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Easy Redis Java client and Real-Time Data Platform. Valkey compatible. Sync/Async/RxJava3/Reactive API. Client side caching. Over 50 Redis based Java objects and services: JCache API, Apache Tomcat, Hibernate, Spring, Set, Multimap, SortedSet, Map, List, Queue, Deque, Semaphore, Lock, AtomicLong, Map Reduce, Bloom filter, Scheduler, RPC

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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 compressor.
 * 

* Instances of this class are thread-safe. */ public abstract class LZ4Compressor { /** * Returns the maximum compressed length for an input of size length. * * @param length the input size in bytes * @return the maximum compressed length in bytes */ @SuppressWarnings("static-method") public final int maxCompressedLength(int length) { return LZ4Utils.maxCompressedLength(length); } /** * Compresses src[srcOff:srcOff+srcLen] into * dest[destOff:destOff+maxDestLen] and returns the compressed * length. * * This method will throw a {@link LZ4Exception} if this compressor is unable * to compress the input into less than maxDestLen bytes. To * prevent this exception to be thrown, you should make sure that * maxDestLen >= maxCompressedLength(srcLen). * * @param src the source data * @param srcOff the start offset in src * @param srcLen the number of bytes to compress * @param dest the destination buffer * @param destOff the start offset in dest * @param maxDestLen the maximum number of bytes to write in dest * @throws LZ4Exception if maxDestLen is too small * @return the compressed size */ public abstract int compress(byte[] src, int srcOff, int srcLen, byte[] dest, int destOff, int maxDestLen); /** * Compresses src[srcOff:srcOff+srcLen] into * dest[destOff:destOff+maxDestLen] and returns the compressed * length. * * This method will throw a {@link LZ4Exception} if this compressor is unable * to compress the input into less than maxDestLen bytes. To * prevent this exception to be thrown, you should make sure that * maxDestLen >= maxCompressedLength(srcLen). * * {@link ByteBuffer} positions remain unchanged. * * @param src the source data * @param srcOff the start offset in src * @param srcLen the number of bytes to compress * @param dest the destination buffer * @param destOff the start offset in dest * @param maxDestLen the maximum number of bytes to write in dest * @throws LZ4Exception if maxDestLen is too small * @return the compressed size */ public abstract int compress(ByteBuffer src, int srcOff, int srcLen, ByteBuffer dest, int destOff, int maxDestLen); /** * Convenience method, equivalent to calling * {@link #compress(byte[], int, int, byte[], int, int) compress(src, srcOff, srcLen, dest, destOff, dest.length - destOff)}. * * @param src the source data * @param srcOff the start offset in src * @param srcLen the number of bytes to compress * @param dest the destination buffer * @param destOff the start offset in dest * @throws LZ4Exception if dest is too small * @return the compressed size */ public final int compress(byte[] src, int srcOff, int srcLen, byte[] dest, int destOff) { return compress(src, srcOff, srcLen, dest, destOff, dest.length - destOff); } /** * Convenience method, equivalent to calling * {@link #compress(byte[], int, int, byte[], int) compress(src, 0, src.length, dest, 0)}. * * @param src the source data * @param dest the destination buffer * @throws LZ4Exception if dest is too small * @return the compressed size */ public final int compress(byte[] src, byte[] dest) { return compress(src, 0, src.length, dest, 0); } /** * Convenience method which returns src[srcOff:srcOff+srcLen] * compressed. *

Warning: this method has an * important overhead due to the fact that it needs to allocate a buffer to * compress into, and then needs to resize this buffer to the actual * compressed length.

*

Here is how this method is implemented:

*
   * final int maxCompressedLength = maxCompressedLength(srcLen);
   * final byte[] compressed = new byte[maxCompressedLength];
   * final int compressedLength = compress(src, srcOff, srcLen, compressed, 0);
   * return Arrays.copyOf(compressed, compressedLength);
   * 
* * @param src the source data * @param srcOff the start offset in src * @param srcLen the number of bytes to compress * @return the compressed data */ public final byte[] compress(byte[] src, int srcOff, int srcLen) { final int maxCompressedLength = maxCompressedLength(srcLen); final byte[] compressed = new byte[maxCompressedLength]; final int compressedLength = compress(src, srcOff, srcLen, compressed, 0); return Arrays.copyOf(compressed, compressedLength); } /** * Convenience method, equivalent to calling * {@link #compress(byte[], int, int) compress(src, 0, src.length)}. * * @param src the source data * @return the compressed data */ public final byte[] compress(byte[] src) { return compress(src, 0, src.length); } /** * Compresses src into dest. Calling this method * will update the positions of both {@link ByteBuffer}s. * * @param src the source data * @param dest the destination buffer * @throws LZ4Exception if dest is too small */ public final void compress(ByteBuffer src, ByteBuffer dest) { final int cpLen = compress(src, src.position(), src.remaining(), dest, dest.position(), dest.remaining()); src.position(src.limit()); dest.position(dest.position() + cpLen); } @Override public String toString() { return getClass().getSimpleName(); } }




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