--- /dev/null
+/**
+ * \file lzma/lzma12.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;
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