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Minimal LZ4 java only library
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// Auto-generated: DO NOT EDIT
package com.github.czietsman.lz4;
import com.github.czietsman.lz4.LZ4Utils.Match;
import com.github.czietsman.util.ByteBufferUtils;
import com.github.czietsman.util.Utils;
import java.nio.ByteBuffer;
import java.util.Arrays;
import static com.github.czietsman.lz4.LZ4Constants.*;
import static com.github.czietsman.lz4.LZ4Utils.copyTo;
import static com.github.czietsman.lz4.LZ4Utils.hashHC;
/**
* High compression compressor.
*/
final class LZ4HCJavaSafeCompressor extends LZ4Compressor {
public static final LZ4Compressor INSTANCE = new LZ4HCJavaSafeCompressor();
private final int maxAttempts;
final int compressionLevel;
LZ4HCJavaSafeCompressor() {
this(DEFAULT_COMPRESSION_LEVEL);
}
LZ4HCJavaSafeCompressor(int compressionLevel) {
this.maxAttempts = 1 << (compressionLevel - 1);
this.compressionLevel = compressionLevel;
}
private class HashTable {
static final int MASK = MAX_DISTANCE - 1;
int nextToUpdate;
private final int base;
private final int[] hashTable;
private final short[] chainTable;
HashTable(int base) {
this.base = base;
nextToUpdate = base;
hashTable = new int[HASH_TABLE_SIZE_HC];
Arrays.fill(hashTable, -1);
chainTable = new short[MAX_DISTANCE];
}
private int hashPointer(byte[] bytes, int off) {
final int v = Utils.readInt(bytes, off);
return hashPointer(v);
}
private int hashPointer(ByteBuffer bytes, int off) {
final int v = ByteBufferUtils.readInt(bytes, off);
return hashPointer(v);
}
private int hashPointer(int v) {
final int h = hashHC(v);
return hashTable[h];
}
private int next(int off) {
return off - (chainTable[off & MASK] & 0xFFFF);
}
private void addHash(byte[] bytes, int off) {
final int v = Utils.readInt(bytes, off);
addHash(v, off);
}
private void addHash(ByteBuffer bytes, int off) {
final int v = ByteBufferUtils.readInt(bytes, off);
addHash(v, off);
}
private void addHash(int v, int off) {
final int h = hashHC(v);
int delta = off - hashTable[h];
assert delta > 0 : delta;
if (delta >= MAX_DISTANCE) {
delta = MAX_DISTANCE - 1;
}
chainTable[off & MASK] = (short) delta;
hashTable[h] = off;
}
void insert(int off, byte[] bytes) {
for (; nextToUpdate < off; ++nextToUpdate) {
addHash(bytes, nextToUpdate);
}
}
void insert(int off, ByteBuffer bytes) {
for (; nextToUpdate < off; ++nextToUpdate) {
addHash(bytes, nextToUpdate);
}
}
boolean insertAndFindBestMatch(byte[] buf, int off, int matchLimit, Match match) {
match.start = off;
match.len = 0;
int delta = 0;
int repl = 0;
insert(off, buf);
int ref = hashPointer(buf, off);
if (ref >= off - 4 && ref <= off && ref >= base) { // potential repetition
if (LZ4SafeUtils.readIntEquals(buf, ref, off)) { // confirmed
delta = off - ref;
repl = match.len = MIN_MATCH + LZ4SafeUtils.commonBytes(buf, ref + MIN_MATCH, off + MIN_MATCH, matchLimit);
match.ref = ref;
}
ref = next(ref);
}
for (int i = 0; i < maxAttempts; ++i) {
if (ref < Math.max(base, off - MAX_DISTANCE + 1) || ref > off) {
break;
}
if (LZ4SafeUtils.readIntEquals(buf, ref, off)) {
final int matchLen = MIN_MATCH + LZ4SafeUtils.commonBytes(buf, ref + MIN_MATCH, off + MIN_MATCH, matchLimit);
if (matchLen > match.len) {
match.ref = ref;
match.len = matchLen;
}
}
ref = next(ref);
}
if (repl != 0) {
int ptr = off;
final int end = off + repl - (MIN_MATCH - 1);
while (ptr < end - delta) {
chainTable[ptr & MASK] = (short) delta; // pre load
++ptr;
}
do {
chainTable[ptr & MASK] = (short) delta;
hashTable[hashHC(Utils.readInt(buf, ptr))] = ptr;
++ptr;
} while (ptr < end);
nextToUpdate = end;
}
return match.len != 0;
}
boolean insertAndFindWiderMatch(byte[] buf, int off, int startLimit, int matchLimit, int minLen, Match match) {
match.len = minLen;
insert(off, buf);
final int delta = off - startLimit;
int ref = hashPointer(buf, off);
for (int i = 0; i < maxAttempts; ++i) {
if (ref < Math.max(base, off - MAX_DISTANCE + 1) || ref > off) {
break;
}
if (LZ4SafeUtils.readIntEquals(buf, ref, off)) {
final int matchLenForward = MIN_MATCH + LZ4SafeUtils.commonBytes(buf, ref + MIN_MATCH, off + MIN_MATCH, matchLimit);
final int matchLenBackward = LZ4SafeUtils.commonBytesBackward(buf, ref, off, base, startLimit);
final int matchLen = matchLenBackward + matchLenForward;
if (matchLen > match.len) {
match.len = matchLen;
match.ref = ref - matchLenBackward;
match.start = off - matchLenBackward;
}
}
ref = next(ref);
}
return match.len > minLen;
}
boolean insertAndFindBestMatch(ByteBuffer buf, int off, int matchLimit, Match match) {
match.start = off;
match.len = 0;
int delta = 0;
int repl = 0;
insert(off, buf);
int ref = hashPointer(buf, off);
if (ref >= off - 4 && ref <= off && ref >= base) { // potential repetition
if (LZ4ByteBufferUtils.readIntEquals(buf, ref, off)) { // confirmed
delta = off - ref;
repl = match.len = MIN_MATCH + LZ4ByteBufferUtils.commonBytes(buf, ref + MIN_MATCH, off + MIN_MATCH, matchLimit);
match.ref = ref;
}
ref = next(ref);
}
for (int i = 0; i < maxAttempts; ++i) {
if (ref < Math.max(base, off - MAX_DISTANCE + 1) || ref > off) {
break;
}
if (LZ4ByteBufferUtils.readIntEquals(buf, ref, off)) {
final int matchLen = MIN_MATCH + LZ4ByteBufferUtils.commonBytes(buf, ref + MIN_MATCH, off + MIN_MATCH, matchLimit);
if (matchLen > match.len) {
match.ref = ref;
match.len = matchLen;
}
}
ref = next(ref);
}
if (repl != 0) {
int ptr = off;
final int end = off + repl - (MIN_MATCH - 1);
while (ptr < end - delta) {
chainTable[ptr & MASK] = (short) delta; // pre load
++ptr;
}
do {
chainTable[ptr & MASK] = (short) delta;
hashTable[hashHC(ByteBufferUtils.readInt(buf, ptr))] = ptr;
++ptr;
} while (ptr < end);
nextToUpdate = end;
}
return match.len != 0;
}
boolean insertAndFindWiderMatch(ByteBuffer buf, int off, int startLimit, int matchLimit, int minLen, Match match) {
match.len = minLen;
insert(off, buf);
final int delta = off - startLimit;
int ref = hashPointer(buf, off);
for (int i = 0; i < maxAttempts; ++i) {
if (ref < Math.max(base, off - MAX_DISTANCE + 1) || ref > off) {
break;
}
if (LZ4ByteBufferUtils.readIntEquals(buf, ref, off)) {
final int matchLenForward = MIN_MATCH + LZ4ByteBufferUtils.commonBytes(buf, ref + MIN_MATCH, off + MIN_MATCH, matchLimit);
final int matchLenBackward = LZ4ByteBufferUtils.commonBytesBackward(buf, ref, off, base, startLimit);
final int matchLen = matchLenBackward + matchLenForward;
if (matchLen > match.len) {
match.len = matchLen;
match.ref = ref - matchLenBackward;
match.start = off - matchLenBackward;
}
}
ref = next(ref);
}
return match.len > minLen;
}
}
@Override
public int compress(byte[] src, int srcOff, int srcLen, byte[] dest, int destOff, int maxDestLen) {
Utils.checkRange(src, srcOff, srcLen);
Utils.checkRange(dest, destOff, maxDestLen);
final int srcEnd = srcOff + srcLen;
final int destEnd = destOff + maxDestLen;
final int mfLimit = srcEnd - MF_LIMIT;
final int matchLimit = srcEnd - LAST_LITERALS;
int sOff = srcOff;
int dOff = destOff;
int anchor = sOff++;
final HashTable ht = new HashTable(srcOff);
final Match match0 = new Match();
final Match match1 = new Match();
final Match match2 = new Match();
final Match match3 = new Match();
main:
while (sOff < mfLimit) {
if (!ht.insertAndFindBestMatch(src, sOff, matchLimit, match1)) {
++sOff;
continue;
}
// saved, in case we would skip too much
copyTo(match1, match0);
search2:
while (true) {
assert match1.start >= anchor;
if (match1.end() >= mfLimit
|| !ht.insertAndFindWiderMatch(src, match1.end() - 2, match1.start + 1, matchLimit, match1.len, match2)) {
// no better match
dOff = LZ4SafeUtils.encodeSequence(src, anchor, match1.start, match1.ref, match1.len, dest, dOff, destEnd);
anchor = sOff = match1.end();
continue main;
}
if (match0.start < match1.start) {
if (match2.start < match1.start + match0.len) { // empirical
copyTo(match0, match1);
}
}
assert match2.start > match1.start;
if (match2.start - match1.start < 3) { // First Match too small : removed
copyTo(match2, match1);
continue search2;
}
search3:
while (true) {
if (match2.start - match1.start < OPTIMAL_ML) {
int newMatchLen = match1.len;
if (newMatchLen > OPTIMAL_ML) {
newMatchLen = OPTIMAL_ML;
}
if (match1.start + newMatchLen > match2.end() - MIN_MATCH) {
newMatchLen = match2.start - match1.start + match2.len - MIN_MATCH;
}
final int correction = newMatchLen - (match2.start - match1.start);
if (correction > 0) {
match2.fix(correction);
}
}
if (match2.start + match2.len >= mfLimit
|| !ht.insertAndFindWiderMatch(src, match2.end() - 3, match2.start, matchLimit, match2.len, match3)) {
// no better match -> 2 sequences to encode
if (match2.start < match1.end()) {
match1.len = match2.start - match1.start;
}
// encode seq 1
dOff = LZ4SafeUtils.encodeSequence(src, anchor, match1.start, match1.ref, match1.len, dest, dOff, destEnd);
anchor = sOff = match1.end();
// encode seq 2
dOff = LZ4SafeUtils.encodeSequence(src, anchor, match2.start, match2.ref, match2.len, dest, dOff, destEnd);
anchor = sOff = match2.end();
continue main;
}
if (match3.start < match1.end() + 3) { // Not enough space for match 2 : remove it
if (match3.start >= match1.end()) { // // can write Seq1 immediately ==> Seq2 is removed, so Seq3 becomes Seq1
if (match2.start < match1.end()) {
final int correction = match1.end() - match2.start;
match2.fix(correction);
if (match2.len < MIN_MATCH) {
copyTo(match3, match2);
}
}
dOff = LZ4SafeUtils.encodeSequence(src, anchor, match1.start, match1.ref, match1.len, dest, dOff, destEnd);
anchor = sOff = match1.end();
copyTo(match3, match1);
copyTo(match2, match0);
continue search2;
}
copyTo(match3, match2);
continue search3;
}
// OK, now we have 3 ascending matches; let's write at least the first one
if (match2.start < match1.end()) {
if (match2.start - match1.start < ML_MASK) {
if (match1.len > OPTIMAL_ML) {
match1.len = OPTIMAL_ML;
}
if (match1.end() > match2.end() - MIN_MATCH) {
match1.len = match2.end() - match1.start - MIN_MATCH;
}
final int correction = match1.end() - match2.start;
match2.fix(correction);
} else {
match1.len = match2.start - match1.start;
}
}
dOff = LZ4SafeUtils.encodeSequence(src, anchor, match1.start, match1.ref, match1.len, dest, dOff, destEnd);
anchor = sOff = match1.end();
copyTo(match2, match1);
copyTo(match3, match2);
continue search3;
}
}
}
dOff = LZ4SafeUtils.lastLiterals(src, anchor, srcEnd - anchor, dest, dOff, destEnd);
return dOff - destOff;
}
@Override
public int compress(ByteBuffer src, int srcOff, int srcLen, ByteBuffer dest, int destOff, int maxDestLen) {
if (src.hasArray() && dest.hasArray()) {
return compress(src.array(), srcOff + src.arrayOffset(), srcLen, dest.array(), destOff + dest.arrayOffset(), maxDestLen);
}
src = ByteBufferUtils.inNativeByteOrder(src);
dest = ByteBufferUtils.inNativeByteOrder(dest);
ByteBufferUtils.checkRange(src, srcOff, srcLen);
ByteBufferUtils.checkRange(dest, destOff, maxDestLen);
final int srcEnd = srcOff + srcLen;
final int destEnd = destOff + maxDestLen;
final int mfLimit = srcEnd - MF_LIMIT;
final int matchLimit = srcEnd - LAST_LITERALS;
int sOff = srcOff;
int dOff = destOff;
int anchor = sOff++;
final HashTable ht = new HashTable(srcOff);
final Match match0 = new Match();
final Match match1 = new Match();
final Match match2 = new Match();
final Match match3 = new Match();
main:
while (sOff < mfLimit) {
if (!ht.insertAndFindBestMatch(src, sOff, matchLimit, match1)) {
++sOff;
continue;
}
// saved, in case we would skip too much
copyTo(match1, match0);
search2:
while (true) {
assert match1.start >= anchor;
if (match1.end() >= mfLimit
|| !ht.insertAndFindWiderMatch(src, match1.end() - 2, match1.start + 1, matchLimit, match1.len, match2)) {
// no better match
dOff = LZ4ByteBufferUtils.encodeSequence(src, anchor, match1.start, match1.ref, match1.len, dest, dOff, destEnd);
anchor = sOff = match1.end();
continue main;
}
if (match0.start < match1.start) {
if (match2.start < match1.start + match0.len) { // empirical
copyTo(match0, match1);
}
}
assert match2.start > match1.start;
if (match2.start - match1.start < 3) { // First Match too small : removed
copyTo(match2, match1);
continue search2;
}
search3:
while (true) {
if (match2.start - match1.start < OPTIMAL_ML) {
int newMatchLen = match1.len;
if (newMatchLen > OPTIMAL_ML) {
newMatchLen = OPTIMAL_ML;
}
if (match1.start + newMatchLen > match2.end() - MIN_MATCH) {
newMatchLen = match2.start - match1.start + match2.len - MIN_MATCH;
}
final int correction = newMatchLen - (match2.start - match1.start);
if (correction > 0) {
match2.fix(correction);
}
}
if (match2.start + match2.len >= mfLimit
|| !ht.insertAndFindWiderMatch(src, match2.end() - 3, match2.start, matchLimit, match2.len, match3)) {
// no better match -> 2 sequences to encode
if (match2.start < match1.end()) {
match1.len = match2.start - match1.start;
}
// encode seq 1
dOff = LZ4ByteBufferUtils.encodeSequence(src, anchor, match1.start, match1.ref, match1.len, dest, dOff, destEnd);
anchor = sOff = match1.end();
// encode seq 2
dOff = LZ4ByteBufferUtils.encodeSequence(src, anchor, match2.start, match2.ref, match2.len, dest, dOff, destEnd);
anchor = sOff = match2.end();
continue main;
}
if (match3.start < match1.end() + 3) { // Not enough space for match 2 : remove it
if (match3.start >= match1.end()) { // // can write Seq1 immediately ==> Seq2 is removed, so Seq3 becomes Seq1
if (match2.start < match1.end()) {
final int correction = match1.end() - match2.start;
match2.fix(correction);
if (match2.len < MIN_MATCH) {
copyTo(match3, match2);
}
}
dOff = LZ4ByteBufferUtils.encodeSequence(src, anchor, match1.start, match1.ref, match1.len, dest, dOff, destEnd);
anchor = sOff = match1.end();
copyTo(match3, match1);
copyTo(match2, match0);
continue search2;
}
copyTo(match3, match2);
continue search3;
}
// OK, now we have 3 ascending matches; let's write at least the first one
if (match2.start < match1.end()) {
if (match2.start - match1.start < ML_MASK) {
if (match1.len > OPTIMAL_ML) {
match1.len = OPTIMAL_ML;
}
if (match1.end() > match2.end() - MIN_MATCH) {
match1.len = match2.end() - match1.start - MIN_MATCH;
}
final int correction = match1.end() - match2.start;
match2.fix(correction);
} else {
match1.len = match2.start - match1.start;
}
}
dOff = LZ4ByteBufferUtils.encodeSequence(src, anchor, match1.start, match1.ref, match1.len, dest, dOff, destEnd);
anchor = sOff = match1.end();
copyTo(match2, match1);
copyTo(match3, match2);
continue search3;
}
}
}
dOff = LZ4ByteBufferUtils.lastLiterals(src, anchor, srcEnd - anchor, dest, dOff, destEnd);
return dOff - destOff;
}
}
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