--- /dev/null
+/**
+ * \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;
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