index_hash.h revision 207842
1212795Sdim/** 2212795Sdim * \file lzma/index_hash.h 3212795Sdim * \brief Validates Index by using a hash function 4212795Sdim * 5212795Sdim * Hashing makes it possible to use constant amount of memory to validate 6212795Sdim * Index of arbitrary size. 7212795Sdim */ 8212795Sdim 9212795Sdim/* 10212795Sdim * Author: Lasse Collin 11212795Sdim * 12212795Sdim * This file has been put into the public domain. 13212795Sdim * You can do whatever you want with this file. 14212795Sdim * 15212795Sdim * See ../lzma.h for information about liblzma as a whole. 16212795Sdim */ 17249423Sdim 18212795Sdim#ifndef LZMA_H_INTERNAL 19212795Sdim# error Never include this file directly. Use <lzma.h> instead. 20212795Sdim#endif 21212795Sdim 22212795Sdim/** 23212795Sdim * \brief Opaque data type to hold the Index hash 24218893Sdim */ 25218893Sdimtypedef struct lzma_index_hash_s lzma_index_hash; 26221345Sdim 27221345Sdim 28263508Sdim/** 29263508Sdim * \brief Allocate and initialize a new lzma_index_hash structure 30263508Sdim * 31218893Sdim * If index_hash is NULL, a new lzma_index_hash structure is allocated, 32218893Sdim * initialized, and a pointer to it returned. If allocation fails, NULL 33212795Sdim * is returned. 34212795Sdim * 35212795Sdim * If index_hash is non-NULL, it is reinitialized and the same pointer 36226633Sdim * returned. In this case, return value cannot be NULL or a different 37212795Sdim * pointer than the index_hash that was given as an argument. 38212795Sdim */ 39212795Sdimextern LZMA_API(lzma_index_hash *) lzma_index_hash_init( 40212795Sdim lzma_index_hash *index_hash, lzma_allocator *allocator) 41218893Sdim lzma_nothrow lzma_attr_warn_unused_result; 42212795Sdim 43212795Sdim 44212795Sdim/** 45212795Sdim * \brief Deallocate lzma_index_hash structure 46212795Sdim */ 47212795Sdimextern LZMA_API(void) lzma_index_hash_end( 48212795Sdim lzma_index_hash *index_hash, lzma_allocator *allocator) 49212795Sdim lzma_nothrow; 50212795Sdim 51226633Sdim 52226633Sdim/** 53226633Sdim * \brief Add a new Record to an Index hash 54226633Sdim * 55239462Sdim * \param index Pointer to a lzma_index_hash structure 56239462Sdim * \param unpadded_size Unpadded Size of a Block 57226633Sdim * \param uncompressed_size Uncompressed Size of a Block 58212795Sdim * 59212795Sdim * \return - LZMA_OK 60212795Sdim * - LZMA_DATA_ERROR: Compressed or uncompressed size of the 61212795Sdim * Stream or size of the Index field would grow too big. 62212795Sdim * - LZMA_PROG_ERROR: Invalid arguments or this function is being 63249423Sdim * used when lzma_index_hash_decode() has already been used. 64249423Sdim */ 65249423Sdimextern LZMA_API(lzma_ret) lzma_index_hash_append(lzma_index_hash *index_hash, 66249423Sdim lzma_vli unpadded_size, lzma_vli uncompressed_size) 67249423Sdim lzma_nothrow lzma_attr_warn_unused_result; 68249423Sdim 69249423Sdim 70249423Sdim/** 71249423Sdim * \brief Decode and validate the Index field 72249423Sdim * 73249423Sdim * After telling the sizes of all Blocks with lzma_index_hash_append(), 74249423Sdim * the actual Index field is decoded with this function. Specifically, 75249423Sdim * once decoding of the Index field has been started, no more Records 76249423Sdim * can be added using lzma_index_hash_append(). 77249423Sdim * 78212795Sdim * This function doesn't use lzma_stream structure to pass the input data. 79212795Sdim * Instead, the input buffer is specified using three arguments. This is 80212795Sdim * because it matches better the internal APIs of liblzma. 81212795Sdim * 82212795Sdim * \param index_hash Pointer to a lzma_index_hash structure 83 * \param in Pointer to the beginning of the input buffer 84 * \param in_pos in[*in_pos] is the next byte to process 85 * \param in_size in[in_size] is the first byte not to process 86 * 87 * \return - LZMA_OK: So far good, but more input is needed. 88 * - LZMA_STREAM_END: Index decoded successfully and it matches 89 * the Records given with lzma_index_hash_append(). 90 * - LZMA_DATA_ERROR: Index is corrupt or doesn't match the 91 * information given with lzma_index_hash_append(). 92 * - LZMA_BUF_ERROR: Cannot progress because *in_pos >= in_size. 93 * - LZMA_PROG_ERROR 94 */ 95extern LZMA_API(lzma_ret) lzma_index_hash_decode(lzma_index_hash *index_hash, 96 const uint8_t *in, size_t *in_pos, size_t in_size) 97 lzma_nothrow lzma_attr_warn_unused_result; 98 99 100/** 101 * \brief Get the size of the Index field as bytes 102 * 103 * This is needed to verify the Backward Size field in the Stream Footer. 104 */ 105extern LZMA_API(lzma_vli) lzma_index_hash_size( 106 const lzma_index_hash *index_hash) 107 lzma_nothrow lzma_attr_pure; 108