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62 lines
2.2 KiB
C
62 lines
2.2 KiB
C
/*
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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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The squeeze functions do enhanced LZ77 compression by optimal parsing with a
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cost model, rather than greedily choosing the longest length or using a single
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step of lazy matching like regular implementations.
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Since the cost model is based on the Huffman tree that can only be calculated
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after the LZ77 data is generated, there is a chicken and egg problem, and
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multiple runs are done with updated cost models to converge to a better
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solution.
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*/
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#ifndef ZOPFLI_SQUEEZE_H_
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#define ZOPFLI_SQUEEZE_H_
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#include "lz77.h"
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/*
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Calculates lit/len and dist pairs for given data.
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If instart is larger than 0, it uses values before instart as starting
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dictionary.
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*/
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void ZopfliLZ77Optimal(ZopfliBlockState *s,
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const unsigned char* in, size_t instart, size_t inend,
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int numiterations,
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ZopfliLZ77Store* store);
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/*
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Does the same as ZopfliLZ77Optimal, but optimized for the fixed tree of the
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deflate standard.
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The fixed tree never gives the best compression. But this gives the best
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possible LZ77 encoding possible with the fixed tree.
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This does not create or output any fixed tree, only LZ77 data optimized for
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using with a fixed tree.
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If instart is larger than 0, it uses values before instart as starting
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dictionary.
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*/
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void ZopfliLZ77OptimalFixed(ZopfliBlockState *s,
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const unsigned char* in,
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size_t instart, size_t inend,
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ZopfliLZ77Store* store);
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#endif /* ZOPFLI_SQUEEZE_H_ */
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