--- /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.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;
+ }
+
+}
Code Review / simantics / platform.git / blobdiff