| /* 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. |
| */ |
| uint8_t size_bits_by_length[32]; |
| |
| /* assert(offset[i + 1] == offset[i] + (bits[i] ? (i << bits[i]) : 0)) */ |
| uint32_t offsets_by_length[32]; |
| |
| /* assert(data_size == offsets_by_length[31]) */ |
| 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 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_ */ |