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74 lines
2.6 KiB
C
74 lines
2.6 KiB
C
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/*
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Copyright 2011 Google Inc. All Rights Reserved.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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Author: lode.vandevenne@gmail.com (Lode Vandevenne)
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Author: jyrki.alakuijala@gmail.com (Jyrki Alakuijala)
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*/
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/*
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Functions to choose good boundaries for block splitting. Deflate allows encoding
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the data in multiple blocks, with a separate Huffman tree for each block. The
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Huffman tree itself requires some bytes to encode, so by choosing certain
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blocks, you can either hurt, or enhance compression. These functions choose good
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ones that enhance it.
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*/
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#ifndef ZOPFLI_BLOCKSPLITTER_H_
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#define ZOPFLI_BLOCKSPLITTER_H_
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#include <stdlib.h>
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#include "lz77.h"
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#include "zopfli.h"
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/*
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Does blocksplitting on LZ77 data.
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The output splitpoints are indices in the LZ77 data.
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maxblocks: set a limit to the amount of blocks. Set to 0 to mean no limit.
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*/
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void ZopfliBlockSplitLZ77(const ZopfliOptions* options,
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const ZopfliLZ77Store* lz77, size_t maxblocks,
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size_t** splitpoints, size_t* npoints);
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/*
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Does blocksplitting on uncompressed data.
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The output splitpoints are indices in the uncompressed bytes.
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options: general program options.
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in: uncompressed input data
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instart: where to start splitting
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inend: where to end splitting (not inclusive)
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maxblocks: maximum amount of blocks to split into, or 0 for no limit
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splitpoints: dynamic array to put the resulting split point coordinates into.
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The coordinates are indices in the input array.
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npoints: pointer to amount of splitpoints, for the dynamic array. The amount of
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blocks is the amount of splitpoitns + 1.
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*/
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void ZopfliBlockSplit(const ZopfliOptions* options,
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const unsigned char* in, size_t instart, size_t inend,
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size_t maxblocks, size_t** splitpoints, size_t* npoints);
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/*
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Divides the input into equal blocks, does not even take LZ77 lengths into
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account.
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*/
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void ZopfliBlockSplitSimple(const unsigned char* in,
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size_t instart, size_t inend,
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size_t blocksize,
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size_t** splitpoints, size_t* npoints);
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#endif /* ZOPFLI_BLOCKSPLITTER_H_ */
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