--- /dev/null
+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.UnsafeUtils.readByte;
+import static net.jpountz.util.UnsafeUtils.readInt;
+import static net.jpountz.util.UnsafeUtils.readLong;
+import static net.jpountz.util.UnsafeUtils.readShort;
+import static net.jpountz.util.UnsafeUtils.writeByte;
+import static net.jpountz.util.UnsafeUtils.writeInt;
+import static net.jpountz.util.UnsafeUtils.writeLong;
+import static net.jpountz.util.UnsafeUtils.writeShort;
+import static net.jpountz.util.Utils.NATIVE_BYTE_ORDER;
+
+import java.nio.ByteOrder;
+
+enum LZ4UnsafeUtils {
+ ;
+
+ static void safeArraycopy(byte[] src, int srcOff, byte[] dest, int destOff, int len) {
+ final int fastLen = len & 0xFFFFFFF8;
+ wildArraycopy(src, srcOff, dest, destOff, fastLen);
+ for (int i = 0, slowLen = len & 0x7; i < slowLen; i += 1) {
+ writeByte(dest, destOff + fastLen + i, readByte(src, srcOff + fastLen + i));
+ }
+ }
+
+ static void wildArraycopy(byte[] src, int srcOff, byte[] dest, int destOff, int len) {
+ for (int i = 0; i < len; i += 8) {
+ writeLong(dest, destOff + i, readLong(src, srcOff + i));
+ }
+ }
+
+ static void wildIncrementalCopy(byte[] 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 void safeIncrementalCopy(byte[] dest, int matchOff, int dOff, int matchLen) {
+ for (int i = 0; i < matchLen; ++i) {
+ dest[dOff + i] = dest[matchOff + i];
+ writeByte(dest, dOff + i, readByte(dest, matchOff + i));
+ }
+ }
+
+ static int readShortLittleEndian(byte[] src, int srcOff) {
+ short s = readShort(src, srcOff);
+ if (NATIVE_BYTE_ORDER == ByteOrder.BIG_ENDIAN) {
+ s = Short.reverseBytes(s);
+ }
+ return s & 0xFFFF;
+ }
+
+ static void writeShortLittleEndian(byte[] dest, int destOff, int value) {
+ short s = (short) value;
+ if (NATIVE_BYTE_ORDER == ByteOrder.BIG_ENDIAN) {
+ s = Short.reverseBytes(s);
+ }
+ writeShort(dest, destOff, s);
+ }
+
+ static boolean readIntEquals(byte[] src, int ref, int sOff) {
+ return readInt(src, ref) == readInt(src, sOff);
+ }
+
+ static int commonBytes(byte[] 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 (NATIVE_BYTE_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 writeLen(int len, byte[] dest, int dOff) {
+ while (len >= 0xFF) {
+ writeByte(dest, dOff++, 0xFF);
+ len -= 0xFF;
+ }
+ writeByte(dest, dOff++, len);
+ return dOff;
+ }
+
+ static int encodeSequence(byte[] src, int anchor, int matchOff, int matchRef, int matchLen, byte[] dest, int dOff, int destEnd) {
+ final int runLen = matchOff - anchor;
+ final int tokenOff = dOff++;
+ 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[dOff++] = (byte) matchDec;
+ dest[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[tokenOff] = (byte) token;
+
+ return dOff;
+ }
+
+ static int commonBytesBackward(byte[] b, int o1, int o2, int l1, int l2) {
+ int count = 0;
+ while (o1 > l1 && o2 > l2 && readByte(b, --o1) == readByte(b, --o2)) {
+ ++count;
+ }
+ return count;
+ }
+
+ static int lastLiterals(byte[] src, int sOff, int srcLen, byte[] dest, int dOff, int destEnd) {
+ return LZ4SafeUtils.lastLiterals(src, sOff, srcLen, dest, dOff, destEnd);
+ }
+
+}
Code Review / simantics / platform.git / blobdiff