diff options
author | Lasse Collin <lasse.collin@tukaani.org> | 2014-05-04 11:07:17 +0300 |
---|---|---|
committer | Lasse Collin <lasse.collin@tukaani.org> | 2014-05-04 11:07:17 +0300 |
commit | 4d5b7b3fda31241ca86ed35e08e73f776ee916e0 (patch) | |
tree | 74399fadc97b8a7c2627e99ab1de3b66477e57eb /src/liblzma/api/lzma/lzma.h | |
parent | Build: Fix the combination of --disable-xzdec --enable-lzmadec. (diff) | |
download | xz-4d5b7b3fda31241ca86ed35e08e73f776ee916e0.tar.xz |
liblzma: Rename the private API header lzma/lzma.h to lzma/lzma12.h.
It can be confusing that two header files have the same name.
The public API file is still lzma.h.
Diffstat (limited to 'src/liblzma/api/lzma/lzma.h')
-rw-r--r-- | src/liblzma/api/lzma/lzma.h | 420 |
1 files changed, 0 insertions, 420 deletions
diff --git a/src/liblzma/api/lzma/lzma.h b/src/liblzma/api/lzma/lzma.h deleted file mode 100644 index 3f8e095f..00000000 --- a/src/liblzma/api/lzma/lzma.h +++ /dev/null @@ -1,420 +0,0 @@ -/** - * \file lzma/lzma.h - * \brief LZMA1 and LZMA2 filters - */ - -/* - * 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 LZMA1 Filter ID - * - * LZMA1 is the very same thing as what was called just LZMA in LZMA Utils, - * 7-Zip, and LZMA SDK. It's called LZMA1 here to prevent developers from - * accidentally using LZMA when they actually want LZMA2. - * - * LZMA1 shouldn't be used for new applications unless you _really_ know - * what you are doing. LZMA2 is almost always a better choice. - */ -#define LZMA_FILTER_LZMA1 LZMA_VLI_C(0x4000000000000001) - -/** - * \brief LZMA2 Filter ID - * - * Usually you want this instead of LZMA1. Compared to LZMA1, LZMA2 adds - * support for LZMA_SYNC_FLUSH, uncompressed chunks (smaller expansion - * when trying to compress uncompressible data), possibility to change - * lc/lp/pb in the middle of encoding, and some other internal improvements. - */ -#define LZMA_FILTER_LZMA2 LZMA_VLI_C(0x21) - - -/** - * \brief Match finders - * - * Match finder has major effect on both speed and compression ratio. - * Usually hash chains are faster than binary trees. - * - * If you will use LZMA_SYNC_FLUSH often, the hash chains may be a better - * choice, because binary trees get much higher compression ratio penalty - * with LZMA_SYNC_FLUSH. - * - * The memory usage formulas are only rough estimates, which are closest to - * reality when dict_size is a power of two. The formulas are more complex - * in reality, and can also change a little between liblzma versions. Use - * lzma_raw_encoder_memusage() to get more accurate estimate of memory usage. - */ -typedef enum { - LZMA_MF_HC3 = 0x03, - /**< - * \brief Hash Chain with 2- and 3-byte hashing - * - * Minimum nice_len: 3 - * - * Memory usage: - * - dict_size <= 16 MiB: dict_size * 7.5 - * - dict_size > 16 MiB: dict_size * 5.5 + 64 MiB - */ - - LZMA_MF_HC4 = 0x04, - /**< - * \brief Hash Chain with 2-, 3-, and 4-byte hashing - * - * Minimum nice_len: 4 - * - * Memory usage: - * - dict_size <= 32 MiB: dict_size * 7.5 - * - dict_size > 32 MiB: dict_size * 6.5 - */ - - LZMA_MF_BT2 = 0x12, - /**< - * \brief Binary Tree with 2-byte hashing - * - * Minimum nice_len: 2 - * - * Memory usage: dict_size * 9.5 - */ - - LZMA_MF_BT3 = 0x13, - /**< - * \brief Binary Tree with 2- and 3-byte hashing - * - * Minimum nice_len: 3 - * - * Memory usage: - * - dict_size <= 16 MiB: dict_size * 11.5 - * - dict_size > 16 MiB: dict_size * 9.5 + 64 MiB - */ - - LZMA_MF_BT4 = 0x14 - /**< - * \brief Binary Tree with 2-, 3-, and 4-byte hashing - * - * Minimum nice_len: 4 - * - * Memory usage: - * - dict_size <= 32 MiB: dict_size * 11.5 - * - dict_size > 32 MiB: dict_size * 10.5 - */ -} lzma_match_finder; - - -/** - * \brief Test if given match finder is supported - * - * Return true if the given match finder is supported by this liblzma build. - * Otherwise false is returned. It is safe to call this with a value that - * isn't listed in lzma_match_finder enumeration; the return value will be - * false. - * - * There is no way to list which match finders are available in this - * particular liblzma version and build. It would be useless, because - * a new match finder, which the application developer wasn't aware, - * could require giving additional options to the encoder that the older - * match finders don't need. - */ -extern LZMA_API(lzma_bool) lzma_mf_is_supported(lzma_match_finder match_finder) - lzma_nothrow lzma_attr_const; - - -/** - * \brief Compression modes - * - * This selects the function used to analyze the data produced by the match - * finder. - */ -typedef enum { - LZMA_MODE_FAST = 1, - /**< - * \brief Fast compression - * - * Fast mode is usually at its best when combined with - * a hash chain match finder. - */ - - LZMA_MODE_NORMAL = 2 - /**< - * \brief Normal compression - * - * This is usually notably slower than fast mode. Use this - * together with binary tree match finders to expose the - * full potential of the LZMA1 or LZMA2 encoder. - */ -} lzma_mode; - - -/** - * \brief Test if given compression mode is supported - * - * Return true if the given compression mode is supported by this liblzma - * build. Otherwise false is returned. It is safe to call this with a value - * that isn't listed in lzma_mode enumeration; the return value will be false. - * - * There is no way to list which modes are available in this particular - * liblzma version and build. It would be useless, because a new compression - * mode, which the application developer wasn't aware, could require giving - * additional options to the encoder that the older modes don't need. - */ -extern LZMA_API(lzma_bool) lzma_mode_is_supported(lzma_mode mode) - lzma_nothrow lzma_attr_const; - - -/** - * \brief Options specific to the LZMA1 and LZMA2 filters - * - * Since LZMA1 and LZMA2 share most of the code, it's simplest to share - * the options structure too. For encoding, all but the reserved variables - * need to be initialized unless specifically mentioned otherwise. - * lzma_lzma_preset() can be used to get a good starting point. - * - * For raw decoding, both LZMA1 and LZMA2 need dict_size, preset_dict, and - * preset_dict_size (if preset_dict != NULL). LZMA1 needs also lc, lp, and pb. - */ -typedef struct { - /** - * \brief Dictionary size in bytes - * - * Dictionary size indicates how many bytes of the recently processed - * uncompressed data is kept in memory. One method to reduce size of - * the uncompressed data is to store distance-length pairs, which - * indicate what data to repeat from the dictionary buffer. Thus, - * the bigger the dictionary, the better the compression ratio - * usually is. - * - * Maximum size of the dictionary depends on multiple things: - * - Memory usage limit - * - Available address space (not a problem on 64-bit systems) - * - Selected match finder (encoder only) - * - * Currently the maximum dictionary size for encoding is 1.5 GiB - * (i.e. (UINT32_C(1) << 30) + (UINT32_C(1) << 29)) even on 64-bit - * systems for certain match finder implementation reasons. In the - * future, there may be match finders that support bigger - * dictionaries. - * - * Decoder already supports dictionaries up to 4 GiB - 1 B (i.e. - * UINT32_MAX), so increasing the maximum dictionary size of the - * encoder won't cause problems for old decoders. - * - * Because extremely small dictionaries sizes would have unneeded - * overhead in the decoder, the minimum dictionary size is 4096 bytes. - * - * \note When decoding, too big dictionary does no other harm - * than wasting memory. - */ - uint32_t dict_size; -# define LZMA_DICT_SIZE_MIN UINT32_C(4096) -# define LZMA_DICT_SIZE_DEFAULT (UINT32_C(1) << 23) - - /** - * \brief Pointer to an initial dictionary - * - * It is possible to initialize the LZ77 history window using - * a preset dictionary. It is useful when compressing many - * similar, relatively small chunks of data independently from - * each other. The preset dictionary should contain typical - * strings that occur in the files being compressed. The most - * probable strings should be near the end of the preset dictionary. - * - * This feature should be used only in special situations. For - * now, it works correctly only with raw encoding and decoding. - * Currently none of the container formats supported by - * liblzma allow preset dictionary when decoding, thus if - * you create a .xz or .lzma file with preset dictionary, it - * cannot be decoded with the regular decoder functions. In the - * future, the .xz format will likely get support for preset - * dictionary though. - */ - const uint8_t *preset_dict; - - /** - * \brief Size of the preset dictionary - * - * Specifies the size of the preset dictionary. If the size is - * bigger than dict_size, only the last dict_size bytes are - * processed. - * - * This variable is read only when preset_dict is not NULL. - * If preset_dict is not NULL but preset_dict_size is zero, - * no preset dictionary is used (identical to only setting - * preset_dict to NULL). - */ - uint32_t preset_dict_size; - - /** - * \brief Number of literal context bits - * - * How many of the highest bits of the previous uncompressed - * eight-bit byte (also known as `literal') are taken into - * account when predicting the bits of the next literal. - * - * E.g. in typical English text, an upper-case letter is - * often followed by a lower-case letter, and a lower-case - * letter is usually followed by another lower-case letter. - * In the US-ASCII character set, the highest three bits are 010 - * for upper-case letters and 011 for lower-case letters. - * When lc is at least 3, the literal coding can take advantage of - * this property in the uncompressed data. - * - * There is a limit that applies to literal context bits and literal - * position bits together: lc + lp <= 4. Without this limit the - * decoding could become very slow, which could have security related - * results in some cases like email servers doing virus scanning. - * This limit also simplifies the internal implementation in liblzma. - * - * There may be LZMA1 streams that have lc + lp > 4 (maximum possible - * lc would be 8). It is not possible to decode such streams with - * liblzma. - */ - uint32_t lc; -# define LZMA_LCLP_MIN 0 -# define LZMA_LCLP_MAX 4 -# define LZMA_LC_DEFAULT 3 - - /** - * \brief Number of literal position bits - * - * lp affects what kind of alignment in the uncompressed data is - * assumed when encoding literals. A literal is a single 8-bit byte. - * See pb below for more information about alignment. - */ - uint32_t lp; -# define LZMA_LP_DEFAULT 0 - - /** - * \brief Number of position bits - * - * pb affects what kind of alignment in the uncompressed data is - * assumed in general. The default means four-byte alignment - * (2^ pb =2^2=4), which is often a good choice when there's - * no better guess. - * - * When the aligment is known, setting pb accordingly may reduce - * the file size a little. E.g. with text files having one-byte - * alignment (US-ASCII, ISO-8859-*, UTF-8), setting pb=0 can - * improve compression slightly. For UTF-16 text, pb=1 is a good - * choice. If the alignment is an odd number like 3 bytes, pb=0 - * might be the best choice. - * - * Even though the assumed alignment can be adjusted with pb and - * lp, LZMA1 and LZMA2 still slightly favor 16-byte alignment. - * It might be worth taking into account when designing file formats - * that are likely to be often compressed with LZMA1 or LZMA2. - */ - uint32_t pb; -# define LZMA_PB_MIN 0 -# define LZMA_PB_MAX 4 -# define LZMA_PB_DEFAULT 2 - - /** Compression mode */ - lzma_mode mode; - - /** - * \brief Nice length of a match - * - * This determines how many bytes the encoder compares from the match - * candidates when looking for the best match. Once a match of at - * least nice_len bytes long is found, the encoder stops looking for - * better candidates and encodes the match. (Naturally, if the found - * match is actually longer than nice_len, the actual length is - * encoded; it's not truncated to nice_len.) - * - * Bigger values usually increase the compression ratio and - * compression time. For most files, 32 to 128 is a good value, - * which gives very good compression ratio at good speed. - * - * The exact minimum value depends on the match finder. The maximum - * is 273, which is the maximum length of a match that LZMA1 and - * LZMA2 can encode. - */ - uint32_t nice_len; - - /** Match finder ID */ - lzma_match_finder mf; - - /** - * \brief Maximum search depth in the match finder - * - * For every input byte, match finder searches through the hash chain - * or binary tree in a loop, each iteration going one step deeper in - * the chain or tree. The searching stops if - * - a match of at least nice_len bytes long is found; - * - all match candidates from the hash chain or binary tree have - * been checked; or - * - maximum search depth is reached. - * - * Maximum search depth is needed to prevent the match finder from - * wasting too much time in case there are lots of short match - * candidates. On the other hand, stopping the search before all - * candidates have been checked can reduce compression ratio. - * - * Setting depth to zero tells liblzma to use an automatic default - * value, that depends on the selected match finder and nice_len. - * The default is in the range [4, 200] or so (it may vary between - * liblzma versions). - * - * Using a bigger depth value than the default can increase - * compression ratio in some cases. There is no strict maximum value, - * but high values (thousands or millions) should be used with care: - * the encoder could remain fast enough with typical input, but - * malicious input could cause the match finder to slow down - * dramatically, possibly creating a denial of service attack. - */ - uint32_t depth; - - /* - * Reserved space to allow possible future extensions without - * breaking the ABI. You should not touch these, because the names - * of these variables may change. These are and will never be used - * with the currently supported options, so it is safe to leave these - * uninitialized. - */ - uint32_t reserved_int1; - uint32_t reserved_int2; - uint32_t reserved_int3; - uint32_t reserved_int4; - uint32_t reserved_int5; - uint32_t reserved_int6; - uint32_t reserved_int7; - uint32_t reserved_int8; - lzma_reserved_enum reserved_enum1; - lzma_reserved_enum reserved_enum2; - lzma_reserved_enum reserved_enum3; - lzma_reserved_enum reserved_enum4; - void *reserved_ptr1; - void *reserved_ptr2; - -} lzma_options_lzma; - - -/** - * \brief Set a compression preset to lzma_options_lzma structure - * - * 0 is the fastest and 9 is the slowest. These match the switches -0 .. -9 - * of the xz command line tool. In addition, it is possible to bitwise-or - * flags to the preset. Currently only LZMA_PRESET_EXTREME is supported. - * The flags are defined in container.h, because the flags are used also - * with lzma_easy_encoder(). - * - * The preset values are subject to changes between liblzma versions. - * - * This function is available only if LZMA1 or LZMA2 encoder has been enabled - * when building liblzma. - * - * \return On success, false is returned. If the preset is not - * supported, true is returned. - */ -extern LZMA_API(lzma_bool) lzma_lzma_preset( - lzma_options_lzma *options, uint32_t preset) lzma_nothrow; |