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annotate libs/zlib/deflate.c @ 20:2b85d05df3f2

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author John Tsiombikas <nuclear@member.fsf.org>
date Fri, 02 Oct 2015 04:54:55 +0300
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nuclear@2 1 /* deflate.c -- compress data using the deflation algorithm
nuclear@2 2 * Copyright (C) 1995-2005 Jean-loup Gailly.
nuclear@2 3 * For conditions of distribution and use, see copyright notice in zlib.h
nuclear@2 4 */
nuclear@2 5
nuclear@2 6 /*
nuclear@2 7 * ALGORITHM
nuclear@2 8 *
nuclear@2 9 * The "deflation" process depends on being able to identify portions
nuclear@2 10 * of the input text which are identical to earlier input (within a
nuclear@2 11 * sliding window trailing behind the input currently being processed).
nuclear@2 12 *
nuclear@2 13 * The most straightforward technique turns out to be the fastest for
nuclear@2 14 * most input files: try all possible matches and select the longest.
nuclear@2 15 * The key feature of this algorithm is that insertions into the string
nuclear@2 16 * dictionary are very simple and thus fast, and deletions are avoided
nuclear@2 17 * completely. Insertions are performed at each input character, whereas
nuclear@2 18 * string matches are performed only when the previous match ends. So it
nuclear@2 19 * is preferable to spend more time in matches to allow very fast string
nuclear@2 20 * insertions and avoid deletions. The matching algorithm for small
nuclear@2 21 * strings is inspired from that of Rabin & Karp. A brute force approach
nuclear@2 22 * is used to find longer strings when a small match has been found.
nuclear@2 23 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
nuclear@2 24 * (by Leonid Broukhis).
nuclear@2 25 * A previous version of this file used a more sophisticated algorithm
nuclear@2 26 * (by Fiala and Greene) which is guaranteed to run in linear amortized
nuclear@2 27 * time, but has a larger average cost, uses more memory and is patented.
nuclear@2 28 * However the F&G algorithm may be faster for some highly redundant
nuclear@2 29 * files if the parameter max_chain_length (described below) is too large.
nuclear@2 30 *
nuclear@2 31 * ACKNOWLEDGEMENTS
nuclear@2 32 *
nuclear@2 33 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
nuclear@2 34 * I found it in 'freeze' written by Leonid Broukhis.
nuclear@2 35 * Thanks to many people for bug reports and testing.
nuclear@2 36 *
nuclear@2 37 * REFERENCES
nuclear@2 38 *
nuclear@2 39 * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
nuclear@2 40 * Available in http://www.ietf.org/rfc/rfc1951.txt
nuclear@2 41 *
nuclear@2 42 * A description of the Rabin and Karp algorithm is given in the book
nuclear@2 43 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
nuclear@2 44 *
nuclear@2 45 * Fiala,E.R., and Greene,D.H.
nuclear@2 46 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
nuclear@2 47 *
nuclear@2 48 */
nuclear@2 49
nuclear@2 50 /* @(#) $Id$ */
nuclear@2 51
nuclear@2 52 #include "deflate.h"
nuclear@2 53
nuclear@2 54 const char deflate_copyright[] =
nuclear@2 55 " deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly ";
nuclear@2 56 /*
nuclear@2 57 If you use the zlib library in a product, an acknowledgment is welcome
nuclear@2 58 in the documentation of your product. If for some reason you cannot
nuclear@2 59 include such an acknowledgment, I would appreciate that you keep this
nuclear@2 60 copyright string in the executable of your product.
nuclear@2 61 */
nuclear@2 62
nuclear@2 63 /* ===========================================================================
nuclear@2 64 * Function prototypes.
nuclear@2 65 */
nuclear@2 66 typedef enum {
nuclear@2 67 need_more, /* block not completed, need more input or more output */
nuclear@2 68 block_done, /* block flush performed */
nuclear@2 69 finish_started, /* finish started, need only more output at next deflate */
nuclear@2 70 finish_done /* finish done, accept no more input or output */
nuclear@2 71 } block_state;
nuclear@2 72
nuclear@2 73 typedef block_state (*compress_func) OF((deflate_state *s, int flush));
nuclear@2 74 /* Compression function. Returns the block state after the call. */
nuclear@2 75
nuclear@2 76 local void fill_window OF((deflate_state *s));
nuclear@2 77 local block_state deflate_stored OF((deflate_state *s, int flush));
nuclear@2 78 local block_state deflate_fast OF((deflate_state *s, int flush));
nuclear@2 79 #ifndef FASTEST
nuclear@2 80 local block_state deflate_slow OF((deflate_state *s, int flush));
nuclear@2 81 #endif
nuclear@2 82 local void lm_init OF((deflate_state *s));
nuclear@2 83 local void putShortMSB OF((deflate_state *s, uInt b));
nuclear@2 84 local void flush_pending OF((z_streamp strm));
nuclear@2 85 local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
nuclear@2 86 #ifndef FASTEST
nuclear@2 87 #ifdef ASMV
nuclear@2 88 void match_init OF((void)); /* asm code initialization */
nuclear@2 89 uInt longest_match OF((deflate_state *s, IPos cur_match));
nuclear@2 90 #else
nuclear@2 91 local uInt longest_match OF((deflate_state *s, IPos cur_match));
nuclear@2 92 #endif
nuclear@2 93 #endif
nuclear@2 94 local uInt longest_match_fast OF((deflate_state *s, IPos cur_match));
nuclear@2 95
nuclear@2 96 #ifdef DEBUG
nuclear@2 97 local void check_match OF((deflate_state *s, IPos start, IPos match,
nuclear@2 98 int length));
nuclear@2 99 #endif
nuclear@2 100
nuclear@2 101 /* ===========================================================================
nuclear@2 102 * Local data
nuclear@2 103 */
nuclear@2 104
nuclear@2 105 #define NIL 0
nuclear@2 106 /* Tail of hash chains */
nuclear@2 107
nuclear@2 108 #ifndef TOO_FAR
nuclear@2 109 # define TOO_FAR 4096
nuclear@2 110 #endif
nuclear@2 111 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
nuclear@2 112
nuclear@2 113 #define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
nuclear@2 114 /* Minimum amount of lookahead, except at the end of the input file.
nuclear@2 115 * See deflate.c for comments about the MIN_MATCH+1.
nuclear@2 116 */
nuclear@2 117
nuclear@2 118 /* Values for max_lazy_match, good_match and max_chain_length, depending on
nuclear@2 119 * the desired pack level (0..9). The values given below have been tuned to
nuclear@2 120 * exclude worst case performance for pathological files. Better values may be
nuclear@2 121 * found for specific files.
nuclear@2 122 */
nuclear@2 123 typedef struct config_s {
nuclear@2 124 ush good_length; /* reduce lazy search above this match length */
nuclear@2 125 ush max_lazy; /* do not perform lazy search above this match length */
nuclear@2 126 ush nice_length; /* quit search above this match length */
nuclear@2 127 ush max_chain;
nuclear@2 128 compress_func func;
nuclear@2 129 } config;
nuclear@2 130
nuclear@2 131 #ifdef FASTEST
nuclear@2 132 local const config configuration_table[2] = {
nuclear@2 133 /* good lazy nice chain */
nuclear@2 134 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
nuclear@2 135 /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
nuclear@2 136 #else
nuclear@2 137 local const config configuration_table[10] = {
nuclear@2 138 /* good lazy nice chain */
nuclear@2 139 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
nuclear@2 140 /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
nuclear@2 141 /* 2 */ {4, 5, 16, 8, deflate_fast},
nuclear@2 142 /* 3 */ {4, 6, 32, 32, deflate_fast},
nuclear@2 143
nuclear@2 144 /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
nuclear@2 145 /* 5 */ {8, 16, 32, 32, deflate_slow},
nuclear@2 146 /* 6 */ {8, 16, 128, 128, deflate_slow},
nuclear@2 147 /* 7 */ {8, 32, 128, 256, deflate_slow},
nuclear@2 148 /* 8 */ {32, 128, 258, 1024, deflate_slow},
nuclear@2 149 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
nuclear@2 150 #endif
nuclear@2 151
nuclear@2 152 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
nuclear@2 153 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
nuclear@2 154 * meaning.
nuclear@2 155 */
nuclear@2 156
nuclear@2 157 #define EQUAL 0
nuclear@2 158 /* result of memcmp for equal strings */
nuclear@2 159
nuclear@2 160 #ifndef NO_DUMMY_DECL
nuclear@2 161 struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
nuclear@2 162 #endif
nuclear@2 163
nuclear@2 164 /* ===========================================================================
nuclear@2 165 * Update a hash value with the given input byte
nuclear@2 166 * IN assertion: all calls to to UPDATE_HASH are made with consecutive
nuclear@2 167 * input characters, so that a running hash key can be computed from the
nuclear@2 168 * previous key instead of complete recalculation each time.
nuclear@2 169 */
nuclear@2 170 #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
nuclear@2 171
nuclear@2 172
nuclear@2 173 /* ===========================================================================
nuclear@2 174 * Insert string str in the dictionary and set match_head to the previous head
nuclear@2 175 * of the hash chain (the most recent string with same hash key). Return
nuclear@2 176 * the previous length of the hash chain.
nuclear@2 177 * If this file is compiled with -DFASTEST, the compression level is forced
nuclear@2 178 * to 1, and no hash chains are maintained.
nuclear@2 179 * IN assertion: all calls to to INSERT_STRING are made with consecutive
nuclear@2 180 * input characters and the first MIN_MATCH bytes of str are valid
nuclear@2 181 * (except for the last MIN_MATCH-1 bytes of the input file).
nuclear@2 182 */
nuclear@2 183 #ifdef FASTEST
nuclear@2 184 #define INSERT_STRING(s, str, match_head) \
nuclear@2 185 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
nuclear@2 186 match_head = s->head[s->ins_h], \
nuclear@2 187 s->head[s->ins_h] = (Pos)(str))
nuclear@2 188 #else
nuclear@2 189 #define INSERT_STRING(s, str, match_head) \
nuclear@2 190 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
nuclear@2 191 match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
nuclear@2 192 s->head[s->ins_h] = (Pos)(str))
nuclear@2 193 #endif
nuclear@2 194
nuclear@2 195 /* ===========================================================================
nuclear@2 196 * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
nuclear@2 197 * prev[] will be initialized on the fly.
nuclear@2 198 */
nuclear@2 199 #define CLEAR_HASH(s) \
nuclear@2 200 s->head[s->hash_size-1] = NIL; \
nuclear@2 201 zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
nuclear@2 202
nuclear@2 203 /* ========================================================================= */
nuclear@2 204 int ZEXPORT deflateInit_(strm, level, version, stream_size)
nuclear@2 205 z_streamp strm;
nuclear@2 206 int level;
nuclear@2 207 const char *version;
nuclear@2 208 int stream_size;
nuclear@2 209 {
nuclear@2 210 return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
nuclear@2 211 Z_DEFAULT_STRATEGY, version, stream_size);
nuclear@2 212 /* To do: ignore strm->next_in if we use it as window */
nuclear@2 213 }
nuclear@2 214
nuclear@2 215 /* ========================================================================= */
nuclear@2 216 int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
nuclear@2 217 version, stream_size)
nuclear@2 218 z_streamp strm;
nuclear@2 219 int level;
nuclear@2 220 int method;
nuclear@2 221 int windowBits;
nuclear@2 222 int memLevel;
nuclear@2 223 int strategy;
nuclear@2 224 const char *version;
nuclear@2 225 int stream_size;
nuclear@2 226 {
nuclear@2 227 deflate_state *s;
nuclear@2 228 int wrap = 1;
nuclear@2 229 static const char my_version[] = ZLIB_VERSION;
nuclear@2 230
nuclear@2 231 ushf *overlay;
nuclear@2 232 /* We overlay pending_buf and d_buf+l_buf. This works since the average
nuclear@2 233 * output size for (length,distance) codes is <= 24 bits.
nuclear@2 234 */
nuclear@2 235
nuclear@2 236 if (version == Z_NULL || version[0] != my_version[0] ||
nuclear@2 237 stream_size != sizeof(z_stream)) {
nuclear@2 238 return Z_VERSION_ERROR;
nuclear@2 239 }
nuclear@2 240 if (strm == Z_NULL) return Z_STREAM_ERROR;
nuclear@2 241
nuclear@2 242 strm->msg = Z_NULL;
nuclear@2 243 if (strm->zalloc == (alloc_func)0) {
nuclear@2 244 strm->zalloc = zcalloc;
nuclear@2 245 strm->opaque = (voidpf)0;
nuclear@2 246 }
nuclear@2 247 if (strm->zfree == (free_func)0) strm->zfree = zcfree;
nuclear@2 248
nuclear@2 249 #ifdef FASTEST
nuclear@2 250 if (level != 0) level = 1;
nuclear@2 251 #else
nuclear@2 252 if (level == Z_DEFAULT_COMPRESSION) level = 6;
nuclear@2 253 #endif
nuclear@2 254
nuclear@2 255 if (windowBits < 0) { /* suppress zlib wrapper */
nuclear@2 256 wrap = 0;
nuclear@2 257 windowBits = -windowBits;
nuclear@2 258 }
nuclear@2 259 #ifdef GZIP
nuclear@2 260 else if (windowBits > 15) {
nuclear@2 261 wrap = 2; /* write gzip wrapper instead */
nuclear@2 262 windowBits -= 16;
nuclear@2 263 }
nuclear@2 264 #endif
nuclear@2 265 if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
nuclear@2 266 windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
nuclear@2 267 strategy < 0 || strategy > Z_FIXED) {
nuclear@2 268 return Z_STREAM_ERROR;
nuclear@2 269 }
nuclear@2 270 if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
nuclear@2 271 s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
nuclear@2 272 if (s == Z_NULL) return Z_MEM_ERROR;
nuclear@2 273 strm->state = (struct internal_state FAR *)s;
nuclear@2 274 s->strm = strm;
nuclear@2 275
nuclear@2 276 s->wrap = wrap;
nuclear@2 277 s->gzhead = Z_NULL;
nuclear@2 278 s->w_bits = windowBits;
nuclear@2 279 s->w_size = 1 << s->w_bits;
nuclear@2 280 s->w_mask = s->w_size - 1;
nuclear@2 281
nuclear@2 282 s->hash_bits = memLevel + 7;
nuclear@2 283 s->hash_size = 1 << s->hash_bits;
nuclear@2 284 s->hash_mask = s->hash_size - 1;
nuclear@2 285 s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
nuclear@2 286
nuclear@2 287 s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
nuclear@2 288 s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
nuclear@2 289 s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
nuclear@2 290
nuclear@2 291 s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
nuclear@2 292
nuclear@2 293 overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
nuclear@2 294 s->pending_buf = (uchf *) overlay;
nuclear@2 295 s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
nuclear@2 296
nuclear@2 297 if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
nuclear@2 298 s->pending_buf == Z_NULL) {
nuclear@2 299 s->status = FINISH_STATE;
nuclear@2 300 strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
nuclear@2 301 deflateEnd (strm);
nuclear@2 302 return Z_MEM_ERROR;
nuclear@2 303 }
nuclear@2 304 s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
nuclear@2 305 s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
nuclear@2 306
nuclear@2 307 s->level = level;
nuclear@2 308 s->strategy = strategy;
nuclear@2 309 s->method = (Byte)method;
nuclear@2 310
nuclear@2 311 return deflateReset(strm);
nuclear@2 312 }
nuclear@2 313
nuclear@2 314 /* ========================================================================= */
nuclear@2 315 int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
nuclear@2 316 z_streamp strm;
nuclear@2 317 const Bytef *dictionary;
nuclear@2 318 uInt dictLength;
nuclear@2 319 {
nuclear@2 320 deflate_state *s;
nuclear@2 321 uInt length = dictLength;
nuclear@2 322 uInt n;
nuclear@2 323 IPos hash_head = 0;
nuclear@2 324
nuclear@2 325 if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
nuclear@2 326 strm->state->wrap == 2 ||
nuclear@2 327 (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
nuclear@2 328 return Z_STREAM_ERROR;
nuclear@2 329
nuclear@2 330 s = strm->state;
nuclear@2 331 if (s->wrap)
nuclear@2 332 strm->adler = adler32(strm->adler, dictionary, dictLength);
nuclear@2 333
nuclear@2 334 if (length < MIN_MATCH) return Z_OK;
nuclear@2 335 if (length > MAX_DIST(s)) {
nuclear@2 336 length = MAX_DIST(s);
nuclear@2 337 dictionary += dictLength - length; /* use the tail of the dictionary */
nuclear@2 338 }
nuclear@2 339 zmemcpy(s->window, dictionary, length);
nuclear@2 340 s->strstart = length;
nuclear@2 341 s->block_start = (long)length;
nuclear@2 342
nuclear@2 343 /* Insert all strings in the hash table (except for the last two bytes).
nuclear@2 344 * s->lookahead stays null, so s->ins_h will be recomputed at the next
nuclear@2 345 * call of fill_window.
nuclear@2 346 */
nuclear@2 347 s->ins_h = s->window[0];
nuclear@2 348 UPDATE_HASH(s, s->ins_h, s->window[1]);
nuclear@2 349 for (n = 0; n <= length - MIN_MATCH; n++) {
nuclear@2 350 INSERT_STRING(s, n, hash_head);
nuclear@2 351 }
nuclear@2 352 if (hash_head) hash_head = 0; /* to make compiler happy */
nuclear@2 353 return Z_OK;
nuclear@2 354 }
nuclear@2 355
nuclear@2 356 /* ========================================================================= */
nuclear@2 357 int ZEXPORT deflateReset (strm)
nuclear@2 358 z_streamp strm;
nuclear@2 359 {
nuclear@2 360 deflate_state *s;
nuclear@2 361
nuclear@2 362 if (strm == Z_NULL || strm->state == Z_NULL ||
nuclear@2 363 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
nuclear@2 364 return Z_STREAM_ERROR;
nuclear@2 365 }
nuclear@2 366
nuclear@2 367 strm->total_in = strm->total_out = 0;
nuclear@2 368 strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
nuclear@2 369 strm->data_type = Z_UNKNOWN;
nuclear@2 370
nuclear@2 371 s = (deflate_state *)strm->state;
nuclear@2 372 s->pending = 0;
nuclear@2 373 s->pending_out = s->pending_buf;
nuclear@2 374
nuclear@2 375 if (s->wrap < 0) {
nuclear@2 376 s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
nuclear@2 377 }
nuclear@2 378 s->status = s->wrap ? INIT_STATE : BUSY_STATE;
nuclear@2 379 strm->adler =
nuclear@2 380 #ifdef GZIP
nuclear@2 381 s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
nuclear@2 382 #endif
nuclear@2 383 adler32(0L, Z_NULL, 0);
nuclear@2 384 s->last_flush = Z_NO_FLUSH;
nuclear@2 385
nuclear@2 386 _tr_init(s);
nuclear@2 387 lm_init(s);
nuclear@2 388
nuclear@2 389 return Z_OK;
nuclear@2 390 }
nuclear@2 391
nuclear@2 392 /* ========================================================================= */
nuclear@2 393 int ZEXPORT deflateSetHeader (strm, head)
nuclear@2 394 z_streamp strm;
nuclear@2 395 gz_headerp head;
nuclear@2 396 {
nuclear@2 397 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@2 398 if (strm->state->wrap != 2) return Z_STREAM_ERROR;
nuclear@2 399 strm->state->gzhead = head;
nuclear@2 400 return Z_OK;
nuclear@2 401 }
nuclear@2 402
nuclear@2 403 /* ========================================================================= */
nuclear@2 404 int ZEXPORT deflatePrime (strm, bits, value)
nuclear@2 405 z_streamp strm;
nuclear@2 406 int bits;
nuclear@2 407 int value;
nuclear@2 408 {
nuclear@2 409 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@2 410 strm->state->bi_valid = bits;
nuclear@2 411 strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
nuclear@2 412 return Z_OK;
nuclear@2 413 }
nuclear@2 414
nuclear@2 415 /* ========================================================================= */
nuclear@2 416 int ZEXPORT deflateParams(strm, level, strategy)
nuclear@2 417 z_streamp strm;
nuclear@2 418 int level;
nuclear@2 419 int strategy;
nuclear@2 420 {
nuclear@2 421 deflate_state *s;
nuclear@2 422 compress_func func;
nuclear@2 423 int err = Z_OK;
nuclear@2 424
nuclear@2 425 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@2 426 s = strm->state;
nuclear@2 427
nuclear@2 428 #ifdef FASTEST
nuclear@2 429 if (level != 0) level = 1;
nuclear@2 430 #else
nuclear@2 431 if (level == Z_DEFAULT_COMPRESSION) level = 6;
nuclear@2 432 #endif
nuclear@2 433 if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
nuclear@2 434 return Z_STREAM_ERROR;
nuclear@2 435 }
nuclear@2 436 func = configuration_table[s->level].func;
nuclear@2 437
nuclear@2 438 if (func != configuration_table[level].func && strm->total_in != 0) {
nuclear@2 439 /* Flush the last buffer: */
nuclear@2 440 err = deflate(strm, Z_PARTIAL_FLUSH);
nuclear@2 441 }
nuclear@2 442 if (s->level != level) {
nuclear@2 443 s->level = level;
nuclear@2 444 s->max_lazy_match = configuration_table[level].max_lazy;
nuclear@2 445 s->good_match = configuration_table[level].good_length;
nuclear@2 446 s->nice_match = configuration_table[level].nice_length;
nuclear@2 447 s->max_chain_length = configuration_table[level].max_chain;
nuclear@2 448 }
nuclear@2 449 s->strategy = strategy;
nuclear@2 450 return err;
nuclear@2 451 }
nuclear@2 452
nuclear@2 453 /* ========================================================================= */
nuclear@2 454 int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
nuclear@2 455 z_streamp strm;
nuclear@2 456 int good_length;
nuclear@2 457 int max_lazy;
nuclear@2 458 int nice_length;
nuclear@2 459 int max_chain;
nuclear@2 460 {
nuclear@2 461 deflate_state *s;
nuclear@2 462
nuclear@2 463 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@2 464 s = strm->state;
nuclear@2 465 s->good_match = good_length;
nuclear@2 466 s->max_lazy_match = max_lazy;
nuclear@2 467 s->nice_match = nice_length;
nuclear@2 468 s->max_chain_length = max_chain;
nuclear@2 469 return Z_OK;
nuclear@2 470 }
nuclear@2 471
nuclear@2 472 /* =========================================================================
nuclear@2 473 * For the default windowBits of 15 and memLevel of 8, this function returns
nuclear@2 474 * a close to exact, as well as small, upper bound on the compressed size.
nuclear@2 475 * They are coded as constants here for a reason--if the #define's are
nuclear@2 476 * changed, then this function needs to be changed as well. The return
nuclear@2 477 * value for 15 and 8 only works for those exact settings.
nuclear@2 478 *
nuclear@2 479 * For any setting other than those defaults for windowBits and memLevel,
nuclear@2 480 * the value returned is a conservative worst case for the maximum expansion
nuclear@2 481 * resulting from using fixed blocks instead of stored blocks, which deflate
nuclear@2 482 * can emit on compressed data for some combinations of the parameters.
nuclear@2 483 *
nuclear@2 484 * This function could be more sophisticated to provide closer upper bounds
nuclear@2 485 * for every combination of windowBits and memLevel, as well as wrap.
nuclear@2 486 * But even the conservative upper bound of about 14% expansion does not
nuclear@2 487 * seem onerous for output buffer allocation.
nuclear@2 488 */
nuclear@2 489 uLong ZEXPORT deflateBound(strm, sourceLen)
nuclear@2 490 z_streamp strm;
nuclear@2 491 uLong sourceLen;
nuclear@2 492 {
nuclear@2 493 deflate_state *s;
nuclear@2 494 uLong destLen;
nuclear@2 495
nuclear@2 496 /* conservative upper bound */
nuclear@2 497 destLen = sourceLen +
nuclear@2 498 ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
nuclear@2 499
nuclear@2 500 /* if can't get parameters, return conservative bound */
nuclear@2 501 if (strm == Z_NULL || strm->state == Z_NULL)
nuclear@2 502 return destLen;
nuclear@2 503
nuclear@2 504 /* if not default parameters, return conservative bound */
nuclear@2 505 s = strm->state;
nuclear@2 506 if (s->w_bits != 15 || s->hash_bits != 8 + 7)
nuclear@2 507 return destLen;
nuclear@2 508
nuclear@2 509 /* default settings: return tight bound for that case */
nuclear@2 510 return compressBound(sourceLen);
nuclear@2 511 }
nuclear@2 512
nuclear@2 513 /* =========================================================================
nuclear@2 514 * Put a short in the pending buffer. The 16-bit value is put in MSB order.
nuclear@2 515 * IN assertion: the stream state is correct and there is enough room in
nuclear@2 516 * pending_buf.
nuclear@2 517 */
nuclear@2 518 local void putShortMSB (s, b)
nuclear@2 519 deflate_state *s;
nuclear@2 520 uInt b;
nuclear@2 521 {
nuclear@2 522 put_byte(s, (Byte)(b >> 8));
nuclear@2 523 put_byte(s, (Byte)(b & 0xff));
nuclear@2 524 }
nuclear@2 525
nuclear@2 526 /* =========================================================================
nuclear@2 527 * Flush as much pending output as possible. All deflate() output goes
nuclear@2 528 * through this function so some applications may wish to modify it
nuclear@2 529 * to avoid allocating a large strm->next_out buffer and copying into it.
nuclear@2 530 * (See also read_buf()).
nuclear@2 531 */
nuclear@2 532 local void flush_pending(strm)
nuclear@2 533 z_streamp strm;
nuclear@2 534 {
nuclear@2 535 unsigned len = strm->state->pending;
nuclear@2 536
nuclear@2 537 if (len > strm->avail_out) len = strm->avail_out;
nuclear@2 538 if (len == 0) return;
nuclear@2 539
nuclear@2 540 zmemcpy(strm->next_out, strm->state->pending_out, len);
nuclear@2 541 strm->next_out += len;
nuclear@2 542 strm->state->pending_out += len;
nuclear@2 543 strm->total_out += len;
nuclear@2 544 strm->avail_out -= len;
nuclear@2 545 strm->state->pending -= len;
nuclear@2 546 if (strm->state->pending == 0) {
nuclear@2 547 strm->state->pending_out = strm->state->pending_buf;
nuclear@2 548 }
nuclear@2 549 }
nuclear@2 550
nuclear@2 551 /* ========================================================================= */
nuclear@2 552 int ZEXPORT deflate (strm, flush)
nuclear@2 553 z_streamp strm;
nuclear@2 554 int flush;
nuclear@2 555 {
nuclear@2 556 int old_flush; /* value of flush param for previous deflate call */
nuclear@2 557 deflate_state *s;
nuclear@2 558
nuclear@2 559 if (strm == Z_NULL || strm->state == Z_NULL ||
nuclear@2 560 flush > Z_FINISH || flush < 0) {
nuclear@2 561 return Z_STREAM_ERROR;
nuclear@2 562 }
nuclear@2 563 s = strm->state;
nuclear@2 564
nuclear@2 565 if (strm->next_out == Z_NULL ||
nuclear@2 566 (strm->next_in == Z_NULL && strm->avail_in != 0) ||
nuclear@2 567 (s->status == FINISH_STATE && flush != Z_FINISH)) {
nuclear@2 568 ERR_RETURN(strm, Z_STREAM_ERROR);
nuclear@2 569 }
nuclear@2 570 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
nuclear@2 571
nuclear@2 572 s->strm = strm; /* just in case */
nuclear@2 573 old_flush = s->last_flush;
nuclear@2 574 s->last_flush = flush;
nuclear@2 575
nuclear@2 576 /* Write the header */
nuclear@2 577 if (s->status == INIT_STATE) {
nuclear@2 578 #ifdef GZIP
nuclear@2 579 if (s->wrap == 2) {
nuclear@2 580 strm->adler = crc32(0L, Z_NULL, 0);
nuclear@2 581 put_byte(s, 31);
nuclear@2 582 put_byte(s, 139);
nuclear@2 583 put_byte(s, 8);
nuclear@2 584 if (s->gzhead == NULL) {
nuclear@2 585 put_byte(s, 0);
nuclear@2 586 put_byte(s, 0);
nuclear@2 587 put_byte(s, 0);
nuclear@2 588 put_byte(s, 0);
nuclear@2 589 put_byte(s, 0);
nuclear@2 590 put_byte(s, s->level == 9 ? 2 :
nuclear@2 591 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
nuclear@2 592 4 : 0));
nuclear@2 593 put_byte(s, OS_CODE);
nuclear@2 594 s->status = BUSY_STATE;
nuclear@2 595 }
nuclear@2 596 else {
nuclear@2 597 put_byte(s, (s->gzhead->text ? 1 : 0) +
nuclear@2 598 (s->gzhead->hcrc ? 2 : 0) +
nuclear@2 599 (s->gzhead->extra == Z_NULL ? 0 : 4) +
nuclear@2 600 (s->gzhead->name == Z_NULL ? 0 : 8) +
nuclear@2 601 (s->gzhead->comment == Z_NULL ? 0 : 16)
nuclear@2 602 );
nuclear@2 603 put_byte(s, (Byte)(s->gzhead->time & 0xff));
nuclear@2 604 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
nuclear@2 605 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
nuclear@2 606 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
nuclear@2 607 put_byte(s, s->level == 9 ? 2 :
nuclear@2 608 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
nuclear@2 609 4 : 0));
nuclear@2 610 put_byte(s, s->gzhead->os & 0xff);
nuclear@2 611 if (s->gzhead->extra != NULL) {
nuclear@2 612 put_byte(s, s->gzhead->extra_len & 0xff);
nuclear@2 613 put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
nuclear@2 614 }
nuclear@2 615 if (s->gzhead->hcrc)
nuclear@2 616 strm->adler = crc32(strm->adler, s->pending_buf,
nuclear@2 617 s->pending);
nuclear@2 618 s->gzindex = 0;
nuclear@2 619 s->status = EXTRA_STATE;
nuclear@2 620 }
nuclear@2 621 }
nuclear@2 622 else
nuclear@2 623 #endif
nuclear@2 624 {
nuclear@2 625 uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
nuclear@2 626 uInt level_flags;
nuclear@2 627
nuclear@2 628 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
nuclear@2 629 level_flags = 0;
nuclear@2 630 else if (s->level < 6)
nuclear@2 631 level_flags = 1;
nuclear@2 632 else if (s->level == 6)
nuclear@2 633 level_flags = 2;
nuclear@2 634 else
nuclear@2 635 level_flags = 3;
nuclear@2 636 header |= (level_flags << 6);
nuclear@2 637 if (s->strstart != 0) header |= PRESET_DICT;
nuclear@2 638 header += 31 - (header % 31);
nuclear@2 639
nuclear@2 640 s->status = BUSY_STATE;
nuclear@2 641 putShortMSB(s, header);
nuclear@2 642
nuclear@2 643 /* Save the adler32 of the preset dictionary: */
nuclear@2 644 if (s->strstart != 0) {
nuclear@2 645 putShortMSB(s, (uInt)(strm->adler >> 16));
nuclear@2 646 putShortMSB(s, (uInt)(strm->adler & 0xffff));
nuclear@2 647 }
nuclear@2 648 strm->adler = adler32(0L, Z_NULL, 0);
nuclear@2 649 }
nuclear@2 650 }
nuclear@2 651 #ifdef GZIP
nuclear@2 652 if (s->status == EXTRA_STATE) {
nuclear@2 653 if (s->gzhead->extra != NULL) {
nuclear@2 654 uInt beg = s->pending; /* start of bytes to update crc */
nuclear@2 655
nuclear@2 656 while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
nuclear@2 657 if (s->pending == s->pending_buf_size) {
nuclear@2 658 if (s->gzhead->hcrc && s->pending > beg)
nuclear@2 659 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@2 660 s->pending - beg);
nuclear@2 661 flush_pending(strm);
nuclear@2 662 beg = s->pending;
nuclear@2 663 if (s->pending == s->pending_buf_size)
nuclear@2 664 break;
nuclear@2 665 }
nuclear@2 666 put_byte(s, s->gzhead->extra[s->gzindex]);
nuclear@2 667 s->gzindex++;
nuclear@2 668 }
nuclear@2 669 if (s->gzhead->hcrc && s->pending > beg)
nuclear@2 670 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@2 671 s->pending - beg);
nuclear@2 672 if (s->gzindex == s->gzhead->extra_len) {
nuclear@2 673 s->gzindex = 0;
nuclear@2 674 s->status = NAME_STATE;
nuclear@2 675 }
nuclear@2 676 }
nuclear@2 677 else
nuclear@2 678 s->status = NAME_STATE;
nuclear@2 679 }
nuclear@2 680 if (s->status == NAME_STATE) {
nuclear@2 681 if (s->gzhead->name != NULL) {
nuclear@2 682 uInt beg = s->pending; /* start of bytes to update crc */
nuclear@2 683 int val;
nuclear@2 684
nuclear@2 685 do {
nuclear@2 686 if (s->pending == s->pending_buf_size) {
nuclear@2 687 if (s->gzhead->hcrc && s->pending > beg)
nuclear@2 688 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@2 689 s->pending - beg);
nuclear@2 690 flush_pending(strm);
nuclear@2 691 beg = s->pending;
nuclear@2 692 if (s->pending == s->pending_buf_size) {
nuclear@2 693 val = 1;
nuclear@2 694 break;
nuclear@2 695 }
nuclear@2 696 }
nuclear@2 697 val = s->gzhead->name[s->gzindex++];
nuclear@2 698 put_byte(s, val);
nuclear@2 699 } while (val != 0);
nuclear@2 700 if (s->gzhead->hcrc && s->pending > beg)
nuclear@2 701 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@2 702 s->pending - beg);
nuclear@2 703 if (val == 0) {
nuclear@2 704 s->gzindex = 0;
nuclear@2 705 s->status = COMMENT_STATE;
nuclear@2 706 }
nuclear@2 707 }
nuclear@2 708 else
nuclear@2 709 s->status = COMMENT_STATE;
nuclear@2 710 }
nuclear@2 711 if (s->status == COMMENT_STATE) {
nuclear@2 712 if (s->gzhead->comment != NULL) {
nuclear@2 713 uInt beg = s->pending; /* start of bytes to update crc */
nuclear@2 714 int val;
nuclear@2 715
nuclear@2 716 do {
nuclear@2 717 if (s->pending == s->pending_buf_size) {
nuclear@2 718 if (s->gzhead->hcrc && s->pending > beg)
nuclear@2 719 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@2 720 s->pending - beg);
nuclear@2 721 flush_pending(strm);
nuclear@2 722 beg = s->pending;
nuclear@2 723 if (s->pending == s->pending_buf_size) {
nuclear@2 724 val = 1;
nuclear@2 725 break;
nuclear@2 726 }
nuclear@2 727 }
nuclear@2 728 val = s->gzhead->comment[s->gzindex++];
nuclear@2 729 put_byte(s, val);
nuclear@2 730 } while (val != 0);
nuclear@2 731 if (s->gzhead->hcrc && s->pending > beg)
nuclear@2 732 strm->adler = crc32(strm->adler, s->pending_buf + beg,
nuclear@2 733 s->pending - beg);
nuclear@2 734 if (val == 0)
nuclear@2 735 s->status = HCRC_STATE;
nuclear@2 736 }
nuclear@2 737 else
nuclear@2 738 s->status = HCRC_STATE;
nuclear@2 739 }
nuclear@2 740 if (s->status == HCRC_STATE) {
nuclear@2 741 if (s->gzhead->hcrc) {
nuclear@2 742 if (s->pending + 2 > s->pending_buf_size)
nuclear@2 743 flush_pending(strm);
nuclear@2 744 if (s->pending + 2 <= s->pending_buf_size) {
nuclear@2 745 put_byte(s, (Byte)(strm->adler & 0xff));
nuclear@2 746 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
nuclear@2 747 strm->adler = crc32(0L, Z_NULL, 0);
nuclear@2 748 s->status = BUSY_STATE;
nuclear@2 749 }
nuclear@2 750 }
nuclear@2 751 else
nuclear@2 752 s->status = BUSY_STATE;
nuclear@2 753 }
nuclear@2 754 #endif
nuclear@2 755
nuclear@2 756 /* Flush as much pending output as possible */
nuclear@2 757 if (s->pending != 0) {
nuclear@2 758 flush_pending(strm);
nuclear@2 759 if (strm->avail_out == 0) {
nuclear@2 760 /* Since avail_out is 0, deflate will be called again with
nuclear@2 761 * more output space, but possibly with both pending and
nuclear@2 762 * avail_in equal to zero. There won't be anything to do,
nuclear@2 763 * but this is not an error situation so make sure we
nuclear@2 764 * return OK instead of BUF_ERROR at next call of deflate:
nuclear@2 765 */
nuclear@2 766 s->last_flush = -1;
nuclear@2 767 return Z_OK;
nuclear@2 768 }
nuclear@2 769
nuclear@2 770 /* Make sure there is something to do and avoid duplicate consecutive
nuclear@2 771 * flushes. For repeated and useless calls with Z_FINISH, we keep
nuclear@2 772 * returning Z_STREAM_END instead of Z_BUF_ERROR.
nuclear@2 773 */
nuclear@2 774 } else if (strm->avail_in == 0 && flush <= old_flush &&
nuclear@2 775 flush != Z_FINISH) {
nuclear@2 776 ERR_RETURN(strm, Z_BUF_ERROR);
nuclear@2 777 }
nuclear@2 778
nuclear@2 779 /* User must not provide more input after the first FINISH: */
nuclear@2 780 if (s->status == FINISH_STATE && strm->avail_in != 0) {
nuclear@2 781 ERR_RETURN(strm, Z_BUF_ERROR);
nuclear@2 782 }
nuclear@2 783
nuclear@2 784 /* Start a new block or continue the current one.
nuclear@2 785 */
nuclear@2 786 if (strm->avail_in != 0 || s->lookahead != 0 ||
nuclear@2 787 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
nuclear@2 788 block_state bstate;
nuclear@2 789
nuclear@2 790 bstate = (*(configuration_table[s->level].func))(s, flush);
nuclear@2 791
nuclear@2 792 if (bstate == finish_started || bstate == finish_done) {
nuclear@2 793 s->status = FINISH_STATE;
nuclear@2 794 }
nuclear@2 795 if (bstate == need_more || bstate == finish_started) {
nuclear@2 796 if (strm->avail_out == 0) {
nuclear@2 797 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
nuclear@2 798 }
nuclear@2 799 return Z_OK;
nuclear@2 800 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
nuclear@2 801 * of deflate should use the same flush parameter to make sure
nuclear@2 802 * that the flush is complete. So we don't have to output an
nuclear@2 803 * empty block here, this will be done at next call. This also
nuclear@2 804 * ensures that for a very small output buffer, we emit at most
nuclear@2 805 * one empty block.
nuclear@2 806 */
nuclear@2 807 }
nuclear@2 808 if (bstate == block_done) {
nuclear@2 809 if (flush == Z_PARTIAL_FLUSH) {
nuclear@2 810 _tr_align(s);
nuclear@2 811 } else { /* FULL_FLUSH or SYNC_FLUSH */
nuclear@2 812 _tr_stored_block(s, (char*)0, 0L, 0);
nuclear@2 813 /* For a full flush, this empty block will be recognized
nuclear@2 814 * as a special marker by inflate_sync().
nuclear@2 815 */
nuclear@2 816 if (flush == Z_FULL_FLUSH) {
nuclear@2 817 CLEAR_HASH(s); /* forget history */
nuclear@2 818 }
nuclear@2 819 }
nuclear@2 820 flush_pending(strm);
nuclear@2 821 if (strm->avail_out == 0) {
nuclear@2 822 s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
nuclear@2 823 return Z_OK;
nuclear@2 824 }
nuclear@2 825 }
nuclear@2 826 }
nuclear@2 827 Assert(strm->avail_out > 0, "bug2");
nuclear@2 828
nuclear@2 829 if (flush != Z_FINISH) return Z_OK;
nuclear@2 830 if (s->wrap <= 0) return Z_STREAM_END;
nuclear@2 831
nuclear@2 832 /* Write the trailer */
nuclear@2 833 #ifdef GZIP
nuclear@2 834 if (s->wrap == 2) {
nuclear@2 835 put_byte(s, (Byte)(strm->adler & 0xff));
nuclear@2 836 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
nuclear@2 837 put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
nuclear@2 838 put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
nuclear@2 839 put_byte(s, (Byte)(strm->total_in & 0xff));
nuclear@2 840 put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
nuclear@2 841 put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
nuclear@2 842 put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
nuclear@2 843 }
nuclear@2 844 else
nuclear@2 845 #endif
nuclear@2 846 {
nuclear@2 847 putShortMSB(s, (uInt)(strm->adler >> 16));
nuclear@2 848 putShortMSB(s, (uInt)(strm->adler & 0xffff));
nuclear@2 849 }
nuclear@2 850 flush_pending(strm);
nuclear@2 851 /* If avail_out is zero, the application will call deflate again
nuclear@2 852 * to flush the rest.
nuclear@2 853 */
nuclear@2 854 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
nuclear@2 855 return s->pending != 0 ? Z_OK : Z_STREAM_END;
nuclear@2 856 }
nuclear@2 857
nuclear@2 858 /* ========================================================================= */
nuclear@2 859 int ZEXPORT deflateEnd (strm)
nuclear@2 860 z_streamp strm;
nuclear@2 861 {
nuclear@2 862 int status;
nuclear@2 863
nuclear@2 864 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
nuclear@2 865
nuclear@2 866 status = strm->state->status;
nuclear@2 867 if (status != INIT_STATE &&
nuclear@2 868 status != EXTRA_STATE &&
nuclear@2 869 status != NAME_STATE &&
nuclear@2 870 status != COMMENT_STATE &&
nuclear@2 871 status != HCRC_STATE &&
nuclear@2 872 status != BUSY_STATE &&
nuclear@2 873 status != FINISH_STATE) {
nuclear@2 874 return Z_STREAM_ERROR;
nuclear@2 875 }
nuclear@2 876
nuclear@2 877 /* Deallocate in reverse order of allocations: */
nuclear@2 878 TRY_FREE(strm, strm->state->pending_buf);
nuclear@2 879 TRY_FREE(strm, strm->state->head);
nuclear@2 880 TRY_FREE(strm, strm->state->prev);
nuclear@2 881 TRY_FREE(strm, strm->state->window);
nuclear@2 882
nuclear@2 883 ZFREE(strm, strm->state);
nuclear@2 884 strm->state = Z_NULL;
nuclear@2 885
nuclear@2 886 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
nuclear@2 887 }
nuclear@2 888
nuclear@2 889 /* =========================================================================
nuclear@2 890 * Copy the source state to the destination state.
nuclear@2 891 * To simplify the source, this is not supported for 16-bit MSDOS (which
nuclear@2 892 * doesn't have enough memory anyway to duplicate compression states).
nuclear@2 893 */
nuclear@2 894 int ZEXPORT deflateCopy (dest, source)
nuclear@2 895 z_streamp dest;
nuclear@2 896 z_streamp source;
nuclear@2 897 {
nuclear@2 898 #ifdef MAXSEG_64K
nuclear@2 899 return Z_STREAM_ERROR;
nuclear@2 900 #else
nuclear@2 901 deflate_state *ds;
nuclear@2 902 deflate_state *ss;
nuclear@2 903 ushf *overlay;
nuclear@2 904
nuclear@2 905
nuclear@2 906 if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
nuclear@2 907 return Z_STREAM_ERROR;
nuclear@2 908 }
nuclear@2 909
nuclear@2 910 ss = source->state;
nuclear@2 911
nuclear@2 912 zmemcpy(dest, source, sizeof(z_stream));
nuclear@2 913
nuclear@2 914 ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
nuclear@2 915 if (ds == Z_NULL) return Z_MEM_ERROR;
nuclear@2 916 dest->state = (struct internal_state FAR *) ds;
nuclear@2 917 zmemcpy(ds, ss, sizeof(deflate_state));
nuclear@2 918 ds->strm = dest;
nuclear@2 919
nuclear@2 920 ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
nuclear@2 921 ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
nuclear@2 922 ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
nuclear@2 923 overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
nuclear@2 924 ds->pending_buf = (uchf *) overlay;
nuclear@2 925
nuclear@2 926 if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
nuclear@2 927 ds->pending_buf == Z_NULL) {
nuclear@2 928 deflateEnd (dest);
nuclear@2 929 return Z_MEM_ERROR;
nuclear@2 930 }
nuclear@2 931 /* following zmemcpy do not work for 16-bit MSDOS */
nuclear@2 932 zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
nuclear@2 933 zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
nuclear@2 934 zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
nuclear@2 935 zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
nuclear@2 936
nuclear@2 937 ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
nuclear@2 938 ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
nuclear@2 939 ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
nuclear@2 940
nuclear@2 941 ds->l_desc.dyn_tree = ds->dyn_ltree;
nuclear@2 942 ds->d_desc.dyn_tree = ds->dyn_dtree;
nuclear@2 943 ds->bl_desc.dyn_tree = ds->bl_tree;
nuclear@2 944
nuclear@2 945 return Z_OK;
nuclear@2 946 #endif /* MAXSEG_64K */
nuclear@2 947 }
nuclear@2 948
nuclear@2 949 /* ===========================================================================
nuclear@2 950 * Read a new buffer from the current input stream, update the adler32
nuclear@2 951 * and total number of bytes read. All deflate() input goes through
nuclear@2 952 * this function so some applications may wish to modify it to avoid
nuclear@2 953 * allocating a large strm->next_in buffer and copying from it.
nuclear@2 954 * (See also flush_pending()).
nuclear@2 955 */
nuclear@2 956 local int read_buf(strm, buf, size)
nuclear@2 957 z_streamp strm;
nuclear@2 958 Bytef *buf;
nuclear@2 959 unsigned size;
nuclear@2 960 {
nuclear@2 961 unsigned len = strm->avail_in;
nuclear@2 962
nuclear@2 963 if (len > size) len = size;
nuclear@2 964 if (len == 0) return 0;
nuclear@2 965
nuclear@2 966 strm->avail_in -= len;
nuclear@2 967
nuclear@2 968 if (strm->state->wrap == 1) {
nuclear@2 969 strm->adler = adler32(strm->adler, strm->next_in, len);
nuclear@2 970 }
nuclear@2 971 #ifdef GZIP
nuclear@2 972 else if (strm->state->wrap == 2) {
nuclear@2 973 strm->adler = crc32(strm->adler, strm->next_in, len);
nuclear@2 974 }
nuclear@2 975 #endif
nuclear@2 976 zmemcpy(buf, strm->next_in, len);
nuclear@2 977 strm->next_in += len;
nuclear@2 978 strm->total_in += len;
nuclear@2 979
nuclear@2 980 return (int)len;
nuclear@2 981 }
nuclear@2 982
nuclear@2 983 /* ===========================================================================
nuclear@2 984 * Initialize the "longest match" routines for a new zlib stream
nuclear@2 985 */
nuclear@2 986 local void lm_init (s)
nuclear@2 987 deflate_state *s;
nuclear@2 988 {
nuclear@2 989 s->window_size = (ulg)2L*s->w_size;
nuclear@2 990
nuclear@2 991 CLEAR_HASH(s);
nuclear@2 992
nuclear@2 993 /* Set the default configuration parameters:
nuclear@2 994 */
nuclear@2 995 s->max_lazy_match = configuration_table[s->level].max_lazy;
nuclear@2 996 s->good_match = configuration_table[s->level].good_length;
nuclear@2 997 s->nice_match = configuration_table[s->level].nice_length;
nuclear@2 998 s->max_chain_length = configuration_table[s->level].max_chain;
nuclear@2 999
nuclear@2 1000 s->strstart = 0;
nuclear@2 1001 s->block_start = 0L;
nuclear@2 1002 s->lookahead = 0;
nuclear@2 1003 s->match_length = s->prev_length = MIN_MATCH-1;
nuclear@2 1004 s->match_available = 0;
nuclear@2 1005 s->ins_h = 0;
nuclear@2 1006 #ifndef FASTEST
nuclear@2 1007 #ifdef ASMV
nuclear@2 1008 match_init(); /* initialize the asm code */
nuclear@2 1009 #endif
nuclear@2 1010 #endif
nuclear@2 1011 }
nuclear@2 1012
nuclear@2 1013 #ifndef FASTEST
nuclear@2 1014 /* ===========================================================================
nuclear@2 1015 * Set match_start to the longest match starting at the given string and
nuclear@2 1016 * return its length. Matches shorter or equal to prev_length are discarded,
nuclear@2 1017 * in which case the result is equal to prev_length and match_start is
nuclear@2 1018 * garbage.
nuclear@2 1019 * IN assertions: cur_match is the head of the hash chain for the current
nuclear@2 1020 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
nuclear@2 1021 * OUT assertion: the match length is not greater than s->lookahead.
nuclear@2 1022 */
nuclear@2 1023 #ifndef ASMV
nuclear@2 1024 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
nuclear@2 1025 * match.S. The code will be functionally equivalent.
nuclear@2 1026 */
nuclear@2 1027 local uInt longest_match(s, cur_match)
nuclear@2 1028 deflate_state *s;
nuclear@2 1029 IPos cur_match; /* current match */
nuclear@2 1030 {
nuclear@2 1031 unsigned chain_length = s->max_chain_length;/* max hash chain length */
nuclear@2 1032 register Bytef *scan = s->window + s->strstart; /* current string */
nuclear@2 1033 register Bytef *match; /* matched string */
nuclear@2 1034 register int len; /* length of current match */
nuclear@2 1035 int best_len = s->prev_length; /* best match length so far */
nuclear@2 1036 int nice_match = s->nice_match; /* stop if match long enough */
nuclear@2 1037 IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
nuclear@2 1038 s->strstart - (IPos)MAX_DIST(s) : NIL;
nuclear@2 1039 /* Stop when cur_match becomes <= limit. To simplify the code,
nuclear@2 1040 * we prevent matches with the string of window index 0.
nuclear@2 1041 */
nuclear@2 1042 Posf *prev = s->prev;
nuclear@2 1043 uInt wmask = s->w_mask;
nuclear@2 1044
nuclear@2 1045 #ifdef UNALIGNED_OK
nuclear@2 1046 /* Compare two bytes at a time. Note: this is not always beneficial.
nuclear@2 1047 * Try with and without -DUNALIGNED_OK to check.
nuclear@2 1048 */
nuclear@2 1049 register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
nuclear@2 1050 register ush scan_start = *(ushf*)scan;
nuclear@2 1051 register ush scan_end = *(ushf*)(scan+best_len-1);
nuclear@2 1052 #else
nuclear@2 1053 register Bytef *strend = s->window + s->strstart + MAX_MATCH;
nuclear@2 1054 register Byte scan_end1 = scan[best_len-1];
nuclear@2 1055 register Byte scan_end = scan[best_len];
nuclear@2 1056 #endif
nuclear@2 1057
nuclear@2 1058 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
nuclear@2 1059 * It is easy to get rid of this optimization if necessary.
nuclear@2 1060 */
nuclear@2 1061 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
nuclear@2 1062
nuclear@2 1063 /* Do not waste too much time if we already have a good match: */
nuclear@2 1064 if (s->prev_length >= s->good_match) {
nuclear@2 1065 chain_length >>= 2;
nuclear@2 1066 }
nuclear@2 1067 /* Do not look for matches beyond the end of the input. This is necessary
nuclear@2 1068 * to make deflate deterministic.
nuclear@2 1069 */
nuclear@2 1070 if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
nuclear@2 1071
nuclear@2 1072 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
nuclear@2 1073
nuclear@2 1074 do {
nuclear@2 1075 Assert(cur_match < s->strstart, "no future");
nuclear@2 1076 match = s->window + cur_match;
nuclear@2 1077
nuclear@2 1078 /* Skip to next match if the match length cannot increase
nuclear@2 1079 * or if the match length is less than 2. Note that the checks below
nuclear@2 1080 * for insufficient lookahead only occur occasionally for performance
nuclear@2 1081 * reasons. Therefore uninitialized memory will be accessed, and
nuclear@2 1082 * conditional jumps will be made that depend on those values.
nuclear@2 1083 * However the length of the match is limited to the lookahead, so
nuclear@2 1084 * the output of deflate is not affected by the uninitialized values.
nuclear@2 1085 */
nuclear@2 1086 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
nuclear@2 1087 /* This code assumes sizeof(unsigned short) == 2. Do not use
nuclear@2 1088 * UNALIGNED_OK if your compiler uses a different size.
nuclear@2 1089 */
nuclear@2 1090 if (*(ushf*)(match+best_len-1) != scan_end ||
nuclear@2 1091 *(ushf*)match != scan_start) continue;
nuclear@2 1092
nuclear@2 1093 /* It is not necessary to compare scan[2] and match[2] since they are
nuclear@2 1094 * always equal when the other bytes match, given that the hash keys
nuclear@2 1095 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
nuclear@2 1096 * strstart+3, +5, ... up to strstart+257. We check for insufficient
nuclear@2 1097 * lookahead only every 4th comparison; the 128th check will be made
nuclear@2 1098 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
nuclear@2 1099 * necessary to put more guard bytes at the end of the window, or
nuclear@2 1100 * to check more often for insufficient lookahead.
nuclear@2 1101 */
nuclear@2 1102 Assert(scan[2] == match[2], "scan[2]?");
nuclear@2 1103 scan++, match++;
nuclear@2 1104 do {
nuclear@2 1105 } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
nuclear@2 1106 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
nuclear@2 1107 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
nuclear@2 1108 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
nuclear@2 1109 scan < strend);
nuclear@2 1110 /* The funny "do {}" generates better code on most compilers */
nuclear@2 1111
nuclear@2 1112 /* Here, scan <= window+strstart+257 */
nuclear@2 1113 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
nuclear@2 1114 if (*scan == *match) scan++;
nuclear@2 1115
nuclear@2 1116 len = (MAX_MATCH - 1) - (int)(strend-scan);
nuclear@2 1117 scan = strend - (MAX_MATCH-1);
nuclear@2 1118
nuclear@2 1119 #else /* UNALIGNED_OK */
nuclear@2 1120
nuclear@2 1121 if (match[best_len] != scan_end ||
nuclear@2 1122 match[best_len-1] != scan_end1 ||
nuclear@2 1123 *match != *scan ||
nuclear@2 1124 *++match != scan[1]) continue;
nuclear@2 1125
nuclear@2 1126 /* The check at best_len-1 can be removed because it will be made
nuclear@2 1127 * again later. (This heuristic is not always a win.)
nuclear@2 1128 * It is not necessary to compare scan[2] and match[2] since they
nuclear@2 1129 * are always equal when the other bytes match, given that
nuclear@2 1130 * the hash keys are equal and that HASH_BITS >= 8.
nuclear@2 1131 */
nuclear@2 1132 scan += 2, match++;
nuclear@2 1133 Assert(*scan == *match, "match[2]?");
nuclear@2 1134
nuclear@2 1135 /* We check for insufficient lookahead only every 8th comparison;
nuclear@2 1136 * the 256th check will be made at strstart+258.
nuclear@2 1137 */
nuclear@2 1138 do {
nuclear@2 1139 } while (*++scan == *++match && *++scan == *++match &&
nuclear@2 1140 *++scan == *++match && *++scan == *++match &&
nuclear@2 1141 *++scan == *++match && *++scan == *++match &&
nuclear@2 1142 *++scan == *++match && *++scan == *++match &&
nuclear@2 1143 scan < strend);
nuclear@2 1144
nuclear@2 1145 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
nuclear@2 1146
nuclear@2 1147 len = MAX_MATCH - (int)(strend - scan);
nuclear@2 1148 scan = strend - MAX_MATCH;
nuclear@2 1149
nuclear@2 1150 #endif /* UNALIGNED_OK */
nuclear@2 1151
nuclear@2 1152 if (len > best_len) {
nuclear@2 1153 s->match_start = cur_match;
nuclear@2 1154 best_len = len;
nuclear@2 1155 if (len >= nice_match) break;
nuclear@2 1156 #ifdef UNALIGNED_OK
nuclear@2 1157 scan_end = *(ushf*)(scan+best_len-1);
nuclear@2 1158 #else
nuclear@2 1159 scan_end1 = scan[best_len-1];
nuclear@2 1160 scan_end = scan[best_len];
nuclear@2 1161 #endif
nuclear@2 1162 }
nuclear@2 1163 } while ((cur_match = prev[cur_match & wmask]) > limit
nuclear@2 1164 && --chain_length != 0);
nuclear@2 1165
nuclear@2 1166 if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
nuclear@2 1167 return s->lookahead;
nuclear@2 1168 }
nuclear@2 1169 #endif /* ASMV */
nuclear@2 1170 #endif /* FASTEST */
nuclear@2 1171
nuclear@2 1172 /* ---------------------------------------------------------------------------
nuclear@2 1173 * Optimized version for level == 1 or strategy == Z_RLE only
nuclear@2 1174 */
nuclear@2 1175 local uInt longest_match_fast(s, cur_match)
nuclear@2 1176 deflate_state *s;
nuclear@2 1177 IPos cur_match; /* current match */
nuclear@2 1178 {
nuclear@2 1179 register Bytef *scan = s->window + s->strstart; /* current string */
nuclear@2 1180 register Bytef *match; /* matched string */
nuclear@2 1181 register int len; /* length of current match */
nuclear@2 1182 register Bytef *strend = s->window + s->strstart + MAX_MATCH;
nuclear@2 1183
nuclear@2 1184 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
nuclear@2 1185 * It is easy to get rid of this optimization if necessary.
nuclear@2 1186 */
nuclear@2 1187 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
nuclear@2 1188
nuclear@2 1189 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
nuclear@2 1190
nuclear@2 1191 Assert(cur_match < s->strstart, "no future");
nuclear@2 1192
nuclear@2 1193 match = s->window + cur_match;
nuclear@2 1194
nuclear@2 1195 /* Return failure if the match length is less than 2:
nuclear@2 1196 */
nuclear@2 1197 if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
nuclear@2 1198
nuclear@2 1199 /* The check at best_len-1 can be removed because it will be made
nuclear@2 1200 * again later. (This heuristic is not always a win.)
nuclear@2 1201 * It is not necessary to compare scan[2] and match[2] since they
nuclear@2 1202 * are always equal when the other bytes match, given that
nuclear@2 1203 * the hash keys are equal and that HASH_BITS >= 8.
nuclear@2 1204 */
nuclear@2 1205 scan += 2, match += 2;
nuclear@2 1206 Assert(*scan == *match, "match[2]?");
nuclear@2 1207
nuclear@2 1208 /* We check for insufficient lookahead only every 8th comparison;
nuclear@2 1209 * the 256th check will be made at strstart+258.
nuclear@2 1210 */
nuclear@2 1211 do {
nuclear@2 1212 } while (*++scan == *++match && *++scan == *++match &&
nuclear@2 1213 *++scan == *++match && *++scan == *++match &&
nuclear@2 1214 *++scan == *++match && *++scan == *++match &&
nuclear@2 1215 *++scan == *++match && *++scan == *++match &&
nuclear@2 1216 scan < strend);
nuclear@2 1217
nuclear@2 1218 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
nuclear@2 1219
nuclear@2 1220 len = MAX_MATCH - (int)(strend - scan);
nuclear@2 1221
nuclear@2 1222 if (len < MIN_MATCH) return MIN_MATCH - 1;
nuclear@2 1223
nuclear@2 1224 s->match_start = cur_match;
nuclear@2 1225 return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
nuclear@2 1226 }
nuclear@2 1227
nuclear@2 1228 #ifdef DEBUG
nuclear@2 1229 /* ===========================================================================
nuclear@2 1230 * Check that the match at match_start is indeed a match.
nuclear@2 1231 */
nuclear@2 1232 local void check_match(s, start, match, length)
nuclear@2 1233 deflate_state *s;
nuclear@2 1234 IPos start, match;
nuclear@2 1235 int length;
nuclear@2 1236 {
nuclear@2 1237 /* check that the match is indeed a match */
nuclear@2 1238 if (zmemcmp(s->window + match,
nuclear@2 1239 s->window + start, length) != EQUAL) {
nuclear@2 1240 fprintf(stderr, " start %u, match %u, length %d\n",
nuclear@2 1241 start, match, length);
nuclear@2 1242 do {
nuclear@2 1243 fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
nuclear@2 1244 } while (--length != 0);
nuclear@2 1245 z_error("invalid match");
nuclear@2 1246 }
nuclear@2 1247 if (z_verbose > 1) {
nuclear@2 1248 fprintf(stderr,"\\[%d,%d]", start-match, length);
nuclear@2 1249 do { putc(s->window[start++], stderr); } while (--length != 0);
nuclear@2 1250 }
nuclear@2 1251 }
nuclear@2 1252 #else
nuclear@2 1253 # define check_match(s, start, match, length)
nuclear@2 1254 #endif /* DEBUG */
nuclear@2 1255
nuclear@2 1256 /* ===========================================================================
nuclear@2 1257 * Fill the window when the lookahead becomes insufficient.
nuclear@2 1258 * Updates strstart and lookahead.
nuclear@2 1259 *
nuclear@2 1260 * IN assertion: lookahead < MIN_LOOKAHEAD
nuclear@2 1261 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
nuclear@2 1262 * At least one byte has been read, or avail_in == 0; reads are
nuclear@2 1263 * performed for at least two bytes (required for the zip translate_eol
nuclear@2 1264 * option -- not supported here).
nuclear@2 1265 */
nuclear@2 1266 local void fill_window(s)
nuclear@2 1267 deflate_state *s;
nuclear@2 1268 {
nuclear@2 1269 register unsigned n, m;
nuclear@2 1270 register Posf *p;
nuclear@2 1271 unsigned more; /* Amount of free space at the end of the window. */
nuclear@2 1272 uInt wsize = s->w_size;
nuclear@2 1273
nuclear@2 1274 do {
nuclear@2 1275 more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
nuclear@2 1276
nuclear@2 1277 /* Deal with !@#$% 64K limit: */
nuclear@2 1278 if (sizeof(int) <= 2) {
nuclear@2 1279 if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
nuclear@2 1280 more = wsize;
nuclear@2 1281
nuclear@2 1282 } else if (more == (unsigned)(-1)) {
nuclear@2 1283 /* Very unlikely, but possible on 16 bit machine if
nuclear@2 1284 * strstart == 0 && lookahead == 1 (input done a byte at time)
nuclear@2 1285 */
nuclear@2 1286 more--;
nuclear@2 1287 }
nuclear@2 1288 }
nuclear@2 1289
nuclear@2 1290 /* If the window is almost full and there is insufficient lookahead,
nuclear@2 1291 * move the upper half to the lower one to make room in the upper half.
nuclear@2 1292 */
nuclear@2 1293 if (s->strstart >= wsize+MAX_DIST(s)) {
nuclear@2 1294
nuclear@2 1295 zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
nuclear@2 1296 s->match_start -= wsize;
nuclear@2 1297 s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
nuclear@2 1298 s->block_start -= (long) wsize;
nuclear@2 1299
nuclear@2 1300 /* Slide the hash table (could be avoided with 32 bit values
nuclear@2 1301 at the expense of memory usage). We slide even when level == 0
nuclear@2 1302 to keep the hash table consistent if we switch back to level > 0
nuclear@2 1303 later. (Using level 0 permanently is not an optimal usage of
nuclear@2 1304 zlib, so we don't care about this pathological case.)
nuclear@2 1305 */
nuclear@2 1306 /* %%% avoid this when Z_RLE */
nuclear@2 1307 n = s->hash_size;
nuclear@2 1308 p = &s->head[n];
nuclear@2 1309 do {
nuclear@2 1310 m = *--p;
nuclear@2 1311 *p = (Pos)(m >= wsize ? m-wsize : NIL);
nuclear@2 1312 } while (--n);
nuclear@2 1313
nuclear@2 1314 n = wsize;
nuclear@2 1315 #ifndef FASTEST
nuclear@2 1316 p = &s->prev[n];
nuclear@2 1317 do {
nuclear@2 1318 m = *--p;
nuclear@2 1319 *p = (Pos)(m >= wsize ? m-wsize : NIL);
nuclear@2 1320 /* If n is not on any hash chain, prev[n] is garbage but
nuclear@2 1321 * its value will never be used.
nuclear@2 1322 */
nuclear@2 1323 } while (--n);
nuclear@2 1324 #endif
nuclear@2 1325 more += wsize;
nuclear@2 1326 }
nuclear@2 1327 if (s->strm->avail_in == 0) return;
nuclear@2 1328
nuclear@2 1329 /* If there was no sliding:
nuclear@2 1330 * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
nuclear@2 1331 * more == window_size - lookahead - strstart
nuclear@2 1332 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
nuclear@2 1333 * => more >= window_size - 2*WSIZE + 2
nuclear@2 1334 * In the BIG_MEM or MMAP case (not yet supported),
nuclear@2 1335 * window_size == input_size + MIN_LOOKAHEAD &&
nuclear@2 1336 * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
nuclear@2 1337 * Otherwise, window_size == 2*WSIZE so more >= 2.
nuclear@2 1338 * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
nuclear@2 1339 */
nuclear@2 1340 Assert(more >= 2, "more < 2");
nuclear@2 1341
nuclear@2 1342 n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
nuclear@2 1343 s->lookahead += n;
nuclear@2 1344
nuclear@2 1345 /* Initialize the hash value now that we have some input: */
nuclear@2 1346 if (s->lookahead >= MIN_MATCH) {
nuclear@2 1347 s->ins_h = s->window[s->strstart];
nuclear@2 1348 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
nuclear@2 1349 #if MIN_MATCH != 3
nuclear@2 1350 Call UPDATE_HASH() MIN_MATCH-3 more times
nuclear@2 1351 #endif
nuclear@2 1352 }
nuclear@2 1353 /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
nuclear@2 1354 * but this is not important since only literal bytes will be emitted.
nuclear@2 1355 */
nuclear@2 1356
nuclear@2 1357 } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
nuclear@2 1358 }
nuclear@2 1359
nuclear@2 1360 /* ===========================================================================
nuclear@2 1361 * Flush the current block, with given end-of-file flag.
nuclear@2 1362 * IN assertion: strstart is set to the end of the current match.
nuclear@2 1363 */
nuclear@2 1364 #define FLUSH_BLOCK_ONLY(s, eof) { \
nuclear@2 1365 _tr_flush_block(s, (s->block_start >= 0L ? \
nuclear@2 1366 (charf *)&s->window[(unsigned)s->block_start] : \
nuclear@2 1367 (charf *)Z_NULL), \
nuclear@2 1368 (ulg)((long)s->strstart - s->block_start), \
nuclear@2 1369 (eof)); \
nuclear@2 1370 s->block_start = s->strstart; \
nuclear@2 1371 flush_pending(s->strm); \
nuclear@2 1372 Tracev((stderr,"[FLUSH]")); \
nuclear@2 1373 }
nuclear@2 1374
nuclear@2 1375 /* Same but force premature exit if necessary. */
nuclear@2 1376 #define FLUSH_BLOCK(s, eof) { \
nuclear@2 1377 FLUSH_BLOCK_ONLY(s, eof); \
nuclear@2 1378 if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
nuclear@2 1379 }
nuclear@2 1380
nuclear@2 1381 /* ===========================================================================
nuclear@2 1382 * Copy without compression as much as possible from the input stream, return
nuclear@2 1383 * the current block state.
nuclear@2 1384 * This function does not insert new strings in the dictionary since
nuclear@2 1385 * uncompressible data is probably not useful. This function is used
nuclear@2 1386 * only for the level=0 compression option.
nuclear@2 1387 * NOTE: this function should be optimized to avoid extra copying from
nuclear@2 1388 * window to pending_buf.
nuclear@2 1389 */
nuclear@2 1390 local block_state deflate_stored(s, flush)
nuclear@2 1391 deflate_state *s;
nuclear@2 1392 int flush;
nuclear@2 1393 {
nuclear@2 1394 /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
nuclear@2 1395 * to pending_buf_size, and each stored block has a 5 byte header:
nuclear@2 1396 */
nuclear@2 1397 ulg max_block_size = 0xffff;
nuclear@2 1398 ulg max_start;
nuclear@2 1399
nuclear@2 1400 if (max_block_size > s->pending_buf_size - 5) {
nuclear@2 1401 max_block_size = s->pending_buf_size - 5;
nuclear@2 1402 }
nuclear@2 1403
nuclear@2 1404 /* Copy as much as possible from input to output: */
nuclear@2 1405 for (;;) {
nuclear@2 1406 /* Fill the window as much as possible: */
nuclear@2 1407 if (s->lookahead <= 1) {
nuclear@2 1408
nuclear@2 1409 Assert(s->strstart < s->w_size+MAX_DIST(s) ||
nuclear@2 1410 s->block_start >= (long)s->w_size, "slide too late");
nuclear@2 1411
nuclear@2 1412 fill_window(s);
nuclear@2 1413 if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
nuclear@2 1414
nuclear@2 1415 if (s->lookahead == 0) break; /* flush the current block */
nuclear@2 1416 }
nuclear@2 1417 Assert(s->block_start >= 0L, "block gone");
nuclear@2 1418
nuclear@2 1419 s->strstart += s->lookahead;
nuclear@2 1420 s->lookahead = 0;
nuclear@2 1421
nuclear@2 1422 /* Emit a stored block if pending_buf will be full: */
nuclear@2 1423 max_start = s->block_start + max_block_size;
nuclear@2 1424 if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
nuclear@2 1425 /* strstart == 0 is possible when wraparound on 16-bit machine */
nuclear@2 1426 s->lookahead = (uInt)(s->strstart - max_start);
nuclear@2 1427 s->strstart = (uInt)max_start;
nuclear@2 1428 FLUSH_BLOCK(s, 0);
nuclear@2 1429 }
nuclear@2 1430 /* Flush if we may have to slide, otherwise block_start may become
nuclear@2 1431 * negative and the data will be gone:
nuclear@2 1432 */
nuclear@2 1433 if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
nuclear@2 1434 FLUSH_BLOCK(s, 0);
nuclear@2 1435 }
nuclear@2 1436 }
nuclear@2 1437 FLUSH_BLOCK(s, flush == Z_FINISH);
nuclear@2 1438 return flush == Z_FINISH ? finish_done : block_done;
nuclear@2 1439 }
nuclear@2 1440
nuclear@2 1441 /* ===========================================================================
nuclear@2 1442 * Compress as much as possible from the input stream, return the current
nuclear@2 1443 * block state.
nuclear@2 1444 * This function does not perform lazy evaluation of matches and inserts
nuclear@2 1445 * new strings in the dictionary only for unmatched strings or for short
nuclear@2 1446 * matches. It is used only for the fast compression options.
nuclear@2 1447 */
nuclear@2 1448 local block_state deflate_fast(s, flush)
nuclear@2 1449 deflate_state *s;
nuclear@2 1450 int flush;
nuclear@2 1451 {
nuclear@2 1452 IPos hash_head = NIL; /* head of the hash chain */
nuclear@2 1453 int bflush; /* set if current block must be flushed */
nuclear@2 1454
nuclear@2 1455 for (;;) {
nuclear@2 1456 /* Make sure that we always have enough lookahead, except
nuclear@2 1457 * at the end of the input file. We need MAX_MATCH bytes
nuclear@2 1458 * for the next match, plus MIN_MATCH bytes to insert the
nuclear@2 1459 * string following the next match.
nuclear@2 1460 */
nuclear@2 1461 if (s->lookahead < MIN_LOOKAHEAD) {
nuclear@2 1462 fill_window(s);
nuclear@2 1463 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
nuclear@2 1464 return need_more;
nuclear@2 1465 }
nuclear@2 1466 if (s->lookahead == 0) break; /* flush the current block */
nuclear@2 1467 }
nuclear@2 1468
nuclear@2 1469 /* Insert the string window[strstart .. strstart+2] in the
nuclear@2 1470 * dictionary, and set hash_head to the head of the hash chain:
nuclear@2 1471 */
nuclear@2 1472 if (s->lookahead >= MIN_MATCH) {
nuclear@2 1473 INSERT_STRING(s, s->strstart, hash_head);
nuclear@2 1474 }
nuclear@2 1475
nuclear@2 1476 /* Find the longest match, discarding those <= prev_length.
nuclear@2 1477 * At this point we have always match_length < MIN_MATCH
nuclear@2 1478 */
nuclear@2 1479 if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
nuclear@2 1480 /* To simplify the code, we prevent matches with the string
nuclear@2 1481 * of window index 0 (in particular we have to avoid a match
nuclear@2 1482 * of the string with itself at the start of the input file).
nuclear@2 1483 */
nuclear@2 1484 #ifdef FASTEST
nuclear@2 1485 if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) ||
nuclear@2 1486 (s->strategy == Z_RLE && s->strstart - hash_head == 1)) {
nuclear@2 1487 s->match_length = longest_match_fast (s, hash_head);
nuclear@2 1488 }
nuclear@2 1489 #else
nuclear@2 1490 if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
nuclear@2 1491 s->match_length = longest_match (s, hash_head);
nuclear@2 1492 } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
nuclear@2 1493 s->match_length = longest_match_fast (s, hash_head);
nuclear@2 1494 }
nuclear@2 1495 #endif
nuclear@2 1496 /* longest_match() or longest_match_fast() sets match_start */
nuclear@2 1497 }
nuclear@2 1498 if (s->match_length >= MIN_MATCH) {
nuclear@2 1499 check_match(s, s->strstart, s->match_start, s->match_length);
nuclear@2 1500
nuclear@2 1501 _tr_tally_dist(s, s->strstart - s->match_start,
nuclear@2 1502 s->match_length - MIN_MATCH, bflush);
nuclear@2 1503
nuclear@2 1504 s->lookahead -= s->match_length;
nuclear@2 1505
nuclear@2 1506 /* Insert new strings in the hash table only if the match length
nuclear@2 1507 * is not too large. This saves time but degrades compression.
nuclear@2 1508 */
nuclear@2 1509 #ifndef FASTEST
nuclear@2 1510 if (s->match_length <= s->max_insert_length &&
nuclear@2 1511 s->lookahead >= MIN_MATCH) {
nuclear@2 1512 s->match_length--; /* string at strstart already in table */
nuclear@2 1513 do {
nuclear@2 1514 s->strstart++;
nuclear@2 1515 INSERT_STRING(s, s->strstart, hash_head);
nuclear@2 1516 /* strstart never exceeds WSIZE-MAX_MATCH, so there are
nuclear@2 1517 * always MIN_MATCH bytes ahead.
nuclear@2 1518 */
nuclear@2 1519 } while (--s->match_length != 0);
nuclear@2 1520 s->strstart++;
nuclear@2 1521 } else
nuclear@2 1522 #endif
nuclear@2 1523 {
nuclear@2 1524 s->strstart += s->match_length;
nuclear@2 1525 s->match_length = 0;
nuclear@2 1526 s->ins_h = s->window[s->strstart];
nuclear@2 1527 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
nuclear@2 1528 #if MIN_MATCH != 3
nuclear@2 1529 Call UPDATE_HASH() MIN_MATCH-3 more times
nuclear@2 1530 #endif
nuclear@2 1531 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
nuclear@2 1532 * matter since it will be recomputed at next deflate call.
nuclear@2 1533 */
nuclear@2 1534 }
nuclear@2 1535 } else {
nuclear@2 1536 /* No match, output a literal byte */
nuclear@2 1537 Tracevv((stderr,"%c", s->window[s->strstart]));
nuclear@2 1538 _tr_tally_lit (s, s->window[s->strstart], bflush);
nuclear@2 1539 s->lookahead--;
nuclear@2 1540 s->strstart++;
nuclear@2 1541 }
nuclear@2 1542 if (bflush) FLUSH_BLOCK(s, 0);
nuclear@2 1543 }
nuclear@2 1544 FLUSH_BLOCK(s, flush == Z_FINISH);
nuclear@2 1545 return flush == Z_FINISH ? finish_done : block_done;
nuclear@2 1546 }
nuclear@2 1547
nuclear@2 1548 #ifndef FASTEST
nuclear@2 1549 /* ===========================================================================
nuclear@2 1550 * Same as above, but achieves better compression. We use a lazy
nuclear@2 1551 * evaluation for matches: a match is finally adopted only if there is
nuclear@2 1552 * no better match at the next window position.
nuclear@2 1553 */
nuclear@2 1554 local block_state deflate_slow(s, flush)
nuclear@2 1555 deflate_state *s;
nuclear@2 1556 int flush;
nuclear@2 1557 {
nuclear@2 1558 IPos hash_head = NIL; /* head of hash chain */
nuclear@2 1559 int bflush; /* set if current block must be flushed */
nuclear@2 1560
nuclear@2 1561 /* Process the input block. */
nuclear@2 1562 for (;;) {
nuclear@2 1563 /* Make sure that we always have enough lookahead, except
nuclear@2 1564 * at the end of the input file. We need MAX_MATCH bytes
nuclear@2 1565 * for the next match, plus MIN_MATCH bytes to insert the
nuclear@2 1566 * string following the next match.
nuclear@2 1567 */
nuclear@2 1568 if (s->lookahead < MIN_LOOKAHEAD) {
nuclear@2 1569 fill_window(s);
nuclear@2 1570 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
nuclear@2 1571 return need_more;
nuclear@2 1572 }
nuclear@2 1573 if (s->lookahead == 0) break; /* flush the current block */
nuclear@2 1574 }
nuclear@2 1575
nuclear@2 1576 /* Insert the string window[strstart .. strstart+2] in the
nuclear@2 1577 * dictionary, and set hash_head to the head of the hash chain:
nuclear@2 1578 */
nuclear@2 1579 if (s->lookahead >= MIN_MATCH) {
nuclear@2 1580 INSERT_STRING(s, s->strstart, hash_head);
nuclear@2 1581 }
nuclear@2 1582
nuclear@2 1583 /* Find the longest match, discarding those <= prev_length.
nuclear@2 1584 */
nuclear@2 1585 s->prev_length = s->match_length, s->prev_match = s->match_start;
nuclear@2 1586 s->match_length = MIN_MATCH-1;
nuclear@2 1587
nuclear@2 1588 if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
nuclear@2 1589 s->strstart - hash_head <= MAX_DIST(s)) {
nuclear@2 1590 /* To simplify the code, we prevent matches with the string
nuclear@2 1591 * of window index 0 (in particular we have to avoid a match
nuclear@2 1592 * of the string with itself at the start of the input file).
nuclear@2 1593 */
nuclear@2 1594 if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
nuclear@2 1595 s->match_length = longest_match (s, hash_head);
nuclear@2 1596 } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
nuclear@2 1597 s->match_length = longest_match_fast (s, hash_head);
nuclear@2 1598 }
nuclear@2 1599 /* longest_match() or longest_match_fast() sets match_start */
nuclear@2 1600
nuclear@2 1601 if (s->match_length <= 5 && (s->strategy == Z_FILTERED
nuclear@2 1602 #if TOO_FAR <= 32767
nuclear@2 1603 || (s->match_length == MIN_MATCH &&
nuclear@2 1604 s->strstart - s->match_start > TOO_FAR)
nuclear@2 1605 #endif
nuclear@2 1606 )) {
nuclear@2 1607
nuclear@2 1608 /* If prev_match is also MIN_MATCH, match_start is garbage
nuclear@2 1609 * but we will ignore the current match anyway.
nuclear@2 1610 */
nuclear@2 1611 s->match_length = MIN_MATCH-1;
nuclear@2 1612 }
nuclear@2 1613 }
nuclear@2 1614 /* If there was a match at the previous step and the current
nuclear@2 1615 * match is not better, output the previous match:
nuclear@2 1616 */
nuclear@2 1617 if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
nuclear@2 1618 uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
nuclear@2 1619 /* Do not insert strings in hash table beyond this. */
nuclear@2 1620
nuclear@2 1621 check_match(s, s->strstart-1, s->prev_match, s->prev_length);
nuclear@2 1622
nuclear@2 1623 _tr_tally_dist(s, s->strstart -1 - s->prev_match,
nuclear@2 1624 s->prev_length - MIN_MATCH, bflush);
nuclear@2 1625
nuclear@2 1626 /* Insert in hash table all strings up to the end of the match.
nuclear@2 1627 * strstart-1 and strstart are already inserted. If there is not
nuclear@2 1628 * enough lookahead, the last two strings are not inserted in
nuclear@2 1629 * the hash table.
nuclear@2 1630 */
nuclear@2 1631 s->lookahead -= s->prev_length-1;
nuclear@2 1632 s->prev_length -= 2;
nuclear@2 1633 do {
nuclear@2 1634 if (++s->strstart <= max_insert) {
nuclear@2 1635 INSERT_STRING(s, s->strstart, hash_head);
nuclear@2 1636 }
nuclear@2 1637 } while (--s->prev_length != 0);
nuclear@2 1638 s->match_available = 0;
nuclear@2 1639 s->match_length = MIN_MATCH-1;
nuclear@2 1640 s->strstart++;
nuclear@2 1641
nuclear@2 1642 if (bflush) FLUSH_BLOCK(s, 0);
nuclear@2 1643
nuclear@2 1644 } else if (s->match_available) {
nuclear@2 1645 /* If there was no match at the previous position, output a
nuclear@2 1646 * single literal. If there was a match but the current match
nuclear@2 1647 * is longer, truncate the previous match to a single literal.
nuclear@2 1648 */
nuclear@2 1649 Tracevv((stderr,"%c", s->window[s->strstart-1]));
nuclear@2 1650 _tr_tally_lit(s, s->window[s->strstart-1], bflush);
nuclear@2 1651 if (bflush) {
nuclear@2 1652 FLUSH_BLOCK_ONLY(s, 0);
nuclear@2 1653 }
nuclear@2 1654 s->strstart++;
nuclear@2 1655 s->lookahead--;
nuclear@2 1656 if (s->strm->avail_out == 0) return need_more;
nuclear@2 1657 } else {
nuclear@2 1658 /* There is no previous match to compare with, wait for
nuclear@2 1659 * the next step to decide.
nuclear@2 1660 */
nuclear@2 1661 s->match_available = 1;
nuclear@2 1662 s->strstart++;
nuclear@2 1663 s->lookahead--;
nuclear@2 1664 }
nuclear@2 1665 }
nuclear@2 1666 Assert (flush != Z_NO_FLUSH, "no flush?");
nuclear@2 1667 if (s->match_available) {
nuclear@2 1668 Tracevv((stderr,"%c", s->window[s->strstart-1]));
nuclear@2 1669 _tr_tally_lit(s, s->window[s->strstart-1], bflush);
nuclear@2 1670 s->match_available = 0;
nuclear@2 1671 }
nuclear@2 1672 FLUSH_BLOCK(s, flush == Z_FINISH);
nuclear@2 1673 return flush == Z_FINISH ? finish_done : block_done;
nuclear@2 1674 }
nuclear@2 1675 #endif /* FASTEST */
nuclear@2 1676
nuclear@2 1677 #if 0
nuclear@2 1678 /* ===========================================================================
nuclear@2 1679 * For Z_RLE, simply look for runs of bytes, generate matches only of distance
nuclear@2 1680 * one. Do not maintain a hash table. (It will be regenerated if this run of
nuclear@2 1681 * deflate switches away from Z_RLE.)
nuclear@2 1682 */
nuclear@2 1683 local block_state deflate_rle(s, flush)
nuclear@2 1684 deflate_state *s;
nuclear@2 1685 int flush;
nuclear@2 1686 {
nuclear@2 1687 int bflush; /* set if current block must be flushed */
nuclear@2 1688 uInt run; /* length of run */
nuclear@2 1689 uInt max; /* maximum length of run */
nuclear@2 1690 uInt prev; /* byte at distance one to match */
nuclear@2 1691 Bytef *scan; /* scan for end of run */
nuclear@2 1692
nuclear@2 1693 for (;;) {
nuclear@2 1694 /* Make sure that we always have enough lookahead, except
nuclear@2 1695 * at the end of the input file. We need MAX_MATCH bytes
nuclear@2 1696 * for the longest encodable run.
nuclear@2 1697 */
nuclear@2 1698 if (s->lookahead < MAX_MATCH) {
nuclear@2 1699 fill_window(s);
nuclear@2 1700 if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
nuclear@2 1701 return need_more;
nuclear@2 1702 }
nuclear@2 1703 if (s->lookahead == 0) break; /* flush the current block */
nuclear@2 1704 }
nuclear@2 1705
nuclear@2 1706 /* See how many times the previous byte repeats */
nuclear@2 1707 run = 0;
nuclear@2 1708 if (s->strstart > 0) { /* if there is a previous byte, that is */
nuclear@2 1709 max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH;
nuclear@2 1710 scan = s->window + s->strstart - 1;
nuclear@2 1711 prev = *scan++;
nuclear@2 1712 do {
nuclear@2 1713 if (*scan++ != prev)
nuclear@2 1714 break;
nuclear@2 1715 } while (++run < max);
nuclear@2 1716 }
nuclear@2 1717
nuclear@2 1718 /* Emit match if have run of MIN_MATCH or longer, else emit literal */
nuclear@2 1719 if (run >= MIN_MATCH) {
nuclear@2 1720 check_match(s, s->strstart, s->strstart - 1, run);
nuclear@2 1721 _tr_tally_dist(s, 1, run - MIN_MATCH, bflush);
nuclear@2 1722 s->lookahead -= run;
nuclear@2 1723 s->strstart += run;
nuclear@2 1724 } else {
nuclear@2 1725 /* No match, output a literal byte */
nuclear@2 1726 Tracevv((stderr,"%c", s->window[s->strstart]));
nuclear@2 1727 _tr_tally_lit (s, s->window[s->strstart], bflush);
nuclear@2 1728 s->lookahead--;
nuclear@2 1729 s->strstart++;
nuclear@2 1730 }
nuclear@2 1731 if (bflush) FLUSH_BLOCK(s, 0);
nuclear@2 1732 }
nuclear@2 1733 FLUSH_BLOCK(s, flush == Z_FINISH);
nuclear@2 1734 return flush == Z_FINISH ? finish_done : block_done;
nuclear@2 1735 }
nuclear@2 1736 #endif