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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(); } }




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