c8841bc9de
Motivation: LZ4 compression codec provides sending and receiving data encoded by very fast LZ4 algorithm. Modifications: - Added `lz4` library which implements LZ4 algorithm. - Implemented Lz4FramedEncoder which extends MessageToByteEncoder and provides compression of outgoing messages. - Added tests to verify the Lz4FramedEncoder and how it can compress data for the next uncompression using the original library. - Implemented Lz4FramedDecoder which extends ByteToMessageDecoder and provides uncompression of incoming messages. - Added tests to verify the Lz4FramedDecoder and how it can uncompress data after compression using the original library. - Added integration tests for Lz4FramedEncoder/Decoder. Result: Full LZ4 compression codec which can compress/uncompress data using LZ4 algorithm.
73 lines
2.4 KiB
Java
73 lines
2.4 KiB
Java
/*
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* Copyright 2014 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.compression;
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final class Lz4Constants {
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/**
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* Magic number of LZ4 block.
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*/
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static final long MAGIC_NUMBER = (long) 'L' << 56 |
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(long) 'Z' << 48 |
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(long) '4' << 40 |
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(long) 'B' << 32 |
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'l' << 24 |
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'o' << 16 |
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'c' << 8 |
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'k';
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/**
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* Full length of LZ4 block header.
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*/
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static final int HEADER_LENGTH = 8 + // magic number
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1 + // token
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4 + // compressed length
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4 + // decompressed length
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4; // checksum
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/**
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* Offsets of header's parts.
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*/
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static final int TOKEN_OFFSET = 8;
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static final int COMPRESSED_LENGTH_OFFSET = TOKEN_OFFSET + 1;
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static final int DECOMPRESSED_LENGTH_OFFSET = COMPRESSED_LENGTH_OFFSET + 4;
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static final int CHECKSUM_OFFSET = DECOMPRESSED_LENGTH_OFFSET + 4;
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/**
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* Base value for compression level.
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*/
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static final int COMPRESSION_LEVEL_BASE = 10;
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/**
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* LZ4 block sizes.
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*/
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static final int MIN_BLOCK_SIZE = 64;
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static final int MAX_BLOCK_SIZE = 1 << COMPRESSION_LEVEL_BASE + 0x0F; // 32 M
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static final int DEFAULT_BLOCK_SIZE = 1 << 16; // 64 KB
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/**
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* LZ4 block types.
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*/
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static final int BLOCK_TYPE_NON_COMPRESSED = 0x10;
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static final int BLOCK_TYPE_COMPRESSED = 0x20;
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/**
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* Default seed value for xxhash.
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*/
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static final int DEFAULT_SEED = 0x9747b28c;
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private Lz4Constants() { }
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}
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