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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_decoder.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_decoder.h')
-rw-r--r-- | contrib/xz/src/liblzma/lz/lz_decoder.h | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/contrib/xz/src/liblzma/lz/lz_decoder.h b/contrib/xz/src/liblzma/lz/lz_decoder.h new file mode 100644 index 0000000..bf1609d --- /dev/null +++ b/contrib/xz/src/liblzma/lz/lz_decoder.h @@ -0,0 +1,234 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file lz_decoder.h +/// \brief LZ out window +/// +// 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_DECODER_H +#define LZMA_LZ_DECODER_H + +#include "common.h" + + +typedef struct { + /// Pointer to the dictionary buffer. It can be an allocated buffer + /// internal to liblzma, or it can a be a buffer given by the + /// application when in single-call mode (not implemented yet). + uint8_t *buf; + + /// Write position in dictionary. The next byte will be written to + /// buf[pos]. + size_t pos; + + /// Indicates how full the dictionary is. This is used by + /// dict_is_distance_valid() to detect corrupt files that would + /// read beyond the beginning of the dictionary. + size_t full; + + /// Write limit + size_t limit; + + /// Size of the dictionary + size_t size; + + /// True when dictionary should be reset before decoding more data. + bool need_reset; + +} lzma_dict; + + +typedef struct { + size_t dict_size; + const uint8_t *preset_dict; + size_t preset_dict_size; +} lzma_lz_options; + + +typedef struct { + /// Data specific to the LZ-based decoder + lzma_coder *coder; + + /// Function to decode from in[] to *dict + lzma_ret (*code)(lzma_coder *restrict coder, + lzma_dict *restrict dict, const uint8_t *restrict in, + size_t *restrict in_pos, size_t in_size); + + void (*reset)(lzma_coder *coder, const void *options); + + /// Set the uncompressed size + void (*set_uncompressed)(lzma_coder *coder, + lzma_vli uncompressed_size); + + /// Free allocated resources + void (*end)(lzma_coder *coder, lzma_allocator *allocator); + +} lzma_lz_decoder; + + +#define LZMA_LZ_DECODER_INIT \ + (lzma_lz_decoder){ \ + .coder = NULL, \ + .code = NULL, \ + .reset = NULL, \ + .set_uncompressed = NULL, \ + .end = NULL, \ + } + + +extern lzma_ret lzma_lz_decoder_init(lzma_next_coder *next, + lzma_allocator *allocator, const lzma_filter_info *filters, + lzma_ret (*lz_init)(lzma_lz_decoder *lz, + lzma_allocator *allocator, const void *options, + lzma_lz_options *lz_options)); + +extern uint64_t lzma_lz_decoder_memusage(size_t dictionary_size); + +extern void lzma_lz_decoder_uncompressed( + lzma_coder *coder, lzma_vli uncompressed_size); + + +////////////////////// +// Inline functions // +////////////////////// + +/// Get a byte from the history buffer. +static inline uint8_t +dict_get(const lzma_dict *const dict, const uint32_t distance) +{ + return dict->buf[dict->pos - distance - 1 + + (distance < dict->pos ? 0 : dict->size)]; +} + + +/// Test if dictionary is empty. +static inline bool +dict_is_empty(const lzma_dict *const dict) +{ + return dict->full == 0; +} + + +/// Validate the match distance +static inline bool +dict_is_distance_valid(const lzma_dict *const dict, const size_t distance) +{ + return dict->full > distance; +} + + +/// Repeat *len bytes at distance. +static inline bool +dict_repeat(lzma_dict *dict, uint32_t distance, uint32_t *len) +{ + // Don't write past the end of the dictionary. + const size_t dict_avail = dict->limit - dict->pos; + uint32_t left = MIN(dict_avail, *len); + *len -= left; + + // Repeat a block of data from the history. Because memcpy() is faster + // than copying byte by byte in a loop, the copying process gets split + // into three cases. + if (distance < left) { + // Source and target areas overlap, thus we can't use + // memcpy() nor even memmove() safely. + do { + dict->buf[dict->pos] = dict_get(dict, distance); + ++dict->pos; + } while (--left > 0); + + } else if (distance < dict->pos) { + // The easiest and fastest case + memcpy(dict->buf + dict->pos, + dict->buf + dict->pos - distance - 1, + left); + dict->pos += left; + + } else { + // The bigger the dictionary, the more rare this + // case occurs. We need to "wrap" the dict, thus + // we might need two memcpy() to copy all the data. + assert(dict->full == dict->size); + const uint32_t copy_pos + = dict->pos - distance - 1 + dict->size; + uint32_t copy_size = dict->size - copy_pos; + + if (copy_size < left) { + memmove(dict->buf + dict->pos, dict->buf + copy_pos, + copy_size); + dict->pos += copy_size; + copy_size = left - copy_size; + memcpy(dict->buf + dict->pos, dict->buf, copy_size); + dict->pos += copy_size; + } else { + memmove(dict->buf + dict->pos, dict->buf + copy_pos, + left); + dict->pos += left; + } + } + + // Update how full the dictionary is. + if (dict->full < dict->pos) + dict->full = dict->pos; + + return unlikely(*len != 0); +} + + +/// Puts one byte into the dictionary. Returns true if the dictionary was +/// already full and the byte couldn't be added. +static inline bool +dict_put(lzma_dict *dict, uint8_t byte) +{ + if (unlikely(dict->pos == dict->limit)) + return true; + + dict->buf[dict->pos++] = byte; + + if (dict->pos > dict->full) + dict->full = dict->pos; + + return false; +} + + +/// Copies arbitrary amount of data into the dictionary. +static inline void +dict_write(lzma_dict *restrict dict, const uint8_t *restrict in, + size_t *restrict in_pos, size_t in_size, + size_t *restrict left) +{ + // NOTE: If we are being given more data than the size of the + // dictionary, it could be possible to optimize the LZ decoder + // so that not everything needs to go through the dictionary. + // This shouldn't be very common thing in practice though, and + // the slowdown of one extra memcpy() isn't bad compared to how + // much time it would have taken if the data were compressed. + + if (in_size - *in_pos > *left) + in_size = *in_pos + *left; + + *left -= lzma_bufcpy(in, in_pos, in_size, + dict->buf, &dict->pos, dict->limit); + + if (dict->pos > dict->full) + dict->full = dict->pos; + + return; +} + + +static inline void +dict_reset(lzma_dict *dict) +{ + dict->need_reset = true; + return; +} + +#endif |