3 * \brief Common filter related types and functions
9 * This file has been put into the public domain.
10 * You can do whatever you want with this file.
12 * See ../lzma.h for information about liblzma as a whole.
15 #ifndef LZMA_H_INTERNAL
16 # error Never include this file directly. Use <lzma.h> instead.
21 * \brief Maximum number of filters in a chain
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.
26 #define LZMA_FILTERS_MAX 4
30 * \brief Filter options
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.
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.
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.
51 * \note This is not an enum, because on some systems enums
57 * \brief Pointer to filter-specific options structure
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.
69 * \brief Test if the given Filter ID is supported for encoding
71 * Return true if the give Filter ID is supported for encoding by this
72 * liblzma build. Otherwise false is returned.
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.
78 extern LZMA_API(lzma_bool) lzma_filter_encoder_is_supported(lzma_vli id)
79 lzma_nothrow lzma_attr_const;
83 * \brief Test if the given Filter ID is supported for decoding
85 * Return true if the give Filter ID is supported for decoding by this
86 * liblzma build. Otherwise false is returned.
88 extern LZMA_API(lzma_bool) lzma_filter_decoder_is_supported(lzma_vli id)
89 lzma_nothrow lzma_attr_const;
93 * \brief Copy the filters array
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.
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.
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.
110 * If an error occurs, memory possibly already allocated by this function
115 * - LZMA_OPTIONS_ERROR: Unsupported Filter ID and its options
117 * - LZMA_PROG_ERROR: src or dest is NULL.
119 extern LZMA_API(lzma_ret) lzma_filters_copy(const lzma_filter *src,
120 lzma_filter *dest, lzma_allocator *allocator) lzma_nothrow;
124 * \brief Calculate approximate memory requirements for raw encoder
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.
130 * \param filters Array of filters terminated with
131 * .id == LZMA_VLI_UNKNOWN.
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.
138 extern LZMA_API(uint64_t) lzma_raw_encoder_memusage(const lzma_filter *filters)
139 lzma_nothrow lzma_attr_pure;
143 * \brief Calculate approximate memory requirements for raw decoder
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.
149 * \param filters Array of filters terminated with
150 * .id == LZMA_VLI_UNKNOWN.
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.
157 extern LZMA_API(uint64_t) lzma_raw_decoder_memusage(const lzma_filter *filters)
158 lzma_nothrow lzma_attr_pure;
162 * \brief Initialize raw encoder
164 * This function may be useful when implementing custom file formats.
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.
170 * The `action' with lzma_code() can be LZMA_RUN, LZMA_SYNC_FLUSH (if the
171 * filter chain supports it), or LZMA_FINISH.
175 * - LZMA_OPTIONS_ERROR
178 extern LZMA_API(lzma_ret) lzma_raw_encoder(
179 lzma_stream *strm, const lzma_filter *filters)
180 lzma_nothrow lzma_attr_warn_unused_result;
184 * \brief Initialize raw decoder
186 * The initialization of raw decoder goes similarly to raw encoder.
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.
193 * - LZMA_OPTIONS_ERROR
196 extern LZMA_API(lzma_ret) lzma_raw_decoder(
197 lzma_stream *strm, const lzma_filter *filters)
198 lzma_nothrow lzma_attr_warn_unused_result;
202 * \brief Update the filter chain in the encoder
204 * This function is for advanced users only. This function has two slightly
205 * different purposes:
207 * - After LZMA_FULL_FLUSH when using Stream encoder: Set a new filter
208 * chain, which will be used starting from the next Block.
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.
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.
223 * - LZMA_MEMLIMIT_ERROR
224 * - LZMA_OPTIONS_ERROR
227 extern LZMA_API(lzma_ret) lzma_filters_update(
228 lzma_stream *strm, const lzma_filter *filters) lzma_nothrow;
232 * \brief Single-call raw encoder
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].
246 * \return - LZMA_OK: Encoding was successful.
247 * - LZMA_BUF_ERROR: Not enough output buffer space.
248 * - LZMA_OPTIONS_ERROR
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.)
258 extern 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;
265 * \brief Single-call raw decoder
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].
282 extern 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;
289 * \brief Get the size of the Filter Properties field
291 * This function may be useful when implementing custom file formats
292 * using the raw encoder and decoder.
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)
299 * - LZMA_OPTIONS_ERROR
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.
307 extern LZMA_API(lzma_ret) lzma_properties_size(
308 uint32_t *size, const lzma_filter *filter) lzma_nothrow;
312 * \brief Encode the Filter Properties field
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().
320 * - LZMA_OPTIONS_ERROR
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
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.
333 extern LZMA_API(lzma_ret) lzma_properties_encode(
334 const lzma_filter *filter, uint8_t *props) lzma_nothrow;
338 * \brief Decode the Filter Properties field
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.
355 * - LZMA_OPTIONS_ERROR
358 extern 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;
364 * \brief Calculate encoded size of a Filter Flags field
366 * Knowing the size of Filter Flags is useful to know when allocating
367 * memory to hold the encoded Filter Flags.
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
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
379 * \note If you need to calculate size of List of Filter Flags,
380 * you need to loop over every lzma_filter entry.
382 extern LZMA_API(lzma_ret) lzma_filter_flags_size(
383 uint32_t *size, const lzma_filter *filter)
384 lzma_nothrow lzma_attr_warn_unused_result;
388 * \brief Encode Filter Flags into given buffer
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.
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.
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()).
405 extern 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;
411 * \brief Decode Filter Flags from given buffer
413 * The decoded result is stored into *filter. The old value of
414 * filter->options is not free()d.
417 * - LZMA_OPTIONS_ERROR
421 extern 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;