net.jpountz.lz4.LZ4FastDecompressor Maven / Gradle / Ivy
package net.jpountz.lz4;
import java.nio.ByteBuffer;
/*
* 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.
*/
/**
* LZ4 decompressor that requires the size of the original input to be known.
* Use {@link LZ4SafeDecompressor} if you only know the size of the
* compressed stream.
*
* From lz4-java 1.6.0, it is deprecated to use a JNI-binding instance
* of this class; i.e., an instasnce returned by
* {@link LZ4Factory#fastDecompressor()} of {@link LZ4Factory#nativeInstance()}.
* Please see {@link LZ4Factory#nativeInstance()} for details.
*
* Instances of this class are thread-safe.
*
* @see LZ4Factory#nativeInstance()
*/
public abstract class LZ4FastDecompressor implements LZ4Decompressor {
/** Decompresses src[srcOff:] into dest[destOff:destOff+destLen]
* and returns the number of bytes read from src.
* destLen must be exactly the size of the decompressed data.
*
* @param src the compressed data
* @param srcOff the start offset in src
* @param dest the destination buffer to store the decompressed data
* @param destOff the start offset in dest
* @param destLen the exact size of the original input
* @return the number of bytes read to restore the original input
*/
public abstract int decompress(byte[] src, int srcOff, byte[] dest, int destOff, int destLen);
/** Decompresses src[srcOff:] into dest[destOff:destOff+destLen]
* and returns the number of bytes read from src.
* destLen must be exactly the size of the decompressed data.
* The positions and limits of the {@link ByteBuffer}s remain unchanged.
*
* @param src the compressed data
* @param srcOff the start offset in src
* @param dest the destination buffer to store the decompressed data
* @param destOff the start offset in dest
* @param destLen the exact size of the original input
* @return the number of bytes read to restore the original input
*/
public abstract int decompress(ByteBuffer src, int srcOff, ByteBuffer dest, int destOff, int destLen);
/**
* Convenience method, equivalent to calling
* {@link #decompress(byte[], int, byte[], int, int) decompress(src, 0, dest, 0, destLen)}.
*
* @param src the compressed data
* @param dest the destination buffer to store the decompressed data
* @param destLen the exact size of the original input
* @return the number of bytes read to restore the original input
*/
public final int decompress(byte[] src, byte[] dest, int destLen) {
return decompress(src, 0, dest, 0, destLen);
}
/**
* Convenience method, equivalent to calling
* {@link #decompress(byte[], byte[], int) decompress(src, dest, dest.length)}.
*
* @param src the compressed data
* @param dest the destination buffer to store the decompressed data
* @return the number of bytes read to restore the original input
*/
public final int decompress(byte[] src, byte[] dest) {
return decompress(src, dest, dest.length);
}
/**
* Convenience method which returns src[srcOff:?]
* decompressed.
*
Warning: this method has an
* important overhead due to the fact that it needs to allocate a buffer to
* decompress into.
* Here is how this method is implemented:
*
* final byte[] decompressed = new byte[destLen];
* decompress(src, srcOff, decompressed, 0, destLen);
* return decompressed;
*
*
* @param src the compressed data
* @param srcOff the start offset in src
* @param destLen the exact size of the original input
* @return the decompressed data
*/
public final byte[] decompress(byte[] src, int srcOff, int destLen) {
final byte[] decompressed = new byte[destLen];
decompress(src, srcOff, decompressed, 0, destLen);
return decompressed;
}
/**
* Convenience method, equivalent to calling
* {@link #decompress(byte[], int, int) decompress(src, 0, destLen)}.
*
* @param src the compressed data
* @param destLen the exact size of the original input
* @return the decompressed data
*/
public final byte[] decompress(byte[] src, int destLen) {
return decompress(src, 0, destLen);
}
/**
* Decompresses src into dest. dest's
* {@link ByteBuffer#remaining()} must be exactly the size of the decompressed
* data. This method moves the positions of the buffers.
*
* @param src the compressed data
* @param dest the destination buffer to store the decompressed data
*/
public final void decompress(ByteBuffer src, ByteBuffer dest) {
final int read = decompress(src, src.position(), dest, dest.position(), dest.remaining());
dest.position(dest.limit());
src.position(src.position() + read);
}
@Override
public String toString() {
return getClass().getSimpleName();
}
}