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55 lines
2.0 KiB
C
55 lines
2.0 KiB
C
/* 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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#endif /* BROTLI_COMMON_CONSTANTS_H_ */
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