xref: /netbsd-src/external/bsd/zstd/dist/doc/educational_decoder/zstd_decompress.h (revision 3117ece4fc4a4ca4489ba793710b60b0d26bab6c)
1*3117ece4Schristos /*
2*3117ece4Schristos  * Copyright (c) Meta Platforms, Inc. and affiliates.
3*3117ece4Schristos  * All rights reserved.
4*3117ece4Schristos  *
5*3117ece4Schristos  * This source code is licensed under both the BSD-style license (found in the
6*3117ece4Schristos  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7*3117ece4Schristos  * in the COPYING file in the root directory of this source tree).
8*3117ece4Schristos  * You may select, at your option, one of the above-listed licenses.
9*3117ece4Schristos  */
10*3117ece4Schristos 
11*3117ece4Schristos #include <stddef.h>   /* size_t */
12*3117ece4Schristos 
13*3117ece4Schristos /******* EXPOSED TYPES ********************************************************/
14*3117ece4Schristos /*
15*3117ece4Schristos * Contains the parsed contents of a dictionary
16*3117ece4Schristos * This includes Huffman and FSE tables used for decoding and data on offsets
17*3117ece4Schristos */
18*3117ece4Schristos typedef struct dictionary_s dictionary_t;
19*3117ece4Schristos /******* END EXPOSED TYPES ****************************************************/
20*3117ece4Schristos 
21*3117ece4Schristos /******* DECOMPRESSION FUNCTIONS **********************************************/
22*3117ece4Schristos /// Zstandard decompression functions.
23*3117ece4Schristos /// `dst` must point to a space at least as large as the reconstructed output.
24*3117ece4Schristos size_t ZSTD_decompress(void *const dst, const size_t dst_len,
25*3117ece4Schristos                     const void *const src, const size_t src_len);
26*3117ece4Schristos 
27*3117ece4Schristos /// If `dict != NULL` and `dict_len >= 8`, does the same thing as
28*3117ece4Schristos /// `ZSTD_decompress` but uses the provided dict
29*3117ece4Schristos size_t ZSTD_decompress_with_dict(void *const dst, const size_t dst_len,
30*3117ece4Schristos                               const void *const src, const size_t src_len,
31*3117ece4Schristos                               dictionary_t* parsed_dict);
32*3117ece4Schristos 
33*3117ece4Schristos /// Get the decompressed size of an input stream so memory can be allocated in
34*3117ece4Schristos /// advance
35*3117ece4Schristos /// Returns -1 if the size can't be determined
36*3117ece4Schristos /// Assumes decompression of a single frame
37*3117ece4Schristos size_t ZSTD_get_decompressed_size(const void *const src, const size_t src_len);
38*3117ece4Schristos /******* END DECOMPRESSION FUNCTIONS ******************************************/
39*3117ece4Schristos 
40*3117ece4Schristos /******* DICTIONARY MANAGEMENT ***********************************************/
41*3117ece4Schristos /*
42*3117ece4Schristos  * Return a valid dictionary_t pointer for use with dictionary initialization
43*3117ece4Schristos  * or decompression
44*3117ece4Schristos  */
45*3117ece4Schristos dictionary_t* create_dictionary(void);
46*3117ece4Schristos 
47*3117ece4Schristos /*
48*3117ece4Schristos  * Parse a provided dictionary blob for use in decompression
49*3117ece4Schristos  * `src` -- must point to memory space representing the dictionary
50*3117ece4Schristos  * `src_len` -- must provide the dictionary size
51*3117ece4Schristos  * `dict` -- will contain the parsed contents of the dictionary and
52*3117ece4Schristos  *        can be used for decompression
53*3117ece4Schristos  */
54*3117ece4Schristos void parse_dictionary(dictionary_t *const dict, const void *src,
55*3117ece4Schristos                              size_t src_len);
56*3117ece4Schristos 
57*3117ece4Schristos /*
58*3117ece4Schristos  * Free internal Huffman tables, FSE tables, and dictionary content
59*3117ece4Schristos  */
60*3117ece4Schristos void free_dictionary(dictionary_t *const dict);
61*3117ece4Schristos /******* END DICTIONARY MANAGEMENT *******************************************/
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