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/* 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_ */
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