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e7650080a8
This commit contains a batch of changes that were made to the Brotli compression algorithm in the last month. Most important changes: * Format change: don't push distances representing static dictionary words to the distance cache. * Fix decoder invalid memory access bug caused by building a non-complete Huffman tree. * Add a mode parameter to the encoder interface. * Use different hashers for text and font mode. * Add a heuristics to the hasher for skipping non-compressible data. * Exhaustive search of static dictionary during backward reference search.
51 lines
1.7 KiB
C++
51 lines
1.7 KiB
C++
// Copyright 2013 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// This class models a sequence of literals and a backward reference copy.
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#ifndef BROTLI_ENC_COMMAND_H_
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#define BROTLI_ENC_COMMAND_H_
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#include <stdint.h>
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namespace brotli {
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// Command holds a sequence of literals and a backward reference copy.
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class Command {
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public:
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// distance_code_ is initialized to 17 because it refers to the distance
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// code of a backward distance of 1, this way the last insert-only command
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// won't use the last-distance short code, and accordingly distance_prefix_ is
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// set to 16
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Command() : insert_length_(0), copy_length_(0), copy_length_code_(0),
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copy_distance_(0), distance_code_(17),
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distance_prefix_(16), command_prefix_(0),
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distance_extra_bits_(0), distance_extra_bits_value_(0) {}
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uint32_t insert_length_;
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uint32_t copy_length_;
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uint32_t copy_length_code_;
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uint32_t copy_distance_;
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// Values <= 16 are short codes, values > 16 are distances shifted by 16.
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uint32_t distance_code_;
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uint16_t distance_prefix_;
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uint16_t command_prefix_;
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int distance_extra_bits_;
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uint32_t distance_extra_bits_value_;
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};
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} // namespace brotli
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#endif // BROTLI_ENC_COMMAND_H_
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