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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [zlib/] [deflate.c] - Blame information for rev 818

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1 745 jeremybenn
/* 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: deflate.c,v 1.1.1.2 2002/03/11 21:53:23 tromey Exp $ */
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
#define EQUAL 0
158
/* result of memcmp for equal strings */
159
 
160
#ifndef NO_DUMMY_DECL
161
struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
162
#endif
163
 
164
/* ===========================================================================
165
 * Update a hash value with the given input byte
166
 * IN  assertion: all calls to to UPDATE_HASH are made with consecutive
167
 *    input characters, so that a running hash key can be computed from the
168
 *    previous key instead of complete recalculation each time.
169
 */
170
#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
171
 
172
 
173
/* ===========================================================================
174
 * Insert string str in the dictionary and set match_head to the previous head
175
 * of the hash chain (the most recent string with same hash key). Return
176
 * the previous length of the hash chain.
177
 * If this file is compiled with -DFASTEST, the compression level is forced
178
 * to 1, and no hash chains are maintained.
179
 * IN  assertion: all calls to to INSERT_STRING are made with consecutive
180
 *    input characters and the first MIN_MATCH bytes of str are valid
181
 *    (except for the last MIN_MATCH-1 bytes of the input file).
182
 */
183
#ifdef FASTEST
184
#define INSERT_STRING(s, str, match_head) \
185
   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
186
    match_head = s->head[s->ins_h], \
187
    s->head[s->ins_h] = (Pos)(str))
188
#else
189
#define INSERT_STRING(s, str, match_head) \
190
   (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
191
    match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
192
    s->head[s->ins_h] = (Pos)(str))
193
#endif
194
 
195
/* ===========================================================================
196
 * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
197
 * prev[] will be initialized on the fly.
198
 */
199
#define CLEAR_HASH(s) \
200
    s->head[s->hash_size-1] = NIL; \
201
    zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
202
 
203
/* ========================================================================= */
204
int ZEXPORT deflateInit_(strm, level, version, stream_size)
205
    z_streamp strm;
206
    int level;
207
    const char *version;
208
    int stream_size;
209
{
210
    return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
211
                         Z_DEFAULT_STRATEGY, version, stream_size);
212
    /* To do: ignore strm->next_in if we use it as window */
213
}
214
 
215
/* ========================================================================= */
216
int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
217
                  version, stream_size)
218
    z_streamp strm;
219
    int  level;
220
    int  method;
221
    int  windowBits;
222
    int  memLevel;
223
    int  strategy;
224
    const char *version;
225
    int stream_size;
226
{
227
    deflate_state *s;
228
    int wrap = 1;
229
    static const char my_version[] = ZLIB_VERSION;
230
 
231
    ushf *overlay;
232
    /* We overlay pending_buf and d_buf+l_buf. This works since the average
233
     * output size for (length,distance) codes is <= 24 bits.
234
     */
235
 
236
    if (version == Z_NULL || version[0] != my_version[0] ||
237
        stream_size != sizeof(z_stream)) {
238
        return Z_VERSION_ERROR;
239
    }
240
    if (strm == Z_NULL) return Z_STREAM_ERROR;
241
 
242
    strm->msg = Z_NULL;
243
    if (strm->zalloc == (alloc_func)0) {
244
        strm->zalloc = zcalloc;
245
        strm->opaque = (voidpf)0;
246
    }
247
    if (strm->zfree == (free_func)0) strm->zfree = zcfree;
248
 
249
#ifdef FASTEST
250
    if (level != 0) level = 1;
251
#else
252
    if (level == Z_DEFAULT_COMPRESSION) level = 6;
253
#endif
254
 
255
    if (windowBits < 0) { /* suppress zlib wrapper */
256
        wrap = 0;
257
        windowBits = -windowBits;
258
    }
259
#ifdef GZIP
260
    else if (windowBits > 15) {
261
        wrap = 2;       /* write gzip wrapper instead */
262
        windowBits -= 16;
263
    }
264
#endif
265
    if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
266
        windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
267
        strategy < 0 || strategy > Z_FIXED) {
268
        return Z_STREAM_ERROR;
269
    }
270
    if (windowBits == 8) windowBits = 9;  /* until 256-byte window bug fixed */
271
    s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
272
    if (s == Z_NULL) return Z_MEM_ERROR;
273
    strm->state = (struct internal_state FAR *)s;
274
    s->strm = strm;
275
 
276
    s->wrap = wrap;
277
    s->gzhead = Z_NULL;
278
    s->w_bits = windowBits;
279
    s->w_size = 1 << s->w_bits;
280
    s->w_mask = s->w_size - 1;
281
 
282
    s->hash_bits = memLevel + 7;
283
    s->hash_size = 1 << s->hash_bits;
284
    s->hash_mask = s->hash_size - 1;
285
    s->hash_shift =  ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
286
 
287
    s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
288
    s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
289
    s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
290
 
291
    s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
292
 
293
    overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
294
    s->pending_buf = (uchf *) overlay;
295
    s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
296
 
297
    if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
298
        s->pending_buf == Z_NULL) {
299
        s->status = FINISH_STATE;
300
        strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
301
        deflateEnd (strm);
302
        return Z_MEM_ERROR;
303
    }
304
    s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
305
    s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
306
 
307
    s->level = level;
308
    s->strategy = strategy;
309
    s->method = (Byte)method;
310
 
311
    return deflateReset(strm);
312
}
313
 
314
/* ========================================================================= */
315
int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
316
    z_streamp strm;
317
    const Bytef *dictionary;
318
    uInt  dictLength;
319
{
320
    deflate_state *s;
321
    uInt length = dictLength;
322
    uInt n;
323
    IPos hash_head = 0;
324
 
325
    if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
326
        strm->state->wrap == 2 ||
327
        (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
328
        return Z_STREAM_ERROR;
329
 
330
    s = strm->state;
331
    if (s->wrap)
332
        strm->adler = adler32(strm->adler, dictionary, dictLength);
333
 
334
    if (length < MIN_MATCH) return Z_OK;
335
    if (length > MAX_DIST(s)) {
336
        length = MAX_DIST(s);
337
        dictionary += dictLength - length; /* use the tail of the dictionary */
338
    }
339
    zmemcpy(s->window, dictionary, length);
340
    s->strstart = length;
341
    s->block_start = (long)length;
342
 
343
    /* Insert all strings in the hash table (except for the last two bytes).
344
     * s->lookahead stays null, so s->ins_h will be recomputed at the next
345
     * call of fill_window.
346
     */
347
    s->ins_h = s->window[0];
348
    UPDATE_HASH(s, s->ins_h, s->window[1]);
349
    for (n = 0; n <= length - MIN_MATCH; n++) {
350
        INSERT_STRING(s, n, hash_head);
351
    }
352
    if (hash_head) hash_head = 0;  /* to make compiler happy */
353
    return Z_OK;
354
}
355
 
356
/* ========================================================================= */
357
int ZEXPORT deflateReset (strm)
358
    z_streamp strm;
359
{
360
    deflate_state *s;
361
 
362
    if (strm == Z_NULL || strm->state == Z_NULL ||
363
        strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
364
        return Z_STREAM_ERROR;
365
    }
366
 
367
    strm->total_in = strm->total_out = 0;
368
    strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
369
    strm->data_type = Z_UNKNOWN;
370
 
371
    s = (deflate_state *)strm->state;
372
    s->pending = 0;
373
    s->pending_out = s->pending_buf;
374
 
375
    if (s->wrap < 0) {
376
        s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
377
    }
378
    s->status = s->wrap ? INIT_STATE : BUSY_STATE;
379
    strm->adler =
380
#ifdef GZIP
381
        s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
382
#endif
383
        adler32(0L, Z_NULL, 0);
384
    s->last_flush = Z_NO_FLUSH;
385
 
386
    _tr_init(s);
387
    lm_init(s);
388
 
389
    return Z_OK;
390
}
391
 
392
/* ========================================================================= */
393
int ZEXPORT deflateSetHeader (strm, head)
394
    z_streamp strm;
395
    gz_headerp head;
396
{
397
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
398
    if (strm->state->wrap != 2) return Z_STREAM_ERROR;
399
    strm->state->gzhead = head;
400
    return Z_OK;
401
}
402
 
403
/* ========================================================================= */
404
int ZEXPORT deflatePrime (strm, bits, value)
405
    z_streamp strm;
406
    int bits;
407
    int value;
408
{
409
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
410
    strm->state->bi_valid = bits;
411
    strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
412
    return Z_OK;
413
}
414
 
415
/* ========================================================================= */
416
int ZEXPORT deflateParams(strm, level, strategy)
417
    z_streamp strm;
418
    int level;
419
    int strategy;
420
{
421
    deflate_state *s;
422
    compress_func func;
423
    int err = Z_OK;
424
 
425
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
426
    s = strm->state;
427
 
428
#ifdef FASTEST
429
    if (level != 0) level = 1;
430
#else
431
    if (level == Z_DEFAULT_COMPRESSION) level = 6;
432
#endif
433
    if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
434
        return Z_STREAM_ERROR;
435
    }
436
    func = configuration_table[s->level].func;
437
 
438
    if (func != configuration_table[level].func && strm->total_in != 0) {
439
        /* Flush the last buffer: */
440
        err = deflate(strm, Z_PARTIAL_FLUSH);
441
    }
442
    if (s->level != level) {
443
        s->level = level;
444
        s->max_lazy_match   = configuration_table[level].max_lazy;
445
        s->good_match       = configuration_table[level].good_length;
446
        s->nice_match       = configuration_table[level].nice_length;
447
        s->max_chain_length = configuration_table[level].max_chain;
448
    }
449
    s->strategy = strategy;
450
    return err;
451
}
452
 
453
/* ========================================================================= */
454
int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
455
    z_streamp strm;
456
    int good_length;
457
    int max_lazy;
458
    int nice_length;
459
    int max_chain;
460
{
461
    deflate_state *s;
462
 
463
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
464
    s = strm->state;
465
    s->good_match = good_length;
466
    s->max_lazy_match = max_lazy;
467
    s->nice_match = nice_length;
468
    s->max_chain_length = max_chain;
469
    return Z_OK;
470
}
471
 
472
/* =========================================================================
473
 * For the default windowBits of 15 and memLevel of 8, this function returns
474
 * a close to exact, as well as small, upper bound on the compressed size.
475
 * They are coded as constants here for a reason--if the #define's are
476
 * changed, then this function needs to be changed as well.  The return
477
 * value for 15 and 8 only works for those exact settings.
478
 *
479
 * For any setting other than those defaults for windowBits and memLevel,
480
 * the value returned is a conservative worst case for the maximum expansion
481
 * resulting from using fixed blocks instead of stored blocks, which deflate
482
 * can emit on compressed data for some combinations of the parameters.
483
 *
484
 * This function could be more sophisticated to provide closer upper bounds
485
 * for every combination of windowBits and memLevel, as well as wrap.
486
 * But even the conservative upper bound of about 14% expansion does not
487
 * seem onerous for output buffer allocation.
488
 */
489
uLong ZEXPORT deflateBound(strm, sourceLen)
490
    z_streamp strm;
491
    uLong sourceLen;
492
{
493
    deflate_state *s;
494
    uLong destLen;
495
 
496
    /* conservative upper bound */
497
    destLen = sourceLen +
498
              ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
499
 
500
    /* if can't get parameters, return conservative bound */
501
    if (strm == Z_NULL || strm->state == Z_NULL)
502
        return destLen;
503
 
504
    /* if not default parameters, return conservative bound */
505
    s = strm->state;
506
    if (s->w_bits != 15 || s->hash_bits != 8 + 7)
507
        return destLen;
508
 
509
    /* default settings: return tight bound for that case */
510
    return compressBound(sourceLen);
511
}
512
 
513
/* =========================================================================
514
 * Put a short in the pending buffer. The 16-bit value is put in MSB order.
515
 * IN assertion: the stream state is correct and there is enough room in
516
 * pending_buf.
517
 */
518
local void putShortMSB (s, b)
519
    deflate_state *s;
520
    uInt b;
521
{
522
    put_byte(s, (Byte)(b >> 8));
523
    put_byte(s, (Byte)(b & 0xff));
524
}
525
 
526
/* =========================================================================
527
 * Flush as much pending output as possible. All deflate() output goes
528
 * through this function so some applications may wish to modify it
529
 * to avoid allocating a large strm->next_out buffer and copying into it.
530
 * (See also read_buf()).
531
 */
532
local void flush_pending(strm)
533
    z_streamp strm;
534
{
535
    unsigned len = strm->state->pending;
536
 
537
    if (len > strm->avail_out) len = strm->avail_out;
538
    if (len == 0) return;
539
 
540
    zmemcpy(strm->next_out, strm->state->pending_out, len);
541
    strm->next_out  += len;
542
    strm->state->pending_out  += len;
543
    strm->total_out += len;
544
    strm->avail_out  -= len;
545
    strm->state->pending -= len;
546
    if (strm->state->pending == 0) {
547
        strm->state->pending_out = strm->state->pending_buf;
548
    }
549
}
550
 
551
/* ========================================================================= */
552
int ZEXPORT deflate (strm, flush)
553
    z_streamp strm;
554
    int flush;
555
{
556
    int old_flush; /* value of flush param for previous deflate call */
557
    deflate_state *s;
558
 
559
    if (strm == Z_NULL || strm->state == Z_NULL ||
560
        flush > Z_FINISH || flush < 0) {
561
        return Z_STREAM_ERROR;
562
    }
563
    s = strm->state;
564
 
565
    if (strm->next_out == Z_NULL ||
566
        (strm->next_in == Z_NULL && strm->avail_in != 0) ||
567
        (s->status == FINISH_STATE && flush != Z_FINISH)) {
568
        ERR_RETURN(strm, Z_STREAM_ERROR);
569
    }
570
    if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
571
 
572
    s->strm = strm; /* just in case */
573
    old_flush = s->last_flush;
574
    s->last_flush = flush;
575
 
576
    /* Write the header */
577
    if (s->status == INIT_STATE) {
578
#ifdef GZIP
579
        if (s->wrap == 2) {
580
            strm->adler = crc32(0L, Z_NULL, 0);
581
            put_byte(s, 31);
582
            put_byte(s, 139);
583
            put_byte(s, 8);
584
            if (s->gzhead == NULL) {
585
                put_byte(s, 0);
586
                put_byte(s, 0);
587
                put_byte(s, 0);
588
                put_byte(s, 0);
589
                put_byte(s, 0);
590
                put_byte(s, s->level == 9 ? 2 :
591
                            (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
592
                             4 : 0));
593
                put_byte(s, OS_CODE);
594
                s->status = BUSY_STATE;
595
            }
596
            else {
597
                put_byte(s, (s->gzhead->text ? 1 : 0) +
598
                            (s->gzhead->hcrc ? 2 : 0) +
599
                            (s->gzhead->extra == Z_NULL ? 0 : 4) +
600
                            (s->gzhead->name == Z_NULL ? 0 : 8) +
601
                            (s->gzhead->comment == Z_NULL ? 0 : 16)
602
                        );
603
                put_byte(s, (Byte)(s->gzhead->time & 0xff));
604
                put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
605
                put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
606
                put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
607
                put_byte(s, s->level == 9 ? 2 :
608
                            (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
609
                             4 : 0));
610
                put_byte(s, s->gzhead->os & 0xff);
611
                if (s->gzhead->extra != NULL) {
612
                    put_byte(s, s->gzhead->extra_len & 0xff);
613
                    put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
614
                }
615
                if (s->gzhead->hcrc)
616
                    strm->adler = crc32(strm->adler, s->pending_buf,
617
                                        s->pending);
618
                s->gzindex = 0;
619
                s->status = EXTRA_STATE;
620
            }
621
        }
622
        else
623
#endif
624
        {
625
            uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
626
            uInt level_flags;
627
 
628
            if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
629
                level_flags = 0;
630
            else if (s->level < 6)
631
                level_flags = 1;
632
            else if (s->level == 6)
633
                level_flags = 2;
634
            else
635
                level_flags = 3;
636
            header |= (level_flags << 6);
637
            if (s->strstart != 0) header |= PRESET_DICT;
638
            header += 31 - (header % 31);
639
 
640
            s->status = BUSY_STATE;
641
            putShortMSB(s, header);
642
 
643
            /* Save the adler32 of the preset dictionary: */
644
            if (s->strstart != 0) {
645
                putShortMSB(s, (uInt)(strm->adler >> 16));
646
                putShortMSB(s, (uInt)(strm->adler & 0xffff));
647
            }
648
            strm->adler = adler32(0L, Z_NULL, 0);
649
        }
650
    }
651
#ifdef GZIP
652
    if (s->status == EXTRA_STATE) {
653
        if (s->gzhead->extra != NULL) {
654
            uInt beg = s->pending;  /* start of bytes to update crc */
655
 
656
            while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
657
                if (s->pending == s->pending_buf_size) {
658
                    if (s->gzhead->hcrc && s->pending > beg)
659
                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
660
                                            s->pending - beg);
661
                    flush_pending(strm);
662
                    beg = s->pending;
663
                    if (s->pending == s->pending_buf_size)
664
                        break;
665
                }
666
                put_byte(s, s->gzhead->extra[s->gzindex]);
667
                s->gzindex++;
668
            }
669
            if (s->gzhead->hcrc && s->pending > beg)
670
                strm->adler = crc32(strm->adler, s->pending_buf + beg,
671
                                    s->pending - beg);
672
            if (s->gzindex == s->gzhead->extra_len) {
673
                s->gzindex = 0;
674
                s->status = NAME_STATE;
675
            }
676
        }
677
        else
678
            s->status = NAME_STATE;
679
    }
680
    if (s->status == NAME_STATE) {
681
        if (s->gzhead->name != NULL) {
682
            uInt beg = s->pending;  /* start of bytes to update crc */
683
            int val;
684
 
685
            do {
686
                if (s->pending == s->pending_buf_size) {
687
                    if (s->gzhead->hcrc && s->pending > beg)
688
                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
689
                                            s->pending - beg);
690
                    flush_pending(strm);
691
                    beg = s->pending;
692
                    if (s->pending == s->pending_buf_size) {
693
                        val = 1;
694
                        break;
695
                    }
696
                }
697
                val = s->gzhead->name[s->gzindex++];
698
                put_byte(s, val);
699
            } while (val != 0);
700
            if (s->gzhead->hcrc && s->pending > beg)
701
                strm->adler = crc32(strm->adler, s->pending_buf + beg,
702
                                    s->pending - beg);
703
            if (val == 0) {
704
                s->gzindex = 0;
705
                s->status = COMMENT_STATE;
706
            }
707
        }
708
        else
709
            s->status = COMMENT_STATE;
710
    }
711
    if (s->status == COMMENT_STATE) {
712
        if (s->gzhead->comment != NULL) {
713
            uInt beg = s->pending;  /* start of bytes to update crc */
714
            int val;
715
 
716
            do {
717
                if (s->pending == s->pending_buf_size) {
718
                    if (s->gzhead->hcrc && s->pending > beg)
719
                        strm->adler = crc32(strm->adler, s->pending_buf + beg,
720
                                            s->pending - beg);
721
                    flush_pending(strm);
722
                    beg = s->pending;
723
                    if (s->pending == s->pending_buf_size) {
724
                        val = 1;
725
                        break;
726
                    }
727
                }
728
                val = s->gzhead->comment[s->gzindex++];
729
                put_byte(s, val);
730
            } while (val != 0);
731
            if (s->gzhead->hcrc && s->pending > beg)
732
                strm->adler = crc32(strm->adler, s->pending_buf + beg,
733
                                    s->pending - beg);
734
            if (val == 0)
735
                s->status = HCRC_STATE;
736
        }
737
        else
738
            s->status = HCRC_STATE;
739
    }
740
    if (s->status == HCRC_STATE) {
741
        if (s->gzhead->hcrc) {
742
            if (s->pending + 2 > s->pending_buf_size)
743
                flush_pending(strm);
744
            if (s->pending + 2 <= s->pending_buf_size) {
745
                put_byte(s, (Byte)(strm->adler & 0xff));
746
                put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
747
                strm->adler = crc32(0L, Z_NULL, 0);
748
                s->status = BUSY_STATE;
749
            }
750
        }
751
        else
752
            s->status = BUSY_STATE;
753
    }
754
#endif
755
 
756
    /* Flush as much pending output as possible */
757
    if (s->pending != 0) {
758
        flush_pending(strm);
759
        if (strm->avail_out == 0) {
760
            /* Since avail_out is 0, deflate will be called again with
761
             * more output space, but possibly with both pending and
762
             * avail_in equal to zero. There won't be anything to do,
763
             * but this is not an error situation so make sure we
764
             * return OK instead of BUF_ERROR at next call of deflate:
765
             */
766
            s->last_flush = -1;
767
            return Z_OK;
768
        }
769
 
770
    /* Make sure there is something to do and avoid duplicate consecutive
771
     * flushes. For repeated and useless calls with Z_FINISH, we keep
772
     * returning Z_STREAM_END instead of Z_BUF_ERROR.
773
     */
774
    } else if (strm->avail_in == 0 && flush <= old_flush &&
775
               flush != Z_FINISH) {
776
        ERR_RETURN(strm, Z_BUF_ERROR);
777
    }
778
 
779
    /* User must not provide more input after the first FINISH: */
780
    if (s->status == FINISH_STATE && strm->avail_in != 0) {
781
        ERR_RETURN(strm, Z_BUF_ERROR);
782
    }
783
 
784
    /* Start a new block or continue the current one.
785
     */
786
    if (strm->avail_in != 0 || s->lookahead != 0 ||
787
        (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
788
        block_state bstate;
789
 
790
        bstate = (*(configuration_table[s->level].func))(s, flush);
791
 
792
        if (bstate == finish_started || bstate == finish_done) {
793
            s->status = FINISH_STATE;
794
        }
795
        if (bstate == need_more || bstate == finish_started) {
796
            if (strm->avail_out == 0) {
797
                s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
798
            }
799
            return Z_OK;
800
            /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
801
             * of deflate should use the same flush parameter to make sure
802
             * that the flush is complete. So we don't have to output an
803
             * empty block here, this will be done at next call. This also
804
             * ensures that for a very small output buffer, we emit at most
805
             * one empty block.
806
             */
807
        }
808
        if (bstate == block_done) {
809
            if (flush == Z_PARTIAL_FLUSH) {
810
                _tr_align(s);
811
            } else { /* FULL_FLUSH or SYNC_FLUSH */
812
                _tr_stored_block(s, (char*)0, 0L, 0);
813
                /* For a full flush, this empty block will be recognized
814
                 * as a special marker by inflate_sync().
815
                 */
816
                if (flush == Z_FULL_FLUSH) {
817
                    CLEAR_HASH(s);             /* forget history */
818
                }
819
            }
820
            flush_pending(strm);
821
            if (strm->avail_out == 0) {
822
              s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
823
              return Z_OK;
824
            }
825
        }
826
    }
827
    Assert(strm->avail_out > 0, "bug2");
828
 
829
    if (flush != Z_FINISH) return Z_OK;
830
    if (s->wrap <= 0) return Z_STREAM_END;
831
 
832
    /* Write the trailer */
833
#ifdef GZIP
834
    if (s->wrap == 2) {
835
        put_byte(s, (Byte)(strm->adler & 0xff));
836
        put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
837
        put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
838
        put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
839
        put_byte(s, (Byte)(strm->total_in & 0xff));
840
        put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
841
        put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
842
        put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
843
    }
844
    else
845
#endif
846
    {
847
        putShortMSB(s, (uInt)(strm->adler >> 16));
848
        putShortMSB(s, (uInt)(strm->adler & 0xffff));
849
    }
850
    flush_pending(strm);
851
    /* If avail_out is zero, the application will call deflate again
852
     * to flush the rest.
853
     */
854
    if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
855
    return s->pending != 0 ? Z_OK : Z_STREAM_END;
856
}
857
 
858
/* ========================================================================= */
859
int ZEXPORT deflateEnd (strm)
860
    z_streamp strm;
861
{
862
    int status;
863
 
864
    if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
865
 
866
    status = strm->state->status;
867
    if (status != INIT_STATE &&
868
        status != EXTRA_STATE &&
869
        status != NAME_STATE &&
870
        status != COMMENT_STATE &&
871
        status != HCRC_STATE &&
872
        status != BUSY_STATE &&
873
        status != FINISH_STATE) {
874
      return Z_STREAM_ERROR;
875
    }
876
 
877
    /* Deallocate in reverse order of allocations: */
878
    TRY_FREE(strm, strm->state->pending_buf);
879
    TRY_FREE(strm, strm->state->head);
880
    TRY_FREE(strm, strm->state->prev);
881
    TRY_FREE(strm, strm->state->window);
882
 
883
    ZFREE(strm, strm->state);
884
    strm->state = Z_NULL;
885
 
886
    return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
887
}
888
 
889
/* =========================================================================
890
 * Copy the source state to the destination state.
891
 * To simplify the source, this is not supported for 16-bit MSDOS (which
892
 * doesn't have enough memory anyway to duplicate compression states).
893
 */
894
int ZEXPORT deflateCopy (dest, source)
895
    z_streamp dest;
896
    z_streamp source;
897
{
898
#ifdef MAXSEG_64K
899
    return Z_STREAM_ERROR;
900
#else
901
    deflate_state *ds;
902
    deflate_state *ss;
903
    ushf *overlay;
904
 
905
 
906
    if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
907
        return Z_STREAM_ERROR;
908
    }
909
 
910
    ss = source->state;
911
 
912
    zmemcpy(dest, source, sizeof(z_stream));
913
 
914
    ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
915
    if (ds == Z_NULL) return Z_MEM_ERROR;
916
    dest->state = (struct internal_state FAR *) ds;
917
    zmemcpy(ds, ss, sizeof(deflate_state));
918
    ds->strm = dest;
919
 
920
    ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
921
    ds->prev   = (Posf *)  ZALLOC(dest, ds->w_size, sizeof(Pos));
922
    ds->head   = (Posf *)  ZALLOC(dest, ds->hash_size, sizeof(Pos));
923
    overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
924
    ds->pending_buf = (uchf *) overlay;
925
 
926
    if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
927
        ds->pending_buf == Z_NULL) {
928
        deflateEnd (dest);
929
        return Z_MEM_ERROR;
930
    }
931
    /* following zmemcpy do not work for 16-bit MSDOS */
932
    zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
933
    zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
934
    zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
935
    zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
936
 
937
    ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
938
    ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
939
    ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
940
 
941
    ds->l_desc.dyn_tree = ds->dyn_ltree;
942
    ds->d_desc.dyn_tree = ds->dyn_dtree;
943
    ds->bl_desc.dyn_tree = ds->bl_tree;
944
 
945
    return Z_OK;
946
#endif /* MAXSEG_64K */
947
}
948
 
949
/* ===========================================================================
950
 * Read a new buffer from the current input stream, update the adler32
951
 * and total number of bytes read.  All deflate() input goes through
952
 * this function so some applications may wish to modify it to avoid
953
 * allocating a large strm->next_in buffer and copying from it.
954
 * (See also flush_pending()).
955
 */
956
local int read_buf(strm, buf, size)
957
    z_streamp strm;
958
    Bytef *buf;
959
    unsigned size;
960
{
961
    unsigned len = strm->avail_in;
962
 
963
    if (len > size) len = size;
964
    if (len == 0) return 0;
965
 
966
    strm->avail_in  -= len;
967
 
968
    if (strm->state->wrap == 1) {
969
        strm->adler = adler32(strm->adler, strm->next_in, len);
970
    }
971
#ifdef GZIP
972
    else if (strm->state->wrap == 2) {
973
        strm->adler = crc32(strm->adler, strm->next_in, len);
974
    }
975
#endif
976
    zmemcpy(buf, strm->next_in, len);
977
    strm->next_in  += len;
978
    strm->total_in += len;
979
 
980
    return (int)len;
981
}
982
 
983
/* ===========================================================================
984
 * Initialize the "longest match" routines for a new zlib stream
985
 */
986
local void lm_init (s)
987
    deflate_state *s;
988
{
989
    s->window_size = (ulg)2L*s->w_size;
990
 
991
    CLEAR_HASH(s);
992
 
993
    /* Set the default configuration parameters:
994
     */
995
    s->max_lazy_match   = configuration_table[s->level].max_lazy;
996
    s->good_match       = configuration_table[s->level].good_length;
997
    s->nice_match       = configuration_table[s->level].nice_length;
998
    s->max_chain_length = configuration_table[s->level].max_chain;
999
 
1000
    s->strstart = 0;
1001
    s->block_start = 0L;
1002
    s->lookahead = 0;
1003
    s->match_length = s->prev_length = MIN_MATCH-1;
1004
    s->match_available = 0;
1005
    s->ins_h = 0;
1006
#ifndef FASTEST
1007
#ifdef ASMV
1008
    match_init(); /* initialize the asm code */
1009
#endif
1010
#endif
1011
}
1012
 
1013
#ifndef FASTEST
1014
/* ===========================================================================
1015
 * Set match_start to the longest match starting at the given string and
1016
 * return its length. Matches shorter or equal to prev_length are discarded,
1017
 * in which case the result is equal to prev_length and match_start is
1018
 * garbage.
1019
 * IN assertions: cur_match is the head of the hash chain for the current
1020
 *   string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
1021
 * OUT assertion: the match length is not greater than s->lookahead.
1022
 */
1023
#ifndef ASMV
1024
/* For 80x86 and 680x0, an optimized version will be provided in match.asm or
1025
 * match.S. The code will be functionally equivalent.
1026
 */
1027
local uInt longest_match(s, cur_match)
1028
    deflate_state *s;
1029
    IPos cur_match;                             /* current match */
1030
{
1031
    unsigned chain_length = s->max_chain_length;/* max hash chain length */
1032
    register Bytef *scan = s->window + s->strstart; /* current string */
1033
    register Bytef *match;                       /* matched string */
1034
    register int len;                           /* length of current match */
1035
    int best_len = s->prev_length;              /* best match length so far */
1036
    int nice_match = s->nice_match;             /* stop if match long enough */
1037
    IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
1038
        s->strstart - (IPos)MAX_DIST(s) : NIL;
1039
    /* Stop when cur_match becomes <= limit. To simplify the code,
1040
     * we prevent matches with the string of window index 0.
1041
     */
1042
    Posf *prev = s->prev;
1043
    uInt wmask = s->w_mask;
1044
 
1045
#ifdef UNALIGNED_OK
1046
    /* Compare two bytes at a time. Note: this is not always beneficial.
1047
     * Try with and without -DUNALIGNED_OK to check.
1048
     */
1049
    register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
1050
    register ush scan_start = *(ushf*)scan;
1051
    register ush scan_end   = *(ushf*)(scan+best_len-1);
1052
#else
1053
    register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1054
    register Byte scan_end1  = scan[best_len-1];
1055
    register Byte scan_end   = scan[best_len];
1056
#endif
1057
 
1058
    /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1059
     * It is easy to get rid of this optimization if necessary.
1060
     */
1061
    Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1062
 
1063
    /* Do not waste too much time if we already have a good match: */
1064
    if (s->prev_length >= s->good_match) {
1065
        chain_length >>= 2;
1066
    }
1067
    /* Do not look for matches beyond the end of the input. This is necessary
1068
     * to make deflate deterministic.
1069
     */
1070
    if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
1071
 
1072
    Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1073
 
1074
    do {
1075
        Assert(cur_match < s->strstart, "no future");
1076
        match = s->window + cur_match;
1077
 
1078
        /* Skip to next match if the match length cannot increase
1079
         * or if the match length is less than 2.  Note that the checks below
1080
         * for insufficient lookahead only occur occasionally for performance
1081
         * reasons.  Therefore uninitialized memory will be accessed, and
1082
         * conditional jumps will be made that depend on those values.
1083
         * However the length of the match is limited to the lookahead, so
1084
         * the output of deflate is not affected by the uninitialized values.
1085
         */
1086
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1087
        /* This code assumes sizeof(unsigned short) == 2. Do not use
1088
         * UNALIGNED_OK if your compiler uses a different size.
1089
         */
1090
        if (*(ushf*)(match+best_len-1) != scan_end ||
1091
            *(ushf*)match != scan_start) continue;
1092
 
1093
        /* It is not necessary to compare scan[2] and match[2] since they are
1094
         * always equal when the other bytes match, given that the hash keys
1095
         * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1096
         * strstart+3, +5, ... up to strstart+257. We check for insufficient
1097
         * lookahead only every 4th comparison; the 128th check will be made
1098
         * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
1099
         * necessary to put more guard bytes at the end of the window, or
1100
         * to check more often for insufficient lookahead.
1101
         */
1102
        Assert(scan[2] == match[2], "scan[2]?");
1103
        scan++, match++;
1104
        do {
1105
        } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1106
                 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1107
                 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1108
                 *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1109
                 scan < strend);
1110
        /* The funny "do {}" generates better code on most compilers */
1111
 
1112
        /* Here, scan <= window+strstart+257 */
1113
        Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1114
        if (*scan == *match) scan++;
1115
 
1116
        len = (MAX_MATCH - 1) - (int)(strend-scan);
1117
        scan = strend - (MAX_MATCH-1);
1118
 
1119
#else /* UNALIGNED_OK */
1120
 
1121
        if (match[best_len]   != scan_end  ||
1122
            match[best_len-1] != scan_end1 ||
1123
            *match            != *scan     ||
1124
            *++match          != scan[1])      continue;
1125
 
1126
        /* The check at best_len-1 can be removed because it will be made
1127
         * again later. (This heuristic is not always a win.)
1128
         * It is not necessary to compare scan[2] and match[2] since they
1129
         * are always equal when the other bytes match, given that
1130
         * the hash keys are equal and that HASH_BITS >= 8.
1131
         */
1132
        scan += 2, match++;
1133
        Assert(*scan == *match, "match[2]?");
1134
 
1135
        /* We check for insufficient lookahead only every 8th comparison;
1136
         * the 256th check will be made at strstart+258.
1137
         */
1138
        do {
1139
        } while (*++scan == *++match && *++scan == *++match &&
1140
                 *++scan == *++match && *++scan == *++match &&
1141
                 *++scan == *++match && *++scan == *++match &&
1142
                 *++scan == *++match && *++scan == *++match &&
1143
                 scan < strend);
1144
 
1145
        Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1146
 
1147
        len = MAX_MATCH - (int)(strend - scan);
1148
        scan = strend - MAX_MATCH;
1149
 
1150
#endif /* UNALIGNED_OK */
1151
 
1152
        if (len > best_len) {
1153
            s->match_start = cur_match;
1154
            best_len = len;
1155
            if (len >= nice_match) break;
1156
#ifdef UNALIGNED_OK
1157
            scan_end = *(ushf*)(scan+best_len-1);
1158
#else
1159
            scan_end1  = scan[best_len-1];
1160
            scan_end   = scan[best_len];
1161
#endif
1162
        }
1163
    } while ((cur_match = prev[cur_match & wmask]) > limit
1164
             && --chain_length != 0);
1165
 
1166
    if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
1167
    return s->lookahead;
1168
}
1169
#endif /* ASMV */
1170
#endif /* FASTEST */
1171
 
1172
/* ---------------------------------------------------------------------------
1173
 * Optimized version for level == 1 or strategy == Z_RLE only
1174
 */
1175
local uInt longest_match_fast(s, cur_match)
1176
    deflate_state *s;
1177
    IPos cur_match;                             /* current match */
1178
{
1179
    register Bytef *scan = s->window + s->strstart; /* current string */
1180
    register Bytef *match;                       /* matched string */
1181
    register int len;                           /* length of current match */
1182
    register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1183
 
1184
    /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1185
     * It is easy to get rid of this optimization if necessary.
1186
     */
1187
    Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1188
 
1189
    Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1190
 
1191
    Assert(cur_match < s->strstart, "no future");
1192
 
1193
    match = s->window + cur_match;
1194
 
1195
    /* Return failure if the match length is less than 2:
1196
     */
1197
    if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
1198
 
1199
    /* The check at best_len-1 can be removed because it will be made
1200
     * again later. (This heuristic is not always a win.)
1201
     * It is not necessary to compare scan[2] and match[2] since they
1202
     * are always equal when the other bytes match, given that
1203
     * the hash keys are equal and that HASH_BITS >= 8.
1204
     */
1205
    scan += 2, match += 2;
1206
    Assert(*scan == *match, "match[2]?");
1207
 
1208
    /* We check for insufficient lookahead only every 8th comparison;
1209
     * the 256th check will be made at strstart+258.
1210
     */
1211
    do {
1212
    } while (*++scan == *++match && *++scan == *++match &&
1213
             *++scan == *++match && *++scan == *++match &&
1214
             *++scan == *++match && *++scan == *++match &&
1215
             *++scan == *++match && *++scan == *++match &&
1216
             scan < strend);
1217
 
1218
    Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1219
 
1220
    len = MAX_MATCH - (int)(strend - scan);
1221
 
1222
    if (len < MIN_MATCH) return MIN_MATCH - 1;
1223
 
1224
    s->match_start = cur_match;
1225
    return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
1226
}
1227
 
1228
#ifdef DEBUG
1229
/* ===========================================================================
1230
 * Check that the match at match_start is indeed a match.
1231
 */
1232
local void check_match(s, start, match, length)
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)
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)
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)
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)
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)
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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