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author | mm <mm@FreeBSD.org> | 2010-05-10 06:59:50 +0000 |
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committer | mm <mm@FreeBSD.org> | 2010-05-10 06:59:50 +0000 |
commit | 5c358d45429b654efa9c8177ecd370a7965ec1a7 (patch) | |
tree | d2d916954c6a66a3168ee356b5f24da01c2017d6 /contrib/xz/src/liblzma/lz/lz_encoder.h | |
parent | 3e09decd1986826f54af1a47be97bb87c1220783 (diff) | |
parent | 1008b7c6744a190c5b15aaf8cab1054671e4c7c3 (diff) | |
download | FreeBSD-src-5c358d45429b654efa9c8177ecd370a7965ec1a7.zip FreeBSD-src-5c358d45429b654efa9c8177ecd370a7965ec1a7.tar.gz |
Import of liblzma, xz, xzdec, lzmainfo from vendor branch
Add support for xz and lzma to lesspipe.sh (xzless, lzless)
Bump __FreeBSD_version
Approved by: delphij (mentor)
MFC after: 2 weeks
Diffstat (limited to 'contrib/xz/src/liblzma/lz/lz_encoder.h')
-rw-r--r-- | contrib/xz/src/liblzma/lz/lz_encoder.h | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/contrib/xz/src/liblzma/lz/lz_encoder.h b/contrib/xz/src/liblzma/lz/lz_encoder.h new file mode 100644 index 0000000..f6352a4 --- /dev/null +++ b/contrib/xz/src/liblzma/lz/lz_encoder.h @@ -0,0 +1,328 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lz_encoder.h +/// \brief LZ in window and match finder API +/// +// Authors: Igor Pavlov +// Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#ifndef LZMA_LZ_ENCODER_H +#define LZMA_LZ_ENCODER_H + +#include "common.h" + + +/// A table of these is used by the LZ-based encoder to hold +/// the length-distance pairs found by the match finder. +typedef struct { + uint32_t len; + uint32_t dist; +} lzma_match; + + +typedef struct lzma_mf_s lzma_mf; +struct lzma_mf_s { + /////////////// + // In Window // + /////////////// + + /// Pointer to buffer with data to be compressed + uint8_t *buffer; + + /// Total size of the allocated buffer (that is, including all + /// the extra space) + uint32_t size; + + /// Number of bytes that must be kept available in our input history. + /// That is, once keep_size_before bytes have been processed, + /// buffer[read_pos - keep_size_before] is the oldest byte that + /// must be available for reading. + uint32_t keep_size_before; + + /// Number of bytes that must be kept in buffer after read_pos. + /// That is, read_pos <= write_pos - keep_size_after as long as + /// action is LZMA_RUN; when action != LZMA_RUN, read_pos is allowed + /// to reach write_pos so that the last bytes get encoded too. + uint32_t keep_size_after; + + /// Match finders store locations of matches using 32-bit integers. + /// To avoid adjusting several megabytes of integers every time the + /// input window is moved with move_window, we only adjust the + /// offset of the buffer. Thus, buffer[value_in_hash_table - offset] + /// is the byte pointed by value_in_hash_table. + uint32_t offset; + + /// buffer[read_pos] is the next byte to run through the match + /// finder. This is incremented in the match finder once the byte + /// has been processed. + uint32_t read_pos; + + /// Number of bytes that have been ran through the match finder, but + /// which haven't been encoded by the LZ-based encoder yet. + uint32_t read_ahead; + + /// As long as read_pos is less than read_limit, there is enough + /// input available in buffer for at least one encoding loop. + /// + /// Because of the stateful API, read_limit may and will get greater + /// than read_pos quite often. This is taken into account when + /// calculating the value for keep_size_after. + uint32_t read_limit; + + /// buffer[write_pos] is the first byte that doesn't contain valid + /// uncompressed data; that is, the next input byte will be copied + /// to buffer[write_pos]. + uint32_t write_pos; + + /// Number of bytes not hashed before read_pos. This is needed to + /// restart the match finder after LZMA_SYNC_FLUSH. + uint32_t pending; + + ////////////////// + // Match Finder // + ////////////////// + + /// Find matches. Returns the number of distance-length pairs written + /// to the matches array. This is called only via lzma_mf_find(). + uint32_t (*find)(lzma_mf *mf, lzma_match *matches); + + /// Skips num bytes. This is like find() but doesn't make the + /// distance-length pairs available, thus being a little faster. + /// This is called only via mf_skip(). + void (*skip)(lzma_mf *mf, uint32_t num); + + uint32_t *hash; + uint32_t *son; + uint32_t cyclic_pos; + uint32_t cyclic_size; // Must be dictionary size + 1. + uint32_t hash_mask; + + /// Maximum number of loops in the match finder + uint32_t depth; + + /// Maximum length of a match that the match finder will try to find. + uint32_t nice_len; + + /// Maximum length of a match supported by the LZ-based encoder. + /// If the longest match found by the match finder is nice_len, + /// mf_find() tries to expand it up to match_len_max bytes. + uint32_t match_len_max; + + /// When running out of input, binary tree match finders need to know + /// if it is due to flushing or finishing. The action is used also + /// by the LZ-based encoders themselves. + lzma_action action; + + /// Number of elements in hash[] + uint32_t hash_size_sum; + + /// Number of elements in son[] + uint32_t sons_count; +}; + + +typedef struct { + /// Extra amount of data to keep available before the "actual" + /// dictionary. + size_t before_size; + + /// Size of the history buffer + size_t dict_size; + + /// Extra amount of data to keep available after the "actual" + /// dictionary. + size_t after_size; + + /// Maximum length of a match that the LZ-based encoder can accept. + /// This is used to extend matches of length nice_len to the + /// maximum possible length. + size_t match_len_max; + + /// Match finder will search matches up to this length. + /// This must be less than or equal to match_len_max. + size_t nice_len; + + /// Type of the match finder to use + lzma_match_finder match_finder; + + /// Maximum search depth + uint32_t depth; + + /// TODO: Comment + const uint8_t *preset_dict; + + uint32_t preset_dict_size; + +} lzma_lz_options; + + +// The total usable buffer space at any moment outside the match finder: +// before_size + dict_size + after_size + match_len_max +// +// In reality, there's some extra space allocated to prevent the number of +// memmove() calls reasonable. The bigger the dict_size is, the bigger +// this extra buffer will be since with bigger dictionaries memmove() would +// also take longer. +// +// A single encoder loop in the LZ-based encoder may call the match finder +// (mf_find() or mf_skip()) at most after_size times. In other words, +// a single encoder loop may increment lzma_mf.read_pos at most after_size +// times. Since matches are looked up to +// lzma_mf.buffer[lzma_mf.read_pos + match_len_max - 1], the total +// amount of extra buffer needed after dict_size becomes +// after_size + match_len_max. +// +// before_size has two uses. The first one is to keep literals available +// in cases when the LZ-based encoder has made some read ahead. +// TODO: Maybe this could be changed by making the LZ-based encoders to +// store the actual literals as they do with length-distance pairs. +// +// Algorithms such as LZMA2 first try to compress a chunk, and then check +// if the encoded result is smaller than the uncompressed one. If the chunk +// was uncompressible, it is better to store it in uncompressed form in +// the output stream. To do this, the whole uncompressed chunk has to be +// still available in the history buffer. before_size achieves that. + + +typedef struct { + /// Data specific to the LZ-based encoder + lzma_coder *coder; + + /// Function to encode from *dict to out[] + lzma_ret (*code)(lzma_coder *restrict coder, + lzma_mf *restrict mf, uint8_t *restrict out, + size_t *restrict out_pos, size_t out_size); + + /// Free allocated resources + void (*end)(lzma_coder *coder, lzma_allocator *allocator); + + /// Update the options in the middle of the encoding. + lzma_ret (*options_update)(lzma_coder *coder, + const lzma_filter *filter); + +} lzma_lz_encoder; + + +// Basic steps: +// 1. Input gets copied into the dictionary. +// 2. Data in dictionary gets run through the match finder byte by byte. +// 3. The literals and matches are encoded using e.g. LZMA. +// +// The bytes that have been ran through the match finder, but not encoded yet, +// are called `read ahead'. + + +/// Get pointer to the first byte not ran through the match finder +static inline const uint8_t * +mf_ptr(const lzma_mf *mf) +{ + return mf->buffer + mf->read_pos; +} + + +/// Get the number of bytes that haven't been ran through the match finder yet. +static inline uint32_t +mf_avail(const lzma_mf *mf) +{ + return mf->write_pos - mf->read_pos; +} + + +/// Get the number of bytes that haven't been encoded yet (some of these +/// bytes may have been ran through the match finder though). +static inline uint32_t +mf_unencoded(const lzma_mf *mf) +{ + return mf->write_pos - mf->read_pos + mf->read_ahead; +} + + +/// Calculate the absolute offset from the beginning of the most recent +/// dictionary reset. Only the lowest four bits are important, so there's no +/// problem that we don't know the 64-bit size of the data encoded so far. +/// +/// NOTE: When moving the input window, we need to do it so that the lowest +/// bits of dict->read_pos are not modified to keep this macro working +/// as intended. +static inline uint32_t +mf_position(const lzma_mf *mf) +{ + return mf->read_pos - mf->read_ahead; +} + + +/// Since everything else begins with mf_, use it also for lzma_mf_find(). +#define mf_find lzma_mf_find + + +/// Skip the given number of bytes. This is used when a good match was found. +/// For example, if mf_find() finds a match of 200 bytes long, the first byte +/// of that match was already consumed by mf_find(), and the rest 199 bytes +/// have to be skipped with mf_skip(mf, 199). +static inline void +mf_skip(lzma_mf *mf, uint32_t amount) +{ + if (amount != 0) { + mf->skip(mf, amount); + mf->read_ahead += amount; + } +} + + +/// Copies at most *left number of bytes from the history buffer +/// to out[]. This is needed by LZMA2 to encode uncompressed chunks. +static inline void +mf_read(lzma_mf *mf, uint8_t *out, size_t *out_pos, size_t out_size, + size_t *left) +{ + const size_t out_avail = out_size - *out_pos; + const size_t copy_size = MIN(out_avail, *left); + + assert(mf->read_ahead == 0); + assert(mf->read_pos >= *left); + + memcpy(out + *out_pos, mf->buffer + mf->read_pos - *left, + copy_size); + + *out_pos += copy_size; + *left -= copy_size; + return; +} + + +extern lzma_ret lzma_lz_encoder_init( + lzma_next_coder *next, lzma_allocator *allocator, + const lzma_filter_info *filters, + lzma_ret (*lz_init)(lzma_lz_encoder *lz, + lzma_allocator *allocator, const void *options, + lzma_lz_options *lz_options)); + + +extern uint64_t lzma_lz_encoder_memusage(const lzma_lz_options *lz_options); + + +// These are only for LZ encoder's internal use. +extern uint32_t lzma_mf_find( + lzma_mf *mf, uint32_t *count, lzma_match *matches); + +extern uint32_t lzma_mf_hc3_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_hc3_skip(lzma_mf *dict, uint32_t amount); + +extern uint32_t lzma_mf_hc4_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_hc4_skip(lzma_mf *dict, uint32_t amount); + +extern uint32_t lzma_mf_bt2_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_bt2_skip(lzma_mf *dict, uint32_t amount); + +extern uint32_t lzma_mf_bt3_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_bt3_skip(lzma_mf *dict, uint32_t amount); + +extern uint32_t lzma_mf_bt4_find(lzma_mf *dict, lzma_match *matches); +extern void lzma_mf_bt4_skip(lzma_mf *dict, uint32_t amount); + +#endif |