1 /** 2 * \file lzma/filter.h 3 * \brief Common filter related types and functions 4 */ 5 6 /* 7 * Author: Lasse Collin 8 * 9 * This file has been put into the public domain. 10 * You can do whatever you want with this file. 11 * 12 * See ../lzma.h for information about liblzma as a whole. 13 */ 14 15 #ifndef LZMA_H_INTERNAL 16 # error Never include this file directly. Use <lzma.h> instead. 17 #endif 18 19 20 /** 21 * \brief Maximum number of filters in a chain 22 * 23 * A filter chain can have 1-4 filters, of which three are allowed to change 24 * the size of the data. Usually only one or two filters are needed. 25 */ 26 #define LZMA_FILTERS_MAX 4 27 28 29 /** 30 * \brief Filter options 31 * 32 * This structure is used to pass Filter ID and a pointer filter's 33 * options to liblzma. A few functions work with a single lzma_filter 34 * structure, while most functions expect a filter chain. 35 * 36 * A filter chain is indicated with an array of lzma_filter structures. 37 * The array is terminated with .id = LZMA_VLI_UNKNOWN. Thus, the filter 38 * array must have LZMA_FILTERS_MAX + 1 elements (that is, five) to 39 * be able to hold any arbitrary filter chain. This is important when 40 * using lzma_block_header_decode() from block.h, because too small 41 * array would make liblzma write past the end of the filters array. 42 */ 43 typedef struct { 44 /** 45 * \brief Filter ID 46 * 47 * Use constants whose name begin with `LZMA_FILTER_' to specify 48 * different filters. In an array of lzma_filter structures, use 49 * LZMA_VLI_UNKNOWN to indicate end of filters. 50 * 51 * \note This is not an enum, because on some systems enums 52 * cannot be 64-bit. 53 */ 54 lzma_vli id; 55 56 /** 57 * \brief Pointer to filter-specific options structure 58 * 59 * If the filter doesn't need options, set this to NULL. If id is 60 * set to LZMA_VLI_UNKNOWN, options is ignored, and thus 61 * doesn't need be initialized. 62 */ 63 void *options; 64 65 } lzma_filter; 66 67 68 /** 69 * \brief Test if the given Filter ID is supported for encoding 70 * 71 * Return true if the give Filter ID is supported for encoding by this 72 * liblzma build. Otherwise false is returned. 73 * 74 * There is no way to list which filters are available in this particular 75 * liblzma version and build. It would be useless, because the application 76 * couldn't know what kind of options the filter would need. 77 */ 78 extern LZMA_API(lzma_bool) lzma_filter_encoder_is_supported(lzma_vli id) 79 lzma_nothrow lzma_attr_const; 80 81 82 /** 83 * \brief Test if the given Filter ID is supported for decoding 84 * 85 * Return true if the give Filter ID is supported for decoding by this 86 * liblzma build. Otherwise false is returned. 87 */ 88 extern LZMA_API(lzma_bool) lzma_filter_decoder_is_supported(lzma_vli id) 89 lzma_nothrow lzma_attr_const; 90 91 92 /** 93 * \brief Copy the filters array 94 * 95 * Copy the Filter IDs and filter-specific options from src to dest. 96 * Up to LZMA_FILTERS_MAX filters are copied, plus the terminating 97 * .id == LZMA_VLI_UNKNOWN. Thus, dest should have at least 98 * LZMA_FILTERS_MAX + 1 elements space unless the caller knows that 99 * src is smaller than that. 100 * 101 * Unless the filter-specific options is NULL, the Filter ID has to be 102 * supported by liblzma, because liblzma needs to know the size of every 103 * filter-specific options structure. The filter-specific options are not 104 * validated. If options is NULL, any unsupported Filter IDs are copied 105 * without returning an error. 106 * 107 * Old filter-specific options in dest are not freed, so dest doesn't 108 * need to be initialized by the caller in any way. 109 * 110 * If an error occurs, memory possibly already allocated by this function 111 * is always freed. 112 * 113 * \return - LZMA_OK 114 * - LZMA_MEM_ERROR 115 * - LZMA_OPTIONS_ERROR: Unsupported Filter ID and its options 116 * is not NULL. 117 * - LZMA_PROG_ERROR: src or dest is NULL. 118 */ 119 extern LZMA_API(lzma_ret) lzma_filters_copy(const lzma_filter *src, 120 lzma_filter *dest, lzma_allocator *allocator) lzma_nothrow; 121 122 123 /** 124 * \brief Calculate approximate memory requirements for raw encoder 125 * 126 * This function can be used to calculate the memory requirements for 127 * Block and Stream encoders too because Block and Stream encoders don't 128 * need significantly more memory than raw encoder. 129 * 130 * \param filters Array of filters terminated with 131 * .id == LZMA_VLI_UNKNOWN. 132 * 133 * \return Number of bytes of memory required for the given 134 * filter chain when encoding. 135 */ 136 extern LZMA_API(uint64_t) lzma_raw_encoder_memusage(const lzma_filter *filters) 137 lzma_nothrow lzma_attr_pure; 138 139 140 /** 141 * \brief Calculate approximate memory requirements for raw decoder 142 * 143 * This function can be used to calculate the memory requirements for 144 * Block and Stream decoders too because Block and Stream decoders don't 145 * need significantly more memory than raw decoder. 146 * 147 * \param filters Array of filters terminated with 148 * .id == LZMA_VLI_UNKNOWN. 149 * 150 * \return Number of bytes of memory required for the given 151 * filter chain when decoding. 152 */ 153 extern LZMA_API(uint64_t) lzma_raw_decoder_memusage(const lzma_filter *filters) 154 lzma_nothrow lzma_attr_pure; 155 156 157 /** 158 * \brief Initialize raw encoder 159 * 160 * This function may be useful when implementing custom file formats. 161 * 162 * \param strm Pointer to properly prepared lzma_stream 163 * \param filters Array of lzma_filter structures. The end of the 164 * array must be marked with .id = LZMA_VLI_UNKNOWN. 165 * 166 * The `action' with lzma_code() can be LZMA_RUN, LZMA_SYNC_FLUSH (if the 167 * filter chain supports it), or LZMA_FINISH. 168 * 169 * \return - LZMA_OK 170 * - LZMA_MEM_ERROR 171 * - LZMA_OPTIONS_ERROR 172 * - LZMA_PROG_ERROR 173 */ 174 extern LZMA_API(lzma_ret) lzma_raw_encoder( 175 lzma_stream *strm, const lzma_filter *filters) 176 lzma_nothrow lzma_attr_warn_unused_result; 177 178 179 /** 180 * \brief Initialize raw decoder 181 * 182 * The initialization of raw decoder goes similarly to raw encoder. 183 * 184 * The `action' with lzma_code() can be LZMA_RUN or LZMA_FINISH. Using 185 * LZMA_FINISH is not required, it is supported just for convenience. 186 * 187 * \return - LZMA_OK 188 * - LZMA_MEM_ERROR 189 * - LZMA_OPTIONS_ERROR 190 * - LZMA_PROG_ERROR 191 */ 192 extern LZMA_API(lzma_ret) lzma_raw_decoder( 193 lzma_stream *strm, const lzma_filter *filters) 194 lzma_nothrow lzma_attr_warn_unused_result; 195 196 197 /** 198 * \brief Update the filter chain in the encoder 199 * 200 * This function is for advanced users only. This function has two slightly 201 * different purposes: 202 * 203 * - After LZMA_FULL_FLUSH when using Stream encoder: Set a new filter 204 * chain, which will be used starting from the next Block. 205 * 206 * - After LZMA_SYNC_FLUSH using Raw, Block, or Stream encoder: Change 207 * the filter-specific options in the middle of encoding. The actual 208 * filters in the chain (Filter IDs) cannot be changed. In the future, 209 * it might become possible to change the filter options without 210 * using LZMA_SYNC_FLUSH. 211 * 212 * While rarely useful, this function may be called also when no data has 213 * been compressed yet. In that case, this function will behave as if 214 * LZMA_FULL_FLUSH (Stream encoder) or LZMA_SYNC_FLUSH (Raw or Block 215 * encoder) had been used right before calling this function. 216 * 217 * \return - LZMA_OK 218 * - LZMA_MEM_ERROR 219 * - LZMA_MEMLIMIT_ERROR 220 * - LZMA_OPTIONS_ERROR 221 * - LZMA_PROG_ERROR 222 */ 223 extern LZMA_API(lzma_ret) lzma_filters_update( 224 lzma_stream *strm, const lzma_filter *filters) lzma_nothrow; 225 226 227 /** 228 * \brief Single-call raw encoder 229 * 230 * \param filters Array of lzma_filter structures. The end of the 231 * array must be marked with .id = LZMA_VLI_UNKNOWN. 232 * \param allocator lzma_allocator for custom allocator functions. 233 * Set to NULL to use malloc() and free(). 234 * \param in Beginning of the input buffer 235 * \param in_size Size of the input buffer 236 * \param out Beginning of the output buffer 237 * \param out_pos The next byte will be written to out[*out_pos]. 238 * *out_pos is updated only if encoding succeeds. 239 * \param out_size Size of the out buffer; the first byte into 240 * which no data is written to is out[out_size]. 241 * 242 * \return - LZMA_OK: Encoding was successful. 243 * - LZMA_BUF_ERROR: Not enough output buffer space. 244 * - LZMA_OPTIONS_ERROR 245 * - LZMA_MEM_ERROR 246 * - LZMA_DATA_ERROR 247 * - LZMA_PROG_ERROR 248 * 249 * \note There is no function to calculate how big output buffer 250 * would surely be big enough. (lzma_stream_buffer_bound() 251 * works only for lzma_stream_buffer_encode(); raw encoder 252 * won't necessarily meet that bound.) 253 */ 254 extern LZMA_API(lzma_ret) lzma_raw_buffer_encode( 255 const lzma_filter *filters, lzma_allocator *allocator, 256 const uint8_t *in, size_t in_size, uint8_t *out, 257 size_t *out_pos, size_t out_size) lzma_nothrow; 258 259 260 /** 261 * \brief Single-call raw decoder 262 * 263 * \param filters Array of lzma_filter structures. The end of the 264 * array must be marked with .id = LZMA_VLI_UNKNOWN. 265 * \param allocator lzma_allocator for custom allocator functions. 266 * Set to NULL to use malloc() and free(). 267 * \param in Beginning of the input buffer 268 * \param in_pos The next byte will be read from in[*in_pos]. 269 * *in_pos is updated only if decoding succeeds. 270 * \param in_size Size of the input buffer; the first byte that 271 * won't be read is in[in_size]. 272 * \param out Beginning of the output buffer 273 * \param out_pos The next byte will be written to out[*out_pos]. 274 * *out_pos is updated only if encoding succeeds. 275 * \param out_size Size of the out buffer; the first byte into 276 * which no data is written to is out[out_size]. 277 */ 278 extern LZMA_API(lzma_ret) lzma_raw_buffer_decode( 279 const lzma_filter *filters, lzma_allocator *allocator, 280 const uint8_t *in, size_t *in_pos, size_t in_size, 281 uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow; 282 283 284 /** 285 * \brief Get the size of the Filter Properties field 286 * 287 * This function may be useful when implementing custom file formats 288 * using the raw encoder and decoder. 289 * 290 * \param size Pointer to uint32_t to hold the size of the properties 291 * \param filter Filter ID and options (the size of the properties may 292 * vary depending on the options) 293 * 294 * \return - LZMA_OK 295 * - LZMA_OPTIONS_ERROR 296 * - LZMA_PROG_ERROR 297 * 298 * \note This function validates the Filter ID, but does not 299 * necessarily validate the options. Thus, it is possible 300 * that this returns LZMA_OK while the following call to 301 * lzma_properties_encode() returns LZMA_OPTIONS_ERROR. 302 */ 303 extern LZMA_API(lzma_ret) lzma_properties_size( 304 uint32_t *size, const lzma_filter *filter) lzma_nothrow; 305 306 307 /** 308 * \brief Encode the Filter Properties field 309 * 310 * \param filter Filter ID and options 311 * \param props Buffer to hold the encoded options. The size of 312 * buffer must have been already determined with 313 * lzma_properties_size(). 314 * 315 * \return - LZMA_OK 316 * - LZMA_OPTIONS_ERROR 317 * - LZMA_PROG_ERROR 318 * 319 * \note Even this function won't validate more options than actually 320 * necessary. Thus, it is possible that encoding the properties 321 * succeeds but using the same options to initialize the encoder 322 * will fail. 323 * 324 * \note If lzma_properties_size() indicated that the size 325 * of the Filter Properties field is zero, calling 326 * lzma_properties_encode() is not required, but it 327 * won't do any harm either. 328 */ 329 extern LZMA_API(lzma_ret) lzma_properties_encode( 330 const lzma_filter *filter, uint8_t *props) lzma_nothrow; 331 332 333 /** 334 * \brief Decode the Filter Properties field 335 * 336 * \param filter filter->id must have been set to the correct 337 * Filter ID. filter->options doesn't need to be 338 * initialized (it's not freed by this function). The 339 * decoded options will be stored to filter->options. 340 * filter->options is set to NULL if there are no 341 * properties or if an error occurs. 342 * \param allocator Custom memory allocator used to allocate the 343 * options. Set to NULL to use the default malloc(), 344 * and in case of an error, also free(). 345 * \param props Input buffer containing the properties. 346 * \param props_size Size of the properties. This must be the exact 347 * size; giving too much or too little input will 348 * return LZMA_OPTIONS_ERROR. 349 * 350 * \return - LZMA_OK 351 * - LZMA_OPTIONS_ERROR 352 * - LZMA_MEM_ERROR 353 */ 354 extern LZMA_API(lzma_ret) lzma_properties_decode( 355 lzma_filter *filter, lzma_allocator *allocator, 356 const uint8_t *props, size_t props_size) lzma_nothrow; 357 358 359 /** 360 * \brief Calculate encoded size of a Filter Flags field 361 * 362 * Knowing the size of Filter Flags is useful to know when allocating 363 * memory to hold the encoded Filter Flags. 364 * 365 * \param size Pointer to integer to hold the calculated size 366 * \param filter Filter ID and associated options whose encoded 367 * size is to be calculated 368 * 369 * \return - LZMA_OK: *size set successfully. Note that this doesn't 370 * guarantee that filter->options is valid, thus 371 * lzma_filter_flags_encode() may still fail. 372 * - LZMA_OPTIONS_ERROR: Unknown Filter ID or unsupported options. 373 * - LZMA_PROG_ERROR: Invalid options 374 * 375 * \note If you need to calculate size of List of Filter Flags, 376 * you need to loop over every lzma_filter entry. 377 */ 378 extern LZMA_API(lzma_ret) lzma_filter_flags_size( 379 uint32_t *size, const lzma_filter *filter) 380 lzma_nothrow lzma_attr_warn_unused_result; 381 382 383 /** 384 * \brief Encode Filter Flags into given buffer 385 * 386 * In contrast to some functions, this doesn't allocate the needed buffer. 387 * This is due to how this function is used internally by liblzma. 388 * 389 * \param filter Filter ID and options to be encoded 390 * \param out Beginning of the output buffer 391 * \param out_pos out[*out_pos] is the next write position. This 392 * is updated by the encoder. 393 * \param out_size out[out_size] is the first byte to not write. 394 * 395 * \return - LZMA_OK: Encoding was successful. 396 * - LZMA_OPTIONS_ERROR: Invalid or unsupported options. 397 * - LZMA_PROG_ERROR: Invalid options or not enough output 398 * buffer space (you should have checked it with 399 * lzma_filter_flags_size()). 400 */ 401 extern LZMA_API(lzma_ret) lzma_filter_flags_encode(const lzma_filter *filter, 402 uint8_t *out, size_t *out_pos, size_t out_size) 403 lzma_nothrow lzma_attr_warn_unused_result; 404 405 406 /** 407 * \brief Decode Filter Flags from given buffer 408 * 409 * The decoded result is stored into *filter. The old value of 410 * filter->options is not free()d. 411 * 412 * \return - LZMA_OK 413 * - LZMA_OPTIONS_ERROR 414 * - LZMA_MEM_ERROR 415 * - LZMA_PROG_ERROR 416 */ 417 extern LZMA_API(lzma_ret) lzma_filter_flags_decode( 418 lzma_filter *filter, lzma_allocator *allocator, 419 const uint8_t *in, size_t *in_pos, size_t in_size) 420 lzma_nothrow lzma_attr_warn_unused_result; 421