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/** * \file lzma/index_hash.h * \brief Validate Index by using a hash function * * Hashing makes it possible to use constant amount of memory to validate * Index of arbitrary size. */ /* * Author: Lasse Collin * * This file has been put into the public domain. * You can do whatever you want with this file. * * See ../lzma.h for information about liblzma as a whole. */ #ifndef LZMA_H_INTERNAL # error Never include this file directly. Use <lzma.h> instead. #endif /** * \brief Opaque data type to hold the Index hash */ typedef struct lzma_index_hash_s lzma_index_hash; /** * \brief Allocate and initialize a new lzma_index_hash structure * * If index_hash is NULL, a new lzma_index_hash structure is allocated, * initialized, and a pointer to it returned. If allocation fails, NULL * is returned. * * If index_hash is non-NULL, it is reinitialized and the same pointer * returned. In this case, return value cannot be NULL or a different * pointer than the index_hash that was given as an argument. */ extern LZMA_API(lzma_index_hash *) lzma_index_hash_init( lzma_index_hash *index_hash, const lzma_allocator *allocator) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Deallocate lzma_index_hash structure */ extern LZMA_API(void) lzma_index_hash_end( lzma_index_hash *index_hash, const lzma_allocator *allocator) lzma_nothrow; /** * \brief Add a new Record to an Index hash * * \param index Pointer to a lzma_index_hash structure * \param unpadded_size Unpadded Size of a Block * \param uncompressed_size Uncompressed Size of a Block * * \return - LZMA_OK * - LZMA_DATA_ERROR: Compressed or uncompressed size of the * Stream or size of the Index field would grow too big. * - LZMA_PROG_ERROR: Invalid arguments or this function is being * used when lzma_index_hash_decode() has already been used. */ extern LZMA_API(lzma_ret) lzma_index_hash_append(lzma_index_hash *index_hash, lzma_vli unpadded_size, lzma_vli uncompressed_size) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Decode and validate the Index field * * After telling the sizes of all Blocks with lzma_index_hash_append(), * the actual Index field is decoded with this function. Specifically, * once decoding of the Index field has been started, no more Records * can be added using lzma_index_hash_append(). * * This function doesn't use lzma_stream structure to pass the input data. * Instead, the input buffer is specified using three arguments. This is * because it matches better the internal APIs of liblzma. * * \param index_hash Pointer to a lzma_index_hash structure * \param in Pointer to the beginning of the input buffer * \param in_pos in[*in_pos] is the next byte to process * \param in_size in[in_size] is the first byte not to process * * \return - LZMA_OK: So far good, but more input is needed. * - LZMA_STREAM_END: Index decoded successfully and it matches * the Records given with lzma_index_hash_append(). * - LZMA_DATA_ERROR: Index is corrupt or doesn't match the * information given with lzma_index_hash_append(). * - LZMA_BUF_ERROR: Cannot progress because *in_pos >= in_size. * - LZMA_PROG_ERROR */ extern LZMA_API(lzma_ret) lzma_index_hash_decode(lzma_index_hash *index_hash, const uint8_t *in, size_t *in_pos, size_t in_size) lzma_nothrow lzma_attr_warn_unused_result; /** * \brief Get the size of the Index field as bytes * * This is needed to verify the Backward Size field in the Stream Footer. */ extern LZMA_API(lzma_vli) lzma_index_hash_size( const lzma_index_hash *index_hash) lzma_nothrow lzma_attr_pure;