Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.lz4 / src / net / jpountz / lz4 / LZ4SafeDecompressor.java

diff --git a/bundles/org.simantics.lz4/src/net/jpountz/lz4/LZ4SafeDecompressor.java b/bundles/org.simantics.lz4/src/net/jpountz/lz4/LZ4SafeDecompressor.java
new file mode 100644 (file)
index 0000000..2416ccb
--- /dev/null
+++ b/bundles/org.simantics.lz4/src/net/jpountz/lz4/LZ4SafeDecompressor.java
@@ -0,0 +1,117 @@
+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 java.nio.ByteBuffer;
+import java.util.Arrays;
+
+/**
+ * LZ4 decompressor that requires the size of the compressed data to be known.
+ * <p>
+ * Implementations of this class are usually a little slower than those of
+ * {@link LZ4FastDecompressor} but do not require the size of the original data to
+ * be known.
+ */
+public abstract class LZ4SafeDecompressor implements LZ4UnknownSizeDecompressor {
+
+  /**
+   * Decompress <code>src[srcOff:srcLen]</code> into
+   * <code>dest[destOff:destOff+maxDestLen]</code> and returns the number of
+   * decompressed bytes written into <code>dest</code>.
+   *
+   * @param srcLen the exact size of the compressed stream
+   * @return the original input size
+   * @throws LZ4Exception if maxDestLen is too small
+   */
+  public abstract int decompress(byte[] src, int srcOff, int srcLen, byte[] dest, int destOff, int maxDestLen);
+
+  /**
+   * Uncompress <code>src[srcOff:srcLen]</code> into
+   * <code>dest[destOff:destOff+maxDestLen]</code> and returns the number of
+   * decompressed bytes written into <code>dest</code>.
+   *
+   * @param srcLen the exact size of the compressed stream
+   * @return the original input size
+   * @throws LZ4Exception if maxDestLen is too small
+   */
+  public abstract int decompress(ByteBuffer src, int srcOff, int srcLen, ByteBuffer dest, int destOff, int maxDestLen);
+
+  /**
+   * Convenience method, equivalent to calling
+   * {@link #decompress(byte[], int, int, byte[], int, int) decompress(src, srcOff, srcLen, dest, destOff, dest.length - destOff)}.
+   */
+  public final int decompress(byte[] src, int srcOff, int srcLen, byte[] dest, int destOff) {
+    return decompress(src, srcOff, srcLen, dest, destOff, dest.length - destOff);
+  }
+
+  /**
+   * Convenience method, equivalent to calling
+   * {@link #decompress(byte[], int, int, byte[], int) decompress(src, 0, src.length, dest, 0)}
+   */
+  public final int decompress(byte[] src, byte[] dest) {
+    return decompress(src, 0, src.length, dest, 0);
+  }
+
+  /**
+   * Convenience method which returns <code>src[srcOff:srcOff+srcLen]</code>
+   * decompressed.
+   * <p><b><span style="color:red">Warning</span></b>: this method has an
+   * important overhead due to the fact that it needs to allocate a buffer to
+   * decompress into, and then needs to resize this buffer to the actual
+   * decompressed length.</p>
+   * <p>Here is how this method is implemented:</p>
+   * <pre>
+   * byte[] decompressed = new byte[maxDestLen];
+   * final int decompressedLength = decompress(src, srcOff, srcLen, decompressed, 0, maxDestLen);
+   * if (decompressedLength != decompressed.length) {
+   *   decompressed = Arrays.copyOf(decompressed, decompressedLength);
+   * }
+   * return decompressed;
+   * </pre>
+   */
+  public final byte[] decompress(byte[] src, int srcOff, int srcLen, int maxDestLen) {
+    byte[] decompressed = new byte[maxDestLen];
+    final int decompressedLength = decompress(src, srcOff, srcLen, decompressed, 0, maxDestLen);
+    if (decompressedLength != decompressed.length) {
+      decompressed = Arrays.copyOf(decompressed, decompressedLength);
+    }
+    return decompressed;
+  }
+
+  /**
+   * Convenience method, equivalent to calling
+   * {@link #decompress(byte[], int, int, int) decompress(src, 0, src.length, maxDestLen)}.
+   */
+  public final byte[] decompress(byte[] src, int maxDestLen) {
+    return decompress(src, 0, src.length, maxDestLen);
+  }
+
+  /**
+   * Decompress <code>src</code> into <code>dest</code>. <code>src</code>'s
+   * {@link ByteBuffer#remaining()} must be exactly the size of the compressed
+   * data. This method moves the positions of the buffers.
+   */
+  public final void decompress(ByteBuffer src, ByteBuffer dest) {
+    final int decompressed = decompress(src, src.position(), src.remaining(), dest, dest.position(), dest.remaining());
+    src.position(src.limit());
+    dest.position(dest.position() + decompressed);
+  }
+
+  @Override
+  public String toString() {
+    return getClass().getSimpleName();
+  }
+
+}