net.jpountz.lz4.LZ4SafeDecompressor Maven / Gradle / Ivy
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package net.jpountz.lz4;
/*
* Copyright 2020 Adrien Grand and the lz4-java contributors.
*
* 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.
*
* 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 {
/**
* Decompresses src[srcOff:srcOff+srcLen] into
* dest[destOff:destOff+maxDestLen] and returns the number of
* decompressed bytes written into dest.
*
* @param src the compressed data
* @param srcOff the start offset in src
* @param srcLen the exact size of the compressed data
* @param dest the destination buffer to store the decompressed data
* @param destOff the start offset in dest
* @param maxDestLen the maximum number of bytes to write in dest
* @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);
/**
* Decompresses src[srcOff:srcOff+srcLen] into
* dest[destOff:destOff+maxDestLen] and returns the number of
* decompressed bytes written into dest.
* The positions and limits of the {@link ByteBuffer}s remain unchanged.
*
* @param src the compressed data
* @param srcOff the start offset in src
* @param srcLen the exact size of the compressed data
* @param dest the destination buffer to store the decompressed data
* @param destOff the start offset in dest
* @param maxDestLen the maximum number of bytes to write in dest
* @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)}.
*
* @param src the compressed data
* @param srcOff the start offset in src
* @param srcLen the exact size of the compressed data
* @param dest the destination buffer to store the decompressed data
* @param destOff the start offset in dest
* @return the original input size
* @throws LZ4Exception if dest is too small
*/
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)}
*
* @param src the compressed data
* @param dest the destination buffer to store the decompressed data
* @return the original input size
* @throws LZ4Exception if dest is too small
*/
public final int decompress(byte[] src, byte[] dest) {
return decompress(src, 0, src.length, dest, 0);
}
/**
* Convenience method which returns src[srcOff:srcOff+srcLen]
* decompressed.
*
Warning: 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.
* Here is how this method is implemented:
*
* 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;
*
*
* @param src the compressed data
* @param srcOff the start offset in src
* @param srcLen the exact size of the compressed data
* @param maxDestLen the maximum number of bytes to write in dest
* @return the decompressed data
* @throws LZ4Exception if maxDestLen is too small
*/
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)}.
*
* @param src the compressed data
* @param maxDestLen the maximum number of bytes to write in dest
* @return the decompressed data
* @throws LZ4Exception if maxDestLen is too small
*/
public final byte[] decompress(byte[] src, int maxDestLen) {
return decompress(src, 0, src.length, maxDestLen);
}
/**
* Decompresses src into dest. src's
* {@link ByteBuffer#remaining()} must be exactly the size of the compressed
* data. This method moves the positions of the buffers.
* @param src the compressed data
* @param dest the destination buffer to store the decompressed data
* @throws LZ4Exception if dest is too small
*/
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();
}
}