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b3d3723f62
This commit adopts the backward reference search algorithm from the zopfli project (see https://github.com/google/zopfli) to brotli. This slower backward reference search is run only in quality 11 and it runs two iterations of entropy cost modeling and shortest path search. As a result, the original backward reference search function can be simplified a bit, since we can remove some heuristics that were replaced with the zopfli-style search.
52 lines
1.9 KiB
C++
52 lines
1.9 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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// Function to find backward reference copies.
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#ifndef BROTLI_ENC_BACKWARD_REFERENCES_H_
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#define BROTLI_ENC_BACKWARD_REFERENCES_H_
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#include <stdint.h>
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#include <vector>
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#include "./hash.h"
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#include "./command.h"
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namespace brotli {
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// "commands" points to the next output command to write to, "*num_commands" is
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// initially the total amount of commands output by previous
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// CreateBackwardReferences calls, and must be incremented by the amount written
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// by this call.
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void CreateBackwardReferences(size_t num_bytes,
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size_t position,
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const uint8_t* ringbuffer,
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size_t ringbuffer_mask,
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const float* literal_cost,
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size_t literal_cost_mask,
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const size_t max_backward_limit,
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const double base_min_score,
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const int quality,
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Hashers* hashers,
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int hash_type,
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int* dist_cache,
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int* last_insert_len,
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Command* commands,
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int* num_commands,
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int* num_literals);
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} // namespace brotli
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#endif // BROTLI_ENC_BACKWARD_REFERENCES_H_
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