
+     *              without blocking
+     */
+    public int available() throws IOException {
+        if (in == null)
+            throw new XZIOException("Stream closed");
+
+        if (exception != null)
+            throw exception;
+
+        return xzIn == null ? 0 : xzIn.available();
+    }
+
+    /**
+     * Closes the stream and calls <code>in.close()</code>.
+     * If the stream was already closed, this does nothing.
+     * <p>
+     * This is equivalent to <code>close(true)</code>.
+     *
+     * @throws  IOException if thrown by <code>in.close()</code>
+     */
+    public void close() throws IOException {
+        close(true);
+    }
+
+    /**
+     * Closes the stream and optionally calls <code>in.close()</code>.
+     * If the stream was already closed, this does nothing.
+     * If <code>close(false)</code> has been called, a further
+     * call of <code>close(true)</code> does nothing (it doesn't call
+     * <code>in.close()</code>).
+     * <p>
+     * If you don't want to close the underlying <code>InputStream</code>,
+     * there is usually no need to worry about closing this stream either;
+     * it's fine to do nothing and let the garbage collector handle it.
+     * However, if you are using {@link ArrayCache}, <code>close(false)</code>
+     * can be useful to put the allocated arrays back to the cache without
+     * closing the underlying <code>InputStream</code>.
+     * <p>
+     * Note that if you successfully reach the end of the stream
+     * (<code>read</code> returns <code>-1</code>), the arrays are
+     * automatically put back to the cache by that <code>read</code> call. In
+     * this situation <code>close(false)</code> is redundant (but harmless).
+     *
+     * @throws  IOException if thrown by <code>in.close()</code>
+     *
+     * @since 1.7
+     */
+    public void close(boolean closeInput) throws IOException {
+        if (in != null) {
+            if (xzIn != null) {
+                xzIn.close(false);
+                xzIn = null;
+            }
+
+            try {
+                if (closeInput)
+                    in.close();
+            } finally {
+                in = null;
+            }
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/XZOutputStream.java

@@ -0,0 +1,606 @@
+/*
+ * XZOutputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.OutputStream;
+import java.io.IOException;
+import org.tukaani.xz.common.EncoderUtil;
+import org.tukaani.xz.common.StreamFlags;
+import org.tukaani.xz.check.Check;
+import org.tukaani.xz.index.IndexEncoder;
+
+/**
+ * Compresses into the .xz file format.
+ *
+ * <h2>Examples</h2>
+ * <p>
+ * Getting an output stream to compress with LZMA2 using the default
+ * settings and the default integrity check type (CRC64):
+ * <blockquote><pre>
+ * FileOutputStream outfile = new FileOutputStream("foo.xz");
+ * XZOutputStream outxz = new XZOutputStream(outfile, new LZMA2Options());
+ * </pre></blockquote>
+ * <p>
+ * Using the preset level <code>8</code> for LZMA2 (the default
+ * is <code>6</code>) and SHA-256 instead of CRC64 for integrity checking:
+ * <blockquote><pre>
+ * XZOutputStream outxz = new XZOutputStream(outfile, new LZMA2Options(8),
+ *                                           XZ.CHECK_SHA256);
+ * </pre></blockquote>
+ * <p>
+ * Using the x86 BCJ filter together with LZMA2 to compress x86 executables
+ * and printing the memory usage information before creating the
+ * XZOutputStream:
+ * <blockquote><pre>
+ * X86Options x86 = new X86Options();
+ * LZMA2Options lzma2 = new LZMA2Options();
+ * FilterOptions[] options = { x86, lzma2 };
+ * System.out.println("Encoder memory usage: "
+ *                    + FilterOptions.getEncoderMemoryUsage(options)
+ *                    + " KiB");
+ * System.out.println("Decoder memory usage: "
+ *                    + FilterOptions.getDecoderMemoryUsage(options)
+ *                    + " KiB");
+ * XZOutputStream outxz = new XZOutputStream(outfile, options);
+ * </pre></blockquote>
+ */
+public class XZOutputStream extends FinishableOutputStream {
+    private final ArrayCache arrayCache;
+
+    private OutputStream out;
+    private final StreamFlags streamFlags = new StreamFlags();
+    private final Check check;
+    private final IndexEncoder index = new IndexEncoder();
+
+    private BlockOutputStream blockEncoder = null;
+    private FilterEncoder[] filters;
+
+    /**
+     * True if the current filter chain supports flushing.
+     * If it doesn't support flushing, <code>flush()</code>
+     * will use <code>endBlock()</code> as a fallback.
+     */
+    private boolean filtersSupportFlushing;
+
+    private IOException exception = null;
+    private boolean finished = false;
+
+    private final byte[] tempBuf = new byte[1];
+
+    /**
+     * Creates a new XZ compressor using one filter and CRC64 as
+     * the integrity check. This constructor is equivalent to passing
+     * a single-member FilterOptions array to
+     * <code>XZOutputStream(OutputStream, FilterOptions[])</code>.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       filterOptions
+     *                          filter options to use
+     *
+     * @throws      UnsupportedOptionsException
+     *                          invalid filter chain
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     */
+    public XZOutputStream(OutputStream out, FilterOptions filterOptions)
+            throws IOException {
+        this(out, filterOptions, XZ.CHECK_CRC64);
+    }
+
+    /**
+     * Creates a new XZ compressor using one filter and CRC64 as
+     * the integrity check. This constructor is equivalent to passing
+     * a single-member FilterOptions array to
+     * <code>XZOutputStream(OutputStream, FilterOptions[], ArrayCache)</code>.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       filterOptions
+     *                          filter options to use
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      UnsupportedOptionsException
+     *                          invalid filter chain
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     *
+     * @since 1.7
+     */
+    public XZOutputStream(OutputStream out, FilterOptions filterOptions,
+                          ArrayCache arrayCache)
+            throws IOException {
+        this(out, filterOptions, XZ.CHECK_CRC64, arrayCache);
+    }
+
+    /**
+     * Creates a new XZ compressor using one filter and the specified
+     * integrity check type. This constructor is equivalent to
+     * passing a single-member FilterOptions array to
+     * <code>XZOutputStream(OutputStream, FilterOptions[], int)</code>.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       filterOptions
+     *                          filter options to use
+     *
+     * @param       checkType   type of the integrity check,
+     *                          for example XZ.CHECK_CRC32
+     *
+     * @throws      UnsupportedOptionsException
+     *                          invalid filter chain
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     */
+    public XZOutputStream(OutputStream out, FilterOptions filterOptions,
+                          int checkType) throws IOException {
+        this(out, new FilterOptions[] { filterOptions }, checkType);
+    }
+
+    /**
+     * Creates a new XZ compressor using one filter and the specified
+     * integrity check type. This constructor is equivalent to
+     * passing a single-member FilterOptions array to
+     * <code>XZOutputStream(OutputStream, FilterOptions[], int,
+     * ArrayCache)</code>.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       filterOptions
+     *                          filter options to use
+     *
+     * @param       checkType   type of the integrity check,
+     *                          for example XZ.CHECK_CRC32
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      UnsupportedOptionsException
+     *                          invalid filter chain
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     *
+     * @since 1.7
+     */
+    public XZOutputStream(OutputStream out, FilterOptions filterOptions,
+                          int checkType, ArrayCache arrayCache)
+            throws IOException {
+        this(out, new FilterOptions[] { filterOptions }, checkType,
+             arrayCache);
+    }
+
+    /**
+     * Creates a new XZ compressor using 1-4 filters and CRC64 as
+     * the integrity check. This constructor is equivalent
+     * <code>XZOutputStream(out, filterOptions, XZ.CHECK_CRC64)</code>.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       filterOptions
+     *                          array of filter options to use
+     *
+     * @throws      UnsupportedOptionsException
+     *                          invalid filter chain
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     */
+    public XZOutputStream(OutputStream out, FilterOptions[] filterOptions)
+            throws IOException {
+        this(out, filterOptions, XZ.CHECK_CRC64);
+    }
+
+    /**
+     * Creates a new XZ compressor using 1-4 filters and CRC64 as
+     * the integrity check. This constructor is equivalent
+     * <code>XZOutputStream(out, filterOptions, XZ.CHECK_CRC64,
+     * arrayCache)</code>.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       filterOptions
+     *                          array of filter options to use
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      UnsupportedOptionsException
+     *                          invalid filter chain
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     *
+     * @since 1.7
+     */
+    public XZOutputStream(OutputStream out, FilterOptions[] filterOptions,
+                          ArrayCache arrayCache)
+            throws IOException {
+        this(out, filterOptions, XZ.CHECK_CRC64, arrayCache);
+    }
+
+    /**
+     * Creates a new XZ compressor using 1-4 filters and the specified
+     * integrity check type.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       filterOptions
+     *                          array of filter options to use
+     *
+     * @param       checkType   type of the integrity check,
+     *                          for example XZ.CHECK_CRC32
+     *
+     * @throws      UnsupportedOptionsException
+     *                          invalid filter chain
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     */
+    public XZOutputStream(OutputStream out, FilterOptions[] filterOptions,
+                          int checkType) throws IOException {
+        this(out, filterOptions, checkType, ArrayCache.getDefaultCache());
+    }
+
+    /**
+     * Creates a new XZ compressor using 1-4 filters and the specified
+     * integrity check type.
+     *
+     * @param       out         output stream to which the compressed data
+     *                          will be written
+     *
+     * @param       filterOptions
+     *                          array of filter options to use
+     *
+     * @param       checkType   type of the integrity check,
+     *                          for example XZ.CHECK_CRC32
+     *
+     * @param       arrayCache  cache to be used for allocating large arrays
+     *
+     * @throws      UnsupportedOptionsException
+     *                          invalid filter chain
+     *
+     * @throws      IOException may be thrown from <code>out</code>
+     *
+     * @since 1.7
+     */
+    public XZOutputStream(OutputStream out, FilterOptions[] filterOptions,
+                          int checkType, ArrayCache arrayCache)
+            throws IOException {
+        this.arrayCache = arrayCache;
+        this.out = out;
+        updateFilters(filterOptions);
+
+        streamFlags.checkType = checkType;
+        check = Check.getInstance(checkType);
+
+        encodeStreamHeader();
+    }
+
+    /**
+     * Updates the filter chain with a single filter.
+     * This is equivalent to passing a single-member FilterOptions array
+     * to <code>updateFilters(FilterOptions[])</code>.
+     *
+     * @param       filterOptions
+     *                          new filter to use
+     *
+     * @throws      UnsupportedOptionsException
+     *                          unsupported filter chain, or trying to change
+     *                          the filter chain in the middle of a Block
+     */
+    public void updateFilters(FilterOptions filterOptions)
+            throws XZIOException {
+        FilterOptions[] opts = new FilterOptions[1];
+        opts[0] = filterOptions;
+        updateFilters(opts);
+    }
+
+    /**
+     * Updates the filter chain with 1-4 filters.
+     * <p>
+     * Currently this cannot be used to update e.g. LZMA2 options in the
+     * middle of a XZ Block. Use <code>endBlock()</code> to finish the
+     * current XZ Block before calling this function. The new filter chain
+     * will then be used for the next XZ Block.
+     *
+     * @param       filterOptions
+     *                          new filter chain to use
+     *
+     * @throws      UnsupportedOptionsException
+     *                          unsupported filter chain, or trying to change
+     *                          the filter chain in the middle of a Block
+     */
+    public void updateFilters(FilterOptions[] filterOptions)
+            throws XZIOException {
+        if (blockEncoder != null)
+            throw new UnsupportedOptionsException("Changing filter options "
+                    + "in the middle of a XZ Block not implemented");
+
+        if (filterOptions.length < 1 || filterOptions.length > 4)
+            throw new UnsupportedOptionsException(
+                        "XZ filter chain must be 1-4 filters");
+
+        filtersSupportFlushing = true;
+        FilterEncoder[] newFilters = new FilterEncoder[filterOptions.length];
+        for (int i = 0; i < filterOptions.length; ++i) {
+            newFilters[i] = filterOptions[i].getFilterEncoder();
+            filtersSupportFlushing &= newFilters[i].supportsFlushing();
+        }
+
+        RawCoder.validate(newFilters);
+        filters = newFilters;
+    }
+
+    /**
+     * Writes one byte to be compressed.
+     *
+     * @throws      XZIOException
+     *                          XZ Stream has grown too big
+     *
+     * @throws      XZIOException
+     *                          <code>finish()</code> or <code>close()</code>
+     *                          was already called
+     *
+     * @throws      IOException may be thrown by the underlying output stream
+     */
+    public void write(int b) throws IOException {
+        tempBuf[0] = (byte)b;
+        write(tempBuf, 0, 1);
+    }
+
+    /**
+     * Writes an array of bytes to be compressed.
+     * The compressors tend to do internal buffering and thus the written
+     * data won't be readable from the compressed output immediately.
+     * Use <code>flush()</code> to force everything written so far to
+     * be written to the underlaying output stream, but be aware that
+     * flushing reduces compression ratio.
+     *
+     * @param       buf         buffer of bytes to be written
+     * @param       off         start offset in <code>buf</code>
+     * @param       len         number of bytes to write
+     *
+     * @throws      XZIOException
+     *                          XZ Stream has grown too big: total file size
+     *                          about 8&nbsp;EiB or the Index field exceeds
+     *                          16&nbsp;GiB; you shouldn't reach these sizes
+     *                          in practice
+     *
+     * @throws      XZIOException
+     *                          <code>finish()</code> or <code>close()</code>
+     *                          was already called and len &gt; 0
+     *
+     * @throws      IOException may be thrown by the underlying output stream
+     */
+    public void write(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IndexOutOfBoundsException();
+
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        try {
+            if (blockEncoder == null)
+                blockEncoder = new BlockOutputStream(out, filters, check,
+                                                     arrayCache);
+
+            blockEncoder.write(buf, off, len);
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    /**
+     * Finishes the current XZ Block (but not the whole XZ Stream).
+     * This doesn't flush the stream so it's possible that not all data will
+     * be decompressible from the output stream when this function returns.
+     * Call also <code>flush()</code> if flushing is wanted in addition to
+     * finishing the current XZ Block.
+     * <p>
+     * If there is no unfinished Block open, this function will do nothing.
+     * (No empty XZ Block will be created.)
+     * <p>
+     * This function can be useful, for example, to create
+     * random-accessible .xz files.
+     * <p>
+     * Starting a new XZ Block means that the encoder state is reset.
+     * Doing this very often will increase the size of the compressed
+     * file a lot (more than plain <code>flush()</code> would do).
+     *
+     * @throws      XZIOException
+     *                          XZ Stream has grown too big
+     *
+     * @throws      XZIOException
+     *                          stream finished or closed
+     *
+     * @throws      IOException may be thrown by the underlying output stream
+     */
+    public void endBlock() throws IOException {
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        // NOTE: Once there is threading with multiple Blocks, it's possible
+        // that this function will be more like a barrier that returns
+        // before the last Block has been finished.
+        if (blockEncoder != null) {
+            try {
+                blockEncoder.finish();
+                index.add(blockEncoder.getUnpaddedSize(),
+                          blockEncoder.getUncompressedSize());
+                blockEncoder = null;
+            } catch (IOException e) {
+                exception = e;
+                throw e;
+            }
+        }
+    }
+
+    /**
+     * Flushes the encoder and calls <code>out.flush()</code>.
+     * All buffered pending data will then be decompressible from
+     * the output stream.
+     * <p>
+     * Calling this function very often may increase the compressed
+     * file size a lot. The filter chain options may affect the size
+     * increase too. For example, with LZMA2 the HC4 match finder has
+     * smaller penalty with flushing than BT4.
+     * <p>
+     * Some filters don't support flushing. If the filter chain has
+     * such a filter, <code>flush()</code> will call <code>endBlock()</code>
+     * before flushing.
+     *
+     * @throws      XZIOException
+     *                          XZ Stream has grown too big
+     *
+     * @throws      XZIOException
+     *                          stream finished or closed
+     *
+     * @throws      IOException may be thrown by the underlying output stream
+     */
+    public void flush() throws IOException {
+        if (exception != null)
+            throw exception;
+
+        if (finished)
+            throw new XZIOException("Stream finished or closed");
+
+        try {
+            if (blockEncoder != null) {
+                if (filtersSupportFlushing) {
+                    // This will eventually call out.flush() so
+                    // no need to do it here again.
+                    blockEncoder.flush();
+                } else {
+                    endBlock();
+                    out.flush();
+                }
+            } else {
+                out.flush();
+            }
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+
+    /**
+     * Finishes compression without closing the underlying stream.
+     * No more data can be written to this stream after finishing
+     * (calling <code>write</code> with an empty buffer is OK).
+     * <p>
+     * Repeated calls to <code>finish()</code> do nothing unless
+     * an exception was thrown by this stream earlier. In that case
+     * the same exception is thrown again.
+     * <p>
+     * After finishing, the stream may be closed normally with
+     * <code>close()</code>. If the stream will be closed anyway, there
+     * usually is no need to call <code>finish()</code> separately.
+     *
+     * @throws      XZIOException
+     *                          XZ Stream has grown too big
+     *
+     * @throws      IOException may be thrown by the underlying output stream
+     */
+    public void finish() throws IOException {
+        if (!finished) {
+            // This checks for pending exceptions so we don't need to
+            // worry about it here.
+            endBlock();
+
+            try {
+                index.encode(out);
+                encodeStreamFooter();
+            } catch (IOException e) {
+                exception = e;
+                throw e;
+            }
+
+            // Set it to true only if everything goes fine. Setting it earlier
+            // would cause repeated calls to finish() do nothing instead of
+            // throwing an exception to indicate an earlier error.
+            finished = true;
+        }
+    }
+
+    /**
+     * Finishes compression and closes the underlying stream.
+     * The underlying stream <code>out</code> is closed even if finishing
+     * fails. If both finishing and closing fail, the exception thrown
+     * by <code>finish()</code> is thrown and the exception from the failed
+     * <code>out.close()</code> is lost.
+     *
+     * @throws      XZIOException
+     *                          XZ Stream has grown too big
+     *
+     * @throws      IOException may be thrown by the underlying output stream
+     */
+    public void close() throws IOException {
+        if (out != null) {
+            // If finish() throws an exception, it stores the exception to
+            // the variable "exception". So we can ignore the possible
+            // exception here.
+            try {
+                finish();
+            } catch (IOException e) {}
+
+            try {
+                out.close();
+            } catch (IOException e) {
+                // Remember the exception but only if there is no previous
+                // pending exception.
+                if (exception == null)
+                    exception = e;
+            }
+
+            out = null;
+        }
+
+        if (exception != null)
+            throw exception;
+    }
+
+    private void encodeStreamFlags(byte[] buf, int off) {
+        buf[off] = 0x00;
+        buf[off + 1] = (byte)streamFlags.checkType;
+    }
+
+    private void encodeStreamHeader() throws IOException {
+        out.write(XZ.HEADER_MAGIC);
+
+        byte[] buf = new byte[2];
+        encodeStreamFlags(buf, 0);
+        out.write(buf);
+
+        EncoderUtil.writeCRC32(out, buf);
+    }
+
+    private void encodeStreamFooter() throws IOException {
+        byte[] buf = new byte[6];
+        long backwardSize = index.getIndexSize() / 4 - 1;
+        for (int i = 0; i < 4; ++i)
+            buf[i] = (byte)(backwardSize >>> (i * 8));
+
+        encodeStreamFlags(buf, 4);
+
+        EncoderUtil.writeCRC32(out, buf);
+        out.write(buf);
+        out.write(XZ.FOOTER_MAGIC);
+    }
+}

app/src/main/java/org/tukaani/xz/check/CRC32.java

@@ -0,0 +1,33 @@
+/*
+ * CRC32
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.check;
+
+public class CRC32 extends Check {
+    private final java.util.zip.CRC32 state = new java.util.zip.CRC32();
+
+    public CRC32() {
+        size = 4;
+        name = "CRC32";
+    }
+
+    public void update(byte[] buf, int off, int len) {
+        state.update(buf, off, len);
+    }
+
+    public byte[] finish() {
+        long value = state.getValue();
+        byte[] buf = { (byte)(value),
+                       (byte)(value >>> 8),
+                       (byte)(value >>> 16),
+                       (byte)(value >>> 24) };
+        state.reset();
+        return buf;
+    }
+}

app/src/main/java/org/tukaani/xz/check/CRC64.java

@@ -0,0 +1,71 @@
+/*
+ * CRC64
+ *
+ * Authors: Brett Okken <brett.okken.os@gmail.com>
+ *          Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.check;
+
+public class CRC64 extends Check {
+    private static final long[][] TABLE = new long[4][256];
+
+    static {
+        final long poly64 = 0xC96C5795D7870F42L;
+
+        for (int s = 0; s < 4; ++s) {
+            for (int b = 0; b < 256; ++b) {
+                long r = s == 0 ? b : TABLE[s - 1][b];
+                for (int i = 0; i < 8; ++i) {
+                    if ((r & 1) == 1) {
+                        r = (r >>> 1) ^ poly64;
+                    } else {
+                        r >>>= 1;
+                    }
+                }
+                TABLE[s][b] = r;
+            }
+        }
+    }
+
+    private long crc = -1;
+
+    public CRC64() {
+        size = 8;
+        name = "CRC64";
+    }
+
+    @Override
+    public void update(byte[] buf, int off, int len) {
+        final int end = off + len;
+        int i = off;
+
+        for (int end4 = end - 3; i < end4; i += 4) {
+            final int tmp = (int)crc;
+            crc = TABLE[3][(tmp & 0xFF) ^ (buf[i] & 0xFF)] ^
+                  TABLE[2][((tmp >>> 8) & 0xFF) ^ (buf[i + 1] & 0xFF)] ^
+                  (crc >>> 32) ^
+                  TABLE[1][((tmp >>> 16) & 0xFF) ^ (buf[i + 2] & 0xFF)] ^
+                  TABLE[0][((tmp >>> 24) & 0xFF) ^ (buf[i + 3] & 0xFF)];
+        }
+
+        while (i < end)
+            crc = TABLE[0][(buf[i++] & 0xFF) ^ ((int)crc & 0xFF)] ^
+                  (crc >>> 8);
+    }
+
+    @Override
+    public byte[] finish() {
+        long value = ~crc;
+        crc = -1;
+
+        byte[] buf = new byte[8];
+        for (int i = 0; i < buf.length; ++i)
+            buf[i] = (byte)(value >> (i * 8));
+
+        return buf;
+    }
+}

app/src/main/java/org/tukaani/xz/check/Check.java

@@ -0,0 +1,57 @@
+/*
+ * Check
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.check;
+
+import org.tukaani.xz.XZ;
+import org.tukaani.xz.UnsupportedOptionsException;
+
+public abstract class Check {
+    int size;
+    String name;
+
+    public abstract void update(byte[] buf, int off, int len);
+    public abstract byte[] finish();
+
+    public void update(byte[] buf) {
+        update(buf, 0, buf.length);
+    }
+
+    public int getSize() {
+        return size;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public static Check getInstance(int checkType)
+            throws UnsupportedOptionsException {
+        switch (checkType) {
+            case XZ.CHECK_NONE:
+                return new None();
+
+            case XZ.CHECK_CRC32:
+                return new CRC32();
+
+            case XZ.CHECK_CRC64:
+                return new CRC64();
+
+            case XZ.CHECK_SHA256:
+                try {
+                    return new SHA256();
+                } catch (java.security.NoSuchAlgorithmException e) {}
+
+                break;
+        }
+
+        throw new UnsupportedOptionsException(
+                "Unsupported Check ID " + checkType);
+    }
+}

app/src/main/java/org/tukaani/xz/check/None.java

@@ -0,0 +1,24 @@
+/*
+ * None
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.check;
+
+public class None extends Check {
+    public None() {
+        size = 0;
+        name = "None";
+    }
+
+    public void update(byte[] buf, int off, int len) {}
+
+    public byte[] finish() {
+        byte[] empty = new byte[0];
+        return empty;
+    }
+}

app/src/main/java/org/tukaani/xz/check/SHA256.java

@@ -0,0 +1,30 @@
+/*
+ * SHA256
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.check;
+
+public class SHA256 extends Check {
+    private final java.security.MessageDigest sha256;
+
+    public SHA256() throws java.security.NoSuchAlgorithmException {
+        size = 32;
+        name = "SHA-256";
+        sha256 = java.security.MessageDigest.getInstance("SHA-256");
+    }
+
+    public void update(byte[] buf, int off, int len) {
+        sha256.update(buf, off, len);
+    }
+
+    public byte[] finish() {
+        byte[] buf = sha256.digest();
+        sha256.reset();
+        return buf;
+    }
+}

app/src/main/java/org/tukaani/xz/common/DecoderUtil.java

@@ -0,0 +1,121 @@
+/*
+ * DecoderUtil
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.common;
+
+import java.io.InputStream;
+import java.io.IOException;
+import java.io.EOFException;
+import java.util.zip.CRC32;
+import org.tukaani.xz.XZ;
+import org.tukaani.xz.XZFormatException;
+import org.tukaani.xz.CorruptedInputException;
+import org.tukaani.xz.UnsupportedOptionsException;
+
+public class DecoderUtil extends Util {
+    public static boolean isCRC32Valid(byte[] buf, int off, int len,
+                                       int ref_off) {
+        CRC32 crc32 = new CRC32();
+        crc32.update(buf, off, len);
+        long value = crc32.getValue();
+
+        for (int i = 0; i < 4; ++i)
+            if ((byte)(value >>> (i * 8)) != buf[ref_off + i])
+                return false;
+
+        return true;
+    }
+
+    public static StreamFlags decodeStreamHeader(byte[] buf)
+            throws IOException {
+        for (int i = 0; i < XZ.HEADER_MAGIC.length; ++i)
+            if (buf[i] != XZ.HEADER_MAGIC[i])
+                throw new XZFormatException();
+
+        if (!isCRC32Valid(buf, XZ.HEADER_MAGIC.length, 2,
+                          XZ.HEADER_MAGIC.length + 2))
+            throw new CorruptedInputException("XZ Stream Header is corrupt");
+
+        try {
+            return decodeStreamFlags(buf, XZ.HEADER_MAGIC.length);
+        } catch (UnsupportedOptionsException e) {
+            throw new UnsupportedOptionsException(
+                    "Unsupported options in XZ Stream Header");
+        }
+    }
+
+    public static StreamFlags decodeStreamFooter(byte[] buf)
+            throws IOException {
+        if (buf[10] != XZ.FOOTER_MAGIC[0] || buf[11] != XZ.FOOTER_MAGIC[1]) {
+            // NOTE: The exception could be XZFormatException too.
+            // It depends on the situation which one is better.
+            throw new CorruptedInputException("XZ Stream Footer is corrupt");
+        }
+
+        if (!isCRC32Valid(buf, 4, 6, 0))
+            throw new CorruptedInputException("XZ Stream Footer is corrupt");
+
+        StreamFlags streamFlags;
+        try {
+            streamFlags = decodeStreamFlags(buf, 8);
+        } catch (UnsupportedOptionsException e) {
+            throw new UnsupportedOptionsException(
+                    "Unsupported options in XZ Stream Footer");
+        }
+
+        streamFlags.backwardSize = 0;
+        for (int i = 0; i < 4; ++i)
+            streamFlags.backwardSize |= (buf[i + 4] & 0xFF) << (i * 8);
+
+        streamFlags.backwardSize = (streamFlags.backwardSize + 1) * 4;
+
+        return streamFlags;
+    }
+
+    private static StreamFlags decodeStreamFlags(byte[] buf, int off)
+            throws UnsupportedOptionsException {
+        if (buf[off] != 0x00 || (buf[off + 1] & 0xFF) >= 0x10)
+            throw new UnsupportedOptionsException();
+
+        StreamFlags streamFlags = new StreamFlags();
+        streamFlags.checkType = buf[off + 1];
+
+        return streamFlags;
+    }
+
+    public static boolean areStreamFlagsEqual(StreamFlags a, StreamFlags b) {
+        // backwardSize is intentionally not compared.
+        return a.checkType == b.checkType;
+    }
+
+    public static long decodeVLI(InputStream in) throws IOException {
+        int b = in.read();
+        if (b == -1)
+            throw new EOFException();
+
+        long num = b & 0x7F;
+        int i = 0;
+
+        while ((b & 0x80) != 0x00) {
+            if (++i >= VLI_SIZE_MAX)
+                throw new CorruptedInputException();
+
+            b = in.read();
+            if (b == -1)
+                throw new EOFException();
+
+            if (b == 0x00)
+                throw new CorruptedInputException();
+
+            num |= (long)(b & 0x7F) << (i * 7);
+        }
+
+        return num;
+    }
+}

app/src/main/java/org/tukaani/xz/common/EncoderUtil.java

@@ -0,0 +1,36 @@
+/*
+ * EncoderUtil
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.common;
+
+import java.io.OutputStream;
+import java.io.IOException;
+import java.util.zip.CRC32;
+
+public class EncoderUtil extends Util {
+    public static void writeCRC32(OutputStream out, byte[] buf)
+            throws IOException {
+        CRC32 crc32 = new CRC32();
+        crc32.update(buf);
+        long value = crc32.getValue();
+
+        for (int i = 0; i < 4; ++i)
+            out.write((byte)(value >>> (i * 8)));
+    }
+
+    public static void encodeVLI(OutputStream out, long num)
+            throws IOException {
+        while (num >= 0x80) {
+            out.write((byte)(num | 0x80));
+            num >>>= 7;
+        }
+
+        out.write((byte)num);
+    }
+}

app/src/main/java/org/tukaani/xz/common/StreamFlags.java

@@ -0,0 +1,15 @@
+/*
+ * StreamFlags
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.common;
+
+public class StreamFlags {
+    public int checkType = -1;
+    public long backwardSize = -1;
+}

app/src/main/java/org/tukaani/xz/common/Util.java

@@ -0,0 +1,28 @@
+/*
+ * Util
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.common;
+
+public class Util {
+    public static final int STREAM_HEADER_SIZE = 12;
+    public static final long BACKWARD_SIZE_MAX = 1L << 34;
+    public static final int BLOCK_HEADER_SIZE_MAX = 1024;
+    public static final long VLI_MAX = Long.MAX_VALUE;
+    public static final int VLI_SIZE_MAX = 9;
+
+    public static int getVLISize(long num) {
+        int size = 0;
+        do {
+            ++size;
+            num >>= 7;
+        } while (num != 0);
+
+        return size;
+    }
+}

app/src/main/java/org/tukaani/xz/delta/DeltaCoder.java

@@ -0,0 +1,27 @@
+/*
+ * DeltaCoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.delta;
+
+abstract class DeltaCoder {
+    static final int DISTANCE_MIN = 1;
+    static final int DISTANCE_MAX = 256;
+    static final int DISTANCE_MASK = DISTANCE_MAX - 1;
+
+    final int distance;
+    final byte[] history = new byte[DISTANCE_MAX];
+    int pos = 0;
+
+    DeltaCoder(int distance) {
+        if (distance < DISTANCE_MIN || distance > DISTANCE_MAX)
+            throw new IllegalArgumentException();
+
+        this.distance = distance;
+    }
+}

app/src/main/java/org/tukaani/xz/delta/DeltaDecoder.java

@@ -0,0 +1,24 @@
+/*
+ * DeltaDecoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.delta;
+
+public class DeltaDecoder extends DeltaCoder {
+    public DeltaDecoder(int distance) {
+        super(distance);
+    }
+
+    public void decode(byte[] buf, int off, int len) {
+        int end = off + len;
+        for (int i = off; i < end; ++i) {
+            buf[i] += history[(distance + pos) & DISTANCE_MASK];
+            history[pos-- & DISTANCE_MASK] = buf[i];
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/delta/DeltaEncoder.java

@@ -0,0 +1,24 @@
+/*
+ * DeltaEncoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.delta;
+
+public class DeltaEncoder extends DeltaCoder {
+    public DeltaEncoder(int distance) {
+        super(distance);
+    }
+
+    public void encode(byte[] in, int in_off, int len, byte[] out) {
+        for (int i = 0; i < len; ++i) {
+            byte tmp = history[(distance + pos) & DISTANCE_MASK];
+            history[pos-- & DISTANCE_MASK] = in[in_off + i];
+            out[i] = (byte)(in[in_off + i] - tmp);
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/index/BlockInfo.java

@@ -0,0 +1,38 @@
+/*
+ * BlockInfo
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.index;
+
+import org.tukaani.xz.common.StreamFlags;
+
+public class BlockInfo {
+    public int blockNumber = -1;
+    public long compressedOffset = -1;
+    public long uncompressedOffset = -1;
+    public long unpaddedSize = -1;
+    public long uncompressedSize = -1;
+
+    IndexDecoder index;
+
+    public BlockInfo(IndexDecoder indexOfFirstStream) {
+        index = indexOfFirstStream;
+    }
+
+    public int getCheckType() {
+        return index.getStreamFlags().checkType;
+    }
+
+    public boolean hasNext() {
+        return index.hasRecord(blockNumber + 1);
+    }
+
+    public void setNext() {
+        index.setBlockInfo(this, blockNumber + 1);
+    }
+}

app/src/main/java/org/tukaani/xz/index/IndexBase.java

@@ -0,0 +1,56 @@
+/*
+ * IndexBase
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.index;
+
+import org.tukaani.xz.common.Util;
+import org.tukaani.xz.XZIOException;
+
+abstract class IndexBase {
+    private final XZIOException invalidIndexException;
+    long blocksSum = 0;
+    long uncompressedSum = 0;
+    long indexListSize = 0;
+    long recordCount = 0;
+
+    IndexBase(XZIOException invalidIndexException) {
+        this.invalidIndexException = invalidIndexException;
+    }
+
+    private long getUnpaddedIndexSize() {
+        // Index Indicator + Number of Records + List of Records + CRC32
+        return 1 + Util.getVLISize(recordCount) + indexListSize + 4;
+    }
+
+    public long getIndexSize() {
+        return (getUnpaddedIndexSize() + 3) & ~3;
+    }
+
+    public long getStreamSize() {
+        return Util.STREAM_HEADER_SIZE + blocksSum + getIndexSize()
+                + Util.STREAM_HEADER_SIZE;
+    }
+
+    int getIndexPaddingSize() {
+        return (int)((4 - getUnpaddedIndexSize()) & 3);
+    }
+
+    void add(long unpaddedSize, long uncompressedSize) throws XZIOException {
+        blocksSum += (unpaddedSize + 3) & ~3;
+        uncompressedSum += uncompressedSize;
+        indexListSize += Util.getVLISize(unpaddedSize)
+                         + Util.getVLISize(uncompressedSize);
+        ++recordCount;
+
+        if (blocksSum < 0 || uncompressedSum < 0
+                || getIndexSize() > Util.BACKWARD_SIZE_MAX
+                || getStreamSize() < 0)
+            throw invalidIndexException;
+    }
+}

app/src/main/java/org/tukaani/xz/index/IndexDecoder.java

@@ -0,0 +1,223 @@
+/*
+ * IndexDecoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.index;
+
+import java.io.IOException;
+import java.io.EOFException;
+import java.util.zip.CheckedInputStream;
+import org.tukaani.xz.common.DecoderUtil;
+import org.tukaani.xz.common.StreamFlags;
+import org.tukaani.xz.SeekableInputStream;
+import org.tukaani.xz.CorruptedInputException;
+import org.tukaani.xz.MemoryLimitException;
+import org.tukaani.xz.UnsupportedOptionsException;
+
+public class IndexDecoder extends IndexBase {
+    private final StreamFlags streamFlags;
+    private final long streamPadding;
+    private final int memoryUsage;
+
+    // Unpadded Size and Uncompressed Size fields
+    private final long[] unpadded;
+    private final long[] uncompressed;
+
+    // Uncompressed size of the largest Block. It is used by
+    // SeekableXZInputStream to find out the largest Block of the .xz file.
+    private long largestBlockSize = 0;
+
+    // Offsets relative to the beginning of the .xz file. These are all zero
+    // for the first Stream in the file.
+    private int recordOffset = 0;
+    private long compressedOffset = 0;
+    private long uncompressedOffset = 0;
+
+    public IndexDecoder(SeekableInputStream in, StreamFlags streamFooterFlags,
+                        long streamPadding, int memoryLimit)
+            throws IOException {
+        super(new CorruptedInputException("XZ Index is corrupt"));
+        this.streamFlags = streamFooterFlags;
+        this.streamPadding = streamPadding;
+
+        // If endPos is exceeded before the CRC32 field has been decoded,
+        // the Index is corrupt.
+        long endPos = in.position() + streamFooterFlags.backwardSize - 4;
+
+        java.util.zip.CRC32 crc32 = new java.util.zip.CRC32();
+        CheckedInputStream inChecked = new CheckedInputStream(in, crc32);
+
+        // Index Indicator
+        if (inChecked.read() != 0x00)
+            throw new CorruptedInputException("XZ Index is corrupt");
+
+        try {
+            // Number of Records
+            long count = DecoderUtil.decodeVLI(inChecked);
+
+            // Catch Record counts that obviously too high to be valid.
+            // This test isn't exact because it ignores Index Indicator,
+            // Number of Records, and CRC32 fields, but this is good enough
+            // to catch the most obvious problems.
+            if (count >= streamFooterFlags.backwardSize / 2)
+                throw new CorruptedInputException("XZ Index is corrupt");
+
+            // If the Record count doesn't fit into an int, we cannot
+            // allocate the arrays to hold the Records.
+            if (count > Integer.MAX_VALUE)
+                throw new UnsupportedOptionsException("XZ Index has over "
+                        + Integer.MAX_VALUE + " Records");
+
+            // Calculate approximate memory requirements and check the
+            // memory usage limit.
+            memoryUsage = 1 + (int)((16L * count + 1023) / 1024);
+            if (memoryLimit >= 0 && memoryUsage > memoryLimit)
+                throw new MemoryLimitException(memoryUsage, memoryLimit);
+
+            // Allocate the arrays for the Records.
+            unpadded = new long[(int)count];
+            uncompressed = new long[(int)count];
+            int record = 0;
+
+            // Decode the Records.
+            for (int i = (int)count; i > 0; --i) {
+                // Get the next Record.
+                long unpaddedSize = DecoderUtil.decodeVLI(inChecked);
+                long uncompressedSize = DecoderUtil.decodeVLI(inChecked);
+
+                // Check that the input position stays sane. Since this is
+                // checked only once per loop iteration instead of for
+                // every input byte read, it's still possible that
+                // EOFException gets thrown with corrupt input.
+                if (in.position() > endPos)
+                    throw new CorruptedInputException("XZ Index is corrupt");
+
+                // Add the new Record.
+                unpadded[record] = blocksSum + unpaddedSize;
+                uncompressed[record] = uncompressedSum + uncompressedSize;
+                ++record;
+                super.add(unpaddedSize, uncompressedSize);
+                assert record == recordCount;
+
+                // Remember the uncompressed size of the largest Block.
+                if (largestBlockSize < uncompressedSize)
+                    largestBlockSize = uncompressedSize;
+            }
+        } catch (EOFException e) {
+            // EOFException is caught just in case a corrupt input causes
+            // DecoderUtil.decodeVLI to read too much at once.
+            throw new CorruptedInputException("XZ Index is corrupt");
+        }
+
+        // Validate that the size of the Index field matches
+        // Backward Size.
+        int indexPaddingSize = getIndexPaddingSize();
+        if (in.position() + indexPaddingSize != endPos)
+            throw new CorruptedInputException("XZ Index is corrupt");
+
+        // Index Padding
+        while (indexPaddingSize-- > 0)
+            if (inChecked.read() != 0x00)
+                throw new CorruptedInputException("XZ Index is corrupt");
+
+        // CRC32
+        long value = crc32.getValue();
+        for (int i = 0; i < 4; ++i)
+            if (((value >>> (i * 8)) & 0xFF) != in.read())
+                throw new CorruptedInputException("XZ Index is corrupt");
+    }
+
+    public void setOffsets(IndexDecoder prev) {
+        // NOTE: SeekableXZInputStream checks that the total number of Blocks
+        // in concatenated Streams fits into an int.
+        recordOffset = prev.recordOffset + (int)prev.recordCount;
+        compressedOffset = prev.compressedOffset
+                           + prev.getStreamSize() + prev.streamPadding;
+        assert (compressedOffset & 3) == 0;
+        uncompressedOffset = prev.uncompressedOffset + prev.uncompressedSum;
+    }
+
+    public int getMemoryUsage() {
+        return memoryUsage;
+    }
+
+    public StreamFlags getStreamFlags() {
+        return streamFlags;
+    }
+
+    public int getRecordCount() {
+        // It was already checked in the constructor that it fits into an int.
+        // Otherwise we couldn't have allocated the arrays.
+        return (int)recordCount;
+    }
+
+    public long getUncompressedSize() {
+        return uncompressedSum;
+    }
+
+    public long getLargestBlockSize() {
+        return largestBlockSize;
+    }
+
+    public boolean hasUncompressedOffset(long pos) {
+        return pos >= uncompressedOffset
+               && pos < uncompressedOffset + uncompressedSum;
+    }
+
+    public boolean hasRecord(int blockNumber) {
+        return blockNumber >= recordOffset
+               && blockNumber < recordOffset + recordCount;
+    }
+
+    public void locateBlock(BlockInfo info, long target) {
+        assert target >= uncompressedOffset;
+        target -= uncompressedOffset;
+        assert target < uncompressedSum;
+
+        int left = 0;
+        int right = unpadded.length - 1;
+
+        while (left < right) {
+            int i = left + (right - left) / 2;
+
+            if (uncompressed[i] <= target)
+                left = i + 1;
+            else
+                right = i;
+        }
+
+        setBlockInfo(info, recordOffset + left);
+    }
+
+    public void setBlockInfo(BlockInfo info, int blockNumber) {
+        // The caller has checked that the given Block number is inside
+        // this Index.
+        assert blockNumber >= recordOffset;
+        assert blockNumber - recordOffset < recordCount;
+
+        info.index = this;
+        info.blockNumber = blockNumber;
+
+        int pos = blockNumber - recordOffset;
+
+        if (pos == 0) {
+            info.compressedOffset = 0;
+            info.uncompressedOffset = 0;
+        } else {
+            info.compressedOffset = (unpadded[pos - 1] + 3) & ~3;
+            info.uncompressedOffset = uncompressed[pos - 1];
+        }
+
+        info.unpaddedSize = unpadded[pos] - info.compressedOffset;
+        info.uncompressedSize = uncompressed[pos] - info.uncompressedOffset;
+
+        info.compressedOffset += compressedOffset
+                                 + DecoderUtil.STREAM_HEADER_SIZE;
+        info.uncompressedOffset += uncompressedOffset;
+    }
+}

app/src/main/java/org/tukaani/xz/index/IndexEncoder.java

@@ -0,0 +1,59 @@
+/*
+ * IndexEncoder
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.index;
+
+import java.io.OutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.zip.CheckedOutputStream;
+import org.tukaani.xz.common.EncoderUtil;
+import org.tukaani.xz.XZIOException;
+
+public class IndexEncoder extends IndexBase {
+    private final ArrayList<IndexRecord> records
+            = new ArrayList<IndexRecord>();
+
+    public IndexEncoder() {
+        super(new XZIOException("XZ Stream or its Index has grown too big"));
+    }
+
+    public void add(long unpaddedSize, long uncompressedSize)
+            throws XZIOException {
+        super.add(unpaddedSize, uncompressedSize);
+        records.add(new IndexRecord(unpaddedSize, uncompressedSize));
+    }
+
+    public void encode(OutputStream out) throws IOException {
+        java.util.zip.CRC32 crc32 = new java.util.zip.CRC32();
+        CheckedOutputStream outChecked = new CheckedOutputStream(out, crc32);
+
+        // Index Indicator
+        outChecked.write(0x00);
+
+        // Number of Records
+        EncoderUtil.encodeVLI(outChecked, recordCount);
+
+        // List of Records
+        for (IndexRecord record : records) {
+            EncoderUtil.encodeVLI(outChecked, record.unpadded);
+            EncoderUtil.encodeVLI(outChecked, record.uncompressed);
+        }
+
+        // Index Padding
+        for (int i = getIndexPaddingSize(); i > 0; --i)
+            outChecked.write(0x00);
+
+        // CRC32
+        long value = crc32.getValue();
+        for (int i = 0; i < 4; ++i)
+            out.write((byte)(value >>> (i * 8)));
+    }
+}

app/src/main/java/org/tukaani/xz/index/IndexHash.java

@@ -0,0 +1,98 @@
+/*
+ * IndexHash
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.index;
+
+import java.io.InputStream;
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.zip.CheckedInputStream;
+import org.tukaani.xz.common.DecoderUtil;
+import org.tukaani.xz.XZIOException;
+import org.tukaani.xz.CorruptedInputException;
+
+public class IndexHash extends IndexBase {
+    private org.tukaani.xz.check.Check hash;
+
+    public IndexHash() {
+        super(new CorruptedInputException());
+
+        try {
+            hash = new org.tukaani.xz.check.SHA256();
+        } catch (java.security.NoSuchAlgorithmException e) {
+            hash = new org.tukaani.xz.check.CRC32();
+        }
+    }
+
+    public void add(long unpaddedSize, long uncompressedSize)
+            throws XZIOException {
+        super.add(unpaddedSize, uncompressedSize);
+
+        ByteBuffer buf = ByteBuffer.allocate(2 * 8);
+        buf.putLong(unpaddedSize);
+        buf.putLong(uncompressedSize);
+        hash.update(buf.array());
+    }
+
+    public void validate(InputStream in) throws IOException {
+        // Index Indicator (0x00) has already been read by BlockInputStream
+        // so add 0x00 to the CRC32 here.
+        java.util.zip.CRC32 crc32 = new java.util.zip.CRC32();
+        crc32.update('\0');
+        CheckedInputStream inChecked = new CheckedInputStream(in, crc32);
+
+        // Get and validate the Number of Records field.
+        // If Block Header Size was corrupt and became Index Indicator,
+        // this error would actually be about corrupt Block Header.
+        // This is why the error message mentions both possibilities.
+        long storedRecordCount = DecoderUtil.decodeVLI(inChecked);
+        if (storedRecordCount != recordCount)
+            throw new CorruptedInputException(
+                    "XZ Block Header or the start of XZ Index is corrupt");
+
+        // Decode and hash the Index field and compare it to
+        // the hash value calculated from the decoded Blocks.
+        IndexHash stored = new IndexHash();
+        for (long i = 0; i < recordCount; ++i) {
+            long unpaddedSize = DecoderUtil.decodeVLI(inChecked);
+            long uncompressedSize = DecoderUtil.decodeVLI(inChecked);
+
+            try {
+                stored.add(unpaddedSize, uncompressedSize);
+            } catch (XZIOException e) {
+                throw new CorruptedInputException("XZ Index is corrupt");
+            }
+
+            if (stored.blocksSum > blocksSum
+                    || stored.uncompressedSum > uncompressedSum
+                    || stored.indexListSize > indexListSize)
+                throw new CorruptedInputException("XZ Index is corrupt");
+        }
+
+        if (stored.blocksSum != blocksSum
+                || stored.uncompressedSum != uncompressedSum
+                || stored.indexListSize != indexListSize
+                || !Arrays.equals(stored.hash.finish(), hash.finish()))
+            throw new CorruptedInputException("XZ Index is corrupt");
+
+        // Index Padding
+        DataInputStream inData = new DataInputStream(inChecked);
+        for (int i = getIndexPaddingSize(); i > 0; --i)
+            if (inData.readUnsignedByte() != 0x00)
+                throw new CorruptedInputException("XZ Index is corrupt");
+
+        // CRC32
+        long value = crc32.getValue();
+        for (int i = 0; i < 4; ++i)
+            if (((value >>> (i * 8)) & 0xFF) != inData.readUnsignedByte())
+                throw new CorruptedInputException("XZ Index is corrupt");
+    }
+}

app/src/main/java/org/tukaani/xz/index/IndexRecord.java

@@ -0,0 +1,20 @@
+/*
+ * IndexRecord
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.index;
+
+class IndexRecord {
+    final long unpadded;
+    final long uncompressed;
+
+    IndexRecord(long unpadded, long uncompressed) {
+        this.unpadded = unpadded;
+        this.uncompressed = uncompressed;
+    }
+}

app/src/main/java/org/tukaani/xz/lz/BT4.java

@@ -0,0 +1,265 @@
+/*
+ * Binary Tree match finder with 2-, 3-, and 4-byte hashing
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lz;
+
+import org.tukaani.xz.ArrayCache;
+
+final class BT4 extends LZEncoder {
+    private final Hash234 hash;
+    private final int[] tree;
+    private final Matches matches;
+    private final int depthLimit;
+
+    private final int cyclicSize;
+    private int cyclicPos = -1;
+    private int lzPos;
+
+    static int getMemoryUsage(int dictSize) {
+        return Hash234.getMemoryUsage(dictSize) + dictSize / (1024 / 8) + 10;
+    }
+
+    BT4(int dictSize, int beforeSizeMin, int readAheadMax,
+            int niceLen, int matchLenMax, int depthLimit,
+            ArrayCache arrayCache) {
+        super(dictSize, beforeSizeMin, readAheadMax, niceLen, matchLenMax,
+              arrayCache);
+
+        cyclicSize = dictSize + 1;
+        lzPos = cyclicSize;
+
+        hash = new Hash234(dictSize, arrayCache);
+        tree = arrayCache.getIntArray(cyclicSize * 2, false);
+
+        // Substracting 1 because the shortest match that this match
+        // finder can find is 2 bytes, so there's no need to reserve
+        // space for one-byte matches.
+        matches = new Matches(niceLen - 1);
+
+        this.depthLimit = depthLimit > 0 ? depthLimit : 16 + niceLen / 2;
+    }
+
+    public void putArraysToCache(ArrayCache arrayCache) {
+        arrayCache.putArray(tree);
+        hash.putArraysToCache(arrayCache);
+        super.putArraysToCache(arrayCache);
+    }
+
+    private int movePos() {
+        int avail = movePos(niceLen, 4);
+
+        if (avail != 0) {
+            if (++lzPos == Integer.MAX_VALUE) {
+                int normalizationOffset = Integer.MAX_VALUE - cyclicSize;
+                hash.normalize(normalizationOffset);
+                normalize(tree, cyclicSize * 2, normalizationOffset);
+                lzPos -= normalizationOffset;
+            }
+
+            if (++cyclicPos == cyclicSize)
+                cyclicPos = 0;
+        }
+
+        return avail;
+    }
+
+    public Matches getMatches() {
+        matches.count = 0;
+
+        int matchLenLimit = matchLenMax;
+        int niceLenLimit = niceLen;
+        int avail = movePos();
+
+        if (avail < matchLenLimit) {
+            if (avail == 0)
+                return matches;
+
+            matchLenLimit = avail;
+            if (niceLenLimit > avail)
+                niceLenLimit = avail;
+        }
+
+        hash.calcHashes(buf, readPos);
+        int delta2 = lzPos - hash.getHash2Pos();
+        int delta3 = lzPos - hash.getHash3Pos();
+        int currentMatch = hash.getHash4Pos();
+        hash.updateTables(lzPos);
+
+        int lenBest = 0;
+
+        // See if the hash from the first two bytes found a match.
+        // The hashing algorithm guarantees that if the first byte
+        // matches, also the second byte does, so there's no need to
+        // test the second byte.
+        if (delta2 < cyclicSize && buf[readPos - delta2] == buf[readPos]) {
+            lenBest = 2;
+            matches.len[0] = 2;
+            matches.dist[0] = delta2 - 1;
+            matches.count = 1;
+        }
+
+        // See if the hash from the first three bytes found a match that
+        // is different from the match possibly found by the two-byte hash.
+        // Also here the hashing algorithm guarantees that if the first byte
+        // matches, also the next two bytes do.
+        if (delta2 != delta3 && delta3 < cyclicSize
+                && buf[readPos - delta3] == buf[readPos]) {
+            lenBest = 3;
+            matches.dist[matches.count++] = delta3 - 1;
+            delta2 = delta3;
+        }
+
+        // If a match was found, see how long it is.
+        if (matches.count > 0) {
+            while (lenBest < matchLenLimit && buf[readPos + lenBest - delta2]
+                                              == buf[readPos + lenBest])
+                ++lenBest;
+
+            matches.len[matches.count - 1] = lenBest;
+
+            // Return if it is long enough (niceLen or reached the end of
+            // the dictionary).
+            if (lenBest >= niceLenLimit) {
+                skip(niceLenLimit, currentMatch);
+                return matches;
+            }
+        }
+
+        // Long enough match wasn't found so easily. Look for better matches
+        // from the binary tree.
+        if (lenBest < 3)
+            lenBest = 3;
+
+        int depth = depthLimit;
+
+        int ptr0 = (cyclicPos << 1) + 1;
+        int ptr1 = cyclicPos << 1;
+        int len0 = 0;
+        int len1 = 0;
+
+        while (true) {
+            int delta = lzPos - currentMatch;
+
+            // Return if the search depth limit has been reached or
+            // if the distance of the potential match exceeds the
+            // dictionary size.
+            if (depth-- == 0 || delta >= cyclicSize) {
+                tree[ptr0] = 0;
+                tree[ptr1] = 0;
+                return matches;
+            }
+
+            int pair = (cyclicPos - delta
+                        + (delta > cyclicPos ? cyclicSize : 0)) << 1;
+            int len = Math.min(len0, len1);
+
+            if (buf[readPos + len - delta] == buf[readPos + len]) {
+                while (++len < matchLenLimit)
+                    if (buf[readPos + len - delta] != buf[readPos + len])
+                        break;
+
+                if (len > lenBest) {
+                    lenBest = len;
+                    matches.len[matches.count] = len;
+                    matches.dist[matches.count] = delta - 1;
+                    ++matches.count;
+
+                    if (len >= niceLenLimit) {
+                        tree[ptr1] = tree[pair];
+                        tree[ptr0] = tree[pair + 1];
+                        return matches;
+                    }
+                }
+            }
+
+            if ((buf[readPos + len - delta] & 0xFF)
+                    < (buf[readPos + len] & 0xFF)) {
+                tree[ptr1] = currentMatch;
+                ptr1 = pair + 1;
+                currentMatch = tree[ptr1];
+                len1 = len;
+            } else {
+                tree[ptr0] = currentMatch;
+                ptr0 = pair;
+                currentMatch = tree[ptr0];
+                len0 = len;
+            }
+        }
+    }
+
+    private void skip(int niceLenLimit, int currentMatch) {
+        int depth = depthLimit;
+
+        int ptr0 = (cyclicPos << 1) + 1;
+        int ptr1 = cyclicPos << 1;
+        int len0 = 0;
+        int len1 = 0;
+
+        while (true) {
+            int delta = lzPos - currentMatch;
+
+            if (depth-- == 0 || delta >= cyclicSize) {
+                tree[ptr0] = 0;
+                tree[ptr1] = 0;
+                return;
+            }
+
+            int pair = (cyclicPos - delta
+                        + (delta > cyclicPos ? cyclicSize : 0)) << 1;
+            int len = Math.min(len0, len1);
+
+            if (buf[readPos + len - delta] == buf[readPos + len]) {
+                // No need to look for longer matches than niceLenLimit
+                // because we only are updating the tree, not returning
+                // matches found to the caller.
+                do {
+                    if (++len == niceLenLimit) {
+                        tree[ptr1] = tree[pair];
+                        tree[ptr0] = tree[pair + 1];
+                        return;
+                    }
+                } while (buf[readPos + len - delta] == buf[readPos + len]);
+            }
+
+            if ((buf[readPos + len - delta] & 0xFF)
+                    < (buf[readPos + len] & 0xFF)) {
+                tree[ptr1] = currentMatch;
+                ptr1 = pair + 1;
+                currentMatch = tree[ptr1];
+                len1 = len;
+            } else {
+                tree[ptr0] = currentMatch;
+                ptr0 = pair;
+                currentMatch = tree[ptr0];
+                len0 = len;
+            }
+        }
+    }
+
+    public void skip(int len) {
+        while (len-- > 0) {
+            int niceLenLimit = niceLen;
+            int avail = movePos();
+
+            if (avail < niceLenLimit) {
+                if (avail == 0)
+                    continue;
+
+                niceLenLimit = avail;
+            }
+
+            hash.calcHashes(buf, readPos);
+            int currentMatch = hash.getHash4Pos();
+            hash.updateTables(lzPos);
+
+            skip(niceLenLimit, currentMatch);
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/lz/CRC32Hash.java

@@ -0,0 +1,35 @@
+/*
+ * CRC32Hash
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lz;
+
+/**
+ * Provides a CRC32 table using the polynomial from IEEE 802.3.
+ */
+class CRC32Hash {
+    private static final int CRC32_POLY = 0xEDB88320;
+
+    static final int[] crcTable = new int[256];
+
+    static {
+        for (int i = 0; i < 256; ++i) {
+            int r = i;
+
+            for (int j = 0; j < 8; ++j) {
+                if ((r & 1) != 0)
+                    r = (r >>> 1) ^ CRC32_POLY;
+                else
+                    r >>>= 1;
+            }
+
+            crcTable[i] = r;
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/lz/HC4.java

@@ -0,0 +1,210 @@
+/*
+ * Hash Chain match finder with 2-, 3-, and 4-byte hashing
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lz;
+
+import org.tukaani.xz.ArrayCache;
+
+final class HC4 extends LZEncoder {
+    private final Hash234 hash;
+    private final int[] chain;
+    private final Matches matches;
+    private final int depthLimit;
+
+    private final int cyclicSize;
+    private int cyclicPos = -1;
+    private int lzPos;
+
+    /**
+     * Gets approximate memory usage of the match finder as kibibytes.
+     */
+    static int getMemoryUsage(int dictSize) {
+        return Hash234.getMemoryUsage(dictSize) + dictSize / (1024 / 4) + 10;
+    }
+
+    /**
+     * Creates a new LZEncoder with the HC4 match finder.
+     * See <code>LZEncoder.getInstance</code> for parameter descriptions.
+     */
+    HC4(int dictSize, int beforeSizeMin, int readAheadMax,
+            int niceLen, int matchLenMax, int depthLimit,
+            ArrayCache arrayCache) {
+        super(dictSize, beforeSizeMin, readAheadMax, niceLen, matchLenMax,
+              arrayCache);
+
+        hash = new Hash234(dictSize, arrayCache);
+
+        // +1 because we need dictSize bytes of history + the current byte.
+        cyclicSize = dictSize + 1;
+        chain = arrayCache.getIntArray(cyclicSize, false);
+        lzPos = cyclicSize;
+
+        // Substracting 1 because the shortest match that this match
+        // finder can find is 2 bytes, so there's no need to reserve
+        // space for one-byte matches.
+        matches = new Matches(niceLen - 1);
+
+        // Use a default depth limit if no other value was specified.
+        // The default is just something based on experimentation;
+        // it's nothing magic.
+        this.depthLimit = (depthLimit > 0) ? depthLimit : 4 + niceLen / 4;
+    }
+
+    public void putArraysToCache(ArrayCache arrayCache) {
+        arrayCache.putArray(chain);
+        hash.putArraysToCache(arrayCache);
+        super.putArraysToCache(arrayCache);
+    }
+
+    /**
+     * Moves to the next byte, checks that there is enough available space,
+     * and possibly normalizes the hash tables and the hash chain.
+     *
+     * @return      number of bytes available, including the current byte
+     */
+    private int movePos() {
+        int avail = movePos(4, 4);
+
+        if (avail != 0) {
+            if (++lzPos == Integer.MAX_VALUE) {
+                int normalizationOffset = Integer.MAX_VALUE - cyclicSize;
+                hash.normalize(normalizationOffset);
+                normalize(chain, cyclicSize, normalizationOffset);
+                lzPos -= normalizationOffset;
+            }
+
+            if (++cyclicPos == cyclicSize)
+                cyclicPos = 0;
+        }
+
+        return avail;
+    }
+
+    public Matches getMatches() {
+        matches.count = 0;
+        int matchLenLimit = matchLenMax;
+        int niceLenLimit = niceLen;
+        int avail = movePos();
+
+        if (avail < matchLenLimit) {
+            if (avail == 0)
+                return matches;
+
+            matchLenLimit = avail;
+            if (niceLenLimit > avail)
+                niceLenLimit = avail;
+        }
+
+        hash.calcHashes(buf, readPos);
+        int delta2 = lzPos - hash.getHash2Pos();
+        int delta3 = lzPos - hash.getHash3Pos();
+        int currentMatch = hash.getHash4Pos();
+        hash.updateTables(lzPos);
+
+        chain[cyclicPos] = currentMatch;
+
+        int lenBest = 0;
+
+        // See if the hash from the first two bytes found a match.
+        // The hashing algorithm guarantees that if the first byte
+        // matches, also the second byte does, so there's no need to
+        // test the second byte.
+        if (delta2 < cyclicSize && buf[readPos - delta2] == buf[readPos]) {
+            lenBest = 2;
+            matches.len[0] = 2;
+            matches.dist[0] = delta2 - 1;
+            matches.count = 1;
+        }
+
+        // See if the hash from the first three bytes found a match that
+        // is different from the match possibly found by the two-byte hash.
+        // Also here the hashing algorithm guarantees that if the first byte
+        // matches, also the next two bytes do.
+        if (delta2 != delta3 && delta3 < cyclicSize
+                && buf[readPos - delta3] == buf[readPos]) {
+            lenBest = 3;
+            matches.dist[matches.count++] = delta3 - 1;
+            delta2 = delta3;
+        }
+
+        // If a match was found, see how long it is.
+        if (matches.count > 0) {
+            while (lenBest < matchLenLimit && buf[readPos + lenBest - delta2]
+                                              == buf[readPos + lenBest])
+                ++lenBest;
+
+            matches.len[matches.count - 1] = lenBest;
+
+            // Return if it is long enough (niceLen or reached the end of
+            // the dictionary).
+            if (lenBest >= niceLenLimit)
+                return matches;
+        }
+
+        // Long enough match wasn't found so easily. Look for better matches
+        // from the hash chain.
+        if (lenBest < 3)
+            lenBest = 3;
+
+        int depth = depthLimit;
+
+        while (true) {
+            int delta = lzPos - currentMatch;
+
+            // Return if the search depth limit has been reached or
+            // if the distance of the potential match exceeds the
+            // dictionary size.
+            if (depth-- == 0 || delta >= cyclicSize)
+                return matches;
+
+            currentMatch = chain[cyclicPos - delta
+                                 + (delta > cyclicPos ? cyclicSize : 0)];
+
+            // Test the first byte and the first new byte that would give us
+            // a match that is at least one byte longer than lenBest. This
+            // too short matches get quickly skipped.
+            if (buf[readPos + lenBest - delta] == buf[readPos + lenBest]
+                    && buf[readPos - delta] == buf[readPos]) {
+                // Calculate the length of the match.
+                int len = 0;
+                while (++len < matchLenLimit)
+                    if (buf[readPos + len - delta] != buf[readPos + len])
+                        break;
+
+                // Use the match if and only if it is better than the longest
+                // match found so far.
+                if (len > lenBest) {
+                    lenBest = len;
+                    matches.len[matches.count] = len;
+                    matches.dist[matches.count] = delta - 1;
+                    ++matches.count;
+
+                    // Return if it is long enough (niceLen or reached the
+                    // end of the dictionary).
+                    if (len >= niceLenLimit)
+                        return matches;
+                }
+            }
+        }
+    }
+
+    public void skip(int len) {
+        assert len >= 0;
+
+        while (len-- > 0) {
+            if (movePos() != 0) {
+                // Update the hash chain and hash tables.
+                hash.calcHashes(buf, readPos);
+                chain[cyclicPos] = hash.getHash4Pos();
+                hash.updateTables(lzPos);
+            }
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/lz/Hash234.java

@@ -0,0 +1,102 @@
+/*
+ * 2-, 3-, and 4-byte hashing
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lz;
+
+import org.tukaani.xz.ArrayCache;
+
+final class Hash234 extends CRC32Hash {
+    private static final int HASH_2_SIZE = 1 << 10;
+    private static final int HASH_2_MASK = HASH_2_SIZE - 1;
+
+    private static final int HASH_3_SIZE = 1 << 16;
+    private static final int HASH_3_MASK = HASH_3_SIZE - 1;
+
+    private final int hash4Mask;
+
+    private final int[] hash2Table;
+    private final int[] hash3Table;
+    private final int[] hash4Table;
+    private final int hash4Size;
+
+    private int hash2Value = 0;
+    private int hash3Value = 0;
+    private int hash4Value = 0;
+
+    static int getHash4Size(int dictSize) {
+        int h = dictSize - 1;
+        h |= h >>> 1;
+        h |= h >>> 2;
+        h |= h >>> 4;
+        h |= h >>> 8;
+        h >>>= 1;
+        h |= 0xFFFF;
+        if (h > (1 << 24))
+            h >>>= 1;
+
+        return h + 1;
+    }
+
+    static int getMemoryUsage(int dictSize) {
+        // Sizes of the hash arrays + a little extra
+        return (HASH_2_SIZE + HASH_3_SIZE + getHash4Size(dictSize))
+               / (1024 / 4) + 4;
+    }
+
+    Hash234(int dictSize, ArrayCache arrayCache) {
+        hash2Table = arrayCache.getIntArray(HASH_2_SIZE, true);
+        hash3Table = arrayCache.getIntArray(HASH_3_SIZE, true);
+
+        hash4Size = getHash4Size(dictSize);
+        hash4Table = arrayCache.getIntArray(hash4Size, true);
+        hash4Mask = hash4Size - 1;
+    }
+
+    void putArraysToCache(ArrayCache arrayCache) {
+        arrayCache.putArray(hash4Table);
+        arrayCache.putArray(hash3Table);
+        arrayCache.putArray(hash2Table);
+    }
+
+    void calcHashes(byte[] buf, int off) {
+        int temp = crcTable[buf[off] & 0xFF] ^ (buf[off + 1] & 0xFF);
+        hash2Value = temp & HASH_2_MASK;
+
+        temp ^= (buf[off + 2] & 0xFF) << 8;
+        hash3Value = temp & HASH_3_MASK;
+
+        temp ^= crcTable[buf[off + 3] & 0xFF] << 5;
+        hash4Value = temp & hash4Mask;
+    }
+
+    int getHash2Pos() {
+        return hash2Table[hash2Value];
+    }
+
+    int getHash3Pos() {
+        return hash3Table[hash3Value];
+    }
+
+    int getHash4Pos() {
+        return hash4Table[hash4Value];
+    }
+
+    void updateTables(int pos) {
+        hash2Table[hash2Value] = pos;
+        hash3Table[hash3Value] = pos;
+        hash4Table[hash4Value] = pos;
+    }
+
+    void normalize(int normalizationOffset) {
+        LZEncoder.normalize(hash2Table, HASH_2_SIZE, normalizationOffset);
+        LZEncoder.normalize(hash3Table, HASH_3_SIZE, normalizationOffset);
+        LZEncoder.normalize(hash4Table, hash4Size, normalizationOffset);
+    }
+}

app/src/main/java/org/tukaani/xz/lz/LZDecoder.java

@@ -0,0 +1,162 @@
+/*
+ * LZDecoder
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lz;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+import org.tukaani.xz.ArrayCache;
+import org.tukaani.xz.CorruptedInputException;
+
+public final class LZDecoder {
+    private final byte[] buf;
+    private final int bufSize; // To avoid buf.length with an array-cached buf.
+    private int start = 0;
+    private int pos = 0;
+    private int full = 0;
+    private int limit = 0;
+    private int pendingLen = 0;
+    private int pendingDist = 0;
+
+    public LZDecoder(int dictSize, byte[] presetDict, ArrayCache arrayCache) {
+        bufSize = dictSize;
+        buf = arrayCache.getByteArray(bufSize, false);
+
+        if (presetDict != null) {
+            pos = Math.min(presetDict.length, dictSize);
+            full = pos;
+            start = pos;
+            System.arraycopy(presetDict, presetDict.length - pos, buf, 0, pos);
+        }
+    }
+
+    public void putArraysToCache(ArrayCache arrayCache) {
+        arrayCache.putArray(buf);
+    }
+
+    public void reset() {
+        start = 0;
+        pos = 0;
+        full = 0;
+        limit = 0;
+        buf[bufSize - 1] = 0x00;
+    }
+
+    public void setLimit(int outMax) {
+        if (bufSize - pos <= outMax)
+            limit = bufSize;
+        else
+            limit = pos + outMax;
+    }
+
+    public boolean hasSpace() {
+        return pos < limit;
+    }
+
+    public boolean hasPending() {
+        return pendingLen > 0;
+    }
+
+    public int getPos() {
+        return pos;
+    }
+
+    public int getByte(int dist) {
+        int offset = pos - dist - 1;
+        if (dist >= pos)
+            offset += bufSize;
+
+        return buf[offset] & 0xFF;
+    }
+
+    public void putByte(byte b) {
+        buf[pos++] = b;
+
+        if (full < pos)
+            full = pos;
+    }
+
+    public void repeat(int dist, int len) throws IOException {
+        if (dist < 0 || dist >= full)
+            throw new CorruptedInputException();
+
+        int left = Math.min(limit - pos, len);
+        pendingLen = len - left;
+        pendingDist = dist;
+
+        int back = pos - dist - 1;
+        if (back < 0) {
+            // The distance wraps around to the end of the cyclic dictionary
+            // buffer. We cannot get here if the dictionary isn't full.
+            assert full == bufSize;
+            back += bufSize;
+
+            // Here we will never copy more than dist + 1 bytes and
+            // so the copying won't repeat from its own output.
+            // Thus, we can always use arraycopy safely.
+            int copySize = Math.min(bufSize - back, left);
+            assert copySize <= dist + 1;
+
+            System.arraycopy(buf, back, buf, pos, copySize);
+            pos += copySize;
+            back = 0;
+            left -= copySize;
+
+            if (left == 0)
+                return;
+        }
+
+        assert back < pos;
+        assert left > 0;
+
+        do {
+            // Determine the number of bytes to copy on this loop iteration:
+            // copySize is set so that the source and destination ranges
+            // don't overlap. If "left" is large enough, the destination
+            // range will start right after the last byte of the source
+            // range. This way we don't need to advance "back" which
+            // allows the next iteration of this loop to copy (up to)
+            // twice the number of bytes.
+            int copySize = Math.min(left, pos - back);
+            System.arraycopy(buf, back, buf, pos, copySize);
+            pos += copySize;
+            left -= copySize;
+        } while (left > 0);
+
+        if (full < pos)
+            full = pos;
+    }
+
+    public void repeatPending() throws IOException {
+        if (pendingLen > 0)
+            repeat(pendingDist, pendingLen);
+    }
+
+    public void copyUncompressed(DataInputStream inData, int len)
+            throws IOException {
+        int copySize = Math.min(bufSize - pos, len);
+        inData.readFully(buf, pos, copySize);
+        pos += copySize;
+
+        if (full < pos)
+            full = pos;
+    }
+
+    public int flush(byte[] out, int outOff) {
+        int copySize = pos - start;
+        if (pos == bufSize)
+            pos = 0;
+
+        System.arraycopy(buf, start, out, outOff, copySize);
+        start = pos;
+
+        return copySize;
+    }
+}

app/src/main/java/org/tukaani/xz/lz/LZEncoder.java

@@ -0,0 +1,428 @@
+/*
+ * LZEncoder
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lz;
+
+import java.io.OutputStream;
+import java.io.IOException;
+import org.tukaani.xz.ArrayCache;
+
+public abstract class LZEncoder {
+    public static final int MF_HC4 = 0x04;
+    public static final int MF_BT4 = 0x14;
+
+    /**
+     * Number of bytes to keep available before the current byte
+     * when moving the LZ window.
+     */
+    private final int keepSizeBefore;
+
+    /**
+     * Number of bytes that must be available, the current byte included,
+     * to make hasEnoughData return true. Flushing and finishing are
+     * naturally exceptions to this since there cannot be any data after
+     * the end of the uncompressed input.
+     */
+    private final int keepSizeAfter;
+
+    final int matchLenMax;
+    final int niceLen;
+
+    final byte[] buf;
+    final int bufSize; // To avoid buf.length with an array-cached buf.
+
+    int readPos = -1;
+    private int readLimit = -1;
+    private boolean finishing = false;
+    private int writePos = 0;
+    private int pendingSize = 0;
+
+    static void normalize(int[] positions, int positionsCount,
+                          int normalizationOffset) {
+        for (int i = 0; i < positionsCount; ++i) {
+            if (positions[i] <= normalizationOffset)
+                positions[i] = 0;
+            else
+                positions[i] -= normalizationOffset;
+        }
+    }
+
+    /**
+     * Gets the size of the LZ window buffer that needs to be allocated.
+     */
+    private static int getBufSize(
+            int dictSize, int extraSizeBefore, int extraSizeAfter,
+            int matchLenMax) {
+        int keepSizeBefore = extraSizeBefore + dictSize;
+        int keepSizeAfter = extraSizeAfter + matchLenMax;
+        int reserveSize = Math.min(dictSize / 2 + (256 << 10), 512 << 20);
+        return keepSizeBefore + keepSizeAfter + reserveSize;
+    }
+
+    /**
+     * Gets approximate memory usage of the LZEncoder base structure and
+     * the match finder as kibibytes.
+     */
+    public static int getMemoryUsage(
+            int dictSize, int extraSizeBefore, int extraSizeAfter,
+            int matchLenMax, int mf) {
+        // Buffer size + a little extra
+        int m = getBufSize(dictSize, extraSizeBefore, extraSizeAfter,
+                           matchLenMax) / 1024 + 10;
+
+        switch (mf) {
+            case MF_HC4:
+                m += HC4.getMemoryUsage(dictSize);
+                break;
+
+            case MF_BT4:
+                m += BT4.getMemoryUsage(dictSize);
+                break;
+
+            default:
+                throw new IllegalArgumentException();
+        }
+
+        return m;
+    }
+
+    /**
+     * Creates a new LZEncoder.
+     * <p>
+     * @param       dictSize    dictionary size
+     *
+     * @param       extraSizeBefore
+     *                          number of bytes to keep available in the
+     *                          history in addition to dictSize
+     *
+     * @param       extraSizeAfter
+     *                          number of bytes that must be available
+     *                          after current position + matchLenMax
+     *
+     * @param       niceLen     if a match of at least <code>niceLen</code>
+     *                          bytes is found, be happy with it and don't
+     *                          stop looking for longer matches
+     *
+     * @param       matchLenMax don't test for matches longer than
+     *                          <code>matchLenMax</code> bytes
+     *
+     * @param       mf          match finder ID
+     *
+     * @param       depthLimit  match finder search depth limit
+     */
+    public static LZEncoder getInstance(
+            int dictSize, int extraSizeBefore, int extraSizeAfter,
+            int niceLen, int matchLenMax, int mf, int depthLimit,
+            ArrayCache arrayCache) {
+        switch (mf) {
+            case MF_HC4:
+                return new HC4(dictSize, extraSizeBefore, extraSizeAfter,
+                               niceLen, matchLenMax, depthLimit, arrayCache);
+
+            case MF_BT4:
+                return new BT4(dictSize, extraSizeBefore, extraSizeAfter,
+                               niceLen, matchLenMax, depthLimit, arrayCache);
+        }
+
+        throw new IllegalArgumentException();
+    }
+
+    /**
+     * Creates a new LZEncoder. See <code>getInstance</code>.
+     */
+    LZEncoder(int dictSize, int extraSizeBefore, int extraSizeAfter,
+              int niceLen, int matchLenMax, ArrayCache arrayCache) {
+        bufSize = getBufSize(dictSize, extraSizeBefore, extraSizeAfter,
+                             matchLenMax);
+        buf = arrayCache.getByteArray(bufSize, false);
+
+        keepSizeBefore = extraSizeBefore + dictSize;
+        keepSizeAfter = extraSizeAfter + matchLenMax;
+
+        this.matchLenMax = matchLenMax;
+        this.niceLen = niceLen;
+    }
+
+    public void putArraysToCache(ArrayCache arrayCache) {
+        arrayCache.putArray(buf);
+    }
+
+    /**
+     * Sets a preset dictionary. If a preset dictionary is wanted, this
+     * function must be called immediately after creating the LZEncoder
+     * before any data has been encoded.
+     */
+    public void setPresetDict(int dictSize, byte[] presetDict) {
+        assert !isStarted();
+        assert writePos == 0;
+
+        if (presetDict != null) {
+            // If the preset dictionary buffer is bigger than the dictionary
+            // size, copy only the tail of the preset dictionary.
+            int copySize = Math.min(presetDict.length, dictSize);
+            int offset = presetDict.length - copySize;
+            System.arraycopy(presetDict, offset, buf, 0, copySize);
+            writePos += copySize;
+            skip(copySize);
+        }
+    }
+
+    /**
+     * Moves data from the end of the buffer to the beginning, discarding
+     * old data and making space for new input.
+     */
+    private void moveWindow() {
+        // Align the move to a multiple of 16 bytes. LZMA2 needs this
+        // because it uses the lowest bits from readPos to get the
+        // alignment of the uncompressed data.
+        int moveOffset = (readPos + 1 - keepSizeBefore) & ~15;
+        int moveSize = writePos - moveOffset;
+        System.arraycopy(buf, moveOffset, buf, 0, moveSize);
+
+        readPos -= moveOffset;
+        readLimit -= moveOffset;
+        writePos -= moveOffset;
+    }
+
+    /**
+     * Copies new data into the LZEncoder's buffer.
+     */
+    public int fillWindow(byte[] in, int off, int len) {
+        assert !finishing;
+
+        // Move the sliding window if needed.
+        if (readPos >= bufSize - keepSizeAfter)
+            moveWindow();
+
+        // Try to fill the dictionary buffer. If it becomes full,
+        // some of the input bytes may be left unused.
+        if (len > bufSize - writePos)
+            len = bufSize - writePos;
+
+        System.arraycopy(in, off, buf, writePos, len);
+        writePos += len;
+
+        // Set the new readLimit but only if there's enough data to allow
+        // encoding of at least one more byte.
+        if (writePos >= keepSizeAfter)
+            readLimit = writePos - keepSizeAfter;
+
+        processPendingBytes();
+
+        // Tell the caller how much input we actually copied into
+        // the dictionary.
+        return len;
+    }
+
+    /**
+     * Process pending bytes remaining from preset dictionary initialization
+     * or encoder flush operation.
+     */
+    private void processPendingBytes() {
+        // After flushing or setting a preset dictionary there will be
+        // pending data that hasn't been ran through the match finder yet.
+        // Run it through the match finder now if there is enough new data
+        // available (readPos < readLimit) that the encoder may encode at
+        // least one more input byte. This way we don't waste any time
+        // looping in the match finder (and marking the same bytes as
+        // pending again) if the application provides very little new data
+        // per write call.
+        if (pendingSize > 0 && readPos < readLimit) {
+            readPos -= pendingSize;
+            int oldPendingSize = pendingSize;
+            pendingSize = 0;
+            skip(oldPendingSize);
+            assert pendingSize < oldPendingSize;
+        }
+    }
+
+    /**
+     * Returns true if at least one byte has already been run through
+     * the match finder.
+     */
+    public boolean isStarted() {
+        return readPos != -1;
+    }
+
+    /**
+     * Marks that all the input needs to be made available in
+     * the encoded output.
+     */
+    public void setFlushing() {
+        readLimit = writePos - 1;
+        processPendingBytes();
+    }
+
+    /**
+     * Marks that there is no more input remaining. The read position
+     * can be advanced until the end of the data.
+     */
+    public void setFinishing() {
+        readLimit = writePos - 1;
+        finishing = true;
+        processPendingBytes();
+    }
+
+    /**
+     * Tests if there is enough input available to let the caller encode
+     * at least one more byte.
+     */
+    public boolean hasEnoughData(int alreadyReadLen) {
+        return readPos - alreadyReadLen < readLimit;
+    }
+
+    public void copyUncompressed(OutputStream out, int backward, int len)
+            throws IOException {
+        out.write(buf, readPos + 1 - backward, len);
+    }
+
+    /**
+     * Get the number of bytes available, including the current byte.
+     * <p>
+     * Note that the result is undefined if <code>getMatches</code> or
+     * <code>skip</code> hasn't been called yet and no preset dictionary
+     * is being used.
+     */
+    public int getAvail() {
+        assert isStarted();
+        return writePos - readPos;
+    }
+
+    /**
+     * Gets the lowest four bits of the absolute offset of the current byte.
+     * Bits other than the lowest four are undefined.
+     */
+    public int getPos() {
+        return readPos;
+    }
+
+    /**
+     * Gets the byte from the given backward offset.
+     * <p>
+     * The current byte is at <code>0</code>, the previous byte
+     * at <code>1</code> etc. To get a byte at zero-based distance,
+     * use <code>getByte(dist + 1)<code>.
+     * <p>
+     * This function is equivalent to <code>getByte(0, backward)</code>.
+     */
+    public int getByte(int backward) {
+        return buf[readPos - backward] & 0xFF;
+    }
+
+    /**
+     * Gets the byte from the given forward minus backward offset.
+     * The forward offset is added to the current position. This lets
+     * one read bytes ahead of the current byte.
+     */
+    public int getByte(int forward, int backward) {
+        return buf[readPos + forward - backward] & 0xFF;
+    }
+
+    /**
+     * Get the length of a match at the given distance.
+     *
+     * @param       dist        zero-based distance of the match to test
+     * @param       lenLimit    don't test for a match longer than this
+     *
+     * @return      length of the match; it is in the range [0, lenLimit]
+     */
+    public int getMatchLen(int dist, int lenLimit) {
+        int backPos = readPos - dist - 1;
+        int len = 0;
+
+        while (len < lenLimit && buf[readPos + len] == buf[backPos + len])
+            ++len;
+
+        return len;
+    }
+
+    /**
+     * Get the length of a match at the given distance and forward offset.
+     *
+     * @param       forward     forward offset
+     * @param       dist        zero-based distance of the match to test
+     * @param       lenLimit    don't test for a match longer than this
+     *
+     * @return      length of the match; it is in the range [0, lenLimit]
+     */
+    public int getMatchLen(int forward, int dist, int lenLimit) {
+        int curPos = readPos + forward;
+        int backPos = curPos - dist - 1;
+        int len = 0;
+
+        while (len < lenLimit && buf[curPos + len] == buf[backPos + len])
+            ++len;
+
+        return len;
+    }
+
+    /**
+     * Verifies that the matches returned by the match finder are valid.
+     * This is meant to be used in an assert statement. This is totally
+     * useless for actual encoding since match finder's results should
+     * naturally always be valid if it isn't broken.
+     *
+     * @param       matches     return value from <code>getMatches</code>
+     *
+     * @return      true if matches are valid, false if match finder is broken
+     */
+    public boolean verifyMatches(Matches matches) {
+        int lenLimit = Math.min(getAvail(), matchLenMax);
+
+        for (int i = 0; i < matches.count; ++i)
+            if (getMatchLen(matches.dist[i], lenLimit) != matches.len[i])
+                return false;
+
+        return true;
+    }
+
+    /**
+     * Moves to the next byte, checks if there is enough input available,
+     * and returns the amount of input available.
+     *
+     * @param       requiredForFlushing
+     *                          minimum number of available bytes when
+     *                          flushing; encoding may be continued with
+     *                          new input after flushing
+     * @param       requiredForFinishing
+     *                          minimum number of available bytes when
+     *                          finishing; encoding must not be continued
+     *                          after finishing or the match finder state
+     *                          may be corrupt
+     *
+     * @return      the number of bytes available or zero if there
+     *              is not enough input available
+     */
+    int movePos(int requiredForFlushing, int requiredForFinishing) {
+        assert requiredForFlushing >= requiredForFinishing;
+
+        ++readPos;
+        int avail = writePos - readPos;
+
+        if (avail < requiredForFlushing) {
+            if (avail < requiredForFinishing || !finishing) {
+                ++pendingSize;
+                avail = 0;
+            }
+        }
+
+        return avail;
+    }
+
+    /**
+     * Runs match finder for the next byte and returns the matches found.
+     */
+    public abstract Matches getMatches();
+
+    /**
+     * Skips the given number of bytes in the match finder.
+     */
+    public abstract void skip(int len);
+}

app/src/main/java/org/tukaani/xz/lz/Matches.java

@@ -0,0 +1,22 @@
+/*
+ * Matches
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lz;
+
+public final class Matches {
+    public final int[] len;
+    public final int[] dist;
+    public int count = 0;
+
+    Matches(int countMax) {
+        len = new int[countMax];
+        dist = new int[countMax];
+    }
+}

app/src/main/java/org/tukaani/xz/lzma/LZMACoder.java

@@ -0,0 +1,140 @@
+/*
+ * LZMACoder
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lzma;
+
+import org.tukaani.xz.rangecoder.RangeCoder;
+
+abstract class LZMACoder {
+    static final int POS_STATES_MAX = 1 << 4;
+
+    static final int MATCH_LEN_MIN = 2;
+    static final int MATCH_LEN_MAX = MATCH_LEN_MIN + LengthCoder.LOW_SYMBOLS
+                                     + LengthCoder.MID_SYMBOLS
+                                     + LengthCoder.HIGH_SYMBOLS - 1;
+
+    static final int DIST_STATES = 4;
+    static final int DIST_SLOTS = 1 << 6;
+    static final int DIST_MODEL_START = 4;
+    static final int DIST_MODEL_END = 14;
+    static final int FULL_DISTANCES = 1 << (DIST_MODEL_END / 2);
+
+    static final int ALIGN_BITS = 4;
+    static final int ALIGN_SIZE = 1 << ALIGN_BITS;
+    static final int ALIGN_MASK = ALIGN_SIZE - 1;
+
+    static final int REPS = 4;
+
+    final int posMask;
+
+    final int[] reps = new int[REPS];
+    final State state = new State();
+
+    final short[][] isMatch = new short[State.STATES][POS_STATES_MAX];
+    final short[] isRep = new short[State.STATES];
+    final short[] isRep0 = new short[State.STATES];
+    final short[] isRep1 = new short[State.STATES];
+    final short[] isRep2 = new short[State.STATES];
+    final short[][] isRep0Long = new short[State.STATES][POS_STATES_MAX];
+    final short[][] distSlots = new short[DIST_STATES][DIST_SLOTS];
+    final short[][] distSpecial = { new short[2], new short[2],
+                                    new short[4], new short[4],
+                                    new short[8], new short[8],
+                                    new short[16], new short[16],
+                                    new short[32], new short[32] };
+    final short[] distAlign = new short[ALIGN_SIZE];
+
+    static final int getDistState(int len) {
+        return len < DIST_STATES + MATCH_LEN_MIN
+               ? len - MATCH_LEN_MIN
+               : DIST_STATES - 1;
+    }
+
+    LZMACoder(int pb) {
+        posMask = (1 << pb) - 1;
+    }
+
+    void reset() {
+        reps[0] = 0;
+        reps[1] = 0;
+        reps[2] = 0;
+        reps[3] = 0;
+        state.reset();
+
+        for (int i = 0; i < isMatch.length; ++i)
+            RangeCoder.initProbs(isMatch[i]);
+
+        RangeCoder.initProbs(isRep);
+        RangeCoder.initProbs(isRep0);
+        RangeCoder.initProbs(isRep1);
+        RangeCoder.initProbs(isRep2);
+
+        for (int i = 0; i < isRep0Long.length; ++i)
+            RangeCoder.initProbs(isRep0Long[i]);
+
+        for (int i = 0; i < distSlots.length; ++i)
+            RangeCoder.initProbs(distSlots[i]);
+
+        for (int i = 0; i < distSpecial.length; ++i)
+            RangeCoder.initProbs(distSpecial[i]);
+
+        RangeCoder.initProbs(distAlign);
+    }
+
+
+    abstract class LiteralCoder {
+        private final int lc;
+        private final int literalPosMask;
+
+        LiteralCoder(int lc, int lp) {
+            this.lc = lc;
+            this.literalPosMask = (1 << lp) - 1;
+        }
+
+        final int getSubcoderIndex(int prevByte, int pos) {
+            int low = prevByte >> (8 - lc);
+            int high = (pos & literalPosMask) << lc;
+            return low + high;
+        }
+
+
+        abstract class LiteralSubcoder {
+            final short[] probs = new short[0x300];
+
+            void reset() {
+                RangeCoder.initProbs(probs);
+            }
+        }
+    }
+
+
+    abstract class LengthCoder {
+        static final int LOW_SYMBOLS = 1 << 3;
+        static final int MID_SYMBOLS = 1 << 3;
+        static final int HIGH_SYMBOLS = 1 << 8;
+
+        final short[] choice = new short[2];
+        final short[][] low = new short[POS_STATES_MAX][LOW_SYMBOLS];
+        final short[][] mid = new short[POS_STATES_MAX][MID_SYMBOLS];
+        final short[] high = new short[HIGH_SYMBOLS];
+
+        void reset() {
+            RangeCoder.initProbs(choice);
+
+            for (int i = 0; i < low.length; ++i)
+                RangeCoder.initProbs(low[i]);
+
+            for (int i = 0; i < low.length; ++i)
+                RangeCoder.initProbs(mid[i]);
+
+            RangeCoder.initProbs(high);
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/lzma/LZMADecoder.java

@@ -0,0 +1,199 @@
+/*
+ * LZMADecoder
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lzma;
+
+import java.io.IOException;
+import org.tukaani.xz.lz.LZDecoder;
+import org.tukaani.xz.rangecoder.RangeDecoder;
+
+public final class LZMADecoder extends LZMACoder {
+    private final LZDecoder lz;
+    private final RangeDecoder rc;
+    private final LiteralDecoder literalDecoder;
+    private final LengthDecoder matchLenDecoder = new LengthDecoder();
+    private final LengthDecoder repLenDecoder = new LengthDecoder();
+
+    public LZMADecoder(LZDecoder lz, RangeDecoder rc, int lc, int lp, int pb) {
+        super(pb);
+        this.lz = lz;
+        this.rc = rc;
+        this.literalDecoder = new LiteralDecoder(lc, lp);
+        reset();
+    }
+
+    public void reset() {
+        super.reset();
+        literalDecoder.reset();
+        matchLenDecoder.reset();
+        repLenDecoder.reset();
+    }
+
+    /**
+     * Returns true if LZMA end marker was detected. It is encoded as
+     * the maximum match distance which with signed ints becomes -1. This
+     * function is needed only for LZMA1. LZMA2 doesn't use the end marker
+     * in the LZMA layer.
+     */
+    public boolean endMarkerDetected() {
+        return reps[0] == -1;
+    }
+
+    public void decode() throws IOException {
+        lz.repeatPending();
+
+        while (lz.hasSpace()) {
+            int posState = lz.getPos() & posMask;
+
+            if (rc.decodeBit(isMatch[state.get()], posState) == 0) {
+                literalDecoder.decode();
+            } else {
+                int len = rc.decodeBit(isRep, state.get()) == 0
+                          ? decodeMatch(posState)
+                          : decodeRepMatch(posState);
+
+                // NOTE: With LZMA1 streams that have the end marker,
+                // this will throw CorruptedInputException. LZMAInputStream
+                // handles it specially.
+                lz.repeat(reps[0], len);
+            }
+        }
+
+        rc.normalize();
+    }
+
+    private int decodeMatch(int posState) throws IOException {
+        state.updateMatch();
+
+        reps[3] = reps[2];
+        reps[2] = reps[1];
+        reps[1] = reps[0];
+
+        int len = matchLenDecoder.decode(posState);
+        int distSlot = rc.decodeBitTree(distSlots[getDistState(len)]);
+
+        if (distSlot < DIST_MODEL_START) {
+            reps[0] = distSlot;
+        } else {
+            int limit = (distSlot >> 1) - 1;
+            reps[0] = (2 | (distSlot & 1)) << limit;
+
+            if (distSlot < DIST_MODEL_END) {
+                reps[0] |= rc.decodeReverseBitTree(
+                        distSpecial[distSlot - DIST_MODEL_START]);
+            } else {
+                reps[0] |= rc.decodeDirectBits(limit - ALIGN_BITS)
+                           << ALIGN_BITS;
+                reps[0] |= rc.decodeReverseBitTree(distAlign);
+            }
+        }
+
+        return len;
+    }
+
+    private int decodeRepMatch(int posState) throws IOException {
+        if (rc.decodeBit(isRep0, state.get()) == 0) {
+            if (rc.decodeBit(isRep0Long[state.get()], posState) == 0) {
+                state.updateShortRep();
+                return 1;
+            }
+        } else {
+            int tmp;
+
+            if (rc.decodeBit(isRep1, state.get()) == 0) {
+                tmp = reps[1];
+            } else {
+                if (rc.decodeBit(isRep2, state.get()) == 0) {
+                    tmp = reps[2];
+                } else {
+                    tmp = reps[3];
+                    reps[3] = reps[2];
+                }
+
+                reps[2] = reps[1];
+            }
+
+            reps[1] = reps[0];
+            reps[0] = tmp;
+        }
+
+        state.updateLongRep();
+
+        return repLenDecoder.decode(posState);
+    }
+
+
+    private class LiteralDecoder extends LiteralCoder {
+        private final LiteralSubdecoder[] subdecoders;
+
+        LiteralDecoder(int lc, int lp) {
+            super(lc, lp);
+
+            subdecoders = new LiteralSubdecoder[1 << (lc + lp)];
+            for (int i = 0; i < subdecoders.length; ++i)
+                subdecoders[i] = new LiteralSubdecoder();
+        }
+
+        void reset() {
+            for (int i = 0; i < subdecoders.length; ++i)
+                subdecoders[i].reset();
+        }
+
+        void decode() throws IOException {
+            int i = getSubcoderIndex(lz.getByte(0), lz.getPos());
+            subdecoders[i].decode();
+        }
+
+
+        private class LiteralSubdecoder extends LiteralSubcoder {
+            void decode() throws IOException {
+                int symbol = 1;
+
+                if (state.isLiteral()) {
+                    do {
+                        symbol = (symbol << 1) | rc.decodeBit(probs, symbol);
+                    } while (symbol < 0x100);
+
+                } else {
+                    int matchByte = lz.getByte(reps[0]);
+                    int offset = 0x100;
+                    int matchBit;
+                    int bit;
+
+                    do {
+                        matchByte <<= 1;
+                        matchBit = matchByte & offset;
+                        bit = rc.decodeBit(probs, offset + matchBit + symbol);
+                        symbol = (symbol << 1) | bit;
+                        offset &= (0 - bit) ^ ~matchBit;
+                    } while (symbol < 0x100);
+                }
+
+                lz.putByte((byte)symbol);
+                state.updateLiteral();
+            }
+        }
+    }
+
+
+    private class LengthDecoder extends LengthCoder {
+        int decode(int posState) throws IOException {
+            if (rc.decodeBit(choice, 0) == 0)
+                return rc.decodeBitTree(low[posState]) + MATCH_LEN_MIN;
+
+            if (rc.decodeBit(choice, 1) == 0)
+                return rc.decodeBitTree(mid[posState])
+                       + MATCH_LEN_MIN + LOW_SYMBOLS;
+
+            return rc.decodeBitTree(high)
+                   + MATCH_LEN_MIN + LOW_SYMBOLS + MID_SYMBOLS;
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/lzma/LZMAEncoder.java

@@ -0,0 +1,750 @@
+/*
+ * LZMAEncoder
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lzma;
+
+import java.io.IOException;
+import org.tukaani.xz.ArrayCache;
+import org.tukaani.xz.lz.LZEncoder;
+import org.tukaani.xz.lz.Matches;
+import org.tukaani.xz.rangecoder.RangeEncoder;
+
+public abstract class LZMAEncoder extends LZMACoder {
+    public static final int MODE_FAST = 1;
+    public static final int MODE_NORMAL = 2;
+
+    /**
+     * LZMA2 chunk is considered full when its uncompressed size exceeds
+     * <code>LZMA2_UNCOMPRESSED_LIMIT</code>.
+     * <p>
+     * A compressed LZMA2 chunk can hold 2 MiB of uncompressed data.
+     * A single LZMA symbol may indicate up to MATCH_LEN_MAX bytes
+     * of data, so the LZMA2 chunk is considered full when there is
+     * less space than MATCH_LEN_MAX bytes.
+     */
+    private static final int LZMA2_UNCOMPRESSED_LIMIT
+            = (2 << 20) - MATCH_LEN_MAX;
+
+    /**
+     * LZMA2 chunk is considered full when its compressed size exceeds
+     * <code>LZMA2_COMPRESSED_LIMIT</code>.
+     * <p>
+     * The maximum compressed size of a LZMA2 chunk is 64 KiB.
+     * A single LZMA symbol might use 20 bytes of space even though
+     * it usually takes just one byte or so. Two more bytes are needed
+     * for LZMA2 uncompressed chunks (see LZMA2OutputStream.writeChunk).
+     * Leave a little safety margin and use 26 bytes.
+     */
+    private static final int LZMA2_COMPRESSED_LIMIT = (64 << 10) - 26;
+
+    private static final int DIST_PRICE_UPDATE_INTERVAL = FULL_DISTANCES;
+    private static final int ALIGN_PRICE_UPDATE_INTERVAL = ALIGN_SIZE;
+
+    private final RangeEncoder rc;
+    final LZEncoder lz;
+    final LiteralEncoder literalEncoder;
+    final LengthEncoder matchLenEncoder;
+    final LengthEncoder repLenEncoder;
+    final int niceLen;
+
+    private int distPriceCount = 0;
+    private int alignPriceCount = 0;
+
+    private final int distSlotPricesSize;
+    private final int[][] distSlotPrices;
+    private final int[][] fullDistPrices
+            = new int[DIST_STATES][FULL_DISTANCES];
+    private final int[] alignPrices = new int[ALIGN_SIZE];
+
+    int back = 0;
+    int readAhead = -1;
+    private int uncompressedSize = 0;
+
+    public static int getMemoryUsage(int mode, int dictSize,
+                                     int extraSizeBefore, int mf) {
+        int m = 80;
+
+        switch (mode) {
+            case MODE_FAST:
+                m += LZMAEncoderFast.getMemoryUsage(
+                        dictSize, extraSizeBefore, mf);
+                break;
+
+            case MODE_NORMAL:
+                m += LZMAEncoderNormal.getMemoryUsage(
+                        dictSize, extraSizeBefore, mf);
+                break;
+
+            default:
+                throw new IllegalArgumentException();
+        }
+
+        return m;
+    }
+
+    public static LZMAEncoder getInstance(
+                RangeEncoder rc, int lc, int lp, int pb, int mode,
+                int dictSize, int extraSizeBefore,
+                int niceLen, int mf, int depthLimit,
+                ArrayCache arrayCache) {
+        switch (mode) {
+            case MODE_FAST:
+                return new LZMAEncoderFast(rc, lc, lp, pb,
+                                           dictSize, extraSizeBefore,
+                                           niceLen, mf, depthLimit,
+                                           arrayCache);
+
+            case MODE_NORMAL:
+                return new LZMAEncoderNormal(rc, lc, lp, pb,
+                                             dictSize, extraSizeBefore,
+                                             niceLen, mf, depthLimit,
+                                             arrayCache);
+        }
+
+        throw new IllegalArgumentException();
+    }
+
+    public void putArraysToCache(ArrayCache arrayCache) {
+        lz.putArraysToCache(arrayCache);
+    }
+
+    /**
+     * Gets an integer [0, 63] matching the highest two bits of an integer.
+     * This is like bit scan reverse (BSR) on x86 except that this also
+     * cares about the second highest bit.
+     */
+    public static int getDistSlot(int dist) {
+        if (dist <= DIST_MODEL_START && dist >= 0)
+            return dist;
+
+        int n = dist;
+        int i = 31;
+
+        if ((n & 0xFFFF0000) == 0) {
+            n <<= 16;
+            i = 15;
+        }
+
+        if ((n & 0xFF000000) == 0) {
+            n <<= 8;
+            i -= 8;
+        }
+
+        if ((n & 0xF0000000) == 0) {
+            n <<= 4;
+            i -= 4;
+        }
+
+        if ((n & 0xC0000000) == 0) {
+            n <<= 2;
+            i -= 2;
+        }
+
+        if ((n & 0x80000000) == 0)
+            --i;
+
+        return (i << 1) + ((dist >>> (i - 1)) & 1);
+    }
+
+    /**
+     * Gets the next LZMA symbol.
+     * <p>
+     * There are three types of symbols: literal (a single byte),
+     * repeated match, and normal match. The symbol is indicated
+     * by the return value and by the variable <code>back</code>.
+     * <p>
+     * Literal: <code>back == -1</code> and return value is <code>1</code>.
+     * The literal itself needs to be read from <code>lz</code> separately.
+     * <p>
+     * Repeated match: <code>back</code> is in the range [0, 3] and
+     * the return value is the length of the repeated match.
+     * <p>
+     * Normal match: <code>back - REPS<code> (<code>back - 4</code>)
+     * is the distance of the match and the return value is the length
+     * of the match.
+     */
+    abstract int getNextSymbol();
+
+    LZMAEncoder(RangeEncoder rc, LZEncoder lz,
+                int lc, int lp, int pb, int dictSize, int niceLen) {
+        super(pb);
+        this.rc = rc;
+        this.lz = lz;
+        this.niceLen = niceLen;
+
+        literalEncoder = new LiteralEncoder(lc, lp);
+        matchLenEncoder = new LengthEncoder(pb, niceLen);
+        repLenEncoder = new LengthEncoder(pb, niceLen);
+
+        distSlotPricesSize = getDistSlot(dictSize - 1) + 1;
+        distSlotPrices = new int[DIST_STATES][distSlotPricesSize];
+
+        reset();
+    }
+
+    public LZEncoder getLZEncoder() {
+        return lz;
+    }
+
+    public void reset() {
+        super.reset();
+        literalEncoder.reset();
+        matchLenEncoder.reset();
+        repLenEncoder.reset();
+        distPriceCount = 0;
+        alignPriceCount = 0;
+
+        uncompressedSize += readAhead + 1;
+        readAhead = -1;
+    }
+
+    public int getUncompressedSize() {
+        return uncompressedSize;
+    }
+
+    public void resetUncompressedSize() {
+        uncompressedSize = 0;
+    }
+
+    /**
+     * Compress for LZMA1.
+     */
+    public void encodeForLZMA1() throws IOException {
+        if (!lz.isStarted() && !encodeInit())
+            return;
+
+        while (encodeSymbol()) {}
+    }
+
+    public void encodeLZMA1EndMarker() throws IOException {
+        // End of stream marker is encoded as a match with the maximum
+        // possible distance. The length is ignored by the decoder,
+        // but the minimum length has been used by the LZMA SDK.
+        //
+        // Distance is a 32-bit unsigned integer in LZMA.
+        // With Java's signed int, UINT32_MAX becomes -1.
+        int posState = (lz.getPos() - readAhead) & posMask;
+        rc.encodeBit(isMatch[state.get()], posState, 1);
+        rc.encodeBit(isRep, state.get(), 0);
+        encodeMatch(-1, MATCH_LEN_MIN, posState);
+    }
+
+    /**
+     * Compresses for LZMA2.
+     *
+     * @return      true if the LZMA2 chunk became full, false otherwise
+     */
+    public boolean encodeForLZMA2() {
+        // LZMA2 uses RangeEncoderToBuffer so IOExceptions aren't possible.
+        try {
+            if (!lz.isStarted() && !encodeInit())
+                return false;
+
+            while (uncompressedSize <= LZMA2_UNCOMPRESSED_LIMIT
+                    && rc.getPendingSize() <= LZMA2_COMPRESSED_LIMIT)
+                if (!encodeSymbol())
+                    return false;
+        } catch (IOException e) {
+            throw new Error();
+        }
+
+        return true;
+    }
+
+    private boolean encodeInit() throws IOException {
+        assert readAhead == -1;
+        if (!lz.hasEnoughData(0))
+            return false;
+
+        // The first symbol must be a literal unless using
+        // a preset dictionary. This code isn't run if using
+        // a preset dictionary.
+        skip(1);
+        rc.encodeBit(isMatch[state.get()], 0, 0);
+        literalEncoder.encodeInit();
+
+        --readAhead;
+        assert readAhead == -1;
+
+        ++uncompressedSize;
+        assert uncompressedSize == 1;
+
+        return true;
+    }
+
+    private boolean encodeSymbol() throws IOException {
+        if (!lz.hasEnoughData(readAhead + 1))
+            return false;
+
+        int len = getNextSymbol();
+
+        assert readAhead >= 0;
+        int posState = (lz.getPos() - readAhead) & posMask;
+
+        if (back == -1) {
+            // Literal i.e. eight-bit byte
+            assert len == 1;
+            rc.encodeBit(isMatch[state.get()], posState, 0);
+            literalEncoder.encode();
+        } else {
+            // Some type of match
+            rc.encodeBit(isMatch[state.get()], posState, 1);
+            if (back < REPS) {
+                // Repeated match i.e. the same distance
+                // has been used earlier.
+                assert lz.getMatchLen(-readAhead, reps[back], len) == len;
+                rc.encodeBit(isRep, state.get(), 1);
+                encodeRepMatch(back, len, posState);
+            } else {
+                // Normal match
+                assert lz.getMatchLen(-readAhead, back - REPS, len) == len;
+                rc.encodeBit(isRep, state.get(), 0);
+                encodeMatch(back - REPS, len, posState);
+            }
+        }
+
+        readAhead -= len;
+        uncompressedSize += len;
+
+        return true;
+    }
+
+    private void encodeMatch(int dist, int len, int posState)
+            throws IOException {
+        state.updateMatch();
+        matchLenEncoder.encode(len, posState);
+
+        int distSlot = getDistSlot(dist);
+        rc.encodeBitTree(distSlots[getDistState(len)], distSlot);
+
+        if (distSlot >= DIST_MODEL_START) {
+            int footerBits = (distSlot >>> 1) - 1;
+            int base = (2 | (distSlot & 1)) << footerBits;
+            int distReduced = dist - base;
+
+            if (distSlot < DIST_MODEL_END) {
+                rc.encodeReverseBitTree(
+                        distSpecial[distSlot - DIST_MODEL_START],
+                        distReduced);
+            } else {
+                rc.encodeDirectBits(distReduced >>> ALIGN_BITS,
+                                    footerBits - ALIGN_BITS);
+                rc.encodeReverseBitTree(distAlign, distReduced & ALIGN_MASK);
+                --alignPriceCount;
+            }
+        }
+
+        reps[3] = reps[2];
+        reps[2] = reps[1];
+        reps[1] = reps[0];
+        reps[0] = dist;
+
+        --distPriceCount;
+    }
+
+    private void encodeRepMatch(int rep, int len, int posState)
+            throws IOException {
+        if (rep == 0) {
+            rc.encodeBit(isRep0, state.get(), 0);
+            rc.encodeBit(isRep0Long[state.get()], posState, len == 1 ? 0 : 1);
+        } else {
+            int dist = reps[rep];
+            rc.encodeBit(isRep0, state.get(), 1);
+
+            if (rep == 1) {
+                rc.encodeBit(isRep1, state.get(), 0);
+            } else {
+                rc.encodeBit(isRep1, state.get(), 1);
+                rc.encodeBit(isRep2, state.get(), rep - 2);
+
+                if (rep == 3)
+                    reps[3] = reps[2];
+
+                reps[2] = reps[1];
+            }
+
+            reps[1] = reps[0];
+            reps[0] = dist;
+        }
+
+        if (len == 1) {
+            state.updateShortRep();
+        } else {
+            repLenEncoder.encode(len, posState);
+            state.updateLongRep();
+        }
+    }
+
+    Matches getMatches() {
+        ++readAhead;
+        Matches matches = lz.getMatches();
+        assert lz.verifyMatches(matches);
+        return matches;
+    }
+
+    void skip(int len) {
+        readAhead += len;
+        lz.skip(len);
+    }
+
+    int getAnyMatchPrice(State state, int posState) {
+        return RangeEncoder.getBitPrice(isMatch[state.get()][posState], 1);
+    }
+
+    int getNormalMatchPrice(int anyMatchPrice, State state) {
+        return anyMatchPrice
+               + RangeEncoder.getBitPrice(isRep[state.get()], 0);
+    }
+
+    int getAnyRepPrice(int anyMatchPrice, State state) {
+        return anyMatchPrice
+               + RangeEncoder.getBitPrice(isRep[state.get()], 1);
+    }
+
+    int getShortRepPrice(int anyRepPrice, State state, int posState) {
+        return anyRepPrice
+               + RangeEncoder.getBitPrice(isRep0[state.get()], 0)
+               + RangeEncoder.getBitPrice(isRep0Long[state.get()][posState],
+                                          0);
+    }
+
+    int getLongRepPrice(int anyRepPrice, int rep, State state, int posState) {
+        int price = anyRepPrice;
+
+        if (rep == 0) {
+            price += RangeEncoder.getBitPrice(isRep0[state.get()], 0)
+                     + RangeEncoder.getBitPrice(
+                       isRep0Long[state.get()][posState], 1);
+        } else {
+            price += RangeEncoder.getBitPrice(isRep0[state.get()], 1);
+
+            if (rep == 1)
+                price += RangeEncoder.getBitPrice(isRep1[state.get()], 0);
+            else
+                price += RangeEncoder.getBitPrice(isRep1[state.get()], 1)
+                         + RangeEncoder.getBitPrice(isRep2[state.get()],
+                                                    rep - 2);
+        }
+
+        return price;
+    }
+
+    int getLongRepAndLenPrice(int rep, int len, State state, int posState) {
+        int anyMatchPrice = getAnyMatchPrice(state, posState);
+        int anyRepPrice = getAnyRepPrice(anyMatchPrice, state);
+        int longRepPrice = getLongRepPrice(anyRepPrice, rep, state, posState);
+        return longRepPrice + repLenEncoder.getPrice(len, posState);
+    }
+
+    int getMatchAndLenPrice(int normalMatchPrice,
+                            int dist, int len, int posState) {
+        int price = normalMatchPrice
+                    + matchLenEncoder.getPrice(len, posState);
+        int distState = getDistState(len);
+
+        if (dist < FULL_DISTANCES) {
+            price += fullDistPrices[distState][dist];
+        } else {
+            // Note that distSlotPrices includes also
+            // the price of direct bits.
+            int distSlot = getDistSlot(dist);
+            price += distSlotPrices[distState][distSlot]
+                     + alignPrices[dist & ALIGN_MASK];
+        }
+
+        return price;
+    }
+
+    private void updateDistPrices() {
+        distPriceCount = DIST_PRICE_UPDATE_INTERVAL;
+
+        for (int distState = 0; distState < DIST_STATES; ++distState) {
+            for (int distSlot = 0; distSlot < distSlotPricesSize; ++distSlot)
+                distSlotPrices[distState][distSlot]
+                        = RangeEncoder.getBitTreePrice(
+                          distSlots[distState], distSlot);
+
+            for (int distSlot = DIST_MODEL_END; distSlot < distSlotPricesSize;
+                    ++distSlot) {
+                int count = (distSlot >>> 1) - 1 - ALIGN_BITS;
+                distSlotPrices[distState][distSlot]
+                        += RangeEncoder.getDirectBitsPrice(count);
+            }
+
+            for (int dist = 0; dist < DIST_MODEL_START; ++dist)
+                fullDistPrices[distState][dist]
+                        = distSlotPrices[distState][dist];
+        }
+
+        int dist = DIST_MODEL_START;
+        for (int distSlot = DIST_MODEL_START; distSlot < DIST_MODEL_END;
+                ++distSlot) {
+            int footerBits = (distSlot >>> 1) - 1;
+            int base = (2 | (distSlot & 1)) << footerBits;
+
+            int limit = distSpecial[distSlot - DIST_MODEL_START].length;
+            for (int i = 0; i < limit; ++i) {
+                int distReduced = dist - base;
+                int price = RangeEncoder.getReverseBitTreePrice(
+                        distSpecial[distSlot - DIST_MODEL_START],
+                        distReduced);
+
+                for (int distState = 0; distState < DIST_STATES; ++distState)
+                    fullDistPrices[distState][dist]
+                            = distSlotPrices[distState][distSlot] + price;
+
+                ++dist;
+            }
+        }
+
+        assert dist == FULL_DISTANCES;
+    }
+
+    private void updateAlignPrices() {
+        alignPriceCount = ALIGN_PRICE_UPDATE_INTERVAL;
+
+        for (int i = 0; i < ALIGN_SIZE; ++i)
+            alignPrices[i] = RangeEncoder.getReverseBitTreePrice(distAlign,
+                                                                 i);
+    }
+
+    /**
+     * Updates the lookup tables used for calculating match distance
+     * and length prices. The updating is skipped for performance reasons
+     * if the tables haven't changed much since the previous update.
+     */
+    void updatePrices() {
+        if (distPriceCount <= 0)
+            updateDistPrices();
+
+        if (alignPriceCount <= 0)
+            updateAlignPrices();
+
+        matchLenEncoder.updatePrices();
+        repLenEncoder.updatePrices();
+    }
+
+
+    class LiteralEncoder extends LiteralCoder {
+        private final LiteralSubencoder[] subencoders;
+
+        LiteralEncoder(int lc, int lp) {
+            super(lc, lp);
+
+            subencoders = new LiteralSubencoder[1 << (lc + lp)];
+            for (int i = 0; i < subencoders.length; ++i)
+                subencoders[i] = new LiteralSubencoder();
+        }
+
+        void reset() {
+            for (int i = 0; i < subencoders.length; ++i)
+                subencoders[i].reset();
+        }
+
+        void encodeInit() throws IOException {
+            // When encoding the first byte of the stream, there is
+            // no previous byte in the dictionary so the encode function
+            // wouldn't work.
+            assert readAhead >= 0;
+            subencoders[0].encode();
+        }
+
+        void encode() throws IOException {
+            assert readAhead >= 0;
+            int i = getSubcoderIndex(lz.getByte(1 + readAhead),
+                                     lz.getPos() - readAhead);
+            subencoders[i].encode();
+        }
+
+        int getPrice(int curByte, int matchByte,
+                     int prevByte, int pos, State state) {
+            int price = RangeEncoder.getBitPrice(
+                    isMatch[state.get()][pos & posMask], 0);
+
+            int i = getSubcoderIndex(prevByte, pos);
+            price += state.isLiteral()
+                   ? subencoders[i].getNormalPrice(curByte)
+                   : subencoders[i].getMatchedPrice(curByte, matchByte);
+
+            return price;
+        }
+
+        private class LiteralSubencoder extends LiteralSubcoder {
+            void encode() throws IOException {
+                int symbol = lz.getByte(readAhead) | 0x100;
+
+                if (state.isLiteral()) {
+                    int subencoderIndex;
+                    int bit;
+
+                    do {
+                        subencoderIndex = symbol >>> 8;
+                        bit = (symbol >>> 7) & 1;
+                        rc.encodeBit(probs, subencoderIndex, bit);
+                        symbol <<= 1;
+                    } while (symbol < 0x10000);
+
+                } else {
+                    int matchByte = lz.getByte(reps[0] + 1 + readAhead);
+                    int offset = 0x100;
+                    int subencoderIndex;
+                    int matchBit;
+                    int bit;
+
+                    do {
+                        matchByte <<= 1;
+                        matchBit = matchByte & offset;
+                        subencoderIndex = offset + matchBit + (symbol >>> 8);
+                        bit = (symbol >>> 7) & 1;
+                        rc.encodeBit(probs, subencoderIndex, bit);
+                        symbol <<= 1;
+                        offset &= ~(matchByte ^ symbol);
+                    } while (symbol < 0x10000);
+                }
+
+                state.updateLiteral();
+            }
+
+            int getNormalPrice(int symbol) {
+                int price = 0;
+                int subencoderIndex;
+                int bit;
+
+                symbol |= 0x100;
+
+                do {
+                    subencoderIndex = symbol >>> 8;
+                    bit = (symbol >>> 7) & 1;
+                    price += RangeEncoder.getBitPrice(probs[subencoderIndex],
+                                                      bit);
+                    symbol <<= 1;
+                } while (symbol < (0x100 << 8));
+
+                return price;
+            }
+
+            int getMatchedPrice(int symbol, int matchByte) {
+                int price = 0;
+                int offset = 0x100;
+                int subencoderIndex;
+                int matchBit;
+                int bit;
+
+                symbol |= 0x100;
+
+                do {
+                    matchByte <<= 1;
+                    matchBit = matchByte & offset;
+                    subencoderIndex = offset + matchBit + (symbol >>> 8);
+                    bit = (symbol >>> 7) & 1;
+                    price += RangeEncoder.getBitPrice(probs[subencoderIndex],
+                                                      bit);
+                    symbol <<= 1;
+                    offset &= ~(matchByte ^ symbol);
+                } while (symbol < (0x100 << 8));
+
+                return price;
+            }
+        }
+    }
+
+
+    class LengthEncoder extends LengthCoder {
+        /**
+         * The prices are updated after at least
+         * <code>PRICE_UPDATE_INTERVAL</code> many lengths
+         * have been encoded with the same posState.
+         */
+        private static final int PRICE_UPDATE_INTERVAL = 32; // FIXME?
+
+        private final int[] counters;
+        private final int[][] prices;
+
+        LengthEncoder(int pb, int niceLen) {
+            int posStates = 1 << pb;
+            counters = new int[posStates];
+
+            // Always allocate at least LOW_SYMBOLS + MID_SYMBOLS because
+            // it makes updatePrices slightly simpler. The prices aren't
+            // usually needed anyway if niceLen < 18.
+            int lenSymbols = Math.max(niceLen - MATCH_LEN_MIN + 1,
+                                      LOW_SYMBOLS + MID_SYMBOLS);
+            prices = new int[posStates][lenSymbols];
+        }
+
+        void reset() {
+            super.reset();
+
+            // Reset counters to zero to force price update before
+            // the prices are needed.
+            for (int i = 0; i < counters.length; ++i)
+                counters[i] = 0;
+        }
+
+        void encode(int len, int posState) throws IOException {
+            len -= MATCH_LEN_MIN;
+
+            if (len < LOW_SYMBOLS) {
+                rc.encodeBit(choice, 0, 0);
+                rc.encodeBitTree(low[posState], len);
+            } else {
+                rc.encodeBit(choice, 0, 1);
+                len -= LOW_SYMBOLS;
+
+                if (len < MID_SYMBOLS) {
+                    rc.encodeBit(choice, 1, 0);
+                    rc.encodeBitTree(mid[posState], len);
+                } else {
+                    rc.encodeBit(choice, 1, 1);
+                    rc.encodeBitTree(high, len - MID_SYMBOLS);
+                }
+            }
+
+            --counters[posState];
+        }
+
+        int getPrice(int len, int posState) {
+            return prices[posState][len - MATCH_LEN_MIN];
+        }
+
+        void updatePrices() {
+            for (int posState = 0; posState < counters.length; ++posState) {
+                if (counters[posState] <= 0) {
+                    counters[posState] = PRICE_UPDATE_INTERVAL;
+                    updatePrices(posState);
+                }
+            }
+        }
+
+        private void updatePrices(int posState) {
+            int choice0Price = RangeEncoder.getBitPrice(choice[0], 0);
+
+            int i = 0;
+            for (; i < LOW_SYMBOLS; ++i)
+                prices[posState][i] = choice0Price
+                        + RangeEncoder.getBitTreePrice(low[posState], i);
+
+            choice0Price = RangeEncoder.getBitPrice(choice[0], 1);
+            int choice1Price = RangeEncoder.getBitPrice(choice[1], 0);
+
+            for (; i < LOW_SYMBOLS + MID_SYMBOLS; ++i)
+                prices[posState][i] = choice0Price + choice1Price
+                         + RangeEncoder.getBitTreePrice(mid[posState],
+                                                        i - LOW_SYMBOLS);
+
+            choice1Price = RangeEncoder.getBitPrice(choice[1], 1);
+
+            for (; i < prices[posState].length; ++i)
+                prices[posState][i] = choice0Price + choice1Price
+                         + RangeEncoder.getBitTreePrice(high, i - LOW_SYMBOLS
+                                                              - MID_SYMBOLS);
+        }
+    }
+}

app/src/main/java/org/tukaani/xz/lzma/LZMAEncoderFast.java

@@ -0,0 +1,153 @@
+/*
+ * LZMAEncoderFast
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lzma;
+
+import org.tukaani.xz.ArrayCache;
+import org.tukaani.xz.lz.LZEncoder;
+import org.tukaani.xz.lz.Matches;
+import org.tukaani.xz.rangecoder.RangeEncoder;
+
+final class LZMAEncoderFast extends LZMAEncoder {
+    private static final int EXTRA_SIZE_BEFORE = 1;
+    private static final int EXTRA_SIZE_AFTER = MATCH_LEN_MAX - 1;
+
+    private Matches matches = null;
+
+    static int getMemoryUsage(int dictSize, int extraSizeBefore, int mf) {
+        return LZEncoder.getMemoryUsage(
+                dictSize, Math.max(extraSizeBefore, EXTRA_SIZE_BEFORE),
+                EXTRA_SIZE_AFTER, MATCH_LEN_MAX, mf);
+    }
+
+    LZMAEncoderFast(RangeEncoder rc, int lc, int lp, int pb,
+                           int dictSize, int extraSizeBefore,
+                           int niceLen, int mf, int depthLimit,
+                           ArrayCache arrayCache) {
+        super(rc, LZEncoder.getInstance(dictSize,
+                                        Math.max(extraSizeBefore,
+                                                 EXTRA_SIZE_BEFORE),
+                                        EXTRA_SIZE_AFTER,
+                                        niceLen, MATCH_LEN_MAX,
+                                        mf, depthLimit, arrayCache),
+              lc, lp, pb, dictSize, niceLen);
+    }
+
+    private boolean changePair(int smallDist, int bigDist) {
+        return smallDist < (bigDist >>> 7);
+    }
+
+    int getNextSymbol() {
+        // Get the matches for the next byte unless readAhead indicates
+        // that we already got the new matches during the previous call
+        // to this function.
+        if (readAhead == -1)
+            matches = getMatches();
+
+        back = -1;
+
+        // Get the number of bytes available in the dictionary, but
+        // not more than the maximum match length. If there aren't
+        // enough bytes remaining to encode a match at all, return
+        // immediately to encode this byte as a literal.
+        int avail = Math.min(lz.getAvail(), MATCH_LEN_MAX);
+        if (avail < MATCH_LEN_MIN)
+            return 1;
+
+        // Look for a match from the previous four match distances.
+        int bestRepLen = 0;
+        int bestRepIndex = 0;
+        for (int rep = 0; rep < REPS; ++rep) {
+            int len = lz.getMatchLen(reps[rep], avail);
+            if (len < MATCH_LEN_MIN)
+                continue;
+
+            // If it is long enough, return it.
+            if (len >= niceLen) {
+                back = rep;
+                skip(len - 1);
+                return len;
+            }
+
+            // Remember the index and length of the best repeated match.
+            if (len > bestRepLen) {
+                bestRepIndex = rep;
+                bestRepLen = len;
+            }
+        }
+
+        int mainLen = 0;
+        int mainDist = 0;
+
+        if (matches.count > 0) {
+            mainLen = matches.len[matches.count - 1];
+            mainDist = matches.dist[matches.count - 1];
+
+            if (mainLen >= niceLen) {
+                back = mainDist + REPS;
+                skip(mainLen - 1);
+                return mainLen;
+            }
+
+            while (matches.count > 1
+                    && mainLen == matches.len[matches.count - 2] + 1) {
+                if (!changePair(matches.dist[matches.count - 2], mainDist))
+                    break;
+
+                --matches.count;
+                mainLen = matches.len[matches.count - 1];
+                mainDist = matches.dist[matches.count - 1];
+            }
+
+            if (mainLen == MATCH_LEN_MIN && mainDist >= 0x80)
+                mainLen = 1;
+        }
+
+        if (bestRepLen >= MATCH_LEN_MIN) {
+            if (bestRepLen + 1 >= mainLen
+                    || (bestRepLen + 2 >= mainLen && mainDist >= (1 << 9))
+                    || (bestRepLen + 3 >= mainLen && mainDist >= (1 << 15))) {
+                back = bestRepIndex;
+                skip(bestRepLen - 1);
+                return bestRepLen;
+            }
+        }
+
+        if (mainLen < MATCH_LEN_MIN || avail <= MATCH_LEN_MIN)
+            return 1;
+
+        // Get the next match. Test if it is better than the current match.
+        // If so, encode the current byte as a literal.
+        matches = getMatches();
+
+        if (matches.count > 0) {
+            int newLen = matches.len[matches.count - 1];
+            int newDist = matches.dist[matches.count - 1];
+
+            if ((newLen >= mainLen && newDist < mainDist)
+                    || (newLen == mainLen + 1
+                        && !changePair(mainDist, newDist))
+                    || newLen > mainLen + 1
+                    || (newLen + 1 >= mainLen
+                        && mainLen >= MATCH_LEN_MIN + 1
+                        && changePair(newDist, mainDist)))
+                return 1;
+        }
+
+        int limit = Math.max(mainLen - 1, MATCH_LEN_MIN);
+        for (int rep = 0; rep < REPS; ++rep)
+            if (lz.getMatchLen(reps[rep], limit) == limit)
+                return 1;
+
+        back = mainDist + REPS;
+        skip(mainLen - 2);
+        return mainLen;
+    }
+}

app/src/main/java/org/tukaani/xz/lzma/LZMAEncoderNormal.java

@@ -0,0 +1,568 @@
+/*
+ * LZMAEncoderNormal
+ *
+ * Authors: Lasse Collin <lasse.collin@tukaani.org>
+ *          Igor Pavlov <http://7-zip.org/>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz.lzma;
+
+import org.tukaani.xz.ArrayCache;
+import org.tukaani.xz.lz.LZEncoder;
+import org.tukaani.xz.lz.Matches;
+import org.tukaani.xz.rangecoder.RangeEncoder;
+
+final class LZMAEncoderNormal extends LZMAEncoder {
+    private static final int OPTS = 4096;
+
+    private static final int EXTRA_SIZE_BEFORE = OPTS;
+    private static final int EXTRA_SIZE_AFTER = OPTS;
+
+    private final Optimum[] opts = new Optimum[OPTS];
+    private int optCur = 0;
+    private int optEnd = 0;
+
+    private Matches matches;
+
+    // These are fields solely to avoid allocating the objects again and
+    // again on each function call.
+    private final int[] repLens = new int[REPS];
+    private final State nextState = new State();
+
+    static int getMemoryUsage(int dictSize, int extraSizeBefore, int mf) {
+        return LZEncoder.getMemoryUsage(dictSize,
+                   Math.max(extraSizeBefore, EXTRA_SIZE_BEFORE),
+                   EXTRA_SIZE_AFTER, MATCH_LEN_MAX, mf)
+               + OPTS * 64 / 1024;
+    }
+
+    LZMAEncoderNormal(RangeEncoder rc, int lc, int lp, int pb,
+                             int dictSize, int extraSizeBefore,
+                             int niceLen, int mf, int depthLimit,
+                             ArrayCache arrayCache) {
+        super(rc, LZEncoder.getInstance(dictSize,
+                                        Math.max(extraSizeBefore,
+                                                 EXTRA_SIZE_BEFORE),
+                                        EXTRA_SIZE_AFTER,
+                                        niceLen, MATCH_LEN_MAX,
+                                        mf, depthLimit, arrayCache),
+              lc, lp, pb, dictSize, niceLen);
+
+        for (int i = 0; i < OPTS; ++i)
+            opts[i] = new Optimum();
+    }
+
+    public void reset() {
+        optCur = 0;
+        optEnd = 0;
+        super.reset();
+    }
+
+    /**
+     * Converts the opts array from backward indexes to forward indexes.
+     * Then it will be simple to get the next symbol from the array
+     * in later calls to <code>getNextSymbol()</code>.
+     */
+    private int convertOpts() {
+        optEnd = optCur;
+
+        int optPrev = opts[optCur].optPrev;
+
+        do {
+            Optimum opt = opts[optCur];
+
+            if (opt.prev1IsLiteral) {
+                opts[optPrev].optPrev = optCur;
+                opts[optPrev].backPrev = -1;
+                optCur = optPrev--;
+
+                if (opt.hasPrev2) {
+                    opts[optPrev].optPrev = optPrev + 1;
+                    opts[optPrev].backPrev = opt.backPrev2;
+                    optCur = optPrev;
+                    optPrev = opt.optPrev2;
+                }
+            }
+
+            int temp = opts[optPrev].optPrev;
+            opts[optPrev].optPrev = optCur;
+            optCur = optPrev;
+            optPrev = temp;
+        } while (optCur > 0);
+
+        optCur = opts[0].optPrev;
+        back = opts[optCur].backPrev;
+        return optCur;
+    }
+
+    int getNextSymbol() {
+        // If there are pending symbols from an earlier call to this
+        // function, return those symbols first.
+        if (optCur < optEnd) {
+            int len = opts[optCur].optPrev - optCur;
+            optCur = opts[optCur].optPrev;
+            back = opts[optCur].backPrev;
+            return len;
+        }
+
+        assert optCur == optEnd;
+        optCur = 0;
+        optEnd = 0;
+        back = -1;
+
+        if (readAhead == -1)
+            matches = getMatches();
+
+        // Get the number of bytes available in the dictionary, but
+        // not more than the maximum match length. If there aren't
+        // enough bytes remaining to encode a match at all, return
+        // immediately to encode this byte as a literal.
+        int avail = Math.min(lz.getAvail(), MATCH_LEN_MAX);
+        if (avail < MATCH_LEN_MIN)
+            return 1;
+
+        // Get the lengths of repeated matches.
+        int repBest = 0;
+        for (int rep = 0; rep < REPS; ++rep) {
+            repLens[rep] = lz.getMatchLen(reps[rep], avail);
+
+            if (repLens[rep] < MATCH_LEN_MIN) {
+                repLens[rep] = 0;
+                continue;
+            }
+
+            if (repLens[rep] > repLens[repBest])
+                repBest = rep;
+        }
+
+        // Return if the best repeated match is at least niceLen bytes long.
+        if (repLens[repBest] >= niceLen) {
+            back = repBest;
+            skip(repLens[repBest] - 1);
+            return repLens[repBest];
+        }
+
+        // Initialize mainLen and mainDist to the longest match found
+        // by the match finder.
+        int mainLen = 0;
+        int mainDist = 0;
+        if (matches.count > 0) {
+            mainLen = matches.len[matches.count - 1];
+            mainDist = matches.dist[matches.count - 1];
+
+            // Return if it is at least niceLen bytes long.
+            if (mainLen >= niceLen) {
+                back = mainDist + REPS;
+                skip(mainLen - 1);
+                return mainLen;
+            }
+        }
+
+        int curByte = lz.getByte(0);
+        int matchByte = lz.getByte(reps[0] + 1);
+
+        // If the match finder found no matches and this byte cannot be
+        // encoded as a repeated match (short or long), we must be return
+        // to have the byte encoded as a literal.
+        if (mainLen < MATCH_LEN_MIN && curByte != matchByte
+                && repLens[repBest] < MATCH_LEN_MIN)
+            return 1;
+
+
+        int pos = lz.getPos();
+        int posState = pos & posMask;
+
+        // Calculate the price of encoding the current byte as a literal.
+        {
+            int prevByte = lz.getByte(1);
+            int literalPrice = literalEncoder.getPrice(curByte, matchByte,
+                                                       prevByte, pos, state);
+            opts[1].set1(literalPrice, 0, -1);
+        }
+
+        int anyMatchPrice = getAnyMatchPrice(state, posState);
+        int anyRepPrice = getAnyRepPrice(anyMatchPrice, state);
+
+        // If it is possible to encode this byte as a short rep, see if
+        // it is cheaper than encoding it as a literal.
+        if (matchByte == curByte) {
+            int shortRepPrice = getShortRepPrice(anyRepPrice,
+                                                 state, posState);
+            if (shortRepPrice < opts[1].price)
+                opts[1].set1(shortRepPrice, 0, 0);
+        }
+
+        // Return if there is neither normal nor long repeated match. Use
+        // a short match instead of a literal if is is possible and cheaper.
+        optEnd = Math.max(mainLen, repLens[repBest]);
+        if (optEnd < MATCH_LEN_MIN) {
+            assert optEnd == 0 : optEnd;
+            back = opts[1].backPrev;
+            return 1;
+        }
+
+
+        // Update the lookup tables for distances and lengths before using
+        // those price calculation functions. (The price function above
+        // don't need these tables.)
+        updatePrices();
+
+        // Initialize the state and reps of this position in opts[].
+        // updateOptStateAndReps() will need these to get the new
+        // state and reps for the next byte.
+        opts[0].state.set(state);
+        System.arraycopy(reps, 0, opts[0].reps, 0, REPS);
+
+        // Initialize the prices for latter opts that will be used below.
+        for (int i = optEnd; i >= MATCH_LEN_MIN; --i)
+            opts[i].reset();
+
+        // Calculate the prices of repeated matches of all lengths.
+        for (int rep = 0; rep < REPS; ++rep) {
+            int repLen = repLens[rep];
+            if (repLen < MATCH_LEN_MIN)
+                continue;
+
+            int longRepPrice = getLongRepPrice(anyRepPrice, rep,
+                                               state, posState);
+            do {
+                int price = longRepPrice + repLenEncoder.getPrice(repLen,
+                                                                  posState);
+                if (price < opts[repLen].price)
+                    opts[repLen].set1(price, 0, rep);
+            } while (--repLen >= MATCH_LEN_MIN);
+        }
+
+        // Calculate the prices of normal matches that are longer than rep0.
+        {
+            int len = Math.max(repLens[0] + 1, MATCH_LEN_MIN);
+            if (len <= mainLen) {
+                int normalMatchPrice = getNormalMatchPrice(anyMatchPrice,
+                                                           state);
+
+                // Set i to the index of the shortest match that is
+                // at least len bytes long.
+                int i = 0;
+                while (len > matches.len[i])
+                    ++i;
+
+                while (true) {
+                    int dist = matches.dist[i];
+                    int price = getMatchAndLenPrice(normalMatchPrice,
+                                                    dist, len, posState);
+                    if (price < opts[len].price)
+                        opts[len].set1(price, 0, dist + REPS);
+
+                    if (len == matches.len[i])
+                        if (++i == matches.count)
+                            break;
+
+                    ++len;
+                }
+            }
+        }
+
+
+        avail = Math.min(lz.getAvail(), OPTS - 1);
+
+        // Get matches for later bytes and optimize the use of LZMA symbols
+        // by calculating the prices and picking the cheapest symbol
+        // combinations.
+        while (++optCur < optEnd) {
+            matches = getMatches();
+            if (matches.count > 0
+                    && matches.len[matches.count - 1] >= niceLen)
+                break;
+
+            --avail;
+            ++pos;
+            posState = pos & posMask;
+
+            updateOptStateAndReps();
+            anyMatchPrice = opts[optCur].price
+                            + getAnyMatchPrice(opts[optCur].state, posState);
+            anyRepPrice = getAnyRepPrice(anyMatchPrice, opts[optCur].state);
+
+            calc1BytePrices(pos, posState, avail, anyRepPrice);
+
+            if (avail >= MATCH_LEN_MIN) {
+                int startLen = calcLongRepPrices(pos, posState,
+                                                 avail, anyRepPrice);
+                if (matches.count > 0)
+                    calcNormalMatchPrices(pos, posState, avail,
+                                          anyMatchPrice, startLen);
+            }
+        }
+
+        return convertOpts();
+    }
+
+    /**
+     * Updates the state and reps for the current byte in the opts array.
+     */
+    private void updateOptStateAndReps() {
+        int optPrev = opts[optCur].optPrev;
+        assert optPrev < optCur;
+
+        if (opts[optCur].prev1IsLiteral) {
+            --optPrev;
+
+            if (opts[optCur].hasPrev2) {
+                opts[optCur].state.set(opts[opts[optCur].optPrev2].state);
+                if (opts[optCur].backPrev2 < REPS)
+                    opts[optCur].state.updateLongRep();
+                else
+                    opts[optCur].state.updateMatch();
+            } else {
+                opts[optCur].state.set(opts[optPrev].state);
+            }
+
+            opts[optCur].state.updateLiteral();
+        } else {
+            opts[optCur].state.set(opts[optPrev].state);
+        }
+
+        if (optPrev == optCur - 1) {
+            // Must be either a short rep or a literal.
+            assert opts[optCur].backPrev == 0 || opts[optCur].backPrev == -1;
+
+            if (opts[optCur].backPrev == 0)
+                opts[optCur].state.updateShortRep();
+            else
+                opts[optCur].state.updateLiteral();
+
+            System.arraycopy(opts[optPrev].reps, 0,
+                             opts[optCur].reps, 0, REPS);
+        } else {
+            int back;
+            if (opts[optCur].prev1IsLiteral && opts[optCur].hasPrev2) {
+                optPrev = opts[optCur].optPrev2;
+                back = opts[optCur].backPrev2;
+                opts[optCur].state.updateLongRep();
+            } else {
+                back = opts[optCur].backPrev;
+                if (back < REPS)
+                    opts[optCur].state.updateLongRep();
+                else
+                    opts[optCur].state.updateMatch();
+            }
+
+            if (back < REPS) {
+                opts[optCur].reps[0] = opts[optPrev].reps[back];
+
+                int rep;
+                for (rep = 1; rep <= back; ++rep)
+                    opts[optCur].reps[rep] = opts[optPrev].reps[rep - 1];
+
+                for (; rep < REPS; ++rep)
+                    opts[optCur].reps[rep] = opts[optPrev].reps[rep];
+            } else {
+                opts[optCur].reps[0] = back - REPS;
+                System.arraycopy(opts[optPrev].reps, 0,
+                                 opts[optCur].reps, 1, REPS - 1);
+            }
+        }
+    }
+
+    /**
+     * Calculates prices of a literal, a short rep, and literal + rep0.
+     */
+    private void calc1BytePrices(int pos, int posState,
+                                 int avail, int anyRepPrice) {
+        // This will be set to true if using a literal or a short rep.
+        boolean nextIsByte = false;
+
+        int curByte = lz.getByte(0);
+        int matchByte = lz.getByte(opts[optCur].reps[0] + 1);
+
+        // Try a literal.
+        int literalPrice = opts[optCur].price
+                + literalEncoder.getPrice(curByte, matchByte, lz.getByte(1),
+                                          pos, opts[optCur].state);
+        if (literalPrice < opts[optCur + 1].price) {
+            opts[optCur + 1].set1(literalPrice, optCur, -1);
+            nextIsByte = true;
+        }
+
+        // Try a short rep.
+        if (matchByte == curByte && (opts[optCur + 1].optPrev == optCur
+                                      || opts[optCur + 1].backPrev != 0)) {
+            int shortRepPrice = getShortRepPrice(anyRepPrice,
+                                                 opts[optCur].state,
+                                                 posState);
+            if (shortRepPrice <= opts[optCur + 1].price) {
+                opts[optCur + 1].set1(shortRepPrice, optCur, 0);
+                nextIsByte = true;
+            }
+        }
+
+        // If neither a literal nor a short rep was the cheapest choice,
+        // try literal + long rep0.
+        if (!nextIsByte && matchByte != curByte && avail > MATCH_LEN_MIN) {
+            int lenLimit = Math.min(niceLen, avail - 1);
+            int len = lz.getMatchLen(1, opts[optCur].reps[0], lenLimit);
+
+            if (len >= MATCH_LEN_MIN) {
+                nextState.set(opts[optCur].state);
+                nextState.updateLiteral();
+                int nextPosState = (pos + 1) & posMask;
+                int price = literalPrice
+                            + getLongRepAndLenPrice(0, len,
+                                                    nextState, nextPosState);
+
+                int i = optCur + 1 + len;
+                while (optEnd < i)
+                    opts[++optEnd].reset();
+
+                if (price < opts[i].price)
+                    opts[i].set2(price, optCur, 0);
+            }
+        }
+    }
+
+    /**
+     * Calculates prices of long rep and long rep + literal + rep0.
+     */
+    private int calcLongRepPrices(int pos, int posState,
+                                  int avail, int anyRepPrice) {
+        int startLen = MATCH_LEN_MIN;
+        int lenLimit = Math.min(avail, niceLen);
+
+        for (int rep = 0; rep < REPS; ++rep) {
+            int len = lz.getMatchLen(opts[optCur].reps[rep], lenLimit);
+            if (len < MATCH_LEN_MIN)
+                continue;
+
+            while (optEnd < optCur + len)
+                opts[++optEnd].reset();
+
+            int longRepPrice = getLongRepPrice(anyRepPrice, rep,
+                                               opts[optCur].state, posState);
+
+            for (int i = len; i >= MATCH_LEN_MIN; --i) {
+                int price = longRepPrice
+                            + repLenEncoder.getPrice(i, posState);
+                if (price < opts[optCur + i].price)
+                    opts[optCur + i].set1(price, optCur, rep);
+            }
+
+            if (rep == 0)
+                startLen = len + 1;
+
+            int len2Limit = Math.min(niceLen, avail - len - 1);
+            int len2 = lz.getMatchLen(len + 1, opts[optCur].reps[rep],
+                                      len2Limit);
+
+            if (len2 >= MATCH_LEN_MIN) {
+                // Rep
+                int price = longRepPrice
+                            + repLenEncoder.getPrice(len, posState);
+                nextState.set(opts[optCur].state);
+                nextState.updateLongRep();
+
+                // Literal
+                int curByte = lz.getByte(len, 0);
+                int matchByte = lz.getByte(0); // lz.getByte(len, len)
+                int prevByte = lz.getByte(len, 1);
+                price += literalEncoder.getPrice(curByte, matchByte, prevByte,
+                                                 pos + len, nextState);
+                nextState.updateLiteral();
+
+                // Rep0
+                int nextPosState = (pos + len + 1) & posMask;
+                price += getLongRepAndLenPrice(0, len2,
+                                               nextState, nextPosState);
+
+                int i = optCur + len + 1 + len2;
+                while (optEnd < i)
+                    opts[++optEnd].reset();
+
+                if (price < opts[i].price)
+                    opts[i].set3(price, optCur, rep, len, 0);
+            }
+        }
+
+        return startLen;
+    }
+
+    /**
+     * Calculates prices of a normal match and normal match + literal + rep0.
+     */
+    private void calcNormalMatchPrices(int pos, int posState, int avail,
+                                       int anyMatchPrice, int startLen) {
+        // If the longest match is so long that it would not fit into
+        // the opts array, shorten the matches.
+        if (matches.len[matches.count - 1] > avail) {
+            matches.count = 0;
+            while (matches.len[matches.count] < avail)
+                ++matches.count;
+
+            matches.len[matches.count++] = avail;
+        }
+
+        if (matches.len[matches.count - 1] < startLen)
+            return;
+
+        while (optEnd < optCur + matches.len[matches.count - 1])
+            opts[++optEnd].reset();
+
+        int normalMatchPrice = getNormalMatchPrice(anyMatchPrice,
+                                                   opts[optCur].state);
+
+        int match = 0;
+        while (startLen > matches.len[match])
+            ++match;
+
+        for (int len = startLen; ; ++len) {
+            int dist = matches.dist[match];
+
+            // Calculate the price of a match of len bytes from the nearest
+            // possible distance.
+            int matchAndLenPrice = getMatchAndLenPrice(normalMatchPrice,
+                                                       dist, len, posState);
+            if (matchAndLenPrice < opts[optCur + len].price)
+                opts[optCur + len].set1(matchAndLenPrice,
+                                        optCur, dist + REPS);
+
+            if (len != matches.len[match])
+                continue;
+
+            // Try match + literal + rep0. First get the length of the rep0.
+            int len2Limit = Math.min(niceLen, avail - len - 1);
+            int len2 = lz.getMatchLen(len + 1, dist, len2Limit);
+
+            if (len2 >= MATCH_LEN_MIN) {
+                nextState.set(opts[optCur].state);
+                nextState.updateMatch();
+
+                // Literal
+                int curByte = lz.getByte(len, 0);
+                int matchByte = lz.getByte(0); // lz.getByte(len, len)
+                int prevByte = lz.getByte(len, 1);
+                int price = matchAndLenPrice
+                        + literalEncoder.getPrice(curByte, matchByte,
+                                                  prevByte, pos + len,
+                                                  nextState);
+                nextState.updateLiteral();
+
+                // Rep0
+                int nextPosState = (pos + len + 1) & posMask;
+                price += getLongRepAndLenPrice(0, len2,
+                                               nextState, nextPosState);
+
+                int i = optCur + len + 1 + len2;
+                while (optEnd < i)
+                    opts[++optEnd].reset();
+
+                if (price < opts[i].price)
+                    opts[i].set3(price, optCur, dist + REPS, len, 0);
+            }
+
+            if (++match == matches.count)
+                break;
+        }
+    }
+}