GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libz/deflate.c Lines: 0 559 0.0 %
Date: 2017-11-13 Branches: 0 512 0.0 %

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/*	$OpenBSD: deflate.c,v 1.11 2009/10/27 23:59:31 deraadt Exp $	*/
2
/* deflate.c -- compress data using the deflation algorithm
3
 * Copyright (C) 1995-2005 Jean-loup Gailly.
4
 * For conditions of distribution and use, see copyright notice in zlib.h
5
 */
6
7
/*
8
 *  ALGORITHM
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 *
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 *      The "deflation" process depends on being able to identify portions
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 *      of the input text which are identical to earlier input (within a
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 *      sliding window trailing behind the input currently being processed).
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 *
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 *      The most straightforward technique turns out to be the fastest for
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 *      most input files: try all possible matches and select the longest.
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 *      The key feature of this algorithm is that insertions into the string
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 *      dictionary are very simple and thus fast, and deletions are avoided
18
 *      completely. Insertions are performed at each input character, whereas
19
 *      string matches are performed only when the previous match ends. So it
20
 *      is preferable to spend more time in matches to allow very fast string
21
 *      insertions and avoid deletions. The matching algorithm for small
22
 *      strings is inspired from that of Rabin & Karp. A brute force approach
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 *      is used to find longer strings when a small match has been found.
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 *      A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
25
 *      (by Leonid Broukhis).
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 *         A previous version of this file used a more sophisticated algorithm
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 *      (by Fiala and Greene) which is guaranteed to run in linear amortized
28
 *      time, but has a larger average cost, uses more memory and is patented.
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 *      However the F&G algorithm may be faster for some highly redundant
30
 *      files if the parameter max_chain_length (described below) is too large.
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 *
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 *  ACKNOWLEDGEMENTS
33
 *
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 *      The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
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 *      I found it in 'freeze' written by Leonid Broukhis.
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 *      Thanks to many people for bug reports and testing.
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 *
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 *  REFERENCES
39
 *
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 *      Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
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 *      Available in http://www.ietf.org/rfc/rfc1951.txt
42
 *
43
 *      A description of the Rabin and Karp algorithm is given in the book
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 *         "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
45
 *
46
 *      Fiala,E.R., and Greene,D.H.
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 *         Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
48
 *
49
 */
50
51
52
#include "deflate.h"
53
54
/*
55
  If you use the zlib library in a product, an acknowledgment is welcome
56
  in the documentation of your product. If for some reason you cannot
57
  include such an acknowledgment, I would appreciate that you keep this
58
  copyright string in the executable of your product.
59
 */
60
61
/* ===========================================================================
62
 *  Function prototypes.
63
 */
64
typedef enum {
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    need_more,      /* block not completed, need more input or more output */
66
    block_done,     /* block flush performed */
67
    finish_started, /* finish started, need only more output at next deflate */
68
    finish_done     /* finish done, accept no more input or output */
69
} block_state;
70
71
typedef block_state (*compress_func) OF((deflate_state *s, int flush));
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/* Compression function. Returns the block state after the call. */
73
74
local void fill_window    OF((deflate_state *s));
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local block_state deflate_stored OF((deflate_state *s, int flush));
76
local block_state deflate_fast   OF((deflate_state *s, int flush));
77
#ifndef FASTEST
78
local block_state deflate_slow   OF((deflate_state *s, int flush));
79
#endif
80
local void lm_init        OF((deflate_state *s));
81
local void putShortMSB    OF((deflate_state *s, uInt b));
82
local void flush_pending  OF((z_streamp strm));
83
local int read_buf        OF((z_streamp strm, Bytef *buf, unsigned size));
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#ifndef FASTEST
85
#ifdef ASMV
86
      void match_init OF((void)); /* asm code initialization */
87
      uInt longest_match  OF((deflate_state *s, IPos cur_match));
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#else
89
local uInt longest_match  OF((deflate_state *s, IPos cur_match));
90
#endif
91
#endif
92
local uInt longest_match_fast OF((deflate_state *s, IPos cur_match));
93
94
#ifdef DEBUG
95
local  void check_match OF((deflate_state *s, IPos start, IPos match,
96
                            int length));
97
#endif
98
99
/* ===========================================================================
100
 * Local data
101
 */
102
103
#define NIL 0
104
/* Tail of hash chains */
105
106
#ifndef TOO_FAR
107
#  define TOO_FAR 4096
108
#endif
109
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
110
111
#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
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/* Minimum amount of lookahead, except at the end of the input file.
113
 * See deflate.c for comments about the MIN_MATCH+1.
114
 */
115
116
/* Values for max_lazy_match, good_match and max_chain_length, depending on
117
 * the desired pack level (0..9). The values given below have been tuned to
118
 * exclude worst case performance for pathological files. Better values may be
119
 * found for specific files.
120
 */
121
typedef struct config_s {
122
   ush good_length; /* reduce lazy search above this match length */
123
   ush max_lazy;    /* do not perform lazy search above this match length */
124
   ush nice_length; /* quit search above this match length */
125
   ush max_chain;
126
   compress_func func;
127
} config;
128
129
#ifdef FASTEST
130
local const config configuration_table[2] = {
131
/*      good lazy nice chain */
132
/* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */
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/* 1 */ {4,    4,  8,    4, deflate_fast}}; /* max speed, no lazy matches */
134
#else
135
local const config configuration_table[10] = {
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/*      good lazy nice chain */
137
/* 0 */ {0,    0,  0,    0, deflate_stored},  /* store only */
138
/* 1 */ {4,    4,  8,    4, deflate_fast}, /* max speed, no lazy matches */
139
/* 2 */ {4,    5, 16,    8, deflate_fast},
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/* 3 */ {4,    6, 32,   32, deflate_fast},
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/* 4 */ {4,    4, 16,   16, deflate_slow},  /* lazy matches */
143
/* 5 */ {8,   16, 32,   32, deflate_slow},
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/* 6 */ {8,   16, 128, 128, deflate_slow},
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/* 7 */ {8,   32, 128, 256, deflate_slow},
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/* 8 */ {32, 128, 258, 1024, deflate_slow},
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/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
148
#endif
149
150
/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
151
 * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
152
 * meaning.
153
 */
154
155
#define EQUAL 0
156
/* result of memcmp for equal strings */
157
158
#ifndef NO_DUMMY_DECL
159
struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
160
#endif
161
162
/* ===========================================================================
163
 * Update a hash value with the given input byte
164
 * IN  assertion: all calls to UPDATE_HASH are made with consecutive
165
 *    input characters, so that a running hash key can be computed from the
166
 *    previous key instead of complete recalculation each time.
167
 */
168
#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
169
170
171
/* ===========================================================================
172
 * Insert string str in the dictionary and set match_head to the previous head
173
 * of the hash chain (the most recent string with same hash key). Return
174
 * the previous length of the hash chain.
175
 * If this file is compiled with -DFASTEST, the compression level is forced
176
 * to 1, and no hash chains are maintained.
177
 * IN  assertion: all calls to INSERT_STRING are made with consecutive
178
 *    input characters and the first MIN_MATCH bytes of str are valid
179
 *    (except for the last MIN_MATCH-1 bytes of the input file).
180
 */
181
#ifdef FASTEST
182
#define INSERT_STRING(s, str, match_head) \
183
   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
184
    match_head = s->head[s->ins_h], \
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    s->head[s->ins_h] = (Pos)(str))
186
#else
187
#define INSERT_STRING(s, str, match_head) \
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   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
189
    match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
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    s->head[s->ins_h] = (Pos)(str))
191
#endif
192
193
/* ===========================================================================
194
 * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
195
 * prev[] will be initialized on the fly.
196
 */
197
#define CLEAR_HASH(s) \
198
    s->head[s->hash_size-1] = NIL; \
199
    zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
200
201
/* ========================================================================= */
202
int ZEXPORT deflateInit_(strm, level, version, stream_size)
203
    z_streamp strm;
204
    int level;
205
    const char *version;
206
    int stream_size;
207
{
208
    return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
209
                         Z_DEFAULT_STRATEGY, version, stream_size);
210
    /* To do: ignore strm->next_in if we use it as window */
211
}
212
213
/* ========================================================================= */
214
int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
215
                  version, stream_size)
216
    z_streamp strm;
217
    int  level;
218
    int  method;
219
    int  windowBits;
220
    int  memLevel;
221
    int  strategy;
222
    const char *version;
223
    int stream_size;
224
{
225
    deflate_state *s;
226
    int wrap = 1;
227
    static const char my_version[] = ZLIB_VERSION;
228
229
    ushf *overlay;
230
    /* We overlay pending_buf and d_buf+l_buf. This works since the average
231
     * output size for (length,distance) codes is <= 24 bits.
232
     */
233
234
    if (version == Z_NULL || version[0] != my_version[0] ||
235
        stream_size != sizeof(z_stream)) {
236
        return Z_VERSION_ERROR;
237
    }
238
    if (strm == Z_NULL) return Z_STREAM_ERROR;
239
240
    strm->msg = Z_NULL;
241
    if (strm->zalloc == (alloc_func)0) {
242
        strm->zalloc = zcalloc;
243
        strm->opaque = (voidpf)0;
244
    }
245
    if (strm->zfree == (free_func)0) strm->zfree = zcfree;
246
247
#ifdef FASTEST
248
    if (level != 0) level = 1;
249
#else
250
    if (level == Z_DEFAULT_COMPRESSION) level = 6;
251
#endif
252
253
    if (windowBits < 0) { /* suppress zlib wrapper */
254
        wrap = 0;
255
        windowBits = -windowBits;
256
    }
257
#ifdef GZIP
258
    else if (windowBits > 15) {
259
        wrap = 2;       /* write gzip wrapper instead */
260
        windowBits -= 16;
261
    }
262
#endif
263
    if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
264
        windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
265
        strategy < 0 || strategy > Z_FIXED) {
266
        return Z_STREAM_ERROR;
267
    }
268
    if (windowBits == 8) windowBits = 9;  /* until 256-byte window bug fixed */
269
    s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
270
    if (s == Z_NULL) return Z_MEM_ERROR;
271
    strm->state = (struct internal_state FAR *)s;
272
    s->strm = strm;
273
274
    s->wrap = wrap;
275
    s->gzhead = Z_NULL;
276
    s->w_bits = windowBits;
277
    s->w_size = 1 << s->w_bits;
278
    s->w_mask = s->w_size - 1;
279
280
    s->hash_bits = memLevel + 7;
281
    s->hash_size = 1 << s->hash_bits;
282
    s->hash_mask = s->hash_size - 1;
283
    s->hash_shift =  ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
284
285
    s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
286
    s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
287
    s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
288
289
    s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
290
291
    overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
292
    s->pending_buf = (uchf *) overlay;
293
    s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
294
295
    if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
296
        s->pending_buf == Z_NULL) {
297
        s->status = FINISH_STATE;
298
        strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
299
        deflateEnd (strm);
300
        return Z_MEM_ERROR;
301
    }
302
    s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
303
    s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
304
305
    s->level = level;
306
    s->strategy = strategy;
307
    s->method = (Byte)method;
308
309
    return deflateReset(strm);
310
}
311
312
/* ========================================================================= */
313
int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
314
    z_streamp strm;
315
    const Bytef *dictionary;
316
    uInt  dictLength;
317
{
318
    deflate_state *s;
319
    uInt length = dictLength;
320
    uInt n;
321
    IPos hash_head = 0;
322
323
    if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
324
        strm->state->wrap == 2 ||
325
        (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
326
        return Z_STREAM_ERROR;
327
328
    s = strm->state;
329
    if (s->wrap)
330
        strm->adler = adler32(strm->adler, dictionary, dictLength);
331
332
    if (length < MIN_MATCH) return Z_OK;
333
    if (length > MAX_DIST(s)) {
334
        length = MAX_DIST(s);
335
        dictionary += dictLength - length; /* use the tail of the dictionary */
336
    }
337
    zmemcpy(s->window, dictionary, length);
338
    s->strstart = length;
339
    s->block_start = (long)length;
340
341
    /* Insert all strings in the hash table (except for the last two bytes).
342
     * s->lookahead stays null, so s->ins_h will be recomputed at the next
343
     * call of fill_window.
344
     */
345
    s->ins_h = s->window[0];
346
    UPDATE_HASH(s, s->ins_h, s->window[1]);
347
    for (n = 0; n <= length - MIN_MATCH; n++) {
348
        INSERT_STRING(s, n, hash_head);
349
    }
350
    if (hash_head) hash_head = 0;  /* to make compiler happy */
351
    return Z_OK;
352
}
353
354
/* ========================================================================= */
355
int ZEXPORT deflateReset (strm)
356
    z_streamp strm;
357
{
358
    deflate_state *s;
359
360
    if (strm == Z_NULL || strm->state == Z_NULL ||
361
        strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
362
        return Z_STREAM_ERROR;
363
    }
364
365
    strm->total_in = strm->total_out = 0;
366
    strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
367
    strm->data_type = Z_UNKNOWN;
368
369
    s = (deflate_state *)strm->state;
370
    s->pending = 0;
371
    s->pending_out = s->pending_buf;
372
373
    if (s->wrap < 0) {
374
        s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
375
    }
376
    s->status = s->wrap ? INIT_STATE : BUSY_STATE;
377
    strm->adler =
378
#ifdef GZIP
379
        s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
380
#endif
381
        adler32(0L, Z_NULL, 0);
382
    s->last_flush = Z_NO_FLUSH;
383
384
    _tr_init(s);
385
    lm_init(s);
386
387
    return Z_OK;
388
}
389
390
/* ========================================================================= */
391
int ZEXPORT deflateSetHeader (strm, head)
392
    z_streamp strm;
393
    gz_headerp head;
394
{
395
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
396
    if (strm->state->wrap != 2) return Z_STREAM_ERROR;
397
    strm->state->gzhead = head;
398
    return Z_OK;
399
}
400
401
/* ========================================================================= */
402
int ZEXPORT deflatePrime (strm, bits, value)
403
    z_streamp strm;
404
    int bits;
405
    int value;
406
{
407
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
408
    strm->state->bi_valid = bits;
409
    strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
410
    return Z_OK;
411
}
412
413
/* ========================================================================= */
414
int ZEXPORT deflateParams(strm, level, strategy)
415
    z_streamp strm;
416
    int level;
417
    int strategy;
418
{
419
    deflate_state *s;
420
    compress_func func;
421
    int err = Z_OK;
422
423
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
424
    s = strm->state;
425
426
#ifdef FASTEST
427
    if (level != 0) level = 1;
428
#else
429
    if (level == Z_DEFAULT_COMPRESSION) level = 6;
430
#endif
431
    if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
432
        return Z_STREAM_ERROR;
433
    }
434
    func = configuration_table[s->level].func;
435
436
    if (func != configuration_table[level].func && strm->total_in != 0) {
437
        /* Flush the last buffer: */
438
        err = deflate(strm, Z_PARTIAL_FLUSH);
439
    }
440
    if (s->level != level) {
441
        s->level = level;
442
        s->max_lazy_match   = configuration_table[level].max_lazy;
443
        s->good_match       = configuration_table[level].good_length;
444
        s->nice_match       = configuration_table[level].nice_length;
445
        s->max_chain_length = configuration_table[level].max_chain;
446
    }
447
    s->strategy = strategy;
448
    return err;
449
}
450
451
/* ========================================================================= */
452
int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
453
    z_streamp strm;
454
    int good_length;
455
    int max_lazy;
456
    int nice_length;
457
    int max_chain;
458
{
459
    deflate_state *s;
460
461
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
462
    s = strm->state;
463
    s->good_match = good_length;
464
    s->max_lazy_match = max_lazy;
465
    s->nice_match = nice_length;
466
    s->max_chain_length = max_chain;
467
    return Z_OK;
468
}
469
470
/* =========================================================================
471
 * For the default windowBits of 15 and memLevel of 8, this function returns
472
 * a close to exact, as well as small, upper bound on the compressed size.
473
 * They are coded as constants here for a reason--if the #define's are
474
 * changed, then this function needs to be changed as well.  The return
475
 * value for 15 and 8 only works for those exact settings.
476
 *
477
 * For any setting other than those defaults for windowBits and memLevel,
478
 * the value returned is a conservative worst case for the maximum expansion
479
 * resulting from using fixed blocks instead of stored blocks, which deflate
480
 * can emit on compressed data for some combinations of the parameters.
481
 *
482
 * This function could be more sophisticated to provide closer upper bounds
483
 * for every combination of windowBits and memLevel, as well as wrap.
484
 * But even the conservative upper bound of about 14% expansion does not
485
 * seem onerous for output buffer allocation.
486
 */
487
uLong ZEXPORT deflateBound(strm, sourceLen)
488
    z_streamp strm;
489
    uLong sourceLen;
490
{
491
    deflate_state *s;
492
    uLong destLen;
493
494
    /* conservative upper bound */
495
    destLen = sourceLen +
496
              ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
497
498
    /* if can't get parameters, return conservative bound */
499
    if (strm == Z_NULL || strm->state == Z_NULL)
500
        return destLen;
501
502
    /* if not default parameters, return conservative bound */
503
    s = strm->state;
504
    if (s->w_bits != 15 || s->hash_bits != 8 + 7)
505
        return destLen;
506
507
    /* default settings: return tight bound for that case */
508
    return compressBound(sourceLen);
509
}
510
511
/* =========================================================================
512
 * Put a short in the pending buffer. The 16-bit value is put in MSB order.
513
 * IN assertion: the stream state is correct and there is enough room in
514
 * pending_buf.
515
 */
516
local void putShortMSB (s, b)
517
    deflate_state *s;
518
    uInt b;
519
{
520
    put_byte(s, (Byte)(b >> 8));
521
    put_byte(s, (Byte)(b & 0xff));
522
}
523
524
/* =========================================================================
525
 * Flush as much pending output as possible. All deflate() output goes
526
 * through this function so some applications may wish to modify it
527
 * to avoid allocating a large strm->next_out buffer and copying into it.
528
 * (See also read_buf()).
529
 */
530
local void flush_pending(strm)
531
    z_streamp strm;
532
{
533
    unsigned len = strm->state->pending;
534
535
    if (len > strm->avail_out) len = strm->avail_out;
536
    if (len == 0) return;
537
538
    zmemcpy(strm->next_out, strm->state->pending_out, len);
539
    strm->next_out  += len;
540
    strm->state->pending_out  += len;
541
    strm->total_out += len;
542
    strm->avail_out  -= len;
543
    strm->state->pending -= len;
544
    if (strm->state->pending == 0) {
545
        strm->state->pending_out = strm->state->pending_buf;
546
    }
547
}
548
549
/* ========================================================================= */
550
int ZEXPORT deflate (strm, flush)
551
    z_streamp strm;
552
    int flush;
553
{
554
    int old_flush; /* value of flush param for previous deflate call */
555
    deflate_state *s;
556
557
    if (strm == Z_NULL || strm->state == Z_NULL ||
558
        flush > Z_FINISH || flush < 0) {
559
        return Z_STREAM_ERROR;
560
    }
561
    s = strm->state;
562
563
    if (strm->next_out == Z_NULL ||
564
        (strm->next_in == Z_NULL && strm->avail_in != 0) ||
565
        (s->status == FINISH_STATE && flush != Z_FINISH)) {
566
        ERR_RETURN(strm, Z_STREAM_ERROR);
567
    }
568
    if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
569
570
    s->strm = strm; /* just in case */
571
    old_flush = s->last_flush;
572
    s->last_flush = flush;
573
574
    /* Write the header */
575
    if (s->status == INIT_STATE) {
576
#ifdef GZIP
577
        if (s->wrap == 2) {
578
            strm->adler = crc32(0L, Z_NULL, 0);
579
            put_byte(s, 31);
580
            put_byte(s, 139);
581
            put_byte(s, 8);
582
            if (s->gzhead == NULL) {
583
                put_byte(s, 0);
584
                put_byte(s, 0);
585
                put_byte(s, 0);
586
                put_byte(s, 0);
587
                put_byte(s, 0);
588
                put_byte(s, s->level == 9 ? 2 :
589
                            (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
590
                             4 : 0));
591
                put_byte(s, OS_CODE);
592
                s->status = BUSY_STATE;
593
            }
594
            else {
595
                put_byte(s, (s->gzhead->text ? 1 : 0) +
596
                            (s->gzhead->hcrc ? 2 : 0) +
597
                            (s->gzhead->extra == Z_NULL ? 0 : 4) +
598
                            (s->gzhead->name == Z_NULL ? 0 : 8) +
599
                            (s->gzhead->comment == Z_NULL ? 0 : 16)
600
                        );
601
                put_byte(s, (Byte)(s->gzhead->time & 0xff));
602
                put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
603
                put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
604
                put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
605
                put_byte(s, s->level == 9 ? 2 :
606
                            (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
607
                             4 : 0));
608
                put_byte(s, s->gzhead->os & 0xff);
609
                if (s->gzhead->extra != NULL) {
610
                    put_byte(s, s->gzhead->extra_len & 0xff);
611
                    put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
612
                }
613
                if (s->gzhead->hcrc)
614
                    strm->adler = crc32(strm->adler, s->pending_buf,
615
                                        s->pending);
616
                s->gzindex = 0;
617
                s->status = EXTRA_STATE;
618
            }
619
        }
620
        else
621
#endif
622
        {
623
            uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
624
            uInt level_flags;
625
626
            if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
627
                level_flags = 0;
628
            else if (s->level < 6)
629
                level_flags = 1;
630
            else if (s->level == 6)
631
                level_flags = 2;
632
            else
633
                level_flags = 3;
634
            header |= (level_flags << 6);
635
            if (s->strstart != 0) header |= PRESET_DICT;
636
            header += 31 - (header % 31);
637
638
            s->status = BUSY_STATE;
639
            putShortMSB(s, header);
640
641
            /* Save the adler32 of the preset dictionary: */
642
            if (s->strstart != 0) {
643
                putShortMSB(s, (uInt)(strm->adler >> 16));
644
                putShortMSB(s, (uInt)(strm->adler & 0xffff));
645
            }
646
            strm->adler = adler32(0L, Z_NULL, 0);
647
        }
648
    }
649
#ifdef GZIP
650
    if (s->status == EXTRA_STATE) {
651
        if (s->gzhead->extra != NULL) {
652
            uInt beg = s->pending;  /* start of bytes to update crc */
653
654
            while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
655
                if (s->pending == s->pending_buf_size) {
656
                    if (s->gzhead->hcrc && s->pending > beg)
657
                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
658
                                            s->pending - beg);
659
                    flush_pending(strm);
660
                    beg = s->pending;
661
                    if (s->pending == s->pending_buf_size)
662
                        break;
663
                }
664
                put_byte(s, s->gzhead->extra[s->gzindex]);
665
                s->gzindex++;
666
            }
667
            if (s->gzhead->hcrc && s->pending > beg)
668
                strm->adler = crc32(strm->adler, s->pending_buf + beg,
669
                                    s->pending - beg);
670
            if (s->gzindex == s->gzhead->extra_len) {
671
                s->gzindex = 0;
672
                s->status = NAME_STATE;
673
            }
674
        }
675
        else
676
            s->status = NAME_STATE;
677
    }
678
    if (s->status == NAME_STATE) {
679
        if (s->gzhead->name != NULL) {
680
            uInt beg = s->pending;  /* start of bytes to update crc */
681
            int val;
682
683
            do {
684
                if (s->pending == s->pending_buf_size) {
685
                    if (s->gzhead->hcrc && s->pending > beg)
686
                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
687
                                            s->pending - beg);
688
                    flush_pending(strm);
689
                    beg = s->pending;
690
                    if (s->pending == s->pending_buf_size) {
691
                        val = 1;
692
                        break;
693
                    }
694
                }
695
                val = s->gzhead->name[s->gzindex++];
696
                put_byte(s, val);
697
            } while (val != 0);
698
            if (s->gzhead->hcrc && s->pending > beg)
699
                strm->adler = crc32(strm->adler, s->pending_buf + beg,
700
                                    s->pending - beg);
701
            if (val == 0) {
702
                s->gzindex = 0;
703
                s->status = COMMENT_STATE;
704
            }
705
        }
706
        else
707
            s->status = COMMENT_STATE;
708
    }
709
    if (s->status == COMMENT_STATE) {
710
        if (s->gzhead->comment != NULL) {
711
            uInt beg = s->pending;  /* start of bytes to update crc */
712
            int val;
713
714
            do {
715
                if (s->pending == s->pending_buf_size) {
716
                    if (s->gzhead->hcrc && s->pending > beg)
717
                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
718
                                            s->pending - beg);
719
                    flush_pending(strm);
720
                    beg = s->pending;
721
                    if (s->pending == s->pending_buf_size) {
722
                        val = 1;
723
                        break;
724
                    }
725
                }
726
                val = s->gzhead->comment[s->gzindex++];
727
                put_byte(s, val);
728
            } while (val != 0);
729
            if (s->gzhead->hcrc && s->pending > beg)
730
                strm->adler = crc32(strm->adler, s->pending_buf + beg,
731
                                    s->pending - beg);
732
            if (val == 0)
733
                s->status = HCRC_STATE;
734
        }
735
        else
736
            s->status = HCRC_STATE;
737
    }
738
    if (s->status == HCRC_STATE) {
739
        if (s->gzhead->hcrc) {
740
            if (s->pending + 2 > s->pending_buf_size)
741
                flush_pending(strm);
742
            if (s->pending + 2 <= s->pending_buf_size) {
743
                put_byte(s, (Byte)(strm->adler & 0xff));
744
                put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
745
                strm->adler = crc32(0L, Z_NULL, 0);
746
                s->status = BUSY_STATE;
747
            }
748
        }
749
        else
750
            s->status = BUSY_STATE;
751
    }
752
#endif
753
754
    /* Flush as much pending output as possible */
755
    if (s->pending != 0) {
756
        flush_pending(strm);
757
        if (strm->avail_out == 0) {
758
            /* Since avail_out is 0, deflate will be called again with
759
             * more output space, but possibly with both pending and
760
             * avail_in equal to zero. There won't be anything to do,
761
             * but this is not an error situation so make sure we
762
             * return OK instead of BUF_ERROR at next call of deflate:
763
             */
764
            s->last_flush = -1;
765
            return Z_OK;
766
        }
767
768
    /* Make sure there is something to do and avoid duplicate consecutive
769
     * flushes. For repeated and useless calls with Z_FINISH, we keep
770
     * returning Z_STREAM_END instead of Z_BUF_ERROR.
771
     */
772
    } else if (strm->avail_in == 0 && flush <= old_flush &&
773
               flush != Z_FINISH) {
774
        ERR_RETURN(strm, Z_BUF_ERROR);
775
    }
776
777
    /* User must not provide more input after the first FINISH: */
778
    if (s->status == FINISH_STATE && strm->avail_in != 0) {
779
        ERR_RETURN(strm, Z_BUF_ERROR);
780
    }
781
782
    /* Start a new block or continue the current one.
783
     */
784
    if (strm->avail_in != 0 || s->lookahead != 0 ||
785
        (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
786
        block_state bstate;
787
788
        bstate = (*(configuration_table[s->level].func))(s, flush);
789
790
        if (bstate == finish_started || bstate == finish_done) {
791
            s->status = FINISH_STATE;
792
        }
793
        if (bstate == need_more || bstate == finish_started) {
794
            if (strm->avail_out == 0) {
795
                s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
796
            }
797
            return Z_OK;
798
            /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
799
             * of deflate should use the same flush parameter to make sure
800
             * that the flush is complete. So we don't have to output an
801
             * empty block here, this will be done at next call. This also
802
             * ensures that for a very small output buffer, we emit at most
803
             * one empty block.
804
             */
805
        }
806
        if (bstate == block_done) {
807
            if (flush == Z_PARTIAL_FLUSH) {
808
                _tr_align(s);
809
            } else { /* FULL_FLUSH or SYNC_FLUSH */
810
                _tr_stored_block(s, (char*)0, 0L, 0);
811
                /* For a full flush, this empty block will be recognized
812
                 * as a special marker by inflate_sync().
813
                 */
814
                if (flush == Z_FULL_FLUSH) {
815
                    CLEAR_HASH(s);             /* forget history */
816
                }
817
            }
818
            flush_pending(strm);
819
            if (strm->avail_out == 0) {
820
              s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
821
              return Z_OK;
822
            }
823
        }
824
    }
825
    Assert(strm->avail_out > 0, "bug2");
826
827
    if (flush != Z_FINISH) return Z_OK;
828
    if (s->wrap <= 0) return Z_STREAM_END;
829
830
    /* Write the trailer */
831
#ifdef GZIP
832
    if (s->wrap == 2) {
833
        put_byte(s, (Byte)(strm->adler & 0xff));
834
        put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
835
        put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
836
        put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
837
        put_byte(s, (Byte)(strm->total_in & 0xff));
838
        put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
839
        put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
840
        put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
841
    }
842
    else
843
#endif
844
    {
845
        putShortMSB(s, (uInt)(strm->adler >> 16));
846
        putShortMSB(s, (uInt)(strm->adler & 0xffff));
847
    }
848
    flush_pending(strm);
849
    /* If avail_out is zero, the application will call deflate again
850
     * to flush the rest.
851
     */
852
    if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
853
    return s->pending != 0 ? Z_OK : Z_STREAM_END;
854
}
855
856
/* ========================================================================= */
857
int ZEXPORT deflateEnd (strm)
858
    z_streamp strm;
859
{
860
    int status;
861
862
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
863
864
    status = strm->state->status;
865
    if (status != INIT_STATE &&
866
        status != EXTRA_STATE &&
867
        status != NAME_STATE &&
868
        status != COMMENT_STATE &&
869
        status != HCRC_STATE &&
870
        status != BUSY_STATE &&
871
        status != FINISH_STATE) {
872
      return Z_STREAM_ERROR;
873
    }
874
875
    /* Deallocate in reverse order of allocations: */
876
    TRY_FREE(strm, strm->state->pending_buf);
877
    TRY_FREE(strm, strm->state->head);
878
    TRY_FREE(strm, strm->state->prev);
879
    TRY_FREE(strm, strm->state->window);
880
881
    ZFREE(strm, strm->state);
882
    strm->state = Z_NULL;
883
884
    return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
885
}
886
887
/* =========================================================================
888
 * Copy the source state to the destination state.
889
 * To simplify the source, this is not supported for 16-bit MSDOS (which
890
 * doesn't have enough memory anyway to duplicate compression states).
891
 */
892
int ZEXPORT deflateCopy (dest, source)
893
    z_streamp dest;
894
    z_streamp source;
895
{
896
#ifdef MAXSEG_64K
897
    return Z_STREAM_ERROR;
898
#else
899
    deflate_state *ds;
900
    deflate_state *ss;
901
    ushf *overlay;
902
903
904
    if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
905
        return Z_STREAM_ERROR;
906
    }
907
908
    ss = source->state;
909
910
    zmemcpy(dest, source, sizeof(z_stream));
911
912
    ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
913
    if (ds == Z_NULL) return Z_MEM_ERROR;
914
    dest->state = (struct internal_state FAR *) ds;
915
    zmemcpy(ds, ss, sizeof(deflate_state));
916
    ds->strm = dest;
917
918
    ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
919
    ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));
920
    ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));
921
    overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
922
    ds->pending_buf = (uchf *) overlay;
923
924
    if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
925
        ds->pending_buf == Z_NULL) {
926
        deflateEnd (dest);
927
        return Z_MEM_ERROR;
928
    }
929
    /* following zmemcpy do not work for 16-bit MSDOS */
930
    zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
931
    zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
932
    zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
933
    zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
934
935
    ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
936
    ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
937
    ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
938
939
    ds->l_desc.dyn_tree = ds->dyn_ltree;
940
    ds->d_desc.dyn_tree = ds->dyn_dtree;
941
    ds->bl_desc.dyn_tree = ds->bl_tree;
942
943
    return Z_OK;
944
#endif /* MAXSEG_64K */
945
}
946
947
/* ===========================================================================
948
 * Read a new buffer from the current input stream, update the adler32
949
 * and total number of bytes read.  All deflate() input goes through
950
 * this function so some applications may wish to modify it to avoid
951
 * allocating a large strm->next_in buffer and copying from it.
952
 * (See also flush_pending()).
953
 */
954
local int read_buf(strm, buf, size)
955
    z_streamp strm;
956
    Bytef *buf;
957
    unsigned size;
958
{
959
    unsigned len = strm->avail_in;
960
961
    if (len > size) len = size;
962
    if (len == 0) return 0;
963
964
    strm->avail_in  -= len;
965
966
    if (strm->state->wrap == 1) {
967
        strm->adler = adler32(strm->adler, strm->next_in, len);
968
    }
969
#ifdef GZIP
970
    else if (strm->state->wrap == 2) {
971
        strm->adler = crc32(strm->adler, strm->next_in, len);
972
    }
973
#endif
974
    zmemcpy(buf, strm->next_in, len);
975
    strm->next_in  += len;
976
    strm->total_in += len;
977
978
    return (int)len;
979
}
980
981
/* ===========================================================================
982
 * Initialize the "longest match" routines for a new zlib stream
983
 */
984
local void lm_init (s)
985
    deflate_state *s;
986
{
987
    s->window_size = (ulg)2L*s->w_size;
988
989
    CLEAR_HASH(s);
990
991
    /* Set the default configuration parameters:
992
     */
993
    s->max_lazy_match   = configuration_table[s->level].max_lazy;
994
    s->good_match       = configuration_table[s->level].good_length;
995
    s->nice_match       = configuration_table[s->level].nice_length;
996
    s->max_chain_length = configuration_table[s->level].max_chain;
997
998
    s->strstart = 0;
999
    s->block_start = 0L;
1000
    s->lookahead = 0;
1001
    s->match_length = s->prev_length = MIN_MATCH-1;
1002
    s->match_available = 0;
1003
    s->ins_h = 0;
1004
#ifndef FASTEST
1005
#ifdef ASMV
1006
    match_init(); /* initialize the asm code */
1007
#endif
1008
#endif
1009
}
1010
1011
#ifndef FASTEST
1012
/* ===========================================================================
1013
 * Set match_start to the longest match starting at the given string and
1014
 * return its length. Matches shorter or equal to prev_length are discarded,
1015
 * in which case the result is equal to prev_length and match_start is
1016
 * garbage.
1017
 * IN assertions: cur_match is the head of the hash chain for the current
1018
 *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
1019
 * OUT assertion: the match length is not greater than s->lookahead.
1020
 */
1021
#ifndef ASMV
1022
/* For 80x86 and 680x0, an optimized version will be provided in match.asm or
1023
 * match.S. The code will be functionally equivalent.
1024
 */
1025
local uInt longest_match(s, cur_match)
1026
    deflate_state *s;
1027
    IPos cur_match;                             /* current match */
1028
{
1029
    unsigned chain_length = s->max_chain_length;/* max hash chain length */
1030
    register Bytef *scan = s->window + s->strstart; /* current string */
1031
    register Bytef *match;                       /* matched string */
1032
    register int len;                           /* length of current match */
1033
    int best_len = s->prev_length;              /* best match length so far */
1034
    int nice_match = s->nice_match;             /* stop if match long enough */
1035
    IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
1036
        s->strstart - (IPos)MAX_DIST(s) : NIL;
1037
    /* Stop when cur_match becomes <= limit. To simplify the code,
1038
     * we prevent matches with the string of window index 0.
1039
     */
1040
    Posf *prev = s->prev;
1041
    uInt wmask = s->w_mask;
1042
1043
#ifdef UNALIGNED_OK
1044
    /* Compare two bytes at a time. Note: this is not always beneficial.
1045
     * Try with and without -DUNALIGNED_OK to check.
1046
     */
1047
    register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
1048
    register ush scan_start = *(ushf*)scan;
1049
    register ush scan_end   = *(ushf*)(scan+best_len-1);
1050
#else
1051
    register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1052
    register Byte scan_end1  = scan[best_len-1];
1053
    register Byte scan_end   = scan[best_len];
1054
#endif
1055
1056
    /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1057
     * It is easy to get rid of this optimization if necessary.
1058
     */
1059
    Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1060
1061
    /* Do not waste too much time if we already have a good match: */
1062
    if (s->prev_length >= s->good_match) {
1063
        chain_length >>= 2;
1064
    }
1065
    /* Do not look for matches beyond the end of the input. This is necessary
1066
     * to make deflate deterministic.
1067
     */
1068
    if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
1069
1070
    Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1071
1072
    do {
1073
        Assert(cur_match < s->strstart, "no future");
1074
        match = s->window + cur_match;
1075
1076
        /* Skip to next match if the match length cannot increase
1077
         * or if the match length is less than 2.  Note that the checks below
1078
         * for insufficient lookahead only occur occasionally for performance
1079
         * reasons.  Therefore uninitialized memory will be accessed, and
1080
         * conditional jumps will be made that depend on those values.
1081
         * However the length of the match is limited to the lookahead, so
1082
         * the output of deflate is not affected by the uninitialized values.
1083
         */
1084
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1085
        /* This code assumes sizeof(unsigned short) == 2. Do not use
1086
         * UNALIGNED_OK if your compiler uses a different size.
1087
         */
1088
        if (*(ushf*)(match+best_len-1) != scan_end ||
1089
            *(ushf*)match != scan_start) continue;
1090
1091
        /* It is not necessary to compare scan[2] and match[2] since they are
1092
         * always equal when the other bytes match, given that the hash keys
1093
         * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1094
         * strstart+3, +5, ... up to strstart+257. We check for insufficient
1095
         * lookahead only every 4th comparison; the 128th check will be made
1096
         * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
1097
         * necessary to put more guard bytes at the end of the window, or
1098
         * to check more often for insufficient lookahead.
1099
         */
1100
        Assert(scan[2] == match[2], "scan[2]?");
1101
        scan++, match++;
1102
        do {
1103
        } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1104
                 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1105
                 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1106
                 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1107
                 scan < strend);
1108
        /* The funny "do {}" generates better code on most compilers */
1109
1110
        /* Here, scan <= window+strstart+257 */
1111
        Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1112
        if (*scan == *match) scan++;
1113
1114
        len = (MAX_MATCH - 1) - (int)(strend-scan);
1115
        scan = strend - (MAX_MATCH-1);
1116
1117
#else /* UNALIGNED_OK */
1118
1119
        if (match[best_len]   != scan_end  ||
1120
            match[best_len-1] != scan_end1 ||
1121
            *match            != *scan     ||
1122
            *++match          != scan[1])      continue;
1123
1124
        /* The check at best_len-1 can be removed because it will be made
1125
         * again later. (This heuristic is not always a win.)
1126
         * It is not necessary to compare scan[2] and match[2] since they
1127
         * are always equal when the other bytes match, given that
1128
         * the hash keys are equal and that HASH_BITS >= 8.
1129
         */
1130
        scan += 2, match++;
1131
        Assert(*scan == *match, "match[2]?");
1132
1133
        /* We check for insufficient lookahead only every 8th comparison;
1134
         * the 256th check will be made at strstart+258.
1135
         */
1136
        do {
1137
        } while (*++scan == *++match && *++scan == *++match &&
1138
                 *++scan == *++match && *++scan == *++match &&
1139
                 *++scan == *++match && *++scan == *++match &&
1140
                 *++scan == *++match && *++scan == *++match &&
1141
                 scan < strend);
1142
1143
        Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1144
1145
        len = MAX_MATCH - (int)(strend - scan);
1146
        scan = strend - MAX_MATCH;
1147
1148
#endif /* UNALIGNED_OK */
1149
1150
        if (len > best_len) {
1151
            s->match_start = cur_match;
1152
            best_len = len;
1153
            if (len >= nice_match) break;
1154
#ifdef UNALIGNED_OK
1155
            scan_end = *(ushf*)(scan+best_len-1);
1156
#else
1157
            scan_end1  = scan[best_len-1];
1158
            scan_end   = scan[best_len];
1159
#endif
1160
        }
1161
    } while ((cur_match = prev[cur_match & wmask]) > limit
1162
             && --chain_length != 0);
1163
1164
    if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
1165
    return s->lookahead;
1166
}
1167
#endif /* ASMV */
1168
#endif /* FASTEST */
1169
1170
/* ---------------------------------------------------------------------------
1171
 * Optimized version for level == 1 or strategy == Z_RLE only
1172
 */
1173
local uInt longest_match_fast(s, cur_match)
1174
    deflate_state *s;
1175
    IPos cur_match;                             /* current match */
1176
{
1177
    register Bytef *scan = s->window + s->strstart; /* current string */
1178
    register Bytef *match;                       /* matched string */
1179
    register int len;                           /* length of current match */
1180
    register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1181
1182
    /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1183
     * It is easy to get rid of this optimization if necessary.
1184
     */
1185
    Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1186
1187
    Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1188
1189
    Assert(cur_match < s->strstart, "no future");
1190
1191
    match = s->window + cur_match;
1192
1193
    /* Return failure if the match length is less than 2:
1194
     */
1195
    if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
1196
1197
    /* The check at best_len-1 can be removed because it will be made
1198
     * again later. (This heuristic is not always a win.)
1199
     * It is not necessary to compare scan[2] and match[2] since they
1200
     * are always equal when the other bytes match, given that
1201
     * the hash keys are equal and that HASH_BITS >= 8.
1202
     */
1203
    scan += 2, match += 2;
1204
    Assert(*scan == *match, "match[2]?");
1205
1206
    /* We check for insufficient lookahead only every 8th comparison;
1207
     * the 256th check will be made at strstart+258.
1208
     */
1209
    do {
1210
    } while (*++scan == *++match && *++scan == *++match &&
1211
             *++scan == *++match && *++scan == *++match &&
1212
             *++scan == *++match && *++scan == *++match &&
1213
             *++scan == *++match && *++scan == *++match &&
1214
             scan < strend);
1215
1216
    Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1217
1218
    len = MAX_MATCH - (int)(strend - scan);
1219
1220
    if (len < MIN_MATCH) return MIN_MATCH - 1;
1221
1222
    s->match_start = cur_match;
1223
    return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
1224
}
1225
1226
#ifdef DEBUG
1227
/* ===========================================================================
1228
 * Check that the match at match_start is indeed a match.
1229
 */
1230
local void check_match(s, start, match, length)
1231
    deflate_state *s;
1232
    IPos start, match;
1233
    int length;
1234
{
1235
    /* check that the match is indeed a match */
1236
    if (zmemcmp(s->window + match,
1237
                s->window + start, length) != EQUAL) {
1238
        fprintf(stderr, " start %u, match %u, length %d\n",
1239
                start, match, length);
1240
        do {
1241
            fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
1242
        } while (--length != 0);
1243
        z_error("invalid match");
1244
    }
1245
    if (z_verbose > 1) {
1246
        fprintf(stderr,"\\[%d,%d]", start-match, length);
1247
        do { putc(s->window[start++], stderr); } while (--length != 0);
1248
    }
1249
}
1250
#else
1251
#  define check_match(s, start, match, length)
1252
#endif /* DEBUG */
1253
1254
/* ===========================================================================
1255
 * Fill the window when the lookahead becomes insufficient.
1256
 * Updates strstart and lookahead.
1257
 *
1258
 * IN assertion: lookahead < MIN_LOOKAHEAD
1259
 * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
1260
 *    At least one byte has been read, or avail_in == 0; reads are
1261
 *    performed for at least two bytes (required for the zip translate_eol
1262
 *    option -- not supported here).
1263
 */
1264
local void fill_window(s)
1265
    deflate_state *s;
1266
{
1267
    register unsigned n, m;
1268
    register Posf *p;
1269
    unsigned more;    /* Amount of free space at the end of the window. */
1270
    uInt wsize = s->w_size;
1271
1272
    do {
1273
        more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
1274
1275
        /* Deal with !@#$% 64K limit: */
1276
        if (sizeof(int) <= 2) {
1277
            if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
1278
                more = wsize;
1279
1280
            } else if (more == (unsigned)(-1)) {
1281
                /* Very unlikely, but possible on 16 bit machine if
1282
                 * strstart == 0 && lookahead == 1 (input done a byte at time)
1283
                 */
1284
                more--;
1285
            }
1286
        }
1287
1288
        /* If the window is almost full and there is insufficient lookahead,
1289
         * move the upper half to the lower one to make room in the upper half.
1290
         */
1291
        if (s->strstart >= wsize+MAX_DIST(s)) {
1292
1293
            zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
1294
            s->match_start -= wsize;
1295
            s->strstart    -= wsize; /* we now have strstart >= MAX_DIST */
1296
            s->block_start -= (long) wsize;
1297
1298
            /* Slide the hash table (could be avoided with 32 bit values
1299
               at the expense of memory usage). We slide even when level == 0
1300
               to keep the hash table consistent if we switch back to level > 0
1301
               later. (Using level 0 permanently is not an optimal usage of
1302
               zlib, so we don't care about this pathological case.)
1303
             */
1304
            /* %%% avoid this when Z_RLE */
1305
            n = s->hash_size;
1306
            p = &s->head[n];
1307
            do {
1308
                m = *--p;
1309
                *p = (Pos)(m >= wsize ? m-wsize : NIL);
1310
            } while (--n);
1311
1312
            n = wsize;
1313
#ifndef FASTEST
1314
            p = &s->prev[n];
1315
            do {
1316
                m = *--p;
1317
                *p = (Pos)(m >= wsize ? m-wsize : NIL);
1318
                /* If n is not on any hash chain, prev[n] is garbage but
1319
                 * its value will never be used.
1320
                 */
1321
            } while (--n);
1322
#endif
1323
            more += wsize;
1324
        }
1325
        if (s->strm->avail_in == 0) return;
1326
1327
        /* If there was no sliding:
1328
         *    strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
1329
         *    more == window_size - lookahead - strstart
1330
         * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
1331
         * => more >= window_size - 2*WSIZE + 2
1332
         * In the BIG_MEM or MMAP case (not yet supported),
1333
         *   window_size == input_size + MIN_LOOKAHEAD  &&
1334
         *   strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
1335
         * Otherwise, window_size == 2*WSIZE so more >= 2.
1336
         * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
1337
         */
1338
        Assert(more >= 2, "more < 2");
1339
1340
        n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
1341
        s->lookahead += n;
1342
1343
        /* Initialize the hash value now that we have some input: */
1344
        if (s->lookahead >= MIN_MATCH) {
1345
            s->ins_h = s->window[s->strstart];
1346
            UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1347
#if MIN_MATCH != 3
1348
            Call UPDATE_HASH() MIN_MATCH-3 more times
1349
#endif
1350
        }
1351
        /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
1352
         * but this is not important since only literal bytes will be emitted.
1353
         */
1354
1355
    } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
1356
}
1357
1358
/* ===========================================================================
1359
 * Flush the current block, with given end-of-file flag.
1360
 * IN assertion: strstart is set to the end of the current match.
1361
 */
1362
#define FLUSH_BLOCK_ONLY(s, eof) { \
1363
   _tr_flush_block(s, (s->block_start >= 0L ? \
1364
                   (charf *)&s->window[(unsigned)s->block_start] : \
1365
                   (charf *)Z_NULL), \
1366
                (ulg)((long)s->strstart - s->block_start), \
1367
                (eof)); \
1368
   s->block_start = s->strstart; \
1369
   flush_pending(s->strm); \
1370
   Tracev((stderr,"[FLUSH]")); \
1371
}
1372
1373
/* Same but force premature exit if necessary. */
1374
#define FLUSH_BLOCK(s, eof) { \
1375
   FLUSH_BLOCK_ONLY(s, eof); \
1376
   if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
1377
}
1378
1379
/* ===========================================================================
1380
 * Copy without compression as much as possible from the input stream, return
1381
 * the current block state.
1382
 * This function does not insert new strings in the dictionary since
1383
 * uncompressible data is probably not useful. This function is used
1384
 * only for the level=0 compression option.
1385
 * NOTE: this function should be optimized to avoid extra copying from
1386
 * window to pending_buf.
1387
 */
1388
local block_state deflate_stored(s, flush)
1389
    deflate_state *s;
1390
    int flush;
1391
{
1392
    /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
1393
     * to pending_buf_size, and each stored block has a 5 byte header:
1394
     */
1395
    ulg max_block_size = 0xffff;
1396
    ulg max_start;
1397
1398
    if (max_block_size > s->pending_buf_size - 5) {
1399
        max_block_size = s->pending_buf_size - 5;
1400
    }
1401
1402
    /* Copy as much as possible from input to output: */
1403
    for (;;) {
1404
        /* Fill the window as much as possible: */
1405
        if (s->lookahead <= 1) {
1406
1407
            Assert(s->strstart < s->w_size+MAX_DIST(s) ||
1408
                   s->block_start >= (long)s->w_size, "slide too late");
1409
1410
            fill_window(s);
1411
            if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
1412
1413
            if (s->lookahead == 0) break; /* flush the current block */
1414
        }
1415
        Assert(s->block_start >= 0L, "block gone");
1416
1417
        s->strstart += s->lookahead;
1418
        s->lookahead = 0;
1419
1420
        /* Emit a stored block if pending_buf will be full: */
1421
        max_start = s->block_start + max_block_size;
1422
        if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
1423
            /* strstart == 0 is possible when wraparound on 16-bit machine */
1424
            s->lookahead = (uInt)(s->strstart - max_start);
1425
            s->strstart = (uInt)max_start;
1426
            FLUSH_BLOCK(s, 0);
1427
        }
1428
        /* Flush if we may have to slide, otherwise block_start may become
1429
         * negative and the data will be gone:
1430
         */
1431
        if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
1432
            FLUSH_BLOCK(s, 0);
1433
        }
1434
    }
1435
    FLUSH_BLOCK(s, flush == Z_FINISH);
1436
    return flush == Z_FINISH ? finish_done : block_done;
1437
}
1438
1439
/* ===========================================================================
1440
 * Compress as much as possible from the input stream, return the current
1441
 * block state.
1442
 * This function does not perform lazy evaluation of matches and inserts
1443
 * new strings in the dictionary only for unmatched strings or for short
1444
 * matches. It is used only for the fast compression options.
1445
 */
1446
local block_state deflate_fast(s, flush)
1447
    deflate_state *s;
1448
    int flush;
1449
{
1450
    IPos hash_head = NIL; /* head of the hash chain */
1451
    int bflush;           /* set if current block must be flushed */
1452
1453
    for (;;) {
1454
        /* Make sure that we always have enough lookahead, except
1455
         * at the end of the input file. We need MAX_MATCH bytes
1456
         * for the next match, plus MIN_MATCH bytes to insert the
1457
         * string following the next match.
1458
         */
1459
        if (s->lookahead < MIN_LOOKAHEAD) {
1460
            fill_window(s);
1461
            if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1462
                return need_more;
1463
            }
1464
            if (s->lookahead == 0) break; /* flush the current block */
1465
        }
1466
1467
        /* Insert the string window[strstart .. strstart+2] in the
1468
         * dictionary, and set hash_head to the head of the hash chain:
1469
         */
1470
        if (s->lookahead >= MIN_MATCH) {
1471
            INSERT_STRING(s, s->strstart, hash_head);
1472
        }
1473
1474
        /* Find the longest match, discarding those <= prev_length.
1475
         * At this point we have always match_length < MIN_MATCH
1476
         */
1477
        if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
1478
            /* To simplify the code, we prevent matches with the string
1479
             * of window index 0 (in particular we have to avoid a match
1480
             * of the string with itself at the start of the input file).
1481
             */
1482
#ifdef FASTEST
1483
            if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) ||
1484
                (s->strategy == Z_RLE && s->strstart - hash_head == 1)) {
1485
                s->match_length = longest_match_fast (s, hash_head);
1486
            }
1487
#else
1488
            if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
1489
                s->match_length = longest_match (s, hash_head);
1490
            } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
1491
                s->match_length = longest_match_fast (s, hash_head);
1492
            }
1493
#endif
1494
            /* longest_match() or longest_match_fast() sets match_start */
1495
        }
1496
        if (s->match_length >= MIN_MATCH) {
1497
            check_match(s, s->strstart, s->match_start, s->match_length);
1498
1499
            _tr_tally_dist(s, s->strstart - s->match_start,
1500
                           s->match_length - MIN_MATCH, bflush);
1501
1502
            s->lookahead -= s->match_length;
1503
1504
            /* Insert new strings in the hash table only if the match length
1505
             * is not too large. This saves time but degrades compression.
1506
             */
1507
#ifndef FASTEST
1508
            if (s->match_length <= s->max_insert_length &&
1509
                s->lookahead >= MIN_MATCH) {
1510
                s->match_length--; /* string at strstart already in table */
1511
                do {
1512
                    s->strstart++;
1513
                    INSERT_STRING(s, s->strstart, hash_head);
1514
                    /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1515
                     * always MIN_MATCH bytes ahead.
1516
                     */
1517
                } while (--s->match_length != 0);
1518
                s->strstart++;
1519
            } else
1520
#endif
1521
            {
1522
                s->strstart += s->match_length;
1523
                s->match_length = 0;
1524
                s->ins_h = s->window[s->strstart];
1525
                UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1526
#if MIN_MATCH != 3
1527
                Call UPDATE_HASH() MIN_MATCH-3 more times
1528
#endif
1529
                /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
1530
                 * matter since it will be recomputed at next deflate call.
1531
                 */
1532
            }
1533
        } else {
1534
            /* No match, output a literal byte */
1535
            Tracevv((stderr,"%c", s->window[s->strstart]));
1536
            _tr_tally_lit (s, s->window[s->strstart], bflush);
1537
            s->lookahead--;
1538
            s->strstart++;
1539
        }
1540
        if (bflush) FLUSH_BLOCK(s, 0);
1541
    }
1542
    FLUSH_BLOCK(s, flush == Z_FINISH);
1543
    return flush == Z_FINISH ? finish_done : block_done;
1544
}
1545
1546
#ifndef FASTEST
1547
/* ===========================================================================
1548
 * Same as above, but achieves better compression. We use a lazy
1549
 * evaluation for matches: a match is finally adopted only if there is
1550
 * no better match at the next window position.
1551
 */
1552
local block_state deflate_slow(s, flush)
1553
    deflate_state *s;
1554
    int flush;
1555
{
1556
    IPos hash_head = NIL;    /* head of hash chain */
1557
    int bflush;              /* set if current block must be flushed */
1558
1559
    /* Process the input block. */
1560
    for (;;) {
1561
        /* Make sure that we always have enough lookahead, except
1562
         * at the end of the input file. We need MAX_MATCH bytes
1563
         * for the next match, plus MIN_MATCH bytes to insert the
1564
         * string following the next match.
1565
         */
1566
        if (s->lookahead < MIN_LOOKAHEAD) {
1567
            fill_window(s);
1568
            if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1569
                return need_more;
1570
            }
1571
            if (s->lookahead == 0) break; /* flush the current block */
1572
        }
1573
1574
        /* Insert the string window[strstart .. strstart+2] in the
1575
         * dictionary, and set hash_head to the head of the hash chain:
1576
         */
1577
        if (s->lookahead >= MIN_MATCH) {
1578
            INSERT_STRING(s, s->strstart, hash_head);
1579
        }
1580
1581
        /* Find the longest match, discarding those <= prev_length.
1582
         */
1583
        s->prev_length = s->match_length, s->prev_match = s->match_start;
1584
        s->match_length = MIN_MATCH-1;
1585
1586
        if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
1587
            s->strstart - hash_head <= MAX_DIST(s)) {
1588
            /* To simplify the code, we prevent matches with the string
1589
             * of window index 0 (in particular we have to avoid a match
1590
             * of the string with itself at the start of the input file).
1591
             */
1592
            if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
1593
                s->match_length = longest_match (s, hash_head);
1594
            } else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
1595
                s->match_length = longest_match_fast (s, hash_head);
1596
            }
1597
            /* longest_match() or longest_match_fast() sets match_start */
1598
1599
            if (s->match_length <= 5 && (s->strategy == Z_FILTERED
1600
#if TOO_FAR <= 32767
1601
                || (s->match_length == MIN_MATCH &&
1602
                    s->strstart - s->match_start > TOO_FAR)
1603
#endif
1604
                )) {
1605
1606
                /* If prev_match is also MIN_MATCH, match_start is garbage
1607
                 * but we will ignore the current match anyway.
1608
                 */
1609
                s->match_length = MIN_MATCH-1;
1610
            }
1611
        }
1612
        /* If there was a match at the previous step and the current
1613
         * match is not better, output the previous match:
1614
         */
1615
        if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
1616
            uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
1617
            /* Do not insert strings in hash table beyond this. */
1618
1619
            check_match(s, s->strstart-1, s->prev_match, s->prev_length);
1620
1621
            _tr_tally_dist(s, s->strstart -1 - s->prev_match,
1622
                           s->prev_length - MIN_MATCH, bflush);
1623
1624
            /* Insert in hash table all strings up to the end of the match.
1625
             * strstart-1 and strstart are already inserted. If there is not
1626
             * enough lookahead, the last two strings are not inserted in
1627
             * the hash table.
1628
             */
1629
            s->lookahead -= s->prev_length-1;
1630
            s->prev_length -= 2;
1631
            do {
1632
                if (++s->strstart <= max_insert) {
1633
                    INSERT_STRING(s, s->strstart, hash_head);
1634
                }
1635
            } while (--s->prev_length != 0);
1636
            s->match_available = 0;
1637
            s->match_length = MIN_MATCH-1;
1638
            s->strstart++;
1639
1640
            if (bflush) FLUSH_BLOCK(s, 0);
1641
1642
        } else if (s->match_available) {
1643
            /* If there was no match at the previous position, output a
1644
             * single literal. If there was a match but the current match
1645
             * is longer, truncate the previous match to a single literal.
1646
             */
1647
            Tracevv((stderr,"%c", s->window[s->strstart-1]));
1648
            _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1649
            if (bflush) {
1650
                FLUSH_BLOCK_ONLY(s, 0);
1651
            }
1652
            s->strstart++;
1653
            s->lookahead--;
1654
            if (s->strm->avail_out == 0) return need_more;
1655
        } else {
1656
            /* There is no previous match to compare with, wait for
1657
             * the next step to decide.
1658
             */
1659
            s->match_available = 1;
1660
            s->strstart++;
1661
            s->lookahead--;
1662
        }
1663
    }
1664
    Assert (flush != Z_NO_FLUSH, "no flush?");
1665
    if (s->match_available) {
1666
        Tracevv((stderr,"%c", s->window[s->strstart-1]));
1667
        _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1668
        s->match_available = 0;
1669
    }
1670
    FLUSH_BLOCK(s, flush == Z_FINISH);
1671
    return flush == Z_FINISH ? finish_done : block_done;
1672
}
1673
#endif /* FASTEST */
1674
1675
#if 0
1676
/* ===========================================================================
1677
 * For Z_RLE, simply look for runs of bytes, generate matches only of distance
1678
 * one.  Do not maintain a hash table.  (It will be regenerated if this run of
1679
 * deflate switches away from Z_RLE.)
1680
 */
1681
local block_state deflate_rle(s, flush)
1682
    deflate_state *s;
1683
    int flush;
1684
{
1685
    int bflush;         /* set if current block must be flushed */
1686
    uInt run;           /* length of run */
1687
    uInt max;           /* maximum length of run */
1688
    uInt prev;          /* byte at distance one to match */
1689
    Bytef *scan;        /* scan for end of run */
1690
1691
    for (;;) {
1692
        /* Make sure that we always have enough lookahead, except
1693
         * at the end of the input file. We need MAX_MATCH bytes
1694
         * for the longest encodable run.
1695
         */
1696
        if (s->lookahead < MAX_MATCH) {
1697
            fill_window(s);
1698
            if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
1699
                return need_more;
1700
            }
1701
            if (s->lookahead == 0) break; /* flush the current block */
1702
        }
1703
1704
        /* See how many times the previous byte repeats */
1705
        run = 0;
1706
        if (s->strstart > 0) {      /* if there is a previous byte, that is */
1707
            max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH;
1708
            scan = s->window + s->strstart - 1;
1709
            prev = *scan++;
1710
            do {
1711
                if (*scan++ != prev)
1712
                    break;
1713
            } while (++run < max);
1714
        }
1715
1716
        /* Emit match if have run of MIN_MATCH or longer, else emit literal */
1717
        if (run >= MIN_MATCH) {
1718
            check_match(s, s->strstart, s->strstart - 1, run);
1719
            _tr_tally_dist(s, 1, run - MIN_MATCH, bflush);
1720
            s->lookahead -= run;
1721
            s->strstart += run;
1722
        } else {
1723
            /* No match, output a literal byte */
1724
            Tracevv((stderr,"%c", s->window[s->strstart]));
1725
            _tr_tally_lit (s, s->window[s->strstart], bflush);
1726
            s->lookahead--;
1727
            s->strstart++;
1728
        }
1729
        if (bflush) FLUSH_BLOCK(s, 0);
1730
    }
1731
    FLUSH_BLOCK(s, flush == Z_FINISH);
1732
    return flush == Z_FINISH ? finish_done : block_done;
1733
}
1734
#endif