1: /* deflate.c -- compress data using the deflation algorithm
2: * Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler
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 1.1.1.1 2012/02/21 16:23:02 misho Exp $ */
51:
52: #include "deflate.h"
53:
54: const char deflate_copyright[] =
55: " deflate 1.2.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler ";
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 block_state deflate_rle OF((deflate_state *s, int flush));
83: local block_state deflate_huff OF((deflate_state *s, int flush));
84: local void lm_init OF((deflate_state *s));
85: local void putShortMSB OF((deflate_state *s, uInt b));
86: local void flush_pending OF((z_streamp strm));
87: local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
88: #ifdef ASMV
89: void match_init OF((void)); /* asm code initialization */
90: uInt longest_match OF((deflate_state *s, IPos cur_match));
91: #else
92: local uInt longest_match OF((deflate_state *s, IPos cur_match));
93: #endif
94:
95: #ifdef DEBUG
96: local void check_match OF((deflate_state *s, IPos start, IPos match,
97: int length));
98: #endif
99:
100: /* ===========================================================================
101: * Local data
102: */
103:
104: #define NIL 0
105: /* Tail of hash chains */
106:
107: #ifndef TOO_FAR
108: # define TOO_FAR 4096
109: #endif
110: /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
111:
112: /* Values for max_lazy_match, good_match and max_chain_length, depending on
113: * the desired pack level (0..9). The values given below have been tuned to
114: * exclude worst case performance for pathological files. Better values may be
115: * found for specific files.
116: */
117: typedef struct config_s {
118: ush good_length; /* reduce lazy search above this match length */
119: ush max_lazy; /* do not perform lazy search above this match length */
120: ush nice_length; /* quit search above this match length */
121: ush max_chain;
122: compress_func func;
123: } config;
124:
125: #ifdef FASTEST
126: local const config configuration_table[2] = {
127: /* good lazy nice chain */
128: /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
129: /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
130: #else
131: local const config configuration_table[10] = {
132: /* good lazy nice chain */
133: /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
134: /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
135: /* 2 */ {4, 5, 16, 8, deflate_fast},
136: /* 3 */ {4, 6, 32, 32, deflate_fast},
137:
138: /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
139: /* 5 */ {8, 16, 32, 32, deflate_slow},
140: /* 6 */ {8, 16, 128, 128, deflate_slow},
141: /* 7 */ {8, 32, 128, 256, deflate_slow},
142: /* 8 */ {32, 128, 258, 1024, deflate_slow},
143: /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
144: #endif
145:
146: /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
147: * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
148: * meaning.
149: */
150:
151: #define EQUAL 0
152: /* result of memcmp for equal strings */
153:
154: #ifndef NO_DUMMY_DECL
155: struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
156: #endif
157:
158: /* ===========================================================================
159: * Update a hash value with the given input byte
160: * IN assertion: all calls to to UPDATE_HASH are made with consecutive
161: * input characters, so that a running hash key can be computed from the
162: * previous key instead of complete recalculation each time.
163: */
164: #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
165:
166:
167: /* ===========================================================================
168: * Insert string str in the dictionary and set match_head to the previous head
169: * of the hash chain (the most recent string with same hash key). Return
170: * the previous length of the hash chain.
171: * If this file is compiled with -DFASTEST, the compression level is forced
172: * to 1, and no hash chains are maintained.
173: * IN assertion: all calls to to INSERT_STRING are made with consecutive
174: * input characters and the first MIN_MATCH bytes of str are valid
175: * (except for the last MIN_MATCH-1 bytes of the input file).
176: */
177: #ifdef FASTEST
178: #define INSERT_STRING(s, str, match_head) \
179: (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
180: match_head = s->head[s->ins_h], \
181: s->head[s->ins_h] = (Pos)(str))
182: #else
183: #define INSERT_STRING(s, str, match_head) \
184: (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
185: match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
186: s->head[s->ins_h] = (Pos)(str))
187: #endif
188:
189: /* ===========================================================================
190: * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
191: * prev[] will be initialized on the fly.
192: */
193: #define CLEAR_HASH(s) \
194: s->head[s->hash_size-1] = NIL; \
195: zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
196:
197: /* ========================================================================= */
198: int ZEXPORT deflateInit_(strm, level, version, stream_size)
199: z_streamp strm;
200: int level;
201: const char *version;
202: int stream_size;
203: {
204: return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
205: Z_DEFAULT_STRATEGY, version, stream_size);
206: /* To do: ignore strm->next_in if we use it as window */
207: }
208:
209: /* ========================================================================= */
210: int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
211: version, stream_size)
212: z_streamp strm;
213: int level;
214: int method;
215: int windowBits;
216: int memLevel;
217: int strategy;
218: const char *version;
219: int stream_size;
220: {
221: deflate_state *s;
222: int wrap = 1;
223: static const char my_version[] = ZLIB_VERSION;
224:
225: ushf *overlay;
226: /* We overlay pending_buf and d_buf+l_buf. This works since the average
227: * output size for (length,distance) codes is <= 24 bits.
228: */
229:
230: if (version == Z_NULL || version[0] != my_version[0] ||
231: stream_size != sizeof(z_stream)) {
232: return Z_VERSION_ERROR;
233: }
234: if (strm == Z_NULL) return Z_STREAM_ERROR;
235:
236: strm->msg = Z_NULL;
237: if (strm->zalloc == (alloc_func)0) {
238: strm->zalloc = zcalloc;
239: strm->opaque = (voidpf)0;
240: }
241: if (strm->zfree == (free_func)0) strm->zfree = zcfree;
242:
243: #ifdef FASTEST
244: if (level != 0) level = 1;
245: #else
246: if (level == Z_DEFAULT_COMPRESSION) level = 6;
247: #endif
248:
249: if (windowBits < 0) { /* suppress zlib wrapper */
250: wrap = 0;
251: windowBits = -windowBits;
252: }
253: #ifdef GZIP
254: else if (windowBits > 15) {
255: wrap = 2; /* write gzip wrapper instead */
256: windowBits -= 16;
257: }
258: #endif
259: if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
260: windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
261: strategy < 0 || strategy > Z_FIXED) {
262: return Z_STREAM_ERROR;
263: }
264: if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
265: s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
266: if (s == Z_NULL) return Z_MEM_ERROR;
267: strm->state = (struct internal_state FAR *)s;
268: s->strm = strm;
269:
270: s->wrap = wrap;
271: s->gzhead = Z_NULL;
272: s->w_bits = windowBits;
273: s->w_size = 1 << s->w_bits;
274: s->w_mask = s->w_size - 1;
275:
276: s->hash_bits = memLevel + 7;
277: s->hash_size = 1 << s->hash_bits;
278: s->hash_mask = s->hash_size - 1;
279: s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
280:
281: s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
282: s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
283: s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
284:
285: s->high_water = 0; /* nothing written to s->window yet */
286:
287: s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
288:
289: overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
290: s->pending_buf = (uchf *) overlay;
291: s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
292:
293: if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
294: s->pending_buf == Z_NULL) {
295: s->status = FINISH_STATE;
296: strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
297: deflateEnd (strm);
298: return Z_MEM_ERROR;
299: }
300: s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
301: s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
302:
303: s->level = level;
304: s->strategy = strategy;
305: s->method = (Byte)method;
306:
307: return deflateReset(strm);
308: }
309:
310: /* ========================================================================= */
311: int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
312: z_streamp strm;
313: const Bytef *dictionary;
314: uInt dictLength;
315: {
316: deflate_state *s;
317: uInt length = dictLength;
318: uInt n;
319: IPos hash_head = 0;
320:
321: if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
322: strm->state->wrap == 2 ||
323: (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
324: return Z_STREAM_ERROR;
325:
326: s = strm->state;
327: if (s->wrap)
328: strm->adler = adler32(strm->adler, dictionary, dictLength);
329:
330: if (length < MIN_MATCH) return Z_OK;
331: if (length > s->w_size) {
332: length = s->w_size;
333: dictionary += dictLength - length; /* use the tail of the dictionary */
334: }
335: zmemcpy(s->window, dictionary, length);
336: s->strstart = length;
337: s->block_start = (long)length;
338:
339: /* Insert all strings in the hash table (except for the last two bytes).
340: * s->lookahead stays null, so s->ins_h will be recomputed at the next
341: * call of fill_window.
342: */
343: s->ins_h = s->window[0];
344: UPDATE_HASH(s, s->ins_h, s->window[1]);
345: for (n = 0; n <= length - MIN_MATCH; n++) {
346: INSERT_STRING(s, n, hash_head);
347: }
348: if (hash_head) hash_head = 0; /* to make compiler happy */
349: return Z_OK;
350: }
351:
352: /* ========================================================================= */
353: int ZEXPORT deflateReset (strm)
354: z_streamp strm;
355: {
356: deflate_state *s;
357:
358: if (strm == Z_NULL || strm->state == Z_NULL ||
359: strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
360: return Z_STREAM_ERROR;
361: }
362:
363: strm->total_in = strm->total_out = 0;
364: strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
365: strm->data_type = Z_UNKNOWN;
366:
367: s = (deflate_state *)strm->state;
368: s->pending = 0;
369: s->pending_out = s->pending_buf;
370:
371: if (s->wrap < 0) {
372: s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
373: }
374: s->status = s->wrap ? INIT_STATE : BUSY_STATE;
375: strm->adler =
376: #ifdef GZIP
377: s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
378: #endif
379: adler32(0L, Z_NULL, 0);
380: s->last_flush = Z_NO_FLUSH;
381:
382: _tr_init(s);
383: lm_init(s);
384:
385: return Z_OK;
386: }
387:
388: /* ========================================================================= */
389: int ZEXPORT deflateSetHeader (strm, head)
390: z_streamp strm;
391: gz_headerp head;
392: {
393: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
394: if (strm->state->wrap != 2) return Z_STREAM_ERROR;
395: strm->state->gzhead = head;
396: return Z_OK;
397: }
398:
399: /* ========================================================================= */
400: int ZEXPORT deflatePrime (strm, bits, value)
401: z_streamp strm;
402: int bits;
403: int value;
404: {
405: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
406: strm->state->bi_valid = bits;
407: strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
408: return Z_OK;
409: }
410:
411: /* ========================================================================= */
412: int ZEXPORT deflateParams(strm, level, strategy)
413: z_streamp strm;
414: int level;
415: int strategy;
416: {
417: deflate_state *s;
418: compress_func func;
419: int err = Z_OK;
420:
421: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
422: s = strm->state;
423:
424: #ifdef FASTEST
425: if (level != 0) level = 1;
426: #else
427: if (level == Z_DEFAULT_COMPRESSION) level = 6;
428: #endif
429: if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
430: return Z_STREAM_ERROR;
431: }
432: func = configuration_table[s->level].func;
433:
434: if ((strategy != s->strategy || func != configuration_table[level].func) &&
435: strm->total_in != 0) {
436: /* Flush the last buffer: */
437: err = deflate(strm, Z_BLOCK);
438: }
439: if (s->level != level) {
440: s->level = level;
441: s->max_lazy_match = configuration_table[level].max_lazy;
442: s->good_match = configuration_table[level].good_length;
443: s->nice_match = configuration_table[level].nice_length;
444: s->max_chain_length = configuration_table[level].max_chain;
445: }
446: s->strategy = strategy;
447: return err;
448: }
449:
450: /* ========================================================================= */
451: int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
452: z_streamp strm;
453: int good_length;
454: int max_lazy;
455: int nice_length;
456: int max_chain;
457: {
458: deflate_state *s;
459:
460: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
461: s = strm->state;
462: s->good_match = good_length;
463: s->max_lazy_match = max_lazy;
464: s->nice_match = nice_length;
465: s->max_chain_length = max_chain;
466: return Z_OK;
467: }
468:
469: /* =========================================================================
470: * For the default windowBits of 15 and memLevel of 8, this function returns
471: * a close to exact, as well as small, upper bound on the compressed size.
472: * They are coded as constants here for a reason--if the #define's are
473: * changed, then this function needs to be changed as well. The return
474: * value for 15 and 8 only works for those exact settings.
475: *
476: * For any setting other than those defaults for windowBits and memLevel,
477: * the value returned is a conservative worst case for the maximum expansion
478: * resulting from using fixed blocks instead of stored blocks, which deflate
479: * can emit on compressed data for some combinations of the parameters.
480: *
481: * This function could be more sophisticated to provide closer upper bounds for
482: * every combination of windowBits and memLevel. But even the conservative
483: * upper bound of about 14% expansion does not seem onerous for output buffer
484: * allocation.
485: */
486: uLong ZEXPORT deflateBound(strm, sourceLen)
487: z_streamp strm;
488: uLong sourceLen;
489: {
490: deflate_state *s;
491: uLong complen, wraplen;
492: Bytef *str;
493:
494: /* conservative upper bound for compressed data */
495: complen = sourceLen +
496: ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
497:
498: /* if can't get parameters, return conservative bound plus zlib wrapper */
499: if (strm == Z_NULL || strm->state == Z_NULL)
500: return complen + 6;
501:
502: /* compute wrapper length */
503: s = strm->state;
504: switch (s->wrap) {
505: case 0: /* raw deflate */
506: wraplen = 0;
507: break;
508: case 1: /* zlib wrapper */
509: wraplen = 6 + (s->strstart ? 4 : 0);
510: break;
511: case 2: /* gzip wrapper */
512: wraplen = 18;
513: if (s->gzhead != Z_NULL) { /* user-supplied gzip header */
514: if (s->gzhead->extra != Z_NULL)
515: wraplen += 2 + s->gzhead->extra_len;
516: str = s->gzhead->name;
517: if (str != Z_NULL)
518: do {
519: wraplen++;
520: } while (*str++);
521: str = s->gzhead->comment;
522: if (str != Z_NULL)
523: do {
524: wraplen++;
525: } while (*str++);
526: if (s->gzhead->hcrc)
527: wraplen += 2;
528: }
529: break;
530: default: /* for compiler happiness */
531: wraplen = 6;
532: }
533:
534: /* if not default parameters, return conservative bound */
535: if (s->w_bits != 15 || s->hash_bits != 8 + 7)
536: return complen + wraplen;
537:
538: /* default settings: return tight bound for that case */
539: return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
540: (sourceLen >> 25) + 13 - 6 + wraplen;
541: }
542:
543: /* =========================================================================
544: * Put a short in the pending buffer. The 16-bit value is put in MSB order.
545: * IN assertion: the stream state is correct and there is enough room in
546: * pending_buf.
547: */
548: local void putShortMSB (s, b)
549: deflate_state *s;
550: uInt b;
551: {
552: put_byte(s, (Byte)(b >> 8));
553: put_byte(s, (Byte)(b & 0xff));
554: }
555:
556: /* =========================================================================
557: * Flush as much pending output as possible. All deflate() output goes
558: * through this function so some applications may wish to modify it
559: * to avoid allocating a large strm->next_out buffer and copying into it.
560: * (See also read_buf()).
561: */
562: local void flush_pending(strm)
563: z_streamp strm;
564: {
565: unsigned len = strm->state->pending;
566:
567: if (len > strm->avail_out) len = strm->avail_out;
568: if (len == 0) return;
569:
570: zmemcpy(strm->next_out, strm->state->pending_out, len);
571: strm->next_out += len;
572: strm->state->pending_out += len;
573: strm->total_out += len;
574: strm->avail_out -= len;
575: strm->state->pending -= len;
576: if (strm->state->pending == 0) {
577: strm->state->pending_out = strm->state->pending_buf;
578: }
579: }
580:
581: /* ========================================================================= */
582: int ZEXPORT deflate (strm, flush)
583: z_streamp strm;
584: int flush;
585: {
586: int old_flush; /* value of flush param for previous deflate call */
587: deflate_state *s;
588:
589: if (strm == Z_NULL || strm->state == Z_NULL ||
590: flush > Z_BLOCK || flush < 0) {
591: return Z_STREAM_ERROR;
592: }
593: s = strm->state;
594:
595: if (strm->next_out == Z_NULL ||
596: (strm->next_in == Z_NULL && strm->avail_in != 0) ||
597: (s->status == FINISH_STATE && flush != Z_FINISH)) {
598: ERR_RETURN(strm, Z_STREAM_ERROR);
599: }
600: if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
601:
602: s->strm = strm; /* just in case */
603: old_flush = s->last_flush;
604: s->last_flush = flush;
605:
606: /* Write the header */
607: if (s->status == INIT_STATE) {
608: #ifdef GZIP
609: if (s->wrap == 2) {
610: strm->adler = crc32(0L, Z_NULL, 0);
611: put_byte(s, 31);
612: put_byte(s, 139);
613: put_byte(s, 8);
614: if (s->gzhead == Z_NULL) {
615: put_byte(s, 0);
616: put_byte(s, 0);
617: put_byte(s, 0);
618: put_byte(s, 0);
619: put_byte(s, 0);
620: put_byte(s, s->level == 9 ? 2 :
621: (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
622: 4 : 0));
623: put_byte(s, OS_CODE);
624: s->status = BUSY_STATE;
625: }
626: else {
627: put_byte(s, (s->gzhead->text ? 1 : 0) +
628: (s->gzhead->hcrc ? 2 : 0) +
629: (s->gzhead->extra == Z_NULL ? 0 : 4) +
630: (s->gzhead->name == Z_NULL ? 0 : 8) +
631: (s->gzhead->comment == Z_NULL ? 0 : 16)
632: );
633: put_byte(s, (Byte)(s->gzhead->time & 0xff));
634: put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
635: put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
636: put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
637: put_byte(s, s->level == 9 ? 2 :
638: (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
639: 4 : 0));
640: put_byte(s, s->gzhead->os & 0xff);
641: if (s->gzhead->extra != Z_NULL) {
642: put_byte(s, s->gzhead->extra_len & 0xff);
643: put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
644: }
645: if (s->gzhead->hcrc)
646: strm->adler = crc32(strm->adler, s->pending_buf,
647: s->pending);
648: s->gzindex = 0;
649: s->status = EXTRA_STATE;
650: }
651: }
652: else
653: #endif
654: {
655: uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
656: uInt level_flags;
657:
658: if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
659: level_flags = 0;
660: else if (s->level < 6)
661: level_flags = 1;
662: else if (s->level == 6)
663: level_flags = 2;
664: else
665: level_flags = 3;
666: header |= (level_flags << 6);
667: if (s->strstart != 0) header |= PRESET_DICT;
668: header += 31 - (header % 31);
669:
670: s->status = BUSY_STATE;
671: putShortMSB(s, header);
672:
673: /* Save the adler32 of the preset dictionary: */
674: if (s->strstart != 0) {
675: putShortMSB(s, (uInt)(strm->adler >> 16));
676: putShortMSB(s, (uInt)(strm->adler & 0xffff));
677: }
678: strm->adler = adler32(0L, Z_NULL, 0);
679: }
680: }
681: #ifdef GZIP
682: if (s->status == EXTRA_STATE) {
683: if (s->gzhead->extra != Z_NULL) {
684: uInt beg = s->pending; /* start of bytes to update crc */
685:
686: while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
687: if (s->pending == s->pending_buf_size) {
688: if (s->gzhead->hcrc && s->pending > beg)
689: strm->adler = crc32(strm->adler, s->pending_buf + beg,
690: s->pending - beg);
691: flush_pending(strm);
692: beg = s->pending;
693: if (s->pending == s->pending_buf_size)
694: break;
695: }
696: put_byte(s, s->gzhead->extra[s->gzindex]);
697: s->gzindex++;
698: }
699: if (s->gzhead->hcrc && s->pending > beg)
700: strm->adler = crc32(strm->adler, s->pending_buf + beg,
701: s->pending - beg);
702: if (s->gzindex == s->gzhead->extra_len) {
703: s->gzindex = 0;
704: s->status = NAME_STATE;
705: }
706: }
707: else
708: s->status = NAME_STATE;
709: }
710: if (s->status == NAME_STATE) {
711: if (s->gzhead->name != Z_NULL) {
712: uInt beg = s->pending; /* start of bytes to update crc */
713: int val;
714:
715: do {
716: if (s->pending == s->pending_buf_size) {
717: if (s->gzhead->hcrc && s->pending > beg)
718: strm->adler = crc32(strm->adler, s->pending_buf + beg,
719: s->pending - beg);
720: flush_pending(strm);
721: beg = s->pending;
722: if (s->pending == s->pending_buf_size) {
723: val = 1;
724: break;
725: }
726: }
727: val = s->gzhead->name[s->gzindex++];
728: put_byte(s, val);
729: } while (val != 0);
730: if (s->gzhead->hcrc && s->pending > beg)
731: strm->adler = crc32(strm->adler, s->pending_buf + beg,
732: s->pending - beg);
733: if (val == 0) {
734: s->gzindex = 0;
735: s->status = COMMENT_STATE;
736: }
737: }
738: else
739: s->status = COMMENT_STATE;
740: }
741: if (s->status == COMMENT_STATE) {
742: if (s->gzhead->comment != Z_NULL) {
743: uInt beg = s->pending; /* start of bytes to update crc */
744: int val;
745:
746: do {
747: if (s->pending == s->pending_buf_size) {
748: if (s->gzhead->hcrc && s->pending > beg)
749: strm->adler = crc32(strm->adler, s->pending_buf + beg,
750: s->pending - beg);
751: flush_pending(strm);
752: beg = s->pending;
753: if (s->pending == s->pending_buf_size) {
754: val = 1;
755: break;
756: }
757: }
758: val = s->gzhead->comment[s->gzindex++];
759: put_byte(s, val);
760: } while (val != 0);
761: if (s->gzhead->hcrc && s->pending > beg)
762: strm->adler = crc32(strm->adler, s->pending_buf + beg,
763: s->pending - beg);
764: if (val == 0)
765: s->status = HCRC_STATE;
766: }
767: else
768: s->status = HCRC_STATE;
769: }
770: if (s->status == HCRC_STATE) {
771: if (s->gzhead->hcrc) {
772: if (s->pending + 2 > s->pending_buf_size)
773: flush_pending(strm);
774: if (s->pending + 2 <= s->pending_buf_size) {
775: put_byte(s, (Byte)(strm->adler & 0xff));
776: put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
777: strm->adler = crc32(0L, Z_NULL, 0);
778: s->status = BUSY_STATE;
779: }
780: }
781: else
782: s->status = BUSY_STATE;
783: }
784: #endif
785:
786: /* Flush as much pending output as possible */
787: if (s->pending != 0) {
788: flush_pending(strm);
789: if (strm->avail_out == 0) {
790: /* Since avail_out is 0, deflate will be called again with
791: * more output space, but possibly with both pending and
792: * avail_in equal to zero. There won't be anything to do,
793: * but this is not an error situation so make sure we
794: * return OK instead of BUF_ERROR at next call of deflate:
795: */
796: s->last_flush = -1;
797: return Z_OK;
798: }
799:
800: /* Make sure there is something to do and avoid duplicate consecutive
801: * flushes. For repeated and useless calls with Z_FINISH, we keep
802: * returning Z_STREAM_END instead of Z_BUF_ERROR.
803: */
804: } else if (strm->avail_in == 0 && flush <= old_flush &&
805: flush != Z_FINISH) {
806: ERR_RETURN(strm, Z_BUF_ERROR);
807: }
808:
809: /* User must not provide more input after the first FINISH: */
810: if (s->status == FINISH_STATE && strm->avail_in != 0) {
811: ERR_RETURN(strm, Z_BUF_ERROR);
812: }
813:
814: /* Start a new block or continue the current one.
815: */
816: if (strm->avail_in != 0 || s->lookahead != 0 ||
817: (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
818: block_state bstate;
819:
820: bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
821: (s->strategy == Z_RLE ? deflate_rle(s, flush) :
822: (*(configuration_table[s->level].func))(s, flush));
823:
824: if (bstate == finish_started || bstate == finish_done) {
825: s->status = FINISH_STATE;
826: }
827: if (bstate == need_more || bstate == finish_started) {
828: if (strm->avail_out == 0) {
829: s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
830: }
831: return Z_OK;
832: /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
833: * of deflate should use the same flush parameter to make sure
834: * that the flush is complete. So we don't have to output an
835: * empty block here, this will be done at next call. This also
836: * ensures that for a very small output buffer, we emit at most
837: * one empty block.
838: */
839: }
840: if (bstate == block_done) {
841: if (flush == Z_PARTIAL_FLUSH) {
842: _tr_align(s);
843: } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
844: _tr_stored_block(s, (char*)0, 0L, 0);
845: /* For a full flush, this empty block will be recognized
846: * as a special marker by inflate_sync().
847: */
848: if (flush == Z_FULL_FLUSH) {
849: CLEAR_HASH(s); /* forget history */
850: if (s->lookahead == 0) {
851: s->strstart = 0;
852: s->block_start = 0L;
853: }
854: }
855: }
856: flush_pending(strm);
857: if (strm->avail_out == 0) {
858: s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
859: return Z_OK;
860: }
861: }
862: }
863: Assert(strm->avail_out > 0, "bug2");
864:
865: if (flush != Z_FINISH) return Z_OK;
866: if (s->wrap <= 0) return Z_STREAM_END;
867:
868: /* Write the trailer */
869: #ifdef GZIP
870: if (s->wrap == 2) {
871: put_byte(s, (Byte)(strm->adler & 0xff));
872: put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
873: put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
874: put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
875: put_byte(s, (Byte)(strm->total_in & 0xff));
876: put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
877: put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
878: put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
879: }
880: else
881: #endif
882: {
883: putShortMSB(s, (uInt)(strm->adler >> 16));
884: putShortMSB(s, (uInt)(strm->adler & 0xffff));
885: }
886: flush_pending(strm);
887: /* If avail_out is zero, the application will call deflate again
888: * to flush the rest.
889: */
890: if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
891: return s->pending != 0 ? Z_OK : Z_STREAM_END;
892: }
893:
894: /* ========================================================================= */
895: int ZEXPORT deflateEnd (strm)
896: z_streamp strm;
897: {
898: int status;
899:
900: if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
901:
902: status = strm->state->status;
903: if (status != INIT_STATE &&
904: status != EXTRA_STATE &&
905: status != NAME_STATE &&
906: status != COMMENT_STATE &&
907: status != HCRC_STATE &&
908: status != BUSY_STATE &&
909: status != FINISH_STATE) {
910: return Z_STREAM_ERROR;
911: }
912:
913: /* Deallocate in reverse order of allocations: */
914: TRY_FREE(strm, strm->state->pending_buf);
915: TRY_FREE(strm, strm->state->head);
916: TRY_FREE(strm, strm->state->prev);
917: TRY_FREE(strm, strm->state->window);
918:
919: ZFREE(strm, strm->state);
920: strm->state = Z_NULL;
921:
922: return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
923: }
924:
925: /* =========================================================================
926: * Copy the source state to the destination state.
927: * To simplify the source, this is not supported for 16-bit MSDOS (which
928: * doesn't have enough memory anyway to duplicate compression states).
929: */
930: int ZEXPORT deflateCopy (dest, source)
931: z_streamp dest;
932: z_streamp source;
933: {
934: #ifdef MAXSEG_64K
935: return Z_STREAM_ERROR;
936: #else
937: deflate_state *ds;
938: deflate_state *ss;
939: ushf *overlay;
940:
941:
942: if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
943: return Z_STREAM_ERROR;
944: }
945:
946: ss = source->state;
947:
948: zmemcpy(dest, source, sizeof(z_stream));
949:
950: ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
951: if (ds == Z_NULL) return Z_MEM_ERROR;
952: dest->state = (struct internal_state FAR *) ds;
953: zmemcpy(ds, ss, sizeof(deflate_state));
954: ds->strm = dest;
955:
956: ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
957: ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
958: ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
959: overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
960: ds->pending_buf = (uchf *) overlay;
961:
962: if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
963: ds->pending_buf == Z_NULL) {
964: deflateEnd (dest);
965: return Z_MEM_ERROR;
966: }
967: /* following zmemcpy do not work for 16-bit MSDOS */
968: zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
969: zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
970: zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
971: zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
972:
973: ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
974: ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
975: ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
976:
977: ds->l_desc.dyn_tree = ds->dyn_ltree;
978: ds->d_desc.dyn_tree = ds->dyn_dtree;
979: ds->bl_desc.dyn_tree = ds->bl_tree;
980:
981: return Z_OK;
982: #endif /* MAXSEG_64K */
983: }
984:
985: /* ===========================================================================
986: * Read a new buffer from the current input stream, update the adler32
987: * and total number of bytes read. All deflate() input goes through
988: * this function so some applications may wish to modify it to avoid
989: * allocating a large strm->next_in buffer and copying from it.
990: * (See also flush_pending()).
991: */
992: local int read_buf(strm, buf, size)
993: z_streamp strm;
994: Bytef *buf;
995: unsigned size;
996: {
997: unsigned len = strm->avail_in;
998:
999: if (len > size) len = size;
1000: if (len == 0) return 0;
1001:
1002: strm->avail_in -= len;
1003:
1004: if (strm->state->wrap == 1) {
1005: strm->adler = adler32(strm->adler, strm->next_in, len);
1006: }
1007: #ifdef GZIP
1008: else if (strm->state->wrap == 2) {
1009: strm->adler = crc32(strm->adler, strm->next_in, len);
1010: }
1011: #endif
1012: zmemcpy(buf, strm->next_in, len);
1013: strm->next_in += len;
1014: strm->total_in += len;
1015:
1016: return (int)len;
1017: }
1018:
1019: /* ===========================================================================
1020: * Initialize the "longest match" routines for a new zlib stream
1021: */
1022: local void lm_init (s)
1023: deflate_state *s;
1024: {
1025: s->window_size = (ulg)2L*s->w_size;
1026:
1027: CLEAR_HASH(s);
1028:
1029: /* Set the default configuration parameters:
1030: */
1031: s->max_lazy_match = configuration_table[s->level].max_lazy;
1032: s->good_match = configuration_table[s->level].good_length;
1033: s->nice_match = configuration_table[s->level].nice_length;
1034: s->max_chain_length = configuration_table[s->level].max_chain;
1035:
1036: s->strstart = 0;
1037: s->block_start = 0L;
1038: s->lookahead = 0;
1039: s->match_length = s->prev_length = MIN_MATCH-1;
1040: s->match_available = 0;
1041: s->ins_h = 0;
1042: #ifndef FASTEST
1043: #ifdef ASMV
1044: match_init(); /* initialize the asm code */
1045: #endif
1046: #endif
1047: }
1048:
1049: #ifndef FASTEST
1050: /* ===========================================================================
1051: * Set match_start to the longest match starting at the given string and
1052: * return its length. Matches shorter or equal to prev_length are discarded,
1053: * in which case the result is equal to prev_length and match_start is
1054: * garbage.
1055: * IN assertions: cur_match is the head of the hash chain for the current
1056: * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
1057: * OUT assertion: the match length is not greater than s->lookahead.
1058: */
1059: #ifndef ASMV
1060: /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
1061: * match.S. The code will be functionally equivalent.
1062: */
1063: local uInt longest_match(s, cur_match)
1064: deflate_state *s;
1065: IPos cur_match; /* current match */
1066: {
1067: unsigned chain_length = s->max_chain_length;/* max hash chain length */
1068: register Bytef *scan = s->window + s->strstart; /* current string */
1069: register Bytef *match; /* matched string */
1070: register int len; /* length of current match */
1071: int best_len = s->prev_length; /* best match length so far */
1072: int nice_match = s->nice_match; /* stop if match long enough */
1073: IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
1074: s->strstart - (IPos)MAX_DIST(s) : NIL;
1075: /* Stop when cur_match becomes <= limit. To simplify the code,
1076: * we prevent matches with the string of window index 0.
1077: */
1078: Posf *prev = s->prev;
1079: uInt wmask = s->w_mask;
1080:
1081: #ifdef UNALIGNED_OK
1082: /* Compare two bytes at a time. Note: this is not always beneficial.
1083: * Try with and without -DUNALIGNED_OK to check.
1084: */
1085: register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
1086: register ush scan_start = *(ushf*)scan;
1087: register ush scan_end = *(ushf*)(scan+best_len-1);
1088: #else
1089: register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1090: register Byte scan_end1 = scan[best_len-1];
1091: register Byte scan_end = scan[best_len];
1092: #endif
1093:
1094: /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1095: * It is easy to get rid of this optimization if necessary.
1096: */
1097: Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1098:
1099: /* Do not waste too much time if we already have a good match: */
1100: if (s->prev_length >= s->good_match) {
1101: chain_length >>= 2;
1102: }
1103: /* Do not look for matches beyond the end of the input. This is necessary
1104: * to make deflate deterministic.
1105: */
1106: if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
1107:
1108: Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1109:
1110: do {
1111: Assert(cur_match < s->strstart, "no future");
1112: match = s->window + cur_match;
1113:
1114: /* Skip to next match if the match length cannot increase
1115: * or if the match length is less than 2. Note that the checks below
1116: * for insufficient lookahead only occur occasionally for performance
1117: * reasons. Therefore uninitialized memory will be accessed, and
1118: * conditional jumps will be made that depend on those values.
1119: * However the length of the match is limited to the lookahead, so
1120: * the output of deflate is not affected by the uninitialized values.
1121: */
1122: #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
1123: /* This code assumes sizeof(unsigned short) == 2. Do not use
1124: * UNALIGNED_OK if your compiler uses a different size.
1125: */
1126: if (*(ushf*)(match+best_len-1) != scan_end ||
1127: *(ushf*)match != scan_start) continue;
1128:
1129: /* It is not necessary to compare scan[2] and match[2] since they are
1130: * always equal when the other bytes match, given that the hash keys
1131: * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
1132: * strstart+3, +5, ... up to strstart+257. We check for insufficient
1133: * lookahead only every 4th comparison; the 128th check will be made
1134: * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
1135: * necessary to put more guard bytes at the end of the window, or
1136: * to check more often for insufficient lookahead.
1137: */
1138: Assert(scan[2] == match[2], "scan[2]?");
1139: scan++, match++;
1140: do {
1141: } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1142: *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1143: *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1144: *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
1145: scan < strend);
1146: /* The funny "do {}" generates better code on most compilers */
1147:
1148: /* Here, scan <= window+strstart+257 */
1149: Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1150: if (*scan == *match) scan++;
1151:
1152: len = (MAX_MATCH - 1) - (int)(strend-scan);
1153: scan = strend - (MAX_MATCH-1);
1154:
1155: #else /* UNALIGNED_OK */
1156:
1157: if (match[best_len] != scan_end ||
1158: match[best_len-1] != scan_end1 ||
1159: *match != *scan ||
1160: *++match != scan[1]) continue;
1161:
1162: /* The check at best_len-1 can be removed because it will be made
1163: * again later. (This heuristic is not always a win.)
1164: * It is not necessary to compare scan[2] and match[2] since they
1165: * are always equal when the other bytes match, given that
1166: * the hash keys are equal and that HASH_BITS >= 8.
1167: */
1168: scan += 2, match++;
1169: Assert(*scan == *match, "match[2]?");
1170:
1171: /* We check for insufficient lookahead only every 8th comparison;
1172: * the 256th check will be made at strstart+258.
1173: */
1174: do {
1175: } while (*++scan == *++match && *++scan == *++match &&
1176: *++scan == *++match && *++scan == *++match &&
1177: *++scan == *++match && *++scan == *++match &&
1178: *++scan == *++match && *++scan == *++match &&
1179: scan < strend);
1180:
1181: Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1182:
1183: len = MAX_MATCH - (int)(strend - scan);
1184: scan = strend - MAX_MATCH;
1185:
1186: #endif /* UNALIGNED_OK */
1187:
1188: if (len > best_len) {
1189: s->match_start = cur_match;
1190: best_len = len;
1191: if (len >= nice_match) break;
1192: #ifdef UNALIGNED_OK
1193: scan_end = *(ushf*)(scan+best_len-1);
1194: #else
1195: scan_end1 = scan[best_len-1];
1196: scan_end = scan[best_len];
1197: #endif
1198: }
1199: } while ((cur_match = prev[cur_match & wmask]) > limit
1200: && --chain_length != 0);
1201:
1202: if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
1203: return s->lookahead;
1204: }
1205: #endif /* ASMV */
1206:
1207: #else /* FASTEST */
1208:
1209: /* ---------------------------------------------------------------------------
1210: * Optimized version for FASTEST only
1211: */
1212: local uInt longest_match(s, cur_match)
1213: deflate_state *s;
1214: IPos cur_match; /* current match */
1215: {
1216: register Bytef *scan = s->window + s->strstart; /* current string */
1217: register Bytef *match; /* matched string */
1218: register int len; /* length of current match */
1219: register Bytef *strend = s->window + s->strstart + MAX_MATCH;
1220:
1221: /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
1222: * It is easy to get rid of this optimization if necessary.
1223: */
1224: Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
1225:
1226: Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
1227:
1228: Assert(cur_match < s->strstart, "no future");
1229:
1230: match = s->window + cur_match;
1231:
1232: /* Return failure if the match length is less than 2:
1233: */
1234: if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
1235:
1236: /* The check at best_len-1 can be removed because it will be made
1237: * again later. (This heuristic is not always a win.)
1238: * It is not necessary to compare scan[2] and match[2] since they
1239: * are always equal when the other bytes match, given that
1240: * the hash keys are equal and that HASH_BITS >= 8.
1241: */
1242: scan += 2, match += 2;
1243: Assert(*scan == *match, "match[2]?");
1244:
1245: /* We check for insufficient lookahead only every 8th comparison;
1246: * the 256th check will be made at strstart+258.
1247: */
1248: do {
1249: } while (*++scan == *++match && *++scan == *++match &&
1250: *++scan == *++match && *++scan == *++match &&
1251: *++scan == *++match && *++scan == *++match &&
1252: *++scan == *++match && *++scan == *++match &&
1253: scan < strend);
1254:
1255: Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
1256:
1257: len = MAX_MATCH - (int)(strend - scan);
1258:
1259: if (len < MIN_MATCH) return MIN_MATCH - 1;
1260:
1261: s->match_start = cur_match;
1262: return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
1263: }
1264:
1265: #endif /* FASTEST */
1266:
1267: #ifdef DEBUG
1268: /* ===========================================================================
1269: * Check that the match at match_start is indeed a match.
1270: */
1271: local void check_match(s, start, match, length)
1272: deflate_state *s;
1273: IPos start, match;
1274: int length;
1275: {
1276: /* check that the match is indeed a match */
1277: if (zmemcmp(s->window + match,
1278: s->window + start, length) != EQUAL) {
1279: fprintf(stderr, " start %u, match %u, length %d\n",
1280: start, match, length);
1281: do {
1282: fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
1283: } while (--length != 0);
1284: z_error("invalid match");
1285: }
1286: if (z_verbose > 1) {
1287: fprintf(stderr,"\\[%d,%d]", start-match, length);
1288: do { putc(s->window[start++], stderr); } while (--length != 0);
1289: }
1290: }
1291: #else
1292: # define check_match(s, start, match, length)
1293: #endif /* DEBUG */
1294:
1295: /* ===========================================================================
1296: * Fill the window when the lookahead becomes insufficient.
1297: * Updates strstart and lookahead.
1298: *
1299: * IN assertion: lookahead < MIN_LOOKAHEAD
1300: * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
1301: * At least one byte has been read, or avail_in == 0; reads are
1302: * performed for at least two bytes (required for the zip translate_eol
1303: * option -- not supported here).
1304: */
1305: local void fill_window(s)
1306: deflate_state *s;
1307: {
1308: register unsigned n, m;
1309: register Posf *p;
1310: unsigned more; /* Amount of free space at the end of the window. */
1311: uInt wsize = s->w_size;
1312:
1313: do {
1314: more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
1315:
1316: /* Deal with !@#$% 64K limit: */
1317: if (sizeof(int) <= 2) {
1318: if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
1319: more = wsize;
1320:
1321: } else if (more == (unsigned)(-1)) {
1322: /* Very unlikely, but possible on 16 bit machine if
1323: * strstart == 0 && lookahead == 1 (input done a byte at time)
1324: */
1325: more--;
1326: }
1327: }
1328:
1329: /* If the window is almost full and there is insufficient lookahead,
1330: * move the upper half to the lower one to make room in the upper half.
1331: */
1332: if (s->strstart >= wsize+MAX_DIST(s)) {
1333:
1334: zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
1335: s->match_start -= wsize;
1336: s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
1337: s->block_start -= (long) wsize;
1338:
1339: /* Slide the hash table (could be avoided with 32 bit values
1340: at the expense of memory usage). We slide even when level == 0
1341: to keep the hash table consistent if we switch back to level > 0
1342: later. (Using level 0 permanently is not an optimal usage of
1343: zlib, so we don't care about this pathological case.)
1344: */
1345: n = s->hash_size;
1346: p = &s->head[n];
1347: do {
1348: m = *--p;
1349: *p = (Pos)(m >= wsize ? m-wsize : NIL);
1350: } while (--n);
1351:
1352: n = wsize;
1353: #ifndef FASTEST
1354: p = &s->prev[n];
1355: do {
1356: m = *--p;
1357: *p = (Pos)(m >= wsize ? m-wsize : NIL);
1358: /* If n is not on any hash chain, prev[n] is garbage but
1359: * its value will never be used.
1360: */
1361: } while (--n);
1362: #endif
1363: more += wsize;
1364: }
1365: if (s->strm->avail_in == 0) return;
1366:
1367: /* If there was no sliding:
1368: * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
1369: * more == window_size - lookahead - strstart
1370: * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
1371: * => more >= window_size - 2*WSIZE + 2
1372: * In the BIG_MEM or MMAP case (not yet supported),
1373: * window_size == input_size + MIN_LOOKAHEAD &&
1374: * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
1375: * Otherwise, window_size == 2*WSIZE so more >= 2.
1376: * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
1377: */
1378: Assert(more >= 2, "more < 2");
1379:
1380: n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
1381: s->lookahead += n;
1382:
1383: /* Initialize the hash value now that we have some input: */
1384: if (s->lookahead >= MIN_MATCH) {
1385: s->ins_h = s->window[s->strstart];
1386: UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1387: #if MIN_MATCH != 3
1388: Call UPDATE_HASH() MIN_MATCH-3 more times
1389: #endif
1390: }
1391: /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
1392: * but this is not important since only literal bytes will be emitted.
1393: */
1394:
1395: } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
1396:
1397: /* If the WIN_INIT bytes after the end of the current data have never been
1398: * written, then zero those bytes in order to avoid memory check reports of
1399: * the use of uninitialized (or uninitialised as Julian writes) bytes by
1400: * the longest match routines. Update the high water mark for the next
1401: * time through here. WIN_INIT is set to MAX_MATCH since the longest match
1402: * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
1403: */
1404: if (s->high_water < s->window_size) {
1405: ulg curr = s->strstart + (ulg)(s->lookahead);
1406: ulg init;
1407:
1408: if (s->high_water < curr) {
1409: /* Previous high water mark below current data -- zero WIN_INIT
1410: * bytes or up to end of window, whichever is less.
1411: */
1412: init = s->window_size - curr;
1413: if (init > WIN_INIT)
1414: init = WIN_INIT;
1415: zmemzero(s->window + curr, (unsigned)init);
1416: s->high_water = curr + init;
1417: }
1418: else if (s->high_water < (ulg)curr + WIN_INIT) {
1419: /* High water mark at or above current data, but below current data
1420: * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
1421: * to end of window, whichever is less.
1422: */
1423: init = (ulg)curr + WIN_INIT - s->high_water;
1424: if (init > s->window_size - s->high_water)
1425: init = s->window_size - s->high_water;
1426: zmemzero(s->window + s->high_water, (unsigned)init);
1427: s->high_water += init;
1428: }
1429: }
1430: }
1431:
1432: /* ===========================================================================
1433: * Flush the current block, with given end-of-file flag.
1434: * IN assertion: strstart is set to the end of the current match.
1435: */
1436: #define FLUSH_BLOCK_ONLY(s, last) { \
1437: _tr_flush_block(s, (s->block_start >= 0L ? \
1438: (charf *)&s->window[(unsigned)s->block_start] : \
1439: (charf *)Z_NULL), \
1440: (ulg)((long)s->strstart - s->block_start), \
1441: (last)); \
1442: s->block_start = s->strstart; \
1443: flush_pending(s->strm); \
1444: Tracev((stderr,"[FLUSH]")); \
1445: }
1446:
1447: /* Same but force premature exit if necessary. */
1448: #define FLUSH_BLOCK(s, last) { \
1449: FLUSH_BLOCK_ONLY(s, last); \
1450: if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
1451: }
1452:
1453: /* ===========================================================================
1454: * Copy without compression as much as possible from the input stream, return
1455: * the current block state.
1456: * This function does not insert new strings in the dictionary since
1457: * uncompressible data is probably not useful. This function is used
1458: * only for the level=0 compression option.
1459: * NOTE: this function should be optimized to avoid extra copying from
1460: * window to pending_buf.
1461: */
1462: local block_state deflate_stored(s, flush)
1463: deflate_state *s;
1464: int flush;
1465: {
1466: /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
1467: * to pending_buf_size, and each stored block has a 5 byte header:
1468: */
1469: ulg max_block_size = 0xffff;
1470: ulg max_start;
1471:
1472: if (max_block_size > s->pending_buf_size - 5) {
1473: max_block_size = s->pending_buf_size - 5;
1474: }
1475:
1476: /* Copy as much as possible from input to output: */
1477: for (;;) {
1478: /* Fill the window as much as possible: */
1479: if (s->lookahead <= 1) {
1480:
1481: Assert(s->strstart < s->w_size+MAX_DIST(s) ||
1482: s->block_start >= (long)s->w_size, "slide too late");
1483:
1484: fill_window(s);
1485: if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
1486:
1487: if (s->lookahead == 0) break; /* flush the current block */
1488: }
1489: Assert(s->block_start >= 0L, "block gone");
1490:
1491: s->strstart += s->lookahead;
1492: s->lookahead = 0;
1493:
1494: /* Emit a stored block if pending_buf will be full: */
1495: max_start = s->block_start + max_block_size;
1496: if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
1497: /* strstart == 0 is possible when wraparound on 16-bit machine */
1498: s->lookahead = (uInt)(s->strstart - max_start);
1499: s->strstart = (uInt)max_start;
1500: FLUSH_BLOCK(s, 0);
1501: }
1502: /* Flush if we may have to slide, otherwise block_start may become
1503: * negative and the data will be gone:
1504: */
1505: if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
1506: FLUSH_BLOCK(s, 0);
1507: }
1508: }
1509: FLUSH_BLOCK(s, flush == Z_FINISH);
1510: return flush == Z_FINISH ? finish_done : block_done;
1511: }
1512:
1513: /* ===========================================================================
1514: * Compress as much as possible from the input stream, return the current
1515: * block state.
1516: * This function does not perform lazy evaluation of matches and inserts
1517: * new strings in the dictionary only for unmatched strings or for short
1518: * matches. It is used only for the fast compression options.
1519: */
1520: local block_state deflate_fast(s, flush)
1521: deflate_state *s;
1522: int flush;
1523: {
1524: IPos hash_head; /* head of the hash chain */
1525: int bflush; /* set if current block must be flushed */
1526:
1527: for (;;) {
1528: /* Make sure that we always have enough lookahead, except
1529: * at the end of the input file. We need MAX_MATCH bytes
1530: * for the next match, plus MIN_MATCH bytes to insert the
1531: * string following the next match.
1532: */
1533: if (s->lookahead < MIN_LOOKAHEAD) {
1534: fill_window(s);
1535: if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1536: return need_more;
1537: }
1538: if (s->lookahead == 0) break; /* flush the current block */
1539: }
1540:
1541: /* Insert the string window[strstart .. strstart+2] in the
1542: * dictionary, and set hash_head to the head of the hash chain:
1543: */
1544: hash_head = NIL;
1545: if (s->lookahead >= MIN_MATCH) {
1546: INSERT_STRING(s, s->strstart, hash_head);
1547: }
1548:
1549: /* Find the longest match, discarding those <= prev_length.
1550: * At this point we have always match_length < MIN_MATCH
1551: */
1552: if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
1553: /* To simplify the code, we prevent matches with the string
1554: * of window index 0 (in particular we have to avoid a match
1555: * of the string with itself at the start of the input file).
1556: */
1557: s->match_length = longest_match (s, hash_head);
1558: /* longest_match() sets match_start */
1559: }
1560: if (s->match_length >= MIN_MATCH) {
1561: check_match(s, s->strstart, s->match_start, s->match_length);
1562:
1563: _tr_tally_dist(s, s->strstart - s->match_start,
1564: s->match_length - MIN_MATCH, bflush);
1565:
1566: s->lookahead -= s->match_length;
1567:
1568: /* Insert new strings in the hash table only if the match length
1569: * is not too large. This saves time but degrades compression.
1570: */
1571: #ifndef FASTEST
1572: if (s->match_length <= s->max_insert_length &&
1573: s->lookahead >= MIN_MATCH) {
1574: s->match_length--; /* string at strstart already in table */
1575: do {
1576: s->strstart++;
1577: INSERT_STRING(s, s->strstart, hash_head);
1578: /* strstart never exceeds WSIZE-MAX_MATCH, so there are
1579: * always MIN_MATCH bytes ahead.
1580: */
1581: } while (--s->match_length != 0);
1582: s->strstart++;
1583: } else
1584: #endif
1585: {
1586: s->strstart += s->match_length;
1587: s->match_length = 0;
1588: s->ins_h = s->window[s->strstart];
1589: UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
1590: #if MIN_MATCH != 3
1591: Call UPDATE_HASH() MIN_MATCH-3 more times
1592: #endif
1593: /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
1594: * matter since it will be recomputed at next deflate call.
1595: */
1596: }
1597: } else {
1598: /* No match, output a literal byte */
1599: Tracevv((stderr,"%c", s->window[s->strstart]));
1600: _tr_tally_lit (s, s->window[s->strstart], bflush);
1601: s->lookahead--;
1602: s->strstart++;
1603: }
1604: if (bflush) FLUSH_BLOCK(s, 0);
1605: }
1606: FLUSH_BLOCK(s, flush == Z_FINISH);
1607: return flush == Z_FINISH ? finish_done : block_done;
1608: }
1609:
1610: #ifndef FASTEST
1611: /* ===========================================================================
1612: * Same as above, but achieves better compression. We use a lazy
1613: * evaluation for matches: a match is finally adopted only if there is
1614: * no better match at the next window position.
1615: */
1616: local block_state deflate_slow(s, flush)
1617: deflate_state *s;
1618: int flush;
1619: {
1620: IPos hash_head; /* head of hash chain */
1621: int bflush; /* set if current block must be flushed */
1622:
1623: /* Process the input block. */
1624: for (;;) {
1625: /* Make sure that we always have enough lookahead, except
1626: * at the end of the input file. We need MAX_MATCH bytes
1627: * for the next match, plus MIN_MATCH bytes to insert the
1628: * string following the next match.
1629: */
1630: if (s->lookahead < MIN_LOOKAHEAD) {
1631: fill_window(s);
1632: if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
1633: return need_more;
1634: }
1635: if (s->lookahead == 0) break; /* flush the current block */
1636: }
1637:
1638: /* Insert the string window[strstart .. strstart+2] in the
1639: * dictionary, and set hash_head to the head of the hash chain:
1640: */
1641: hash_head = NIL;
1642: if (s->lookahead >= MIN_MATCH) {
1643: INSERT_STRING(s, s->strstart, hash_head);
1644: }
1645:
1646: /* Find the longest match, discarding those <= prev_length.
1647: */
1648: s->prev_length = s->match_length, s->prev_match = s->match_start;
1649: s->match_length = MIN_MATCH-1;
1650:
1651: if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
1652: s->strstart - hash_head <= MAX_DIST(s)) {
1653: /* To simplify the code, we prevent matches with the string
1654: * of window index 0 (in particular we have to avoid a match
1655: * of the string with itself at the start of the input file).
1656: */
1657: s->match_length = longest_match (s, hash_head);
1658: /* longest_match() sets match_start */
1659:
1660: if (s->match_length <= 5 && (s->strategy == Z_FILTERED
1661: #if TOO_FAR <= 32767
1662: || (s->match_length == MIN_MATCH &&
1663: s->strstart - s->match_start > TOO_FAR)
1664: #endif
1665: )) {
1666:
1667: /* If prev_match is also MIN_MATCH, match_start is garbage
1668: * but we will ignore the current match anyway.
1669: */
1670: s->match_length = MIN_MATCH-1;
1671: }
1672: }
1673: /* If there was a match at the previous step and the current
1674: * match is not better, output the previous match:
1675: */
1676: if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
1677: uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
1678: /* Do not insert strings in hash table beyond this. */
1679:
1680: check_match(s, s->strstart-1, s->prev_match, s->prev_length);
1681:
1682: _tr_tally_dist(s, s->strstart -1 - s->prev_match,
1683: s->prev_length - MIN_MATCH, bflush);
1684:
1685: /* Insert in hash table all strings up to the end of the match.
1686: * strstart-1 and strstart are already inserted. If there is not
1687: * enough lookahead, the last two strings are not inserted in
1688: * the hash table.
1689: */
1690: s->lookahead -= s->prev_length-1;
1691: s->prev_length -= 2;
1692: do {
1693: if (++s->strstart <= max_insert) {
1694: INSERT_STRING(s, s->strstart, hash_head);
1695: }
1696: } while (--s->prev_length != 0);
1697: s->match_available = 0;
1698: s->match_length = MIN_MATCH-1;
1699: s->strstart++;
1700:
1701: if (bflush) FLUSH_BLOCK(s, 0);
1702:
1703: } else if (s->match_available) {
1704: /* If there was no match at the previous position, output a
1705: * single literal. If there was a match but the current match
1706: * is longer, truncate the previous match to a single literal.
1707: */
1708: Tracevv((stderr,"%c", s->window[s->strstart-1]));
1709: _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1710: if (bflush) {
1711: FLUSH_BLOCK_ONLY(s, 0);
1712: }
1713: s->strstart++;
1714: s->lookahead--;
1715: if (s->strm->avail_out == 0) return need_more;
1716: } else {
1717: /* There is no previous match to compare with, wait for
1718: * the next step to decide.
1719: */
1720: s->match_available = 1;
1721: s->strstart++;
1722: s->lookahead--;
1723: }
1724: }
1725: Assert (flush != Z_NO_FLUSH, "no flush?");
1726: if (s->match_available) {
1727: Tracevv((stderr,"%c", s->window[s->strstart-1]));
1728: _tr_tally_lit(s, s->window[s->strstart-1], bflush);
1729: s->match_available = 0;
1730: }
1731: FLUSH_BLOCK(s, flush == Z_FINISH);
1732: return flush == Z_FINISH ? finish_done : block_done;
1733: }
1734: #endif /* FASTEST */
1735:
1736: /* ===========================================================================
1737: * For Z_RLE, simply look for runs of bytes, generate matches only of distance
1738: * one. Do not maintain a hash table. (It will be regenerated if this run of
1739: * deflate switches away from Z_RLE.)
1740: */
1741: local block_state deflate_rle(s, flush)
1742: deflate_state *s;
1743: int flush;
1744: {
1745: int bflush; /* set if current block must be flushed */
1746: uInt prev; /* byte at distance one to match */
1747: Bytef *scan, *strend; /* scan goes up to strend for length of run */
1748:
1749: for (;;) {
1750: /* Make sure that we always have enough lookahead, except
1751: * at the end of the input file. We need MAX_MATCH bytes
1752: * for the longest encodable run.
1753: */
1754: if (s->lookahead < MAX_MATCH) {
1755: fill_window(s);
1756: if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
1757: return need_more;
1758: }
1759: if (s->lookahead == 0) break; /* flush the current block */
1760: }
1761:
1762: /* See how many times the previous byte repeats */
1763: s->match_length = 0;
1764: if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
1765: scan = s->window + s->strstart - 1;
1766: prev = *scan;
1767: if (prev == *++scan && prev == *++scan && prev == *++scan) {
1768: strend = s->window + s->strstart + MAX_MATCH;
1769: do {
1770: } while (prev == *++scan && prev == *++scan &&
1771: prev == *++scan && prev == *++scan &&
1772: prev == *++scan && prev == *++scan &&
1773: prev == *++scan && prev == *++scan &&
1774: scan < strend);
1775: s->match_length = MAX_MATCH - (int)(strend - scan);
1776: if (s->match_length > s->lookahead)
1777: s->match_length = s->lookahead;
1778: }
1779: }
1780:
1781: /* Emit match if have run of MIN_MATCH or longer, else emit literal */
1782: if (s->match_length >= MIN_MATCH) {
1783: check_match(s, s->strstart, s->strstart - 1, s->match_length);
1784:
1785: _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
1786:
1787: s->lookahead -= s->match_length;
1788: s->strstart += s->match_length;
1789: s->match_length = 0;
1790: } else {
1791: /* No match, output a literal byte */
1792: Tracevv((stderr,"%c", s->window[s->strstart]));
1793: _tr_tally_lit (s, s->window[s->strstart], bflush);
1794: s->lookahead--;
1795: s->strstart++;
1796: }
1797: if (bflush) FLUSH_BLOCK(s, 0);
1798: }
1799: FLUSH_BLOCK(s, flush == Z_FINISH);
1800: return flush == Z_FINISH ? finish_done : block_done;
1801: }
1802:
1803: /* ===========================================================================
1804: * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
1805: * (It will be regenerated if this run of deflate switches away from Huffman.)
1806: */
1807: local block_state deflate_huff(s, flush)
1808: deflate_state *s;
1809: int flush;
1810: {
1811: int bflush; /* set if current block must be flushed */
1812:
1813: for (;;) {
1814: /* Make sure that we have a literal to write. */
1815: if (s->lookahead == 0) {
1816: fill_window(s);
1817: if (s->lookahead == 0) {
1818: if (flush == Z_NO_FLUSH)
1819: return need_more;
1820: break; /* flush the current block */
1821: }
1822: }
1823:
1824: /* Output a literal byte */
1825: s->match_length = 0;
1826: Tracevv((stderr,"%c", s->window[s->strstart]));
1827: _tr_tally_lit (s, s->window[s->strstart], bflush);
1828: s->lookahead--;
1829: s->strstart++;
1830: if (bflush) FLUSH_BLOCK(s, 0);
1831: }
1832: FLUSH_BLOCK(s, flush == Z_FINISH);
1833: return flush == Z_FINISH ? finish_done : block_done;
1834: }
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