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Diffstat (limited to 'src/liblzma/api/lzma/filter.h')
| -rw-r--r-- | src/liblzma/api/lzma/filter.h | 770 |
1 files changed, 770 insertions, 0 deletions
diff --git a/src/liblzma/api/lzma/filter.h b/src/liblzma/api/lzma/filter.h new file mode 100644 index 0000000..1d887b4 --- /dev/null +++ b/src/liblzma/api/lzma/filter.h @@ -0,0 +1,770 @@ +/** + * \file lzma/filter.h + * \brief Common filter related types and functions + * \note Never include this file directly. Use <lzma.h> instead. + */ + +/* + * Author: Lasse Collin + * + * This file has been put into the public domain. + * You can do whatever you want with this file. + */ + +#ifndef LZMA_H_INTERNAL +# error Never include this file directly. Use <lzma.h> instead. +#endif + + +/** + * \brief Maximum number of filters in a chain + * + * A filter chain can have 1-4 filters, of which three are allowed to change + * the size of the data. Usually only one or two filters are needed. + */ +#define LZMA_FILTERS_MAX 4 + + +/** + * \brief Filter options + * + * This structure is used to pass a Filter ID and a pointer to the filter's + * options to liblzma. A few functions work with a single lzma_filter + * structure, while most functions expect a filter chain. + * + * A filter chain is indicated with an array of lzma_filter structures. + * The array is terminated with .id = LZMA_VLI_UNKNOWN. Thus, the filter + * array must have LZMA_FILTERS_MAX + 1 elements (that is, five) to + * be able to hold any arbitrary filter chain. This is important when + * using lzma_block_header_decode() from block.h, because a filter array + * that is too small would make liblzma write past the end of the array. + */ +typedef struct { + /** + * \brief Filter ID + * + * Use constants whose name begin with `LZMA_FILTER_' to specify + * different filters. In an array of lzma_filter structures, use + * LZMA_VLI_UNKNOWN to indicate end of filters. + * + * \note This is not an enum, because on some systems enums + * cannot be 64-bit. + */ + lzma_vli id; + + /** + * \brief Pointer to filter-specific options structure + * + * If the filter doesn't need options, set this to NULL. If id is + * set to LZMA_VLI_UNKNOWN, options is ignored, and thus + * doesn't need be initialized. + */ + void *options; + +} lzma_filter; + + +/** + * \brief Test if the given Filter ID is supported for encoding + * + * \param id Filter ID + * + * \return lzma_bool: + * - true if the Filter ID is supported for encoding by this + * liblzma build. + * - false otherwise. + */ +extern LZMA_API(lzma_bool) lzma_filter_encoder_is_supported(lzma_vli id) + lzma_nothrow lzma_attr_const; + + +/** + * \brief Test if the given Filter ID is supported for decoding + * + * \param id Filter ID + * + * \return lzma_bool: + * - true if the Filter ID is supported for decoding by this + * liblzma build. + * - false otherwise. + */ +extern LZMA_API(lzma_bool) lzma_filter_decoder_is_supported(lzma_vli id) + lzma_nothrow lzma_attr_const; + + +/** + * \brief Copy the filters array + * + * Copy the Filter IDs and filter-specific options from src to dest. + * Up to LZMA_FILTERS_MAX filters are copied, plus the terminating + * .id == LZMA_VLI_UNKNOWN. Thus, dest should have at least + * LZMA_FILTERS_MAX + 1 elements space unless the caller knows that + * src is smaller than that. + * + * Unless the filter-specific options is NULL, the Filter ID has to be + * supported by liblzma, because liblzma needs to know the size of every + * filter-specific options structure. The filter-specific options are not + * validated. If options is NULL, any unsupported Filter IDs are copied + * without returning an error. + * + * Old filter-specific options in dest are not freed, so dest doesn't + * need to be initialized by the caller in any way. + * + * If an error occurs, memory possibly already allocated by this function + * is always freed. liblzma versions older than 5.2.7 may modify the dest + * array and leave its contents in an undefined state if an error occurs. + * liblzma 5.2.7 and newer only modify the dest array when returning LZMA_OK. + * + * \param src Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * \param[out] dest Destination filter array + * \param allocator lzma_allocator for custom allocator functions. + * Set to NULL to use malloc() and free(). + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_MEM_ERROR + * - LZMA_OPTIONS_ERROR: Unsupported Filter ID and its options + * is not NULL. + * - LZMA_PROG_ERROR: src or dest is NULL. + */ +extern LZMA_API(lzma_ret) lzma_filters_copy( + const lzma_filter *src, lzma_filter *dest, + const lzma_allocator *allocator) + lzma_nothrow lzma_attr_warn_unused_result; + + +/** + * \brief Free the options in the array of lzma_filter structures + * + * This frees the filter chain options. The filters array itself is not freed. + * + * The filters array must have at most LZMA_FILTERS_MAX + 1 elements + * including the terminating element which must have .id = LZMA_VLI_UNKNOWN. + * For all elements before the terminating element: + * - options will be freed using the given lzma_allocator or, + * if allocator is NULL, using free(). + * - options will be set to NULL. + * - id will be set to LZMA_VLI_UNKNOWN. + * + * If filters is NULL, this does nothing. Again, this never frees the + * filters array itself. + * + * \param filters Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * \param allocator lzma_allocator for custom allocator functions. + * Set to NULL to use malloc() and free(). + */ +extern LZMA_API(void) lzma_filters_free( + lzma_filter *filters, const lzma_allocator *allocator) + lzma_nothrow; + + +/** + * \brief Calculate approximate memory requirements for raw encoder + * + * This function can be used to calculate the memory requirements for + * Block and Stream encoders too because Block and Stream encoders don't + * need significantly more memory than raw encoder. + * + * \param filters Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * + * \return Number of bytes of memory required for the given + * filter chain when encoding or UINT64_MAX on error. + */ +extern LZMA_API(uint64_t) lzma_raw_encoder_memusage(const lzma_filter *filters) + lzma_nothrow lzma_attr_pure; + + +/** + * \brief Calculate approximate memory requirements for raw decoder + * + * This function can be used to calculate the memory requirements for + * Block and Stream decoders too because Block and Stream decoders don't + * need significantly more memory than raw decoder. + * + * \param filters Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * + * \return Number of bytes of memory required for the given + * filter chain when decoding or UINT64_MAX on error. + */ +extern LZMA_API(uint64_t) lzma_raw_decoder_memusage(const lzma_filter *filters) + lzma_nothrow lzma_attr_pure; + + +/** + * \brief Initialize raw encoder + * + * This function may be useful when implementing custom file formats. + * + * The `action' with lzma_code() can be LZMA_RUN, LZMA_SYNC_FLUSH (if the + * filter chain supports it), or LZMA_FINISH. + * + * \param strm Pointer to lzma_stream that is at least + * initialized with LZMA_STREAM_INIT. + * \param filters Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_MEM_ERROR + * - LZMA_OPTIONS_ERROR + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_raw_encoder( + lzma_stream *strm, const lzma_filter *filters) + lzma_nothrow lzma_attr_warn_unused_result; + + +/** + * \brief Initialize raw decoder + * + * The initialization of raw decoder goes similarly to raw encoder. + * + * The `action' with lzma_code() can be LZMA_RUN or LZMA_FINISH. Using + * LZMA_FINISH is not required, it is supported just for convenience. + * + * \param strm Pointer to lzma_stream that is at least + * initialized with LZMA_STREAM_INIT. + * \param filters Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_MEM_ERROR + * - LZMA_OPTIONS_ERROR + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_raw_decoder( + lzma_stream *strm, const lzma_filter *filters) + lzma_nothrow lzma_attr_warn_unused_result; + + +/** + * \brief Update the filter chain in the encoder + * + * This function may be called after lzma_code() has returned LZMA_STREAM_END + * when LZMA_FULL_BARRIER, LZMA_FULL_FLUSH, or LZMA_SYNC_FLUSH was used: + * + * - After LZMA_FULL_BARRIER or LZMA_FULL_FLUSH: Single-threaded .xz Stream + * encoder (lzma_stream_encoder()) and (since liblzma 5.4.0) multi-threaded + * Stream encoder (lzma_stream_encoder_mt()) allow setting a new filter + * chain to be used for the next Block(s). + * + * - After LZMA_SYNC_FLUSH: Raw encoder (lzma_raw_encoder()), + * Block encoder (lzma_block_encoder()), and single-threaded .xz Stream + * encoder (lzma_stream_encoder()) allow changing certain filter-specific + * options in the middle of encoding. The actual filters in the chain + * (Filter IDs) must not be changed! Currently only the lc, lp, and pb + * options of LZMA2 (not LZMA1) can be changed this way. + * + * - In the future some filters might allow changing some of their options + * without any barrier or flushing but currently such filters don't exist. + * + * This function may also be called when no data has been compressed yet + * although this is rarely useful. In that case, this function will behave + * as if LZMA_FULL_FLUSH (Stream encoders) or LZMA_SYNC_FLUSH (Raw or Block + * encoder) had been used right before calling this function. + * + * \param strm Pointer to lzma_stream that is at least + * initialized with LZMA_STREAM_INIT. + * \param filters Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_MEM_ERROR + * - LZMA_MEMLIMIT_ERROR + * - LZMA_OPTIONS_ERROR + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_filters_update( + lzma_stream *strm, const lzma_filter *filters) lzma_nothrow; + + +/** + * \brief Single-call raw encoder + * + * \note There is no function to calculate how big output buffer + * would surely be big enough. (lzma_stream_buffer_bound() + * works only for lzma_stream_buffer_encode(); raw encoder + * won't necessarily meet that bound.) + * + * \param filters Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * \param allocator lzma_allocator for custom allocator functions. + * Set to NULL to use malloc() and free(). + * \param in Beginning of the input buffer + * \param in_size Size of the input buffer + * \param[out] out Beginning of the output buffer + * \param[out] out_pos The next byte will be written to out[*out_pos]. + * *out_pos is updated only if encoding succeeds. + * \param out_size Size of the out buffer; the first byte into + * which no data is written to is out[out_size]. + * + * \return Possible lzma_ret values: + * - LZMA_OK: Encoding was successful. + * - LZMA_BUF_ERROR: Not enough output buffer space. + * - LZMA_OPTIONS_ERROR + * - LZMA_MEM_ERROR + * - LZMA_DATA_ERROR + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_raw_buffer_encode( + const lzma_filter *filters, const lzma_allocator *allocator, + const uint8_t *in, size_t in_size, uint8_t *out, + size_t *out_pos, size_t out_size) lzma_nothrow; + + +/** + * \brief Single-call raw decoder + * + * \param filters Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * \param allocator lzma_allocator for custom allocator functions. + * Set to NULL to use malloc() and free(). + * \param in Beginning of the input buffer + * \param in_pos The next byte will be read from in[*in_pos]. + * *in_pos is updated only if decoding succeeds. + * \param in_size Size of the input buffer; the first byte that + * won't be read is in[in_size]. + * \param[out] out Beginning of the output buffer + * \param[out] out_pos The next byte will be written to out[*out_pos]. + * *out_pos is updated only if encoding succeeds. + * \param out_size Size of the out buffer; the first byte into + * which no data is written to is out[out_size]. + * + * \return Possible lzma_ret values: + * - LZMA_OK: Decoding was successful. + * - LZMA_BUF_ERROR: Not enough output buffer space. + * - LZMA_OPTIONS_ERROR + * - LZMA_MEM_ERROR + * - LZMA_DATA_ERROR + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_raw_buffer_decode( + const lzma_filter *filters, const lzma_allocator *allocator, + const uint8_t *in, size_t *in_pos, size_t in_size, + uint8_t *out, size_t *out_pos, size_t out_size) lzma_nothrow; + + +/** + * \brief Get the size of the Filter Properties field + * + * This function may be useful when implementing custom file formats + * using the raw encoder and decoder. + * + * \note This function validates the Filter ID, but does not + * necessarily validate the options. Thus, it is possible + * that this returns LZMA_OK while the following call to + * lzma_properties_encode() returns LZMA_OPTIONS_ERROR. + * + * \param[out] size Pointer to uint32_t to hold the size of the properties + * \param filter Filter ID and options (the size of the properties may + * vary depending on the options) + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_OPTIONS_ERROR + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_properties_size( + uint32_t *size, const lzma_filter *filter) lzma_nothrow; + + +/** + * \brief Encode the Filter Properties field + * + * \note Even this function won't validate more options than actually + * necessary. Thus, it is possible that encoding the properties + * succeeds but using the same options to initialize the encoder + * will fail. + * + * \note If lzma_properties_size() indicated that the size + * of the Filter Properties field is zero, calling + * lzma_properties_encode() is not required, but it + * won't do any harm either. + * + * \param filter Filter ID and options + * \param[out] props Buffer to hold the encoded options. The size of + * the buffer must have been already determined with + * lzma_properties_size(). + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_properties_encode( + const lzma_filter *filter, uint8_t *props) lzma_nothrow; + + +/** + * \brief Decode the Filter Properties field + * + * \param filter filter->id must have been set to the correct + * Filter ID. filter->options doesn't need to be + * initialized (it's not freed by this function). The + * decoded options will be stored in filter->options; + * it's application's responsibility to free it when + * appropriate. filter->options is set to NULL if + * there are no properties or if an error occurs. + * \param allocator lzma_allocator for custom allocator functions. + * Set to NULL to use malloc() and free(). + * and in case of an error, also free(). + * \param props Input buffer containing the properties. + * \param props_size Size of the properties. This must be the exact + * size; giving too much or too little input will + * return LZMA_OPTIONS_ERROR. + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_OPTIONS_ERROR + * - LZMA_MEM_ERROR + */ +extern LZMA_API(lzma_ret) lzma_properties_decode( + lzma_filter *filter, const lzma_allocator *allocator, + const uint8_t *props, size_t props_size) lzma_nothrow; + + +/** + * \brief Calculate encoded size of a Filter Flags field + * + * Knowing the size of Filter Flags is useful to know when allocating + * memory to hold the encoded Filter Flags. + * + * \note If you need to calculate size of List of Filter Flags, + * you need to loop over every lzma_filter entry. + * + * \param[out] size Pointer to integer to hold the calculated size + * \param filter Filter ID and associated options whose encoded + * size is to be calculated + * + * \return Possible lzma_ret values: + * - LZMA_OK: *size set successfully. Note that this doesn't + * guarantee that filter->options is valid, thus + * lzma_filter_flags_encode() may still fail. + * - LZMA_OPTIONS_ERROR: Unknown Filter ID or unsupported options. + * - LZMA_PROG_ERROR: Invalid options + */ +extern LZMA_API(lzma_ret) lzma_filter_flags_size( + uint32_t *size, const lzma_filter *filter) + lzma_nothrow lzma_attr_warn_unused_result; + + +/** + * \brief Encode Filter Flags into given buffer + * + * In contrast to some functions, this doesn't allocate the needed buffer. + * This is due to how this function is used internally by liblzma. + * + * \param filter Filter ID and options to be encoded + * \param[out] out Beginning of the output buffer + * \param[out] out_pos out[*out_pos] is the next write position. This + * is updated by the encoder. + * \param out_size out[out_size] is the first byte to not write. + * + * \return Possible lzma_ret values: + * - LZMA_OK: Encoding was successful. + * - LZMA_OPTIONS_ERROR: Invalid or unsupported options. + * - LZMA_PROG_ERROR: Invalid options or not enough output + * buffer space (you should have checked it with + * lzma_filter_flags_size()). + */ +extern LZMA_API(lzma_ret) lzma_filter_flags_encode(const lzma_filter *filter, + uint8_t *out, size_t *out_pos, size_t out_size) + lzma_nothrow lzma_attr_warn_unused_result; + + +/** + * \brief Decode Filter Flags from given buffer + * + * The decoded result is stored into *filter. The old value of + * filter->options is not free()d. If anything other than LZMA_OK + * is returned, filter->options is set to NULL. + * + * \param[out] filter Destination filter. The decoded Filter ID will + * be stored in filter->id. If options are needed + * they will be allocated and the pointer will be + * stored in filter->options. + * \param allocator lzma_allocator for custom allocator functions. + * Set to NULL to use malloc() and free(). + * \param in Beginning of the input buffer + * \param[out] in_pos The next byte will be read from in[*in_pos]. + * *in_pos is updated only if decoding succeeds. + * \param in_size Size of the input buffer; the first byte that + * won't be read is in[in_size]. + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_OPTIONS_ERROR + * - LZMA_MEM_ERROR + * - LZMA_DATA_ERROR + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_filter_flags_decode( + lzma_filter *filter, const lzma_allocator *allocator, + const uint8_t *in, size_t *in_pos, size_t in_size) + lzma_nothrow lzma_attr_warn_unused_result; + + +/*********** + * Strings * + ***********/ + +/** + * \brief Allow or show all filters + * + * By default only the filters supported in the .xz format are accept by + * lzma_str_to_filters() or shown by lzma_str_list_filters(). + */ +#define LZMA_STR_ALL_FILTERS UINT32_C(0x01) + + +/** + * \brief Do not validate the filter chain in lzma_str_to_filters() + * + * By default lzma_str_to_filters() can return an error if the filter chain + * as a whole isn't usable in the .xz format or in the raw encoder or decoder. + * With this flag, this validation is skipped. This flag doesn't affect the + * handling of the individual filter options. To allow non-.xz filters also + * LZMA_STR_ALL_FILTERS is needed. + */ +#define LZMA_STR_NO_VALIDATION UINT32_C(0x02) + + +/** + * \brief Stringify encoder options + * + * Show the filter-specific options that the encoder will use. + * This may be useful for verbose diagnostic messages. + * + * Note that if options were decoded from .xz headers then the encoder options + * may be undefined. This flag shouldn't be used in such a situation. + */ +#define LZMA_STR_ENCODER UINT32_C(0x10) + + +/** + * \brief Stringify decoder options + * + * Show the filter-specific options that the decoder will use. + * This may be useful for showing what filter options were decoded + * from file headers. + */ +#define LZMA_STR_DECODER UINT32_C(0x20) + + +/** + * \brief Produce xz-compatible getopt_long() syntax + * + * That is, "delta:dist=2 lzma2:dict=4MiB,pb=1,lp=1" becomes + * "--delta=dist=2 --lzma2=dict=4MiB,pb=1,lp=1". + * + * This syntax is compatible with xz 5.0.0 as long as the filters and + * their options are supported too. + */ +#define LZMA_STR_GETOPT_LONG UINT32_C(0x40) + + +/** + * \brief Use two dashes "--" instead of a space to separate filters + * + * That is, "delta:dist=2 lzma2:pb=1,lp=1" becomes + * "delta:dist=2--lzma2:pb=1,lp=1". This looks slightly odd but this + * kind of strings should be usable on the command line without quoting. + * However, it is possible that future versions with new filter options + * might produce strings that require shell quoting anyway as the exact + * set of possible characters isn't frozen for now. + * + * It is guaranteed that the single quote (') will never be used in + * filter chain strings (even if LZMA_STR_NO_SPACES isn't used). + */ +#define LZMA_STR_NO_SPACES UINT32_C(0x80) + + +/** + * \brief Convert a string to a filter chain + * + * This tries to make it easier to write applications that allow users + * to set custom compression options. This only handles the filter + * configuration (including presets) but not the number of threads, + * block size, check type, or memory limits. + * + * The input string can be either a preset or a filter chain. Presets + * begin with a digit 0-9 and may be followed by zero or more flags + * which are lower-case letters. Currently only "e" is supported, matching + * LZMA_PRESET_EXTREME. For partial xz command line syntax compatibility, + * a preset string may start with a single dash "-". + * + * A filter chain consists of one or more "filtername:opt1=value1,opt2=value2" + * strings separated by one or more spaces. Leading and trailing spaces are + * ignored. All names and values must be lower-case. Extra commas in the + * option list are ignored. The order of filters is significant: when + * encoding, the uncompressed input data goes to the leftmost filter first. + * Normally "lzma2" is the last filter in the chain. + * + * If one wishes to avoid spaces, for example, to avoid shell quoting, + * it is possible to use two dashes "--" instead of spaces to separate + * the filters. + * + * For xz command line compatibility, each filter may be prefixed with + * two dashes "--" and the colon ":" separating the filter name from + * the options may be replaced with an equals sign "=". + * + * By default, only filters that can be used in the .xz format are accepted. + * To allow all filters (LZMA1) use the flag LZMA_STR_ALL_FILTERS. + * + * By default, very basic validation is done for the filter chain as a whole, + * for example, that LZMA2 is only used as the last filter in the chain. + * The validation isn't perfect though and it's possible that this function + * succeeds but using the filter chain for encoding or decoding will still + * result in LZMA_OPTIONS_ERROR. To disable this validation, use the flag + * LZMA_STR_NO_VALIDATION. + * + * The available filter names and their options are available via + * lzma_str_list_filters(). See the xz man page for the description + * of filter names and options. + * + * For command line applications, below is an example how an error message + * can be displayed. Note the use of an empty string for the field width. + * If "^" was used there it would create an off-by-one error except at + * the very beginning of the line. + * + * \code{.c} + * const char *str = ...; // From user + * lzma_filter filters[LZMA_FILTERS_MAX + 1]; + * int pos; + * const char *msg = lzma_str_to_filters(str, &pos, filters, 0, NULL); + * if (msg != NULL) { + * printf("%s: Error in XZ compression options:\n", argv[0]); + * printf("%s: %s\n", argv[0], str); + * printf("%s: %*s^\n", argv[0], errpos, ""); + * printf("%s: %s\n", argv[0], msg); + * } + * \endcode + * + * \param str User-supplied string describing a preset or + * a filter chain. If a default value is needed and + * you don't know what would be good, use "6" since + * that is the default preset in xz too. + * \param[out] error_pos If this isn't NULL, this value will be set on + * both success and on all errors. This tells the + * location of the error in the string. This is + * an int to make it straightforward to use this + * as printf() field width. The value is guaranteed + * to be in the range [0, INT_MAX] even if strlen(str) + * somehow was greater than INT_MAX. + * \param[out] filters An array of lzma_filter structures. There must + * be LZMA_FILTERS_MAX + 1 (that is, five) elements + * in the array. The old contents are ignored so it + * doesn't need to be initialized. This array is + * modified only if this function returns NULL. + * Once the allocated filter options are no longer + * needed, lzma_filters_free() can be used to free the + * options (it doesn't free the filters array itself). + * \param flags Bitwise-or of zero or more of the flags + * LZMA_STR_ALL_FILTERS and LZMA_STR_NO_VALIDATION. + * \param allocator lzma_allocator for custom allocator functions. + * Set to NULL to use malloc() and free(). + * + * \return On success, NULL is returned. On error, a statically-allocated + * error message is returned which together with the error_pos + * should give some idea what is wrong. + */ +extern LZMA_API(const char *) lzma_str_to_filters( + const char *str, int *error_pos, lzma_filter *filters, + uint32_t flags, const lzma_allocator *allocator) + lzma_nothrow lzma_attr_warn_unused_result; + + +/** + * \brief Convert a filter chain to a string + * + * Use cases: + * + * - Verbose output showing the full encoder options to the user + * (use LZMA_STR_ENCODER in flags) + * + * - Showing the filters and options that are required to decode a file + * (use LZMA_STR_DECODER in flags) + * + * - Showing the filter names without any options in informational messages + * where the technical details aren't important (no flags). In this case + * the .options in the filters array are ignored and may be NULL even if + * a filter has a mandatory options structure. + * + * Note that even if the filter chain was specified using a preset, + * the resulting filter chain isn't reversed to a preset. So if you + * specify "6" to lzma_str_to_filters() then lzma_str_from_filters() + * will produce a string containing "lzma2". + * + * \param[out] str On success *str will be set to point to an + * allocated string describing the given filter + * chain. Old value is ignored. On error *str is + * always set to NULL. + * \param filters Array of filters terminated with + * .id == LZMA_VLI_UNKNOWN. + * \param flags Bitwise-or of zero or more of the flags + * LZMA_STR_ENCODER, LZMA_STR_DECODER, + * LZMA_STR_GETOPT_LONG, and LZMA_STR_NO_SPACES. + * \param allocator lzma_allocator for custom allocator functions. + * Set to NULL to use malloc() and free(). + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_OPTIONS_ERROR: Empty filter chain + * (filters[0].id == LZMA_VLI_UNKNOWN) or the filter chain + * includes a Filter ID that is not supported by this function. + * - LZMA_MEM_ERROR + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_str_from_filters( + char **str, const lzma_filter *filters, uint32_t flags, + const lzma_allocator *allocator) + lzma_nothrow lzma_attr_warn_unused_result; + + +/** + * \brief List available filters and/or their options (for help message) + * + * If a filter_id is given then only one line is created which contains the + * filter name. If LZMA_STR_ENCODER or LZMA_STR_DECODER is used then the + * options read by the encoder or decoder are printed on the same line. + * + * If filter_id is LZMA_VLI_UNKNOWN then all supported .xz-compatible filters + * are listed: + * + * - If neither LZMA_STR_ENCODER nor LZMA_STR_DECODER is used then + * the supported filter names are listed on a single line separated + * by spaces. + * + * - If LZMA_STR_ENCODER or LZMA_STR_DECODER is used then filters and + * the supported options are listed one filter per line. There won't + * be a newline after the last filter. + * + * - If LZMA_STR_ALL_FILTERS is used then the list will include also + * those filters that cannot be used in the .xz format (LZMA1). + * + * \param str On success *str will be set to point to an + * allocated string listing the filters and options. + * Old value is ignored. On error *str is always set + * to NULL. + * \param filter_id Filter ID or LZMA_VLI_UNKNOWN. + * \param flags Bitwise-or of zero or more of the flags + * LZMA_STR_ALL_FILTERS, LZMA_STR_ENCODER, + * LZMA_STR_DECODER, and LZMA_STR_GETOPT_LONG. + * \param allocator lzma_allocator for custom allocator functions. + * Set to NULL to use malloc() and free(). + * + * \return Possible lzma_ret values: + * - LZMA_OK + * - LZMA_OPTIONS_ERROR: Unsupported filter_id or flags + * - LZMA_MEM_ERROR + * - LZMA_PROG_ERROR + */ +extern LZMA_API(lzma_ret) lzma_str_list_filters( + char **str, lzma_vli filter_id, uint32_t flags, + const lzma_allocator *allocator) + lzma_nothrow lzma_attr_warn_unused_result; |