1 /* deflate.c -- compress data using the deflation algorithm 2 * Copyright (C) 1995-2004 Jean-loup Gailly. 3 * For conditions of distribution and use, see copyright notice in zlib.h 4 */ 5 6 /* 7 * ALGORITHM 8 * 9 * The "deflation" process depends on being able to identify portions 10 * of the input text which are identical to earlier input (within a 11 * sliding window trailing behind the input currently being processed). 12 * 13 * The most straightforward technique turns out to be the fastest for 14 * most input files: try all possible matches and select the longest. 15 * The key feature of this algorithm is that insertions into the string 16 * dictionary are very simple and thus fast, and deletions are avoided 17 * completely. Insertions are performed at each input character, whereas 18 * string matches are performed only when the previous match ends. So it 19 * is preferable to spend more time in matches to allow very fast string 20 * insertions and avoid deletions. The matching algorithm for small 21 * strings is inspired from that of Rabin & Karp. A brute force approach 22 * is used to find longer strings when a small match has been found. 23 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze 24 * (by Leonid Broukhis). 25 * A previous version of this file used a more sophisticated algorithm 26 * (by Fiala and Greene) which is guaranteed to run in linear amortized 27 * time, but has a larger average cost, uses more memory and is patented. 28 * However the F&G algorithm may be faster for some highly redundant 29 * files if the parameter max_chain_length (described below) is too large. 30 * 31 * ACKNOWLEDGEMENTS 32 * 33 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and 34 * I found it in 'freeze' written by Leonid Broukhis. 35 * Thanks to many people for bug reports and testing. 36 * 37 * REFERENCES 38 * 39 * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". 40 * Available in http://www.ietf.org/rfc/rfc1951.txt 41 * 42 * A description of the Rabin and Karp algorithm is given in the book 43 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. 44 * 45 * Fiala,E.R., and Greene,D.H. 46 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 47 * 48 */ 49 50 /* @(#) $Id$ */ 51 52 #include "deflate.h" 53 54 const char deflate_copyright[] = 55 " deflate 1.2.2 Copyright 1995-2004 Jean-loup Gailly "; 56 /* 57 If you use the zlib library in a product, an acknowledgment is welcome 58 in the documentation of your product. If for some reason you cannot 59 include such an acknowledgment, I would appreciate that you keep this 60 copyright string in the executable of your product. 61 */ 62 63 /* =========================================================================== 64 * Function prototypes. 65 */ 66 typedef enum { 67 need_more, /* block not completed, need more input or more output */ 68 block_done, /* block flush performed */ 69 finish_started, /* finish started, need only more output at next deflate */ 70 finish_done /* finish done, accept no more input or output */ 71 } block_state; 72 73 typedef block_state (*compress_func) OF((deflate_state *s, int flush)); 74 /* Compression function. Returns the block state after the call. */ 75 76 local void fill_window OF((deflate_state *s)); 77 local block_state deflate_stored OF((deflate_state *s, int flush)); 78 local block_state deflate_fast OF((deflate_state *s, int flush)); 79 #ifndef FASTEST 80 local block_state deflate_slow OF((deflate_state *s, int flush)); 81 #endif 82 local void lm_init OF((deflate_state *s)); 83 local void putShortMSB OF((deflate_state *s, uInt b)); 84 local void flush_pending OF((z_streamp strm)); 85 local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size)); 86 #ifndef FASTEST 87 #ifdef ASMV 88 void match_init OF((void)); /* asm code initialization */ 89 uInt longest_match OF((deflate_state *s, IPos cur_match)); 90 #else 91 local uInt longest_match OF((deflate_state *s, IPos cur_match)); 92 #endif 93 #endif 94 local uInt longest_match_fast OF((deflate_state *s, IPos cur_match)); 95 96 #ifdef DEBUG 97 local void check_match OF((deflate_state *s, IPos start, IPos match, 98 int length)); 99 #endif 100 101 /* =========================================================================== 102 * Local data 103 */ 104 105 #define NIL 0 106 /* Tail of hash chains */ 107 108 #ifndef TOO_FAR 109 # define TOO_FAR 4096 110 #endif 111 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */ 112 113 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1) 114 /* Minimum amount of lookahead, except at the end of the input file. 115 * See deflate.c for comments about the MIN_MATCH+1. 116 */ 117 118 /* Values for max_lazy_match, good_match and max_chain_length, depending on 119 * the desired pack level (0..9). The values given below have been tuned to 120 * exclude worst case performance for pathological files. Better values may be 121 * found for specific files. 122 */ 123 typedef struct config_s { 124 ush good_length; /* reduce lazy search above this match length */ 125 ush max_lazy; /* do not perform lazy search above this match length */ 126 ush nice_length; /* quit search above this match length */ 127 ush max_chain; 128 compress_func func; 129 } config; 130 131 #ifdef FASTEST 132 local const config configuration_table[2] = { 133 /* good lazy nice chain */ 134 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ 135 /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */ 136 #else 137 local const config configuration_table[10] = { 138 /* good lazy nice chain */ 139 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ 140 /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */ 141 /* 2 */ {4, 5, 16, 8, deflate_fast}, 142 /* 3 */ {4, 6, 32, 32, deflate_fast}, 143 144 /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ 145 /* 5 */ {8, 16, 32, 32, deflate_slow}, 146 /* 6 */ {8, 16, 128, 128, deflate_slow}, 147 /* 7 */ {8, 32, 128, 256, deflate_slow}, 148 /* 8 */ {32, 128, 258, 1024, deflate_slow}, 149 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */ 150 #endif 151 152 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 153 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different 154 * meaning. 155 */ 156 157 #define EQUAL 0 158 /* result of memcmp for equal strings */ 159 160 #ifndef NO_DUMMY_DECL 161 struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ 162 #endif 163 164 /* =========================================================================== 165 * Update a hash value with the given input byte 166 * IN assertion: all calls to to UPDATE_HASH are made with consecutive 167 * input characters, so that a running hash key can be computed from the 168 * previous key instead of complete recalculation each time. 169 */ 170 #define UPDATE_HASH(s,h,c) (h = (((h)<hash_shift) ^ (c)) & s->hash_mask) 171 172 173 /* =========================================================================== 174 * Insert string str in the dictionary and set match_head to the previous head 175 * of the hash chain (the most recent string with same hash key). Return 176 * the previous length of the hash chain. 177 * If this file is compiled with -DFASTEST, the compression level is forced 178 * to 1, and no hash chains are maintained. 179 * IN assertion: all calls to to INSERT_STRING are made with consecutive 180 * input characters and the first MIN_MATCH bytes of str are valid 181 * (except for the last MIN_MATCH-1 bytes of the input file). 182 */ 183 #ifdef FASTEST 184 #define INSERT_STRING(s, str, match_head) \ 185 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ 186 match_head = s->head[s->ins_h], \ 187 s->head[s->ins_h] = (Pos)(str)) 188 #else 189 #define INSERT_STRING(s, str, match_head) \ 190 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ 191 match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \ 192 s->head[s->ins_h] = (Pos)(str)) 193 #endif 194 195 /* =========================================================================== 196 * Initialize the hash table (avoiding 64K overflow for 16 bit systems). 197 * prev[] will be initialized on the fly. 198 */ 199 #define CLEAR_HASH(s) \ 200 s->head[s->hash_size-1] = NIL; \ 201 zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); 202 203 /* ========================================================================= */ 204 int ZEXPORT deflateInit_(strm, level, version, stream_size) 205 z_streamp strm; 206 int level; 207 const char *version; 208 int stream_size; 209 ###### { 210 ###### return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, 211 Z_DEFAULT_STRATEGY, version, stream_size); 212 /* To do: ignore strm->next_in if we use it as window */ 213 } 214 215 /* ========================================================================= */ 216 int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, 217 version, stream_size) 218 z_streamp strm; 219 int level; 220 int method; 221 int windowBits; 222 int memLevel; 223 int strategy; 224 const char *version; 225 int stream_size; 226 71 { 227 71 deflate_state *s; 228 71 int wrap = 1; 229 71 static const char my_version[] = ZLIB_VERSION; 230 231 71 ushf *overlay; 232 /* We overlay pending_buf and d_buf+l_buf. This works since the average 233 * output size for (length,distance) codes is <= 24 bits. 234 */ 235 236 71 if (version == Z_NULL || version[0] != my_version[0] || 237 stream_size != sizeof(z_stream)) { 238 ###### return Z_VERSION_ERROR; 239 } 240 71 if (strm == Z_NULL) return Z_STREAM_ERROR; 241 242 71 strm->msg = Z_NULL; 243 71 if (strm->zalloc == (alloc_func)0) { 244 71 strm->zalloc = zcalloc; 245 71 strm->opaque = (voidpf)0; 246 } 247 71 if (strm->zfree == (free_func)0) strm->zfree = zcfree; 248 249 #ifdef FASTEST 250 if (level != 0) level = 1; 251 #else 252 71 if (level == Z_DEFAULT_COMPRESSION) level = 6; 253 #endif 254 255 71 if (windowBits < 0) { /* suppress zlib wrapper */ 256 29 wrap = 0; 257 29 windowBits = -windowBits; 258 } 259 #ifdef GZIP 260 42 else if (windowBits > 15) { 261 ###### wrap = 2; /* write gzip wrapper instead */ 262 ###### windowBits -= 16; 263 } 264 #endif 265 71 if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || 266 windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || 267 strategy < 0 || strategy > Z_RLE) { 268 1 return Z_STREAM_ERROR; 269 } 270 70 if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ 271 70 s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); 272 70 if (s == Z_NULL) return Z_MEM_ERROR; 273 70 strm->state = (struct internal_state FAR *)s; 274 70 s->strm = strm; 275 276 70 s->wrap = wrap; 277 70 s->w_bits = windowBits; 278 70 s->w_size = 1 << s->w_bits; 279 70 s->w_mask = s->w_size - 1; 280 281 70 s->hash_bits = memLevel + 7; 282 70 s->hash_size = 1 << s->hash_bits; 283 70 s->hash_mask = s->hash_size - 1; 284 70 s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); 285 286 70 s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); 287 70 s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); 288 70 s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); 289 290 70 s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ 291 292 70 overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); 293 70 s->pending_buf = (uchf *) overlay; 294 70 s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); 295 296 70 if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || 297 s->pending_buf == Z_NULL) { 298 ###### s->status = FINISH_STATE; 299 ###### strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); 300 ###### deflateEnd (strm); 301 ###### return Z_MEM_ERROR; 302 } 303 70 s->d_buf = overlay + s->lit_bufsize/sizeof(ush); 304 70 s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; 305 306 70 s->level = level; 307 70 s->strategy = strategy; 308 70 s->method = (Byte)method; 309 310 70 return deflateReset(strm); 311 } 312 313 /* ========================================================================= */ 314 int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) 315 z_streamp strm; 316 const Bytef *dictionary; 317 uInt dictLength; 318 1 { 319 1 deflate_state *s; 320 1 uInt length = dictLength; 321 1 uInt n; 322 1 IPos hash_head = 0; 323 324 1 if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || 325 strm->state->wrap == 2 || 326 (strm->state->wrap == 1 && strm->state->status != INIT_STATE)) 327 ###### return Z_STREAM_ERROR; 328 329 1 s = strm->state; 330 1 if (s->wrap) 331 1 strm->adler = adler32(strm->adler, dictionary, dictLength); 332 333 1 if (length < MIN_MATCH) return Z_OK; 334 1 if (length > MAX_DIST(s)) { 335 ###### length = MAX_DIST(s); 336 #ifndef USE_DICT_HEAD 337 ###### dictionary += dictLength - length; /* use the tail of the dictionary */ 338 #endif 339 } 340 1 zmemcpy(s->window, dictionary, length); 341 1 s->strstart = length; 342 1 s->block_start = (long)length; 343 344 /* Insert all strings in the hash table (except for the last two bytes). 345 * s->lookahead stays null, so s->ins_h will be recomputed at the next 346 * call of fill_window. 347 */ 348 1 s->ins_h = s->window[0]; 349 1 UPDATE_HASH(s, s->ins_h, s->window[1]); 350 4 for (n = 0; n <= length - MIN_MATCH; n++) { 351 3 INSERT_STRING(s, n, hash_head); 352 } 353 1 if (hash_head) hash_head = 0; /* to make compiler happy */ 354 1 return Z_OK; 355 } 356 357 /* ========================================================================= */ 358 int ZEXPORT deflateReset (strm) 359 z_streamp strm; 360 70 { 361 70 deflate_state *s; 362 363 70 if (strm == Z_NULL || strm->state == Z_NULL || 364 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) { 365 ###### return Z_STREAM_ERROR; 366 } 367 368 70 strm->total_in = strm->total_out = 0; 369 70 strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ 370 70 strm->data_type = Z_UNKNOWN; 371 372 70 s = (deflate_state *)strm->state; 373 70 s->pending = 0; 374 70 s->pending_out = s->pending_buf; 375 376 70 if (s->wrap < 0) { 377 ###### s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ 378 } 379 70 s->status = s->wrap ? INIT_STATE : BUSY_STATE; 380 70 strm->adler = 381 #ifdef GZIP 382 s->wrap == 2 ? crc32(0L, Z_NULL, 0) : 383 #endif 384 adler32(0L, Z_NULL, 0); 385 70 s->last_flush = Z_NO_FLUSH; 386 387 70 _tr_init(s); 388 70 lm_init(s); 389 390 70 return Z_OK; 391 } 392 393 /* ========================================================================= */ 394 int ZEXPORT deflatePrime (strm, bits, value) 395 z_streamp strm; 396 int bits; 397 int value; 398 ###### { 399 ###### if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 400 ###### strm->state->bi_valid = bits; 401 ###### strm->state->bi_buf = (ush)(value & ((1 << bits) - 1)); 402 ###### return Z_OK; 403 } 404 405 /* ========================================================================= */ 406 int ZEXPORT deflateParams(strm, level, strategy) 407 z_streamp strm; 408 int level; 409 int strategy; 410 4 { 411 4 deflate_state *s; 412 4 compress_func func; 413 4 int err = Z_OK; 414 415 4 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 416 4 s = strm->state; 417 418 #ifdef FASTEST 419 if (level != 0) level = 1; 420 #else 421 4 if (level == Z_DEFAULT_COMPRESSION) level = 6; 422 #endif 423 4 if (level < 0 || level > 9 || strategy < 0 || strategy > Z_RLE) { 424 ###### return Z_STREAM_ERROR; 425 } 426 4 func = configuration_table[s->level].func; 427 428 4 if (func != configuration_table[level].func && strm->total_in != 0) { 429 /* Flush the last buffer: */ 430 3 err = deflate(strm, Z_PARTIAL_FLUSH); 431 } 432 4 if (s->level != level) { 433 3 s->level = level; 434 3 s->max_lazy_match = configuration_table[level].max_lazy; 435 3 s->good_match = configuration_table[level].good_length; 436 3 s->nice_match = configuration_table[level].nice_length; 437 3 s->max_chain_length = configuration_table[level].max_chain; 438 } 439 4 s->strategy = strategy; 440 4 return err; 441 } 442 443 /* ========================================================================= 444 * For the default windowBits of 15 and memLevel of 8, this function returns 445 * a close to exact, as well as small, upper bound on the compressed size. 446 * They are coded as constants here for a reason--if the #define's are 447 * changed, then this function needs to be changed as well. The return 448 * value for 15 and 8 only works for those exact settings. 449 * 450 * For any setting other than those defaults for windowBits and memLevel, 451 * the value returned is a conservative worst case for the maximum expansion 452 * resulting from using fixed blocks instead of stored blocks, which deflate 453 * can emit on compressed data for some combinations of the parameters. 454 * 455 * This function could be more sophisticated to provide closer upper bounds 456 * for every combination of windowBits and memLevel, as well as wrap. 457 * But even the conservative upper bound of about 14% expansion does not 458 * seem onerous for output buffer allocation. 459 */ 460 uLong ZEXPORT deflateBound(strm, sourceLen) 461 z_streamp strm; 462 uLong sourceLen; 463 ###### { 464 ###### deflate_state *s; 465 ###### uLong destLen; 466 467 /* conservative upper bound */ 468 ###### destLen = sourceLen + 469 ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11; 470 471 /* if can't get parameters, return conservative bound */ 472 ###### if (strm == Z_NULL || strm->state == Z_NULL) 473 ###### return destLen; 474 475 /* if not default parameters, return conservative bound */ 476 ###### s = strm->state; 477 ###### if (s->w_bits != 15 || s->hash_bits != 8 + 7) 478 ###### return destLen; 479 480 /* default settings: return tight bound for that case */ 481 ###### return compressBound(sourceLen); 482 } 483 484 /* ========================================================================= 485 * Put a short in the pending buffer. The 16-bit value is put in MSB order. 486 * IN assertion: the stream state is correct and there is enough room in 487 * pending_buf. 488 */ 489 local void putShortMSB (s, b) 490 deflate_state *s; 491 uInt b; 492 125 { 493 125 put_byte(s, (Byte)(b >> 8)); 494 125 put_byte(s, (Byte)(b & 0xff)); 495 } 496 497 /* ========================================================================= 498 * Flush as much pending output as possible. All deflate() output goes 499 * through this function so some applications may wish to modify it 500 * to avoid allocating a large strm->next_out buffer and copying into it. 501 * (See also read_buf()). 502 */ 503 local void flush_pending(strm) 504 z_streamp strm; 505 178 { 506 178 unsigned len = strm->state->pending; 507 508 178 if (len > strm->avail_out) len = strm->avail_out; 509 178 if (len == 0) return; 510 511 178 zmemcpy(strm->next_out, strm->state->pending_out, len); 512 178 strm->next_out += len; 513 178 strm->state->pending_out += len; 514 178 strm->total_out += len; 515 178 strm->avail_out -= len; 516 178 strm->state->pending -= len; 517 178 if (strm->state->pending == 0) { 518 160 strm->state->pending_out = strm->state->pending_buf; 519 } 520 } 521 522 /* ========================================================================= */ 523 int ZEXPORT deflate (strm, flush) 524 z_streamp strm; 525 int flush; 526 287 { 527 287 int old_flush; /* value of flush param for previous deflate call */ 528 287 deflate_state *s; 529 530 287 if (strm == Z_NULL || strm->state == Z_NULL || 531 flush > Z_FINISH || flush < 0) { 532 ###### return Z_STREAM_ERROR; 533 } 534 287 s = strm->state; 535 536 287 if (strm->next_out == Z_NULL || 537 (strm->next_in == Z_NULL && strm->avail_in != 0) || 538 (s->status == FINISH_STATE && flush != Z_FINISH)) { 539 ###### ERR_RETURN(strm, Z_STREAM_ERROR); 540 } 541 287 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); 542 543 287 s->strm = strm; /* just in case */ 544 287 old_flush = s->last_flush; 545 287 s->last_flush = flush; 546 547 /* Write the header */ 548 287 if (s->status == INIT_STATE) { 549 #ifdef GZIP 550 41 if (s->wrap == 2) { 551 ###### put_byte(s, 31); 552 ###### put_byte(s, 139); 553 ###### put_byte(s, 8); 554 ###### put_byte(s, 0); 555 ###### put_byte(s, 0); 556 ###### put_byte(s, 0); 557 ###### put_byte(s, 0); 558 ###### put_byte(s, 0); 559 put_byte(s, s->level == 9 ? 2 : 560 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? 561 ###### 4 : 0)); 562 ###### put_byte(s, 255); 563 ###### s->status = BUSY_STATE; 564 ###### strm->adler = crc32(0L, Z_NULL, 0); 565 } 566 else 567 #endif 568 { 569 41 uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; 570 41 uInt level_flags; 571 572 41 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) 573 ###### level_flags = 0; 574 41 else if (s->level < 6) 575 ###### level_flags = 1; 576 41 else if (s->level == 6) 577 37 level_flags = 2; 578 else 579 4 level_flags = 3; 580 41 header |= (level_flags << 6); 581 41 if (s->strstart != 0) header |= PRESET_DICT; 582 41 header += 31 - (header % 31); 583 584 41 s->status = BUSY_STATE; 585 41 putShortMSB(s, header); 586 587 /* Save the adler32 of the preset dictionary: */ 588 41 if (s->strstart != 0) { 589 1 putShortMSB(s, (uInt)(strm->adler >> 16)); 590 1 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 591 } 592 41 strm->adler = adler32(0L, Z_NULL, 0); 593 } 594 } 595 596 /* Flush as much pending output as possible */ 597 287 if (s->pending != 0) { 598 59 flush_pending(strm); 599 59 if (strm->avail_out == 0) { 600 /* Since avail_out is 0, deflate will be called again with 601 * more output space, but possibly with both pending and 602 * avail_in equal to zero. There won't be anything to do, 603 * but this is not an error situation so make sure we 604 * return OK instead of BUF_ERROR at next call of deflate: 605 */ 606 10 s->last_flush = -1; 607 10 return Z_OK; 608 } 609 610 /* Make sure there is something to do and avoid duplicate consecutive 611 * flushes. For repeated and useless calls with Z_FINISH, we keep 612 * returning Z_STREAM_END instead of Z_BUF_ERROR. 613 */ 614 228 } else if (strm->avail_in == 0 && flush <= old_flush && 615 flush != Z_FINISH) { 616 ###### ERR_RETURN(strm, Z_BUF_ERROR); 617 } 618 619 /* User must not provide more input after the first FINISH: */ 620 277 if (s->status == FINISH_STATE && strm->avail_in != 0) { 621 ###### ERR_RETURN(strm, Z_BUF_ERROR); 622 } 623 624 /* Start a new block or continue the current one. 625 */ 626 277 if (strm->avail_in != 0 || s->lookahead != 0 || 627 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { 628 271 block_state bstate; 629 630 271 bstate = (*(configuration_table[s->level].func))(s, flush); 631 632 271 if (bstate == finish_started || bstate == finish_done) { 633 70 s->status = FINISH_STATE; 634 } 635 271 if (bstate == need_more || bstate == finish_started) { 636 205 if (strm->avail_out == 0) { 637 9 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ 638 } 639 205 return Z_OK; 640 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call 641 * of deflate should use the same flush parameter to make sure 642 * that the flush is complete. So we don't have to output an 643 * empty block here, this will be done at next call. This also 644 * ensures that for a very small output buffer, we emit at most 645 * one empty block. 646 */ 647 } 648 66 if (bstate == block_done) { 649 2 if (flush == Z_PARTIAL_FLUSH) { 650 1 _tr_align(s); 651 } else { /* FULL_FLUSH or SYNC_FLUSH */ 652 1 _tr_stored_block(s, (char*)0, 0L, 0); 653 /* For a full flush, this empty block will be recognized 654 * as a special marker by inflate_sync(). 655 */ 656 1 if (flush == Z_FULL_FLUSH) { 657 1 CLEAR_HASH(s); /* forget history */ 658 } 659 } 660 2 flush_pending(strm); 661 2 if (strm->avail_out == 0) { 662 ###### s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ 663 ###### return Z_OK; 664 } 665 } 666 } 667 Assert(strm->avail_out > 0, "bug2"); 668 669 72 if (flush != Z_FINISH) return Z_OK; 670 70 if (s->wrap <= 0) return Z_STREAM_END; 671 672 /* Write the trailer */ 673 #ifdef GZIP 674 41 if (s->wrap == 2) { 675 ###### put_byte(s, (Byte)(strm->adler & 0xff)); 676 ###### put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); 677 ###### put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); 678 ###### put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); 679 ###### put_byte(s, (Byte)(strm->total_in & 0xff)); 680 ###### put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); 681 ###### put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); 682 ###### put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); 683 } 684 else 685 #endif 686 { 687 41 putShortMSB(s, (uInt)(strm->adler >> 16)); 688 41 putShortMSB(s, (uInt)(strm->adler & 0xffff)); 689 } 690 41 flush_pending(strm); 691 /* If avail_out is zero, the application will call deflate again 692 * to flush the rest. 693 */ 694 41 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ 695 41 return s->pending != 0 ? Z_OK : Z_STREAM_END; 696 } 697 698 /* ========================================================================= */ 699 int ZEXPORT deflateEnd (strm) 700 z_streamp strm; 701 70 { 702 70 int status; 703 704 70 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; 705 706 70 status = strm->state->status; 707 70 if (status != INIT_STATE && status != BUSY_STATE && 708 status != FINISH_STATE) { 709 ###### return Z_STREAM_ERROR; 710 } 711 712 /* Deallocate in reverse order of allocations: */ 713 70 TRY_FREE(strm, strm->state->pending_buf); 714 70 TRY_FREE(strm, strm->state->head); 715 70 TRY_FREE(strm, strm->state->prev); 716 70 TRY_FREE(strm, strm->state->window); 717 718 70 ZFREE(strm, strm->state); 719 70 strm->state = Z_NULL; 720 721 70 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; 722 } 723 724 /* ========================================================================= 725 * Copy the source state to the destination state. 726 * To simplify the source, this is not supported for 16-bit MSDOS (which 727 * doesn't have enough memory anyway to duplicate compression states). 728 */ 729 int ZEXPORT deflateCopy (dest, source) 730 z_streamp dest; 731 z_streamp source; 732 ###### { 733 #ifdef MAXSEG_64K 734 return Z_STREAM_ERROR; 735 #else 736 ###### deflate_state *ds; 737 ###### deflate_state *ss; 738 ###### ushf *overlay; 739 740 741 ###### if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { 742 ###### return Z_STREAM_ERROR; 743 } 744 745 ###### ss = source->state; 746 747 ###### *dest = *source; 748 749 ###### ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); 750 ###### if (ds == Z_NULL) return Z_MEM_ERROR; 751 ###### dest->state = (struct internal_state FAR *) ds; 752 ###### *ds = *ss; 753 ###### ds->strm = dest; 754 755 ###### ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); 756 ###### ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); 757 ###### ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); 758 ###### overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); 759 ###### ds->pending_buf = (uchf *) overlay; 760 761 ###### if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || 762 ds->pending_buf == Z_NULL) { 763 ###### deflateEnd (dest); 764 ###### return Z_MEM_ERROR; 765 } 766 /* following zmemcpy do not work for 16-bit MSDOS */ 767 ###### zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); 768 ###### zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); 769 ###### zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); 770 ###### zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); 771 772 ###### ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); 773 ###### ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); 774 ###### ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; 775 776 ###### ds->l_desc.dyn_tree = ds->dyn_ltree; 777 ###### ds->d_desc.dyn_tree = ds->dyn_dtree; 778 ###### ds->bl_desc.dyn_tree = ds->bl_tree; 779 780 ###### return Z_OK; 781 #endif /* MAXSEG_64K */ 782 } 783 784 /* =========================================================================== 785 * Read a new buffer from the current input stream, update the adler32 786 * and total number of bytes read. All deflate() input goes through 787 * this function so some applications may wish to modify it to avoid 788 * allocating a large strm->next_in buffer and copying from it. 789 * (See also flush_pending()). 790 */ 791 local int read_buf(strm, buf, size) 792 z_streamp strm; 793 Bytef *buf; 794 unsigned size; 795 201 { 796 201 unsigned len = strm->avail_in; 797 798 201 if (len > size) len = size; 799 201 if (len == 0) return 0; 800 801 201 strm->avail_in -= len; 802 803 201 if (strm->state->wrap == 1) { 804 95 strm->adler = adler32(strm->adler, strm->next_in, len); 805 } 806 #ifdef GZIP 807 106 else if (strm->state->wrap == 2) { 808 ###### strm->adler = crc32(strm->adler, strm->next_in, len); 809 } 810 #endif 811 201 zmemcpy(buf, strm->next_in, len); 812 201 strm->next_in += len; 813 201 strm->total_in += len; 814 815 201 return (int)len; 816 } 817 818 /* =========================================================================== 819 * Initialize the "longest match" routines for a new zlib stream 820 */ 821 local void lm_init (s) 822 deflate_state *s; 823 70 { 824 70 s->window_size = (ulg)2L*s->w_size; 825 826 70 CLEAR_HASH(s); 827 828 /* Set the default configuration parameters: 829 */ 830 70 s->max_lazy_match = configuration_table[s->level].max_lazy; 831 70 s->good_match = configuration_table[s->level].good_length; 832 70 s->nice_match = configuration_table[s->level].nice_length; 833 70 s->max_chain_length = configuration_table[s->level].max_chain; 834 835 70 s->strstart = 0; 836 70 s->block_start = 0L; 837 70 s->lookahead = 0; 838 70 s->match_length = s->prev_length = MIN_MATCH-1; 839 70 s->match_available = 0; 840 70 s->ins_h = 0; 841 #ifdef ASMV 842 match_init(); /* initialize the asm code */ 843 #endif 844 } 845 846 #ifndef FASTEST 847 /* =========================================================================== 848 * Set match_start to the longest match starting at the given string and 849 * return its length. Matches shorter or equal to prev_length are discarded, 850 * in which case the result is equal to prev_length and match_start is 851 * garbage. 852 * IN assertions: cur_match is the head of the hash chain for the current 853 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 854 * OUT assertion: the match length is not greater than s->lookahead. 855 */ 856 #ifndef ASMV 857 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or 858 * match.S. The code will be functionally equivalent. 859 */ 860 local uInt longest_match(s, cur_match) 861 deflate_state *s; 862 IPos cur_match; /* current match */ 863 11706 { 864 11706 unsigned chain_length = s->max_chain_length;/* max hash chain length */ 865 11706 register Bytef *scan = s->window + s->strstart; /* current string */ 866 11706 register Bytef *match; /* matched string */ 867 11706 register int len; /* length of current match */ 868 11706 int best_len = s->prev_length; /* best match length so far */ 869 11706 int nice_match = s->nice_match; /* stop if match long enough */ 870 11706 IPos limit = s->strstart > (IPos)MAX_DIST(s) ? 871 11706 s->strstart - (IPos)MAX_DIST(s) : NIL; 872 /* Stop when cur_match becomes <= limit. To simplify the code, 873 * we prevent matches with the string of window index 0. 874 */ 875 11706 Posf *prev = s->prev; 876 11706 uInt wmask = s->w_mask; 877 878 #ifdef UNALIGNED_OK 879 /* Compare two bytes at a time. Note: this is not always beneficial. 880 * Try with and without -DUNALIGNED_OK to check. 881 */ 882 register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; 883 register ush scan_start = *(ushf*)scan; 884 register ush scan_end = *(ushf*)(scan+best_len-1); 885 #else 886 11706 register Bytef *strend = s->window + s->strstart + MAX_MATCH; 887 11706 register Byte scan_end1 = scan[best_len-1]; 888 11706 register Byte scan_end = scan[best_len]; 889 #endif 890 891 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 892 * It is easy to get rid of this optimization if necessary. 893 */ 894 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); 895 896 /* Do not waste too much time if we already have a good match: */ 897 11706 if (s->prev_length >= s->good_match) { 898 10 chain_length >>= 2; 899 } 900 /* Do not look for matches beyond the end of the input. This is necessary 901 * to make deflate deterministic. 902 */ 903 11706 if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; 904 905 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); 906 907 27393 do { 908 Assert(cur_match < s->strstart, "no future"); 909 27393 match = s->window + cur_match; 910 911 /* Skip to next match if the match length cannot increase 912 * or if the match length is less than 2: 913 */ 914 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258) 915 /* This code assumes sizeof(unsigned short) == 2. Do not use 916 * UNALIGNED_OK if your compiler uses a different size. 917 */ 918 if (*(ushf*)(match+best_len-1) != scan_end || 919 *(ushf*)match != scan_start) continue; 920 921 /* It is not necessary to compare scan[2] and match[2] since they are 922 * always equal when the other bytes match, given that the hash keys 923 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at 924 * strstart+3, +5, ... up to strstart+257. We check for insufficient 925 * lookahead only every 4th comparison; the 128th check will be made 926 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is 927 * necessary to put more guard bytes at the end of the window, or 928 * to check more often for insufficient lookahead. 929 */ 930 Assert(scan[2] == match[2], "scan[2]?"); 931 scan++, match++; 932 do { 933 } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && 934 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 935 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 936 *(ushf*)(scan+=2) == *(ushf*)(match+=2) && 937 scan < strend); 938 /* The funny "do {}" generates better code on most compilers */ 939 940 /* Here, scan <= window+strstart+257 */ 941 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 942 if (*scan == *match) scan++; 943 944 len = (MAX_MATCH - 1) - (int)(strend-scan); 945 scan = strend - (MAX_MATCH-1); 946 947 #else /* UNALIGNED_OK */ 948 949 27393 if (match[best_len] != scan_end || 950 match[best_len-1] != scan_end1 || 951 *match != *scan || 952 11927 *++match != scan[1]) continue; 953 954 /* The check at best_len-1 can be removed because it will be made 955 * again later. (This heuristic is not always a win.) 956 * It is not necessary to compare scan[2] and match[2] since they 957 * are always equal when the other bytes match, given that 958 * the hash keys are equal and that HASH_BITS >= 8. 959 */ 960 11927 scan += 2, match++; 961 Assert(*scan == *match, "match[2]?"); 962 963 /* We check for insufficient lookahead only every 8th comparison; 964 * the 256th check will be made at strstart+258. 965 */ 966 42810 do { 967 } while (*++scan == *++match && *++scan == *++match && 968 *++scan == *++match && *++scan == *++match && 969 *++scan == *++match && *++scan == *++match && 970 *++scan == *++match && *++scan == *++match && 971 scan < strend); 972 973 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 974 975 11927 len = MAX_MATCH - (int)(strend - scan); 976 11927 scan = strend - MAX_MATCH; 977 978 #endif /* UNALIGNED_OK */ 979 980 11927 if (len > best_len) { 981 11920 s->match_start = cur_match; 982 11920 best_len = len; 983 11920 if (len >= nice_match) break; 984 #ifdef UNALIGNED_OK 985 scan_end = *(ushf*)(scan+best_len-1); 986 #else 987 7926 scan_end1 = scan[best_len-1]; 988 7926 scan_end = scan[best_len]; 989 #endif 990 } 991 23399 } while ((cur_match = prev[cur_match & wmask]) > limit 992 && --chain_length != 0); 993 994 11706 if ((uInt)best_len <= s->lookahead) return (uInt)best_len; 995 9 return s->lookahead; 996 } 997 #endif /* ASMV */ 998 #endif /* FASTEST */ 999 1000 /* --------------------------------------------------------------------------- 1001 * Optimized version for level == 1 or strategy == Z_RLE only 1002 */ 1003 local uInt longest_match_fast(s, cur_match) 1004 deflate_state *s; 1005 IPos cur_match; /* current match */ 1006 ###### { 1007 ###### register Bytef *scan = s->window + s->strstart; /* current string */ 1008 ###### register Bytef *match; /* matched string */ 1009 ###### register int len; /* length of current match */ 1010 ###### register Bytef *strend = s->window + s->strstart + MAX_MATCH; 1011 1012 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. 1013 * It is easy to get rid of this optimization if necessary. 1014 */ 1015 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); 1016 1017 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); 1018 1019 Assert(cur_match < s->strstart, "no future"); 1020 1021 ###### match = s->window + cur_match; 1022 1023 /* Return failure if the match length is less than 2: 1024 */ 1025 ###### if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; 1026 1027 /* The check at best_len-1 can be removed because it will be made 1028 * again later. (This heuristic is not always a win.) 1029 * It is not necessary to compare scan[2] and match[2] since they 1030 * are always equal when the other bytes match, given that 1031 * the hash keys are equal and that HASH_BITS >= 8. 1032 */ 1033 ###### scan += 2, match += 2; 1034 Assert(*scan == *match, "match[2]?"); 1035 1036 /* We check for insufficient lookahead only every 8th comparison; 1037 * the 256th check will be made at strstart+258. 1038 */ 1039 ###### do { 1040 } while (*++scan == *++match && *++scan == *++match && 1041 *++scan == *++match && *++scan == *++match && 1042 *++scan == *++match && *++scan == *++match && 1043 *++scan == *++match && *++scan == *++match && 1044 scan < strend); 1045 1046 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); 1047 1048 ###### len = MAX_MATCH - (int)(strend - scan); 1049 1050 ###### if (len < MIN_MATCH) return MIN_MATCH - 1; 1051 1052 ###### s->match_start = cur_match; 1053 ###### return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; 1054 } 1055 1056 #ifdef DEBUG 1057 /* =========================================================================== 1058 * Check that the match at match_start is indeed a match. 1059 */ 1060 local void check_match(s, start, match, length) 1061 deflate_state *s; 1062 IPos start, match; 1063 int length; 1064 { 1065 /* check that the match is indeed a match */ 1066 if (zmemcmp(s->window + match, 1067 s->window + start, length) != EQUAL) { 1068 fprintf(stderr, " start %u, match %u, length %d\n", 1069 start, match, length); 1070 do { 1071 fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); 1072 } while (--length != 0); 1073 z_error("invalid match"); 1074 } 1075 if (z_verbose > 1) { 1076 fprintf(stderr,"\\[%d,%d]", start-match, length); 1077 do { putc(s->window[start++], stderr); } while (--length != 0); 1078 } 1079 } 1080 #else 1081 # define check_match(s, start, match, length) 1082 #endif /* DEBUG */ 1083 1084 /* =========================================================================== 1085 * Fill the window when the lookahead becomes insufficient. 1086 * Updates strstart and lookahead. 1087 * 1088 * IN assertion: lookahead < MIN_LOOKAHEAD 1089 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD 1090 * At least one byte has been read, or avail_in == 0; reads are 1091 * performed for at least two bytes (required for the zip translate_eol 1092 * option -- not supported here). 1093 */ 1094 local void fill_window(s) 1095 deflate_state *s; 1096 2891 { 1097 2891 register unsigned n, m; 1098 2891 register Posf *p; 1099 2891 unsigned more; /* Amount of free space at the end of the window. */ 1100 2891 uInt wsize = s->w_size; 1101 1102 2891 do { 1103 2891 more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); 1104 1105 /* Deal with !@#$% 64K limit: */ 1106 2891 if (sizeof(int) <= 2) { 1107 2891 if (more == 0 && s->strstart == 0 && s->lookahead == 0) { 1108 2891 more = wsize; 1109 1110 2891 } else if (more == (unsigned)(-1)) { 1111 /* Very unlikely, but possible on 16 bit machine if 1112 * strstart == 0 && lookahead == 1 (input done a byte at time) 1113 */ 1114 2891 more--; 1115 } 1116 } 1117 1118 /* If the window is almost full and there is insufficient lookahead, 1119 * move the upper half to the lower one to make room in the upper half. 1120 */ 1121 2891 if (s->strstart >= wsize+MAX_DIST(s)) { 1122 1123 4 zmemcpy(s->window, s->window+wsize, (unsigned)wsize); 1124 4 s->match_start -= wsize; 1125 4 s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ 1126 4 s->block_start -= (long) wsize; 1127 1128 /* Slide the hash table (could be avoided with 32 bit values 1129 at the expense of memory usage). We slide even when level == 0 1130 to keep the hash table consistent if we switch back to level > 0 1131 later. (Using level 0 permanently is not an optimal usage of 1132 zlib, so we don't care about this pathological case.) 1133 */ 1134 4 n = s->hash_size; 1135 4 p = &s->head[n]; 1136 229376 do { 1137 229376 m = *--p; 1138 229376 *p = (Pos)(m >= wsize ? m-wsize : NIL); 1139 229376 } while (--n); 1140 1141 4 n = wsize; 1142 #ifndef FASTEST 1143 4 p = &s->prev[n]; 1144 131072 do { 1145 131072 m = *--p; 1146 131072 *p = (Pos)(m >= wsize ? m-wsize : NIL); 1147 /* If n is not on any hash chain, prev[n] is garbage but 1148 * its value will never be used. 1149 */ 1150 131072 } while (--n); 1151 #endif 1152 4 more += wsize; 1153 } 1154 2891 if (s->strm->avail_in == 0) return; 1155 1156 /* If there was no sliding: 1157 * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && 1158 * more == window_size - lookahead - strstart 1159 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) 1160 * => more >= window_size - 2*WSIZE + 2 1161 * In the BIG_MEM or MMAP case (not yet supported), 1162 * window_size == input_size + MIN_LOOKAHEAD && 1163 * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. 1164 * Otherwise, window_size == 2*WSIZE so more >= 2. 1165 * If there was sliding, more >= WSIZE. So in all cases, more >= 2. 1166 */ 1167 Assert(more >= 2, "more < 2"); 1168 1169 201 n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); 1170 201 s->lookahead += n; 1171 1172 /* Initialize the hash value now that we have some input: */ 1173 201 if (s->lookahead >= MIN_MATCH) { 1174 185 s->ins_h = s->window[s->strstart]; 1175 185 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 1176 #if MIN_MATCH != 3 1177 Call UPDATE_HASH() MIN_MATCH-3 more times 1178 #endif 1179 } 1180 /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, 1181 * but this is not important since only literal bytes will be emitted. 1182 */ 1183 1184 201 } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); 1185 } 1186 1187 /* =========================================================================== 1188 * Flush the current block, with given end-of-file flag. 1189 * IN assertion: strstart is set to the end of the current match. 1190 */ 1191 #define FLUSH_BLOCK_ONLY(s, eof) { \ 1192 _tr_flush_block(s, (s->block_start >= 0L ? \ 1193 (charf *)&s->window[(unsigned)s->block_start] : \ 1194 (charf *)Z_NULL), \ 1195 (ulg)((long)s->strstart - s->block_start), \ 1196 (eof)); \ 1197 s->block_start = s->strstart; \ 1198 flush_pending(s->strm); \ 1199 Tracev((stderr,"[FLUSH]")); \ 1200 } 1201 1202 /* Same but force premature exit if necessary. */ 1203 #define FLUSH_BLOCK(s, eof) { \ 1204 FLUSH_BLOCK_ONLY(s, eof); \ 1205 if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \ 1206 } 1207 1208 /* =========================================================================== 1209 * Copy without compression as much as possible from the input stream, return 1210 * the current block state. 1211 * This function does not insert new strings in the dictionary since 1212 * uncompressible data is probably not useful. This function is used 1213 * only for the level=0 compression option. 1214 * NOTE: this function should be optimized to avoid extra copying from 1215 * window to pending_buf. 1216 */ 1217 local block_state deflate_stored(s, flush) 1218 deflate_state *s; 1219 int flush; 1220 3 { 1221 /* Stored blocks are limited to 0xffff bytes, pending_buf is limited 1222 * to pending_buf_size, and each stored block has a 5 byte header: 1223 */ 1224 3 ulg max_block_size = 0xffff; 1225 3 ulg max_start; 1226 1227 3 if (max_block_size > s->pending_buf_size - 5) { 1228 ###### max_block_size = s->pending_buf_size - 5; 1229 } 1230 1231 /* Copy as much as possible from input to output: */ 1232 6 for (;;) { 1233 /* Fill the window as much as possible: */ 1234 5 if (s->lookahead <= 1) { 1235 1236 Assert(s->strstart < s->w_size+MAX_DIST(s) || 1237 s->block_start >= (long)s->w_size, "slide too late"); 1238 1239 5 fill_window(s); 1240 5 if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; 1241 1242 4 if (s->lookahead == 0) break; /* flush the current block */ 1243 } 1244 Assert(s->block_start >= 0L, "block gone"); 1245 1246 3 s->strstart += s->lookahead; 1247 3 s->lookahead = 0; 1248 1249 /* Emit a stored block if pending_buf will be full: */ 1250 3 max_start = s->block_start + max_block_size; 1251 3 if (s->strstart == 0 || (ulg)s->strstart >= max_start) { 1252 /* strstart == 0 is possible when wraparound on 16-bit machine */ 1253 ###### s->lookahead = (uInt)(s->strstart - max_start); 1254 ###### s->strstart = (uInt)max_start; 1255 ###### FLUSH_BLOCK(s, 0); 1256 } 1257 /* Flush if we may have to slide, otherwise block_start may become 1258 * negative and the data will be gone: 1259 */ 1260 3 if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { 1261 1 FLUSH_BLOCK(s, 0); 1262 } 1263 } 1264 1 FLUSH_BLOCK(s, flush == Z_FINISH); 1265 1 return flush == Z_FINISH ? finish_done : block_done; 1266 } 1267 1268 /* =========================================================================== 1269 * Compress as much as possible from the input stream, return the current 1270 * block state. 1271 * This function does not perform lazy evaluation of matches and inserts 1272 * new strings in the dictionary only for unmatched strings or for short 1273 * matches. It is used only for the fast compression options. 1274 */ 1275 local block_state deflate_fast(s, flush) 1276 deflate_state *s; 1277 int flush; 1278 61 { 1279 61 IPos hash_head = NIL; /* head of the hash chain */ 1280 67070 int bflush; /* set if current block must be flushed */ 1281 1282 67078 for (;;) { 1283 /* Make sure that we always have enough lookahead, except 1284 * at the end of the input file. We need MAX_MATCH bytes 1285 * for the next match, plus MIN_MATCH bytes to insert the 1286 * string following the next match. 1287 */ 1288 67070 if (s->lookahead < MIN_LOOKAHEAD) { 1289 639 fill_window(s); 1290 639 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 1291 53 return need_more; 1292 } 1293 586 if (s->lookahead == 0) break; /* flush the current block */ 1294 } 1295 1296 /* Insert the string window[strstart .. strstart+2] in the 1297 * dictionary, and set hash_head to the head of the hash chain: 1298 */ 1299 67009 if (s->lookahead >= MIN_MATCH) { 1300 67005 INSERT_STRING(s, s->strstart, hash_head); 1301 } 1302 1303 /* Find the longest match, discarding those <= prev_length. 1304 * At this point we have always match_length < MIN_MATCH 1305 */ 1306 67009 if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { 1307 /* To simplify the code, we prevent matches with the string 1308 * of window index 0 (in particular we have to avoid a match 1309 * of the string with itself at the start of the input file). 1310 */ 1311 #ifdef FASTEST 1312 if ((s->strategy < Z_HUFFMAN_ONLY) || 1313 (s->strategy == Z_RLE && s->strstart - hash_head == 1)) { 1314 s->match_length = longest_match_fast (s, hash_head); 1315 } 1316 #else 1317 61796 if (s->strategy < Z_HUFFMAN_ONLY) { 1318 9562 s->match_length = longest_match (s, hash_head); 1319 52234 } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { 1320 ###### s->match_length = longest_match_fast (s, hash_head); 1321 } 1322 #endif 1323 /* longest_match() or longest_match_fast() sets match_start */ 1324 } 1325 67009 if (s->match_length >= MIN_MATCH) { 1326 check_match(s, s->strstart, s->match_start, s->match_length); 1327 1328 _tr_tally_dist(s, s->strstart - s->match_start, 1329 8980 s->match_length - MIN_MATCH, bflush); 1330 1331 8980 s->lookahead -= s->match_length; 1332 1333 /* Insert new strings in the hash table only if the match length 1334 * is not too large. This saves time but degrades compression. 1335 */ 1336 #ifndef FASTEST 1337 8980 if (s->match_length <= s->max_insert_length && 1338 s->lookahead >= MIN_MATCH) { 1339 3627 s->match_length--; /* string at strstart already in table */ 1340 9112 do { 1341 9112 s->strstart++; 1342 9112 INSERT_STRING(s, s->strstart, hash_head); 1343 /* strstart never exceeds WSIZE-MAX_MATCH, so there are 1344 * always MIN_MATCH bytes ahead. 1345 */ 1346 9112 } while (--s->match_length != 0); 1347 3627 s->strstart++; 1348 } else 1349 #endif 1350 { 1351 5353 s->strstart += s->match_length; 1352 5353 s->match_length = 0; 1353 5353 s->ins_h = s->window[s->strstart]; 1354 5353 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); 1355 #if MIN_MATCH != 3 1356 Call UPDATE_HASH() MIN_MATCH-3 more times 1357 #endif 1358 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not 1359 * matter since it will be recomputed at next deflate call. 1360 */ 1361 } 1362 } else { 1363 /* No match, output a literal byte */ 1364 Tracevv((stderr,"%c", s->window[s->strstart])); 1365 58029 _tr_tally_lit (s, s->window[s->strstart], bflush); 1366 58029 s->lookahead--; 1367 58029 s->strstart++; 1368 } 1369 67009 if (bflush) FLUSH_BLOCK(s, 0); 1370 } 1371 8 FLUSH_BLOCK(s, flush == Z_FINISH); 1372 7 return flush == Z_FINISH ? finish_done : block_done; 1373 } 1374 1375 #ifndef FASTEST 1376 /* =========================================================================== 1377 * Same as above, but achieves better compression. We use a lazy 1378 * evaluation for matches: a match is finally adopted only if there is 1379 * no better match at the next window position. 1380 */ 1381 local block_state deflate_slow(s, flush) 1382 deflate_state *s; 1383 int flush; 1384 207 { 1385 207 IPos hash_head = NIL; /* head of hash chain */ 1386 27654 int bflush; /* set if current block must be flushed */ 1387 1388 /* Process the input block. */ 1389 28559 for (;;) { 1390 /* Make sure that we always have enough lookahead, except 1391 * at the end of the input file. We need MAX_MATCH bytes 1392 * for the next match, plus MIN_MATCH bytes to insert the 1393 * string following the next match. 1394 */ 1395 27654 if (s->lookahead < MIN_LOOKAHEAD) { 1396 2247 fill_window(s); 1397 2247 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { 1398 142 return need_more; 1399 } 1400 2105 if (s->lookahead == 0) break; /* flush the current block */ 1401 } 1402 1403 /* Insert the string window[strstart .. strstart+2] in the 1404 * dictionary, and set hash_head to the head of the hash chain: 1405 */ 1406 27447 if (s->lookahead >= MIN_MATCH) { 1407 27353 INSERT_STRING(s, s->strstart, hash_head); 1408 } 1409 1410 /* Find the longest match, discarding those <= prev_length. 1411 */ 1412 27447 s->prev_length = s->match_length, s->prev_match = s->match_start; 1413 27447 s->match_length = MIN_MATCH-1; 1414 1415 27447 if (hash_head != NIL && s->prev_length < s->max_lazy_match && 1416 s->strstart - hash_head <= MAX_DIST(s)) { 1417 /* To simplify the code, we prevent matches with the string 1418 * of window index 0 (in particular we have to avoid a match 1419 * of the string with itself at the start of the input file). 1420 */ 1421 2144 if (s->strategy < Z_HUFFMAN_ONLY) { 1422 2144 s->match_length = longest_match (s, hash_head); 1423 ###### } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) { 1424 ###### s->match_length = longest_match_fast (s, hash_head); 1425 } 1426 /* longest_match() or longest_match_fast() sets match_start */ 1427 1428 2144 if (s->match_length <= 5 && (s->strategy == Z_FILTERED 1429 #if TOO_FAR <= 32767 1430 || (s->match_length == MIN_MATCH && 1431 s->strstart - s->match_start > TOO_FAR) 1432 #endif 1433 )) { 1434 1435 /* If prev_match is also MIN_MATCH, match_start is garbage 1436 * but we will ignore the current match anyway. 1437 */ 1438 ###### s->match_length = MIN_MATCH-1; 1439 } 1440 } 1441 /* If there was a match at the previous step and the current 1442 * match is not better, output the previous match: 1443 */ 1444 27447 if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { 1445 854 uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; 1446 /* Do not insert strings in hash table beyond this. */ 1447 1448 check_match(s, s->strstart-1, s->prev_match, s->prev_length); 1449 1450 _tr_tally_dist(s, s->strstart -1 - s->prev_match, 1451 854 s->prev_length - MIN_MATCH, bflush); 1452 1453 /* Insert in hash table all strings up to the end of the match. 1454 * strstart-1 and strstart are already inserted. If there is not 1455 * enough lookahead, the last two strings are not inserted in 1456 * the hash table. 1457 */ 1458 854 s->lookahead -= s->prev_length-1; 1459 854 s->prev_length -= 2; 1460 203847 do { 1461 203847 if (++s->strstart <= max_insert) { 1462 203827 INSERT_STRING(s, s->strstart, hash_head); 1463 } 1464 203847 } while (--s->prev_length != 0); 1465 854 s->match_available = 0; 1466 854 s->match_length = MIN_MATCH-1; 1467 854 s->strstart++; 1468 1469 854 if (bflush) FLUSH_BLOCK(s, 0); 1470 1471 26593 } else if (s->match_available) { 1472 /* If there was no match at the previous position, output a 1473 * single literal. If there was a match but the current match 1474 * is longer, truncate the previous match to a single literal. 1475 */ 1476 Tracevv((stderr,"%c", s->window[s->strstart-1])); 1477 25688 _tr_tally_lit(s, s->window[s->strstart-1], bflush); 1478 25688 if (bflush) { 1479 ###### FLUSH_BLOCK_ONLY(s, 0); 1480 } 1481 25688 s->strstart++; 1482 25688 s->lookahead--; 1483 25688 if (s->strm->avail_out == 0) return need_more; 1484 } else { 1485 /* There is no previous match to compare with, wait for 1486 * the next step to decide. 1487 */ 1488 905 s->match_available = 1; 1489 905 s->strstart++; 1490 905 s->lookahead--; 1491 } 1492 } 1493 Assert (flush != Z_NO_FLUSH, "no flush?"); 1494 65 if (s->match_available) { 1495 Tracevv((stderr,"%c", s->window[s->strstart-1])); 1496 51 _tr_tally_lit(s, s->window[s->strstart-1], bflush); 1497 51 s->match_available = 0; 1498 } 1499 65 FLUSH_BLOCK(s, flush == Z_FINISH); 1500 58 return flush == Z_FINISH ? finish_done : block_done; 1501 } 1502 #endif /* FASTEST */