Add BCJ filters.

20 files changed, 1024 insertions, 0 deletions

diff --git a/src/org/tukaani/xz/ARMOptions.java b/src/org/tukaani/xz/ARMOptions.java
new file mode 100644
index 0000000..e39b831
--- /dev/null
+++ b/src/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 java.io.IOException;
+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) {
+        return new SimpleOutputStream(out, new ARM(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in) {
+        return new SimpleInputStream(in, new ARM(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.ARM_FILTER_ID);
+    }
+}
diff --git a/src/org/tukaani/xz/ARMThumbOptions.java b/src/org/tukaani/xz/ARMThumbOptions.java
new file mode 100644
index 0000000..cddcc4e
--- /dev/null
+++ b/src/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 java.io.IOException;
+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) {
+        return new SimpleOutputStream(out, new ARMThumb(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in) {
+        return new SimpleInputStream(in, new ARMThumb(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.ARMTHUMB_FILTER_ID);
+    }
+}
diff --git a/src/org/tukaani/xz/BCJCoder.java b/src/org/tukaani/xz/BCJCoder.java
new file mode 100644
index 0000000..81862f7
--- /dev/null
+++ b/src/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;
+    }
+}
diff --git a/src/org/tukaani/xz/BCJDecoder.java b/src/org/tukaani/xz/BCJDecoder.java
new file mode 100644
index 0000000..f8a6ae2
--- /dev/null
+++ b/src/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) {
+        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);
+    }
+}
diff --git a/src/org/tukaani/xz/BCJEncoder.java b/src/org/tukaani/xz/BCJEncoder.java
new file mode 100644
index 0000000..f2569d5
--- /dev/null
+++ b/src/org/tukaani/xz/BCJEncoder.java
@@ -0,0 +1,51 @@
+/*
+ * 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;
+
+import java.io.OutputStream;
+import org.tukaani.xz.simple.SimpleFilter;
+
+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) {
+        return options.getOutputStream(out);
+    }
+}
diff --git a/src/org/tukaani/xz/BCJOptions.java b/src/org/tukaani/xz/BCJOptions.java
new file mode 100644
index 0000000..a862154
--- /dev/null
+++ b/src/org/tukaani/xz/BCJOptions.java
@@ -0,0 +1,60 @@
+/*
+ * 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;
+
+import java.io.InputStream;
+import java.io.IOException;
+
+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();
+        }
+    }
+}
diff --git a/src/org/tukaani/xz/BlockInputStream.java b/src/org/tukaani/xz/BlockInputStream.java
index 9ccc02c..0d5897a 100644
--- a/src/org/tukaani/xz/BlockInputStream.java
+++ b/src/org/tukaani/xz/BlockInputStream.java
@@ -126,6 +126,9 @@ class BlockInputStream extends InputStream {
             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]);
diff --git a/src/org/tukaani/xz/IA64Options.java b/src/org/tukaani/xz/IA64Options.java
new file mode 100644
index 0000000..517d2ea
--- /dev/null
+++ b/src/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 java.io.IOException;
+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) {
+        return new SimpleOutputStream(out, new IA64(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in) {
+        return new SimpleInputStream(in, new IA64(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.IA64_FILTER_ID);
+    }
+}
diff --git a/src/org/tukaani/xz/PowerPCOptions.java b/src/org/tukaani/xz/PowerPCOptions.java
new file mode 100644
index 0000000..432b2f0
--- /dev/null
+++ b/src/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 java.io.IOException;
+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) {
+        return new SimpleOutputStream(out, new PowerPC(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in) {
+        return new SimpleInputStream(in, new PowerPC(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.POWERPC_FILTER_ID);
+    }
+}
diff --git a/src/org/tukaani/xz/SPARCOptions.java b/src/org/tukaani/xz/SPARCOptions.java
new file mode 100644
index 0000000..b0ae109
--- /dev/null
+++ b/src/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 java.io.IOException;
+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) {
+        return new SimpleOutputStream(out, new SPARC(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in) {
+        return new SimpleInputStream(in, new SPARC(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.SPARC_FILTER_ID);
+    }
+}
diff --git a/src/org/tukaani/xz/SimpleInputStream.java b/src/org/tukaani/xz/SimpleInputStream.java
new file mode 100644
index 0000000..385b8e4
--- /dev/null
+++ b/src/org/tukaani/xz/SimpleInputStream.java
@@ -0,0 +1,104 @@
+/*
+ * 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 TMPBUF_SIZE = 4096;
+
+    private final InputStream in;
+    private final SimpleFilter simpleFilter;
+
+    private final byte[] tmpbuf = new byte[TMPBUF_SIZE];
+    private int pos = 0;
+    private int filtered = 0;
+    private int unfiltered = 0;
+
+    private boolean endReached = false;
+    private IOException exception = null;
+
+    static int getMemoryUsage() {
+        return 1 + TMPBUF_SIZE / 1024;
+    }
+
+    SimpleInputStream(InputStream in, SimpleFilter simpleFilter) {
+        this.in = in;
+        this.simpleFilter = simpleFilter;
+    }
+
+    public int read() throws IOException {
+        byte[] buf = new byte[1];
+        return read(buf, 0, 1) == -1 ? -1 : (buf[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 IllegalArgumentException();
+
+        if (len == 0)
+            return 0;
+
+        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(tmpbuf, pos, buf, off, copySize);
+                pos += copySize;
+                filtered -= copySize;
+                off += copySize;
+                len -= copySize;
+                size += copySize;
+
+                // If end of tmpbuf was reached, move the pending data to
+                // the beginning of the buffer so that more data can be
+                // copied into tmpbuf on the next loop iteration.
+                if (pos + filtered + unfiltered == TMPBUF_SIZE) {
+                    System.arraycopy(tmpbuf, pos, tmpbuf, 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 = TMPBUF_SIZE - (pos + filtered + unfiltered);
+                inSize = in.read(tmpbuf, 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 tmpbuf.
+                    unfiltered += inSize;
+                    filtered = simpleFilter.code(tmpbuf, pos, unfiltered);
+                    assert filtered <= unfiltered;
+                    unfiltered -= filtered;
+                }
+            }
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+}
diff --git a/src/org/tukaani/xz/SimpleOutputStream.java b/src/org/tukaani/xz/SimpleOutputStream.java
new file mode 100644
index 0000000..f14ffe7
--- /dev/null
+++ b/src/org/tukaani/xz/SimpleOutputStream.java
@@ -0,0 +1,85 @@
+/*
+ * 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 TMPBUF_SIZE = 4096;
+
+    private final FinishableOutputStream out;
+    private final SimpleFilter simpleFilter;
+
+    private final byte[] tmpbuf = new byte[TMPBUF_SIZE];
+    private int pos = 0;
+    private int unfiltered = 0;
+
+    static int getMemoryUsage() {
+        return 1 + TMPBUF_SIZE / 1024;
+    }
+
+    SimpleOutputStream(FinishableOutputStream out,
+                       SimpleFilter simpleFilter) {
+        this.out = out;
+        this.simpleFilter = simpleFilter;
+    }
+
+    public void write(int b) throws IOException {
+        byte[] buf = new byte[1];
+        buf[0] = (byte)b;
+        write(buf, 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 IllegalArgumentException();
+
+        while (len > 0) {
+            // Copy more unfiltered data into tmpbuf.
+            int copySize = Math.min(len, TMPBUF_SIZE - (pos + unfiltered));
+            System.arraycopy(buf, off, tmpbuf, pos + unfiltered, copySize);
+            off += copySize;
+            len -= copySize;
+            unfiltered += copySize;
+
+            // Filter the data in tmpbuf.
+            int filtered = simpleFilter.code(tmpbuf, pos, unfiltered);
+            assert filtered <= unfiltered;
+            unfiltered -= filtered;
+
+            // Write out the filtered data.
+            out.write(tmpbuf, pos, filtered);
+            pos += filtered;
+
+            // If end of tmpbuf was reached, move the pending unfiltered
+            // data to the beginning of the buffer so that more data can
+            // be copied into tmpbuf on the next loop iteration.
+            if (pos + unfiltered == TMPBUF_SIZE) {
+                System.arraycopy(tmpbuf, pos, tmpbuf, 0, unfiltered);
+                pos = 0;
+            }
+        }
+    }
+
+    public void flush() throws IOException {
+        throw new UnsupportedOptionsException("Flushing is not supported");
+    }
+
+    public void finish() throws IOException {
+        out.write(tmpbuf, pos, unfiltered);
+        out.finish();
+    }
+
+    public void close() throws IOException {
+        out.write(tmpbuf, pos, unfiltered);
+        out.close();
+    }
+}
diff --git a/src/org/tukaani/xz/X86Options.java b/src/org/tukaani/xz/X86Options.java
new file mode 100644
index 0000000..9b865dc
--- /dev/null
+++ b/src/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 java.io.IOException;
+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) {
+        return new SimpleOutputStream(out, new X86(true, startOffset));
+    }
+
+    public InputStream getInputStream(InputStream in) {
+        return new SimpleInputStream(in, new X86(false, startOffset));
+    }
+
+    FilterEncoder getFilterEncoder() {
+        return new BCJEncoder(this, BCJCoder.X86_FILTER_ID);
+    }
+}
diff --git a/src/org/tukaani/xz/simple/ARM.java b/src/org/tukaani/xz/simple/ARM.java
new file mode 100644
index 0000000..6febf78
--- /dev/null
+++ b/src/org/tukaani/xz/simple/ARM.java
@@ -0,0 +1,50 @@
+/*
+ * BCJ filter for little endian ARM instructions
+ *
+ * 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.simple;
+
+public final class ARM implements SimpleFilter {
+    private final boolean isEncoder;
+    private int pos;
+
+    public ARM(boolean isEncoder, int startPos) {
+        this.isEncoder = isEncoder;
+        pos = startPos + 8;
+    }
+
+    public int code(byte[] buf, int off, int len) {
+        int end = off + len - 4;
+        int i;
+
+        for (i = off; i <= end; i += 4) {
+            if ((buf[i + 3] & 0xFF) == 0xEB) {
+                int src = ((buf[i + 2] & 0xFF) << 16)
+                          | ((buf[i + 1] & 0xFF) << 8)
+                          | (buf[i] & 0xFF);
+                src <<= 2;
+
+                int dest;
+                if (isEncoder)
+                    dest = src + (pos + i - off);
+                else
+                    dest = src - (pos + i - off);
+
+                dest >>>= 2;
+                buf[i + 2] = (byte)(dest >>> 16);
+                buf[i + 1] = (byte)(dest >>> 8);
+                buf[i] = (byte)dest;
+            }
+        }
+
+        i -= off;
+        pos += i;
+        return i;
+    }
+}
diff --git a/src/org/tukaani/xz/simple/ARMThumb.java b/src/org/tukaani/xz/simple/ARMThumb.java
new file mode 100644
index 0000000..b8e7ca9
--- /dev/null
+++ b/src/org/tukaani/xz/simple/ARMThumb.java
@@ -0,0 +1,53 @@
+/*
+ * BCJ filter for little endian ARM-Thumb instructions
+ *
+ * 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.simple;
+
+public final class ARMThumb implements SimpleFilter {
+    private final boolean isEncoder;
+    private int pos;
+
+    public ARMThumb(boolean isEncoder, int startPos) {
+        this.isEncoder = isEncoder;
+        pos = startPos + 4;
+    }
+
+    public int code(byte[] buf, int off, int len) {
+        int end = off + len - 4;
+        int i;
+
+        for (i = off; i <= end; i += 2) {
+            if ((buf[i + 1] & 0xF8) == 0xF0 && (buf[i + 3] & 0xF8) == 0xF8) {
+                int src = ((buf[i + 1] & 0x07) << 19)
+                          | ((buf[i] & 0xFF) << 11)
+                          | ((buf[i + 3] & 0x07) << 8)
+                          | (buf[i + 2] & 0xFF);
+                src <<= 1;
+
+                int dest;
+                if (isEncoder)
+                    dest = src + (pos + i - off);
+                else
+                    dest = src - (pos + i - off);
+
+                dest >>>= 1;
+                buf[i + 1] = (byte)(0xF0 | ((dest >>> 19) & 0x07));
+                buf[i] = (byte)(dest >>> 11);
+                buf[i + 3] = (byte)(0xF8 | ((dest >>> 8) & 0x07));
+                buf[i + 2] = (byte)dest;
+                i += 2;
+            }
+        }
+
+        i -= off;
+        pos += i;
+        return i;
+    }
+}
diff --git a/src/org/tukaani/xz/simple/IA64.java b/src/org/tukaani/xz/simple/IA64.java
new file mode 100644
index 0000000..776a1b7
--- /dev/null
+++ b/src/org/tukaani/xz/simple/IA64.java
@@ -0,0 +1,81 @@
+/*
+ * BCJ filter for Itanium (IA-64) instructions
+ *
+ * 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.simple;
+
+public final class IA64 implements SimpleFilter {
+    private static final int[] BRANCH_TABLE = {
+            0, 0, 0, 0, 0, 0, 0, 0,
+            0, 0, 0, 0, 0, 0, 0, 0,
+            4, 4, 6, 6, 0, 0, 7, 7,
+            4, 4, 0, 0, 4, 4, 0, 0 };
+
+    private final boolean isEncoder;
+    private int pos;
+
+    public IA64(boolean isEncoder, int startPos) {
+        this.isEncoder = isEncoder;
+        pos = startPos;
+    }
+
+    public int code(byte[] buf, int off, int len) {
+        int end = off + len - 16;
+        int i;
+
+        for (i = off; i <= end; i += 16) {
+            int instrTemplate = buf[i] & 0x1F;
+            int mask = BRANCH_TABLE[instrTemplate];
+
+            for (int slot = 0, bitPos = 5; slot < 3; ++slot, bitPos += 41) {
+                if (((mask >>> slot) & 1) == 0)
+                    continue;
+
+                int bytePos = bitPos >>> 3;
+                int bitRes = bitPos & 7;
+
+                long instr = 0;
+                for (int j = 0; j < 6; ++j)
+                    instr |= (buf[i + bytePos + j] & 0xFFL) << (8 * j);
+
+                long instrNorm = instr >>> bitRes;
+
+                if (((instrNorm >>> 37) & 0x0F) != 0x05
+                        || ((instrNorm >>> 9) & 0x07) != 0x00)
+                    continue;
+
+                int src = (int)((instrNorm >>> 13) & 0x0FFFFF);
+                src |= ((int)(instrNorm >>> 36) & 1) << 20;
+                src <<= 4;
+
+                int dest;
+                if (isEncoder)
+                    dest = src + (pos + i - off);
+                else
+                    dest = src - (pos + i - off);
+
+                dest >>>= 4;
+
+                instrNorm &= ~(0x8FFFFFL << 13);
+                instrNorm |= (dest & 0x0FFFFFL) << 13;
+                instrNorm |= (dest & 0x100000L) << (36 - 20);
+
+                instr &= (1 << bitRes) - 1;
+                instr |= instrNorm << bitRes;
+
+                for (int j = 0; j < 6; ++j)
+                    buf[i + bytePos + j] = (byte)(instr >>> (8 * j));
+            }
+        }
+
+        i -= off;
+        pos += i;
+        return i;
+    }
+}
diff --git a/src/org/tukaani/xz/simple/PowerPC.java b/src/org/tukaani/xz/simple/PowerPC.java
new file mode 100644
index 0000000..b7400ab
--- /dev/null
+++ b/src/org/tukaani/xz/simple/PowerPC.java
@@ -0,0 +1,50 @@
+/*
+ * BCJ filter for big endian PowerPC instructions
+ *
+ * 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.simple;
+
+public final class PowerPC implements SimpleFilter {
+    private final boolean isEncoder;
+    private int pos;
+
+    public PowerPC(boolean isEncoder, int startPos) {
+        this.isEncoder = isEncoder;
+        pos = startPos;
+    }
+
+    public int code(byte[] buf, int off, int len) {
+        int end = off + len - 4;
+        int i;
+
+        for (i = off; i <= end; i += 4) {
+            if ((buf[i] & 0xFC) == 0x48 && (buf[i + 3] & 0x03) == 0x01) {
+                int src = ((buf[i] & 0x03) << 24)
+                          | ((buf[i + 1] & 0xFF) << 16)
+                          | ((buf[i + 2] & 0xFF) << 8)
+                          | (buf[i + 3] & 0xFC);
+
+                int dest;
+                if (isEncoder)
+                    dest = src + (pos + i - off);
+                else
+                    dest = src - (pos + i - off);
+
+                buf[i] = (byte)(0x48 | ((dest >>> 24) & 0x03));
+                buf[i + 1] = (byte)(dest >>> 16);
+                buf[i + 2] = (byte)(dest >>> 8);
+                buf[i + 3] = (byte)((buf[i + 3] & 0x03) | dest);
+            }
+        }
+
+        i -= off;
+        pos += i;
+        return i;
+    }
+}
diff --git a/src/org/tukaani/xz/simple/SPARC.java b/src/org/tukaani/xz/simple/SPARC.java
new file mode 100644
index 0000000..913c8ac
--- /dev/null
+++ b/src/org/tukaani/xz/simple/SPARC.java
@@ -0,0 +1,56 @@
+/*
+ * BCJ filter for SPARC instructions
+ *
+ * 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.simple;
+
+public final class SPARC implements SimpleFilter {
+    private final boolean isEncoder;
+    private int pos;
+
+    public SPARC(boolean isEncoder, int startPos) {
+        this.isEncoder = isEncoder;
+        pos = startPos;
+    }
+
+    public int code(byte[] buf, int off, int len) {
+        int end = off + len - 4;
+        int i;
+
+        for (i = off; i <= end; i += 4) {
+            if ((buf[i] == 0x40 && (buf[i + 1] & 0xC0) == 0x00)
+                    || (buf[i] == 0x7F && (buf[i + 1] & 0xC0) == 0xC0)) {
+                int src = ((buf[i] & 0xFF) << 24)
+                          | ((buf[i + 1] & 0xFF) << 16)
+                          | ((buf[i + 2] & 0xFF) << 8)
+                          | (buf[i + 3] & 0xFF);
+                src <<= 2;
+
+                int dest;
+                if (isEncoder)
+                    dest = src + (pos + i - off);
+                else
+                    dest = src - (pos + i - off);
+
+                dest >>>= 2;
+                dest = (((0 - ((dest >>> 22) & 1)) << 22) & 0x3FFFFFFF)
+                       | (dest & 0x3FFFFF) | 0x40000000;
+
+                buf[i] = (byte)(dest >>> 24);
+                buf[i + 1] = (byte)(dest >>> 16);
+                buf[i + 2] = (byte)(dest >>> 8);
+                buf[i + 3] = (byte)dest;
+            }
+        }
+
+        i -= off;
+        pos += i;
+        return i;
+    }
+}
diff --git a/src/org/tukaani/xz/simple/SimpleFilter.java b/src/org/tukaani/xz/simple/SimpleFilter.java
new file mode 100644
index 0000000..6f72906
--- /dev/null
+++ b/src/org/tukaani/xz/simple/SimpleFilter.java
@@ -0,0 +1,14 @@
+/*
+ * BCJ filter for little endian ARM instructions
+ *
+ * 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.simple;
+
+public interface SimpleFilter {
+    int code(byte[] buf, int off, int len);
+}
diff --git a/src/org/tukaani/xz/simple/X86.java b/src/org/tukaani/xz/simple/X86.java
new file mode 100644
index 0000000..a05e08b
--- /dev/null
+++ b/src/org/tukaani/xz/simple/X86.java
@@ -0,0 +1,98 @@
+/*
+ * BCJ filter for x86 instructions
+ *
+ * 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.simple;
+
+public final class X86 implements SimpleFilter {
+    private static final boolean[] MASK_TO_ALLOWED_STATUS
+            = {true, true, true, false, true, false, false, false};
+
+    private static final int[] MASK_TO_BIT_NUMBER = {0, 1, 2, 2, 3, 3, 3, 3};
+
+    private final boolean isEncoder;
+    private int pos;
+    private int prevMask = 0;
+
+    private static boolean test86MSByte(byte b) {
+        int i = b & 0xFF;
+        return i == 0x00 || i == 0xFF;
+    }
+
+    public X86(boolean isEncoder, int startPos) {
+        this.isEncoder = isEncoder;
+        pos = startPos + 5;
+    }
+
+    public int code(byte[] buf, int off, int len) {
+        int prevPos = off - 1;
+        int end = off + len - 5;
+        int i;
+
+        for (i = off; i <= end; ++i) {
+            if ((buf[i] & 0xFE) != 0xE8)
+                continue;
+
+            prevPos = i - prevPos;
+            if ((prevPos & ~3) != 0) { // (unsigned)prevPos > 3
+                prevMask = 0;
+            } else {
+                prevMask = (prevMask << (prevPos - 1)) & 7;
+                if (prevMask != 0) {
+                    if (!MASK_TO_ALLOWED_STATUS[prevMask] || test86MSByte(
+                            buf[i + 4 - MASK_TO_BIT_NUMBER[prevMask]])) {
+                        prevPos = i;
+                        prevMask = (prevMask << 1) | 1;
+                        continue;
+                    }
+                }
+            }
+
+            prevPos = i;
+
+            if (test86MSByte(buf[i + 4])) {
+                int src = (buf[i + 1] & 0xFF)
+                          | ((buf[i + 2] & 0xFF) << 8)
+                          | ((buf[i + 3] & 0xFF) << 16)
+                          | ((buf[i + 4] & 0xFF) << 24);
+                int dest;
+                while (true) {
+                    if (isEncoder)
+                        dest = src + (pos + i - off);
+                    else
+                        dest = src - (pos + i - off);
+
+                    if (prevMask == 0)
+                        break;
+
+                    int index = MASK_TO_BIT_NUMBER[prevMask] * 8;
+                    if (!test86MSByte((byte)(dest >>> (24 - index))))
+                        break;
+
+                    src = dest ^ ((1 << (32 - index)) - 1);
+                }
+
+                buf[i + 1] = (byte)dest;
+                buf[i + 2] = (byte)(dest >>> 8);
+                buf[i + 3] = (byte)(dest >>> 16);
+                buf[i + 4] = (byte)(~(((dest >>> 24) & 1) - 1));
+                i += 4;
+            } else {
+                prevMask = (prevMask << 1) | 1;
+            }
+        }
+
+        prevPos = i - prevPos;
+        prevMask = ((prevPos & ~3) != 0) ? 0 : prevMask << (prevPos - 1);
+
+        i -= off;
+        pos += i;
+        return i;
+    }
+}