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      1 /*
      2 Copyright 2011 Google Inc. All Rights Reserved.
      3 
      4 Licensed under the Apache License, Version 2.0 (the "License");
      5 you may not use this file except in compliance with the License.
      6 You may obtain a copy of the License at
      7 
      8     http://www.apache.org/licenses/LICENSE-2.0
      9 
     10 Unless required by applicable law or agreed to in writing, software
     11 distributed under the License is distributed on an "AS IS" BASIS,
     12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 See the License for the specific language governing permissions and
     14 limitations under the License.
     15 
     16 Author: lode.vandevenne (at) gmail.com (Lode Vandevenne)
     17 Author: jyrki.alakuijala (at) gmail.com (Jyrki Alakuijala)
     18 */
     19 
     20 #ifndef ZOPFLI_ZOPFLI_H_
     21 #define ZOPFLI_ZOPFLI_H_
     22 
     23 #include <stddef.h>
     24 #include <stdlib.h> /* for size_t */
     25 
     26 #ifdef __cplusplus
     27 extern "C" {
     28 #endif
     29 
     30 /*
     31 Options used throughout the program.
     32 */
     33 typedef struct ZopfliOptions {
     34   /* Whether to print output */
     35   int verbose;
     36 
     37   /* Whether to print more detailed output */
     38   int verbose_more;
     39 
     40   /*
     41   Maximum amount of times to rerun forward and backward pass to optimize LZ77
     42   compression cost. Good values: 10, 15 for small files, 5 for files over
     43   several MB in size or it will be too slow.
     44   */
     45   int numiterations;
     46 
     47   /*
     48   If true, splits the data in multiple deflate blocks with optimal choice
     49   for the block boundaries. Block splitting gives better compression. Default:
     50   true (1).
     51   */
     52   int blocksplitting;
     53 
     54   /*
     55   If true, chooses the optimal block split points only after doing the iterative
     56   LZ77 compression. If false, chooses the block split points first, then does
     57   iterative LZ77 on each individual block. Depending on the file, either first
     58   or last gives the best compression. Default: false (0).
     59   */
     60   int blocksplittinglast;
     61 
     62   /*
     63   Maximum amount of blocks to split into (0 for unlimited, but this can give
     64   extreme results that hurt compression on some files). Default value: 15.
     65   */
     66   int blocksplittingmax;
     67 } ZopfliOptions;
     68 
     69 /* Initializes options with default values. */
     70 void ZopfliInitOptions(ZopfliOptions* options);
     71 
     72 /* Output format */
     73 typedef enum {
     74   ZOPFLI_FORMAT_GZIP,
     75   ZOPFLI_FORMAT_ZLIB,
     76   ZOPFLI_FORMAT_DEFLATE
     77 } ZopfliFormat;
     78 
     79 /*
     80 Compresses according to the given output format and appends the result to the
     81 output.
     82 
     83 options: global program options
     84 output_type: the output format to use
     85 out: pointer to the dynamic output array to which the result is appended. Must
     86   be freed after use
     87 outsize: pointer to the dynamic output array size
     88 */
     89 void ZopfliCompress(const ZopfliOptions* options, ZopfliFormat output_type,
     90                     const unsigned char* in, size_t insize,
     91                     unsigned char** out, size_t* outsize);
     92 
     93 #ifdef __cplusplus
     94 }  // extern "C"
     95 #endif
     96 
     97 #endif  /* ZOPFLI_ZOPFLI_H_ */
     98