name : shared_dictionary.h /* Copyright 2017 Google Inc. All Rights Reserved. Distributed under MIT license. See file LICENSE for detail or copy at https://opensource.org/licenses/MIT */ /* (Opaque) Shared Dictionary definition and utilities. */ #ifndef BROTLI_COMMON_SHARED_DICTIONARY_H_ #define BROTLI_COMMON_SHARED_DICTIONARY_H_ #include <brotli/port.h> #include <brotli/types.h> #if defined(__cplusplus) || defined(c_plusplus) extern "C" { #endif #define SHARED_BROTLI_MIN_DICTIONARY_WORD_LENGTH 4 #define SHARED_BROTLI_MAX_DICTIONARY_WORD_LENGTH 31 #define SHARED_BROTLI_NUM_DICTIONARY_CONTEXTS 64 #define SHARED_BROTLI_MAX_COMPOUND_DICTS 15 /** * Opaque structure that holds shared dictionary data. * * Allocated and initialized with ::BrotliSharedDictionaryCreateInstance. * Cleaned up and deallocated with ::BrotliSharedDictionaryDestroyInstance. */ typedef struct BrotliSharedDictionaryStruct BrotliSharedDictionary; /** * Input data type for ::BrotliSharedDictionaryAttach. */ typedef enum BrotliSharedDictionaryType { /** Raw LZ77 prefix dictionary. */ BROTLI_SHARED_DICTIONARY_RAW = 0, /** Serialized shared dictionary. * * DO NOT USE: methods accepting this value will fail. */ BROTLI_SHARED_DICTIONARY_SERIALIZED = 1 } BrotliSharedDictionaryType; /** * Creates an instance of ::BrotliSharedDictionary. * * Fresh instance has default word dictionary and transforms * and no LZ77 prefix dictionary. * * @p alloc_func and @p free_func @b MUST be both zero or both non-zero. In the * case they are both zero, default memory allocators are used. @p opaque is * passed to @p alloc_func and @p free_func when they are called. @p free_func * has to return without doing anything when asked to free a NULL pointer. * * @param alloc_func custom memory allocation function * @param free_func custom memory free function * @param opaque custom memory manager handle * @returns @c 0 if instance can not be allocated or initialized * @returns pointer to initialized ::BrotliSharedDictionary otherwise */ BROTLI_COMMON_API BrotliSharedDictionary* BrotliSharedDictionaryCreateInstance( brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque); /** * Deinitializes and frees ::BrotliSharedDictionary instance. * * @param dict shared dictionary instance to be cleaned up and deallocated */ BROTLI_COMMON_API void BrotliSharedDictionaryDestroyInstance( BrotliSharedDictionary* dict); /** * Attaches dictionary to a given instance of ::BrotliSharedDictionary. * * Dictionary to be attached is represented in a serialized format as a region * of memory. * * Provided data it partially referenced by a resulting (compound) dictionary, * and should be kept untouched, while at least one compound dictionary uses it. * This way memory overhead is kept minimal by the cost of additional resource * management. * * @param dict dictionary to extend * @param type type of dictionary to attach * @param data_size size of @p data * @param data serialized dictionary of type @p type, with at least @p data_size * addressable bytes * @returns ::BROTLI_TRUE if provided dictionary is successfully attached * @returns ::BROTLI_FALSE otherwise */ BROTLI_COMMON_API BROTLI_BOOL BrotliSharedDictionaryAttach( BrotliSharedDictionary* dict, BrotliSharedDictionaryType type, size_t data_size, const uint8_t data[BROTLI_ARRAY_PARAM(data_size)]); #if defined(__cplusplus) || defined(c_plusplus) } /* extern "C" */ #endif #endif /* BROTLI_COMMON_SHARED_DICTIONARY_H_ */