ia64/linux-2.6.18-xen.hg

view lib/zlib_inflate/inflate.c @ 740:bf8b1ee634e2

balloon: Fix the build by including <linux/init.h>

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
author Keir Fraser <keir.fraser@citrix.com>
date Tue Nov 25 11:19:41 2008 +0000 (2008-11-25)
parents 831230e53067
children
line source
1 /* inflate.c -- zlib decompression
2 * Copyright (C) 1995-2005 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
4 *
5 * Based on zlib 1.2.3 but modified for the Linux Kernel by
6 * Richard Purdie <richard@openedhand.com>
7 *
8 * Changes mainly for static instead of dynamic memory allocation
9 *
10 */
12 #include <linux/zutil.h>
13 #include "inftrees.h"
14 #include "inflate.h"
15 #include "inffast.h"
16 #include "infutil.h"
18 int zlib_inflate_workspacesize(void)
19 {
20 return sizeof(struct inflate_workspace);
21 }
23 int zlib_inflateReset(z_streamp strm)
24 {
25 struct inflate_state *state;
27 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
28 state = (struct inflate_state *)strm->state;
29 strm->total_in = strm->total_out = state->total = 0;
30 strm->msg = NULL;
31 strm->adler = 1; /* to support ill-conceived Java test suite */
32 state->mode = HEAD;
33 state->last = 0;
34 state->havedict = 0;
35 state->dmax = 32768U;
36 state->hold = 0;
37 state->bits = 0;
38 state->lencode = state->distcode = state->next = state->codes;
40 /* Initialise Window */
41 state->wsize = 1U << state->wbits;
42 state->write = 0;
43 state->whave = 0;
45 return Z_OK;
46 }
48 #if 0
49 int zlib_inflatePrime(z_streamp strm, int bits, int value)
50 {
51 struct inflate_state *state;
53 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
54 state = (struct inflate_state *)strm->state;
55 if (bits > 16 || state->bits + bits > 32) return Z_STREAM_ERROR;
56 value &= (1L << bits) - 1;
57 state->hold += value << state->bits;
58 state->bits += bits;
59 return Z_OK;
60 }
61 #endif
63 int zlib_inflateInit2(z_streamp strm, int windowBits)
64 {
65 struct inflate_state *state;
67 if (strm == NULL) return Z_STREAM_ERROR;
68 strm->msg = NULL; /* in case we return an error */
70 state = &WS(strm)->inflate_state;
71 strm->state = (struct internal_state *)state;
73 if (windowBits < 0) {
74 state->wrap = 0;
75 windowBits = -windowBits;
76 }
77 else {
78 state->wrap = (windowBits >> 4) + 1;
79 }
80 if (windowBits < 8 || windowBits > 15) {
81 return Z_STREAM_ERROR;
82 }
83 state->wbits = (unsigned)windowBits;
84 state->window = &WS(strm)->working_window[0];
86 return zlib_inflateReset(strm);
87 }
89 /*
90 Return state with length and distance decoding tables and index sizes set to
91 fixed code decoding. This returns fixed tables from inffixed.h.
92 */
93 static void zlib_fixedtables(struct inflate_state *state)
94 {
95 # include "inffixed.h"
96 state->lencode = lenfix;
97 state->lenbits = 9;
98 state->distcode = distfix;
99 state->distbits = 5;
100 }
103 /*
104 Update the window with the last wsize (normally 32K) bytes written before
105 returning. This is only called when a window is already in use, or when
106 output has been written during this inflate call, but the end of the deflate
107 stream has not been reached yet. It is also called to window dictionary data
108 when a dictionary is loaded.
110 Providing output buffers larger than 32K to inflate() should provide a speed
111 advantage, since only the last 32K of output is copied to the sliding window
112 upon return from inflate(), and since all distances after the first 32K of
113 output will fall in the output data, making match copies simpler and faster.
114 The advantage may be dependent on the size of the processor's data caches.
115 */
116 static void zlib_updatewindow(z_streamp strm, unsigned out)
117 {
118 struct inflate_state *state;
119 unsigned copy, dist;
121 state = (struct inflate_state *)strm->state;
123 /* copy state->wsize or less output bytes into the circular window */
124 copy = out - strm->avail_out;
125 if (copy >= state->wsize) {
126 memcpy(state->window, strm->next_out - state->wsize, state->wsize);
127 state->write = 0;
128 state->whave = state->wsize;
129 }
130 else {
131 dist = state->wsize - state->write;
132 if (dist > copy) dist = copy;
133 memcpy(state->window + state->write, strm->next_out - copy, dist);
134 copy -= dist;
135 if (copy) {
136 memcpy(state->window, strm->next_out - copy, copy);
137 state->write = copy;
138 state->whave = state->wsize;
139 }
140 else {
141 state->write += dist;
142 if (state->write == state->wsize) state->write = 0;
143 if (state->whave < state->wsize) state->whave += dist;
144 }
145 }
146 }
149 /*
150 * At the end of a Deflate-compressed PPP packet, we expect to have seen
151 * a `stored' block type value but not the (zero) length bytes.
152 */
153 /*
154 Returns true if inflate is currently at the end of a block generated by
155 Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
156 implementation to provide an additional safety check. PPP uses
157 Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored
158 block. When decompressing, PPP checks that at the end of input packet,
159 inflate is waiting for these length bytes.
160 */
161 static int zlib_inflateSyncPacket(z_streamp strm)
162 {
163 struct inflate_state *state;
165 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
166 state = (struct inflate_state *)strm->state;
168 if (state->mode == STORED && state->bits == 0) {
169 state->mode = TYPE;
170 return Z_OK;
171 }
172 return Z_DATA_ERROR;
173 }
175 /* Macros for inflate(): */
177 /* check function to use adler32() for zlib or crc32() for gzip */
178 #define UPDATE(check, buf, len) zlib_adler32(check, buf, len)
180 /* Load registers with state in inflate() for speed */
181 #define LOAD() \
182 do { \
183 put = strm->next_out; \
184 left = strm->avail_out; \
185 next = strm->next_in; \
186 have = strm->avail_in; \
187 hold = state->hold; \
188 bits = state->bits; \
189 } while (0)
191 /* Restore state from registers in inflate() */
192 #define RESTORE() \
193 do { \
194 strm->next_out = put; \
195 strm->avail_out = left; \
196 strm->next_in = next; \
197 strm->avail_in = have; \
198 state->hold = hold; \
199 state->bits = bits; \
200 } while (0)
202 /* Clear the input bit accumulator */
203 #define INITBITS() \
204 do { \
205 hold = 0; \
206 bits = 0; \
207 } while (0)
209 /* Get a byte of input into the bit accumulator, or return from inflate()
210 if there is no input available. */
211 #define PULLBYTE() \
212 do { \
213 if (have == 0) goto inf_leave; \
214 have--; \
215 hold += (unsigned long)(*next++) << bits; \
216 bits += 8; \
217 } while (0)
219 /* Assure that there are at least n bits in the bit accumulator. If there is
220 not enough available input to do that, then return from inflate(). */
221 #define NEEDBITS(n) \
222 do { \
223 while (bits < (unsigned)(n)) \
224 PULLBYTE(); \
225 } while (0)
227 /* Return the low n bits of the bit accumulator (n < 16) */
228 #define BITS(n) \
229 ((unsigned)hold & ((1U << (n)) - 1))
231 /* Remove n bits from the bit accumulator */
232 #define DROPBITS(n) \
233 do { \
234 hold >>= (n); \
235 bits -= (unsigned)(n); \
236 } while (0)
238 /* Remove zero to seven bits as needed to go to a byte boundary */
239 #define BYTEBITS() \
240 do { \
241 hold >>= bits & 7; \
242 bits -= bits & 7; \
243 } while (0)
245 /* Reverse the bytes in a 32-bit value */
246 #define REVERSE(q) \
247 ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \
248 (((q) & 0xff00) << 8) + (((q) & 0xff) << 24))
250 /*
251 inflate() uses a state machine to process as much input data and generate as
252 much output data as possible before returning. The state machine is
253 structured roughly as follows:
255 for (;;) switch (state) {
256 ...
257 case STATEn:
258 if (not enough input data or output space to make progress)
259 return;
260 ... make progress ...
261 state = STATEm;
262 break;
263 ...
264 }
266 so when inflate() is called again, the same case is attempted again, and
267 if the appropriate resources are provided, the machine proceeds to the
268 next state. The NEEDBITS() macro is usually the way the state evaluates
269 whether it can proceed or should return. NEEDBITS() does the return if
270 the requested bits are not available. The typical use of the BITS macros
271 is:
273 NEEDBITS(n);
274 ... do something with BITS(n) ...
275 DROPBITS(n);
277 where NEEDBITS(n) either returns from inflate() if there isn't enough
278 input left to load n bits into the accumulator, or it continues. BITS(n)
279 gives the low n bits in the accumulator. When done, DROPBITS(n) drops
280 the low n bits off the accumulator. INITBITS() clears the accumulator
281 and sets the number of available bits to zero. BYTEBITS() discards just
282 enough bits to put the accumulator on a byte boundary. After BYTEBITS()
283 and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
285 NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
286 if there is no input available. The decoding of variable length codes uses
287 PULLBYTE() directly in order to pull just enough bytes to decode the next
288 code, and no more.
290 Some states loop until they get enough input, making sure that enough
291 state information is maintained to continue the loop where it left off
292 if NEEDBITS() returns in the loop. For example, want, need, and keep
293 would all have to actually be part of the saved state in case NEEDBITS()
294 returns:
296 case STATEw:
297 while (want < need) {
298 NEEDBITS(n);
299 keep[want++] = BITS(n);
300 DROPBITS(n);
301 }
302 state = STATEx;
303 case STATEx:
305 As shown above, if the next state is also the next case, then the break
306 is omitted.
308 A state may also return if there is not enough output space available to
309 complete that state. Those states are copying stored data, writing a
310 literal byte, and copying a matching string.
312 When returning, a "goto inf_leave" is used to update the total counters,
313 update the check value, and determine whether any progress has been made
314 during that inflate() call in order to return the proper return code.
315 Progress is defined as a change in either strm->avail_in or strm->avail_out.
316 When there is a window, goto inf_leave will update the window with the last
317 output written. If a goto inf_leave occurs in the middle of decompression
318 and there is no window currently, goto inf_leave will create one and copy
319 output to the window for the next call of inflate().
321 In this implementation, the flush parameter of inflate() only affects the
322 return code (per zlib.h). inflate() always writes as much as possible to
323 strm->next_out, given the space available and the provided input--the effect
324 documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers
325 the allocation of and copying into a sliding window until necessary, which
326 provides the effect documented in zlib.h for Z_FINISH when the entire input
327 stream available. So the only thing the flush parameter actually does is:
328 when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it
329 will return Z_BUF_ERROR if it has not reached the end of the stream.
330 */
332 int zlib_inflate(z_streamp strm, int flush)
333 {
334 struct inflate_state *state;
335 unsigned char *next; /* next input */
336 unsigned char *put; /* next output */
337 unsigned have, left; /* available input and output */
338 unsigned long hold; /* bit buffer */
339 unsigned bits; /* bits in bit buffer */
340 unsigned in, out; /* save starting available input and output */
341 unsigned copy; /* number of stored or match bytes to copy */
342 unsigned char *from; /* where to copy match bytes from */
343 code this; /* current decoding table entry */
344 code last; /* parent table entry */
345 unsigned len; /* length to copy for repeats, bits to drop */
346 int ret; /* return code */
347 static const unsigned short order[19] = /* permutation of code lengths */
348 {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
350 /* Do not check for strm->next_out == NULL here as ppc zImage
351 inflates to strm->next_out = 0 */
353 if (strm == NULL || strm->state == NULL ||
354 (strm->next_in == NULL && strm->avail_in != 0))
355 return Z_STREAM_ERROR;
357 state = (struct inflate_state *)strm->state;
359 if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */
360 LOAD();
361 in = have;
362 out = left;
363 ret = Z_OK;
364 for (;;)
365 switch (state->mode) {
366 case HEAD:
367 if (state->wrap == 0) {
368 state->mode = TYPEDO;
369 break;
370 }
371 NEEDBITS(16);
372 if (
373 ((BITS(8) << 8) + (hold >> 8)) % 31) {
374 strm->msg = (char *)"incorrect header check";
375 state->mode = BAD;
376 break;
377 }
378 if (BITS(4) != Z_DEFLATED) {
379 strm->msg = (char *)"unknown compression method";
380 state->mode = BAD;
381 break;
382 }
383 DROPBITS(4);
384 len = BITS(4) + 8;
385 if (len > state->wbits) {
386 strm->msg = (char *)"invalid window size";
387 state->mode = BAD;
388 break;
389 }
390 state->dmax = 1U << len;
391 strm->adler = state->check = zlib_adler32(0L, NULL, 0);
392 state->mode = hold & 0x200 ? DICTID : TYPE;
393 INITBITS();
394 break;
395 case DICTID:
396 NEEDBITS(32);
397 strm->adler = state->check = REVERSE(hold);
398 INITBITS();
399 state->mode = DICT;
400 case DICT:
401 if (state->havedict == 0) {
402 RESTORE();
403 return Z_NEED_DICT;
404 }
405 strm->adler = state->check = zlib_adler32(0L, NULL, 0);
406 state->mode = TYPE;
407 case TYPE:
408 if (flush == Z_BLOCK) goto inf_leave;
409 case TYPEDO:
410 if (state->last) {
411 BYTEBITS();
412 state->mode = CHECK;
413 break;
414 }
415 NEEDBITS(3);
416 state->last = BITS(1);
417 DROPBITS(1);
418 switch (BITS(2)) {
419 case 0: /* stored block */
420 state->mode = STORED;
421 break;
422 case 1: /* fixed block */
423 zlib_fixedtables(state);
424 state->mode = LEN; /* decode codes */
425 break;
426 case 2: /* dynamic block */
427 state->mode = TABLE;
428 break;
429 case 3:
430 strm->msg = (char *)"invalid block type";
431 state->mode = BAD;
432 }
433 DROPBITS(2);
434 break;
435 case STORED:
436 BYTEBITS(); /* go to byte boundary */
437 NEEDBITS(32);
438 if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
439 strm->msg = (char *)"invalid stored block lengths";
440 state->mode = BAD;
441 break;
442 }
443 state->length = (unsigned)hold & 0xffff;
444 INITBITS();
445 state->mode = COPY;
446 case COPY:
447 copy = state->length;
448 if (copy) {
449 if (copy > have) copy = have;
450 if (copy > left) copy = left;
451 if (copy == 0) goto inf_leave;
452 memcpy(put, next, copy);
453 have -= copy;
454 next += copy;
455 left -= copy;
456 put += copy;
457 state->length -= copy;
458 break;
459 }
460 state->mode = TYPE;
461 break;
462 case TABLE:
463 NEEDBITS(14);
464 state->nlen = BITS(5) + 257;
465 DROPBITS(5);
466 state->ndist = BITS(5) + 1;
467 DROPBITS(5);
468 state->ncode = BITS(4) + 4;
469 DROPBITS(4);
470 #ifndef PKZIP_BUG_WORKAROUND
471 if (state->nlen > 286 || state->ndist > 30) {
472 strm->msg = (char *)"too many length or distance symbols";
473 state->mode = BAD;
474 break;
475 }
476 #endif
477 state->have = 0;
478 state->mode = LENLENS;
479 case LENLENS:
480 while (state->have < state->ncode) {
481 NEEDBITS(3);
482 state->lens[order[state->have++]] = (unsigned short)BITS(3);
483 DROPBITS(3);
484 }
485 while (state->have < 19)
486 state->lens[order[state->have++]] = 0;
487 state->next = state->codes;
488 state->lencode = (code const *)(state->next);
489 state->lenbits = 7;
490 ret = zlib_inflate_table(CODES, state->lens, 19, &(state->next),
491 &(state->lenbits), state->work);
492 if (ret) {
493 strm->msg = (char *)"invalid code lengths set";
494 state->mode = BAD;
495 break;
496 }
497 state->have = 0;
498 state->mode = CODELENS;
499 case CODELENS:
500 while (state->have < state->nlen + state->ndist) {
501 for (;;) {
502 this = state->lencode[BITS(state->lenbits)];
503 if ((unsigned)(this.bits) <= bits) break;
504 PULLBYTE();
505 }
506 if (this.val < 16) {
507 NEEDBITS(this.bits);
508 DROPBITS(this.bits);
509 state->lens[state->have++] = this.val;
510 }
511 else {
512 if (this.val == 16) {
513 NEEDBITS(this.bits + 2);
514 DROPBITS(this.bits);
515 if (state->have == 0) {
516 strm->msg = (char *)"invalid bit length repeat";
517 state->mode = BAD;
518 break;
519 }
520 len = state->lens[state->have - 1];
521 copy = 3 + BITS(2);
522 DROPBITS(2);
523 }
524 else if (this.val == 17) {
525 NEEDBITS(this.bits + 3);
526 DROPBITS(this.bits);
527 len = 0;
528 copy = 3 + BITS(3);
529 DROPBITS(3);
530 }
531 else {
532 NEEDBITS(this.bits + 7);
533 DROPBITS(this.bits);
534 len = 0;
535 copy = 11 + BITS(7);
536 DROPBITS(7);
537 }
538 if (state->have + copy > state->nlen + state->ndist) {
539 strm->msg = (char *)"invalid bit length repeat";
540 state->mode = BAD;
541 break;
542 }
543 while (copy--)
544 state->lens[state->have++] = (unsigned short)len;
545 }
546 }
548 /* handle error breaks in while */
549 if (state->mode == BAD) break;
551 /* build code tables */
552 state->next = state->codes;
553 state->lencode = (code const *)(state->next);
554 state->lenbits = 9;
555 ret = zlib_inflate_table(LENS, state->lens, state->nlen, &(state->next),
556 &(state->lenbits), state->work);
557 if (ret) {
558 strm->msg = (char *)"invalid literal/lengths set";
559 state->mode = BAD;
560 break;
561 }
562 state->distcode = (code const *)(state->next);
563 state->distbits = 6;
564 ret = zlib_inflate_table(DISTS, state->lens + state->nlen, state->ndist,
565 &(state->next), &(state->distbits), state->work);
566 if (ret) {
567 strm->msg = (char *)"invalid distances set";
568 state->mode = BAD;
569 break;
570 }
571 state->mode = LEN;
572 case LEN:
573 if (have >= 6 && left >= 258) {
574 RESTORE();
575 inflate_fast(strm, out);
576 LOAD();
577 break;
578 }
579 for (;;) {
580 this = state->lencode[BITS(state->lenbits)];
581 if ((unsigned)(this.bits) <= bits) break;
582 PULLBYTE();
583 }
584 if (this.op && (this.op & 0xf0) == 0) {
585 last = this;
586 for (;;) {
587 this = state->lencode[last.val +
588 (BITS(last.bits + last.op) >> last.bits)];
589 if ((unsigned)(last.bits + this.bits) <= bits) break;
590 PULLBYTE();
591 }
592 DROPBITS(last.bits);
593 }
594 DROPBITS(this.bits);
595 state->length = (unsigned)this.val;
596 if ((int)(this.op) == 0) {
597 state->mode = LIT;
598 break;
599 }
600 if (this.op & 32) {
601 state->mode = TYPE;
602 break;
603 }
604 if (this.op & 64) {
605 strm->msg = (char *)"invalid literal/length code";
606 state->mode = BAD;
607 break;
608 }
609 state->extra = (unsigned)(this.op) & 15;
610 state->mode = LENEXT;
611 case LENEXT:
612 if (state->extra) {
613 NEEDBITS(state->extra);
614 state->length += BITS(state->extra);
615 DROPBITS(state->extra);
616 }
617 state->mode = DIST;
618 case DIST:
619 for (;;) {
620 this = state->distcode[BITS(state->distbits)];
621 if ((unsigned)(this.bits) <= bits) break;
622 PULLBYTE();
623 }
624 if ((this.op & 0xf0) == 0) {
625 last = this;
626 for (;;) {
627 this = state->distcode[last.val +
628 (BITS(last.bits + last.op) >> last.bits)];
629 if ((unsigned)(last.bits + this.bits) <= bits) break;
630 PULLBYTE();
631 }
632 DROPBITS(last.bits);
633 }
634 DROPBITS(this.bits);
635 if (this.op & 64) {
636 strm->msg = (char *)"invalid distance code";
637 state->mode = BAD;
638 break;
639 }
640 state->offset = (unsigned)this.val;
641 state->extra = (unsigned)(this.op) & 15;
642 state->mode = DISTEXT;
643 case DISTEXT:
644 if (state->extra) {
645 NEEDBITS(state->extra);
646 state->offset += BITS(state->extra);
647 DROPBITS(state->extra);
648 }
649 #ifdef INFLATE_STRICT
650 if (state->offset > state->dmax) {
651 strm->msg = (char *)"invalid distance too far back";
652 state->mode = BAD;
653 break;
654 }
655 #endif
656 if (state->offset > state->whave + out - left) {
657 strm->msg = (char *)"invalid distance too far back";
658 state->mode = BAD;
659 break;
660 }
661 state->mode = MATCH;
662 case MATCH:
663 if (left == 0) goto inf_leave;
664 copy = out - left;
665 if (state->offset > copy) { /* copy from window */
666 copy = state->offset - copy;
667 if (copy > state->write) {
668 copy -= state->write;
669 from = state->window + (state->wsize - copy);
670 }
671 else
672 from = state->window + (state->write - copy);
673 if (copy > state->length) copy = state->length;
674 }
675 else { /* copy from output */
676 from = put - state->offset;
677 copy = state->length;
678 }
679 if (copy > left) copy = left;
680 left -= copy;
681 state->length -= copy;
682 do {
683 *put++ = *from++;
684 } while (--copy);
685 if (state->length == 0) state->mode = LEN;
686 break;
687 case LIT:
688 if (left == 0) goto inf_leave;
689 *put++ = (unsigned char)(state->length);
690 left--;
691 state->mode = LEN;
692 break;
693 case CHECK:
694 if (state->wrap) {
695 NEEDBITS(32);
696 out -= left;
697 strm->total_out += out;
698 state->total += out;
699 if (out)
700 strm->adler = state->check =
701 UPDATE(state->check, put - out, out);
702 out = left;
703 if ((
704 REVERSE(hold)) != state->check) {
705 strm->msg = (char *)"incorrect data check";
706 state->mode = BAD;
707 break;
708 }
709 INITBITS();
710 }
711 state->mode = DONE;
712 case DONE:
713 ret = Z_STREAM_END;
714 goto inf_leave;
715 case BAD:
716 ret = Z_DATA_ERROR;
717 goto inf_leave;
718 case MEM:
719 return Z_MEM_ERROR;
720 case SYNC:
721 default:
722 return Z_STREAM_ERROR;
723 }
725 /*
726 Return from inflate(), updating the total counts and the check value.
727 If there was no progress during the inflate() call, return a buffer
728 error. Call zlib_updatewindow() to create and/or update the window state.
729 */
730 inf_leave:
731 RESTORE();
732 if (state->wsize || (state->mode < CHECK && out != strm->avail_out))
733 zlib_updatewindow(strm, out);
735 in -= strm->avail_in;
736 out -= strm->avail_out;
737 strm->total_in += in;
738 strm->total_out += out;
739 state->total += out;
740 if (state->wrap && out)
741 strm->adler = state->check =
742 UPDATE(state->check, strm->next_out - out, out);
744 strm->data_type = state->bits + (state->last ? 64 : 0) +
745 (state->mode == TYPE ? 128 : 0);
746 if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
747 ret = Z_BUF_ERROR;
749 if (flush == Z_PACKET_FLUSH && ret == Z_OK &&
750 (strm->avail_out != 0 || strm->avail_in == 0))
751 return zlib_inflateSyncPacket(strm);
752 return ret;
753 }
755 int zlib_inflateEnd(z_streamp strm)
756 {
757 if (strm == NULL || strm->state == NULL)
758 return Z_STREAM_ERROR;
759 return Z_OK;
760 }
762 #if 0
763 int zlib_inflateSetDictionary(z_streamp strm, const Byte *dictionary,
764 uInt dictLength)
765 {
766 struct inflate_state *state;
767 unsigned long id;
769 /* check state */
770 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
771 state = (struct inflate_state *)strm->state;
772 if (state->wrap != 0 && state->mode != DICT)
773 return Z_STREAM_ERROR;
775 /* check for correct dictionary id */
776 if (state->mode == DICT) {
777 id = zlib_adler32(0L, NULL, 0);
778 id = zlib_adler32(id, dictionary, dictLength);
779 if (id != state->check)
780 return Z_DATA_ERROR;
781 }
783 /* copy dictionary to window */
784 zlib_updatewindow(strm, strm->avail_out);
786 if (dictLength > state->wsize) {
787 memcpy(state->window, dictionary + dictLength - state->wsize,
788 state->wsize);
789 state->whave = state->wsize;
790 }
791 else {
792 memcpy(state->window + state->wsize - dictLength, dictionary,
793 dictLength);
794 state->whave = dictLength;
795 }
796 state->havedict = 1;
797 return Z_OK;
798 }
799 #endif
801 #if 0
802 /*
803 Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff. Return when found
804 or when out of input. When called, *have is the number of pattern bytes
805 found in order so far, in 0..3. On return *have is updated to the new
806 state. If on return *have equals four, then the pattern was found and the
807 return value is how many bytes were read including the last byte of the
808 pattern. If *have is less than four, then the pattern has not been found
809 yet and the return value is len. In the latter case, zlib_syncsearch() can be
810 called again with more data and the *have state. *have is initialized to
811 zero for the first call.
812 */
813 static unsigned zlib_syncsearch(unsigned *have, unsigned char *buf,
814 unsigned len)
815 {
816 unsigned got;
817 unsigned next;
819 got = *have;
820 next = 0;
821 while (next < len && got < 4) {
822 if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
823 got++;
824 else if (buf[next])
825 got = 0;
826 else
827 got = 4 - got;
828 next++;
829 }
830 *have = got;
831 return next;
832 }
833 #endif
835 #if 0
836 int zlib_inflateSync(z_streamp strm)
837 {
838 unsigned len; /* number of bytes to look at or looked at */
839 unsigned long in, out; /* temporary to save total_in and total_out */
840 unsigned char buf[4]; /* to restore bit buffer to byte string */
841 struct inflate_state *state;
843 /* check parameters */
844 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
845 state = (struct inflate_state *)strm->state;
846 if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;
848 /* if first time, start search in bit buffer */
849 if (state->mode != SYNC) {
850 state->mode = SYNC;
851 state->hold <<= state->bits & 7;
852 state->bits -= state->bits & 7;
853 len = 0;
854 while (state->bits >= 8) {
855 buf[len++] = (unsigned char)(state->hold);
856 state->hold >>= 8;
857 state->bits -= 8;
858 }
859 state->have = 0;
860 zlib_syncsearch(&(state->have), buf, len);
861 }
863 /* search available input */
864 len = zlib_syncsearch(&(state->have), strm->next_in, strm->avail_in);
865 strm->avail_in -= len;
866 strm->next_in += len;
867 strm->total_in += len;
869 /* return no joy or set up to restart inflate() on a new block */
870 if (state->have != 4) return Z_DATA_ERROR;
871 in = strm->total_in; out = strm->total_out;
872 zlib_inflateReset(strm);
873 strm->total_in = in; strm->total_out = out;
874 state->mode = TYPE;
875 return Z_OK;
876 }
877 #endif
879 /*
880 * This subroutine adds the data at next_in/avail_in to the output history
881 * without performing any output. The output buffer must be "caught up";
882 * i.e. no pending output but this should always be the case. The state must
883 * be waiting on the start of a block (i.e. mode == TYPE or HEAD). On exit,
884 * the output will also be caught up, and the checksum will have been updated
885 * if need be.
886 */
887 int zlib_inflateIncomp(z_stream *z)
888 {
889 struct inflate_state *state = (struct inflate_state *)z->state;
890 Byte *saved_no = z->next_out;
891 uInt saved_ao = z->avail_out;
893 if (state->mode != TYPE && state->mode != HEAD)
894 return Z_DATA_ERROR;
896 /* Setup some variables to allow misuse of updateWindow */
897 z->avail_out = 0;
898 z->next_out = z->next_in + z->avail_in;
900 zlib_updatewindow(z, z->avail_in);
902 /* Restore saved variables */
903 z->avail_out = saved_ao;
904 z->next_out = saved_no;
906 z->adler = state->check =
907 UPDATE(state->check, z->next_in, z->avail_in);
909 z->total_out += z->avail_in;
910 z->total_in += z->avail_in;
911 z->next_in += z->avail_in;
912 state->total += z->avail_in;
913 z->avail_in = 0;
915 return Z_OK;
916 }