src/liblzma/lzma/lzma_encoder_private.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       lzma_encoder_private.h
   4 /// \brief      Private definitions for LZMA encoder
   5 //
   6 //  Copyright (C) 1999-2006 Igor Pavlov
   7 //  Copyright (C) 2007 Lasse Collin
   8 //
   9 //  This library is free software; you can redistribute it and/or
  10 //  modify it under the terms of the GNU Lesser General Public
  11 //  License as published by the Free Software Foundation; either
  12 //  version 2.1 of the License, or (at your option) any later version.
  13 //
  14 //  This library is distributed in the hope that it will be useful,
  15 //  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 //  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 //  Lesser General Public License for more details.
  18 //
  19 ///////////////////////////////////////////////////////////////////////////////
  20
  21 #ifndef LZMA_LZMA_ENCODER_PRIVATE_H
  22 #define LZMA_LZMA_ENCODER_PRIVATE_H
  23
  24 #include "lzma_encoder.h"
  25 #include "lzma_common.h"
  26 #include "lz_encoder.h"
  27 #include "range_encoder.h"
  28
  29 // We need space for about two encoding loops, because there is no check
  30 // for available buffer space before end of payload marker gets written.
  31 // 2*26 bytes should be enough for this... but Lasse isn't very sure about
  32 // the exact value. 64 bytes certainly is enough. :-)
  33 #if LZMA_LZ_TEMP_SIZE < 64
  34 #       error LZMA_LZ_TEMP_SIZE is too small.
  35 #endif
  36
  37
  38 #define move_pos(num) \
  39 do { \
  40         assert((int32_t)(num) >= 0); \
  41         if ((num) != 0) { \
  42                 coder->additional_offset += num; \
  43                 coder->lz.skip(&coder->lz, num); \
  44         } \
  45 } while (0)
  46
  47
  48 typedef struct {
  49         probability choice;
  50         probability choice2;
  51         probability low[POS_STATES_MAX][LEN_LOW_SYMBOLS];
  52         probability mid[POS_STATES_MAX][LEN_MID_SYMBOLS];
  53         probability high[LEN_HIGH_SYMBOLS];
  54
  55         uint32_t prices[POS_STATES_MAX][LEN_SYMBOLS];
  56         uint32_t table_size;
  57         uint32_t counters[POS_STATES_MAX];
  58
  59 } lzma_length_encoder;
  60
  61
  62 typedef struct {
  63         uint32_t state;
  64
  65         bool prev_1_is_char;
  66         bool prev_2;
  67
  68         uint32_t pos_prev_2;
  69         uint32_t back_prev_2;
  70
  71         uint32_t price;
  72         uint32_t pos_prev;  // pos_next;
  73         uint32_t back_prev;
  74
  75         uint32_t backs[4];
  76
  77 } lzma_optimal;
  78
  79
  80 struct lzma_coder_s {
  81         // Next coder in the chain
  82         lzma_next_coder next;
  83
  84         // In window and match finder
  85         lzma_lz_encoder lz;
  86
  87         // Range encoder
  88         lzma_range_encoder rc;
  89
  90         // State
  91         uint32_t state;
  92         uint8_t previous_byte;
  93         uint32_t rep_distances[REP_DISTANCES];
  94
  95         // Misc
  96         uint32_t match_distances[MATCH_MAX_LEN * 2 + 2 + 1];
  97         uint32_t num_distance_pairs;
  98         uint32_t additional_offset;
  99         uint32_t now_pos; // Lowest 32 bits are enough here.
 100         bool best_compression;           ///< True when LZMA_MODE_BEST is used
 101         bool is_initialized;
 102
 103         // Literal encoder
 104         lzma_literal_coder *literal_coder;
 105
 106         // Bit encoders
 107         probability is_match[STATES][POS_STATES_MAX];
 108         probability is_rep[STATES];
 109         probability is_rep0[STATES];
 110         probability is_rep1[STATES];
 111         probability is_rep2[STATES];
 112         probability is_rep0_long[STATES][POS_STATES_MAX];
 113         probability pos_encoders[FULL_DISTANCES - END_POS_MODEL_INDEX];
 114
 115         // Bit Tree Encoders
 116         probability pos_slot_encoder[LEN_TO_POS_STATES][1 << POS_SLOT_BITS];
 117         probability pos_align_encoder[1 << ALIGN_BITS];
 118
 119         // Length encoders
 120         lzma_length_encoder len_encoder;
 121         lzma_length_encoder rep_match_len_encoder;
 122
 123         // Optimal
 124         lzma_optimal optimum[OPTS];
 125         uint32_t optimum_end_index;
 126         uint32_t optimum_current_index;
 127         uint32_t longest_match_length;
 128         bool longest_match_was_found;
 129
 130         // Prices
 131         uint32_t pos_slot_prices[LEN_TO_POS_STATES][DIST_TABLE_SIZE_MAX];
 132         uint32_t distances_prices[LEN_TO_POS_STATES][FULL_DISTANCES];
 133         uint32_t align_prices[ALIGN_TABLE_SIZE];
 134         uint32_t align_price_count;
 135         uint32_t dist_table_size;
 136         uint32_t match_price_count;
 137
 138         // LZMA specific settings
 139         uint32_t dictionary_size;        ///< Size in bytes
 140         uint32_t fast_bytes;
 141         uint32_t pos_state_bits;
 142         uint32_t pos_mask;         ///< (1 << pos_state_bits) - 1
 143 };
 144
 145
 146 extern void lzma_length_encoder_update_table(lzma_length_encoder *lencoder,
 147                 const uint32_t pos_state);
 148
 149 extern bool lzma_lzma_encode(lzma_coder *coder, uint8_t *restrict out,
 150                 size_t *restrict out_pos, size_t out_size);
 151
 152 extern void lzma_get_optimum(lzma_coder *restrict coder,
 153                 uint32_t *restrict back_res, uint32_t *restrict len_res);
 154
 155 extern void lzma_get_optimum_fast(lzma_coder *restrict coder,
 156                 uint32_t *restrict back_res, uint32_t *restrict len_res);
 157
 158
 159 // NOTE: Don't add 'restrict'.
 160 static inline void
 161 lzma_read_match_distances(lzma_coder *coder,
 162                 uint32_t *len_res, uint32_t *num_distance_pairs)
 163 {
 164         *len_res = 0;
 165
 166         coder->lz.get_matches(&coder->lz, coder->match_distances);
 167
 168         *num_distance_pairs = coder->match_distances[0];
 169
 170         if (*num_distance_pairs > 0) {
 171                 *len_res = coder->match_distances[*num_distance_pairs - 1];
 172                 assert(*len_res <= MATCH_MAX_LEN);
 173
 174                 if (*len_res == coder->fast_bytes) {
 175                         uint32_t offset = *len_res - 1;
 176                         const uint32_t distance = coder->match_distances[
 177                                         *num_distance_pairs] + 1;
 178                         uint32_t limit = MATCH_MAX_LEN - *len_res;
 179
 180                         assert(offset + limit < coder->lz.keep_size_after);
 181                         assert(coder->lz.read_pos <= coder->lz.write_pos);
 182
 183                         // If we are close to end of the stream, we may need
 184                         // to limit the length of the match.
 185                         if (coder->lz.write_pos - coder->lz.read_pos
 186                                         < offset + limit)
 187                                 limit = coder->lz.write_pos
 188                                         - (coder->lz.read_pos + offset);
 189
 190                         offset += coder->lz.read_pos;
 191                         uint32_t i = 0;
 192                         while (i < limit && coder->lz.buffer[offset + i]
 193                                         == coder->lz.buffer[
 194                                                 offset + i - distance])
 195                                 ++i;
 196
 197                         *len_res += i;
 198                 }
 199         }
 200
 201         ++coder->additional_offset;
 202
 203         return;
 204 }
 205
 206 #endif