src/liblzma/lzma/lzma_encoder_init.c

   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       lzma_encoder_init.c
   4 /// \brief      Creating, resetting and destroying the 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 #include "lzma_encoder_private.h"
  22
  23
  24 /// \brief      Initializes the length encoder
  25 static void
  26 length_encoder_reset(lzma_length_encoder *lencoder,
  27                 const uint32_t num_pos_states, const uint32_t table_size)
  28 {
  29         // NLength::CPriceTableEncoder::SetTableSize()
  30         lencoder->table_size = table_size;
  31
  32         // NLength::CEncoder::Init()
  33         bit_reset(lencoder->choice);
  34         bit_reset(lencoder->choice2);
  35
  36         for (size_t pos_state = 0; pos_state < num_pos_states; ++pos_state) {
  37                 bittree_reset(lencoder->low[pos_state], LEN_LOW_BITS);
  38                 bittree_reset(lencoder->mid[pos_state], LEN_MID_BITS);
  39         }
  40
  41         bittree_reset(lencoder->high, LEN_HIGH_BITS);
  42
  43         // NLength::CPriceTableEncoder::UpdateTables()
  44         for (size_t pos_state = 0; pos_state < num_pos_states; ++pos_state)
  45                 lzma_length_encoder_update_table(lencoder, pos_state);
  46
  47         return;
  48 }
  49
  50
  51 static void
  52 lzma_lzma_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
  53 {
  54         lzma_lz_encoder_end(&coder->lz, allocator);
  55         lzma_literal_end(&coder->literal_coder, allocator);
  56         lzma_free(coder, allocator);
  57         return;
  58 }
  59
  60
  61 extern lzma_ret
  62 lzma_lzma_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
  63                 const lzma_filter_info *filters)
  64 {
  65         if (next->coder == NULL) {
  66                 next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
  67                 if (next->coder == NULL)
  68                         return LZMA_MEM_ERROR;
  69
  70                 next->coder->next = LZMA_NEXT_CODER_INIT;
  71                 next->coder->lz = LZMA_LZ_ENCODER_INIT;
  72                 next->coder->literal_coder = NULL;
  73         }
  74
  75         // Validate options that aren't validated elsewhere.
  76         const lzma_options_lzma *options = filters[0].options;
  77         if (options->pos_bits > LZMA_POS_BITS_MAX
  78                         || options->fast_bytes < LZMA_FAST_BYTES_MIN
  79                         || options->fast_bytes > LZMA_FAST_BYTES_MAX) {
  80                 lzma_lzma_encoder_end(next->coder, allocator);
  81                 return LZMA_HEADER_ERROR;
  82         }
  83
  84         // Set compression mode.
  85         switch (options->mode) {
  86                 case LZMA_MODE_FAST:
  87                         next->coder->best_compression = false;
  88                         break;
  89
  90                 case LZMA_MODE_BEST:
  91                         next->coder->best_compression = true;
  92                         break;
  93
  94                 default:
  95                         lzma_lzma_encoder_end(next->coder, allocator);
  96                         return LZMA_HEADER_ERROR;
  97         }
  98
  99         // Initialize literal coder.
 100         {
 101                 const lzma_ret ret = lzma_literal_init(
 102                                 &next->coder->literal_coder, allocator,
 103                                 options->literal_context_bits,
 104                                 options->literal_pos_bits);
 105                 if (ret != LZMA_OK) {
 106                         lzma_lzma_encoder_end(next->coder, allocator);
 107                         return ret;
 108                 }
 109         }
 110
 111         // Initialize LZ encoder.
 112         {
 113                 const lzma_ret ret = lzma_lz_encoder_reset(
 114                                 &next->coder->lz, allocator, &lzma_lzma_encode,
 115                                 filters[0].uncompressed_size,
 116                                 options->dictionary_size, OPTS,
 117                                 options->fast_bytes, MATCH_MAX_LEN + 1 + OPTS,
 118                                 options->match_finder,
 119                                 options->match_finder_cycles,
 120                                 options->preset_dictionary,
 121                                 options->preset_dictionary_size);
 122                 if (ret != LZMA_OK) {
 123                         lzma_lzma_encoder_end(next->coder, allocator);
 124                         return ret;
 125                 }
 126         }
 127
 128         // Set dist_table_size.
 129         {
 130                 // Round the dictionary size up to next 2^n.
 131                 uint32_t log_size;
 132                 for (log_size = 0; (UINT32_C(1) << log_size)
 133                                 < options->dictionary_size; ++log_size) ;
 134
 135                 next->coder->dist_table_size = log_size * 2;
 136         }
 137
 138         // Misc FIXME desc
 139         next->coder->dictionary_size = options->dictionary_size;
 140         next->coder->pos_mask = (1U << options->pos_bits) - 1;
 141         next->coder->fast_bytes = options->fast_bytes;
 142
 143         // Range coder
 144         rc_reset(next->coder->rc);
 145
 146         // State
 147         next->coder->state = 0;
 148         next->coder->previous_byte = 0;
 149         for (size_t i = 0; i < REP_DISTANCES; ++i)
 150                 next->coder->rep_distances[i] = 0;
 151
 152         // Bit encoders
 153         for (size_t i = 0; i < STATES; ++i) {
 154                 for (size_t j = 0; j <= next->coder->pos_mask; ++j) {
 155                         bit_reset(next->coder->is_match[i][j]);
 156                         bit_reset(next->coder->is_rep0_long[i][j]);
 157                 }
 158
 159                 bit_reset(next->coder->is_rep[i]);
 160                 bit_reset(next->coder->is_rep0[i]);
 161                 bit_reset(next->coder->is_rep1[i]);
 162                 bit_reset(next->coder->is_rep2[i]);
 163         }
 164
 165         for (size_t i = 0; i < FULL_DISTANCES - END_POS_MODEL_INDEX; ++i)
 166                 bit_reset(next->coder->pos_encoders[i]);
 167
 168         // Bit tree encoders
 169         for (size_t i = 0; i < LEN_TO_POS_STATES; ++i)
 170                 bittree_reset(next->coder->pos_slot_encoder[i], POS_SLOT_BITS);
 171
 172         bittree_reset(next->coder->pos_align_encoder, ALIGN_BITS);
 173
 174         // Length encoders
 175         length_encoder_reset(&next->coder->len_encoder, 1U << options->pos_bits,
 176                         options->fast_bytes + 1 - MATCH_MIN_LEN);
 177
 178         length_encoder_reset(&next->coder->rep_match_len_encoder,
 179                         1U << options->pos_bits,
 180                         next->coder->fast_bytes + 1 - MATCH_MIN_LEN);
 181
 182         // Misc
 183         next->coder->longest_match_was_found = false;
 184         next->coder->optimum_end_index = 0;
 185         next->coder->optimum_current_index = 0;
 186         next->coder->additional_offset = 0;
 187
 188         next->coder->now_pos = 0;
 189         next->coder->is_initialized = false;
 190
 191         // Initialize the next decoder in the chain, if any.
 192         {
 193                 const lzma_ret ret = lzma_next_filter_init(&next->coder->next,
 194                                 allocator, filters + 1);
 195                 if (ret != LZMA_OK) {
 196                         lzma_lzma_encoder_end(next->coder, allocator);
 197                         return ret;
 198                 }
 199         }
 200
 201         // Initialization successful. Set the function pointers.
 202         next->code = &lzma_lz_encode;
 203         next->end = &lzma_lzma_encoder_end;
 204
 205         return LZMA_OK;
 206 }
 207
 208
 209 extern bool
 210 lzma_lzma_encode_properties(const lzma_options_lzma *options, uint8_t *byte)
 211 {
 212         if (options->literal_context_bits > LZMA_LITERAL_CONTEXT_BITS_MAX
 213                         || options->literal_pos_bits
 214                                 > LZMA_LITERAL_POS_BITS_MAX
 215                         || options->pos_bits > LZMA_POS_BITS_MAX)
 216                 return true;
 217
 218         *byte = (options->pos_bits * 5 + options->literal_pos_bits) * 9
 219                         + options->literal_context_bits;
 220         assert(*byte <= (4 * 5 + 4) * 9 + 8);
 221
 222         return false;
 223 }