filter.h revision 256281
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 */ 43typedef 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 */ 78extern 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 */ 88extern 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 */ 119extern 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. If an error occurs, 135 * for example due to unsupported filter chain, 136 * UINT64_MAX is returned. 137 */ 138extern LZMA_API(uint64_t) lzma_raw_encoder_memusage(const lzma_filter *filters) 139 lzma_nothrow lzma_attr_pure; 140 141 142/** 143 * \brief Calculate approximate memory requirements for raw decoder 144 * 145 * This function can be used to calculate the memory requirements for 146 * Block and Stream decoders too because Block and Stream decoders don't 147 * need significantly more memory than raw decoder. 148 * 149 * \param filters Array of filters terminated with 150 * .id == LZMA_VLI_UNKNOWN. 151 * 152 * \return Number of bytes of memory required for the given 153 * filter chain when decoding. If an error occurs, 154 * for example due to unsupported filter chain, 155 * UINT64_MAX is returned. 156 */ 157extern LZMA_API(uint64_t) lzma_raw_decoder_memusage(const lzma_filter *filters) 158 lzma_nothrow lzma_attr_pure; 159 160 161/** 162 * \brief Initialize raw encoder 163 * 164 * This function may be useful when implementing custom file formats. 165 * 166 * \param strm Pointer to properly prepared lzma_stream 167 * \param filters Array of lzma_filter structures. The end of the 168 * array must be marked with .id = LZMA_VLI_UNKNOWN. 169 * 170 * The `action' with lzma_code() can be LZMA_RUN, LZMA_SYNC_FLUSH (if the 171 * filter chain supports it), or LZMA_FINISH. 172 * 173 * \return - LZMA_OK 174 * - LZMA_MEM_ERROR 175 * - LZMA_OPTIONS_ERROR 176 * - LZMA_PROG_ERROR 177 */ 178extern LZMA_API(lzma_ret) lzma_raw_encoder( 179 lzma_stream *strm, const lzma_filter *filters) 180 lzma_nothrow lzma_attr_warn_unused_result; 181 182 183/** 184 * \brief Initialize raw decoder 185 * 186 * The initialization of raw decoder goes similarly to raw encoder. 187 * 188 * The `action' with lzma_code() can be LZMA_RUN or LZMA_FINISH. Using 189 * LZMA_FINISH is not required, it is supported just for convenience. 190 * 191 * \return - LZMA_OK 192 * - LZMA_MEM_ERROR 193 * - LZMA_OPTIONS_ERROR 194 * - LZMA_PROG_ERROR 195 */ 196extern LZMA_API(lzma_ret) lzma_raw_decoder( 197 lzma_stream *strm, const lzma_filter *filters) 198 lzma_nothrow lzma_attr_warn_unused_result; 199 200 201/** 202 * \brief Update the filter chain in the encoder 203 * 204 * This function is for advanced users only. This function has two slightly 205 * different purposes: 206 * 207 * - After LZMA_FULL_FLUSH when using Stream encoder: Set a new filter 208 * chain, which will be used starting from the next Block. 209 * 210 * - After LZMA_SYNC_FLUSH using Raw, Block, or Stream encoder: Change 211 * the filter-specific options in the middle of encoding. The actual 212 * filters in the chain (Filter IDs) cannot be changed. In the future, 213 * it might become possible to change the filter options without 214 * using LZMA_SYNC_FLUSH. 215 * 216 * While rarely useful, this function may be called also when no data has 217 * been compressed yet. In that case, this function will behave as if 218 * LZMA_FULL_FLUSH (Stream encoder) or LZMA_SYNC_FLUSH (Raw or Block 219 * encoder) had been used right before calling this function. 220 * 221 * \return - LZMA_OK 222 * - LZMA_MEM_ERROR 223 * - LZMA_MEMLIMIT_ERROR 224 * - LZMA_OPTIONS_ERROR 225 * - LZMA_PROG_ERROR 226 */ 227extern LZMA_API(lzma_ret) lzma_filters_update( 228 lzma_stream *strm, const lzma_filter *filters) lzma_nothrow; 229 230 231/** 232 * \brief Single-call raw encoder 233 * 234 * \param filters Array of lzma_filter structures. The end of the 235 * array must be marked with .id = LZMA_VLI_UNKNOWN. 236 * \param allocator lzma_allocator for custom allocator functions. 237 * Set to NULL to use malloc() and free(). 238 * \param in Beginning of the input buffer 239 * \param in_size Size of the input buffer 240 * \param out Beginning of the output buffer 241 * \param out_pos The next byte will be written to out[*out_pos]. 242 * *out_pos is updated only if encoding succeeds. 243 * \param out_size Size of the out buffer; the first byte into 244 * which no data is written to is out[out_size]. 245 * 246 * \return - LZMA_OK: Encoding was successful. 247 * - LZMA_BUF_ERROR: Not enough output buffer space. 248 * - LZMA_OPTIONS_ERROR 249 * - LZMA_MEM_ERROR 250 * - LZMA_DATA_ERROR 251 * - LZMA_PROG_ERROR 252 * 253 * \note There is no function to calculate how big output buffer 254 * would surely be big enough. (lzma_stream_buffer_bound() 255 * works only for lzma_stream_buffer_encode(); raw encoder 256 * won't necessarily meet that bound.) 257 */ 258extern LZMA_API(lzma_ret) lzma_raw_buffer_encode( 259 const lzma_filter *filters, lzma_allocator *allocator, 260 const uint8_t *in, size_t in_size, uint8_t *out, 261 size_t *out_pos, size_t out_size) lzma_nothrow; 262 263 264/** 265 * \brief Single-call raw decoder 266 * 267 * \param filters Array of lzma_filter structures. The end of the 268 * array must be marked with .id = LZMA_VLI_UNKNOWN. 269 * \param allocator lzma_allocator for custom allocator functions. 270 * Set to NULL to use malloc() and free(). 271 * \param in Beginning of the input buffer 272 * \param in_pos The next byte will be read from in[*in_pos]. 273 * *in_pos is updated only if decoding succeeds. 274 * \param in_size Size of the input buffer; the first byte that 275 * won't be read is in[in_size]. 276 * \param out Beginning of the output buffer 277 * \param out_pos The next byte will be written to out[*out_pos]. 278 * *out_pos is updated only if encoding succeeds. 279 * \param out_size Size of the out buffer; the first byte into 280 * which no data is written to is out[out_size]. 281 */ 282extern LZMA_API(lzma_ret) lzma_raw_buffer_decode( 283 const lzma_filter *filters, lzma_allocator *allocator, 284 const uint8_t *in, size_t *in_pos, size_t in_size, 285 uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow; 286 287 288/** 289 * \brief Get the size of the Filter Properties field 290 * 291 * This function may be useful when implementing custom file formats 292 * using the raw encoder and decoder. 293 * 294 * \param size Pointer to uint32_t to hold the size of the properties 295 * \param filter Filter ID and options (the size of the properties may 296 * vary depending on the options) 297 * 298 * \return - LZMA_OK 299 * - LZMA_OPTIONS_ERROR 300 * - LZMA_PROG_ERROR 301 * 302 * \note This function validates the Filter ID, but does not 303 * necessarily validate the options. Thus, it is possible 304 * that this returns LZMA_OK while the following call to 305 * lzma_properties_encode() returns LZMA_OPTIONS_ERROR. 306 */ 307extern LZMA_API(lzma_ret) lzma_properties_size( 308 uint32_t *size, const lzma_filter *filter) lzma_nothrow; 309 310 311/** 312 * \brief Encode the Filter Properties field 313 * 314 * \param filter Filter ID and options 315 * \param props Buffer to hold the encoded options. The size of 316 * buffer must have been already determined with 317 * lzma_properties_size(). 318 * 319 * \return - LZMA_OK 320 * - LZMA_OPTIONS_ERROR 321 * - LZMA_PROG_ERROR 322 * 323 * \note Even this function won't validate more options than actually 324 * necessary. Thus, it is possible that encoding the properties 325 * succeeds but using the same options to initialize the encoder 326 * will fail. 327 * 328 * \note If lzma_properties_size() indicated that the size 329 * of the Filter Properties field is zero, calling 330 * lzma_properties_encode() is not required, but it 331 * won't do any harm either. 332 */ 333extern LZMA_API(lzma_ret) lzma_properties_encode( 334 const lzma_filter *filter, uint8_t *props) lzma_nothrow; 335 336 337/** 338 * \brief Decode the Filter Properties field 339 * 340 * \param filter filter->id must have been set to the correct 341 * Filter ID. filter->options doesn't need to be 342 * initialized (it's not freed by this function). The 343 * decoded options will be stored to filter->options. 344 * filter->options is set to NULL if there are no 345 * properties or if an error occurs. 346 * \param allocator Custom memory allocator used to allocate the 347 * options. Set to NULL to use the default malloc(), 348 * and in case of an error, also free(). 349 * \param props Input buffer containing the properties. 350 * \param props_size Size of the properties. This must be the exact 351 * size; giving too much or too little input will 352 * return LZMA_OPTIONS_ERROR. 353 * 354 * \return - LZMA_OK 355 * - LZMA_OPTIONS_ERROR 356 * - LZMA_MEM_ERROR 357 */ 358extern LZMA_API(lzma_ret) lzma_properties_decode( 359 lzma_filter *filter, lzma_allocator *allocator, 360 const uint8_t *props, size_t props_size) lzma_nothrow; 361 362 363/** 364 * \brief Calculate encoded size of a Filter Flags field 365 * 366 * Knowing the size of Filter Flags is useful to know when allocating 367 * memory to hold the encoded Filter Flags. 368 * 369 * \param size Pointer to integer to hold the calculated size 370 * \param filter Filter ID and associated options whose encoded 371 * size is to be calculated 372 * 373 * \return - LZMA_OK: *size set successfully. Note that this doesn't 374 * guarantee that filter->options is valid, thus 375 * lzma_filter_flags_encode() may still fail. 376 * - LZMA_OPTIONS_ERROR: Unknown Filter ID or unsupported options. 377 * - LZMA_PROG_ERROR: Invalid options 378 * 379 * \note If you need to calculate size of List of Filter Flags, 380 * you need to loop over every lzma_filter entry. 381 */ 382extern LZMA_API(lzma_ret) lzma_filter_flags_size( 383 uint32_t *size, const lzma_filter *filter) 384 lzma_nothrow lzma_attr_warn_unused_result; 385 386 387/** 388 * \brief Encode Filter Flags into given buffer 389 * 390 * In contrast to some functions, this doesn't allocate the needed buffer. 391 * This is due to how this function is used internally by liblzma. 392 * 393 * \param filter Filter ID and options to be encoded 394 * \param out Beginning of the output buffer 395 * \param out_pos out[*out_pos] is the next write position. This 396 * is updated by the encoder. 397 * \param out_size out[out_size] is the first byte to not write. 398 * 399 * \return - LZMA_OK: Encoding was successful. 400 * - LZMA_OPTIONS_ERROR: Invalid or unsupported options. 401 * - LZMA_PROG_ERROR: Invalid options or not enough output 402 * buffer space (you should have checked it with 403 * lzma_filter_flags_size()). 404 */ 405extern LZMA_API(lzma_ret) lzma_filter_flags_encode(const lzma_filter *filter, 406 uint8_t *out, size_t *out_pos, size_t out_size) 407 lzma_nothrow lzma_attr_warn_unused_result; 408 409 410/** 411 * \brief Decode Filter Flags from given buffer 412 * 413 * The decoded result is stored into *filter. The old value of 414 * filter->options is not free()d. 415 * 416 * \return - LZMA_OK 417 * - LZMA_OPTIONS_ERROR 418 * - LZMA_MEM_ERROR 419 * - LZMA_PROG_ERROR 420 */ 421extern LZMA_API(lzma_ret) lzma_filter_flags_decode( 422 lzma_filter *filter, lzma_allocator *allocator, 423 const uint8_t *in, size_t *in_pos, size_t in_size) 424 lzma_nothrow lzma_attr_warn_unused_result; 425