Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.lz4 / src / net / jpountz / lz4 / LZ4SafeUtils.java

diff --git a/bundles/org.simantics.lz4/src/net/jpountz/lz4/LZ4SafeUtils.java b/bundles/org.simantics.lz4/src/net/jpountz/lz4/LZ4SafeUtils.java
new file mode 100644 (file)
index 0000000..7842bd7
--- /dev/null
+++ b/bundles/org.simantics.lz4/src/net/jpountz/lz4/LZ4SafeUtils.java
@@ -0,0 +1,179 @@
+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.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 net.jpountz.util.SafeUtils;
+
+enum LZ4SafeUtils {
+  ;
+
+  static int hash(byte[] buf, int i) {
+    return LZ4Utils.hash(SafeUtils.readInt(buf, i));
+  }
+
+  static int hash64k(byte[] buf, int i) {
+    return LZ4Utils.hash64k(SafeUtils.readInt(buf, i));
+  }
+
+  static boolean readIntEquals(byte[] buf, int i, int j) {
+    return buf[i] == buf[j] && buf[i+1] == buf[j+1] && buf[i+2] == buf[j+2] && buf[i+3] == buf[j+3];
+  }
+
+  static void safeIncrementalCopy(byte[] dest, int matchOff, int dOff, int matchLen) {
+    for (int i = 0; i < matchLen; ++i) {
+      dest[dOff + i] = dest[matchOff + i];
+    }
+  }
+
+  static void wildIncrementalCopy(byte[] dest, int matchOff, int dOff, int matchCopyEnd) {
+    do {
+      copy8Bytes(dest, matchOff, dest, dOff);
+      matchOff += 8;
+      dOff += 8;
+    } while (dOff < matchCopyEnd);
+  }
+
+  static void copy8Bytes(byte[] src, int sOff, byte[] dest, int dOff) {
+    for (int i = 0; i < 8; ++i) {
+      dest[dOff + i] = src[sOff + i];
+    }
+  }
+
+  static int commonBytes(byte[] b, int o1, int o2, int limit) {
+    int count = 0;
+    while (o2 < limit && b[o1++] == b[o2++]) {
+      ++count;
+    }
+    return count;
+  }
+
+  static int commonBytesBackward(byte[] b, int o1, int o2, int l1, int l2) {
+    int count = 0;
+    while (o1 > l1 && o2 > l2 && b[--o1] == b[--o2]) {
+      ++count;
+    }
+    return count;
+  }
+
+  static void safeArraycopy(byte[] src, int sOff, byte[] dest, int dOff, int len) {
+    System.arraycopy(src, sOff, dest, dOff, len);
+  }
+
+  static void wildArraycopy(byte[] src, int sOff, byte[] dest, int dOff, int len) {
+    try {
+      for (int i = 0; i < len; i += 8) {
+        copy8Bytes(src, sOff + i, dest, dOff + i);
+      }
+    } catch (ArrayIndexOutOfBoundsException e) {
+      throw new LZ4Exception("Malformed input at offset " + sOff);
+    }
+  }
+
+  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++;
+
+    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[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 lastLiterals(byte[] src, int sOff, int srcLen, byte[] 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[dOff++] = (byte) (RUN_MASK << ML_BITS);
+      dOff = writeLen(runLen - RUN_MASK, dest, dOff);
+    } else {
+      dest[dOff++] = (byte) (runLen << ML_BITS);
+    }
+    // copy literals
+    System.arraycopy(src, sOff, dest, dOff, runLen);
+    dOff += runLen;
+
+    return dOff;
+  }
+
+  static int writeLen(int len, byte[] dest, int dOff) {
+    while (len >= 0xFF) {
+      dest[dOff++] = (byte) 0xFF;
+      len -= 0xFF;
+    }
+    dest[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;
+  }
+
+}