mirror of
https://github.com/google/brotli.git
synced 2024-11-09 21:50:07 +00:00
a8f5813b84
Documentation: - add note that brotli is a "stream" format, not an archive-like - regenerate .1 with Pandoc Build: - drop legacy "BROTLI_BUILD_PORTABLE" option - drop "BROTLI_SANITIZED" definition Code: - c: comb includes - c/enc: extract encoder state into separate header - c/enc: drop designated q10 codepath - c/enc: dealing better with flushing of empty stream - fix MSVC compilation API: - py: use library version instead of one in version.h - c: add plugable API to report consumed input / produced output - c/java: support "lean" prepared dictionaries (without copy of source)
206 lines
5.5 KiB
C
206 lines
5.5 KiB
C
/* Copyright 2013 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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/* Function to find backward reference copies. */
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#include "backward_references.h"
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#include <brotli/types.h>
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#include "../common/constants.h"
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#include "../common/dictionary.h"
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#include "../common/platform.h"
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#include "command.h"
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#include "compound_dictionary.h"
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#include "dictionary_hash.h"
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#include "encoder_dict.h"
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#include "memory.h"
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#include "quality.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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static BROTLI_INLINE size_t ComputeDistanceCode(size_t distance,
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size_t max_distance,
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const int* dist_cache) {
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if (distance <= max_distance) {
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size_t distance_plus_3 = distance + 3;
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size_t offset0 = distance_plus_3 - (size_t)dist_cache[0];
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size_t offset1 = distance_plus_3 - (size_t)dist_cache[1];
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if (distance == (size_t)dist_cache[0]) {
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return 0;
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} else if (distance == (size_t)dist_cache[1]) {
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return 1;
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} else if (offset0 < 7) {
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return (0x9750468 >> (4 * offset0)) & 0xF;
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} else if (offset1 < 7) {
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return (0xFDB1ACE >> (4 * offset1)) & 0xF;
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} else if (distance == (size_t)dist_cache[2]) {
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return 2;
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} else if (distance == (size_t)dist_cache[3]) {
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return 3;
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}
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}
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return distance + BROTLI_NUM_DISTANCE_SHORT_CODES - 1;
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}
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#define EXPAND_CAT(a, b) CAT(a, b)
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#define CAT(a, b) a ## b
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#define FN(X) EXPAND_CAT(X, HASHER())
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#define EXPORT_FN(X) EXPAND_CAT(X, EXPAND_CAT(PREFIX(), HASHER()))
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#define PREFIX() N
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#define ENABLE_COMPOUND_DICTIONARY 0
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#define HASHER() H2
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H3
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H4
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H5
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H6
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H40
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H41
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H42
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H54
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H35
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H55
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H65
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#undef ENABLE_COMPOUND_DICTIONARY
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#undef PREFIX
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#define PREFIX() D
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#define ENABLE_COMPOUND_DICTIONARY 1
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#define HASHER() H5
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H6
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H40
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H41
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H42
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H55
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#define HASHER() H65
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/* NOLINTNEXTLINE(build/include) */
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#include "backward_references_inc.h"
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#undef HASHER
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#undef ENABLE_COMPOUND_DICTIONARY
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#undef PREFIX
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#undef EXPORT_FN
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#undef FN
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#undef CAT
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#undef EXPAND_CAT
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void BrotliCreateBackwardReferences(size_t num_bytes,
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size_t position, const uint8_t* ringbuffer, size_t ringbuffer_mask,
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ContextLut literal_context_lut, const BrotliEncoderParams* params,
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Hasher* hasher, int* dist_cache, size_t* last_insert_len,
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Command* commands, size_t* num_commands, size_t* num_literals) {
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if (params->dictionary.compound.num_chunks != 0) {
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switch (params->hasher.type) {
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#define CASE_(N) \
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case N: \
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CreateBackwardReferencesDH ## N(num_bytes, \
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position, ringbuffer, ringbuffer_mask, \
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literal_context_lut, params, hasher, dist_cache, \
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last_insert_len, commands, num_commands, num_literals); \
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return;
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CASE_(5)
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CASE_(6)
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CASE_(40)
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CASE_(41)
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CASE_(42)
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CASE_(55)
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CASE_(65)
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#undef CASE_
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default:
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break;
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}
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}
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switch (params->hasher.type) {
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#define CASE_(N) \
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case N: \
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CreateBackwardReferencesNH ## N(num_bytes, \
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position, ringbuffer, ringbuffer_mask, \
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literal_context_lut, params, hasher, dist_cache, \
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last_insert_len, commands, num_commands, num_literals); \
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return;
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FOR_GENERIC_HASHERS(CASE_)
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#undef CASE_
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default:
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break;
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}
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}
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#if defined(__cplusplus) || defined(c_plusplus)
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} /* extern "C" */
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#endif
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