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// Copyright 2015 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Algorithms for distributing the literals and commands of a metablock between
// block types and contexts.
#ifndef BROTLI_ENC_METABLOCK_H_
#define BROTLI_ENC_METABLOCK_H_
#include <vector>
#include "./command.h"
#include "./histogram.h"
namespace brotli {
struct BlockSplit {
BlockSplit() : num_types(0) {}
int num_types;
std::vector<int> types;
std::vector<int> lengths;
};
struct MetaBlockSplit {
BlockSplit literal_split;
BlockSplit command_split;
BlockSplit distance_split;
std::vector<int> literal_context_map;
std::vector<int> distance_context_map;
std::vector<HistogramLiteral> literal_histograms;
std::vector<HistogramCommand> command_histograms;
std::vector<HistogramDistance> distance_histograms;
};
// Uses the slow shortest-path block splitter and does context clustering.
void BuildMetaBlock(const uint8_t* ringbuffer,
const size_t pos,
const size_t mask,
uint8_t prev_byte,
uint8_t prev_byte2,
const Command* cmds,
size_t num_commands,
int literal_context_mode,
MetaBlockSplit* mb);
// Uses a fast greedy block splitter that tries to merge current block with the
// last or the second last block and does not do any context modeling.
void BuildMetaBlockGreedy(const uint8_t* ringbuffer,
size_t pos,
size_t mask,
const Command *commands,
size_t n_commands,
MetaBlockSplit* mb);
// Uses a fast greedy block splitter that tries to merge current block with the
// last or the second last block and uses a static context clustering which
// is the same for all block types.
void BuildMetaBlockGreedyWithContexts(const uint8_t* ringbuffer,
size_t pos,
size_t mask,
uint8_t prev_byte,
uint8_t prev_byte2,
int literal_context_mode,
int num_contexts,
const int* static_context_map,
const Command *commands,
size_t n_commands,
MetaBlockSplit* mb);
void OptimizeHistograms(int num_direct_distance_codes,
int distance_postfix_bits,
MetaBlockSplit* mb);
} // namespace brotli
#endif // BROTLI_ENC_METABLOCK_H_