/*
* Copyright 2014 The Netty Project
*
* The Netty Project licenses this file to you 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.
*/
package io.netty.handler.codec.compression;
final class Lz4Constants {
/**
* Magic number of LZ4 block.
*/
static final long MAGIC_NUMBER = (long) 'L' << 56 |
(long) 'Z' << 48 |
(long) '4' << 40 |
(long) 'B' << 32 |
'l' << 24 |
'o' << 16 |
'c' << 8 |
'k';
/**
* Full length of LZ4 block header.
*/
static final int HEADER_LENGTH = 8 + // magic number
1 + // token
4 + // compressed length
4 + // decompressed length
4; // checksum
/**
* Offsets of header's parts.
*/
static final int TOKEN_OFFSET = 8;
static final int COMPRESSED_LENGTH_OFFSET = TOKEN_OFFSET + 1;
static final int DECOMPRESSED_LENGTH_OFFSET = COMPRESSED_LENGTH_OFFSET + 4;
static final int CHECKSUM_OFFSET = DECOMPRESSED_LENGTH_OFFSET + 4;
/**
* Base value for compression level.
*/
static final int COMPRESSION_LEVEL_BASE = 10;
/**
* LZ4 block sizes.
*/
static final int MIN_BLOCK_SIZE = 64;
static final int MAX_BLOCK_SIZE = 1 << COMPRESSION_LEVEL_BASE + 0x0F; // 32 M
static final int DEFAULT_BLOCK_SIZE = 1 << 16; // 64 KB
/**
* LZ4 block types.
*/
static final int BLOCK_TYPE_NON_COMPRESSED = 0x10;
static final int BLOCK_TYPE_COMPRESSED = 0x20;
/**
* Default seed value for xxhash.
*/
static final int DEFAULT_SEED = 0x9747b28c;
private Lz4Constants() { }
}