diff options
Diffstat (limited to 'src/liblzma/api/lzma/stream.h')
| -rw-r--r-- | src/liblzma/api/lzma/stream.h | 157 |
1 files changed, 16 insertions, 141 deletions
diff --git a/src/liblzma/api/lzma/stream.h b/src/liblzma/api/lzma/stream.h index 346bdd17..4bb17e7d 100644 --- a/src/liblzma/api/lzma/stream.h +++ b/src/liblzma/api/lzma/stream.h @@ -22,157 +22,32 @@ /** - * \brief Options for .lzma Stream encoder - */ -typedef struct { - /** - * \brief Type of integrity Check - * - * The type of the integrity Check is stored into Stream Header - * and Stream Footer. The same Check is used for all Blocks in - * the Stream. - */ - lzma_check_type check; - - /** - * \brief Precense of CRC32 of the Block Header - * - * Set this to true if CRC32 of every Block Header should be - * calculated and stored in the Block Header. This is recommended. - * - * This setting is stored into Stream Header and Stream Footer. - */ - lzma_bool has_crc32; - - /** - * \brief Uncompressed Size in bytes - * - * This is somewhat advanced feature. Most users want to set this to - * LZMA_VLI_VALUE_UNKNOWN to indicate unknown Uncompressed Size. - * - * If the Uncompressed Size of the Stream being encoded is known, - * it can be stored to the beginning of the Stream. The details - * differ for Single-Block and Multi-Block Streams: - * - With Single-Block Streams, the Uncompressed Size is stored to - * the Block Header and End of Payload Marker is omitted. - * - With Multi-Block Streams, the Uncompressed Size is stored to - * the Header Metadata Block. The Uncompressed Size of the Blocks - * will be unknown, because liblzma cannot predict how the - * application is going to split the data in Blocks. - */ - lzma_vli uncompressed_size; - - /** - * \brief Alignment of the beginning of the Stream - * - * Certain filters handle data in bigger chunks than single bytes. - * This affects two things: - * - Performance: aligned memory access is usually faster. - * - Further compression ratio in custom file formats: if you - * encode multiple Blocks with some non-compression filter - * such as LZMA_FILTER_POWERPC, it is a good idea to keep - * the inter-Block alignment correct to maximize compression - * ratio when all these Blocks are finally compressed as a - * single step. - * - * Usually the Stream is stored into its own file, thus - * the alignment is usually zero. - */ - uint32_t alignment; - - /** - * \brief Array of filters used to encode Data Blocks - * - * There can be at maximum of seven filters. The end of the array is - * marked with .id = LZMA_VLI_VALUE_UNKNOWN. (That's why the array - * has eight members.) Minimum number of filters is zero; in that - * case, an implicit Copy filter is used. - */ - lzma_options_filter filters[8]; - - /** - * \brief Array of filters used to encode Metadata Blocks - * - * This is like filters[] but for Metadata Blocks. If Metadata - * Blocks are compressed, they usually are compressed with - * settings that require only little memory to uncompress e.g. - * LZMA with 64 KiB dictionary. - * - * \todo Recommend a preset. - * - * When liblzma sees that the Metadata Block would be very small - * even in uncompressed form, it is not compressed no matter - * what filter have been set here. This is to avoid possibly - * increasing the size of the Metadata Block with bad compression, - * and to avoid useless overhead of filters in uncompression phase. - */ - lzma_options_filter metadata_filters[8]; - - /** - * \brief Extra information in the Header Metadata Block - */ - const lzma_extra *header; - - /** - * \brief Extra information in the Footer Metadata Block - * - * It is enough to set this pointer any time before calling - * lzma_code() with LZMA_FINISH as the second argument. - */ - const lzma_extra *footer; - -} lzma_options_stream; - - -/** - * \brief Initializes Single-Block .lzma Stream encoder - * - * This is the function that most developers are looking for. :-) It - * compresses using the specified options without storing any extra - * information. + * \brief Initializes .lzma Stream encoder * - * \todo Describe that is_metadata is ignored, maybe something else. - */ -extern lzma_ret lzma_stream_encoder_single( - lzma_stream *strm, const lzma_options_stream *options); - - -/** - * \brief Initializes Multi-Block .lzma Stream encoder + * \param strm Pointer to properly prepared lzma_stream + * \param filters Array of filters. This must be terminated with + * filters[n].id = LZMA_VLI_VALUE_UNKNOWN. There must + * be 1-4 filters, but there are restrictions on how + * multiple filters can be combined. FIXME Tell where + * to find more information. + * \param check Type of the integrity check to calculate from + * uncompressed data. * + * \return - LZMA_OK: Initialization was successful. + * - LZMA_MEM_ERROR + * - LZMA_HEADER_ERROR + * - LZMA_PROG_ERROR */ -extern lzma_ret lzma_stream_encoder_multi( - lzma_stream *strm, const lzma_options_stream *options); +extern lzma_ret lzma_stream_encoder(lzma_stream *strm, + const lzma_options_filter *filters, lzma_check_type check); /** * \brief Initializes decoder for .lzma Stream * * \param strm Pointer to propertily prepared lzma_stream - * \param header Pointer to hold a pointer to Extra Records read - * from the Header Metadata Block. Use NULL if - * you don't care about Extra Records. - * \param footer Same as header, but for Footer Metadata Block. * * \return - LZMA_OK: Initialization was successful. * - LZMA_MEM_ERROR: Cannot allocate memory. - * - * If header and/or footer are not NULL, *header and/or *footer will be - * initially set to NULL. - * - * The application can detect that Header Metadata Block has been completely - * parsed when the decoder procudes some output the first time. If *header - * is still NULL, there was no Extra field in the Header Metadata Block (or - * the whole Header Metadata Block wasn't present at all). - * - * The application can detect that Footer Metadata Block has been parsed - * completely when lzma_code() returns LZMA_STREAM_END. If *footer is still - * NULL, there was no Extra field in the Footer Metadata Block. - * - * \note If you use lzma_memory_limiter, the Extra Records will be - * allocated with it, and thus remain in the lzma_memory_limiter - * even after they get exported to the application via *header - * and *footer pointers. */ -extern lzma_ret lzma_stream_decoder(lzma_stream *strm, - lzma_extra **header, lzma_extra **footer); +extern lzma_ret lzma_stream_decoder(lzma_stream *strm); |