1 /** 2 * \file lzma/index_hash.h 3 * \brief Validate Index by using a hash function 4 * 5 * Hashing makes it possible to use constant amount of memory to validate 6 * Index of arbitrary size. 7 */ 8 9 /* 10 * Author: Lasse Collin 11 * 12 * This file has been put into the public domain. 13 * You can do whatever you want with this file. 14 * 15 * See ../lzma.h for information about liblzma as a whole. 16 */ 17 18 #ifndef LZMA_H_INTERNAL 19 # error Never include this file directly. Use <lzma.h> instead. 20 #endif 21 22 /** 23 * \brief Opaque data type to hold the Index hash 24 */ 25 typedef struct lzma_index_hash_s lzma_index_hash; 26 27 28 /** 29 * \brief Allocate and initialize a new lzma_index_hash structure 30 * 31 * If index_hash is NULL, a new lzma_index_hash structure is allocated, 32 * initialized, and a pointer to it returned. If allocation fails, NULL 33 * is returned. 34 * 35 * If index_hash is non-NULL, it is reinitialized and the same pointer 36 * returned. In this case, return value cannot be NULL or a different 37 * pointer than the index_hash that was given as an argument. 38 */ 39 extern LZMA_API(lzma_index_hash *) lzma_index_hash_init( 40 lzma_index_hash *index_hash, const lzma_allocator *allocator) 41 lzma_nothrow lzma_attr_warn_unused_result; 42 43 44 /** 45 * \brief Deallocate lzma_index_hash structure 46 */ 47 extern LZMA_API(void) lzma_index_hash_end( 48 lzma_index_hash *index_hash, const lzma_allocator *allocator) 49 lzma_nothrow; 50 51 52 /** 53 * \brief Add a new Record to an Index hash 54 * 55 * \param index Pointer to a lzma_index_hash structure 56 * \param unpadded_size Unpadded Size of a Block 57 * \param uncompressed_size Uncompressed Size of a Block 58 * 59 * \return - LZMA_OK 60 * - LZMA_DATA_ERROR: Compressed or uncompressed size of the 61 * Stream or size of the Index field would grow too big. 62 * - LZMA_PROG_ERROR: Invalid arguments or this function is being 63 * used when lzma_index_hash_decode() has already been used. 64 */ 65 extern LZMA_API(lzma_ret) lzma_index_hash_append(lzma_index_hash *index_hash, 66 lzma_vli unpadded_size, lzma_vli uncompressed_size) 67 lzma_nothrow lzma_attr_warn_unused_result; 68 69 70 /** 71 * \brief Decode and validate the Index field 72 * 73 * After telling the sizes of all Blocks with lzma_index_hash_append(), 74 * the actual Index field is decoded with this function. Specifically, 75 * once decoding of the Index field has been started, no more Records 76 * can be added using lzma_index_hash_append(). 77 * 78 * This function doesn't use lzma_stream structure to pass the input data. 79 * Instead, the input buffer is specified using three arguments. This is 80 * because it matches better the internal APIs of liblzma. 81 * 82 * \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 */ 95 extern 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 */ 105 extern LZMA_API(lzma_vli) lzma_index_hash_size( 106 const lzma_index_hash *index_hash) 107 lzma_nothrow lzma_attr_pure; 108