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annotate libs/zlib/deflate.c @ 43:73813c1176de

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author John Tsiombikas <nuclear@member.fsf.org>
date Fri, 14 Aug 2015 04:33:42 +0300
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nuclear@26 1 /* deflate.c -- compress data using the deflation algorithm
nuclear@26 2 * Copyright (C) 1995-2005 Jean-loup Gailly.
nuclear@26 3 * For conditions of distribution and use, see copyright notice in zlib.h
nuclear@26 4 */
nuclear@26 5
nuclear@26 6 /*
nuclear@26 7 * ALGORITHM
nuclear@26 8 *
nuclear@26 9 * The "deflation" process depends on being able to identify portions
nuclear@26 10 * of the input text which are identical to earlier input (within a
nuclear@26 11 * sliding window trailing behind the input currently being processed).
nuclear@26 12 *
nuclear@26 13 * The most straightforward technique turns out to be the fastest for
nuclear@26 14 * most input files: try all possible matches and select the longest.
nuclear@26 15 * The key feature of this algorithm is that insertions into the string
nuclear@26 16 * dictionary are very simple and thus fast, and deletions are avoided
nuclear@26 17 * completely. Insertions are performed at each input character, whereas
nuclear@26 18 * string matches are performed only when the previous match ends. So it
nuclear@26 19 * is preferable to spend more time in matches to allow very fast string
nuclear@26 20 * insertions and avoid deletions. The matching algorithm for small
nuclear@26 21 * strings is inspired from that of Rabin & Karp. A brute force approach
nuclear@26 22 * is used to find longer strings when a small match has been found.
nuclear@26 23 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
nuclear@26 24 * (by Leonid Broukhis).
nuclear@26 25 * A previous version of this file used a more sophisticated algorithm
nuclear@26 26 * (by Fiala and Greene) which is guaranteed to run in linear amortized
nuclear@26 27 * time, but has a larger average cost, uses more memory and is patented.
nuclear@26 28 * However the F&G algorithm may be faster for some highly redundant
nuclear@26 29 * files if the parameter max_chain_length (described below) is too large.
nuclear@26 30 *
nuclear@26 31 * ACKNOWLEDGEMENTS
nuclear@26 32 *
nuclear@26 33 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
nuclear@26 34 * I found it in 'freeze' written by Leonid Broukhis.
nuclear@26 35 * Thanks to many people for bug reports and testing.
nuclear@26 36 *
nuclear@26 37 * REFERENCES
nuclear@26 38 *
nuclear@26 39 * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
nuclear@26 40 * Available in http://www.ietf.org/rfc/rfc1951.txt
nuclear@26 41 *
nuclear@26 42 * A description of the Rabin and Karp algorithm is given in the book
nuclear@26 43 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
nuclear@26 44 *
nuclear@26 45 * Fiala,E.R., and Greene,D.H.
nuclear@26 46 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
nuclear@26 47 *
nuclear@26 48 */
nuclear@26 49
nuclear@26 50 /* @(#) $Id$ */
nuclear@26 51
nuclear@26 52 #include "deflate.h"
nuclear@26 53
nuclear@26 54 const char deflate_copyright[] =
nuclear@26 55 " deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly ";
nuclear@26 56 /*
nuclear@26 57 If you use the zlib library in a product, an acknowledgment is welcome
nuclear@26 58 in the documentation of your product. If for some reason you cannot
nuclear@26 59 include such an acknowledgment, I would appreciate that you keep this
nuclear@26 60 copyright string in the executable of your product.
nuclear@26 61 */
nuclear@26 62
nuclear@26 63 /* ===========================================================================
nuclear@26 64 * Function prototypes.
nuclear@26 65 */
nuclear@26 66 typedef enum {
nuclear@26 67 need_more, /* block not completed, need more input or more output */
nuclear@26 68 block_done, /* block flush performed */
nuclear@26 69 finish_started, /* finish started, need only more output at next deflate */
nuclear@26 70 finish_done /* finish done, accept no more input or output */
nuclear@26 71 } block_state;
nuclear@26 72
nuclear@26 73 typedef block_state (*compress_func) OF((deflate_state *s, int flush));
nuclear@26 74 /* Compression function. Returns the block state after the call. */
nuclear@26 75
nuclear@26 76 local void fill_window OF((deflate_state *s));
nuclear@26 77 local block_state deflate_stored OF((deflate_state *s, int flush));
nuclear@26 78 local block_state deflate_fast OF((deflate_state *s, int flush));
nuclear@26 79 #ifndef FASTEST
nuclear@26 80 local block_state deflate_slow OF((deflate_state *s, int flush));
nuclear@26 81 #endif
nuclear@26 82 local void lm_init OF((deflate_state *s));
nuclear@26 83 local void putShortMSB OF((deflate_state *s, uInt b));
nuclear@26 84 local void flush_pending OF((z_streamp strm));
nuclear@26 85 local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
nuclear@26 86 #ifndef FASTEST
nuclear@26 87 #ifdef ASMV
nuclear@26 88 void match_init OF((void)); /* asm code initialization */
nuclear@26 89 uInt longest_match OF((deflate_state *s, IPos cur_match));
nuclear@26 90 #else
nuclear@26 91 local uInt longest_match OF((deflate_state *s, IPos cur_match));
nuclear@26 92 #endif
nuclear@26 93 #endif
nuclear@26 94 local uInt longest_match_fast OF((deflate_state *s, IPos cur_match));
nuclear@26 95
nuclear@26 96 #ifdef DEBUG
nuclear@26 97 local void check_match OF((deflate_state *s, IPos start, IPos match,
nuclear@26 98 int length));
nuclear@26 99 #endif
nuclear@26 100
nuclear@26 101 /* ===========================================================================
nuclear@26 102 * Local data
nuclear@26 103 */
nuclear@26 104
nuclear@26 105 #define NIL 0
nuclear@26 106 /* Tail of hash chains */
nuclear@26 107
nuclear@26 108 #ifndef TOO_FAR
nuclear@26 109 # define TOO_FAR 4096
nuclear@26 110 #endif
nuclear@26 111 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
nuclear@26 112
nuclear@26 113 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
nuclear@26 114 /* Minimum amount of lookahead, except at the end of the input file.
nuclear@26 115 * See deflate.c for comments about the MIN_MATCH+1.
nuclear@26 116 */
nuclear@26 117
nuclear@26 118 /* Values for max_lazy_match, good_match and max_chain_length, depending on
nuclear@26 119 * the desired pack level (0..9). The values given below have been tuned to
nuclear@26 120 * exclude worst case performance for pathological files. Better values may be
nuclear@26 121 * found for specific files.
nuclear@26 122 */
nuclear@26 123 typedef struct config_s {
nuclear@26 124 ush good_length; /* reduce lazy search above this match length */
nuclear@26 125 ush max_lazy; /* do not perform lazy search above this match length */
nuclear@26 126 ush nice_length; /* quit search above this match length */
nuclear@26 127 ush max_chain;
nuclear@26 128 compress_func func;
nuclear@26 129 } config;
nuclear@26 130
nuclear@26 131 #ifdef FASTEST
nuclear@26 132 local const config configuration_table[2] = {
nuclear@26 133 /* good lazy nice chain */
nuclear@26 134 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
nuclear@26 135 /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
nuclear@26 136 #else
nuclear@26 137 local const config configuration_table[10] = {
nuclear@26 138 /* good lazy nice chain */
nuclear@26 139 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
nuclear@26 140 /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
nuclear@26 141 /* 2 */ {4, 5, 16, 8, deflate_fast},
nuclear@26 142 /* 3 */ {4, 6, 32, 32, deflate_fast},
nuclear@26 143
nuclear@26 144 /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
nuclear@26 145 /* 5 */ {8, 16, 32, 32, deflate_slow},
nuclear@26 146 /* 6 */ {8, 16, 128, 128, deflate_slow},
nuclear@26 147 /* 7 */ {8, 32, 128, 256, deflate_slow},
nuclear@26 148 /* 8 */ {32, 128, 258, 1024, deflate_slow},
nuclear@26 149 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
nuclear@26 150 #endif
nuclear@26 151
nuclear@26 152 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
nuclear@26 153 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
nuclear@26 154 * meaning.
nuclear@26 155 */
nuclear@26 156
nuclear@26 157 #define EQUAL 0
nuclear@26 158 /* result of memcmp for equal strings */
nuclear@26 159
nuclear@26 160 #ifndef NO_DUMMY_DECL
nuclear@26 161 struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
nuclear@26 162 #endif
nuclear@26 163
nuclear@26 164 /* ===========================================================================
nuclear@26 165 * Update a hash value with the given input byte
nuclear@26 166 * IN assertion: all calls to to UPDATE_HASH are made with consecutive
nuclear@26 167 * input characters, so that a running hash key can be computed from the
nuclear@26 168 * previous key instead of complete recalculation each time.
nuclear@26 169 */
nuclear@26 170 #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
nuclear@26 171
nuclear@26 172
nuclear@26 173 /* ===========================================================================
nuclear@26 174 * Insert string str in the dictionary and set match_head to the previous head
nuclear@26 175 * of the hash chain (the most recent string with same hash key). Return
nuclear@26 176 * the previous length of the hash chain.
nuclear@26 177 * If this file is compiled with -DFASTEST, the compression level is forced
nuclear@26 178 * to 1, and no hash chains are maintained.
nuclear@26 179 * IN assertion: all calls to to INSERT_STRING are made with consecutive
nuclear@26 180 * input characters and the first MIN_MATCH bytes of str are valid
nuclear@26 181 * (except for the last MIN_MATCH-1 bytes of the input file).
nuclear@26 182 */
nuclear@26 183 #ifdef FASTEST
nuclear@26 184 #define INSERT_STRING(s, str, match_head) \
nuclear@26 185 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
nuclear@26 186 match_head = s->head[s->ins_h], \
nuclear@26 187 s->head[s->ins_h] = (Pos)(str))
nuclear@26 188 #else
nuclear@26 189 #define INSERT_STRING(s, str, match_head) \
nuclear@26 190 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
nuclear@26 191 match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
nuclear@26 192 s->head[s->ins_h] = (Pos)(str))
nuclear@26 193 #endif
nuclear@26 194
nuclear@26 195 /* ===========================================================================
nuclear@26 196 * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
nuclear@26 197 * prev[] will be initialized on the fly.
nuclear@26 198 */
nuclear@26 199 #define CLEAR_HASH(s) \
nuclear@26 200 s->head[s->hash_size-1] = NIL; \
nuclear@26 201 zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
nuclear@26 202
nuclear@26 203 /* ========================================================================= */
nuclear@26 204 int ZEXPORT deflateInit_(strm, level, version, stream_size)
nuclear@26 205 z_streamp strm;
nuclear@26 206 int level;
nuclear@26 207 const char *version;
nuclear@26 208 int stream_size;
nuclear@26 209 {
nuclear@26 210 return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
nuclear@26 211 Z_DEFAULT_STRATEGY, version, stream_size);
nuclear@26 212 /* To do: ignore strm->next_in if we use it as window */
nuclear@26 213 }
nuclear@26 214
nuclear@26 215 /* ========================================================================= */
nuclear@26 216 int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
nuclear@26 217 version, stream_size)
nuclear@26 218 z_streamp strm;
nuclear@26 219 int level;
nuclear@26 220 int method;
nuclear@26 221 int windowBits;
nuclear@26 222 int memLevel;
nuclear@26 223 int strategy;
nuclear@26 224 const char *version;
nuclear@26 225 int stream_size;
nuclear@26 226 {
nuclear@26 227 deflate_state *s;
nuclear@26 228 int wrap = 1;
nuclear@26 229 static const char my_version[] = ZLIB_VERSION;
nuclear@26 230
nuclear@26 231 ushf *overlay;
nuclear@26 232 /* We overlay pending_buf and d_buf+l_buf. This works since the average
nuclear@26 233 * output size for (length,distance) codes is <= 24 bits.
nuclear@26 234 */
nuclear@26 235
nuclear@26 236 if (version == Z_NULL || version[0] != my_version[0] ||
nuclear@26 237 stream_size != sizeof(z_stream)) {
nuclear@26 238 return Z_VERSION_ERROR;
nuclear@26 239 }
nuclear@26 240 if (strm == Z_NULL) return Z_STREAM_ERROR;
nuclear@26 241
nuclear@26 242 strm->msg = Z_NULL;
nuclear@26 243 if (strm->zalloc == (alloc_func)0) {
nuclear@26 244 strm->zalloc = zcalloc;
nuclear@26 245 strm->opaque = (voidpf)0;
nuclear@26 246 }
nuclear@26 247 if (strm->zfree == (free_func)0) strm->zfree = zcfree;
nuclear@26 248
nuclear@26 249 #ifdef FASTEST
nuclear@26 250 if (level != 0) level = 1;
nuclear@26 251 #else
nuclear@26 252 if (level == Z_DEFAULT_COMPRESSION) level = 6;
nuclear@26 253 #endif
nuclear@26 254
nuclear@26 255 if (windowBits < 0) { /* suppress zlib wrapper */
nuclear@26 256 wrap = 0;
nuclear@26 257 windowBits = -windowBits;
nuclear@26 258 }
nuclear@26 259 #ifdef GZIP
nuclear@26 260 else if (windowBits > 15) {
nuclear@26 261 wrap = 2; /* write gzip wrapper instead */
nuclear@26 262 windowBits -= 16;
nuclear@26 263 }
nuclear@26 264 #endif
nuclear@26 265 if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
nuclear@26 266 windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
nuclear@26 267 strategy < 0 || strategy > Z_FIXED) {
nuclear@26 268 return Z_STREAM_ERROR;
nuclear@26 269 }
nuclear@26 270 if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
nuclear@26 271 s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
nuclear@26 272 if (s == Z_NULL) return Z_MEM_ERROR;
nuclear@26 273 strm->state = (struct internal_state FAR *)s;
nuclear@26 274 s->strm = strm;
nuclear@26 275
nuclear@26 276 s->wrap = wrap;
nuclear@26 277 s->gzhead = Z_NULL;
nuclear@26 278 s->w_bits = windowBits;
nuclear@26 279 s->w_size = 1 << s->w_bits;
nuclear@26 280 s->w_mask = s->w_size - 1;
nuclear@26 281
nuclear@26 282 s->hash_bits = memLevel + 7;
nuclear@26 283 s->hash_size = 1 << s->hash_bits;
nuclear@26 284 s->hash_mask = s->hash_size - 1;
nuclear@26 285 s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
nuclear@26 286
nuclear@26 287 s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
nuclear@26 288 s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
nuclear@26 289 s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
nuclear@26 290
nuclear@26 291 s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
nuclear@26 292
nuclear@26 293 overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
nuclear@26 294 s->pending_buf = (uchf *) overlay;
nuclear@26 295 s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
nuclear@26 296
nuclear@26 297 if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
nuclear@26 298 s->pending_buf == Z_NULL) {
nuclear@26 299 s->status = FINISH_STATE;
nuclear@26 300 strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
nuclear@26 301 deflateEnd (strm);
nuclear@26 302 return Z_MEM_ERROR;
nuclear@26 303 }
nuclear@26 304 s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
nuclear@26 305 s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
nuclear@26 306
nuclear@26 307 s->level = level;
nuclear@26 308 s->strategy = strategy;
nuclear@26 309 s->method = (Byte)method;
nuclear@26 310
nuclear@26 311 return deflateReset(strm);
nuclear@26 312 }
nuclear@26 313
nuclear@26 314 /* ========================================================================= */
nuclear@26 315 int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
nuclear@26 316 z_streamp strm;
nuclear@26 317 const Bytef *dictionary;
nuclear@26 318 uInt dictLength;
nuclear@26 319 {
nuclear@26 320 deflate_state *s;
nuclear@26 321 uInt length = dictLength;
nuclear@26 322 uInt n;
nuclear@26 323 IPos hash_head = 0;
nuclear@26 324
nuclear@26 325 if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
nuclear@26 326 strm->state->wrap == 2 ||
nuclear@26 327 (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
nuclear@26 328 return Z_STREAM_ERROR;
nuclear@26 329
nuclear@26 330 s = strm->state;
nuclear@26 331 if (s->wrap)
nuclear@26 332 strm->adler = adler32(strm->adler, dictionary, dictLength);
nuclear@26 333
nuclear@26 334 if (length < MIN_MATCH) return Z_OK;
nuclear@26 335 if (length > MAX_DIST(s)) {
nuclear@26 336 length = MAX_DIST(s);
nuclear@26 337 dictionary += dictLength - length; /* use the tail of the dictionary */
nuclear@26 338 }
nuclear@26 339 zmemcpy(s->window, dictionary, length);
nuclear@26 340 s->strstart = length;
nuclear@26 341 s->block_start = (long)length;
nuclear@26 342
nuclear@26 343 /* Insert all strings in the hash table (except for the last two bytes).
nuclear@26 344 * s->lookahead stays null, so s->ins_h will be recomputed at the next
nuclear@26 345 * call of fill_window.
nuclear@26 346 */
nuclear@26 347 s->ins_h = s->window[0];
nuclear@26 348 UPDATE_HASH(s, s->ins_h, s->window[1]);
nuclear@26 349 for (n = 0; n <= length - MIN_MATCH; n++) {
nuclear@26 350 INSERT_STRING(s, n, hash_head);
nuclear@26 351 }
nuclear@26 352 if (hash_head) hash_head = 0; /* to make compiler happy */
nuclear@26 353 return Z_OK;
nuclear@26 354 }
nuclear@26 355
nuclear@26 356 /* ========================================================================= */
nuclear@26 357 int ZEXPORT deflateReset (strm)
nuclear@26 358 z_streamp strm;
nuclear@26 359 {
nuclear@26 360 deflate_state *s;
nuclear@26 361
nuclear@26 362 if (strm == Z_NULL || strm->state == Z_NULL ||
nuclear@26 363 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
nuclear@26 364 return Z_STREAM_ERROR;
nuclear@26 365 }
nuclear@26 366
nuclear@26 367 strm->total_in = strm->total_out = 0;
nuclear@26 368 strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
nuclear@26 369 strm->data_type = Z_UNKNOWN;
nuclear@26 370
nuclear@26 371 s = (deflate_state *)strm->state;
nuclear@26 372 s->pending = 0;
nuclear@26 373 s->pending_out = s->pending_buf;
nuclear@26 374
nuclear@26 375 if (s->wrap < 0) {
nuclear@26 376 s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
nuclear@26 377 }
nuclear@26 378 s->status = s->wrap ? INIT_STATE : BUSY_STATE;
nuclear@26 379 strm->adler =
nuclear@26 380 #ifdef GZIP
nuclear@26 381 s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
nuclear@26 382 #endif
nuclear@26 383 adler32(0L, Z_NULL, 0);
nuclear@26 384 s->last_flush = Z_NO_FLUSH;
nuclear@26 385
nuclear@26 386 _tr_init(s);
nuclear@26 387 lm_init(s);
nuclear@26 388
nuclear@26 389 return Z_OK;
nuclear@26 390 }
nuclear@26 391
nuclear@26 392 /* ========================================================================= */
nuclear@26 393 int ZEXPORT deflateSetHeader (strm, head)
nuclear@26 394 z_streamp strm;
nuclear@26 395 gz_headerp head;
nuclear@26 396 {
nuclear@26 397 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@26 398 if (strm->state->wrap != 2) return Z_STREAM_ERROR;
nuclear@26 399 strm->state->gzhead = head;
nuclear@26 400 return Z_OK;
nuclear@26 401 }
nuclear@26 402
nuclear@26 403 /* ========================================================================= */
nuclear@26 404 int ZEXPORT deflatePrime (strm, bits, value)
nuclear@26 405 z_streamp strm;
nuclear@26 406 int bits;
nuclear@26 407 int value;
nuclear@26 408 {
nuclear@26 409 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@26 410 strm->state->bi_valid = bits;
nuclear@26 411 strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
nuclear@26 412 return Z_OK;
nuclear@26 413 }
nuclear@26 414
nuclear@26 415 /* ========================================================================= */
nuclear@26 416 int ZEXPORT deflateParams(strm, level, strategy)
nuclear@26 417 z_streamp strm;
nuclear@26 418 int level;
nuclear@26 419 int strategy;
nuclear@26 420 {
nuclear@26 421 deflate_state *s;
nuclear@26 422 compress_func func;
nuclear@26 423 int err = Z_OK;
nuclear@26 424
nuclear@26 425 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@26 426 s = strm->state;
nuclear@26 427
nuclear@26 428 #ifdef FASTEST
nuclear@26 429 if (level != 0) level = 1;
nuclear@26 430 #else
nuclear@26 431 if (level == Z_DEFAULT_COMPRESSION) level = 6;
nuclear@26 432 #endif
nuclear@26 433 if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
nuclear@26 434 return Z_STREAM_ERROR;
nuclear@26 435 }
nuclear@26 436 func = configuration_table[s->level].func;
nuclear@26 437
nuclear@26 438 if (func != configuration_table[level].func && strm->total_in != 0) {
nuclear@26 439 /* Flush the last buffer: */
nuclear@26 440 err = deflate(strm, Z_PARTIAL_FLUSH);
nuclear@26 441 }
nuclear@26 442 if (s->level != level) {
nuclear@26 443 s->level = level;
nuclear@26 444 s->max_lazy_match = configuration_table[level].max_lazy;
nuclear@26 445 s->good_match = configuration_table[level].good_length;
nuclear@26 446 s->nice_match = configuration_table[level].nice_length;
nuclear@26 447 s->max_chain_length = configuration_table[level].max_chain;
nuclear@26 448 }
nuclear@26 449 s->strategy = strategy;
nuclear@26 450 return err;
nuclear@26 451 }
nuclear@26 452
nuclear@26 453 /* ========================================================================= */
nuclear@26 454 int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
nuclear@26 455 z_streamp strm;
nuclear@26 456 int good_length;
nuclear@26 457 int max_lazy;
nuclear@26 458 int nice_length;
nuclear@26 459 int max_chain;
nuclear@26 460 {
nuclear@26 461 deflate_state *s;
nuclear@26 462
nuclear@26 463 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@26 464 s = strm->state;
nuclear@26 465 s->good_match = good_length;
nuclear@26 466 s->max_lazy_match = max_lazy;
nuclear@26 467 s->nice_match = nice_length;
nuclear@26 468 s->max_chain_length = max_chain;
nuclear@26 469 return Z_OK;
nuclear@26 470 }
nuclear@26 471
nuclear@26 472 /* =========================================================================
nuclear@26 473 * For the default windowBits of 15 and memLevel of 8, this function returns
nuclear@26 474 * a close to exact, as well as small, upper bound on the compressed size.
nuclear@26 475 * They are coded as constants here for a reason--if the #define's are
nuclear@26 476 * changed, then this function needs to be changed as well. The return
nuclear@26 477 * value for 15 and 8 only works for those exact settings.
nuclear@26 478 *
nuclear@26 479 * For any setting other than those defaults for windowBits and memLevel,
nuclear@26 480 * the value returned is a conservative worst case for the maximum expansion
nuclear@26 481 * resulting from using fixed blocks instead of stored blocks, which deflate
nuclear@26 482 * can emit on compressed data for some combinations of the parameters.
nuclear@26 483 *
nuclear@26 484 * This function could be more sophisticated to provide closer upper bounds
nuclear@26 485 * for every combination of windowBits and memLevel, as well as wrap.
nuclear@26 486 * But even the conservative upper bound of about 14% expansion does not
nuclear@26 487 * seem onerous for output buffer allocation.
nuclear@26 488 */
nuclear@26 489 uLong ZEXPORT deflateBound(strm, sourceLen)
nuclear@26 490 z_streamp strm;
nuclear@26 491 uLong sourceLen;
nuclear@26 492 {
nuclear@26 493 deflate_state *s;
nuclear@26 494 uLong destLen;
nuclear@26 495
nuclear@26 496 /* conservative upper bound */
nuclear@26 497 destLen = sourceLen +
nuclear@26 498 ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
nuclear@26 499
nuclear@26 500 /* if can't get parameters, return conservative bound */
nuclear@26 501 if (strm == Z_NULL || strm->state == Z_NULL)
nuclear@26 502 return destLen;
nuclear@26 503
nuclear@26 504 /* if not default parameters, return conservative bound */
nuclear@26 505 s = strm->state;
nuclear@26 506 if (s->w_bits != 15 || s->hash_bits != 8 + 7)
nuclear@26 507 return destLen;
nuclear@26 508
nuclear@26 509 /* default settings: return tight bound for that case */
nuclear@26 510 return compressBound(sourceLen);
nuclear@26 511 }
nuclear@26 512
nuclear@26 513 /* =========================================================================
nuclear@26 514 * Put a short in the pending buffer. The 16-bit value is put in MSB order.
nuclear@26 515 * IN assertion: the stream state is correct and there is enough room in
nuclear@26 516 * pending_buf.
nuclear@26 517 */
nuclear@26 518 local void putShortMSB (s, b)
nuclear@26 519 deflate_state *s;
nuclear@26 520 uInt b;
nuclear@26 521 {
nuclear@26 522 put_byte(s, (Byte)(b >> 8));
nuclear@26 523 put_byte(s, (Byte)(b & 0xff));
nuclear@26 524 }
nuclear@26 525
nuclear@26 526 /* =========================================================================
nuclear@26 527 * Flush as much pending output as possible. All deflate() output goes
nuclear@26 528 * through this function so some applications may wish to modify it
nuclear@26 529 * to avoid allocating a large strm->next_out buffer and copying into it.
nuclear@26 530 * (See also read_buf()).
nuclear@26 531 */
nuclear@26 532 local void flush_pending(strm)
nuclear@26 533 z_streamp strm;
nuclear@26 534 {
nuclear@26 535 unsigned len = strm->state->pending;
nuclear@26 536
nuclear@26 537 if (len > strm->avail_out) len = strm->avail_out;
nuclear@26 538 if (len == 0) return;
nuclear@26 539
nuclear@26 540 zmemcpy(strm->next_out, strm->state->pending_out, len);
nuclear@26 541 strm->next_out += len;
nuclear@26 542 strm->state->pending_out += len;
nuclear@26 543 strm->total_out += len;
nuclear@26 544 strm->avail_out -= len;
nuclear@26 545 strm->state->pending -= len;
nuclear@26 546 if (strm->state->pending == 0) {
nuclear@26 547 strm->state->pending_out = strm->state->pending_buf;
nuclear@26 548 }
nuclear@26 549 }
nuclear@26 550
nuclear@26 551 /* ========================================================================= */
nuclear@26 552 int ZEXPORT deflate (strm, flush)
nuclear@26 553 z_streamp strm;
nuclear@26 554 int flush;
nuclear@26 555 {
nuclear@26 556 int old_flush; /* value of flush param for previous deflate call */
nuclear@26 557 deflate_state *s;
nuclear@26 558
nuclear@26 559 if (strm == Z_NULL || strm->state == Z_NULL ||
nuclear@26 560 flush > Z_FINISH || flush < 0) {
nuclear@26 561 return Z_STREAM_ERROR;
nuclear@26 562 }
nuclear@26 563 s = strm->state;
nuclear@26 564
nuclear@26 565 if (strm->next_out == Z_NULL ||
nuclear@26 566 (strm->next_in == Z_NULL && strm->avail_in != 0) ||
nuclear@26 567 (s->status == FINISH_STATE && flush != Z_FINISH)) {
nuclear@26 568 ERR_RETURN(strm, Z_STREAM_ERROR);
nuclear@26 569 }
nuclear@26 570 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
nuclear@26 571
nuclear@26 572 s->strm = strm; /* just in case */
nuclear@26 573 old_flush = s->last_flush;
nuclear@26 574 s->last_flush = flush;
nuclear@26 575
nuclear@26 576 /* Write the header */
nuclear@26 577 if (s->status == INIT_STATE) {
nuclear@26 578 #ifdef GZIP
nuclear@26 579 if (s->wrap == 2) {
nuclear@26 580 strm->adler = crc32(0L, Z_NULL, 0);
nuclear@26 581 put_byte(s, 31);
nuclear@26 582 put_byte(s, 139);
nuclear@26 583 put_byte(s, 8);
nuclear@26 584 if (s->gzhead == NULL) {
nuclear@26 585 put_byte(s, 0);
nuclear@26 586 put_byte(s, 0);
nuclear@26 587 put_byte(s, 0);
nuclear@26 588 put_byte(s, 0);
nuclear@26 589 put_byte(s, 0);
nuclear@26 590 put_byte(s, s->level == 9 ? 2 :
nuclear@26 591 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
nuclear@26 592 4 : 0));
nuclear@26 593 put_byte(s, OS_CODE);
nuclear@26 594 s->status = BUSY_STATE;
nuclear@26 595 }
nuclear@26 596 else {
nuclear@26 597 put_byte(s, (s->gzhead->text ? 1 : 0) +
nuclear@26 598 (s->gzhead->hcrc ? 2 : 0) +
nuclear@26 599 (s->gzhead->extra == Z_NULL ? 0 : 4) +
nuclear@26 600 (s->gzhead->name == Z_NULL ? 0 : 8) +
nuclear@26 601 (s->gzhead->comment == Z_NULL ? 0 : 16)
nuclear@26 602 );
nuclear@26 603 put_byte(s, (Byte)(s->gzhead->time & 0xff));
nuclear@26 604 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
nuclear@26 605 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
nuclear@26 606 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
nuclear@26 607 put_byte(s, s->level == 9 ? 2 :
nuclear@26 608 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
nuclear@26 609 4 : 0));
nuclear@26 610 put_byte(s, s->gzhead->os & 0xff);
nuclear@26 611 if (s->gzhead->extra != NULL) {
nuclear@26 612 put_byte(s, s->gzhead->extra_len & 0xff);
nuclear@26 613 put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
nuclear@26 614 }
nuclear@26 615 if (s->gzhead->hcrc)
nuclear@26 616 strm->adler = crc32(strm->adler, s->pending_buf,
nuclear@26 617 s->pending);
nuclear@26 618 s->gzindex = 0;
nuclear@26 619 s->status = EXTRA_STATE;
nuclear@26 620 }
nuclear@26 621 }
nuclear@26 622 else
nuclear@26 623 #endif
nuclear@26 624 {
nuclear@26 625 uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
nuclear@26 626 uInt level_flags;
nuclear@26 627
nuclear@26 628 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
nuclear@26 629 level_flags = 0;
nuclear@26 630 else if (s->level < 6)
nuclear@26 631 level_flags = 1;
nuclear@26 632 else if (s->level == 6)
nuclear@26 633 level_flags = 2;
nuclear@26 634 else
nuclear@26 635 level_flags = 3;
nuclear@26 636 header |= (level_flags << 6);
nuclear@26 637 if (s->strstart != 0) header |= PRESET_DICT;
nuclear@26 638 header += 31 - (header % 31);
nuclear@26 639
nuclear@26 640 s->status = BUSY_STATE;
nuclear@26 641 putShortMSB(s, header);
nuclear@26 642
nuclear@26 643 /* Save the adler32 of the preset dictionary: */
nuclear@26 644 if (s->strstart != 0) {
nuclear@26 645 putShortMSB(s, (uInt)(strm->adler >> 16));
nuclear@26 646 putShortMSB(s, (uInt)(strm->adler & 0xffff));
nuclear@26 647 }
nuclear@26 648 strm->adler = adler32(0L, Z_NULL, 0);
nuclear@26 649 }
nuclear@26 650 }
nuclear@26 651 #ifdef GZIP
nuclear@26 652 if (s->status == EXTRA_STATE) {
nuclear@26 653 if (s->gzhead->extra != NULL) {
nuclear@26 654 uInt beg = s->pending; /* start of bytes to update crc */
nuclear@26 655
nuclear@26 656 while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
nuclear@26 657 if (s->pending == s->pending_buf_size) {
nuclear@26 658 if (s->gzhead->hcrc && s->pending > beg)
nuclear@26 659 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@26 660 s->pending - beg);
nuclear@26 661 flush_pending(strm);
nuclear@26 662 beg = s->pending;
nuclear@26 663 if (s->pending == s->pending_buf_size)
nuclear@26 664 break;
nuclear@26 665 }
nuclear@26 666 put_byte(s, s->gzhead->extra[s->gzindex]);
nuclear@26 667 s->gzindex++;
nuclear@26 668 }
nuclear@26 669 if (s->gzhead->hcrc && s->pending > beg)
nuclear@26 670 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@26 671 s->pending - beg);
nuclear@26 672 if (s->gzindex == s->gzhead->extra_len) {
nuclear@26 673 s->gzindex = 0;
nuclear@26 674 s->status = NAME_STATE;
nuclear@26 675 }
nuclear@26 676 }
nuclear@26 677 else
nuclear@26 678 s->status = NAME_STATE;
nuclear@26 679 }
nuclear@26 680 if (s->status == NAME_STATE) {
nuclear@26 681 if (s->gzhead->name != NULL) {
nuclear@26 682 uInt beg = s->pending; /* start of bytes to update crc */
nuclear@26 683 int val;
nuclear@26 684
nuclear@26 685 do {
nuclear@26 686 if (s->pending == s->pending_buf_size) {
nuclear@26 687 if (s->gzhead->hcrc && s->pending > beg)
nuclear@26 688 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@26 689 s->pending - beg);
nuclear@26 690 flush_pending(strm);
nuclear@26 691 beg = s->pending;
nuclear@26 692 if (s->pending == s->pending_buf_size) {
nuclear@26 693 val = 1;
nuclear@26 694 break;
nuclear@26 695 }
nuclear@26 696 }
nuclear@26 697 val = s->gzhead->name[s->gzindex++];
nuclear@26 698 put_byte(s, val);
nuclear@26 699 } while (val != 0);
nuclear@26 700 if (s->gzhead->hcrc && s->pending > beg)
nuclear@26 701 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@26 702 s->pending - beg);
nuclear@26 703 if (val == 0) {
nuclear@26 704 s->gzindex = 0;
nuclear@26 705 s->status = COMMENT_STATE;
nuclear@26 706 }
nuclear@26 707 }
nuclear@26 708 else
nuclear@26 709 s->status = COMMENT_STATE;
nuclear@26 710 }
nuclear@26 711 if (s->status == COMMENT_STATE) {
nuclear@26 712 if (s->gzhead->comment != NULL) {
nuclear@26 713 uInt beg = s->pending; /* start of bytes to update crc */
nuclear@26 714 int val;
nuclear@26 715
nuclear@26 716 do {
nuclear@26 717 if (s->pending == s->pending_buf_size) {
nuclear@26 718 if (s->gzhead->hcrc && s->pending > beg)
nuclear@26 719 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@26 720 s->pending - beg);
nuclear@26 721 flush_pending(strm);
nuclear@26 722 beg = s->pending;
nuclear@26 723 if (s->pending == s->pending_buf_size) {
nuclear@26 724 val = 1;
nuclear@26 725 break;
nuclear@26 726 }
nuclear@26 727 }
nuclear@26 728 val = s->gzhead->comment[s->gzindex++];
nuclear@26 729 put_byte(s, val);
nuclear@26 730 } while (val != 0);
nuclear@26 731 if (s->gzhead->hcrc && s->pending > beg)
nuclear@26 732 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@26 733 s->pending - beg);
nuclear@26 734 if (val == 0)
nuclear@26 735 s->status = HCRC_STATE;
nuclear@26 736 }
nuclear@26 737 else
nuclear@26 738 s->status = HCRC_STATE;
nuclear@26 739 }
nuclear@26 740 if (s->status == HCRC_STATE) {
nuclear@26 741 if (s->gzhead->hcrc) {
nuclear@26 742 if (s->pending + 2 > s->pending_buf_size)
nuclear@26 743 flush_pending(strm);
nuclear@26 744 if (s->pending + 2 <= s->pending_buf_size) {
nuclear@26 745 put_byte(s, (Byte)(strm->adler & 0xff));
nuclear@26 746 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
nuclear@26 747 strm->adler = crc32(0L, Z_NULL, 0);
nuclear@26 748 s->status = BUSY_STATE;
nuclear@26 749 }
nuclear@26 750 }
nuclear@26 751 else
nuclear@26 752 s->status = BUSY_STATE;
nuclear@26 753 }
nuclear@26 754 #endif
nuclear@26 755
nuclear@26 756 /* Flush as much pending output as possible */
nuclear@26 757 if (s->pending != 0) {
nuclear@26 758 flush_pending(strm);
nuclear@26 759 if (strm->avail_out == 0) {
nuclear@26 760 /* Since avail_out is 0, deflate will be called again with
nuclear@26 761 * more output space, but possibly with both pending and
nuclear@26 762 * avail_in equal to zero. There won't be anything to do,
nuclear@26 763 * but this is not an error situation so make sure we
nuclear@26 764 * return OK instead of BUF_ERROR at next call of deflate:
nuclear@26 765 */
nuclear@26 766 s->last_flush = -1;
nuclear@26 767 return Z_OK;
nuclear@26 768 }
nuclear@26 769
nuclear@26 770 /* Make sure there is something to do and avoid duplicate consecutive
nuclear@26 771 * flushes. For repeated and useless calls with Z_FINISH, we keep
nuclear@26 772 * returning Z_STREAM_END instead of Z_BUF_ERROR.
nuclear@26 773 */
nuclear@26 774 } else if (strm->avail_in == 0 && flush <= old_flush &&
nuclear@26 775 flush != Z_FINISH) {
nuclear@26 776 ERR_RETURN(strm, Z_BUF_ERROR);
nuclear@26 777 }
nuclear@26 778
nuclear@26 779 /* User must not provide more input after the first FINISH: */
nuclear@26 780 if (s->status == FINISH_STATE && strm->avail_in != 0) {
nuclear@26 781 ERR_RETURN(strm, Z_BUF_ERROR);
nuclear@26 782 }
nuclear@26 783
nuclear@26 784 /* Start a new block or continue the current one.
nuclear@26 785 */
nuclear@26 786 if (strm->avail_in != 0 || s->lookahead != 0 ||
nuclear@26 787 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
nuclear@26 788 block_state bstate;
nuclear@26 789
nuclear@26 790 bstate = (*(configuration_table[s->level].func))(s, flush);
nuclear@26 791
nuclear@26 792 if (bstate == finish_started || bstate == finish_done) {
nuclear@26 793 s->status = FINISH_STATE;
nuclear@26 794 }
nuclear@26 795 if (bstate == need_more || bstate == finish_started) {
nuclear@26 796 if (strm->avail_out == 0) {
nuclear@26 797 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
nuclear@26 798 }
nuclear@26 799 return Z_OK;
nuclear@26 800 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
nuclear@26 801 * of deflate should use the same flush parameter to make sure
nuclear@26 802 * that the flush is complete. So we don't have to output an
nuclear@26 803 * empty block here, this will be done at next call. This also
nuclear@26 804 * ensures that for a very small output buffer, we emit at most
nuclear@26 805 * one empty block.
nuclear@26 806 */
nuclear@26 807 }
nuclear@26 808 if (bstate == block_done) {
nuclear@26 809 if (flush == Z_PARTIAL_FLUSH) {
nuclear@26 810 _tr_align(s);
nuclear@26 811 } else { /* FULL_FLUSH or SYNC_FLUSH */
nuclear@26 812 _tr_stored_block(s, (char*)0, 0L, 0);
nuclear@26 813 /* For a full flush, this empty block will be recognized
nuclear@26 814 * as a special marker by inflate_sync().
nuclear@26 815 */
nuclear@26 816 if (flush == Z_FULL_FLUSH) {
nuclear@26 817 CLEAR_HASH(s); /* forget history */
nuclear@26 818 }
nuclear@26 819 }
nuclear@26 820 flush_pending(strm);
nuclear@26 821 if (strm->avail_out == 0) {
nuclear@26 822 s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
nuclear@26 823 return Z_OK;
nuclear@26 824 }
nuclear@26 825 }
nuclear@26 826 }
nuclear@26 827 Assert(strm->avail_out > 0, "bug2");
nuclear@26 828
nuclear@26 829 if (flush != Z_FINISH) return Z_OK;
nuclear@26 830 if (s->wrap <= 0) return Z_STREAM_END;
nuclear@26 831
nuclear@26 832 /* Write the trailer */
nuclear@26 833 #ifdef GZIP
nuclear@26 834 if (s->wrap == 2) {
nuclear@26 835 put_byte(s, (Byte)(strm->adler & 0xff));
nuclear@26 836 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
nuclear@26 837 put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
nuclear@26 838 put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
nuclear@26 839 put_byte(s, (Byte)(strm->total_in & 0xff));
nuclear@26 840 put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
nuclear@26 841 put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
nuclear@26 842 put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
nuclear@26 843 }
nuclear@26 844 else
nuclear@26 845 #endif
nuclear@26 846 {
nuclear@26 847 putShortMSB(s, (uInt)(strm->adler >> 16));
nuclear@26 848 putShortMSB(s, (uInt)(strm->adler & 0xffff));
nuclear@26 849 }
nuclear@26 850 flush_pending(strm);
nuclear@26 851 /* If avail_out is zero, the application will call deflate again
nuclear@26 852 * to flush the rest.
nuclear@26 853 */
nuclear@26 854 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
nuclear@26 855 return s->pending != 0 ? Z_OK : Z_STREAM_END;
nuclear@26 856 }
nuclear@26 857
nuclear@26 858 /* ========================================================================= */
nuclear@26 859 int ZEXPORT deflateEnd (strm)
nuclear@26 860 z_streamp strm;
nuclear@26 861 {
nuclear@26 862 int status;
nuclear@26 863
nuclear@26 864 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@26 865
nuclear@26 866 status = strm->state->status;
nuclear@26 867 if (status != INIT_STATE &&
nuclear@26 868 status != EXTRA_STATE &&
nuclear@26 869 status != NAME_STATE &&
nuclear@26 870 status != COMMENT_STATE &&
nuclear@26 871 status != HCRC_STATE &&
nuclear@26 872 status != BUSY_STATE &&
nuclear@26 873 status != FINISH_STATE) {
nuclear@26 874 return Z_STREAM_ERROR;
nuclear@26 875 }
nuclear@26 876
nuclear@26 877 /* Deallocate in reverse order of allocations: */
nuclear@26 878 TRY_FREE(strm, strm->state->pending_buf);
nuclear@26 879 TRY_FREE(strm, strm->state->head);
nuclear@26 880 TRY_FREE(strm, strm->state->prev);
nuclear@26 881 TRY_FREE(strm, strm->state->window);
nuclear@26 882
nuclear@26 883 ZFREE(strm, strm->state);
nuclear@26 884 strm->state = Z_NULL;
nuclear@26 885
nuclear@26 886 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
nuclear@26 887 }
nuclear@26 888
nuclear@26 889 /* =========================================================================
nuclear@26 890 * Copy the source state to the destination state.
nuclear@26 891 * To simplify the source, this is not supported for 16-bit MSDOS (which
nuclear@26 892 * doesn't have enough memory anyway to duplicate compression states).
nuclear@26 893 */
nuclear@26 894 int ZEXPORT deflateCopy (dest, source)
nuclear@26 895 z_streamp dest;
nuclear@26 896 z_streamp source;
nuclear@26 897 {
nuclear@26 898 #ifdef MAXSEG_64K
nuclear@26 899 return Z_STREAM_ERROR;
nuclear@26 900 #else
nuclear@26 901 deflate_state *ds;
nuclear@26 902 deflate_state *ss;
nuclear@26 903 ushf *overlay;
nuclear@26 904
nuclear@26 905
nuclear@26 906 if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
nuclear@26 907 return Z_STREAM_ERROR;
nuclear@26 908 }
nuclear@26 909
nuclear@26 910 ss = source->state;
nuclear@26 911
nuclear@26 912 zmemcpy(dest, source, sizeof(z_stream));
nuclear@26 913
nuclear@26 914 ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
nuclear@26 915 if (ds == Z_NULL) return Z_MEM_ERROR;
nuclear@26 916 dest->state = (struct internal_state FAR *) ds;
nuclear@26 917 zmemcpy(ds, ss, sizeof(deflate_state));
nuclear@26 918 ds->strm = dest;
nuclear@26 919
nuclear@26 920 ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
nuclear@26 921 ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
nuclear@26 922 ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
nuclear@26 923 overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
nuclear@26 924 ds->pending_buf = (uchf *) overlay;
nuclear@26 925
nuclear@26 926 if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
nuclear@26 927 ds->pending_buf == Z_NULL) {
nuclear@26 928 deflateEnd (dest);
nuclear@26 929 return Z_MEM_ERROR;
nuclear@26 930 }
nuclear@26 931 /* following zmemcpy do not work for 16-bit MSDOS */
nuclear@26 932 zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
nuclear@26 933 zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
nuclear@26 934 zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
nuclear@26 935 zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
nuclear@26 936
nuclear@26 937 ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
nuclear@26 938 ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
nuclear@26 939 ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
nuclear@26 940
nuclear@26 941 ds->l_desc.dyn_tree = ds->dyn_ltree;
nuclear@26 942 ds->d_desc.dyn_tree = ds->dyn_dtree;
nuclear@26 943 ds->bl_desc.dyn_tree = ds->bl_tree;
nuclear@26 944
nuclear@26 945 return Z_OK;
nuclear@26 946 #endif /* MAXSEG_64K */
nuclear@26 947 }
nuclear@26 948
nuclear@26 949 /* ===========================================================================
nuclear@26 950 * Read a new buffer from the current input stream, update the adler32
nuclear@26 951 * and total number of bytes read. All deflate() input goes through
nuclear@26 952 * this function so some applications may wish to modify it to avoid
nuclear@26 953 * allocating a large strm->next_in buffer and copying from it.
nuclear@26 954 * (See also flush_pending()).
nuclear@26 955 */
nuclear@26 956 local int read_buf(strm, buf, size)
nuclear@26 957 z_streamp strm;
nuclear@26 958 Bytef *buf;
nuclear@26 959 unsigned size;
nuclear@26 960 {
nuclear@26 961 unsigned len = strm->avail_in;
nuclear@26 962
nuclear@26 963 if (len > size) len = size;
nuclear@26 964 if (len == 0) return 0;
nuclear@26 965
nuclear@26 966 strm->avail_in -= len;
nuclear@26 967
nuclear@26 968 if (strm->state->wrap == 1) {
nuclear@26 969 strm->adler = adler32(strm->adler, strm->next_in, len);
nuclear@26 970 }
nuclear@26 971 #ifdef GZIP
nuclear@26 972 else if (strm->state->wrap == 2) {
nuclear@26 973 strm->adler = crc32(strm->adler, strm->next_in, len);
nuclear@26 974 }
nuclear@26 975 #endif
nuclear@26 976 zmemcpy(buf, strm->next_in, len);
nuclear@26 977 strm->next_in += len;
nuclear@26 978 strm->total_in += len;
nuclear@26 979
nuclear@26 980 return (int)len;
nuclear@26 981 }
nuclear@26 982
nuclear@26 983 /* ===========================================================================
nuclear@26 984 * Initialize the "longest match" routines for a new zlib stream
nuclear@26 985 */
nuclear@26 986 local void lm_init (s)
nuclear@26 987 deflate_state *s;
nuclear@26 988 {
nuclear@26 989 s->window_size = (ulg)2L*s->w_size;
nuclear@26 990
nuclear@26 991 CLEAR_HASH(s);
nuclear@26 992
nuclear@26 993 /* Set the default configuration parameters:
nuclear@26 994 */
nuclear@26 995 s->max_lazy_match = configuration_table[s->level].max_lazy;
nuclear@26 996 s->good_match = configuration_table[s->level].good_length;
nuclear@26 997 s->nice_match = configuration_table[s->level].nice_length;
nuclear@26 998 s->max_chain_length = configuration_table[s->level].max_chain;
nuclear@26 999
nuclear@26 1000 s->strstart = 0;
nuclear@26 1001 s->block_start = 0L;
nuclear@26 1002 s->lookahead = 0;
nuclear@26 1003 s->match_length = s->prev_length = MIN_MATCH-1;
nuclear@26 1004 s->match_available = 0;
nuclear@26 1005 s->ins_h = 0;
nuclear@26 1006 #ifndef FASTEST
nuclear@26 1007 #ifdef ASMV
nuclear@26 1008 match_init(); /* initialize the asm code */
nuclear@26 1009 #endif
nuclear@26 1010 #endif
nuclear@26 1011 }
nuclear@26 1012
nuclear@26 1013 #ifndef FASTEST
nuclear@26 1014 /* ===========================================================================
nuclear@26 1015 * Set match_start to the longest match starting at the given string and
nuclear@26 1016 * return its length. Matches shorter or equal to prev_length are discarded,
nuclear@26 1017 * in which case the result is equal to prev_length and match_start is
nuclear@26 1018 * garbage.
nuclear@26 1019 * IN assertions: cur_match is the head of the hash chain for the current
nuclear@26 1020 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
nuclear@26 1021 * OUT assertion: the match length is not greater than s->lookahead.
nuclear@26 1022 */
nuclear@26 1023 #ifndef ASMV
nuclear@26 1024 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
nuclear@26 1025 * match.S. The code will be functionally equivalent.
nuclear@26 1026 */
nuclear@26 1027 local uInt longest_match(s, cur_match)
nuclear@26 1028 deflate_state *s;
nuclear@26 1029 IPos cur_match; /* current match */
nuclear@26 1030 {
nuclear@26 1031 unsigned chain_length = s->max_chain_length;/* max hash chain length */
nuclear@26 1032 register Bytef *scan = s->window + s->strstart; /* current string */
nuclear@26 1033 register Bytef *match; /* matched string */
nuclear@26 1034 register int len; /* length of current match */
nuclear@26 1035 int best_len = s->prev_length; /* best match length so far */
nuclear@26 1036 int nice_match = s->nice_match; /* stop if match long enough */
nuclear@26 1037 IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
nuclear@26 1038 s->strstart - (IPos)MAX_DIST(s) : NIL;
nuclear@26 1039 /* Stop when cur_match becomes <= limit. To simplify the code,
nuclear@26 1040 * we prevent matches with the string of window index 0.
nuclear@26 1041 */
nuclear@26 1042 Posf *prev = s->prev;
nuclear@26 1043 uInt wmask = s->w_mask;
nuclear@26 1044
nuclear@26 1045 #ifdef UNALIGNED_OK
nuclear@26 1046 /* Compare two bytes at a time. Note: this is not always beneficial.
nuclear@26 1047 * Try with and without -DUNALIGNED_OK to check.
nuclear@26 1048 */
nuclear@26 1049 register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
nuclear@26 1050 register ush scan_start = *(ushf*)scan;
nuclear@26 1051 register ush scan_end = *(ushf*)(scan+best_len-1);
nuclear@26 1052 #else
nuclear@26 1053 register Bytef *strend = s->window + s->strstart + MAX_MATCH;
nuclear@26 1054 register Byte scan_end1 = scan[best_len-1];
nuclear@26 1055 register Byte scan_end = scan[best_len];
nuclear@26 1056 #endif
nuclear@26 1057
nuclear@26 1058 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
nuclear@26 1059 * It is easy to get rid of this optimization if necessary.
nuclear@26 1060 */
nuclear@26 1061 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
nuclear@26 1062
nuclear@26 1063 /* Do not waste too much time if we already have a good match: */
nuclear@26 1064 if (s->prev_length >= s->good_match) {
nuclear@26 1065 chain_length >>= 2;
nuclear@26 1066 }
nuclear@26 1067 /* Do not look for matches beyond the end of the input. This is necessary
nuclear@26 1068 * to make deflate deterministic.
nuclear@26 1069 */
nuclear@26 1070 if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
nuclear@26 1071
nuclear@26 1072 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
nuclear@26 1073
nuclear@26 1074 do {
nuclear@26 1075 Assert(cur_match < s->strstart, "no future");
nuclear@26 1076 match = s->window + cur_match;
nuclear@26 1077
nuclear@26 1078 /* Skip to next match if the match length cannot increase
nuclear@26 1079 * or if the match length is less than 2. Note that the checks below
nuclear@26 1080 * for insufficient lookahead only occur occasionally for performance
nuclear@26 1081 * reasons. Therefore uninitialized memory will be accessed, and
nuclear@26 1082 * conditional jumps will be made that depend on those values.
nuclear@26 1083 * However the length of the match is limited to the lookahead, so
nuclear@26 1084 * the output of deflate is not affected by the uninitialized values.
nuclear@26 1085 */
nuclear@26 1086 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
nuclear@26 1087 /* This code assumes sizeof(unsigned short) == 2. Do not use
nuclear@26 1088 * UNALIGNED_OK if your compiler uses a different size.
nuclear@26 1089 */
nuclear@26 1090 if (*(ushf*)(match+best_len-1) != scan_end ||
nuclear@26 1091 *(ushf*)match != scan_start) continue;
nuclear@26 1092
nuclear@26 1093 /* It is not necessary to compare scan[2] and match[2] since they are
nuclear@26 1094 * always equal when the other bytes match, given that the hash keys
nuclear@26 1095 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
nuclear@26 1096 * strstart+3, +5, ... up to strstart+257. We check for insufficient
nuclear@26 1097 * lookahead only every 4th comparison; the 128th check will be made
nuclear@26 1098 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
nuclear@26 1099 * necessary to put more guard bytes at the end of the window, or
nuclear@26 1100 * to check more often for insufficient lookahead.
nuclear@26 1101 */
nuclear@26 1102 Assert(scan[2] == match[2], "scan[2]?");
nuclear@26 1103 scan++, match++;
nuclear@26 1104 do {
nuclear@26 1105 } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
nuclear@26 1106 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
nuclear@26 1107 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
nuclear@26 1108 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
nuclear@26 1109 scan < strend);
nuclear@26 1110 /* The funny "do {}" generates better code on most compilers */
nuclear@26 1111
nuclear@26 1112 /* Here, scan <= window+strstart+257 */
nuclear@26 1113 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
nuclear@26 1114 if (*scan == *match) scan++;
nuclear@26 1115
nuclear@26 1116 len = (MAX_MATCH - 1) - (int)(strend-scan);
nuclear@26 1117 scan = strend - (MAX_MATCH-1);
nuclear@26 1118
nuclear@26 1119 #else /* UNALIGNED_OK */
nuclear@26 1120
nuclear@26 1121 if (match[best_len] != scan_end ||
nuclear@26 1122 match[best_len-1] != scan_end1 ||
nuclear@26 1123 *match != *scan ||
nuclear@26 1124 *++match != scan[1]) continue;
nuclear@26 1125
nuclear@26 1126 /* The check at best_len-1 can be removed because it will be made
nuclear@26 1127 * again later. (This heuristic is not always a win.)
nuclear@26 1128 * It is not necessary to compare scan[2] and match[2] since they
nuclear@26 1129 * are always equal when the other bytes match, given that
nuclear@26 1130 * the hash keys are equal and that HASH_BITS >= 8.
nuclear@26 1131 */
nuclear@26 1132 scan += 2, match++;
nuclear@26 1133 Assert(*scan == *match, "match[2]?");
nuclear@26 1134
nuclear@26 1135 /* We check for insufficient lookahead only every 8th comparison;
nuclear@26 1136 * the 256th check will be made at strstart+258.
nuclear@26 1137 */
nuclear@26 1138 do {
nuclear@26 1139 } while (*++scan == *++match && *++scan == *++match &&
nuclear@26 1140 *++scan == *++match && *++scan == *++match &&
nuclear@26 1141 *++scan == *++match && *++scan == *++match &&
nuclear@26 1142 *++scan == *++match && *++scan == *++match &&
nuclear@26 1143 scan < strend);
nuclear@26 1144
nuclear@26 1145 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
nuclear@26 1146
nuclear@26 1147 len = MAX_MATCH - (int)(strend - scan);
nuclear@26 1148 scan = strend - MAX_MATCH;
nuclear@26 1149
nuclear@26 1150 #endif /* UNALIGNED_OK */
nuclear@26 1151
nuclear@26 1152 if (len > best_len) {
nuclear@26 1153 s->match_start = cur_match;
nuclear@26 1154 best_len = len;
nuclear@26 1155 if (len >= nice_match) break;
nuclear@26 1156 #ifdef UNALIGNED_OK
nuclear@26 1157 scan_end = *(ushf*)(scan+best_len-1);
nuclear@26 1158 #else
nuclear@26 1159 scan_end1 = scan[best_len-1];
nuclear@26 1160 scan_end = scan[best_len];
nuclear@26 1161 #endif
nuclear@26 1162 }
nuclear@26 1163 } while ((cur_match = prev[cur_match & wmask]) > limit
nuclear@26 1164 && --chain_length != 0);
nuclear@26 1165
nuclear@26 1166 if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
nuclear@26 1167 return s->lookahead;
nuclear@26 1168 }
nuclear@26 1169 #endif /* ASMV */
nuclear@26 1170 #endif /* FASTEST */
nuclear@26 1171
nuclear@26 1172 /* ---------------------------------------------------------------------------
nuclear@26 1173 * Optimized version for level == 1 or strategy == Z_RLE only
nuclear@26 1174 */
nuclear@26 1175 local uInt longest_match_fast(s, cur_match)
nuclear@26 1176 deflate_state *s;
nuclear@26 1177 IPos cur_match; /* current match */
nuclear@26 1178 {
nuclear@26 1179 register Bytef *scan = s->window + s->strstart; /* current string */
nuclear@26 1180 register Bytef *match; /* matched string */
nuclear@26 1181 register int len; /* length of current match */
nuclear@26 1182 register Bytef *strend = s->window + s->strstart + MAX_MATCH;
nuclear@26 1183
nuclear@26 1184 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
nuclear@26 1185 * It is easy to get rid of this optimization if necessary.
nuclear@26 1186 */
nuclear@26 1187 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
nuclear@26 1188
nuclear@26 1189 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
nuclear@26 1190
nuclear@26 1191 Assert(cur_match < s->strstart, "no future");
nuclear@26 1192
nuclear@26 1193 match = s->window + cur_match;
nuclear@26 1194
nuclear@26 1195 /* Return failure if the match length is less than 2:
nuclear@26 1196 */
nuclear@26 1197 if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
nuclear@26 1198
nuclear@26 1199 /* The check at best_len-1 can be removed because it will be made
nuclear@26 1200 * again later. (This heuristic is not always a win.)
nuclear@26 1201 * It is not necessary to compare scan[2] and match[2] since they
nuclear@26 1202 * are always equal when the other bytes match, given that
nuclear@26 1203 * the hash keys are equal and that HASH_BITS >= 8.
nuclear@26 1204 */
nuclear@26 1205 scan += 2, match += 2;
nuclear@26 1206 Assert(*scan == *match, "match[2]?");
nuclear@26 1207
nuclear@26 1208 /* We check for insufficient lookahead only every 8th comparison;
nuclear@26 1209 * the 256th check will be made at strstart+258.
nuclear@26 1210 */
nuclear@26 1211 do {
nuclear@26 1212 } while (*++scan == *++match && *++scan == *++match &&
nuclear@26 1213 *++scan == *++match && *++scan == *++match &&
nuclear@26 1214 *++scan == *++match && *++scan == *++match &&
nuclear@26 1215 *++scan == *++match && *++scan == *++match &&
nuclear@26 1216 scan < strend);
nuclear@26 1217
nuclear@26 1218 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
nuclear@26 1219
nuclear@26 1220 len = MAX_MATCH - (int)(strend - scan);
nuclear@26 1221
nuclear@26 1222 if (len < MIN_MATCH) return MIN_MATCH - 1;
nuclear@26 1223
nuclear@26 1224 s->match_start = cur_match;
nuclear@26 1225 return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
nuclear@26 1226 }
nuclear@26 1227
nuclear@26 1228 #ifdef DEBUG
nuclear@26 1229 /* ===========================================================================
nuclear@26 1230 * Check that the match at match_start is indeed a match.
nuclear@26 1231 */
nuclear@26 1232 local void check_match(s, start, match, length)
nuclear@26 1233 deflate_state *s;
nuclear@26 1234 IPos start, match;
nuclear@26 1235 int length;
nuclear@26 1236 {
nuclear@26 1237 /* check that the match is indeed a match */
nuclear@26 1238 if (zmemcmp(s->window + match,
nuclear@26 1239 s->window + start, length) != EQUAL) {
nuclear@26 1240 fprintf(stderr, " start %u, match %u, length %d\n",
nuclear@26 1241 start, match, length);
nuclear@26 1242 do {
nuclear@26 1243 fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
nuclear@26 1244 } while (--length != 0);
nuclear@26 1245 z_error("invalid match");
nuclear@26 1246 }
nuclear@26 1247 if (z_verbose > 1) {
nuclear@26 1248 fprintf(stderr,"\\[%d,%d]", start-match, length);
nuclear@26 1249 do { putc(s->window[start++], stderr); } while (--length != 0);
nuclear@26 1250 }
nuclear@26 1251 }
nuclear@26 1252 #else
nuclear@26 1253 # define check_match(s, start, match, length)
nuclear@26 1254 #endif /* DEBUG */
nuclear@26 1255
nuclear@26 1256 /* ===========================================================================
nuclear@26 1257 * Fill the window when the lookahead becomes insufficient.
nuclear@26 1258 * Updates strstart and lookahead.
nuclear@26 1259 *
nuclear@26 1260 * IN assertion: lookahead < MIN_LOOKAHEAD
nuclear@26 1261 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
nuclear@26 1262 * At least one byte has been read, or avail_in == 0; reads are
nuclear@26 1263 * performed for at least two bytes (required for the zip translate_eol
nuclear@26 1264 * option -- not supported here).
nuclear@26 1265 */
nuclear@26 1266 local void fill_window(s)
nuclear@26 1267 deflate_state *s;
nuclear@26 1268 {
nuclear@26 1269 register unsigned n, m;
nuclear@26 1270 register Posf *p;
nuclear@26 1271 unsigned more; /* Amount of free space at the end of the window. */
nuclear@26 1272 uInt wsize = s->w_size;
nuclear@26 1273
nuclear@26 1274 do {
nuclear@26 1275 more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
nuclear@26 1276
nuclear@26 1277 /* Deal with !@#$% 64K limit: */
nuclear@26 1278 if (sizeof(int) <= 2) {
nuclear@26 1279 if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
nuclear@26 1280 more = wsize;
nuclear@26 1281
nuclear@26 1282 } else if (more == (unsigned)(-1)) {
nuclear@26 1283 /* Very unlikely, but possible on 16 bit machine if
nuclear@26 1284 * strstart == 0 && lookahead == 1 (input done a byte at time)
nuclear@26 1285 */
nuclear@26 1286 more--;
nuclear@26 1287 }
nuclear@26 1288 }
nuclear@26 1289
nuclear@26 1290 /* If the window is almost full and there is insufficient lookahead,
nuclear@26 1291 * move the upper half to the lower one to make room in the upper half.
nuclear@26 1292 */
nuclear@26 1293 if (s->strstart >= wsize+MAX_DIST(s)) {
nuclear@26 1294
nuclear@26 1295 zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
nuclear@26 1296 s->match_start -= wsize;
nuclear@26 1297 s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
nuclear@26 1298 s->block_start -= (long) wsize;
nuclear@26 1299
nuclear@26 1300 /* Slide the hash table (could be avoided with 32 bit values
nuclear@26 1301 at the expense of memory usage). We slide even when level == 0
nuclear@26 1302 to keep the hash table consistent if we switch back to level > 0
nuclear@26 1303 later. (Using level 0 permanently is not an optimal usage of
nuclear@26 1304 zlib, so we don't care about this pathological case.)
nuclear@26 1305 */
nuclear@26 1306 /* %%% avoid this when Z_RLE */
nuclear@26 1307 n = s->hash_size;
nuclear@26 1308 p = &s->head[n];
nuclear@26 1309 do {
nuclear@26 1310 m = *--p;
nuclear@26 1311 *p = (Pos)(m >= wsize ? m-wsize : NIL);
nuclear@26 1312 } while (--n);
nuclear@26 1313
nuclear@26 1314 n = wsize;
nuclear@26 1315 #ifndef FASTEST
nuclear@26 1316 p = &s->prev[n];
nuclear@26 1317 do {
nuclear@26 1318 m = *--p;
nuclear@26 1319 *p = (Pos)(m >= wsize ? m-wsize : NIL);
nuclear@26 1320 /* If n is not on any hash chain, prev[n] is garbage but
nuclear@26 1321 * its value will never be used.
nuclear@26 1322 */
nuclear@26 1323 } while (--n);
nuclear@26 1324 #endif
nuclear@26 1325 more += wsize;
nuclear@26 1326 }
nuclear@26 1327 if (s->strm->avail_in == 0) return;
nuclear@26 1328
nuclear@26 1329 /* If there was no sliding:
nuclear@26 1330 * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
nuclear@26 1331 * more == window_size - lookahead - strstart
nuclear@26 1332 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
nuclear@26 1333 * => more >= window_size - 2*WSIZE + 2
nuclear@26 1334 * In the BIG_MEM or MMAP case (not yet supported),
nuclear@26 1335 * window_size == input_size + MIN_LOOKAHEAD &&
nuclear@26 1336 * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
nuclear@26 1337 * Otherwise, window_size == 2*WSIZE so more >= 2.
nuclear@26 1338 * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
nuclear@26 1339 */
nuclear@26 1340 Assert(more >= 2, "more < 2");
nuclear@26 1341
nuclear@26 1342 n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
nuclear@26 1343 s->lookahead += n;
nuclear@26 1344
nuclear@26 1345 /* Initialize the hash value now that we have some input: */
nuclear@26 1346 if (s->lookahead >= MIN_MATCH) {
nuclear@26 1347 s->ins_h = s->window[s->strstart];
nuclear@26 1348 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
nuclear@26 1349 #if MIN_MATCH != 3
nuclear@26 1350 Call UPDATE_HASH() MIN_MATCH-3 more times
nuclear@26 1351 #endif
nuclear@26 1352 }
nuclear@26 1353 /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
nuclear@26 1354 * but this is not important since only literal bytes will be emitted.
nuclear@26 1355 */
nuclear@26 1356
nuclear@26 1357 } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
nuclear@26 1358 }
nuclear@26 1359
nuclear@26 1360 /* ===========================================================================
nuclear@26 1361 * Flush the current block, with given end-of-file flag.
nuclear@26 1362 * IN assertion: strstart is set to the end of the current match.
nuclear@26 1363 */
nuclear@26 1364 #define FLUSH_BLOCK_ONLY(s, eof) { \
nuclear@26 1365 _tr_flush_block(s, (s->block_start >= 0L ? \
nuclear@26 1366 (charf *)&s->window[(unsigned)s->block_start] : \
nuclear@26 1367 (charf *)Z_NULL), \
nuclear@26 1368 (ulg)((long)s->strstart - s->block_start), \
nuclear@26 1369 (eof)); \
nuclear@26 1370 s->block_start = s->strstart; \
nuclear@26 1371 flush_pending(s->strm); \
nuclear@26 1372 Tracev((stderr,"[FLUSH]")); \
nuclear@26 1373 }
nuclear@26 1374
nuclear@26 1375 /* Same but force premature exit if necessary. */
nuclear@26 1376 #define FLUSH_BLOCK(s, eof) { \
nuclear@26 1377 FLUSH_BLOCK_ONLY(s, eof); \
nuclear@26 1378 if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
nuclear@26 1379 }
nuclear@26 1380
nuclear@26 1381 /* ===========================================================================
nuclear@26 1382 * Copy without compression as much as possible from the input stream, return
nuclear@26 1383 * the current block state.
nuclear@26 1384 * This function does not insert new strings in the dictionary since
nuclear@26 1385 * uncompressible data is probably not useful. This function is used
nuclear@26 1386 * only for the level=0 compression option.
nuclear@26 1387 * NOTE: this function should be optimized to avoid extra copying from
nuclear@26 1388 * window to pending_buf.
nuclear@26 1389 */
nuclear@26 1390 local block_state deflate_stored(s, flush)
nuclear@26 1391 deflate_state *s;
nuclear@26 1392 int flush;
nuclear@26 1393 {
nuclear@26 1394 /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
nuclear@26 1395 * to pending_buf_size, and each stored block has a 5 byte header:
nuclear@26 1396 */
nuclear@26 1397 ulg max_block_size = 0xffff;
nuclear@26 1398 ulg max_start;
nuclear@26 1399
nuclear@26 1400 if (max_block_size > s->pending_buf_size - 5) {
nuclear@26 1401 max_block_size = s->pending_buf_size - 5;
nuclear@26 1402 }
nuclear@26 1403
nuclear@26 1404 /* Copy as much as possible from input to output: */
nuclear@26 1405 for (;;) {
nuclear@26 1406 /* Fill the window as much as possible: */
nuclear@26 1407 if (s->lookahead <= 1) {
nuclear@26 1408
nuclear@26 1409 Assert(s->strstart < s->w_size+MAX_DIST(s) ||
nuclear@26 1410 s->block_start >= (long)s->w_size, "slide too late");
nuclear@26 1411
nuclear@26 1412 fill_window(s);
nuclear@26 1413 if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
nuclear@26 1414
nuclear@26 1415 if (s->lookahead == 0) break; /* flush the current block */
nuclear@26 1416 }
nuclear@26 1417 Assert(s->block_start >= 0L, "block gone");
nuclear@26 1418
nuclear@26 1419 s->strstart += s->lookahead;
nuclear@26 1420 s->lookahead = 0;
nuclear@26 1421
nuclear@26 1422 /* Emit a stored block if pending_buf will be full: */
nuclear@26 1423 max_start = s->block_start + max_block_size;
nuclear@26 1424 if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
nuclear@26 1425 /* strstart == 0 is possible when wraparound on 16-bit machine */
nuclear@26 1426 s->lookahead = (uInt)(s->strstart - max_start);
nuclear@26 1427 s->strstart = (uInt)max_start;
nuclear@26 1428 FLUSH_BLOCK(s, 0);
nuclear@26 1429 }
nuclear@26 1430 /* Flush if we may have to slide, otherwise block_start may become
nuclear@26 1431 * negative and the data will be gone:
nuclear@26 1432 */
nuclear@26 1433 if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
nuclear@26 1434 FLUSH_BLOCK(s, 0);
nuclear@26 1435 }
nuclear@26 1436 }
nuclear@26 1437 FLUSH_BLOCK(s, flush == Z_FINISH);
nuclear@26 1438 return flush == Z_FINISH ? finish_done : block_done;
nuclear@26 1439 }
nuclear@26 1440
nuclear@26 1441 /* ===========================================================================
nuclear@26 1442 * Compress as much as possible from the input stream, return the current
nuclear@26 1443 * block state.
nuclear@26 1444 * This function does not perform lazy evaluation of matches and inserts
nuclear@26 1445 * new strings in the dictionary only for unmatched strings or for short
nuclear@26 1446 * matches. It is used only for the fast compression options.
nuclear@26 1447 */
nuclear@26 1448 local block_state deflate_fast(s, flush)
nuclear@26 1449 deflate_state *s;
nuclear@26 1450 int flush;
nuclear@26 1451 {
nuclear@26 1452 IPos hash_head = NIL; /* head of the hash chain */
nuclear@26 1453 int bflush; /* set if current block must be flushed */
nuclear@26 1454
nuclear@26 1455 for (;;) {
nuclear@26 1456 /* Make sure that we always have enough lookahead, except
nuclear@26 1457 * at the end of the input file. We need MAX_MATCH bytes
nuclear@26 1458 * for the next match, plus MIN_MATCH bytes to insert the
nuclear@26 1459 * string following the next match.
nuclear@26 1460 */
nuclear@26 1461 if (s->lookahead < MIN_LOOKAHEAD) {
nuclear@26 1462 fill_window(s);
nuclear@26 1463 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
nuclear@26 1464 return need_more;
nuclear@26 1465 }
nuclear@26 1466 if (s->lookahead == 0) break; /* flush the current block */
nuclear@26 1467 }
nuclear@26 1468
nuclear@26 1469 /* Insert the string window[strstart .. strstart+2] in the
nuclear@26 1470 * dictionary, and set hash_head to the head of the hash chain:
nuclear@26 1471 */
nuclear@26 1472 if (s->lookahead >= MIN_MATCH) {
nuclear@26 1473 INSERT_STRING(s, s->strstart, hash_head);
nuclear@26 1474 }
nuclear@26 1475
nuclear@26 1476 /* Find the longest match, discarding those <= prev_length.
nuclear@26 1477 * At this point we have always match_length < MIN_MATCH
nuclear@26 1478 */
nuclear@26 1479 if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
nuclear@26 1480 /* To simplify the code, we prevent matches with the string
nuclear@26 1481 * of window index 0 (in particular we have to avoid a match
nuclear@26 1482 * of the string with itself at the start of the input file).
nuclear@26 1483 */
nuclear@26 1484 #ifdef FASTEST
nuclear@26 1485 if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) ||
nuclear@26 1486 (s->strategy == Z_RLE && s->strstart - hash_head == 1)) {
nuclear@26 1487 s->match_length = longest_match_fast (s, hash_head);
nuclear@26 1488 }
nuclear@26 1489 #else
nuclear@26 1490 if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
nuclear@26 1491 s->match_length = longest_match (s, hash_head);
nuclear@26 1492 } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
nuclear@26 1493 s->match_length = longest_match_fast (s, hash_head);
nuclear@26 1494 }
nuclear@26 1495 #endif
nuclear@26 1496 /* longest_match() or longest_match_fast() sets match_start */
nuclear@26 1497 }
nuclear@26 1498 if (s->match_length >= MIN_MATCH) {
nuclear@26 1499 check_match(s, s->strstart, s->match_start, s->match_length);
nuclear@26 1500
nuclear@26 1501 _tr_tally_dist(s, s->strstart - s->match_start,
nuclear@26 1502 s->match_length - MIN_MATCH, bflush);
nuclear@26 1503
nuclear@26 1504 s->lookahead -= s->match_length;
nuclear@26 1505
nuclear@26 1506 /* Insert new strings in the hash table only if the match length
nuclear@26 1507 * is not too large. This saves time but degrades compression.
nuclear@26 1508 */
nuclear@26 1509 #ifndef FASTEST
nuclear@26 1510 if (s->match_length <= s->max_insert_length &&
nuclear@26 1511 s->lookahead >= MIN_MATCH) {
nuclear@26 1512 s->match_length--; /* string at strstart already in table */
nuclear@26 1513 do {
nuclear@26 1514 s->strstart++;
nuclear@26 1515 INSERT_STRING(s, s->strstart, hash_head);
nuclear@26 1516 /* strstart never exceeds WSIZE-MAX_MATCH, so there are
nuclear@26 1517 * always MIN_MATCH bytes ahead.
nuclear@26 1518 */
nuclear@26 1519 } while (--s->match_length != 0);
nuclear@26 1520 s->strstart++;
nuclear@26 1521 } else
nuclear@26 1522 #endif
nuclear@26 1523 {
nuclear@26 1524 s->strstart += s->match_length;
nuclear@26 1525 s->match_length = 0;
nuclear@26 1526 s->ins_h = s->window[s->strstart];
nuclear@26 1527 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
nuclear@26 1528 #if MIN_MATCH != 3
nuclear@26 1529 Call UPDATE_HASH() MIN_MATCH-3 more times
nuclear@26 1530 #endif
nuclear@26 1531 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
nuclear@26 1532 * matter since it will be recomputed at next deflate call.
nuclear@26 1533 */
nuclear@26 1534 }
nuclear@26 1535 } else {
nuclear@26 1536 /* No match, output a literal byte */
nuclear@26 1537 Tracevv((stderr,"%c", s->window[s->strstart]));
nuclear@26 1538 _tr_tally_lit (s, s->window[s->strstart], bflush);
nuclear@26 1539 s->lookahead--;
nuclear@26 1540 s->strstart++;
nuclear@26 1541 }
nuclear@26 1542 if (bflush) FLUSH_BLOCK(s, 0);
nuclear@26 1543 }
nuclear@26 1544 FLUSH_BLOCK(s, flush == Z_FINISH);
nuclear@26 1545 return flush == Z_FINISH ? finish_done : block_done;
nuclear@26 1546 }
nuclear@26 1547
nuclear@26 1548 #ifndef FASTEST
nuclear@26 1549 /* ===========================================================================
nuclear@26 1550 * Same as above, but achieves better compression. We use a lazy
nuclear@26 1551 * evaluation for matches: a match is finally adopted only if there is
nuclear@26 1552 * no better match at the next window position.
nuclear@26 1553 */
nuclear@26 1554 local block_state deflate_slow(s, flush)
nuclear@26 1555 deflate_state *s;
nuclear@26 1556 int flush;
nuclear@26 1557 {
nuclear@26 1558 IPos hash_head = NIL; /* head of hash chain */
nuclear@26 1559 int bflush; /* set if current block must be flushed */
nuclear@26 1560
nuclear@26 1561 /* Process the input block. */
nuclear@26 1562 for (;;) {
nuclear@26 1563 /* Make sure that we always have enough lookahead, except
nuclear@26 1564 * at the end of the input file. We need MAX_MATCH bytes
nuclear@26 1565 * for the next match, plus MIN_MATCH bytes to insert the
nuclear@26 1566 * string following the next match.
nuclear@26 1567 */
nuclear@26 1568 if (s->lookahead < MIN_LOOKAHEAD) {
nuclear@26 1569 fill_window(s);
nuclear@26 1570 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
nuclear@26 1571 return need_more;
nuclear@26 1572 }
nuclear@26 1573 if (s->lookahead == 0) break; /* flush the current block */
nuclear@26 1574 }
nuclear@26 1575
nuclear@26 1576 /* Insert the string window[strstart .. strstart+2] in the
nuclear@26 1577 * dictionary, and set hash_head to the head of the hash chain:
nuclear@26 1578 */
nuclear@26 1579 if (s->lookahead >= MIN_MATCH) {
nuclear@26 1580 INSERT_STRING(s, s->strstart, hash_head);
nuclear@26 1581 }
nuclear@26 1582
nuclear@26 1583 /* Find the longest match, discarding those <= prev_length.
nuclear@26 1584 */
nuclear@26 1585 s->prev_length = s->match_length, s->prev_match = s->match_start;
nuclear@26 1586 s->match_length = MIN_MATCH-1;
nuclear@26 1587
nuclear@26 1588 if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
nuclear@26 1589 s->strstart - hash_head <= MAX_DIST(s)) {
nuclear@26 1590 /* To simplify the code, we prevent matches with the string
nuclear@26 1591 * of window index 0 (in particular we have to avoid a match
nuclear@26 1592 * of the string with itself at the start of the input file).
nuclear@26 1593 */
nuclear@26 1594 if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
nuclear@26 1595 s->match_length = longest_match (s, hash_head);
nuclear@26 1596 } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
nuclear@26 1597 s->match_length = longest_match_fast (s, hash_head);
nuclear@26 1598 }
nuclear@26 1599 /* longest_match() or longest_match_fast() sets match_start */
nuclear@26 1600
nuclear@26 1601 if (s->match_length <= 5 && (s->strategy == Z_FILTERED
nuclear@26 1602 #if TOO_FAR <= 32767
nuclear@26 1603 || (s->match_length == MIN_MATCH &&
nuclear@26 1604 s->strstart - s->match_start > TOO_FAR)
nuclear@26 1605 #endif
nuclear@26 1606 )) {
nuclear@26 1607
nuclear@26 1608 /* If prev_match is also MIN_MATCH, match_start is garbage
nuclear@26 1609 * but we will ignore the current match anyway.
nuclear@26 1610 */
nuclear@26 1611 s->match_length = MIN_MATCH-1;
nuclear@26 1612 }
nuclear@26 1613 }
nuclear@26 1614 /* If there was a match at the previous step and the current
nuclear@26 1615 * match is not better, output the previous match:
nuclear@26 1616 */
nuclear@26 1617 if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
nuclear@26 1618 uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
nuclear@26 1619 /* Do not insert strings in hash table beyond this. */
nuclear@26 1620
nuclear@26 1621 check_match(s, s->strstart-1, s->prev_match, s->prev_length);
nuclear@26 1622
nuclear@26 1623 _tr_tally_dist(s, s->strstart -1 - s->prev_match,
nuclear@26 1624 s->prev_length - MIN_MATCH, bflush);
nuclear@26 1625
nuclear@26 1626 /* Insert in hash table all strings up to the end of the match.
nuclear@26 1627 * strstart-1 and strstart are already inserted. If there is not
nuclear@26 1628 * enough lookahead, the last two strings are not inserted in
nuclear@26 1629 * the hash table.
nuclear@26 1630 */
nuclear@26 1631 s->lookahead -= s->prev_length-1;
nuclear@26 1632 s->prev_length -= 2;
nuclear@26 1633 do {
nuclear@26 1634 if (++s->strstart <= max_insert) {
nuclear@26 1635 INSERT_STRING(s, s->strstart, hash_head);
nuclear@26 1636 }
nuclear@26 1637 } while (--s->prev_length != 0);
nuclear@26 1638 s->match_available = 0;
nuclear@26 1639 s->match_length = MIN_MATCH-1;
nuclear@26 1640 s->strstart++;
nuclear@26 1641
nuclear@26 1642 if (bflush) FLUSH_BLOCK(s, 0);
nuclear@26 1643
nuclear@26 1644 } else if (s->match_available) {
nuclear@26 1645 /* If there was no match at the previous position, output a
nuclear@26 1646 * single literal. If there was a match but the current match
nuclear@26 1647 * is longer, truncate the previous match to a single literal.
nuclear@26 1648 */
nuclear@26 1649 Tracevv((stderr,"%c", s->window[s->strstart-1]));
nuclear@26 1650 _tr_tally_lit(s, s->window[s->strstart-1], bflush);
nuclear@26 1651 if (bflush) {
nuclear@26 1652 FLUSH_BLOCK_ONLY(s, 0);
nuclear@26 1653 }
nuclear@26 1654 s->strstart++;
nuclear@26 1655 s->lookahead--;
nuclear@26 1656 if (s->strm->avail_out == 0) return need_more;
nuclear@26 1657 } else {
nuclear@26 1658 /* There is no previous match to compare with, wait for
nuclear@26 1659 * the next step to decide.
nuclear@26 1660 */
nuclear@26 1661 s->match_available = 1;
nuclear@26 1662 s->strstart++;
nuclear@26 1663 s->lookahead--;
nuclear@26 1664 }
nuclear@26 1665 }
nuclear@26 1666 Assert (flush != Z_NO_FLUSH, "no flush?");
nuclear@26 1667 if (s->match_available) {
nuclear@26 1668 Tracevv((stderr,"%c", s->window[s->strstart-1]));
nuclear@26 1669 _tr_tally_lit(s, s->window[s->strstart-1], bflush);
nuclear@26 1670 s->match_available = 0;
nuclear@26 1671 }
nuclear@26 1672 FLUSH_BLOCK(s, flush == Z_FINISH);
nuclear@26 1673 return flush == Z_FINISH ? finish_done : block_done;
nuclear@26 1674 }
nuclear@26 1675 #endif /* FASTEST */
nuclear@26 1676
nuclear@26 1677 #if 0
nuclear@26 1678 /* ===========================================================================
nuclear@26 1679 * For Z_RLE, simply look for runs of bytes, generate matches only of distance
nuclear@26 1680 * one. Do not maintain a hash table. (It will be regenerated if this run of
nuclear@26 1681 * deflate switches away from Z_RLE.)
nuclear@26 1682 */
nuclear@26 1683 local block_state deflate_rle(s, flush)
nuclear@26 1684 deflate_state *s;
nuclear@26 1685 int flush;
nuclear@26 1686 {
nuclear@26 1687 int bflush; /* set if current block must be flushed */
nuclear@26 1688 uInt run; /* length of run */
nuclear@26 1689 uInt max; /* maximum length of run */
nuclear@26 1690 uInt prev; /* byte at distance one to match */
nuclear@26 1691 Bytef *scan; /* scan for end of run */
nuclear@26 1692
nuclear@26 1693 for (;;) {
nuclear@26 1694 /* Make sure that we always have enough lookahead, except
nuclear@26 1695 * at the end of the input file. We need MAX_MATCH bytes
nuclear@26 1696 * for the longest encodable run.
nuclear@26 1697 */
nuclear@26 1698 if (s->lookahead < MAX_MATCH) {
nuclear@26 1699 fill_window(s);
nuclear@26 1700 if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
nuclear@26 1701 return need_more;
nuclear@26 1702 }
nuclear@26 1703 if (s->lookahead == 0) break; /* flush the current block */
nuclear@26 1704 }
nuclear@26 1705
nuclear@26 1706 /* See how many times the previous byte repeats */
nuclear@26 1707 run = 0;
nuclear@26 1708 if (s->strstart > 0) { /* if there is a previous byte, that is */
nuclear@26 1709 max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH;
nuclear@26 1710 scan = s->window + s->strstart - 1;
nuclear@26 1711 prev = *scan++;
nuclear@26 1712 do {
nuclear@26 1713 if (*scan++ != prev)
nuclear@26 1714 break;
nuclear@26 1715 } while (++run < max);
nuclear@26 1716 }
nuclear@26 1717
nuclear@26 1718 /* Emit match if have run of MIN_MATCH or longer, else emit literal */
nuclear@26 1719 if (run >= MIN_MATCH) {
nuclear@26 1720 check_match(s, s->strstart, s->strstart - 1, run);
nuclear@26 1721 _tr_tally_dist(s, 1, run - MIN_MATCH, bflush);
nuclear@26 1722 s->lookahead -= run;
nuclear@26 1723 s->strstart += run;
nuclear@26 1724 } else {
nuclear@26 1725 /* No match, output a literal byte */
nuclear@26 1726 Tracevv((stderr,"%c", s->window[s->strstart]));
nuclear@26 1727 _tr_tally_lit (s, s->window[s->strstart], bflush);
nuclear@26 1728 s->lookahead--;
nuclear@26 1729 s->strstart++;
nuclear@26 1730 }
nuclear@26 1731 if (bflush) FLUSH_BLOCK(s, 0);
nuclear@26 1732 }
nuclear@26 1733 FLUSH_BLOCK(s, flush == Z_FINISH);
nuclear@26 1734 return flush == Z_FINISH ? finish_done : block_done;
nuclear@26 1735 }
nuclear@26 1736 #endif