65 lines
1.9 KiB
C
65 lines
1.9 KiB
C
/* Copyright 2013 Google Inc. All Rights Reserved.
|
|
|
|
Distributed under MIT license.
|
|
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
|
|
*/
|
|
|
|
/* Collection of static dictionary words. */
|
|
|
|
#ifndef BROTLI_COMMON_DICTIONARY_H_
|
|
#define BROTLI_COMMON_DICTIONARY_H_
|
|
|
|
#include <brotli/port.h>
|
|
#include <brotli/types.h>
|
|
|
|
#if defined(__cplusplus) || defined(c_plusplus)
|
|
extern "C" {
|
|
#endif
|
|
|
|
typedef struct BrotliDictionary {
|
|
/**
|
|
* Number of bits to encode index of dictionary word in a bucket.
|
|
*
|
|
* Specification: Appendix A. Static Dictionary Data
|
|
*
|
|
* Words in a dictionary are bucketed by length.
|
|
* @c 0 means that there are no words of a given length.
|
|
* Dictionary consists of words with length of [4..24] bytes.
|
|
* Values at [0..3] and [25..31] indices should not be addressed.
|
|
*/
|
|
const uint8_t size_bits_by_length[32];
|
|
|
|
/* assert(offset[i + 1] == offset[i] + (bits[i] ? (i << bits[i]) : 0)) */
|
|
const uint32_t offsets_by_length[32];
|
|
|
|
/* assert(data_size == offsets_by_length[31]) */
|
|
const size_t data_size;
|
|
|
|
/* Data array is not bound, and should obey to size_bits_by_length values.
|
|
Specified size matches default (RFC 7932) dictionary. Its size is
|
|
defined by data_size */
|
|
const uint8_t* data;
|
|
} BrotliDictionary;
|
|
|
|
BROTLI_COMMON_API extern const BrotliDictionary* BrotliGetDictionary(void);
|
|
|
|
/**
|
|
* Sets dictionary data.
|
|
*
|
|
* When dictionary data is already set / present, this method is no-op.
|
|
*
|
|
* Dictionary data MUST be provided before BrotliGetDictionary is invoked.
|
|
* This method is used ONLY in multi-client environment (e.g. C + Java),
|
|
* to reduce storage by sharing single dictionary between implementations.
|
|
*/
|
|
BROTLI_COMMON_API void BrotliSetDictionaryData(const uint8_t* data);
|
|
|
|
#define BROTLI_MIN_DICTIONARY_WORD_LENGTH 4
|
|
#define BROTLI_MAX_DICTIONARY_WORD_LENGTH 24
|
|
|
|
#if defined(__cplusplus) || defined(c_plusplus)
|
|
} /* extern "C" */
|
|
#endif
|
|
|
|
#endif /* BROTLI_COMMON_DICTIONARY_H_ */
|