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, 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, 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, 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_pos_slot(d + 1) - 24; 391 392 return LZMA_OK; 393 } 394