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   1 ///////////////////////////////////////////////////////////////////////////////
   2 //
   3 /// \file       lzma2_encoder.c
   4 /// \brief      LZMA2 encoder
   5 ///
   6 //  Authors:    Igor Pavlov
   7 //              Lasse Collin
   8 //
   9 //  This file has been put into the public domain.
  10 //  You can do whatever you want with this file.
  11 //
  12 ///////////////////////////////////////////////////////////////////////////////
  13
  14 #include "lz_encoder.h"
  15 #include "lzma_encoder.h"
  16 #include "fastpos.h"
  17 #include "lzma2_encoder.h"
  18
  19
  20 struct lzma_coder_s {
  21         enum {
  22                 SEQ_INIT,
  23                 SEQ_LZMA_ENCODE,
  24                 SEQ_LZMA_COPY,
  25                 SEQ_UNCOMPRESSED_HEADER,
  26                 SEQ_UNCOMPRESSED_COPY,
  27         } sequence;
  28
  29         /// LZMA encoder
  30         lzma_coder *lzma;
  31
  32         /// LZMA options currently in use.
  33         lzma_options_lzma opt_cur;
  34
  35         bool need_properties;
  36         bool need_state_reset;
  37         bool need_dictionary_reset;
  38
  39         /// Uncompressed size of a chunk
  40         size_t uncompressed_size;
  41
  42         /// Compressed size of a chunk (excluding headers); this is also used
  43         /// to indicate the end of buf[] in SEQ_LZMA_COPY.
  44         size_t compressed_size;
  45
  46         /// Read position in buf[]
  47         size_t buf_pos;
  48
  49         /// Buffer to hold the chunk header and LZMA compressed data
  50         uint8_t buf[LZMA2_HEADER_MAX + LZMA2_CHUNK_MAX];
  51 };
  52
  53
  54 static void
  55 lzma2_header_lzma(lzma_coder *coder)
  56 {
  57         assert(coder->uncompressed_size > 0);
  58         assert(coder->uncompressed_size <= LZMA2_UNCOMPRESSED_MAX);
  59         assert(coder->compressed_size > 0);
  60         assert(coder->compressed_size <= LZMA2_CHUNK_MAX);
  61
  62         size_t pos;
  63
  64         if (coder->need_properties) {
  65                 pos = 0;
  66
  67                 if (coder->need_dictionary_reset)
  68                         coder->buf[pos] = 0x80 + (3 << 5);
  69                 else
  70                         coder->buf[pos] = 0x80 + (2 << 5);
  71         } else {
  72                 pos = 1;
  73
  74                 if (coder->need_state_reset)
  75                         coder->buf[pos] = 0x80 + (1 << 5);
  76                 else
  77                         coder->buf[pos] = 0x80;
  78         }
  79
  80         // Set the start position for copying.
  81         coder->buf_pos = pos;
  82
  83         // Uncompressed size
  84         size_t size = coder->uncompressed_size - 1;
  85         coder->buf[pos++] += size >> 16;
  86         coder->buf[pos++] = (size >> 8) & 0xFF;
  87         coder->buf[pos++] = size & 0xFF;
  88
  89         // Compressed size
  90         size = coder->compressed_size - 1;
  91         coder->buf[pos++] = size >> 8;
  92         coder->buf[pos++] = size & 0xFF;
  93
  94         // Properties, if needed
  95         if (coder->need_properties)
  96                 lzma_lzma_lclppb_encode(&coder->opt_cur, coder->buf + pos);
  97
  98         coder->need_properties = false;
  99         coder->need_state_reset = false;
 100         coder->need_dictionary_reset = false;
 101
 102         // The copying code uses coder->compressed_size to indicate the end
 103         // of coder->buf[], so we need add the maximum size of the header here.
 104         coder->compressed_size += LZMA2_HEADER_MAX;
 105
 106         return;
 107 }
 108
 109
 110 static void
 111 lzma2_header_uncompressed(lzma_coder *coder)
 112 {
 113         assert(coder->uncompressed_size > 0);
 114         assert(coder->uncompressed_size <= LZMA2_CHUNK_MAX);
 115
 116         // If this is the first chunk, we need to include dictionary
 117         // reset indicator.
 118         if (coder->need_dictionary_reset)
 119                 coder->buf[0] = 1;
 120         else
 121                 coder->buf[0] = 2;
 122
 123         coder->need_dictionary_reset = false;
 124
 125         // "Compressed" size
 126         coder->buf[1] = (coder->uncompressed_size - 1) >> 8;
 127         coder->buf[2] = (coder->uncompressed_size - 1) & 0xFF;
 128
 129         // Set the start position for copying.
 130         coder->buf_pos = 0;
 131         return;
 132 }
 133
 134
 135 static lzma_ret
 136 lzma2_encode(lzma_coder *restrict coder, lzma_mf *restrict mf,
 137                 uint8_t *restrict out, size_t *restrict out_pos,
 138                 size_t out_size)
 139 {
 140         while (*out_pos < out_size)
 141         switch (coder->sequence) {
 142         case SEQ_INIT:
 143                 // If there's no input left and we are flushing or finishing,
 144                 // don't start a new chunk.
 145                 if (mf_unencoded(mf) == 0) {
 146                         // Write end of payload marker if finishing.
 147                         if (mf->action == LZMA_FINISH)
 148                                 out[(*out_pos)++] = 0;
 149
 150                         return mf->action == LZMA_RUN
 151                                         ? LZMA_OK : LZMA_STREAM_END;
 152                 }
 153
 154                 if (coder->need_state_reset)
 155                         return_if_error(lzma_lzma_encoder_reset(
 156                                         coder->lzma, &coder->opt_cur));
 157
 158                 coder->uncompressed_size = 0;
 159                 coder->compressed_size = 0;
 160                 coder->sequence = SEQ_LZMA_ENCODE;
 161
 162         // Fall through
 163
 164         case SEQ_LZMA_ENCODE: {
 165                 // Calculate how much more uncompressed data this chunk
 166                 // could accept.
 167                 const uint32_t left = LZMA2_UNCOMPRESSED_MAX
 168                                 - coder->uncompressed_size;
 169                 uint32_t limit;
 170
 171                 if (left < mf->match_len_max) {
 172                         // Must flush immediately since the next LZMA symbol
 173                         // could make the uncompressed size of the chunk too
 174                         // big.
 175                         limit = 0;
 176                 } else {
 177                         // Calculate maximum read_limit that is OK from point
 178                         // of view of LZMA2 chunk size.
 179                         limit = mf->read_pos - mf->read_ahead
 180                                         + left - mf->match_len_max;
 181                 }
 182
 183                 // Save the start position so that we can update
 184                 // coder->uncompressed_size.
 185                 const uint32_t read_start = mf->read_pos - mf->read_ahead;
 186
 187                 // Call the LZMA encoder until the chunk is finished.
 188                 const lzma_ret ret = lzma_lzma_encode(coder->lzma, mf,
 189                                 coder->buf + LZMA2_HEADER_MAX,
 190                                 &coder->compressed_size,
 191                                 LZMA2_CHUNK_MAX, limit);
 192
 193                 coder->uncompressed_size += mf->read_pos - mf->read_ahead
 194                                 - read_start;
 195
 196                 assert(coder->compressed_size <= LZMA2_CHUNK_MAX);
 197                 assert(coder->uncompressed_size <= LZMA2_UNCOMPRESSED_MAX);
 198
 199                 if (ret != LZMA_STREAM_END)
 200                         return LZMA_OK;
 201
 202                 // See if the chunk compressed. If it didn't, we encode it
 203                 // as uncompressed chunk. This saves a few bytes of space
 204                 // and makes decoding faster.
 205                 if (coder->compressed_size >= coder->uncompressed_size) {
 206                         coder->uncompressed_size += mf->read_ahead;
 207                         assert(coder->uncompressed_size
 208                                         <= LZMA2_UNCOMPRESSED_MAX);
 209                         mf->read_ahead = 0;
 210                         lzma2_header_uncompressed(coder);
 211                         coder->need_state_reset = true;
 212                         coder->sequence = SEQ_UNCOMPRESSED_HEADER;
 213                         break;
 214                 }
 215
 216                 // The chunk did compress at least by one byte, so we store
 217                 // the chunk as LZMA.
 218                 lzma2_header_lzma(coder);
 219
 220                 coder->sequence = SEQ_LZMA_COPY;
 221         }
 222
 223         // Fall through
 224
 225         case SEQ_LZMA_COPY:
 226                 // Copy the compressed chunk along its headers to the
 227                 // output buffer.
 228                 lzma_bufcpy(coder->buf, &coder->buf_pos,
 229                                 coder->compressed_size,
 230                                 out, out_pos, out_size);
 231                 if (coder->buf_pos != coder->compressed_size)
 232                         return LZMA_OK;
 233
 234                 coder->sequence = SEQ_INIT;
 235                 break;
 236
 237         case SEQ_UNCOMPRESSED_HEADER:
 238                 // Copy the three-byte header to indicate uncompressed chunk.
 239                 lzma_bufcpy(coder->buf, &coder->buf_pos,
 240                                 LZMA2_HEADER_UNCOMPRESSED,
 241                                 out, out_pos, out_size);
 242                 if (coder->buf_pos != LZMA2_HEADER_UNCOMPRESSED)
 243                         return LZMA_OK;
 244
 245                 coder->sequence = SEQ_UNCOMPRESSED_COPY;
 246
 247         // Fall through
 248
 249         case SEQ_UNCOMPRESSED_COPY:
 250                 // Copy the uncompressed data as is from the dictionary
 251                 // to the output buffer.
 252                 mf_read(mf, out, out_pos, out_size, &coder->uncompressed_size);
 253                 if (coder->uncompressed_size != 0)
 254                         return LZMA_OK;
 255
 256                 coder->sequence = SEQ_INIT;
 257                 break;
 258         }
 259
 260         return LZMA_OK;
 261 }
 262
 263
 264 static void
 265 lzma2_encoder_end(lzma_coder *coder, const lzma_allocator *allocator)
 266 {
 267         lzma_free(coder->lzma, allocator);
 268         lzma_free(coder, allocator);
 269         return;
 270 }
 271
 272
 273 static lzma_ret
 274 lzma2_encoder_options_update(lzma_coder *coder, const lzma_filter *filter)
 275 {
 276         // New options can be set only when there is no incomplete chunk.
 277         // This is the case at the beginning of the raw stream and right
 278         // after LZMA_SYNC_FLUSH.
 279         if (filter->options == NULL || coder->sequence != SEQ_INIT)
 280                 return LZMA_PROG_ERROR;
 281
 282         // Look if there are new options. At least for now,
 283         // only lc/lp/pb can be changed.
 284         const lzma_options_lzma *opt = filter->options;
 285         if (coder->opt_cur.lc != opt->lc || coder->opt_cur.lp != opt->lp
 286                         || coder->opt_cur.pb != opt->pb) {
 287                 // Validate the options.
 288                 if (opt->lc > LZMA_LCLP_MAX || opt->lp > LZMA_LCLP_MAX
 289                                 || opt->lc + opt->lp > LZMA_LCLP_MAX
 290                                 || opt->pb > LZMA_PB_MAX)
 291                         return LZMA_OPTIONS_ERROR;
 292
 293                 // The new options will be used when the encoder starts
 294                 // a new LZMA2 chunk.
 295                 coder->opt_cur.lc = opt->lc;
 296                 coder->opt_cur.lp = opt->lp;
 297                 coder->opt_cur.pb = opt->pb;
 298                 coder->need_properties = true;
 299                 coder->need_state_reset = true;
 300         }
 301
 302         return LZMA_OK;
 303 }
 304
 305
 306 static lzma_ret
 307 lzma2_encoder_init(lzma_lz_encoder *lz, const lzma_allocator *allocator,
 308                 const void *options, lzma_lz_options *lz_options)
 309 {
 310         if (options == NULL)
 311                 return LZMA_PROG_ERROR;
 312
 313         if (lz->coder == NULL) {
 314                 lz->coder = lzma_alloc(sizeof(lzma_coder), allocator);
 315                 if (lz->coder == NULL)
 316                         return LZMA_MEM_ERROR;
 317
 318                 lz->code = &lzma2_encode;
 319                 lz->end = &lzma2_encoder_end;
 320                 lz->options_update = &lzma2_encoder_options_update;
 321
 322                 lz->coder->lzma = NULL;
 323         }
 324
 325         lz->coder->opt_cur = *(const lzma_options_lzma *)(options);
 326
 327         lz->coder->sequence = SEQ_INIT;
 328         lz->coder->need_properties = true;
 329         lz->coder->need_state_reset = false;
 330         lz->coder->need_dictionary_reset
 331                         = lz->coder->opt_cur.preset_dict == NULL
 332                         || lz->coder->opt_cur.preset_dict_size == 0;
 333
 334         // Initialize LZMA encoder
 335         return_if_error(lzma_lzma_encoder_create(&lz->coder->lzma, allocator,
 336                         &lz->coder->opt_cur, lz_options));
 337
 338         // Make sure that we will always have enough history available in
 339         // case we need to use uncompressed chunks. They are used when the
 340         // compressed size of a chunk is not smaller than the uncompressed
 341         // size, so we need to have at least LZMA2_COMPRESSED_MAX bytes
 342         // history available.
 343         if (lz_options->before_size + lz_options->dict_size < LZMA2_CHUNK_MAX)
 344                 lz_options->before_size
 345                                 = LZMA2_CHUNK_MAX - lz_options->dict_size;
 346
 347         return LZMA_OK;
 348 }
 349
 350
 351 extern lzma_ret
 352 lzma_lzma2_encoder_init(lzma_next_coder *next, const lzma_allocator *allocator,
 353                 const lzma_filter_info *filters)
 354 {
 355         return lzma_lz_encoder_init(
 356                         next, allocator, filters, &lzma2_encoder_init);
 357 }
 358
 359
 360 extern uint64_t
 361 lzma_lzma2_encoder_memusage(const void *options)
 362 {
 363         const uint64_t lzma_mem = lzma_lzma_encoder_memusage(options);
 364         if (lzma_mem == UINT64_MAX)
 365                 return UINT64_MAX;
 366
 367         return sizeof(lzma_coder) + lzma_mem;
 368 }
 369
 370
 371 extern lzma_ret
 372 lzma_lzma2_props_encode(const void *options, uint8_t *out)
 373 {
 374         const lzma_options_lzma *const opt = options;
 375         uint32_t d = my_max(opt->dict_size, LZMA_DICT_SIZE_MIN);
 376
 377         // Round up to the next 2^n - 1 or 2^n + 2^(n - 1) - 1 depending
 378         // on which one is the next:
 379         --d;
 380         d |= d >> 2;
 381         d |= d >> 3;
 382         d |= d >> 4;
 383         d |= d >> 8;
 384         d |= d >> 16;
 385
 386         // Get the highest two bits using the proper encoding:
 387         if (d == UINT32_MAX)
 388                 out[0] = 40;
 389         else
 390                 out[0] = get_dist_slot(d + 1) - 24;
 391
 392         return LZMA_OK;
 393 }
 394
 395
 396 extern uint64_t
 397 lzma_lzma2_block_size(const void *options)
 398 {
 399         const lzma_options_lzma *const opt = options;
 400
 401         // Use at least 1 MiB to keep compression ratio better.
 402         return my_max((uint64_t)(opt->dict_size) * 3, UINT64_C(1) << 20);
 403 }