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55 lines
2.1 KiB
55 lines
2.1 KiB
/* Copyright 2016 Google Inc. All Rights Reserved. |
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Distributed under MIT license. |
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See file LICENSE for detail or copy at https://opensource.org/licenses/MIT |
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*/ |
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#ifndef BROTLI_COMMON_CONSTANTS_H_ |
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#define BROTLI_COMMON_CONSTANTS_H_ |
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/* Specification: 7.3. Encoding of the context map */ |
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#define BROTLI_CONTEXT_MAP_MAX_RLE 16 |
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/* Specification: 2. Compressed representation overview */ |
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#define BROTLI_MAX_NUMBER_OF_BLOCK_TYPES 256 |
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/* Specification: 3.3. Alphabet sizes: insert-and-copy length */ |
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#define BROTLI_NUM_LITERAL_SYMBOLS 256 |
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#define BROTLI_NUM_COMMAND_SYMBOLS 704 |
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#define BROTLI_NUM_BLOCK_LEN_SYMBOLS 26 |
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#define BROTLI_MAX_CONTEXT_MAP_SYMBOLS (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + \ |
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BROTLI_CONTEXT_MAP_MAX_RLE) |
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#define BROTLI_MAX_BLOCK_TYPE_SYMBOLS (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + 2) |
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/* Specification: 3.5. Complex prefix codes */ |
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#define BROTLI_REPEAT_PREVIOUS_CODE_LENGTH 16 |
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#define BROTLI_REPEAT_ZERO_CODE_LENGTH 17 |
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#define BROTLI_CODE_LENGTH_CODES (BROTLI_REPEAT_ZERO_CODE_LENGTH + 1) |
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/* "code length of 8 is repeated" */ |
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#define BROTLI_INITIAL_REPEATED_CODE_LENGTH 8 |
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/* Specification: 4. Encoding of distances */ |
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#define BROTLI_NUM_DISTANCE_SHORT_CODES 16 |
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#define BROTLI_MAX_NPOSTFIX 3 |
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#define BROTLI_MAX_NDIRECT 120 |
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#define BROTLI_MAX_DISTANCE_BITS 24U |
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/* BROTLI_NUM_DISTANCE_SYMBOLS == 520 */ |
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#define BROTLI_NUM_DISTANCE_SYMBOLS (BROTLI_NUM_DISTANCE_SHORT_CODES + \ |
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BROTLI_MAX_NDIRECT + \ |
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(BROTLI_MAX_DISTANCE_BITS << \ |
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(BROTLI_MAX_NPOSTFIX + 1))) |
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/* 7.1. Context modes and context ID lookup for literals */ |
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/* "context IDs for literals are in the range of 0..63" */ |
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#define BROTLI_LITERAL_CONTEXT_BITS 6 |
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/* 7.2. Context ID for distances */ |
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#define BROTLI_DISTANCE_CONTEXT_BITS 2 |
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/* 9.1. Format of the Stream Header */ |
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/* Number of slack bytes for window size. Don't confuse |
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with BROTLI_NUM_DISTANCE_SHORT_CODES. */ |
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#define BROTLI_WINDOW_GAP 16 |
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#define BROTLI_MAX_BACKWARD_LIMIT(W) (((size_t)1 << (W)) - BROTLI_WINDOW_GAP) |
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#endif /* BROTLI_COMMON_CONSTANTS_H_ */
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