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60c24c0c2d
This commit contains a batch of changes that were made to the Brotli
compression algorithm in the last month. Most important changes:
* Updated spec
* Changed Huffman code length alphabet to use run length codes more
efficiently, based on a suggestion by Robert Obryk
* Changed encoding of the number of Huffman code lengths (HLEN)
* Changed encoding of the number of Huffman trees (NTREES)
* Added support for uncompressed meta-blocks
76 lines
2.3 KiB
C++
76 lines
2.3 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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// API for Brotli compression
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#ifndef BROTLI_ENC_ENCODE_H_
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#define BROTLI_ENC_ENCODE_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <string>
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#include <vector>
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#include "./hash.h"
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#include "./ringbuffer.h"
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namespace brotli {
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class BrotliCompressor {
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public:
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BrotliCompressor();
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~BrotliCompressor();
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// Writes the stream header into the internal output buffer.
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void WriteStreamHeader();
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// Encodes the data in input_buffer as a meta-block and writes it to
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// encoded_buffer and sets *encoded_size to the number of bytes that was
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// written.
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void WriteMetaBlock(const size_t input_size,
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const uint8_t* input_buffer,
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const bool is_last,
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size_t* encoded_size,
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uint8_t* encoded_buffer);
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// Writes a zero-length meta-block with end-of-input bit set to the
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// internal output buffer and copies the output buffer to encoded_buffer and
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// sets *encoded_size to the number of bytes written.
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void FinishStream(size_t* encoded_size, uint8_t* encoded_buffer);
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private:
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int window_bits_;
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Hasher* hasher_;
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int dist_ringbuffer_[4];
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size_t dist_ringbuffer_idx_;
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size_t input_pos_;
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RingBuffer ringbuffer_;
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std::vector<float> literal_cost_;
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int storage_ix_;
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uint8_t* storage_;
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};
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// Compresses the data in input_buffer into encoded_buffer, and sets
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// *encoded_size to the compressed length.
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// Returns 0 if there was an error and 1 otherwise.
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int BrotliCompressBuffer(size_t input_size,
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const uint8_t* input_buffer,
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size_t* encoded_size,
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uint8_t* encoded_buffer);
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} // namespace brotli
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#endif // BROTLI_ENC_ENCODE_H_
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