78 lines
2.2 KiB
Go
78 lines
2.2 KiB
Go
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package brotli
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/* 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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/* Specification: 7.3. Encoding of the context map */
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const BROTLI_CONTEXT_MAP_MAX_RLE = 16
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/* Specification: 2. Compressed representation overview */
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const BROTLI_MAX_NUMBER_OF_BLOCK_TYPES = 256
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/* Specification: 3.3. Alphabet sizes: insert-and-copy length */
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const BROTLI_NUM_LITERAL_SYMBOLS = 256
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const BROTLI_NUM_COMMAND_SYMBOLS = 704
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const BROTLI_NUM_BLOCK_LEN_SYMBOLS = 26
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const BROTLI_MAX_CONTEXT_MAP_SYMBOLS = (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + BROTLI_CONTEXT_MAP_MAX_RLE)
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const 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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const BROTLI_REPEAT_PREVIOUS_CODE_LENGTH = 16
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const BROTLI_REPEAT_ZERO_CODE_LENGTH = 17
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const BROTLI_CODE_LENGTH_CODES = (BROTLI_REPEAT_ZERO_CODE_LENGTH + 1)
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/* "code length of 8 is repeated" */
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const BROTLI_INITIAL_REPEATED_CODE_LENGTH = 8
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/* "Large Window Brotli" */
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const BROTLI_LARGE_MAX_DISTANCE_BITS = 62
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const BROTLI_LARGE_MIN_WBITS = 10
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const BROTLI_LARGE_MAX_WBITS = 30
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/* Specification: 4. Encoding of distances */
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const BROTLI_NUM_DISTANCE_SHORT_CODES = 16
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const BROTLI_MAX_NPOSTFIX = 3
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const BROTLI_MAX_NDIRECT = 120
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const BROTLI_MAX_DISTANCE_BITS = 24
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func BROTLI_DISTANCE_ALPHABET_SIZE(NPOSTFIX uint, NDIRECT uint, MAXNBITS uint) uint {
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return BROTLI_NUM_DISTANCE_SHORT_CODES + NDIRECT + uint(MAXNBITS<<(NPOSTFIX+1))
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}
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/* BROTLI_NUM_DISTANCE_SYMBOLS == 1128 */
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const BROTLI_NUM_DISTANCE_SYMBOLS = 1128
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const BROTLI_MAX_DISTANCE = 0x3FFFFFC
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const BROTLI_MAX_ALLOWED_DISTANCE = 0x7FFFFFFC
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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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const BROTLI_LITERAL_CONTEXT_BITS = 6
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/* 7.2. Context ID for distances */
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const 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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const BROTLI_WINDOW_GAP = 16
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func BROTLI_MAX_BACKWARD_LIMIT(W uint) uint {
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return (uint(1) << W) - BROTLI_WINDOW_GAP
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}
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