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Diffstat (limited to 'Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/common/constants.h')
-rw-r--r-- | Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/common/constants.h | 200 |
1 files changed, 0 insertions, 200 deletions
diff --git a/Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/common/constants.h b/Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/common/constants.h deleted file mode 100644 index e848195a0dc..00000000000 --- a/Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/common/constants.h +++ /dev/null @@ -1,200 +0,0 @@ -/* Copyright 2016 Google Inc. All Rights Reserved. - - Distributed under MIT license. - See file LICENSE for detail or copy at https://opensource.org/licenses/MIT -*/ - -/** - * @file - * Common constants used in decoder and encoder API. - */ - -#ifndef BROTLI_COMMON_CONSTANTS_H_ -#define BROTLI_COMMON_CONSTANTS_H_ - -#include "./platform.h" -#include <brotli/port.h> -#include <brotli/types.h> - -/* Specification: 7.3. Encoding of the context map */ -#define BROTLI_CONTEXT_MAP_MAX_RLE 16 - -/* Specification: 2. Compressed representation overview */ -#define BROTLI_MAX_NUMBER_OF_BLOCK_TYPES 256 - -/* Specification: 3.3. Alphabet sizes: insert-and-copy length */ -#define BROTLI_NUM_LITERAL_SYMBOLS 256 -#define BROTLI_NUM_COMMAND_SYMBOLS 704 -#define BROTLI_NUM_BLOCK_LEN_SYMBOLS 26 -#define BROTLI_MAX_CONTEXT_MAP_SYMBOLS (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + \ - BROTLI_CONTEXT_MAP_MAX_RLE) -#define BROTLI_MAX_BLOCK_TYPE_SYMBOLS (BROTLI_MAX_NUMBER_OF_BLOCK_TYPES + 2) - -/* Specification: 3.5. Complex prefix codes */ -#define BROTLI_REPEAT_PREVIOUS_CODE_LENGTH 16 -#define BROTLI_REPEAT_ZERO_CODE_LENGTH 17 -#define BROTLI_CODE_LENGTH_CODES (BROTLI_REPEAT_ZERO_CODE_LENGTH + 1) -/* "code length of 8 is repeated" */ -#define BROTLI_INITIAL_REPEATED_CODE_LENGTH 8 - -/* "Large Window Brotli" */ - -/** - * The theoretical maximum number of distance bits specified for large window - * brotli, for 64-bit encoders and decoders. Even when in practice 32-bit - * encoders and decoders only support up to 30 max distance bits, the value is - * set to 62 because it affects the large window brotli file format. - * Specifically, it affects the encoding of simple huffman tree for distances, - * see Specification RFC 7932 chapter 3.4. - */ -#define BROTLI_LARGE_MAX_DISTANCE_BITS 62U -#define BROTLI_LARGE_MIN_WBITS 10 -/** - * The maximum supported large brotli window bits by the encoder and decoder. - * Large window brotli allows up to 62 bits, however the current encoder and - * decoder, designed for 32-bit integers, only support up to 30 bits maximum. - */ -#define BROTLI_LARGE_MAX_WBITS 30 - -/* Specification: 4. Encoding of distances */ -#define BROTLI_NUM_DISTANCE_SHORT_CODES 16 -/** - * Maximal number of "postfix" bits. - * - * Number of "postfix" bits is stored as 2 bits in meta-block header. - */ -#define BROTLI_MAX_NPOSTFIX 3 -#define BROTLI_MAX_NDIRECT 120 -#define BROTLI_MAX_DISTANCE_BITS 24U -#define BROTLI_DISTANCE_ALPHABET_SIZE(NPOSTFIX, NDIRECT, MAXNBITS) ( \ - BROTLI_NUM_DISTANCE_SHORT_CODES + (NDIRECT) + \ - ((MAXNBITS) << ((NPOSTFIX) + 1))) -/* BROTLI_NUM_DISTANCE_SYMBOLS == 1128 */ -#define BROTLI_NUM_DISTANCE_SYMBOLS \ - BROTLI_DISTANCE_ALPHABET_SIZE( \ - BROTLI_MAX_NDIRECT, BROTLI_MAX_NPOSTFIX, BROTLI_LARGE_MAX_DISTANCE_BITS) - -/* ((1 << 26) - 4) is the maximal distance that can be expressed in RFC 7932 - brotli stream using NPOSTFIX = 0 and NDIRECT = 0. With other NPOSTFIX and - NDIRECT values distances up to ((1 << 29) + 88) could be expressed. */ -#define BROTLI_MAX_DISTANCE 0x3FFFFFC - -/* ((1 << 31) - 4) is the safe distance limit. Using this number as a limit - allows safe distance calculation without overflows, given the distance - alphabet size is limited to corresponding size - (see kLargeWindowDistanceCodeLimits). */ -#define BROTLI_MAX_ALLOWED_DISTANCE 0x7FFFFFFC - - -/* Specification: 4. Encoding of Literal Insertion Lengths and Copy Lengths */ -#define BROTLI_NUM_INS_COPY_CODES 24 - -/* 7.1. Context modes and context ID lookup for literals */ -/* "context IDs for literals are in the range of 0..63" */ -#define BROTLI_LITERAL_CONTEXT_BITS 6 - -/* 7.2. Context ID for distances */ -#define BROTLI_DISTANCE_CONTEXT_BITS 2 - -/* 9.1. Format of the Stream Header */ -/* Number of slack bytes for window size. Don't confuse - with BROTLI_NUM_DISTANCE_SHORT_CODES. */ -#define BROTLI_WINDOW_GAP 16 -#define BROTLI_MAX_BACKWARD_LIMIT(W) (((size_t)1 << (W)) - BROTLI_WINDOW_GAP) - -typedef struct BrotliDistanceCodeLimit { - uint32_t max_alphabet_size; - uint32_t max_distance; -} BrotliDistanceCodeLimit; - -/* This function calculates maximal size of distance alphabet, such that the - distances greater than the given values can not be represented. - - This limits are designed to support fast and safe 32-bit decoders. - "32-bit" means that signed integer values up to ((1 << 31) - 1) could be - safely expressed. - - Brotli distance alphabet symbols do not represent consecutive distance - ranges. Each distance alphabet symbol (excluding direct distances and short - codes), represent interleaved (for NPOSTFIX > 0) range of distances. - A "group" of consecutive (1 << NPOSTFIX) symbols represent non-interleaved - range. Two consecutive groups require the same amount of "extra bits". - - It is important that distance alphabet represents complete "groups". - To avoid complex logic on encoder side about interleaved ranges - it was decided to restrict both sides to complete distance code "groups". - */ -BROTLI_UNUSED_FUNCTION BrotliDistanceCodeLimit BrotliCalculateDistanceCodeLimit( - uint32_t max_distance, uint32_t npostfix, uint32_t ndirect) { - BrotliDistanceCodeLimit result; - /* Marking this function as unused, because not all files - including "constants.h" use it -> compiler warns about that. */ - BROTLI_UNUSED(&BrotliCalculateDistanceCodeLimit); - if (max_distance <= ndirect) { - /* This case never happens / exists only for the sake of completeness. */ - result.max_alphabet_size = max_distance + BROTLI_NUM_DISTANCE_SHORT_CODES; - result.max_distance = max_distance; - return result; - } else { - /* The first prohibited value. */ - uint32_t forbidden_distance = max_distance + 1; - /* Subtract "directly" encoded region. */ - uint32_t offset = forbidden_distance - ndirect - 1; - uint32_t ndistbits = 0; - uint32_t tmp; - uint32_t half; - uint32_t group; - /* Postfix for the last dcode in the group. */ - uint32_t postfix = (1u << npostfix) - 1; - uint32_t extra; - uint32_t start; - /* Remove postfix and "head-start". */ - offset = (offset >> npostfix) + 4; - /* Calculate the number of distance bits. */ - tmp = offset / 2; - /* Poor-man's log2floor, to avoid extra dependencies. */ - while (tmp != 0) {ndistbits++; tmp = tmp >> 1;} - /* One bit is covered with subrange addressing ("half"). */ - ndistbits--; - /* Find subrange. */ - half = (offset >> ndistbits) & 1; - /* Calculate the "group" part of dcode. */ - group = ((ndistbits - 1) << 1) | half; - /* Calculated "group" covers the prohibited distance value. */ - if (group == 0) { - /* This case is added for correctness; does not occur for limit > 128. */ - result.max_alphabet_size = ndirect + BROTLI_NUM_DISTANCE_SHORT_CODES; - result.max_distance = ndirect; - return result; - } - /* Decrement "group", so it is the last permitted "group". */ - group--; - /* After group was decremented, ndistbits and half must be recalculated. */ - ndistbits = (group >> 1) + 1; - /* The last available distance in the subrange has all extra bits set. */ - extra = (1u << ndistbits) - 1; - /* Calculate region start. NB: ndistbits >= 1. */ - start = (1u << (ndistbits + 1)) - 4; - /* Move to subregion. */ - start += (group & 1) << ndistbits; - /* Calculate the alphabet size. */ - result.max_alphabet_size = ((group << npostfix) | postfix) + ndirect + - BROTLI_NUM_DISTANCE_SHORT_CODES + 1; - /* Calculate the maximal distance representable by alphabet. */ - result.max_distance = ((start + extra) << npostfix) + postfix + ndirect + 1; - return result; - } -} - -/* Represents the range of values belonging to a prefix code: - [offset, offset + 2^nbits) */ -typedef struct { - uint16_t offset; - uint8_t nbits; -} BrotliPrefixCodeRange; - -/* "Soft-private", it is exported, but not "advertised" as API. */ -BROTLI_COMMON_API extern const BrotliPrefixCodeRange - _kBrotliPrefixCodeRanges[BROTLI_NUM_BLOCK_LEN_SYMBOLS]; - -#endif /* BROTLI_COMMON_CONSTANTS_H_ */ |