root/lib/zlib/deflate.c

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DEFINITIONS

This source file includes following definitions.
  1. deflateInit_
  2. deflateInit2_
  3. deflateSetDictionary
  4. deflateReset
  5. deflateSetHeader
  6. deflatePrime
  7. deflateParams
  8. deflateTune
  9. deflateBound
  10. putShortMSB
  11. flush_pending
  12. deflate
  13. deflateEnd
  14. deflateCopy
  15. read_buf
  16. lm_init
  17. longest_match
  18. longest_match_fast
  19. check_match
  20. fill_window
  21. deflate_stored
  22. deflate_fast
  23. deflate_slow
  24. deflate_rle

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

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