/*
LZ4 - Java port of Fast LZ compression algorithm
Copyright (C) 2011-2015, Yann Collet.
Copyright (C) 2015, Odnoklassniki Ltd, Mail.Ru Group.
BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following disclaimer
in the documentation and/or other materials provided with the
distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package one.nio.lz4;
import one.nio.os.NativeLibrary;
import static one.nio.util.JavaInternals.*;
public class LZ4 {
private static final int LZ4_MAX_INPUT_SIZE = 0x7E000000;
private static final int LZ4_MEMORY_USAGE = 15;
private static final int ACCELERATION = 1;
private static final int MINMATCH = 4;
private static final int COPYLENGTH = 8;
private static final int LASTLITERALS = 5;
private static final int MFLIMIT = COPYLENGTH + MINMATCH;
private static final int LZ4_MIN_LENGTH = MFLIMIT + 1;
private static final int MAXD_LOG = 16;
private static final int MAX_DISTANCE = (1 << MAXD_LOG) - 1;
private static final int ML_BITS = 4;
private static final int ML_MASK = (1 << ML_BITS) - 1;
private static final int RUN_BITS = 8 - ML_BITS;
private static final int RUN_MASK = (1 << RUN_BITS) - 1;
private static final int HASH_SIZE_16 = 1 << (LZ4_MEMORY_USAGE - 1);
private static final int HASH_SIZE_32 = 1 << (LZ4_MEMORY_USAGE - 2);
private static final int LZ4_SKIP_TRIGGER = 6;
private static final int LZ4_64K_LIMIT = 65536 + (MFLIMIT - 1);
private static final long DEC64_TABLE = 0x03020100ff000000L;
private static final long DEC32_TABLE = 0x0404040401020104L;
// Public API
public static int compressBound(int size) {
return size + size / 255 + 16;
}
public static int compress(byte[] src, byte[] dst) {
return compress(src, 0, dst, 0, src.length);
}
public static int compress(byte[] src, int srcOffset, byte[] dst, int dstOffset, int length) {
if (srcOffset < 0 || srcOffset + length > src.length || dstOffset < 0 || length < 0) {
throw new IndexOutOfBoundsException();
}
if (dstOffset + compressBound(length) > dst.length) {
throw new IllegalArgumentException("Output array is too small");
}
if (NativeLibrary.IS_SUPPORTED) {
return compress0(src, srcOffset, dst, dstOffset, length);
} else if (length < LZ4_64K_LIMIT) {
return compress16(src, byteArrayOffset + srcOffset, dst, byteArrayOffset + dstOffset, length);
} else if (length <= LZ4_MAX_INPUT_SIZE) {
return compress32(src, byteArrayOffset + srcOffset, dst, byteArrayOffset + dstOffset, length);
} else {
throw new IllegalArgumentException("Input exceeds limit");
}
}
public static int decompress(byte[] src, byte[] dst) {
return decompress(src, 0, dst, 0, src.length);
}
public static int decompress(byte[] src, int srcOffset, byte[] dst, int dstOffset, int length) {
if (srcOffset < 0 || srcOffset + length > src.length || dstOffset < 0 || length <= 0) {
throw new IndexOutOfBoundsException();
}
int result;
if (NativeLibrary.IS_SUPPORTED) {
result = decompress0(src, srcOffset, dst, dstOffset, length);
} else {
result = decompress(src, byteArrayOffset + srcOffset, dst, byteArrayOffset + dstOffset, length, dst.length - dstOffset);
}
if (result < 0) {
throw new IllegalArgumentException("Malformed input");
}
return result;
}
// Compression implementation
private static int hashPosition16(Object src, long p) {
long sequence = unsafe.getLong(src, p);
return (int) ((sequence * 889523592379L) >>> (41 - LZ4_MEMORY_USAGE)) & (HASH_SIZE_16 - 1);
}
private static int hashPosition32(Object src, long p) {
long sequence = unsafe.getLong(src, p);
return (int) ((sequence * 889523592379L) >>> (42 - LZ4_MEMORY_USAGE)) & (HASH_SIZE_32 - 1);
}
private static void putPosition(short[] table, long p, Object src, long srcOffset) {
int h = hashPosition16(src, p);
table[h] = (short) (p - srcOffset);
}
private static long replacePosition(short[] table, long p, Object src, long srcOffset) {
int h = hashPosition16(src, p);
long prev = (table[h] & 0xffffL) + srcOffset;
table[h] = (short) (p - srcOffset);
return prev;
}
private static void putPosition(int[] table, long p, Object src, long srcOffset) {
int h = hashPosition32(src, p);
table[h] = (int) (p - srcOffset);
}
private static long replacePosition(int[] table, long p, Object src, long srcOffset) {
int h = hashPosition32(src, p);
long prev = (table[h] & 0xffffffffL) + srcOffset;
table[h] = (int) (p - srcOffset);
return prev;
}
private static int matchLength(Object src, long pIn, long pMatch, long pInLimit) {
final long pStart = pIn;
while (pIn < pInLimit - 7) {
long diff = unsafe.getLong(src, pMatch) ^ unsafe.getLong(src, pIn);
if (diff != 0) {
pIn += Long.numberOfTrailingZeros(diff) >>> 3;
return (int) (pIn - pStart);
}
pIn += 8;
pMatch += 8;
}
if (pIn < pInLimit - 3 && unsafe.getInt(src, pMatch) == unsafe.getInt(src, pIn)) {
pIn += 4;
pMatch += 4;
}
if (pIn < pInLimit - 1 && unsafe.getShort(src, pMatch) == unsafe.getShort(src, pIn)) {
pIn += 2;
pMatch += 2;
}
if (pIn < pInLimit && unsafe.getByte(src, pMatch) == unsafe.getByte(src, pIn)) {
pIn++;
}
return (int) (pIn - pStart);
}
private static void wildCopy(Object src, long srcOffset, Object dst, long dstOffset, long dstEnd) {
do {
unsafe.putLong(dst, dstOffset, unsafe.getLong(src, srcOffset));
dstOffset += 8;
srcOffset += 8;
} while (dstOffset < dstEnd);
}
private static int compress16(final Object src, final long srcOffset,
final Object dst, final long dstOffset,
final int inputSize) {
final long srcEnd = srcOffset + inputSize;
final long mfLimit = srcEnd - MFLIMIT;
final long matchLimit = srcEnd - LASTLITERALS;
long ip = srcOffset;
long anchor = srcOffset;
long op = dstOffset;
if (inputSize >= LZ4_MIN_LENGTH) {
final short[] table = new short[HASH_SIZE_16];
// First Byte
putPosition(table, ip, src, srcOffset);
ip++;
int forwardH = hashPosition16(src, ip);
mainLoop:
for (; ; ) {
long match;
long token;
{
long forwardIp = ip;
int step = 1;
int searchMatchNb = ACCELERATION << LZ4_SKIP_TRIGGER;
// Find a match
do {
int h = forwardH;
ip = forwardIp;
forwardIp += step;
step = (searchMatchNb++ >>> LZ4_SKIP_TRIGGER);
if (forwardIp > mfLimit) break mainLoop;
match = (table[h] & 0xffffL) + srcOffset;
forwardH = hashPosition16(src, forwardIp);
table[h] = (short) (ip - srcOffset);
} while (unsafe.getInt(src, match) != unsafe.getInt(src, ip));
}
// Catch up
while (ip > anchor && match > srcOffset && unsafe.getByte(src, ip - 1) == unsafe.getByte(src, match - 1)) {
ip--;
match--;
}
{
// Encode Literal length
int litLength = (int) (ip - anchor);
token = op++;
if (litLength >= RUN_MASK) {
int len = litLength - RUN_MASK;
unsafe.putByte(dst, token, (byte) (RUN_MASK << ML_BITS));
for (; len >= 255; len -= 255) {
unsafe.putByte(dst, op++, (byte) 0xff);
}
unsafe.putByte(dst, op++, (byte) len);
} else {
unsafe.putByte(dst, token, (byte) (litLength << ML_BITS));
}
// Copy Literals
wildCopy(src, anchor, dst, op, op + litLength);
op += litLength;
}
for (; ; ) {
// Encode Offset
unsafe.putShort(dst, op, (short) (ip - match));
op += 2;
// Encode MatchLength
{
int matchLength = matchLength(src, ip + MINMATCH, match + MINMATCH, matchLimit);
ip += MINMATCH + matchLength;
if (matchLength >= ML_MASK) {
unsafe.putByte(dst, token, (byte) (unsafe.getByte(dst, token) + ML_MASK));
matchLength -= ML_MASK;
for (; matchLength >= 510; matchLength -= 510) {
unsafe.putShort(dst, op, (short) 0xffff);
op += 2;
}
if (matchLength >= 255) {
matchLength -= 255;
unsafe.putByte(dst, op++, (byte) 0xff);
}
unsafe.putByte(dst, op++, (byte) matchLength);
} else {
unsafe.putByte(dst, token, (byte) (unsafe.getByte(dst, token) + matchLength));
}
}
anchor = ip;
// Test end of chunk
if (ip > mfLimit) break mainLoop;
// Fill table
putPosition(table, ip - 2, src, srcOffset);
// Test next position
match = replacePosition(table, ip, src, srcOffset);
if (match + MAX_DISTANCE >= ip && unsafe.getInt(src, match) == unsafe.getInt(src, ip)) {
token = op++;
unsafe.putByte(dst, token, (byte) 0);
continue;
}
// Prepare next loop
forwardH = hashPosition16(src, ++ip);
break;
}
} // mainLoop
} // if (inputSize >= LZ4_MIN_LENGTH)
// Encode Last Literals
{
int lastRun = (int) (srcEnd - anchor);
if (lastRun >= RUN_MASK) {
int accumulator = lastRun - RUN_MASK;
unsafe.putByte(dst, op++, (byte) (RUN_MASK << ML_BITS));
for (; accumulator >= 255; accumulator -= 255) {
unsafe.putByte(dst, op++, (byte) 0xff);
}
unsafe.putByte(dst, op++, (byte) accumulator);
} else {
unsafe.putByte(dst, op++, (byte) (lastRun << ML_BITS));
}
unsafe.copyMemory(src, anchor, dst, op, lastRun);
op += lastRun;
}
return (int) (op - dstOffset);
}
private static int compress32(final Object src, final long srcOffset,
final Object dst, final long dstOffset,
final int inputSize) {
final long srcEnd = srcOffset + inputSize;
final long mfLimit = srcEnd - MFLIMIT;
final long matchLimit = srcEnd - LASTLITERALS;
long ip = srcOffset;
long anchor = srcOffset;
long op = dstOffset;
if (inputSize >= LZ4_MIN_LENGTH) {
final int[] table = new int[HASH_SIZE_32];
// First Byte
putPosition(table, ip, src, srcOffset);
ip++;
int forwardH = hashPosition32(src, ip);
mainLoop:
for (; ; ) {
long match;
long token;
{
long forwardIp = ip;
int step = 1;
int searchMatchNb = ACCELERATION << LZ4_SKIP_TRIGGER;
// Find a match
do {
int h = forwardH;
ip = forwardIp;
forwardIp += step;
step = (searchMatchNb++ >>> LZ4_SKIP_TRIGGER);
if (forwardIp > mfLimit) break mainLoop;
match = (table[h] & 0xffffffffL) + srcOffset;
forwardH = hashPosition32(src, forwardIp);
table[h] = (int) (ip - srcOffset);
} while (match + MAX_DISTANCE < ip || unsafe.getInt(src, match) != unsafe.getInt(src, ip));
}
// Catch up
while (ip > anchor && match > srcOffset && unsafe.getByte(src, ip - 1) == unsafe.getByte(src, match - 1)) {
ip--;
match--;
}
{
// Encode Literal length
int litLength = (int) (ip - anchor);
token = op++;
if (litLength >= RUN_MASK) {
int len = litLength - RUN_MASK;
unsafe.putByte(dst, token, (byte) (RUN_MASK << ML_BITS));
for (; len >= 255; len -= 255) {
unsafe.putByte(dst, op++, (byte) 0xff);
}
unsafe.putByte(dst, op++, (byte) len);
} else {
unsafe.putByte(dst, token, (byte) (litLength << ML_BITS));
}
// Copy Literals
wildCopy(src, anchor, dst, op, op + litLength);
op += litLength;
}
for (; ; ) {
// Encode Offset
unsafe.putShort(dst, op, (short) (ip - match));
op += 2;
// Encode MatchLength
{
int matchLength = matchLength(src, ip + MINMATCH, match + MINMATCH, matchLimit);
ip += MINMATCH + matchLength;
if (matchLength >= ML_MASK) {
unsafe.putByte(dst, token, (byte) (unsafe.getByte(dst, token) + ML_MASK));
matchLength -= ML_MASK;
for (; matchLength >= 510; matchLength -= 510) {
unsafe.putShort(dst, op, (short) 0xffff);
op += 2;
}
if (matchLength >= 255) {
matchLength -= 255;
unsafe.putByte(dst, op++, (byte) 0xff);
}
unsafe.putByte(dst, op++, (byte) matchLength);
} else {
unsafe.putByte(dst, token, (byte) (unsafe.getByte(dst, token) + matchLength));
}
}
anchor = ip;
// Test end of chunk
if (ip > mfLimit) break mainLoop;
// Fill table
putPosition(table, ip - 2, src, srcOffset);
// Test next position
match = replacePosition(table, ip, src, srcOffset);
if (match + MAX_DISTANCE >= ip && unsafe.getInt(src, match) == unsafe.getInt(src, ip)) {
token = op++;
unsafe.putByte(dst, token, (byte) 0);
continue;
}
// Prepare next loop
forwardH = hashPosition32(src, ++ip);
break;
}
} // mainLoop
} // if (inputSize >= LZ4_MIN_LENGTH)
// Encode Last Literals
{
int lastRun = (int) (srcEnd - anchor);
if (lastRun >= RUN_MASK) {
int accumulator = lastRun - RUN_MASK;
unsafe.putByte(dst, op++, (byte) (RUN_MASK << ML_BITS));
for (; accumulator >= 255; accumulator -= 255) {
unsafe.putByte(dst, op++, (byte) 0xff);
}
unsafe.putByte(dst, op++, (byte) accumulator);
} else {
unsafe.putByte(dst, op++, (byte) (lastRun << ML_BITS));
}
unsafe.copyMemory(src, anchor, dst, op, lastRun);
op += lastRun;
}
return (int) (op - dstOffset);
}
// Decompression implementation
private static int decompress(final Object src, final long srcOffset,
final Object dst, final long dstOffset,
final int inputSize, final int outputSize) {
final long srcEnd = srcOffset + inputSize;
final long dstEnd = dstOffset + outputSize;
long ip = srcOffset;
long op = dstOffset;
// Special case
if (outputSize == 0) {
return inputSize == 1 && unsafe.getByte(src, ip) == 0 ? 0 : -1;
}
for (; ; ) {
// Get literal length
int token = unsafe.getByte(src, ip++) & 0xff;
int length = token >>> ML_BITS;
if (length == RUN_MASK) {
int s;
do {
s = unsafe.getByte(src, ip++) & 0xff;
length += s;
} while (ip < srcEnd - RUN_MASK && s == 255);
if (length < 0) return -1; // Error: overflow
}
// Copy literals
long cpy = op + length;
if (cpy > dstEnd - MFLIMIT || ip + length > srcEnd - (2 + 1 + LASTLITERALS)) {
if (ip + length != srcEnd || cpy > dstEnd) return -1; // Error: input must be consumed
unsafe.copyMemory(src, ip, dst, op, length);
op += length;
return (int) (op - dstOffset);
}
wildCopy(src, ip, dst, op, cpy);
ip += length;
op = cpy;
// Get offset
long match = cpy - (unsafe.getShort(src, ip) & 0xffff);
ip += 2;
if (match < dstOffset) return -1; // Error: offset outside destination buffer
// Get matchlength
length = token & ML_MASK;
if (length == ML_MASK) {
int s;
do {
if (ip > srcEnd - LASTLITERALS) return -1;
s = unsafe.getByte(src, ip++) & 0xff;
length += s;
} while (s == 255);
if (length < 0) return -1; // Error: overflow
}
length += MINMATCH;
// Copy repeated sequence
cpy = op + length;
if (op - match < 8) {
byte dec64 = (byte) (DEC64_TABLE >>> (op - match) * 8);
unsafe.putByte(dst, op, unsafe.getByte(dst, match));
unsafe.putByte(dst, op + 1, unsafe.getByte(dst, match + 1));
unsafe.putByte(dst, op + 2, unsafe.getByte(dst, match + 2));
unsafe.putByte(dst, op + 3, unsafe.getByte(dst, match + 3));
match += (byte) (DEC32_TABLE >>> (op - match) * 8);
unsafe.putInt(dst, op + 4, unsafe.getInt(dst, match));
op += 8;
match -= dec64;
} else {
unsafe.putLong(dst, op, unsafe.getLong(dst, match));
op += 8;
match += 8;
}
if (cpy > dstEnd - 12) {
if (cpy > dstEnd - LASTLITERALS) return -1; // Error: last LASTLITERALS bytes must be literals
if (op < dstEnd - 8) {
wildCopy(dst, match, dst, op, dstEnd - 8);
match += (dstEnd - 8) - op;
op = dstEnd - 8;
}
while (op < cpy) {
unsafe.putByte(dst, op++, unsafe.getByte(dst, match++));
}
} else {
wildCopy(dst, match, dst, op, cpy);
}
op = cpy; // correction
}
}
// JNI implementation
private static native int compress0(byte[] src, int srcOffset, byte[] dst, int dstOffset, int length);
private static native int decompress0(byte[] src, int srcOffset, byte[] dst, int dstOffset, int length);
}