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109 lines
4.0 KiB
C
109 lines
4.0 KiB
C
/* Copyright 2015 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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/* Algorithms for distributing the literals and commands of a metablock between
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block types and contexts. */
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#ifndef BROTLI_ENC_METABLOCK_H_
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#define BROTLI_ENC_METABLOCK_H_
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#include <brotli/types.h>
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#include "../common/context.h"
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#include "../common/platform.h"
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#include "block_splitter.h"
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#include "command.h"
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#include "histogram.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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#define BROTLI_MAX_STATIC_CONTEXTS 13
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typedef struct MetaBlockSplit {
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BlockSplit literal_split;
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BlockSplit command_split;
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BlockSplit distance_split;
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uint32_t* literal_context_map;
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size_t literal_context_map_size;
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uint32_t* distance_context_map;
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size_t distance_context_map_size;
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HistogramLiteral* literal_histograms;
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size_t literal_histograms_size;
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HistogramCommand* command_histograms;
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size_t command_histograms_size;
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HistogramDistance* distance_histograms;
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size_t distance_histograms_size;
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} MetaBlockSplit;
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static BROTLI_INLINE void InitMetaBlockSplit(MetaBlockSplit* mb) {
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BrotliInitBlockSplit(&mb->literal_split);
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BrotliInitBlockSplit(&mb->command_split);
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BrotliInitBlockSplit(&mb->distance_split);
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mb->literal_context_map = 0;
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mb->literal_context_map_size = 0;
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mb->distance_context_map = 0;
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mb->distance_context_map_size = 0;
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mb->literal_histograms = 0;
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mb->literal_histograms_size = 0;
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mb->command_histograms = 0;
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mb->command_histograms_size = 0;
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mb->distance_histograms = 0;
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mb->distance_histograms_size = 0;
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}
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static BROTLI_INLINE void DestroyMetaBlockSplit(
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MemoryManager* m, MetaBlockSplit* mb) {
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BrotliDestroyBlockSplit(m, &mb->literal_split);
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BrotliDestroyBlockSplit(m, &mb->command_split);
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BrotliDestroyBlockSplit(m, &mb->distance_split);
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BROTLI_FREE(m, mb->literal_context_map);
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BROTLI_FREE(m, mb->distance_context_map);
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BROTLI_FREE(m, mb->literal_histograms);
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BROTLI_FREE(m, mb->command_histograms);
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BROTLI_FREE(m, mb->distance_histograms);
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}
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/* Uses the slow shortest-path block splitter and does context clustering.
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The distance parameters are dynamically selected based on the commands
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which get recomputed under the new distance parameters. The new distance
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parameters are stored into *params. */
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BROTLI_INTERNAL void BrotliBuildMetaBlock(MemoryManager* m,
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const uint8_t* ringbuffer,
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const size_t pos,
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const size_t mask,
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BrotliEncoderParams* params,
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uint8_t prev_byte,
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uint8_t prev_byte2,
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Command* cmds,
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size_t num_commands,
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ContextType literal_context_mode,
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MetaBlockSplit* mb);
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/* Uses a fast greedy block splitter that tries to merge current block with the
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last or the second last block and uses a static context clustering which
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is the same for all block types. */
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BROTLI_INTERNAL void BrotliBuildMetaBlockGreedy(
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MemoryManager* m, const uint8_t* ringbuffer, size_t pos, size_t mask,
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uint8_t prev_byte, uint8_t prev_byte2, ContextLut literal_context_lut,
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size_t num_contexts, const uint32_t* static_context_map,
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const Command* commands, size_t n_commands, MetaBlockSplit* mb);
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BROTLI_INTERNAL void BrotliOptimizeHistograms(uint32_t num_distance_codes,
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MetaBlockSplit* mb);
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BROTLI_INTERNAL void BrotliInitDistanceParams(BrotliDistanceParams* params,
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uint32_t npostfix, uint32_t ndirect, BROTLI_BOOL large_window);
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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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#endif /* BROTLI_ENC_METABLOCK_H_ */
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