| Current File : //usr/include/lzma/filter.h |
/**
* \file lzma/filter.h
* \brief Common filter related types and functions
*/
/*
* Author: Lasse Collin
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*
* See ../lzma.h for information about liblzma as a whole.
*/
#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 Filter ID and a pointer 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 too small
* array would make liblzma write past the end of the filters 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
*
* Return true if the give Filter ID is supported for encoding by this
* liblzma build. Otherwise false is returned.
*
* There is no way to list which filters are available in this particular
* liblzma version and build. It would be useless, because the application
* couldn't know what kind of options the filter would need.
*/
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
*
* Return true if the give Filter ID is supported for decoding by this
* liblzma build. Otherwise false is returned.
*/
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.
*
* \return - 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;
/**
* \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. If an error occurs,
* for example due to unsupported filter chain,
* UINT64_MAX is returned.
*/
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. If an error occurs,
* for example due to unsupported filter chain,
* UINT64_MAX is returned.
*/
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.
*
* \param strm Pointer to properly prepared lzma_stream
* \param filters Array of lzma_filter structures. The end of the
* array must be marked with .id = LZMA_VLI_UNKNOWN.
*
* The `action' with lzma_code() can be LZMA_RUN, LZMA_SYNC_FLUSH (if the
* filter chain supports it), or LZMA_FINISH.
*
* \return - 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.
*
* \return - 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 is for advanced users only. This function has two slightly
* different purposes:
*
* - After LZMA_FULL_FLUSH when using Stream encoder: Set a new filter
* chain, which will be used starting from the next Block.
*
* - After LZMA_SYNC_FLUSH using Raw, Block, or Stream encoder: Change
* the filter-specific options in the middle of encoding. The actual
* filters in the chain (Filter IDs) cannot be changed. In the future,
* it might become possible to change the filter options without
* using LZMA_SYNC_FLUSH.
*
* While rarely useful, this function may be called also when no data has
* been compressed yet. In that case, this function will behave as if
* LZMA_FULL_FLUSH (Stream encoder) or LZMA_SYNC_FLUSH (Raw or Block
* encoder) had been used right before calling this function.
*
* \return - 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
*
* \param filters Array of lzma_filter structures. The end of the
* array must be marked 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 Beginning of the output buffer
* \param 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 - 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
*
* \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.)
*/
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 lzma_filter structures. The end of the
* array must be marked 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 Beginning of the output buffer
* \param 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].
*/
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.
*
* \param 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 - LZMA_OK
* - LZMA_OPTIONS_ERROR
* - LZMA_PROG_ERROR
*
* \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.
*/
extern LZMA_API(lzma_ret) lzma_properties_size(
uint32_t *size, const lzma_filter *filter) lzma_nothrow;
/**
* \brief Encode the Filter Properties field
*
* \param filter Filter ID and options
* \param props Buffer to hold the encoded options. The size of
* buffer must have been already determined with
* lzma_properties_size().
*
* \return - LZMA_OK
* - LZMA_OPTIONS_ERROR
* - LZMA_PROG_ERROR
*
* \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.
*/
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 to filter->options.
* filter->options is set to NULL if there are no
* properties or if an error occurs.
* \param allocator Custom memory allocator used to allocate the
* options. Set to NULL to use the default malloc(),
* 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 - 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.
*
* \param size Pointer to integer to hold the calculated size
* \param filter Filter ID and associated options whose encoded
* size is to be calculated
*
* \return - 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
*
* \note If you need to calculate size of List of Filter Flags,
* you need to loop over every lzma_filter entry.
*/
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 Beginning of the output buffer
* \param 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 - 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.
*
* \return - LZMA_OK
* - LZMA_OPTIONS_ERROR
* - LZMA_MEM_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;