lemon-project-template-glpk

annotate deps/glpk/src/zlib/deflate.c @ 9:33de93886c88

find changesets by author, revision, files, or words in the commit message
Import GLPK 4.47
author Alpar Juttner <alpar@cs.elte.hu>
date Sun, 06 Nov 2011 20:59:10 +0100
parents
children
rev   line source
alpar@9 1 /* deflate.c -- compress data using the deflation algorithm
alpar@9 2 * Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler
alpar@9 3 * For conditions of distribution and use, see copyright notice in zlib.h
alpar@9 4 */
alpar@9 5
alpar@9 6 /*
alpar@9 7 * ALGORITHM
alpar@9 8 *
alpar@9 9 * The "deflation" process depends on being able to identify portions
alpar@9 10 * of the input text which are identical to earlier input (within a
alpar@9 11 * sliding window trailing behind the input currently being processed).
alpar@9 12 *
alpar@9 13 * The most straightforward technique turns out to be the fastest for
alpar@9 14 * most input files: try all possible matches and select the longest.
alpar@9 15 * The key feature of this algorithm is that insertions into the string
alpar@9 16 * dictionary are very simple and thus fast, and deletions are avoided
alpar@9 17 * completely. Insertions are performed at each input character, whereas
alpar@9 18 * string matches are performed only when the previous match ends. So it
alpar@9 19 * is preferable to spend more time in matches to allow very fast string
alpar@9 20 * insertions and avoid deletions. The matching algorithm for small
alpar@9 21 * strings is inspired from that of Rabin & Karp. A brute force approach
alpar@9 22 * is used to find longer strings when a small match has been found.
alpar@9 23 * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
alpar@9 24 * (by Leonid Broukhis).
alpar@9 25 * A previous version of this file used a more sophisticated algorithm
alpar@9 26 * (by Fiala and Greene) which is guaranteed to run in linear amortized
alpar@9 27 * time, but has a larger average cost, uses more memory and is patented.
alpar@9 28 * However the F&G algorithm may be faster for some highly redundant
alpar@9 29 * files if the parameter max_chain_length (described below) is too large.
alpar@9 30 *
alpar@9 31 * ACKNOWLEDGEMENTS
alpar@9 32 *
alpar@9 33 * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
alpar@9 34 * I found it in 'freeze' written by Leonid Broukhis.
alpar@9 35 * Thanks to many people for bug reports and testing.
alpar@9 36 *
alpar@9 37 * REFERENCES
alpar@9 38 *
alpar@9 39 * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
alpar@9 40 * Available in http://www.ietf.org/rfc/rfc1951.txt
alpar@9 41 *
alpar@9 42 * A description of the Rabin and Karp algorithm is given in the book
alpar@9 43 * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
alpar@9 44 *
alpar@9 45 * Fiala,E.R., and Greene,D.H.
alpar@9 46 * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
alpar@9 47 *
alpar@9 48 */
alpar@9 49
alpar@9 50 /* @(#) $Id$ */
alpar@9 51
alpar@9 52 #include "deflate.h"
alpar@9 53
alpar@9 54 const char deflate_copyright[] =
alpar@9 55 " deflate 1.2.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler ";
alpar@9 56 /*
alpar@9 57 If you use the zlib library in a product, an acknowledgment is welcome
alpar@9 58 in the documentation of your product. If for some reason you cannot
alpar@9 59 include such an acknowledgment, I would appreciate that you keep this
alpar@9 60 copyright string in the executable of your product.
alpar@9 61 */
alpar@9 62
alpar@9 63 /* ===========================================================================
alpar@9 64 * Function prototypes.
alpar@9 65 */
alpar@9 66 typedef enum {
alpar@9 67 need_more, /* block not completed, need more input or more output */
alpar@9 68 block_done, /* block flush performed */
alpar@9 69 finish_started, /* finish started, need only more output at next deflate */
alpar@9 70 finish_done /* finish done, accept no more input or output */
alpar@9 71 } block_state;
alpar@9 72
alpar@9 73 typedef block_state (*compress_func) OF((deflate_state *s, int flush));
alpar@9 74 /* Compression function. Returns the block state after the call. */
alpar@9 75
alpar@9 76 local void fill_window OF((deflate_state *s));
alpar@9 77 local block_state deflate_stored OF((deflate_state *s, int flush));
alpar@9 78 local block_state deflate_fast OF((deflate_state *s, int flush));
alpar@9 79 #ifndef FASTEST
alpar@9 80 local block_state deflate_slow OF((deflate_state *s, int flush));
alpar@9 81 #endif
alpar@9 82 local block_state deflate_rle OF((deflate_state *s, int flush));
alpar@9 83 local block_state deflate_huff OF((deflate_state *s, int flush));
alpar@9 84 local void lm_init OF((deflate_state *s));
alpar@9 85 local void putShortMSB OF((deflate_state *s, uInt b));
alpar@9 86 local void flush_pending OF((z_streamp strm));
alpar@9 87 local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
alpar@9 88 #ifdef ASMV
alpar@9 89 void match_init OF((void)); /* asm code initialization */
alpar@9 90 uInt longest_match OF((deflate_state *s, IPos cur_match));
alpar@9 91 #else
alpar@9 92 local uInt longest_match OF((deflate_state *s, IPos cur_match));
alpar@9 93 #endif
alpar@9 94
alpar@9 95 #ifdef DEBUG
alpar@9 96 local void check_match OF((deflate_state *s, IPos start, IPos match,
alpar@9 97 int length));
alpar@9 98 #endif
alpar@9 99
alpar@9 100 /* ===========================================================================
alpar@9 101 * Local data
alpar@9 102 */
alpar@9 103
alpar@9 104 #define NIL 0
alpar@9 105 /* Tail of hash chains */
alpar@9 106
alpar@9 107 #ifndef TOO_FAR
alpar@9 108 # define TOO_FAR 4096
alpar@9 109 #endif
alpar@9 110 /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
alpar@9 111
alpar@9 112 /* Values for max_lazy_match, good_match and max_chain_length, depending on
alpar@9 113 * the desired pack level (0..9). The values given below have been tuned to
alpar@9 114 * exclude worst case performance for pathological files. Better values may be
alpar@9 115 * found for specific files.
alpar@9 116 */
alpar@9 117 typedef struct config_s {
alpar@9 118 ush good_length; /* reduce lazy search above this match length */
alpar@9 119 ush max_lazy; /* do not perform lazy search above this match length */
alpar@9 120 ush nice_length; /* quit search above this match length */
alpar@9 121 ush max_chain;
alpar@9 122 compress_func func;
alpar@9 123 } config;
alpar@9 124
alpar@9 125 #ifdef FASTEST
alpar@9 126 local const config configuration_table[2] = {
alpar@9 127 /* good lazy nice chain */
alpar@9 128 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
alpar@9 129 /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
alpar@9 130 #else
alpar@9 131 local const config configuration_table[10] = {
alpar@9 132 /* good lazy nice chain */
alpar@9 133 /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
alpar@9 134 /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
alpar@9 135 /* 2 */ {4, 5, 16, 8, deflate_fast},
alpar@9 136 /* 3 */ {4, 6, 32, 32, deflate_fast},
alpar@9 137
alpar@9 138 /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
alpar@9 139 /* 5 */ {8, 16, 32, 32, deflate_slow},
alpar@9 140 /* 6 */ {8, 16, 128, 128, deflate_slow},
alpar@9 141 /* 7 */ {8, 32, 128, 256, deflate_slow},
alpar@9 142 /* 8 */ {32, 128, 258, 1024, deflate_slow},
alpar@9 143 /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
alpar@9 144 #endif
alpar@9 145
alpar@9 146 /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
alpar@9 147 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
alpar@9 148 * meaning.
alpar@9 149 */
alpar@9 150
alpar@9 151 #define EQUAL 0
alpar@9 152 /* result of memcmp for equal strings */
alpar@9 153
alpar@9 154 #ifndef NO_DUMMY_DECL
alpar@9 155 struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
alpar@9 156 #endif
alpar@9 157
alpar@9 158 /* ===========================================================================
alpar@9 159 * Update a hash value with the given input byte
alpar@9 160 * IN assertion: all calls to to UPDATE_HASH are made with consecutive
alpar@9 161 * input characters, so that a running hash key can be computed from the
alpar@9 162 * previous key instead of complete recalculation each time.
alpar@9 163 */
alpar@9 164 #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
alpar@9 165
alpar@9 166
alpar@9 167 /* ===========================================================================
alpar@9 168 * Insert string str in the dictionary and set match_head to the previous head
alpar@9 169 * of the hash chain (the most recent string with same hash key). Return
alpar@9 170 * the previous length of the hash chain.
alpar@9 171 * If this file is compiled with -DFASTEST, the compression level is forced
alpar@9 172 * to 1, and no hash chains are maintained.
alpar@9 173 * IN assertion: all calls to to INSERT_STRING are made with consecutive
alpar@9 174 * input characters and the first MIN_MATCH bytes of str are valid
alpar@9 175 * (except for the last MIN_MATCH-1 bytes of the input file).
alpar@9 176 */
alpar@9 177 #ifdef FASTEST
alpar@9 178 #define INSERT_STRING(s, str, match_head) \
alpar@9 179 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
alpar@9 180 match_head = s->head[s->ins_h], \
alpar@9 181 s->head[s->ins_h] = (Pos)(str))
alpar@9 182 #else
alpar@9 183 #define INSERT_STRING(s, str, match_head) \
alpar@9 184 (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
alpar@9 185 match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
alpar@9 186 s->head[s->ins_h] = (Pos)(str))
alpar@9 187 #endif
alpar@9 188
alpar@9 189 /* ===========================================================================
alpar@9 190 * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
alpar@9 191 * prev[] will be initialized on the fly.
alpar@9 192 */
alpar@9 193 #define CLEAR_HASH(s) \
alpar@9 194 s->head[s->hash_size-1] = NIL; \
alpar@9 195 zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
alpar@9 196
alpar@9 197 /* ========================================================================= */
alpar@9 198 int ZEXPORT deflateInit_(strm, level, version, stream_size)
alpar@9 199 z_streamp strm;
alpar@9 200 int level;
alpar@9 201 const char *version;
alpar@9 202 int stream_size;
alpar@9 203 {
alpar@9 204 return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
alpar@9 205 Z_DEFAULT_STRATEGY, version, stream_size);
alpar@9 206 /* To do: ignore strm->next_in if we use it as window */
alpar@9 207 }
alpar@9 208
alpar@9 209 /* ========================================================================= */
alpar@9 210 int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
alpar@9 211 version, stream_size)
alpar@9 212 z_streamp strm;
alpar@9 213 int level;
alpar@9 214 int method;
alpar@9 215 int windowBits;
alpar@9 216 int memLevel;
alpar@9 217 int strategy;
alpar@9 218 const char *version;
alpar@9 219 int stream_size;
alpar@9 220 {
alpar@9 221 deflate_state *s;
alpar@9 222 int wrap = 1;
alpar@9 223 static const char my_version[] = ZLIB_VERSION;
alpar@9 224
alpar@9 225 ushf *overlay;
alpar@9 226 /* We overlay pending_buf and d_buf+l_buf. This works since the average
alpar@9 227 * output size for (length,distance) codes is <= 24 bits.
alpar@9 228 */
alpar@9 229
alpar@9 230 if (version == Z_NULL || version[0] != my_version[0] ||
alpar@9 231 stream_size != sizeof(z_stream)) {
alpar@9 232 return Z_VERSION_ERROR;
alpar@9 233 }
alpar@9 234 if (strm == Z_NULL) return Z_STREAM_ERROR;
alpar@9 235
alpar@9 236 strm->msg = Z_NULL;
alpar@9 237 if (strm->zalloc == (alloc_func)0) {
alpar@9 238 strm->zalloc = zcalloc;
alpar@9 239 strm->opaque = (voidpf)0;
alpar@9 240 }
alpar@9 241 if (strm->zfree == (free_func)0) strm->zfree = zcfree;
alpar@9 242
alpar@9 243 #ifdef FASTEST
alpar@9 244 if (level != 0) level = 1;
alpar@9 245 #else
alpar@9 246 if (level == Z_DEFAULT_COMPRESSION) level = 6;
alpar@9 247 #endif
alpar@9 248
alpar@9 249 if (windowBits < 0) { /* suppress zlib wrapper */
alpar@9 250 wrap = 0;
alpar@9 251 windowBits = -windowBits;
alpar@9 252 }
alpar@9 253 #ifdef GZIP
alpar@9 254 else if (windowBits > 15) {
alpar@9 255 wrap = 2; /* write gzip wrapper instead */
alpar@9 256 windowBits -= 16;
alpar@9 257 }
alpar@9 258 #endif
alpar@9 259 if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
alpar@9 260 windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
alpar@9 261 strategy < 0 || strategy > Z_FIXED) {
alpar@9 262 return Z_STREAM_ERROR;
alpar@9 263 }
alpar@9 264 if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
alpar@9 265 s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
alpar@9 266 if (s == Z_NULL) return Z_MEM_ERROR;
alpar@9 267 strm->state = (struct internal_state FAR *)s;
alpar@9 268 s->strm = strm;
alpar@9 269
alpar@9 270 s->wrap = wrap;
alpar@9 271 s->gzhead = Z_NULL;
alpar@9 272 s->w_bits = windowBits;
alpar@9 273 s->w_size = 1 << s->w_bits;
alpar@9 274 s->w_mask = s->w_size - 1;
alpar@9 275
alpar@9 276 s->hash_bits = memLevel + 7;
alpar@9 277 s->hash_size = 1 << s->hash_bits;
alpar@9 278 s->hash_mask = s->hash_size - 1;
alpar@9 279 s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
alpar@9 280
alpar@9 281 s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
alpar@9 282 s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
alpar@9 283 s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
alpar@9 284
alpar@9 285 s->high_water = 0; /* nothing written to s->window yet */
alpar@9 286
alpar@9 287 s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
alpar@9 288
alpar@9 289 overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
alpar@9 290 s->pending_buf = (uchf *) overlay;
alpar@9 291 s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
alpar@9 292
alpar@9 293 if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
alpar@9 294 s->pending_buf == Z_NULL) {
alpar@9 295 s->status = FINISH_STATE;
alpar@9 296 strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
alpar@9 297 deflateEnd (strm);
alpar@9 298 return Z_MEM_ERROR;
alpar@9 299 }
alpar@9 300 s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
alpar@9 301 s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
alpar@9 302
alpar@9 303 s->level = level;
alpar@9 304 s->strategy = strategy;
alpar@9 305 s->method = (Byte)method;
alpar@9 306
alpar@9 307 return deflateReset(strm);
alpar@9 308 }
alpar@9 309
alpar@9 310 /* ========================================================================= */
alpar@9 311 int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
alpar@9 312 z_streamp strm;
alpar@9 313 const Bytef *dictionary;
alpar@9 314 uInt dictLength;
alpar@9 315 {
alpar@9 316 deflate_state *s;
alpar@9 317 uInt length = dictLength;
alpar@9 318 uInt n;
alpar@9 319 IPos hash_head = 0;
alpar@9 320
alpar@9 321 if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
alpar@9 322 strm->state->wrap == 2 ||
alpar@9 323 (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
alpar@9 324 return Z_STREAM_ERROR;
alpar@9 325
alpar@9 326 s = strm->state;
alpar@9 327 if (s->wrap)
alpar@9 328 strm->adler = adler32(strm->adler, dictionary, dictLength);
alpar@9 329
alpar@9 330 if (length < MIN_MATCH) return Z_OK;
alpar@9 331 if (length > s->w_size) {
alpar@9 332 length = s->w_size;
alpar@9 333 dictionary += dictLength - length; /* use the tail of the dictionary */
alpar@9 334 }
alpar@9 335 zmemcpy(s->window, dictionary, length);
alpar@9 336 s->strstart = length;
alpar@9 337 s->block_start = (long)length;
alpar@9 338
alpar@9 339 /* Insert all strings in the hash table (except for the last two bytes).
alpar@9 340 * s->lookahead stays null, so s->ins_h will be recomputed at the next
alpar@9 341 * call of fill_window.
alpar@9 342 */
alpar@9 343 s->ins_h = s->window[0];
alpar@9 344 UPDATE_HASH(s, s->ins_h, s->window[1]);
alpar@9 345 for (n = 0; n <= length - MIN_MATCH; n++) {
alpar@9 346 INSERT_STRING(s, n, hash_head);
alpar@9 347 }
alpar@9 348 if (hash_head) hash_head = 0; /* to make compiler happy */
alpar@9 349 return Z_OK;
alpar@9 350 }
alpar@9 351
alpar@9 352 /* ========================================================================= */
alpar@9 353 int ZEXPORT deflateReset (strm)
alpar@9 354 z_streamp strm;
alpar@9 355 {
alpar@9 356 deflate_state *s;
alpar@9 357
alpar@9 358 if (strm == Z_NULL || strm->state == Z_NULL ||
alpar@9 359 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
alpar@9 360 return Z_STREAM_ERROR;
alpar@9 361 }
alpar@9 362
alpar@9 363 strm->total_in = strm->total_out = 0;
alpar@9 364 strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
alpar@9 365 strm->data_type = Z_UNKNOWN;
alpar@9 366
alpar@9 367 s = (deflate_state *)strm->state;
alpar@9 368 s->pending = 0;
alpar@9 369 s->pending_out = s->pending_buf;
alpar@9 370
alpar@9 371 if (s->wrap < 0) {
alpar@9 372 s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
alpar@9 373 }
alpar@9 374 s->status = s->wrap ? INIT_STATE : BUSY_STATE;
alpar@9 375 strm->adler =
alpar@9 376 #ifdef GZIP
alpar@9 377 s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
alpar@9 378 #endif
alpar@9 379 adler32(0L, Z_NULL, 0);
alpar@9 380 s->last_flush = Z_NO_FLUSH;
alpar@9 381
alpar@9 382 _tr_init(s);
alpar@9 383 lm_init(s);
alpar@9 384
alpar@9 385 return Z_OK;
alpar@9 386 }
alpar@9 387
alpar@9 388 /* ========================================================================= */
alpar@9 389 int ZEXPORT deflateSetHeader (strm, head)
alpar@9 390 z_streamp strm;
alpar@9 391 gz_headerp head;
alpar@9 392 {
alpar@9 393 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
alpar@9 394 if (strm->state->wrap != 2) return Z_STREAM_ERROR;
alpar@9 395 strm->state->gzhead = head;
alpar@9 396 return Z_OK;
alpar@9 397 }
alpar@9 398
alpar@9 399 /* ========================================================================= */
alpar@9 400 int ZEXPORT deflatePrime (strm, bits, value)
alpar@9 401 z_streamp strm;
alpar@9 402 int bits;
alpar@9 403 int value;
alpar@9 404 {
alpar@9 405 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
alpar@9 406 strm->state->bi_valid = bits;
alpar@9 407 strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
alpar@9 408 return Z_OK;
alpar@9 409 }
alpar@9 410
alpar@9 411 /* ========================================================================= */
alpar@9 412 int ZEXPORT deflateParams(strm, level, strategy)
alpar@9 413 z_streamp strm;
alpar@9 414 int level;
alpar@9 415 int strategy;
alpar@9 416 {
alpar@9 417 deflate_state *s;
alpar@9 418 compress_func func;
alpar@9 419 int err = Z_OK;
alpar@9 420
alpar@9 421 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
alpar@9 422 s = strm->state;
alpar@9 423
alpar@9 424 #ifdef FASTEST
alpar@9 425 if (level != 0) level = 1;
alpar@9 426 #else
alpar@9 427 if (level == Z_DEFAULT_COMPRESSION) level = 6;
alpar@9 428 #endif
alpar@9 429 if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
alpar@9 430 return Z_STREAM_ERROR;
alpar@9 431 }
alpar@9 432 func = configuration_table[s->level].func;
alpar@9 433
alpar@9 434 if ((strategy != s->strategy || func != configuration_table[level].func) &&
alpar@9 435 strm->total_in != 0) {
alpar@9 436 /* Flush the last buffer: */
alpar@9 437 err = deflate(strm, Z_BLOCK);
alpar@9 438 }
alpar@9 439 if (s->level != level) {
alpar@9 440 s->level = level;
alpar@9 441 s->max_lazy_match = configuration_table[level].max_lazy;
alpar@9 442 s->good_match = configuration_table[level].good_length;
alpar@9 443 s->nice_match = configuration_table[level].nice_length;
alpar@9 444 s->max_chain_length = configuration_table[level].max_chain;
alpar@9 445 }
alpar@9 446 s->strategy = strategy;
alpar@9 447 return err;
alpar@9 448 }
alpar@9 449
alpar@9 450 /* ========================================================================= */
alpar@9 451 int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
alpar@9 452 z_streamp strm;
alpar@9 453 int good_length;
alpar@9 454 int max_lazy;
alpar@9 455 int nice_length;
alpar@9 456 int max_chain;
alpar@9 457 {
alpar@9 458 deflate_state *s;
alpar@9 459
alpar@9 460 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
alpar@9 461 s = strm->state;
alpar@9 462 s->good_match = good_length;
alpar@9 463 s->max_lazy_match = max_lazy;
alpar@9 464 s->nice_match = nice_length;
alpar@9 465 s->max_chain_length = max_chain;
alpar@9 466 return Z_OK;
alpar@9 467 }
alpar@9 468
alpar@9 469 /* =========================================================================
alpar@9 470 * For the default windowBits of 15 and memLevel of 8, this function returns
alpar@9 471 * a close to exact, as well as small, upper bound on the compressed size.
alpar@9 472 * They are coded as constants here for a reason--if the #define's are
alpar@9 473 * changed, then this function needs to be changed as well. The return
alpar@9 474 * value for 15 and 8 only works for those exact settings.
alpar@9 475 *
alpar@9 476 * For any setting other than those defaults for windowBits and memLevel,
alpar@9 477 * the value returned is a conservative worst case for the maximum expansion
alpar@9 478 * resulting from using fixed blocks instead of stored blocks, which deflate
alpar@9 479 * can emit on compressed data for some combinations of the parameters.
alpar@9 480 *
alpar@9 481 * This function could be more sophisticated to provide closer upper bounds for
alpar@9 482 * every combination of windowBits and memLevel. But even the conservative
alpar@9 483 * upper bound of about 14% expansion does not seem onerous for output buffer
alpar@9 484 * allocation.
alpar@9 485 */
alpar@9 486 uLong ZEXPORT deflateBound(strm, sourceLen)
alpar@9 487 z_streamp strm;
alpar@9 488 uLong sourceLen;
alpar@9 489 {
alpar@9 490 deflate_state *s;
alpar@9 491 uLong complen, wraplen;
alpar@9 492 Bytef *str;
alpar@9 493
alpar@9 494 /* conservative upper bound for compressed data */
alpar@9 495 complen = sourceLen +
alpar@9 496 ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
alpar@9 497
alpar@9 498 /* if can't get parameters, return conservative bound plus zlib wrapper */
alpar@9 499 if (strm == Z_NULL || strm->state == Z_NULL)
alpar@9 500 return complen + 6;
alpar@9 501
alpar@9 502 /* compute wrapper length */
alpar@9 503 s = strm->state;
alpar@9 504 switch (s->wrap) {
alpar@9 505 case 0: /* raw deflate */
alpar@9 506 wraplen = 0;
alpar@9 507 break;
alpar@9 508 case 1: /* zlib wrapper */
alpar@9 509 wraplen = 6 + (s->strstart ? 4 : 0);
alpar@9 510 break;
alpar@9 511 case 2: /* gzip wrapper */
alpar@9 512 wraplen = 18;
alpar@9 513 if (s->gzhead != Z_NULL) { /* user-supplied gzip header */
alpar@9 514 if (s->gzhead->extra != Z_NULL)
alpar@9 515 wraplen += 2 + s->gzhead->extra_len;
alpar@9 516 str = s->gzhead->name;
alpar@9 517 if (str != Z_NULL)
alpar@9 518 do {
alpar@9 519 wraplen++;
alpar@9 520 } while (*str++);
alpar@9 521 str = s->gzhead->comment;
alpar@9 522 if (str != Z_NULL)
alpar@9 523 do {
alpar@9 524 wraplen++;
alpar@9 525 } while (*str++);
alpar@9 526 if (s->gzhead->hcrc)
alpar@9 527 wraplen += 2;
alpar@9 528 }
alpar@9 529 break;
alpar@9 530 default: /* for compiler happiness */
alpar@9 531 wraplen = 6;
alpar@9 532 }
alpar@9 533
alpar@9 534 /* if not default parameters, return conservative bound */
alpar@9 535 if (s->w_bits != 15 || s->hash_bits != 8 + 7)
alpar@9 536 return complen + wraplen;
alpar@9 537
alpar@9 538 /* default settings: return tight bound for that case */
alpar@9 539 return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
alpar@9 540 (sourceLen >> 25) + 13 - 6 + wraplen;
alpar@9 541 }
alpar@9 542
alpar@9 543 /* =========================================================================
alpar@9 544 * Put a short in the pending buffer. The 16-bit value is put in MSB order.
alpar@9 545 * IN assertion: the stream state is correct and there is enough room in
alpar@9 546 * pending_buf.
alpar@9 547 */
alpar@9 548 local void putShortMSB (s, b)
alpar@9 549 deflate_state *s;
alpar@9 550 uInt b;
alpar@9 551 {
alpar@9 552 put_byte(s, (Byte)(b >> 8));
alpar@9 553 put_byte(s, (Byte)(b & 0xff));
alpar@9 554 }
alpar@9 555
alpar@9 556 /* =========================================================================
alpar@9 557 * Flush as much pending output as possible. All deflate() output goes
alpar@9 558 * through this function so some applications may wish to modify it
alpar@9 559 * to avoid allocating a large strm->next_out buffer and copying into it.
alpar@9 560 * (See also read_buf()).
alpar@9 561 */
alpar@9 562 local void flush_pending(strm)
alpar@9 563 z_streamp strm;
alpar@9 564 {
alpar@9 565 unsigned len = strm->state->pending;
alpar@9 566
alpar@9 567 if (len > strm->avail_out) len = strm->avail_out;
alpar@9 568 if (len == 0) return;
alpar@9 569
alpar@9 570 zmemcpy(strm->next_out, strm->state->pending_out, len);
alpar@9 571 strm->next_out += len;
alpar@9 572 strm->state->pending_out += len;
alpar@9 573 strm->total_out += len;
alpar@9 574 strm->avail_out -= len;
alpar@9 575 strm->state->pending -= len;
alpar@9 576 if (strm->state->pending == 0) {
alpar@9 577 strm->state->pending_out = strm->state->pending_buf;
alpar@9 578 }
alpar@9 579 }
alpar@9 580
alpar@9 581 /* ========================================================================= */
alpar@9 582 int ZEXPORT deflate (strm, flush)
alpar@9 583 z_streamp strm;
alpar@9 584 int flush;
alpar@9 585 {
alpar@9 586 int old_flush; /* value of flush param for previous deflate call */
alpar@9 587 deflate_state *s;
alpar@9 588
alpar@9 589 if (strm == Z_NULL || strm->state == Z_NULL ||
alpar@9 590 flush > Z_BLOCK || flush < 0) {
alpar@9 591 return Z_STREAM_ERROR;
alpar@9 592 }
alpar@9 593 s = strm->state;
alpar@9 594
alpar@9 595 if (strm->next_out == Z_NULL ||
alpar@9 596 (strm->next_in == Z_NULL && strm->avail_in != 0) ||
alpar@9 597 (s->status == FINISH_STATE && flush != Z_FINISH)) {
alpar@9 598 ERR_RETURN(strm, Z_STREAM_ERROR);
alpar@9 599 }
alpar@9 600 if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
alpar@9 601
alpar@9 602 s->strm = strm; /* just in case */
alpar@9 603 old_flush = s->last_flush;
alpar@9 604 s->last_flush = flush;
alpar@9 605
alpar@9 606 /* Write the header */
alpar@9 607 if (s->status == INIT_STATE) {
alpar@9 608 #ifdef GZIP
alpar@9 609 if (s->wrap == 2) {
alpar@9 610 strm->adler = crc32(0L, Z_NULL, 0);
alpar@9 611 put_byte(s, 31);
alpar@9 612 put_byte(s, 139);
alpar@9 613 put_byte(s, 8);
alpar@9 614 if (s->gzhead == Z_NULL) {
alpar@9 615 put_byte(s, 0);
alpar@9 616 put_byte(s, 0);
alpar@9 617 put_byte(s, 0);
alpar@9 618 put_byte(s, 0);
alpar@9 619 put_byte(s, 0);
alpar@9 620 put_byte(s, s->level == 9 ? 2 :
alpar@9 621 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
alpar@9 622 4 : 0));
alpar@9 623 put_byte(s, OS_CODE);
alpar@9 624 s->status = BUSY_STATE;
alpar@9 625 }
alpar@9 626 else {
alpar@9 627 put_byte(s, (s->gzhead->text ? 1 : 0) +
alpar@9 628 (s->gzhead->hcrc ? 2 : 0) +
alpar@9 629 (s->gzhead->extra == Z_NULL ? 0 : 4) +
alpar@9 630 (s->gzhead->name == Z_NULL ? 0 : 8) +
alpar@9 631 (s->gzhead->comment == Z_NULL ? 0 : 16)
alpar@9 632 );
alpar@9 633 put_byte(s, (Byte)(s->gzhead->time & 0xff));
alpar@9 634 put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
alpar@9 635 put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
alpar@9 636 put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
alpar@9 637 put_byte(s, s->level == 9 ? 2 :
alpar@9 638 (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
alpar@9 639 4 : 0));
alpar@9 640 put_byte(s, s->gzhead->os & 0xff);
alpar@9 641 if (s->gzhead->extra != Z_NULL) {
alpar@9 642 put_byte(s, s->gzhead->extra_len & 0xff);
alpar@9 643 put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
alpar@9 644 }
alpar@9 645 if (s->gzhead->hcrc)
alpar@9 646 strm->adler = crc32(strm->adler, s->pending_buf,
alpar@9 647 s->pending);
alpar@9 648 s->gzindex = 0;
alpar@9 649 s->status = EXTRA_STATE;
alpar@9 650 }
alpar@9 651 }
alpar@9 652 else
alpar@9 653 #endif
alpar@9 654 {
alpar@9 655 uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
alpar@9 656 uInt level_flags;
alpar@9 657
alpar@9 658 if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
alpar@9 659 level_flags = 0;
alpar@9 660 else if (s->level < 6)
alpar@9 661 level_flags = 1;
alpar@9 662 else if (s->level == 6)
alpar@9 663 level_flags = 2;
alpar@9 664 else
alpar@9 665 level_flags = 3;
alpar@9 666 header |= (level_flags << 6);
alpar@9 667 if (s->strstart != 0) header |= PRESET_DICT;
alpar@9 668 header += 31 - (header % 31);
alpar@9 669
alpar@9 670 s->status = BUSY_STATE;
alpar@9 671 putShortMSB(s, header);
alpar@9 672
alpar@9 673 /* Save the adler32 of the preset dictionary: */
alpar@9 674 if (s->strstart != 0) {
alpar@9 675 putShortMSB(s, (uInt)(strm->adler >> 16));
alpar@9 676 putShortMSB(s, (uInt)(strm->adler & 0xffff));
alpar@9 677 }
alpar@9 678 strm->adler = adler32(0L, Z_NULL, 0);
alpar@9 679 }
alpar@9 680 }
alpar@9 681 #ifdef GZIP
alpar@9 682 if (s->status == EXTRA_STATE) {
alpar@9 683 if (s->gzhead->extra != Z_NULL) {
alpar@9 684 uInt beg = s->pending; /* start of bytes to update crc */
alpar@9 685
alpar@9 686 while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
alpar@9 687 if (s->pending == s->pending_buf_size) {
alpar@9 688 if (s->gzhead->hcrc && s->pending > beg)
alpar@9 689 strm->adler = crc32(strm->adler, s->pending_buf + beg,
alpar@9 690 s->pending - beg);
alpar@9 691 flush_pending(strm);
alpar@9 692 beg = s->pending;
alpar@9 693 if (s->pending == s->pending_buf_size)
alpar@9 694 break;
alpar@9 695 }
alpar@9 696 put_byte(s, s->gzhead->extra[s->gzindex]);
alpar@9 697 s->gzindex++;
alpar@9 698 }
alpar@9 699 if (s->gzhead->hcrc && s->pending > beg)
alpar@9 700 strm->adler = crc32(strm->adler, s->pending_buf + beg,
alpar@9 701 s->pending - beg);
alpar@9 702 if (s->gzindex == s->gzhead->extra_len) {
alpar@9 703 s->gzindex = 0;
alpar@9 704 s->status = NAME_STATE;
alpar@9 705 }
alpar@9 706 }
alpar@9 707 else
alpar@9 708 s->status = NAME_STATE;
alpar@9 709 }
alpar@9 710 if (s->status == NAME_STATE) {
alpar@9 711 if (s->gzhead->name != Z_NULL) {
alpar@9 712 uInt beg = s->pending; /* start of bytes to update crc */
alpar@9 713 int val;
alpar@9 714
alpar@9 715 do {
alpar@9 716 if (s->pending == s->pending_buf_size) {
alpar@9 717 if (s->gzhead->hcrc && s->pending > beg)
alpar@9 718 strm->adler = crc32(strm->adler, s->pending_buf + beg,
alpar@9 719 s->pending - beg);
alpar@9 720 flush_pending(strm);
alpar@9 721 beg = s->pending;
alpar@9 722 if (s->pending == s->pending_buf_size) {
alpar@9 723 val = 1;
alpar@9 724 break;
alpar@9 725 }
alpar@9 726 }
alpar@9 727 val = s->gzhead->name[s->gzindex++];
alpar@9 728 put_byte(s, val);
alpar@9 729 } while (val != 0);
alpar@9 730 if (s->gzhead->hcrc && s->pending > beg)
alpar@9 731 strm->adler = crc32(strm->adler, s->pending_buf + beg,
alpar@9 732 s->pending - beg);
alpar@9 733 if (val == 0) {
alpar@9 734 s->gzindex = 0;
alpar@9 735 s->status = COMMENT_STATE;
alpar@9 736 }
alpar@9 737 }
alpar@9 738 else
alpar@9 739 s->status = COMMENT_STATE;
alpar@9 740 }
alpar@9 741 if (s->status == COMMENT_STATE) {
alpar@9 742 if (s->gzhead->comment != Z_NULL) {
alpar@9 743 uInt beg = s->pending; /* start of bytes to update crc */
alpar@9 744 int val;
alpar@9 745
alpar@9 746 do {
alpar@9 747 if (s->pending == s->pending_buf_size) {
alpar@9 748 if (s->gzhead->hcrc && s->pending > beg)
alpar@9 749 strm->adler = crc32(strm->adler, s->pending_buf + beg,
alpar@9 750 s->pending - beg);
alpar@9 751 flush_pending(strm);
alpar@9 752 beg = s->pending;
alpar@9 753 if (s->pending == s->pending_buf_size) {
alpar@9 754 val = 1;
alpar@9 755 break;
alpar@9 756 }
alpar@9 757 }
alpar@9 758 val = s->gzhead->comment[s->gzindex++];
alpar@9 759 put_byte(s, val);
alpar@9 760 } while (val != 0);
alpar@9 761 if (s->gzhead->hcrc && s->pending > beg)
alpar@9 762 strm->adler = crc32(strm->adler, s->pending_buf + beg,
alpar@9 763 s->pending - beg);
alpar@9 764 if (val == 0)
alpar@9 765 s->status = HCRC_STATE;
alpar@9 766 }
alpar@9 767 else
alpar@9 768 s->status = HCRC_STATE;
alpar@9 769 }
alpar@9 770 if (s->status == HCRC_STATE) {
alpar@9 771 if (s->gzhead->hcrc) {
alpar@9 772 if (s->pending + 2 > s->pending_buf_size)
alpar@9 773 flush_pending(strm);
alpar@9 774 if (s->pending + 2 <= s->pending_buf_size) {
alpar@9 775 put_byte(s, (Byte)(strm->adler & 0xff));
alpar@9 776 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
alpar@9 777 strm->adler = crc32(0L, Z_NULL, 0);
alpar@9 778 s->status = BUSY_STATE;
alpar@9 779 }
alpar@9 780 }
alpar@9 781 else
alpar@9 782 s->status = BUSY_STATE;
alpar@9 783 }
alpar@9 784 #endif
alpar@9 785
alpar@9 786 /* Flush as much pending output as possible */
alpar@9 787 if (s->pending != 0) {
alpar@9 788 flush_pending(strm);
alpar@9 789 if (strm->avail_out == 0) {
alpar@9 790 /* Since avail_out is 0, deflate will be called again with
alpar@9 791 * more output space, but possibly with both pending and
alpar@9 792 * avail_in equal to zero. There won't be anything to do,
alpar@9 793 * but this is not an error situation so make sure we
alpar@9 794 * return OK instead of BUF_ERROR at next call of deflate:
alpar@9 795 */
alpar@9 796 s->last_flush = -1;
alpar@9 797 return Z_OK;
alpar@9 798 }
alpar@9 799
alpar@9 800 /* Make sure there is something to do and avoid duplicate consecutive
alpar@9 801 * flushes. For repeated and useless calls with Z_FINISH, we keep
alpar@9 802 * returning Z_STREAM_END instead of Z_BUF_ERROR.
alpar@9 803 */
alpar@9 804 } else if (strm->avail_in == 0 && flush <= old_flush &&
alpar@9 805 flush != Z_FINISH) {
alpar@9 806 ERR_RETURN(strm, Z_BUF_ERROR);
alpar@9 807 }
alpar@9 808
alpar@9 809 /* User must not provide more input after the first FINISH: */
alpar@9 810 if (s->status == FINISH_STATE && strm->avail_in != 0) {
alpar@9 811 ERR_RETURN(strm, Z_BUF_ERROR);
alpar@9 812 }
alpar@9 813
alpar@9 814 /* Start a new block or continue the current one.
alpar@9 815 */
alpar@9 816 if (strm->avail_in != 0 || s->lookahead != 0 ||
alpar@9 817 (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
alpar@9 818 block_state bstate;
alpar@9 819
alpar@9 820 bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
alpar@9 821 (s->strategy == Z_RLE ? deflate_rle(s, flush) :
alpar@9 822 (*(configuration_table[s->level].func))(s, flush));
alpar@9 823
alpar@9 824 if (bstate == finish_started || bstate == finish_done) {
alpar@9 825 s->status = FINISH_STATE;
alpar@9 826 }
alpar@9 827 if (bstate == need_more || bstate == finish_started) {
alpar@9 828 if (strm->avail_out == 0) {
alpar@9 829 s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
alpar@9 830 }
alpar@9 831 return Z_OK;
alpar@9 832 /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
alpar@9 833 * of deflate should use the same flush parameter to make sure
alpar@9 834 * that the flush is complete. So we don't have to output an
alpar@9 835 * empty block here, this will be done at next call. This also
alpar@9 836 * ensures that for a very small output buffer, we emit at most
alpar@9 837 * one empty block.
alpar@9 838 */
alpar@9 839 }
alpar@9 840 if (bstate == block_done) {
alpar@9 841 if (flush == Z_PARTIAL_FLUSH) {
alpar@9 842 _tr_align(s);
alpar@9 843 } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
alpar@9 844 _tr_stored_block(s, (char*)0, 0L, 0);
alpar@9 845 /* For a full flush, this empty block will be recognized
alpar@9 846 * as a special marker by inflate_sync().
alpar@9 847 */
alpar@9 848 if (flush == Z_FULL_FLUSH) {
alpar@9 849 CLEAR_HASH(s); /* forget history */
alpar@9 850 if (s->lookahead == 0) {
alpar@9 851 s->strstart = 0;
alpar@9 852 s->block_start = 0L;
alpar@9 853 }
alpar@9 854 }
alpar@9 855 }
alpar@9 856 flush_pending(strm);
alpar@9 857 if (strm->avail_out == 0) {
alpar@9 858 s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
alpar@9 859 return Z_OK;
alpar@9 860 }
alpar@9 861 }
alpar@9 862 }
alpar@9 863 Assert(strm->avail_out > 0, "bug2");
alpar@9 864
alpar@9 865 if (flush != Z_FINISH) return Z_OK;
alpar@9 866 if (s->wrap <= 0) return Z_STREAM_END;
alpar@9 867
alpar@9 868 /* Write the trailer */
alpar@9 869 #ifdef GZIP
alpar@9 870 if (s->wrap == 2) {
alpar@9 871 put_byte(s, (Byte)(strm->adler & 0xff));
alpar@9 872 put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
alpar@9 873 put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
alpar@9 874 put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
alpar@9 875 put_byte(s, (Byte)(strm->total_in & 0xff));
alpar@9 876 put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
alpar@9 877 put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
alpar@9 878 put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
alpar@9 879 }
alpar@9 880 else
alpar@9 881 #endif
alpar@9 882 {
alpar@9 883 putShortMSB(s, (uInt)(strm->adler >> 16));
alpar@9 884 putShortMSB(s, (uInt)(strm->adler & 0xffff));
alpar@9 885 }
alpar@9 886 flush_pending(strm);
alpar@9 887 /* If avail_out is zero, the application will call deflate again
alpar@9 888 * to flush the rest.
alpar@9 889 */
alpar@9 890 if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
alpar@9 891 return s->pending != 0 ? Z_OK : Z_STREAM_END;
alpar@9 892 }
alpar@9 893
alpar@9 894 /* ========================================================================= */
alpar@9 895 int ZEXPORT deflateEnd (strm)
alpar@9 896 z_streamp strm;
alpar@9 897 {
alpar@9 898 int status;
alpar@9 899
alpar@9 900 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
alpar@9 901
alpar@9 902 status = strm->state->status;
alpar@9 903 if (status != INIT_STATE &&
alpar@9 904 status != EXTRA_STATE &&
alpar@9 905 status != NAME_STATE &&
alpar@9 906 status != COMMENT_STATE &&
alpar@9 907 status != HCRC_STATE &&
alpar@9 908 status != BUSY_STATE &&
alpar@9 909 status != FINISH_STATE) {
alpar@9 910 return Z_STREAM_ERROR;
alpar@9 911 }
alpar@9 912
alpar@9 913 /* Deallocate in reverse order of allocations: */
alpar@9 914 TRY_FREE(strm, strm->state->pending_buf);
alpar@9 915 TRY_FREE(strm, strm->state->head);
alpar@9 916 TRY_FREE(strm, strm->state->prev);
alpar@9 917 TRY_FREE(strm, strm->state->window);
alpar@9 918
alpar@9 919 ZFREE(strm, strm->state);
alpar@9 920 strm->state = Z_NULL;
alpar@9 921
alpar@9 922 return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
alpar@9 923 }
alpar@9 924
alpar@9 925 /* =========================================================================
alpar@9 926 * Copy the source state to the destination state.
alpar@9 927 * To simplify the source, this is not supported for 16-bit MSDOS (which
alpar@9 928 * doesn't have enough memory anyway to duplicate compression states).
alpar@9 929 */
alpar@9 930 int ZEXPORT deflateCopy (dest, source)
alpar@9 931 z_streamp dest;
alpar@9 932 z_streamp source;
alpar@9 933 {
alpar@9 934 #ifdef MAXSEG_64K
alpar@9 935 return Z_STREAM_ERROR;
alpar@9 936 #else
alpar@9 937 deflate_state *ds;
alpar@9 938 deflate_state *ss;
alpar@9 939 ushf *overlay;
alpar@9 940
alpar@9 941
alpar@9 942 if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
alpar@9 943 return Z_STREAM_ERROR;
alpar@9 944 }
alpar@9 945
alpar@9 946 ss = source->state;
alpar@9 947
alpar@9 948 zmemcpy(dest, source, sizeof(z_stream));
alpar@9 949
alpar@9 950 ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
alpar@9 951 if (ds == Z_NULL) return Z_MEM_ERROR;
alpar@9 952 dest->state = (struct internal_state FAR *) ds;
alpar@9 953 zmemcpy(ds, ss, sizeof(deflate_state));
alpar@9 954 ds->strm = dest;
alpar@9 955
alpar@9 956 ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
alpar@9 957 ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
alpar@9 958 ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
alpar@9 959 overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
alpar@9 960 ds->pending_buf = (uchf *) overlay;
alpar@9 961
alpar@9 962 if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
alpar@9 963 ds->pending_buf == Z_NULL) {
alpar@9 964 deflateEnd (dest);
alpar@9 965 return Z_MEM_ERROR;
alpar@9 966 }
alpar@9 967 /* following zmemcpy do not work for 16-bit MSDOS */
alpar@9 968 zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
alpar@9 969 zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
alpar@9 970 zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
alpar@9 971 zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
alpar@9 972
alpar@9 973 ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
alpar@9 974 ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
alpar@9 975 ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
alpar@9 976
alpar@9 977 ds->l_desc.dyn_tree = ds->dyn_ltree;
alpar@9 978 ds->d_desc.dyn_tree = ds->dyn_dtree;
alpar@9 979 ds->bl_desc.dyn_tree = ds->bl_tree;
alpar@9 980
alpar@9 981 return Z_OK;
alpar@9 982 #endif /* MAXSEG_64K */
alpar@9 983 }
alpar@9 984
alpar@9 985 /* ===========================================================================
alpar@9 986 * Read a new buffer from the current input stream, update the adler32
alpar@9 987 * and total number of bytes read. All deflate() input goes through
alpar@9 988 * this function so some applications may wish to modify it to avoid
alpar@9 989 * allocating a large strm->next_in buffer and copying from it.
alpar@9 990 * (See also flush_pending()).
alpar@9 991 */
alpar@9 992 local int read_buf(strm, buf, size)
alpar@9 993 z_streamp strm;
alpar@9 994 Bytef *buf;
alpar@9 995 unsigned size;
alpar@9 996 {
alpar@9 997 unsigned len = strm->avail_in;
alpar@9 998
alpar@9 999 if (len > size) len = size;
alpar@9 1000 if (len == 0) return 0;
alpar@9 1001
alpar@9 1002 strm->avail_in -= len;
alpar@9 1003
alpar@9 1004 if (strm->state->wrap == 1) {
alpar@9 1005 strm->adler = adler32(strm->adler, strm->next_in, len);
alpar@9 1006 }
alpar@9 1007 #ifdef GZIP
alpar@9 1008 else if (strm->state->wrap == 2) {
alpar@9 1009 strm->adler = crc32(strm->adler, strm->next_in, len);
alpar@9 1010 }
alpar@9 1011 #endif
alpar@9 1012 zmemcpy(buf, strm->next_in, len);
alpar@9 1013 strm->next_in += len;
alpar@9 1014 strm->total_in += len;
alpar@9 1015
alpar@9 1016 return (int)len;
alpar@9 1017 }
alpar@9 1018
alpar@9 1019 /* ===========================================================================
alpar@9 1020 * Initialize the "longest match" routines for a new zlib stream
alpar@9 1021 */
alpar@9 1022 local void lm_init (s)
alpar@9 1023 deflate_state *s;
alpar@9 1024 {
alpar@9 1025 s->window_size = (ulg)2L*s->w_size;
alpar@9 1026
alpar@9 1027 CLEAR_HASH(s);
alpar@9 1028
alpar@9 1029 /* Set the default configuration parameters:
alpar@9 1030 */
alpar@9 1031 s->max_lazy_match = configuration_table[s->level].max_lazy;
alpar@9 1032 s->good_match = configuration_table[s->level].good_length;
alpar@9 1033 s->nice_match = configuration_table[s->level].nice_length;
alpar@9 1034 s->max_chain_length = configuration_table[s->level].max_chain;
alpar@9 1035
alpar@9 1036 s->strstart = 0;
alpar@9 1037 s->block_start = 0L;
alpar@9 1038 s->lookahead = 0;
alpar@9 1039 s->match_length = s->prev_length = MIN_MATCH-1;
alpar@9 1040 s->match_available = 0;
alpar@9 1041 s->ins_h = 0;
alpar@9 1042 #ifndef FASTEST
alpar@9 1043 #ifdef ASMV
alpar@9 1044 match_init(); /* initialize the asm code */
alpar@9 1045 #endif
alpar@9 1046 #endif
alpar@9 1047 }
alpar@9 1048
alpar@9 1049 #ifndef FASTEST
alpar@9 1050 /* ===========================================================================
alpar@9 1051 * Set match_start to the longest match starting at the given string and
alpar@9 1052 * return its length. Matches shorter or equal to prev_length are discarded,
alpar@9 1053 * in which case the result is equal to prev_length and match_start is
alpar@9 1054 * garbage.
alpar@9 1055 * IN assertions: cur_match is the head of the hash chain for the current
alpar@9 1056 * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
alpar@9 1057 * OUT assertion: the match length is not greater than s->lookahead.
alpar@9 1058 */
alpar@9 1059 #ifndef ASMV
alpar@9 1060 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
alpar@9 1061 * match.S. The code will be functionally equivalent.
alpar@9 1062 */
alpar@9 1063 local uInt longest_match(s, cur_match)
alpar@9 1064 deflate_state *s;
alpar@9 1065 IPos cur_match; /* current match */
alpar@9 1066 {
alpar@9 1067 unsigned chain_length = s->max_chain_length;/* max hash chain length */
alpar@9 1068 register Bytef *scan = s->window + s->strstart; /* current string */
alpar@9 1069 register Bytef *match; /* matched string */
alpar@9 1070 register int len; /* length of current match */
alpar@9 1071 int best_len = s->prev_length; /* best match length so far */
alpar@9 1072 int nice_match = s->nice_match; /* stop if match long enough */
alpar@9 1073 IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
alpar@9 1074 s->strstart - (IPos)MAX_DIST(s) : NIL;
alpar@9 1075 /* Stop when cur_match becomes <= limit. To simplify the code,
alpar@9 1076 * we prevent matches with the string of window index 0.
alpar@9 1077 */
alpar@9 1078 Posf *prev = s->prev;
alpar@9 1079 uInt wmask = s->w_mask;
alpar@9 1080
alpar@9 1081 #ifdef UNALIGNED_OK
alpar@9 1082 /* Compare two bytes at a time. Note: this is not always beneficial.
alpar@9 1083 * Try with and without -DUNALIGNED_OK to check.
alpar@9 1084 */
alpar@9 1085 register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
alpar@9 1086 register ush scan_start = *(ushf*)scan;
alpar@9 1087 register ush scan_end = *(ushf*)(scan+best_len-1);
alpar@9 1088 #else
alpar@9 1089 register Bytef *strend = s->window + s->strstart + MAX_MATCH;
alpar@9 1090 register Byte scan_end1 = scan[best_len-1];
alpar@9 1091 register Byte scan_end = scan[best_len];
alpar@9 1092 #endif
alpar@9 1093
alpar@9 1094 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
alpar@9 1095 * It is easy to get rid of this optimization if necessary.
alpar@9 1096 */
alpar@9 1097 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
alpar@9 1098
alpar@9 1099 /* Do not waste too much time if we already have a good match: */
alpar@9 1100 if (s->prev_length >= s->good_match) {
alpar@9 1101 chain_length >>= 2;
alpar@9 1102 }
alpar@9 1103 /* Do not look for matches beyond the end of the input. This is necessary
alpar@9 1104 * to make deflate deterministic.
alpar@9 1105 */
alpar@9 1106 if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
alpar@9 1107
alpar@9 1108 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
alpar@9 1109
alpar@9 1110 do {
alpar@9 1111 Assert(cur_match < s->strstart, "no future");
alpar@9 1112 match = s->window + cur_match;
alpar@9 1113
alpar@9 1114 /* Skip to next match if the match length cannot increase
alpar@9 1115 * or if the match length is less than 2. Note that the checks below
alpar@9 1116 * for insufficient lookahead only occur occasionally for performance
alpar@9 1117 * reasons. Therefore uninitialized memory will be accessed, and
alpar@9 1118 * conditional jumps will be made that depend on those values.
alpar@9 1119 * However the length of the match is limited to the lookahead, so
alpar@9 1120 * the output of deflate is not affected by the uninitialized values.
alpar@9 1121 */
alpar@9 1122 #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
alpar@9 1123 /* This code assumes sizeof(unsigned short) == 2. Do not use
alpar@9 1124 * UNALIGNED_OK if your compiler uses a different size.
alpar@9 1125 */
alpar@9 1126 if (*(ushf*)(match+best_len-1) != scan_end ||
alpar@9 1127 *(ushf*)match != scan_start) continue;
alpar@9 1128
alpar@9 1129 /* It is not necessary to compare scan[2] and match[2] since they are
alpar@9 1130 * always equal when the other bytes match, given that the hash keys
alpar@9 1131 * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
alpar@9 1132 * strstart+3, +5, ... up to strstart+257. We check for insufficient
alpar@9 1133 * lookahead only every 4th comparison; the 128th check will be made
alpar@9 1134 * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
alpar@9 1135 * necessary to put more guard bytes at the end of the window, or
alpar@9 1136 * to check more often for insufficient lookahead.
alpar@9 1137 */
alpar@9 1138 Assert(scan[2] == match[2], "scan[2]?");
alpar@9 1139 scan++, match++;
alpar@9 1140 do {
alpar@9 1141 } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
alpar@9 1142 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
alpar@9 1143 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
alpar@9 1144 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
alpar@9 1145 scan < strend);
alpar@9 1146 /* The funny "do {}" generates better code on most compilers */
alpar@9 1147
alpar@9 1148 /* Here, scan <= window+strstart+257 */
alpar@9 1149 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
alpar@9 1150 if (*scan == *match) scan++;
alpar@9 1151
alpar@9 1152 len = (MAX_MATCH - 1) - (int)(strend-scan);
alpar@9 1153 scan = strend - (MAX_MATCH-1);
alpar@9 1154
alpar@9 1155 #else /* UNALIGNED_OK */
alpar@9 1156
alpar@9 1157 if (match[best_len] != scan_end ||
alpar@9 1158 match[best_len-1] != scan_end1 ||
alpar@9 1159 *match != *scan ||
alpar@9 1160 *++match != scan[1]) continue;
alpar@9 1161
alpar@9 1162 /* The check at best_len-1 can be removed because it will be made
alpar@9 1163 * again later. (This heuristic is not always a win.)
alpar@9 1164 * It is not necessary to compare scan[2] and match[2] since they
alpar@9 1165 * are always equal when the other bytes match, given that
alpar@9 1166 * the hash keys are equal and that HASH_BITS >= 8.
alpar@9 1167 */
alpar@9 1168 scan += 2, match++;
alpar@9 1169 Assert(*scan == *match, "match[2]?");
alpar@9 1170
alpar@9 1171 /* We check for insufficient lookahead only every 8th comparison;
alpar@9 1172 * the 256th check will be made at strstart+258.
alpar@9 1173 */
alpar@9 1174 do {
alpar@9 1175 } while (*++scan == *++match && *++scan == *++match &&
alpar@9 1176 *++scan == *++match && *++scan == *++match &&
alpar@9 1177 *++scan == *++match && *++scan == *++match &&
alpar@9 1178 *++scan == *++match && *++scan == *++match &&
alpar@9 1179 scan < strend);
alpar@9 1180
alpar@9 1181 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
alpar@9 1182
alpar@9 1183 len = MAX_MATCH - (int)(strend - scan);
alpar@9 1184 scan = strend - MAX_MATCH;
alpar@9 1185
alpar@9 1186 #endif /* UNALIGNED_OK */
alpar@9 1187
alpar@9 1188 if (len > best_len) {
alpar@9 1189 s->match_start = cur_match;
alpar@9 1190 best_len = len;
alpar@9 1191 if (len >= nice_match) break;
alpar@9 1192 #ifdef UNALIGNED_OK
alpar@9 1193 scan_end = *(ushf*)(scan+best_len-1);
alpar@9 1194 #else
alpar@9 1195 scan_end1 = scan[best_len-1];
alpar@9 1196 scan_end = scan[best_len];
alpar@9 1197 #endif
alpar@9 1198 }
alpar@9 1199 } while ((cur_match = prev[cur_match & wmask]) > limit
alpar@9 1200 && --chain_length != 0);
alpar@9 1201
alpar@9 1202 if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
alpar@9 1203 return s->lookahead;
alpar@9 1204 }
alpar@9 1205 #endif /* ASMV */
alpar@9 1206
alpar@9 1207 #else /* FASTEST */
alpar@9 1208
alpar@9 1209 /* ---------------------------------------------------------------------------
alpar@9 1210 * Optimized version for FASTEST only
alpar@9 1211 */
alpar@9 1212 local uInt longest_match(s, cur_match)
alpar@9 1213 deflate_state *s;
alpar@9 1214 IPos cur_match; /* current match */
alpar@9 1215 {
alpar@9 1216 register Bytef *scan = s->window + s->strstart; /* current string */
alpar@9 1217 register Bytef *match; /* matched string */
alpar@9 1218 register int len; /* length of current match */
alpar@9 1219 register Bytef *strend = s->window + s->strstart + MAX_MATCH;
alpar@9 1220
alpar@9 1221 /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
alpar@9 1222 * It is easy to get rid of this optimization if necessary.
alpar@9 1223 */
alpar@9 1224 Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
alpar@9 1225
alpar@9 1226 Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
alpar@9 1227
alpar@9 1228 Assert(cur_match < s->strstart, "no future");
alpar@9 1229
alpar@9 1230 match = s->window + cur_match;
alpar@9 1231
alpar@9 1232 /* Return failure if the match length is less than 2:
alpar@9 1233 */
alpar@9 1234 if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
alpar@9 1235
alpar@9 1236 /* The check at best_len-1 can be removed because it will be made
alpar@9 1237 * again later. (This heuristic is not always a win.)
alpar@9 1238 * It is not necessary to compare scan[2] and match[2] since they
alpar@9 1239 * are always equal when the other bytes match, given that
alpar@9 1240 * the hash keys are equal and that HASH_BITS >= 8.
alpar@9 1241 */
alpar@9 1242 scan += 2, match += 2;
alpar@9 1243 Assert(*scan == *match, "match[2]?");
alpar@9 1244
alpar@9 1245 /* We check for insufficient lookahead only every 8th comparison;
alpar@9 1246 * the 256th check will be made at strstart+258.
alpar@9 1247 */
alpar@9 1248 do {
alpar@9 1249 } while (*++scan == *++match && *++scan == *++match &&
alpar@9 1250 *++scan == *++match && *++scan == *++match &&
alpar@9 1251 *++scan == *++match && *++scan == *++match &&
alpar@9 1252 *++scan == *++match && *++scan == *++match &&
alpar@9 1253 scan < strend);
alpar@9 1254
alpar@9 1255 Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
alpar@9 1256
alpar@9 1257 len = MAX_MATCH - (int)(strend - scan);
alpar@9 1258
alpar@9 1259 if (len < MIN_MATCH) return MIN_MATCH - 1;
alpar@9 1260
alpar@9 1261 s->match_start = cur_match;
alpar@9 1262 return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
alpar@9 1263 }
alpar@9 1264
alpar@9 1265 #endif /* FASTEST */
alpar@9 1266
alpar@9 1267 #ifdef DEBUG
alpar@9 1268 /* ===========================================================================
alpar@9 1269 * Check that the match at match_start is indeed a match.
alpar@9 1270 */
alpar@9 1271 local void check_match(s, start, match, length)
alpar@9 1272 deflate_state *s;
alpar@9 1273 IPos start, match;
alpar@9 1274 int length;
alpar@9 1275 {
alpar@9 1276 /* check that the match is indeed a match */
alpar@9 1277 if (zmemcmp(s->window + match,
alpar@9 1278 s->window + start, length) != EQUAL) {
alpar@9 1279 fprintf(stderr, " start %u, match %u, length %d\n",
alpar@9 1280 start, match, length);
alpar@9 1281 do {
alpar@9 1282 fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
alpar@9 1283 } while (--length != 0);
alpar@9 1284 z_error("invalid match");
alpar@9 1285 }
alpar@9 1286 if (z_verbose > 1) {
alpar@9 1287 fprintf(stderr,"\\[%d,%d]", start-match, length);
alpar@9 1288 do { putc(s->window[start++], stderr); } while (--length != 0);
alpar@9 1289 }
alpar@9 1290 }
alpar@9 1291 #else
alpar@9 1292 # define check_match(s, start, match, length)
alpar@9 1293 #endif /* DEBUG */
alpar@9 1294
alpar@9 1295 /* ===========================================================================
alpar@9 1296 * Fill the window when the lookahead becomes insufficient.
alpar@9 1297 * Updates strstart and lookahead.
alpar@9 1298 *
alpar@9 1299 * IN assertion: lookahead < MIN_LOOKAHEAD
alpar@9 1300 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
alpar@9 1301 * At least one byte has been read, or avail_in == 0; reads are
alpar@9 1302 * performed for at least two bytes (required for the zip translate_eol
alpar@9 1303 * option -- not supported here).
alpar@9 1304 */
alpar@9 1305 local void fill_window(s)
alpar@9 1306 deflate_state *s;
alpar@9 1307 {
alpar@9 1308 register unsigned n, m;
alpar@9 1309 register Posf *p;
alpar@9 1310 unsigned more; /* Amount of free space at the end of the window. */
alpar@9 1311 uInt wsize = s->w_size;
alpar@9 1312
alpar@9 1313 do {
alpar@9 1314 more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
alpar@9 1315
alpar@9 1316 /* Deal with !@#$% 64K limit: */
alpar@9 1317 if (sizeof(int) <= 2) {
alpar@9 1318 if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
alpar@9 1319 more = wsize;
alpar@9 1320
alpar@9 1321 } else if (more == (unsigned)(-1)) {
alpar@9 1322 /* Very unlikely, but possible on 16 bit machine if
alpar@9 1323 * strstart == 0 && lookahead == 1 (input done a byte at time)
alpar@9 1324 */
alpar@9 1325 more--;
alpar@9 1326 }
alpar@9 1327 }
alpar@9 1328
alpar@9 1329 /* If the window is almost full and there is insufficient lookahead,
alpar@9 1330 * move the upper half to the lower one to make room in the upper half.
alpar@9 1331 */
alpar@9 1332 if (s->strstart >= wsize+MAX_DIST(s)) {
alpar@9 1333
alpar@9 1334 zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
alpar@9 1335 s->match_start -= wsize;
alpar@9 1336 s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
alpar@9 1337 s->block_start -= (long) wsize;
alpar@9 1338
alpar@9 1339 /* Slide the hash table (could be avoided with 32 bit values
alpar@9 1340 at the expense of memory usage). We slide even when level == 0
alpar@9 1341 to keep the hash table consistent if we switch back to level > 0
alpar@9 1342 later. (Using level 0 permanently is not an optimal usage of
alpar@9 1343 zlib, so we don't care about this pathological case.)
alpar@9 1344 */
alpar@9 1345 n = s->hash_size;
alpar@9 1346 p = &s->head[n];
alpar@9 1347 do {
alpar@9 1348 m = *--p;
alpar@9 1349 *p = (Pos)(m >= wsize ? m-wsize : NIL);
alpar@9 1350 } while (--n);
alpar@9 1351
alpar@9 1352 n = wsize;
alpar@9 1353 #ifndef FASTEST
alpar@9 1354 p = &s->prev[n];
alpar@9 1355 do {
alpar@9 1356 m = *--p;
alpar@9 1357 *p = (Pos)(m >= wsize ? m-wsize : NIL);
alpar@9 1358 /* If n is not on any hash chain, prev[n] is garbage but
alpar@9 1359 * its value will never be used.
alpar@9 1360 */
alpar@9 1361 } while (--n);
alpar@9 1362 #endif
alpar@9 1363 more += wsize;
alpar@9 1364 }
alpar@9 1365 if (s->strm->avail_in == 0) return;
alpar@9 1366
alpar@9 1367 /* If there was no sliding:
alpar@9 1368 * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
alpar@9 1369 * more == window_size - lookahead - strstart
alpar@9 1370 * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
alpar@9 1371 * => more >= window_size - 2*WSIZE + 2
alpar@9 1372 * In the BIG_MEM or MMAP case (not yet supported),
alpar@9 1373 * window_size == input_size + MIN_LOOKAHEAD &&
alpar@9 1374 * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
alpar@9 1375 * Otherwise, window_size == 2*WSIZE so more >= 2.
alpar@9 1376 * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
alpar@9 1377 */
alpar@9 1378 Assert(more >= 2, "more < 2");
alpar@9 1379
alpar@9 1380 n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
alpar@9 1381 s->lookahead += n;
alpar@9 1382
alpar@9 1383 /* Initialize the hash value now that we have some input: */
alpar@9 1384 if (s->lookahead >= MIN_MATCH) {
alpar@9 1385 s->ins_h = s->window[s->strstart];
alpar@9 1386 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
alpar@9 1387 #if MIN_MATCH != 3
alpar@9 1388 Call UPDATE_HASH() MIN_MATCH-3 more times
alpar@9 1389 #endif
alpar@9 1390 }
alpar@9 1391 /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
alpar@9 1392 * but this is not important since only literal bytes will be emitted.
alpar@9 1393 */
alpar@9 1394
alpar@9 1395 } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
alpar@9 1396
alpar@9 1397 /* If the WIN_INIT bytes after the end of the current data have never been
alpar@9 1398 * written, then zero those bytes in order to avoid memory check reports of
alpar@9 1399 * the use of uninitialized (or uninitialised as Julian writes) bytes by
alpar@9 1400 * the longest match routines. Update the high water mark for the next
alpar@9 1401 * time through here. WIN_INIT is set to MAX_MATCH since the longest match
alpar@9 1402 * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
alpar@9 1403 */
alpar@9 1404 if (s->high_water < s->window_size) {
alpar@9 1405 ulg curr = s->strstart + (ulg)(s->lookahead);
alpar@9 1406 ulg init;
alpar@9 1407
alpar@9 1408 if (s->high_water < curr) {
alpar@9 1409 /* Previous high water mark below current data -- zero WIN_INIT
alpar@9 1410 * bytes or up to end of window, whichever is less.
alpar@9 1411 */
alpar@9 1412 init = s->window_size - curr;
alpar@9 1413 if (init > WIN_INIT)
alpar@9 1414 init = WIN_INIT;
alpar@9 1415 zmemzero(s->window + curr, (unsigned)init);
alpar@9 1416 s->high_water = curr + init;
alpar@9 1417 }
alpar@9 1418 else if (s->high_water < (ulg)curr + WIN_INIT) {
alpar@9 1419 /* High water mark at or above current data, but below current data
alpar@9 1420 * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
alpar@9 1421 * to end of window, whichever is less.
alpar@9 1422 */
alpar@9 1423 init = (ulg)curr + WIN_INIT - s->high_water;
alpar@9 1424 if (init > s->window_size - s->high_water)
alpar@9 1425 init = s->window_size - s->high_water;
alpar@9 1426 zmemzero(s->window + s->high_water, (unsigned)init);
alpar@9 1427 s->high_water += init;
alpar@9 1428 }
alpar@9 1429 }
alpar@9 1430 }
alpar@9 1431
alpar@9 1432 /* ===========================================================================
alpar@9 1433 * Flush the current block, with given end-of-file flag.
alpar@9 1434 * IN assertion: strstart is set to the end of the current match.
alpar@9 1435 */
alpar@9 1436 #define FLUSH_BLOCK_ONLY(s, last) { \
alpar@9 1437 _tr_flush_block(s, (s->block_start >= 0L ? \
alpar@9 1438 (charf *)&s->window[(unsigned)s->block_start] : \
alpar@9 1439 (charf *)Z_NULL), \
alpar@9 1440 (ulg)((long)s->strstart - s->block_start), \
alpar@9 1441 (last)); \
alpar@9 1442 s->block_start = s->strstart; \
alpar@9 1443 flush_pending(s->strm); \
alpar@9 1444 Tracev((stderr,"[FLUSH]")); \
alpar@9 1445 }
alpar@9 1446
alpar@9 1447 /* Same but force premature exit if necessary. */
alpar@9 1448 #define FLUSH_BLOCK(s, last) { \
alpar@9 1449 FLUSH_BLOCK_ONLY(s, last); \
alpar@9 1450 if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
alpar@9 1451 }
alpar@9 1452
alpar@9 1453 /* ===========================================================================
alpar@9 1454 * Copy without compression as much as possible from the input stream, return
alpar@9 1455 * the current block state.
alpar@9 1456 * This function does not insert new strings in the dictionary since
alpar@9 1457 * uncompressible data is probably not useful. This function is used
alpar@9 1458 * only for the level=0 compression option.
alpar@9 1459 * NOTE: this function should be optimized to avoid extra copying from
alpar@9 1460 * window to pending_buf.
alpar@9 1461 */
alpar@9 1462 local block_state deflate_stored(s, flush)
alpar@9 1463 deflate_state *s;
alpar@9 1464 int flush;
alpar@9 1465 {
alpar@9 1466 /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
alpar@9 1467 * to pending_buf_size, and each stored block has a 5 byte header:
alpar@9 1468 */
alpar@9 1469 ulg max_block_size = 0xffff;
alpar@9 1470 ulg max_start;
alpar@9 1471
alpar@9 1472 if (max_block_size > s->pending_buf_size - 5) {
alpar@9 1473 max_block_size = s->pending_buf_size - 5;
alpar@9 1474 }
alpar@9 1475
alpar@9 1476 /* Copy as much as possible from input to output: */
alpar@9 1477 for (;;) {
alpar@9 1478 /* Fill the window as much as possible: */
alpar@9 1479 if (s->lookahead <= 1) {
alpar@9 1480
alpar@9 1481 Assert(s->strstart < s->w_size+MAX_DIST(s) ||
alpar@9 1482 s->block_start >= (long)s->w_size, "slide too late");
alpar@9 1483
alpar@9 1484 fill_window(s);
alpar@9 1485 if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
alpar@9 1486
alpar@9 1487 if (s->lookahead == 0) break; /* flush the current block */
alpar@9 1488 }
alpar@9 1489 Assert(s->block_start >= 0L, "block gone");
alpar@9 1490
alpar@9 1491 s->strstart += s->lookahead;
alpar@9 1492 s->lookahead = 0;
alpar@9 1493
alpar@9 1494 /* Emit a stored block if pending_buf will be full: */
alpar@9 1495 max_start = s->block_start + max_block_size;
alpar@9 1496 if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
alpar@9 1497 /* strstart == 0 is possible when wraparound on 16-bit machine */
alpar@9 1498 s->lookahead = (uInt)(s->strstart - max_start);
alpar@9 1499 s->strstart = (uInt)max_start;
alpar@9 1500 FLUSH_BLOCK(s, 0);
alpar@9 1501 }
alpar@9 1502 /* Flush if we may have to slide, otherwise block_start may become
alpar@9 1503 * negative and the data will be gone:
alpar@9 1504 */
alpar@9 1505 if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
alpar@9 1506 FLUSH_BLOCK(s, 0);
alpar@9 1507 }
alpar@9 1508 }
alpar@9 1509 FLUSH_BLOCK(s, flush == Z_FINISH);
alpar@9 1510 return flush == Z_FINISH ? finish_done : block_done;
alpar@9 1511 }
alpar@9 1512
alpar@9 1513 /* ===========================================================================
alpar@9 1514 * Compress as much as possible from the input stream, return the current
alpar@9 1515 * block state.
alpar@9 1516 * This function does not perform lazy evaluation of matches and inserts
alpar@9 1517 * new strings in the dictionary only for unmatched strings or for short
alpar@9 1518 * matches. It is used only for the fast compression options.
alpar@9 1519 */
alpar@9 1520 local block_state deflate_fast(s, flush)
alpar@9 1521 deflate_state *s;
alpar@9 1522 int flush;
alpar@9 1523 {
alpar@9 1524 IPos hash_head; /* head of the hash chain */
alpar@9 1525 int bflush; /* set if current block must be flushed */
alpar@9 1526
alpar@9 1527 for (;;) {
alpar@9 1528 /* Make sure that we always have enough lookahead, except
alpar@9 1529 * at the end of the input file. We need MAX_MATCH bytes
alpar@9 1530 * for the next match, plus MIN_MATCH bytes to insert the
alpar@9 1531 * string following the next match.
alpar@9 1532 */
alpar@9 1533 if (s->lookahead < MIN_LOOKAHEAD) {
alpar@9 1534 fill_window(s);
alpar@9 1535 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
alpar@9 1536 return need_more;
alpar@9 1537 }
alpar@9 1538 if (s->lookahead == 0) break; /* flush the current block */
alpar@9 1539 }
alpar@9 1540
alpar@9 1541 /* Insert the string window[strstart .. strstart+2] in the
alpar@9 1542 * dictionary, and set hash_head to the head of the hash chain:
alpar@9 1543 */
alpar@9 1544 hash_head = NIL;
alpar@9 1545 if (s->lookahead >= MIN_MATCH) {
alpar@9 1546 INSERT_STRING(s, s->strstart, hash_head);
alpar@9 1547 }
alpar@9 1548
alpar@9 1549 /* Find the longest match, discarding those <= prev_length.
alpar@9 1550 * At this point we have always match_length < MIN_MATCH
alpar@9 1551 */
alpar@9 1552 if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
alpar@9 1553 /* To simplify the code, we prevent matches with the string
alpar@9 1554 * of window index 0 (in particular we have to avoid a match
alpar@9 1555 * of the string with itself at the start of the input file).
alpar@9 1556 */
alpar@9 1557 s->match_length = longest_match (s, hash_head);
alpar@9 1558 /* longest_match() sets match_start */
alpar@9 1559 }
alpar@9 1560 if (s->match_length >= MIN_MATCH) {
alpar@9 1561 check_match(s, s->strstart, s->match_start, s->match_length);
alpar@9 1562
alpar@9 1563 _tr_tally_dist(s, s->strstart - s->match_start,
alpar@9 1564 s->match_length - MIN_MATCH, bflush);
alpar@9 1565
alpar@9 1566 s->lookahead -= s->match_length;
alpar@9 1567
alpar@9 1568 /* Insert new strings in the hash table only if the match length
alpar@9 1569 * is not too large. This saves time but degrades compression.
alpar@9 1570 */
alpar@9 1571 #ifndef FASTEST
alpar@9 1572 if (s->match_length <= s->max_insert_length &&
alpar@9 1573 s->lookahead >= MIN_MATCH) {
alpar@9 1574 s->match_length--; /* string at strstart already in table */
alpar@9 1575 do {
alpar@9 1576 s->strstart++;
alpar@9 1577 INSERT_STRING(s, s->strstart, hash_head);
alpar@9 1578 /* strstart never exceeds WSIZE-MAX_MATCH, so there are
alpar@9 1579 * always MIN_MATCH bytes ahead.
alpar@9 1580 */
alpar@9 1581 } while (--s->match_length != 0);
alpar@9 1582 s->strstart++;
alpar@9 1583 } else
alpar@9 1584 #endif
alpar@9 1585 {
alpar@9 1586 s->strstart += s->match_length;
alpar@9 1587 s->match_length = 0;
alpar@9 1588 s->ins_h = s->window[s->strstart];
alpar@9 1589 UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
alpar@9 1590 #if MIN_MATCH != 3
alpar@9 1591 Call UPDATE_HASH() MIN_MATCH-3 more times
alpar@9 1592 #endif
alpar@9 1593 /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
alpar@9 1594 * matter since it will be recomputed at next deflate call.
alpar@9 1595 */
alpar@9 1596 }
alpar@9 1597 } else {
alpar@9 1598 /* No match, output a literal byte */
alpar@9 1599 Tracevv((stderr,"%c", s->window[s->strstart]));
alpar@9 1600 _tr_tally_lit (s, s->window[s->strstart], bflush);
alpar@9 1601 s->lookahead--;
alpar@9 1602 s->strstart++;
alpar@9 1603 }
alpar@9 1604 if (bflush) FLUSH_BLOCK(s, 0);
alpar@9 1605 }
alpar@9 1606 FLUSH_BLOCK(s, flush == Z_FINISH);
alpar@9 1607 return flush == Z_FINISH ? finish_done : block_done;
alpar@9 1608 }
alpar@9 1609
alpar@9 1610 #ifndef FASTEST
alpar@9 1611 /* ===========================================================================
alpar@9 1612 * Same as above, but achieves better compression. We use a lazy
alpar@9 1613 * evaluation for matches: a match is finally adopted only if there is
alpar@9 1614 * no better match at the next window position.
alpar@9 1615 */
alpar@9 1616 local block_state deflate_slow(s, flush)
alpar@9 1617 deflate_state *s;
alpar@9 1618 int flush;
alpar@9 1619 {
alpar@9 1620 IPos hash_head; /* head of hash chain */
alpar@9 1621 int bflush; /* set if current block must be flushed */
alpar@9 1622
alpar@9 1623 /* Process the input block. */
alpar@9 1624 for (;;) {
alpar@9 1625 /* Make sure that we always have enough lookahead, except
alpar@9 1626 * at the end of the input file. We need MAX_MATCH bytes
alpar@9 1627 * for the next match, plus MIN_MATCH bytes to insert the
alpar@9 1628 * string following the next match.
alpar@9 1629 */
alpar@9 1630 if (s->lookahead < MIN_LOOKAHEAD) {
alpar@9 1631 fill_window(s);
alpar@9 1632 if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
alpar@9 1633 return need_more;
alpar@9 1634 }
alpar@9 1635 if (s->lookahead == 0) break; /* flush the current block */
alpar@9 1636 }
alpar@9 1637
alpar@9 1638 /* Insert the string window[strstart .. strstart+2] in the
alpar@9 1639 * dictionary, and set hash_head to the head of the hash chain:
alpar@9 1640 */
alpar@9 1641 hash_head = NIL;
alpar@9 1642 if (s->lookahead >= MIN_MATCH) {
alpar@9 1643 INSERT_STRING(s, s->strstart, hash_head);
alpar@9 1644 }
alpar@9 1645
alpar@9 1646 /* Find the longest match, discarding those <= prev_length.
alpar@9 1647 */
alpar@9 1648 s->prev_length = s->match_length, s->prev_match = s->match_start;
alpar@9 1649 s->match_length = MIN_MATCH-1;
alpar@9 1650
alpar@9 1651 if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
alpar@9 1652 s->strstart - hash_head <= MAX_DIST(s)) {
alpar@9 1653 /* To simplify the code, we prevent matches with the string
alpar@9 1654 * of window index 0 (in particular we have to avoid a match
alpar@9 1655 * of the string with itself at the start of the input file).
alpar@9 1656 */
alpar@9 1657 s->match_length = longest_match (s, hash_head);
alpar@9 1658 /* longest_match() sets match_start */
alpar@9 1659
alpar@9 1660 if (s->match_length <= 5 && (s->strategy == Z_FILTERED
alpar@9 1661 #if TOO_FAR <= 32767
alpar@9 1662 || (s->match_length == MIN_MATCH &&
alpar@9 1663 s->strstart - s->match_start > TOO_FAR)
alpar@9 1664 #endif
alpar@9 1665 )) {
alpar@9 1666
alpar@9 1667 /* If prev_match is also MIN_MATCH, match_start is garbage
alpar@9 1668 * but we will ignore the current match anyway.
alpar@9 1669 */
alpar@9 1670 s->match_length = MIN_MATCH-1;
alpar@9 1671 }
alpar@9 1672 }
alpar@9 1673 /* If there was a match at the previous step and the current
alpar@9 1674 * match is not better, output the previous match:
alpar@9 1675 */
alpar@9 1676 if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
alpar@9 1677 uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
alpar@9 1678 /* Do not insert strings in hash table beyond this. */
alpar@9 1679
alpar@9 1680 check_match(s, s->strstart-1, s->prev_match, s->prev_length);
alpar@9 1681
alpar@9 1682 _tr_tally_dist(s, s->strstart -1 - s->prev_match,
alpar@9 1683 s->prev_length - MIN_MATCH, bflush);
alpar@9 1684
alpar@9 1685 /* Insert in hash table all strings up to the end of the match.
alpar@9 1686 * strstart-1 and strstart are already inserted. If there is not
alpar@9 1687 * enough lookahead, the last two strings are not inserted in
alpar@9 1688 * the hash table.
alpar@9 1689 */
alpar@9 1690 s->lookahead -= s->prev_length-1;
alpar@9 1691 s->prev_length -= 2;
alpar@9 1692 do {
alpar@9 1693 if (++s->strstart <= max_insert) {
alpar@9 1694 INSERT_STRING(s, s->strstart, hash_head);
alpar@9 1695 }
alpar@9 1696 } while (--s->prev_length != 0);
alpar@9 1697 s->match_available = 0;
alpar@9 1698 s->match_length = MIN_MATCH-1;
alpar@9 1699 s->strstart++;
alpar@9 1700
alpar@9 1701 if (bflush) FLUSH_BLOCK(s, 0);
alpar@9 1702
alpar@9 1703 } else if (s->match_available) {
alpar@9 1704 /* If there was no match at the previous position, output a
alpar@9 1705 * single literal. If there was a match but the current match
alpar@9 1706 * is longer, truncate the previous match to a single literal.
alpar@9 1707 */
alpar@9 1708 Tracevv((stderr,"%c", s->window[s->strstart-1]));
alpar@9 1709 _tr_tally_lit(s, s->window[s->strstart-1], bflush);
alpar@9 1710 if (bflush) {
alpar@9 1711 FLUSH_BLOCK_ONLY(s, 0);
alpar@9 1712 }
alpar@9 1713 s->strstart++;
alpar@9 1714 s->lookahead--;
alpar@9 1715 if (s->strm->avail_out == 0) return need_more;
alpar@9 1716 } else {
alpar@9 1717 /* There is no previous match to compare with, wait for
alpar@9 1718 * the next step to decide.
alpar@9 1719 */
alpar@9 1720 s->match_available = 1;
alpar@9 1721 s->strstart++;
alpar@9 1722 s->lookahead--;
alpar@9 1723 }
alpar@9 1724 }
alpar@9 1725 Assert (flush != Z_NO_FLUSH, "no flush?");
alpar@9 1726 if (s->match_available) {
alpar@9 1727 Tracevv((stderr,"%c", s->window[s->strstart-1]));
alpar@9 1728 _tr_tally_lit(s, s->window[s->strstart-1], bflush);
alpar@9 1729 s->match_available = 0;
alpar@9 1730 }
alpar@9 1731 FLUSH_BLOCK(s, flush == Z_FINISH);
alpar@9 1732 return flush == Z_FINISH ? finish_done : block_done;
alpar@9 1733 }
alpar@9 1734 #endif /* FASTEST */
alpar@9 1735
alpar@9 1736 /* ===========================================================================
alpar@9 1737 * For Z_RLE, simply look for runs of bytes, generate matches only of distance
alpar@9 1738 * one. Do not maintain a hash table. (It will be regenerated if this run of
alpar@9 1739 * deflate switches away from Z_RLE.)
alpar@9 1740 */
alpar@9 1741 local block_state deflate_rle(s, flush)
alpar@9 1742 deflate_state *s;
alpar@9 1743 int flush;
alpar@9 1744 {
alpar@9 1745 int bflush; /* set if current block must be flushed */
alpar@9 1746 uInt prev; /* byte at distance one to match */
alpar@9 1747 Bytef *scan, *strend; /* scan goes up to strend for length of run */
alpar@9 1748
alpar@9 1749 for (;;) {
alpar@9 1750 /* Make sure that we always have enough lookahead, except
alpar@9 1751 * at the end of the input file. We need MAX_MATCH bytes
alpar@9 1752 * for the longest encodable run.
alpar@9 1753 */
alpar@9 1754 if (s->lookahead < MAX_MATCH) {
alpar@9 1755 fill_window(s);
alpar@9 1756 if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
alpar@9 1757 return need_more;
alpar@9 1758 }
alpar@9 1759 if (s->lookahead == 0) break; /* flush the current block */
alpar@9 1760 }
alpar@9 1761
alpar@9 1762 /* See how many times the previous byte repeats */
alpar@9 1763 s->match_length = 0;
alpar@9 1764 if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
alpar@9 1765 scan = s->window + s->strstart - 1;
alpar@9 1766 prev = *scan;
alpar@9 1767 if (prev == *++scan && prev == *++scan && prev == *++scan) {
alpar@9 1768 strend = s->window + s->strstart + MAX_MATCH;
alpar@9 1769 do {
alpar@9 1770 } while (prev == *++scan && prev == *++scan &&
alpar@9 1771 prev == *++scan && prev == *++scan &&
alpar@9 1772 prev == *++scan && prev == *++scan &&
alpar@9 1773 prev == *++scan && prev == *++scan &&
alpar@9 1774 scan < strend);
alpar@9 1775 s->match_length = MAX_MATCH - (int)(strend - scan);
alpar@9 1776 if (s->match_length > s->lookahead)
alpar@9 1777 s->match_length = s->lookahead;
alpar@9 1778 }
alpar@9 1779 }
alpar@9 1780
alpar@9 1781 /* Emit match if have run of MIN_MATCH or longer, else emit literal */
alpar@9 1782 if (s->match_length >= MIN_MATCH) {
alpar@9 1783 check_match(s, s->strstart, s->strstart - 1, s->match_length);
alpar@9 1784
alpar@9 1785 _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
alpar@9 1786
alpar@9 1787 s->lookahead -= s->match_length;
alpar@9 1788 s->strstart += s->match_length;
alpar@9 1789 s->match_length = 0;
alpar@9 1790 } else {
alpar@9 1791 /* No match, output a literal byte */
alpar@9 1792 Tracevv((stderr,"%c", s->window[s->strstart]));
alpar@9 1793 _tr_tally_lit (s, s->window[s->strstart], bflush);
alpar@9 1794 s->lookahead--;
alpar@9 1795 s->strstart++;
alpar@9 1796 }
alpar@9 1797 if (bflush) FLUSH_BLOCK(s, 0);
alpar@9 1798 }
alpar@9 1799 FLUSH_BLOCK(s, flush == Z_FINISH);
alpar@9 1800 return flush == Z_FINISH ? finish_done : block_done;
alpar@9 1801 }
alpar@9 1802
alpar@9 1803 /* ===========================================================================
alpar@9 1804 * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
alpar@9 1805 * (It will be regenerated if this run of deflate switches away from Huffman.)
alpar@9 1806 */
alpar@9 1807 local block_state deflate_huff(s, flush)
alpar@9 1808 deflate_state *s;
alpar@9 1809 int flush;
alpar@9 1810 {
alpar@9 1811 int bflush; /* set if current block must be flushed */
alpar@9 1812
alpar@9 1813 for (;;) {
alpar@9 1814 /* Make sure that we have a literal to write. */
alpar@9 1815 if (s->lookahead == 0) {
alpar@9 1816 fill_window(s);
alpar@9 1817 if (s->lookahead == 0) {
alpar@9 1818 if (flush == Z_NO_FLUSH)
alpar@9 1819 return need_more;
alpar@9 1820 break; /* flush the current block */
alpar@9 1821 }
alpar@9 1822 }
alpar@9 1823
alpar@9 1824 /* Output a literal byte */
alpar@9 1825 s->match_length = 0;
alpar@9 1826 Tracevv((stderr,"%c", s->window[s->strstart]));
alpar@9 1827 _tr_tally_lit (s, s->window[s->strstart], bflush);
alpar@9 1828 s->lookahead--;
alpar@9 1829 s->strstart++;
alpar@9 1830 if (bflush) FLUSH_BLOCK(s, 0);
alpar@9 1831 }
alpar@9 1832 FLUSH_BLOCK(s, flush == Z_FINISH);
alpar@9 1833 return flush == Z_FINISH ? finish_done : block_done;
alpar@9 1834 }