com.moilioncircle.redis.replicator.util.Lzf Maven / Gradle / Ivy
/*
* Copyright 2009-2010 Ning, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.moilioncircle.redis.replicator.util;
/**
* @author Ning
* @author Leon Chen
* @see VanillaChunkDecoder.java
* @see VanillaChunkEncoder.java
* @since 2.1.0
*/
public class Lzf {
private static final int MAX_OFF = 1 << 13;
private static final int HASH_SIZE = 1 << 14;
private static final int MAX_LITERAL = 1 << 5;
private static final int MAX_REF = (1 << 8) + (1 << 3);
private static final ThreadLocal BUFFER = ThreadLocal.withInitial(() -> new long[HASH_SIZE]);
public static ByteArray decode(ByteArray bytes, long len) {
ByteArray out = new ByteArray(len);
decode(bytes, 0, out, 0, len);
return out;
}
private static void decode(ByteArray in, long inPos, ByteArray out, long outPos, long outEnd) {
do {
int ctrl = in.get(inPos++) & 255;
if (ctrl < 1 << 5) {
switch (ctrl) {
case 31:
out.set(outPos++, in.get(inPos++));
case 30:
out.set(outPos++, in.get(inPos++));
case 29:
out.set(outPos++, in.get(inPos++));
case 28:
out.set(outPos++, in.get(inPos++));
case 27:
out.set(outPos++, in.get(inPos++));
case 26:
out.set(outPos++, in.get(inPos++));
case 25:
out.set(outPos++, in.get(inPos++));
case 24:
out.set(outPos++, in.get(inPos++));
case 23:
out.set(outPos++, in.get(inPos++));
case 22:
out.set(outPos++, in.get(inPos++));
case 21:
out.set(outPos++, in.get(inPos++));
case 20:
out.set(outPos++, in.get(inPos++));
case 19:
out.set(outPos++, in.get(inPos++));
case 18:
out.set(outPos++, in.get(inPos++));
case 17:
out.set(outPos++, in.get(inPos++));
case 16:
out.set(outPos++, in.get(inPos++));
case 15:
out.set(outPos++, in.get(inPos++));
case 14:
out.set(outPos++, in.get(inPos++));
case 13:
out.set(outPos++, in.get(inPos++));
case 12:
out.set(outPos++, in.get(inPos++));
case 11:
out.set(outPos++, in.get(inPos++));
case 10:
out.set(outPos++, in.get(inPos++));
case 9:
out.set(outPos++, in.get(inPos++));
case 8:
out.set(outPos++, in.get(inPos++));
case 7:
out.set(outPos++, in.get(inPos++));
case 6:
out.set(outPos++, in.get(inPos++));
case 5:
out.set(outPos++, in.get(inPos++));
case 4:
out.set(outPos++, in.get(inPos++));
case 3:
out.set(outPos++, in.get(inPos++));
case 2:
out.set(outPos++, in.get(inPos++));
case 1:
out.set(outPos++, in.get(inPos++));
case 0:
out.set(outPos++, in.get(inPos++));
}
continue;
}
long len = ctrl >> 5;
ctrl = -((ctrl & 0x1F) << 8) - 1;
if (len < 7) {
ctrl -= in.get(inPos++) & 255;
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
switch ((int) len) {
case 6:
out.set(outPos, out.get(outPos++ + ctrl));
case 5:
out.set(outPos, out.get(outPos++ + ctrl));
case 4:
out.set(outPos, out.get(outPos++ + ctrl));
case 3:
out.set(outPos, out.get(outPos++ + ctrl));
case 2:
out.set(outPos, out.get(outPos++ + ctrl));
case 1:
out.set(outPos, out.get(outPos++ + ctrl));
}
continue;
}
len = in.get(inPos++) & 255;
ctrl -= in.get(inPos++) & 255;
if ((ctrl + len) < -9) {
len += 9;
if (len <= 32) {
long inPos1 = outPos + ctrl;
long outPos1 = outPos;
switch ((int) len - 1) {
case 31:
out.set(outPos1++, out.get(inPos1++));
case 30:
out.set(outPos1++, out.get(inPos1++));
case 29:
out.set(outPos1++, out.get(inPos1++));
case 28:
out.set(outPos1++, out.get(inPos1++));
case 27:
out.set(outPos1++, out.get(inPos1++));
case 26:
out.set(outPos1++, out.get(inPos1++));
case 25:
out.set(outPos1++, out.get(inPos1++));
case 24:
out.set(outPos1++, out.get(inPos1++));
case 23:
out.set(outPos1++, out.get(inPos1++));
case 22:
out.set(outPos1++, out.get(inPos1++));
case 21:
out.set(outPos1++, out.get(inPos1++));
case 20:
out.set(outPos1++, out.get(inPos1++));
case 19:
out.set(outPos1++, out.get(inPos1++));
case 18:
out.set(outPos1++, out.get(inPos1++));
case 17:
out.set(outPos1++, out.get(inPos1++));
case 16:
out.set(outPos1++, out.get(inPos1++));
case 15:
out.set(outPos1++, out.get(inPos1++));
case 14:
out.set(outPos1++, out.get(inPos1++));
case 13:
out.set(outPos1++, out.get(inPos1++));
case 12:
out.set(outPos1++, out.get(inPos1++));
case 11:
out.set(outPos1++, out.get(inPos1++));
case 10:
out.set(outPos1++, out.get(inPos1++));
case 9:
out.set(outPos1++, out.get(inPos1++));
case 8:
out.set(outPos1++, out.get(inPos1++));
case 7:
out.set(outPos1++, out.get(inPos1++));
case 6:
out.set(outPos1++, out.get(inPos1++));
case 5:
out.set(outPos1++, out.get(inPos1++));
case 4:
out.set(outPos1++, out.get(inPos1++));
case 3:
out.set(outPos1++, out.get(inPos1++));
case 2:
out.set(outPos1++, out.get(inPos1++));
case 1:
out.set(outPos1++, out.get(inPos1++));
case 0:
out.set(outPos1++, out.get(inPos1++));
}
} else {
ByteArray.arraycopy(out, outPos + ctrl, out, outPos, len);
}
outPos += len;
continue;
}
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
len += outPos;
final long end = len - 3;
while (outPos < end) {
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
}
if (len - outPos == 3) {
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
} else if (len - outPos == 2) {
out.set(outPos, out.get(outPos++ + ctrl));
out.set(outPos, out.get(outPos++ + ctrl));
} else if (len - outPos == 1) {
out.set(outPos, out.get(outPos++ + ctrl));
}
} while (outPos < outEnd);
if (outPos != outEnd) {
throw new AssertionError("corrupt data: overrun in decompress, input offset " + inPos + ", output offset " + outPos);
}
}
public static ByteArray encode(ByteArray bytes) {
long len = bytes.length();
ByteArray out = new ByteArray(len - 3);
len = encode(bytes, len, out, 0);
if (len <= 0) {
return bytes;
} else {
ByteArray r = new ByteArray(len);
ByteArray.arraycopy(out, 0, r, 0, len);
return r;
}
}
public static long encode(ByteArray in, long inLen, ByteArray out, long outPos) {
try {
int inPos = 0;
long outLen = outPos + out.length() - 1;
long[] hashTab = BUFFER.get();
java.util.Arrays.fill(hashTab, 0);
int literals = 0;
outPos++;
int future = first(in, 0);
while (inPos < inLen - 4) {
byte p2 = in.get(inPos + 2);
// next
future = (future << 8) + (p2 & 255);
int off = hash(future);
long ref = hashTab[off];
hashTab[off] = inPos;
// if (ref < inPos
// && ref > 0
// && (off = inPos - ref - 1) < MAX_OFF
// && in[ref + 2] == p2
// && (((in[ref] & 255) << 8) | (in[ref + 1] & 255)) ==
// ((future >> 8) & 0xffff)) {
if (ref < inPos
&& ref > 0
&& (off = (int)(inPos - ref - 1)) < MAX_OFF
&& in.get(ref + 2) == p2
&& in.get(ref + 1) == (byte) (future >> 8)
&& in.get(ref) == (byte) (future >> 16)) {
// match
long maxLen = inLen - inPos - 2;
if (maxLen > MAX_REF) {
maxLen = MAX_REF;
}
if (outPos + 3 + 1 >= outLen) {
int c = literals == 0 ? 1 : 0;
if (outPos - c + 3 + 1 >= outLen)
return 0;
}
if (literals == 0) {
// multiple back-references,
// so there is no literal run control byte
outPos--;
} else {
// set the control byte at the start of the literal run
// to store the number of literals
out.set(outPos - literals - 1, (byte) (literals - 1));
literals = 0;
}
int len = 3;
while (len < maxLen && in.get(ref + len) == in.get(inPos + len)) {
len++;
}
len -= 2;
if (len < 7) {
out.set(outPos++, (byte) ((off >> 8) + (len << 5)));
} else {
out.set(outPos++, (byte) ((off >> 8) + (7 << 5)));
out.set(outPos++, (byte) (len - 7));
}
out.set(outPos++, (byte) off);
// move one byte forward to allow for a literal run control byte
outPos++;
inPos += len;
// rebuild the future, and store the last bytes to the hashtable.
// Storing hashes of the last bytes in back-reference improves
// the compression ratio and only reduces speed slightly.
future = first(in, inPos);
future = next(future, in, inPos);
hashTab[hash(future)] = inPos++;
future = next(future, in, inPos);
hashTab[hash(future)] = inPos++;
} else {
// copy one byte from input to output as part of literal
if (outPos >= outLen) {
return 0;
}
out.set(outPos++, in.get(inPos++));
literals++;
// at the end of this literal chunk, write the length
// to the control byte and start a new chunk
if (literals == MAX_LITERAL) {
out.set(outPos - literals - 1, (byte) (literals - 1));
literals = 0;
// move ahead one byte to allow for the
// literal run control byte
outPos++;
}
}
}
if (outPos + 3 > outLen) {
return 0;
}
// write the remaining few bytes as literals
while (inPos < inLen) {
out.set(outPos++, in.get(inPos++));
literals++;
if (literals == MAX_LITERAL) {
out.set(outPos - literals - 1, (byte) (literals - 1));
literals = 0;
outPos++;
}
}
// writes the final literal run length to the control byte
out.set(outPos - literals - 1, (byte) (literals - 1));
if (literals == 0) {
outPos--;
}
return outPos;
} catch (ArrayIndexOutOfBoundsException e) {
return 0;
}
}
private static int first(ByteArray in, long inPos) {
return (in.get(inPos) << 8) | (in.get(inPos + 1) & 255);
}
private static int next(int v, ByteArray in, long inPos) {
return (v << 8) | (in.get(inPos + 2) & 255);
}
private static int hash(int h) {
return ((h * 2777) >> 9) & (HASH_SIZE - 1);
}
}
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