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net.jpountz.lz4.LZ4ByteBufferUtils Maven / Gradle / Ivy
package net.jpountz.lz4;
/*
* 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.
*/
import static net.jpountz.lz4.LZ4Constants.COPY_LENGTH;
import static net.jpountz.lz4.LZ4Constants.LAST_LITERALS;
import static net.jpountz.lz4.LZ4Constants.ML_BITS;
import static net.jpountz.lz4.LZ4Constants.ML_MASK;
import static net.jpountz.lz4.LZ4Constants.RUN_MASK;
import static net.jpountz.util.ByteBufferUtils.readByte;
import static net.jpountz.util.ByteBufferUtils.readInt;
import static net.jpountz.util.ByteBufferUtils.readLong;
import static net.jpountz.util.ByteBufferUtils.writeByte;
import static net.jpountz.util.ByteBufferUtils.writeInt;
import static net.jpountz.util.ByteBufferUtils.writeLong;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
enum LZ4ByteBufferUtils {
;
static int hash(ByteBuffer buf, int i) {
return LZ4Utils.hash(readInt(buf, i));
}
static int hash64k(ByteBuffer buf, int i) {
return LZ4Utils.hash64k(readInt(buf, i));
}
static boolean readIntEquals(ByteBuffer buf, int i, int j) {
return buf.getInt(i) == buf.getInt(j);
}
static void safeIncrementalCopy(ByteBuffer dest, int matchOff, int dOff, int matchLen) {
for (int i = 0; i < matchLen; ++i) {
dest.put(dOff + i, dest.get(matchOff + i));
}
}
static void wildIncrementalCopy(ByteBuffer dest, int matchOff, int dOff, int matchCopyEnd) {
if (dOff - matchOff < 4) {
for (int i = 0; i < 4; ++i) {
writeByte(dest, dOff+i, readByte(dest, matchOff+i));
}
dOff += 4;
matchOff += 4;
int dec = 0;
assert dOff >= matchOff && dOff - matchOff < 8;
switch (dOff - matchOff) {
case 1:
matchOff -= 3;
break;
case 2:
matchOff -= 2;
break;
case 3:
matchOff -= 3;
dec = -1;
break;
case 5:
dec = 1;
break;
case 6:
dec = 2;
break;
case 7:
dec = 3;
break;
default:
break;
}
writeInt(dest, dOff, readInt(dest, matchOff));
dOff += 4;
matchOff -= dec;
} else if (dOff - matchOff < COPY_LENGTH) {
writeLong(dest, dOff, readLong(dest, matchOff));
dOff += dOff - matchOff;
}
while (dOff < matchCopyEnd) {
writeLong(dest, dOff, readLong(dest, matchOff));
dOff += 8;
matchOff += 8;
}
}
static int commonBytes(ByteBuffer src, int ref, int sOff, int srcLimit) {
int matchLen = 0;
while (sOff <= srcLimit - 8) {
if (readLong(src, sOff) == readLong(src, ref)) {
matchLen += 8;
ref += 8;
sOff += 8;
} else {
final int zeroBits;
if (src.order() == ByteOrder.BIG_ENDIAN) {
zeroBits = Long.numberOfLeadingZeros(readLong(src, sOff) ^ readLong(src, ref));
} else {
zeroBits = Long.numberOfTrailingZeros(readLong(src, sOff) ^ readLong(src, ref));
}
return matchLen + (zeroBits >>> 3);
}
}
while (sOff < srcLimit && readByte(src, ref++) == readByte(src, sOff++)) {
++matchLen;
}
return matchLen;
}
static int commonBytesBackward(ByteBuffer b, int o1, int o2, int l1, int l2) {
int count = 0;
while (o1 > l1 && o2 > l2 && b.get(--o1) == b.get(--o2)) {
++count;
}
return count;
}
static void safeArraycopy(ByteBuffer src, int sOff, ByteBuffer dest, int dOff, int len) {
for (int i = 0; i < len; ++i) {
dest.put(dOff + i, src.get(sOff + i));
}
}
static void wildArraycopy(ByteBuffer src, int sOff, ByteBuffer dest, int dOff, int len) {
assert src.order().equals(dest.order());
try {
for (int i = 0; i < len; i += 8) {
dest.putLong(dOff + i, src.getLong(sOff + i));
}
} catch (IndexOutOfBoundsException e) {
throw new LZ4Exception("Malformed input at offset " + sOff);
}
}
static int encodeSequence(ByteBuffer src, int anchor, int matchOff, int matchRef, int matchLen, ByteBuffer dest, int dOff, int destEnd) {
final int runLen = matchOff - anchor;
final int tokenOff = dOff++;
if (dOff + runLen + (2 + 1 + LAST_LITERALS) + (runLen >>> 8) > destEnd) {
throw new LZ4Exception("maxDestLen is too small");
}
int token;
if (runLen >= RUN_MASK) {
token = (byte) (RUN_MASK << ML_BITS);
dOff = writeLen(runLen - RUN_MASK, dest, dOff);
} else {
token = runLen << ML_BITS;
}
// copy literals
wildArraycopy(src, anchor, dest, dOff, runLen);
dOff += runLen;
// encode offset
final int matchDec = matchOff - matchRef;
dest.put(dOff++, (byte) matchDec);
dest.put(dOff++, (byte) (matchDec >>> 8));
// encode match len
matchLen -= 4;
if (dOff + (1 + LAST_LITERALS) + (matchLen >>> 8) > destEnd) {
throw new LZ4Exception("maxDestLen is too small");
}
if (matchLen >= ML_MASK) {
token |= ML_MASK;
dOff = writeLen(matchLen - RUN_MASK, dest, dOff);
} else {
token |= matchLen;
}
dest.put(tokenOff, (byte) token);
return dOff;
}
static int lastLiterals(ByteBuffer src, int sOff, int srcLen, ByteBuffer dest, int dOff, int destEnd) {
final int runLen = srcLen;
if (dOff + runLen + 1 + (runLen + 255 - RUN_MASK) / 255 > destEnd) {
throw new LZ4Exception();
}
if (runLen >= RUN_MASK) {
dest.put(dOff++, (byte) (RUN_MASK << ML_BITS));
dOff = writeLen(runLen - RUN_MASK, dest, dOff);
} else {
dest.put(dOff++, (byte) (runLen << ML_BITS));
}
// copy literals
safeArraycopy(src, sOff, dest, dOff, runLen);
dOff += runLen;
return dOff;
}
static int writeLen(int len, ByteBuffer dest, int dOff) {
while (len >= 0xFF) {
dest.put(dOff++, (byte) 0xFF);
len -= 0xFF;
}
dest.put(dOff++, (byte) len);
return dOff;
}
static class Match {
int start, ref, len;
void fix(int correction) {
start += correction;
ref += correction;
len -= correction;
}
int end() {
return start + len;
}
}
static void copyTo(Match m1, Match m2) {
m2.len = m1.len;
m2.start = m1.start;
m2.ref = m1.ref;
}
}
