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+/**
+ * \file lzma/lzma.h
+ * \brief LZMA filter
+ *
+ * \author Copyright (C) 1999-2006 Igor Pavlov
+ * \author Copyright (C) 2007 Lasse Collin
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ */
+
+#ifndef LZMA_H_INTERNAL
+# error Never include this file directly. Use <lzma.h> instead.
+#endif
+
+
+/**
+ * \brief Filter ID
+ *
+ * Filter ID of the LZMA filter. This is used as lzma_options_filter.id.
+ */
+#define LZMA_FILTER_LZMA LZMA_VLI_C(0x40)
+
+
+/**
+ * \brief LZMA compression modes
+ *
+ * Currently there are only two modes. Earlier LZMA SDKs had also third
+ * mode between fast and best.
+ */
+typedef enum {
+ LZMA_MODE_INVALID = -1,
+ /**<
+ * \brief Invalid mode
+ *
+ * Used as array terminator in lzma_available_modes.
+ */
+
+
+ LZMA_MODE_FAST = 0,
+ /**<
+ * \brief Fast compression
+ *
+ * Fast mode is usually at its best when combined with
+ * a hash chain match finder.
+ */
+
+ LZMA_MODE_BEST = 2
+ /**<
+ * \brief Best compression ratio
+ *
+ * This is usually notably slower than fast mode. Use this
+ * together with binary tree match finders to expose the
+ * full potential of the LZMA encoder.
+ */
+} lzma_mode;
+
+
+/**
+ * \brief Match finders
+ *
+ * Match finder has major effect on both speed and compression ratio.
+ * Usually hash chains are faster than binary trees.
+ */
+typedef enum {
+ LZMA_MF_INVALID = -1,
+ /**<
+ * \brief Invalid match finder ID
+ *
+ * Used as array terminator in lzma_available_match_finders.
+ */
+
+ LZMA_MF_HC3 = 0x03,
+ /**<
+ * \brief Hash Chain with 3 bytes hashing
+ *
+ * \todo Memory requirements
+ *
+ * \note It's possible that this match finder gets
+ * removed in future. The definition will stay
+ * in this header, but liblzma may return
+ * LZMA_HEADER_ERROR if it is specified (just
+ * like it would if the match finder had been
+ * disabled at compile time).
+ */
+
+ LZMA_MF_HC4 = 0x04,
+ /**<
+ * \brief Hash Chain with 4 bytes hashing
+ *
+ * Memory requirements: 7.5 * dictionary_size + 4 MiB
+ *
+ * \note It's possible that this match finder gets
+ * removed in future. The definition will stay
+ * in this header, but liblzma may return
+ * LZMA_HEADER_ERROR if it is specified (just
+ * like it would if the match finder had been
+ * disabled at compile time).
+ */
+
+ LZMA_MF_BT2 = 0x12,
+ /**<
+ * \brief Binary Tree with 2 bytes hashing
+ *
+ * Memory requirements: 9.5 * dictionary_size + 4 MiB
+ */
+
+ LZMA_MF_BT3 = 0x13,
+ /**<
+ * \brief Binary Tree with 3 bytes hashing
+ *
+ * Memory requirements: 11.5 * dictionary_size + 4 MiB
+ */
+
+ LZMA_MF_BT4 = 0x14
+ /**<
+ * \brief Binary Tree with 4 bytes hashing
+ *
+ * Memory requirements: 11.5 * dictionary_size + 4 MiB
+ */
+} lzma_match_finder;
+
+
+/**
+ * \brief Options specific to the LZMA method handler
+ */
+typedef struct {
+ /**********************************
+ * LZMA encoding/decoding options *
+ **********************************/
+
+ /* These options are required in encoder and also with raw decoding. */
+
+ /**
+ * \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 compression ratio usually is.
+ *
+ * Raw decoding: Too big dictionary does no other harm than
+ * wasting memory. This value is ignored by lzma_raw_decode_buffer(),
+ * because it uses the target buffer as the dictionary.
+ */
+ uint32_t dictionary_size;
+# define LZMA_DICTIONARY_SIZE_MIN 1
+# define LZMA_DICTIONARY_SIZE_MAX (UINT32_C(1) << 30)
+# define LZMA_DICTIONARY_SIZE_DEFAULT (UINT32_C(1) << 23)
+
+ /**
+ * \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.
+ *
+ * \todo Example
+ */
+ uint32_t literal_context_bits;
+# define LZMA_LITERAL_CONTEXT_BITS_MIN 0
+# define LZMA_LITERAL_CONTEXT_BITS_MAX 8
+# define LZMA_LITERAL_CONTEXT_BITS_DEFAULT 3
+
+ /**
+ * \brief Number of literal position bits
+ *
+ * How many of the lowest bits of the current position (number
+ * of bytes from the beginning of the uncompressed data) in the
+ * uncompressed data is taken into account when predicting the
+ * bits of the next literal (a single eight-bit byte).
+ *
+ * \todo Example
+ */
+ uint32_t literal_pos_bits;
+# define LZMA_LITERAL_POS_BITS_MIN 0
+# define LZMA_LITERAL_POS_BITS_MAX 4
+# define LZMA_LITERAL_POS_BITS_DEFAULT 0
+
+ /**
+ * \brief Number of position bits
+ *
+ * How many of the lowest bits of the current position in the
+ * uncompressed data is taken into account when estimating
+ * probabilities of matches. A match is a sequence of bytes for
+ * which a matching sequence is found from the dictionary and
+ * thus can be stored as distance-length pair.
+ *
+ * Example: If most of the matches occur at byte positions
+ * of 8 * n + 3, that is, 3, 11, 19, ... set pos_bits to 3,
+ * because 2**3 == 8.
+ */
+ uint32_t pos_bits;
+# define LZMA_POS_BITS_MIN 0
+# define LZMA_POS_BITS_MAX 4
+# define LZMA_POS_BITS_DEFAULT 2
+
+ /**
+ * \brief Pointer to an initial dictionary
+ *
+ * It is possible to initialize the LZ77 history window using
+ * a preset dictionary. Here is a good quote from zlib's
+ * documentation; this applies to LZMA as is:
+ *
+ * "The dictionary should consist of strings (byte sequences) that
+ * are likely to be encountered later in the data to be compressed,
+ * with the most commonly used strings preferably put towards the
+ * end of the dictionary. Using a dictionary is most useful when
+ * the data to be compressed is short and can be predicted with
+ * good accuracy; the data can then be compressed better than
+ * with the default empty dictionary."
+ * (From deflateSetDictionary() in zlib.h of zlib version 1.2.3)
+ *
+ * This feature should be used only in special situations.
+ * 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 .lzma file with preset dictionary, it cannot
+ * be decoded with the regular .lzma decoder functions.
+ *
+ * \todo This feature is not implemented yet.
+ */
+ const uint8_t *preset_dictionary;
+
+ /**
+ * \brief Size of the preset dictionary
+ *
+ * Specifies the size of the preset dictionary. If the size is
+ * bigger than dictionary_size, only the last dictionary_size
+ * bytes are processed.
+ *
+ * This variable is read only when preset_dictionary is not NULL.
+ */
+ uint32_t preset_dictionary_size;
+
+ /******************************************
+ * LZMA options needed only when encoding *
+ ******************************************/
+
+ /** LZMA compression mode */
+ lzma_mode mode;
+
+ /**
+ * \brief Number of fast bytes
+ *
+ * Number of fast bytes determines how many bytes the encoder
+ * compares from the match candidates when looking for the best
+ * match. Bigger fast bytes value usually increase both compression
+ * ratio and time.
+ */
+ uint32_t fast_bytes;
+# define LZMA_FAST_BYTES_MIN 5
+# define LZMA_FAST_BYTES_MAX 273
+# define LZMA_FAST_BYTES_DEFAULT 128
+
+ /** Match finder ID */
+ lzma_match_finder match_finder;
+
+ /**
+ * \brief Match finder cycles
+ *
+ * Higher values give slightly better compression ratio but
+ * decrease speed. Use special value 0 to let liblzma use
+ * match-finder-dependent default value.
+ *
+ * \todo Write much better description.
+ */
+ uint32_t match_finder_cycles;
+
+} lzma_options_lzma;
+
+
+/**
+ * \brief Available LZMA encoding modes
+ *
+ * Pointer to an array containing the list of available encoding modes.
+ *
+ * This variable is available only if LZMA encoder has been enabled.
+ */
+extern const lzma_mode *const lzma_available_modes;
+
+
+/**
+ * \brief Available match finders
+ *
+ * Pointer to an array containing the list of available match finders.
+ * The last element is LZMA_MF_INVALID.
+ *
+ * This variable is available only if LZMA encoder has been enabled.
+ */
+extern const lzma_match_finder *const lzma_available_match_finders;
+
+
+/**
+ * \brief Table of presets for the LZMA filter
+ *
+ * lzma_presets[0] is the fastest and lzma_preset_lzma[8] is the slowest.
+ * These presets match the switches -1 .. -9 of the lzma command line tool
+ *
+ * The preset values are subject to changes between liblzma versions.
+ *
+ * This variable is available only if LZMA encoder has been enabled.
+ */
+extern const lzma_options_lzma lzma_preset_lzma[9];