1 /* SPDX-License-Identifier: 0BSD */ 2 3 /** 4 * \file lzma/index_hash.h 5 * \brief Validate Index by using a hash function 6 * \note Never include this file directly. Use <lzma.h> instead. 7 * 8 * Hashing makes it possible to use constant amount of memory to validate 9 * Index of arbitrary size. 10 */ 11 12 /* 13 * Author: Lasse Collin 14 */ 15 16 #ifndef LZMA_H_INTERNAL 17 # error Never include this file directly. Use <lzma.h> instead. 18 #endif 19 20 /** 21 * \brief Opaque data type to hold the Index hash 22 */ 23 typedef struct lzma_index_hash_s lzma_index_hash; 24 25 26 /** 27 * \brief Allocate and initialize a new lzma_index_hash structure 28 * 29 * If index_hash is NULL, this function allocates and initializes a new 30 * lzma_index_hash structure and returns a pointer to it. If allocation 31 * fails, NULL is returned. 32 * 33 * If index_hash is non-NULL, this function reinitializes the lzma_index_hash 34 * structure and returns the same pointer. In this case, return value cannot 35 * be NULL or a different pointer than the index_hash that was given as 36 * an argument. 37 * 38 * \param index_hash Pointer to a lzma_index_hash structure or NULL. 39 * \param allocator lzma_allocator for custom allocator functions. 40 * Set to NULL to use malloc() and free(). 41 * 42 * \return Initialized lzma_index_hash structure on success or 43 * NULL on failure. 44 */ 45 extern LZMA_API(lzma_index_hash *) lzma_index_hash_init( 46 lzma_index_hash *index_hash, const lzma_allocator *allocator) 47 lzma_nothrow lzma_attr_warn_unused_result; 48 49 50 /** 51 * \brief Deallocate lzma_index_hash structure 52 * 53 * \param index_hash Pointer to a lzma_index_hash structure to free. 54 * \param allocator lzma_allocator for custom allocator functions. 55 * Set to NULL to use malloc() and free(). 56 */ 57 extern LZMA_API(void) lzma_index_hash_end( 58 lzma_index_hash *index_hash, const lzma_allocator *allocator) 59 lzma_nothrow; 60 61 62 /** 63 * \brief Add a new Record to an Index hash 64 * 65 * \param index_hash Pointer to a lzma_index_hash structure 66 * \param unpadded_size Unpadded Size of a Block 67 * \param uncompressed_size Uncompressed Size of a Block 68 * 69 * \return Possible lzma_ret values: 70 * - LZMA_OK 71 * - LZMA_DATA_ERROR: Compressed or uncompressed size of the 72 * Stream or size of the Index field would grow too big. 73 * - LZMA_PROG_ERROR: Invalid arguments or this function is being 74 * used when lzma_index_hash_decode() has already been used. 75 */ 76 extern LZMA_API(lzma_ret) lzma_index_hash_append(lzma_index_hash *index_hash, 77 lzma_vli unpadded_size, lzma_vli uncompressed_size) 78 lzma_nothrow lzma_attr_warn_unused_result; 79 80 81 /** 82 * \brief Decode and validate the Index field 83 * 84 * After telling the sizes of all Blocks with lzma_index_hash_append(), 85 * the actual Index field is decoded with this function. Specifically, 86 * once decoding of the Index field has been started, no more Records 87 * can be added using lzma_index_hash_append(). 88 * 89 * This function doesn't use lzma_stream structure to pass the input data. 90 * Instead, the input buffer is specified using three arguments. This is 91 * because it matches better the internal APIs of liblzma. 92 * 93 * \param index_hash Pointer to a lzma_index_hash structure 94 * \param in Pointer to the beginning of the input buffer 95 * \param[out] in_pos in[*in_pos] is the next byte to process 96 * \param in_size in[in_size] is the first byte not to process 97 * 98 * \return Possible lzma_ret values: 99 * - LZMA_OK: So far good, but more input is needed. 100 * - LZMA_STREAM_END: Index decoded successfully and it matches 101 * the Records given with lzma_index_hash_append(). 102 * - LZMA_DATA_ERROR: Index is corrupt or doesn't match the 103 * information given with lzma_index_hash_append(). 104 * - LZMA_BUF_ERROR: Cannot progress because *in_pos >= in_size. 105 * - LZMA_PROG_ERROR 106 */ 107 extern LZMA_API(lzma_ret) lzma_index_hash_decode(lzma_index_hash *index_hash, 108 const uint8_t *in, size_t *in_pos, size_t in_size) 109 lzma_nothrow lzma_attr_warn_unused_result; 110 111 112 /** 113 * \brief Get the size of the Index field as bytes 114 * 115 * This is needed to verify the Backward Size field in the Stream Footer. 116 * 117 * \param index_hash Pointer to a lzma_index_hash structure 118 * 119 * \return Size of the Index field in bytes. 120 */ 121 extern LZMA_API(lzma_vli) lzma_index_hash_size( 122 const lzma_index_hash *index_hash) 123 lzma_nothrow lzma_attr_pure; 124