/* Partial import of https://github.com/jpountz/lz4-java, Apache 2.0 licensed. */
package info.ata4.util.lz4;
import static info.ata4.util.lz4.LZ4Constants.*;
import java.nio.ByteBuffer;
import info.ata4.util.lz4.ByteBufferUtils;
import info.ata4.util.lz4.SafeUtils;
/**
* Decompressor.
*/
public final class LZ4JavaSafeFastDecompressor extends LZ4FastDecompressor {
public static final LZ4FastDecompressor INSTANCE = new LZ4JavaSafeFastDecompressor();
@Override
public int decompress(byte[] src, final int srcOff, byte[] dest, final int destOff, int destLen) {
SafeUtils.checkRange(src, srcOff);
SafeUtils.checkRange(dest, destOff, destLen);
if (destLen == 0) {
if (SafeUtils.readByte(src, srcOff) != 0) {
throw new LZ4Exception("Malformed input at " + srcOff);
}
return 1;
}
final int destEnd = destOff + destLen;
int sOff = srcOff;
int dOff = destOff;
while (true) {
final int token = SafeUtils.readByte(src, sOff) & 0xFF;
++sOff;
// literals
int literalLen = token >>> ML_BITS;
if (literalLen == RUN_MASK) {
byte len = (byte) 0xFF;
while ((len = SafeUtils.readByte(src, sOff++)) == (byte) 0xFF) {
literalLen += 0xFF;
}
literalLen += len & 0xFF;
}
final int literalCopyEnd = dOff + literalLen;
if (literalCopyEnd > destEnd - COPY_LENGTH) {
if (literalCopyEnd != destEnd) {
throw new LZ4Exception("Malformed input at " + sOff);
} else {
LZ4SafeUtils.safeArraycopy(src, sOff, dest, dOff, literalLen);
sOff += literalLen;
dOff = literalCopyEnd;
break; // EOF
}
}
LZ4SafeUtils.wildArraycopy(src, sOff, dest, dOff, literalLen);
sOff += literalLen;
dOff = literalCopyEnd;
// matchs
final int matchDec = SafeUtils.readShortLE(src, sOff);
sOff += 2;
int matchOff = dOff - matchDec;
if (matchOff < destOff) {
throw new LZ4Exception("Malformed input at " + sOff);
}
int matchLen = token & ML_MASK;
if (matchLen == ML_MASK) {
byte len = (byte) 0xFF;
while ((len = SafeUtils.readByte(src, sOff++)) == (byte) 0xFF) {
matchLen += 0xFF;
}
matchLen += len & 0xFF;
}
matchLen += MIN_MATCH;
final int matchCopyEnd = dOff + matchLen;
if (matchCopyEnd > destEnd - COPY_LENGTH) {
if (matchCopyEnd > destEnd) {
throw new LZ4Exception("Malformed input at " + sOff);
}
LZ4SafeUtils.safeIncrementalCopy(dest, matchOff, dOff, matchLen);
} else {
LZ4SafeUtils.wildIncrementalCopy(dest, matchOff, dOff, matchCopyEnd);
}
dOff = matchCopyEnd;
}
return sOff - srcOff;
}
@Override
public int decompress(ByteBuffer src, final int srcOff, ByteBuffer dest, final int destOff, int destLen) {
if (src.hasArray() && dest.hasArray()) {
return decompress(src.array(), srcOff + src.arrayOffset(), dest.array(), destOff + dest.arrayOffset(), destLen);
}
src = ByteBufferUtils.inNativeByteOrder(src);
dest = ByteBufferUtils.inNativeByteOrder(dest);
ByteBufferUtils.checkRange(src, srcOff);
ByteBufferUtils.checkRange(dest, destOff, destLen);
if (destLen == 0) {
if (ByteBufferUtils.readByte(src, srcOff) != 0) {
throw new LZ4Exception("Malformed input at " + srcOff);
}
return 1;
}
final int destEnd = destOff + destLen;
int sOff = srcOff;
int dOff = destOff;
while (true) {
final int token = ByteBufferUtils.readByte(src, sOff) & 0xFF;
++sOff;
// literals
int literalLen = token >>> ML_BITS;
if (literalLen == RUN_MASK) {
byte len = (byte) 0xFF;
while ((len = ByteBufferUtils.readByte(src, sOff++)) == (byte) 0xFF) {
literalLen += 0xFF;
}
literalLen += len & 0xFF;
}
final int literalCopyEnd = dOff + literalLen;
if (literalCopyEnd > destEnd - COPY_LENGTH) {
if (literalCopyEnd != destEnd) {
throw new LZ4Exception("Malformed input at " + sOff);
} else {
LZ4ByteBufferUtils.safeArraycopy(src, sOff, dest, dOff, literalLen);
sOff += literalLen;
dOff = literalCopyEnd;
break; // EOF
}
}
LZ4ByteBufferUtils.wildArraycopy(src, sOff, dest, dOff, literalLen);
sOff += literalLen;
dOff = literalCopyEnd;
// matchs
final int matchDec = ByteBufferUtils.readShortLE(src, sOff);
sOff += 2;
int matchOff = dOff - matchDec;
if (matchOff < destOff) {
throw new LZ4Exception("Malformed input at " + sOff);
}
int matchLen = token & ML_MASK;
if (matchLen == ML_MASK) {
byte len = (byte) 0xFF;
while ((len = ByteBufferUtils.readByte(src, sOff++)) == (byte) 0xFF) {
matchLen += 0xFF;
}
matchLen += len & 0xFF;
}
matchLen += MIN_MATCH;
final int matchCopyEnd = dOff + matchLen;
if (matchCopyEnd > destEnd - COPY_LENGTH) {
if (matchCopyEnd > destEnd) {
throw new LZ4Exception("Malformed input at " + sOff);
}
LZ4ByteBufferUtils.safeIncrementalCopy(dest, matchOff, dOff, matchLen);
} else {
LZ4ByteBufferUtils.wildIncrementalCopy(dest, matchOff, dOff, matchCopyEnd);
}
dOff = matchCopyEnd;
}
return sOff - srcOff;
}
}