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 */
11
12 #include <linux/zutil.h>
13 #include "inftrees.h"
14 #include "inflate.h"
15 #include "inffast.h"
16 #include "infutil.h"
17
18 /* architecture-specific bits */
19 #ifdef CONFIG_ZLIB_DFLTCC
20 # include "../zlib_dfltcc/dfltcc.h"
21 #else
22 #define INFLATE_RESET_HOOK(strm) do {} while (0)
23 #define INFLATE_TYPEDO_HOOK(strm, flush) do {} while (0)
24 #define INFLATE_NEED_UPDATEWINDOW(strm) 1
25 #define INFLATE_NEED_CHECKSUM(strm) 1
26 #endif
27
zlib_inflate_workspacesize(void)28 int zlib_inflate_workspacesize(void)
29 {
30 return sizeof(struct inflate_workspace);
31 }
32
zlib_inflateReset(z_streamp strm)33 int zlib_inflateReset(z_streamp strm)
34 {
35 struct inflate_state *state;
36
37 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
38 state = (struct inflate_state *)strm->state;
39 strm->total_in = strm->total_out = state->total = 0;
40 strm->msg = NULL;
41 strm->adler = 1; /* to support ill-conceived Java test suite */
42 state->mode = HEAD;
43 state->last = 0;
44 state->havedict = 0;
45 state->dmax = 32768U;
46 state->hold = 0;
47 state->bits = 0;
48 state->lencode = state->distcode = state->next = state->codes;
49
50 /* Initialise Window */
51 state->wsize = 1U << state->wbits;
52 state->write = 0;
53 state->whave = 0;
54
55 INFLATE_RESET_HOOK(strm);
56 return Z_OK;
57 }
58
zlib_inflateInit2(z_streamp strm,int windowBits)59 int zlib_inflateInit2(z_streamp strm, int windowBits)
60 {
61 struct inflate_state *state;
62
63 if (strm == NULL) return Z_STREAM_ERROR;
64 strm->msg = NULL; /* in case we return an error */
65
66 state = &WS(strm)->inflate_state;
67 strm->state = (struct internal_state *)state;
68
69 if (windowBits < 0) {
70 state->wrap = 0;
71 windowBits = -windowBits;
72 }
73 else {
74 state->wrap = (windowBits >> 4) + 1;
75 }
76 if (windowBits < 8 || windowBits > 15) {
77 return Z_STREAM_ERROR;
78 }
79 state->wbits = (unsigned)windowBits;
80 #ifdef CONFIG_ZLIB_DFLTCC
81 /*
82 * DFLTCC requires the window to be page aligned.
83 * Thus, we overallocate and take the aligned portion of the buffer.
84 */
85 state->window = PTR_ALIGN(&WS(strm)->working_window[0], PAGE_SIZE);
86 #else
87 state->window = &WS(strm)->working_window[0];
88 #endif
89
90 return zlib_inflateReset(strm);
91 }
92
93 /*
94 Return state with length and distance decoding tables and index sizes set to
95 fixed code decoding. This returns fixed tables from inffixed.h.
96 */
zlib_fixedtables(struct inflate_state * state)97 static void zlib_fixedtables(struct inflate_state *state)
98 {
99 # include "inffixed.h"
100 state->lencode = lenfix;
101 state->lenbits = 9;
102 state->distcode = distfix;
103 state->distbits = 5;
104 }
105
106
107 /*
108 Update the window with the last wsize (normally 32K) bytes written before
109 returning. This is only called when a window is already in use, or when
110 output has been written during this inflate call, but the end of the deflate
111 stream has not been reached yet. It is also called to window dictionary data
112 when a dictionary is loaded.
113
114 Providing output buffers larger than 32K to inflate() should provide a speed
115 advantage, since only the last 32K of output is copied to the sliding window
116 upon return from inflate(), and since all distances after the first 32K of
117 output will fall in the output data, making match copies simpler and faster.
118 The advantage may be dependent on the size of the processor's data caches.
119 */
zlib_updatewindow(z_streamp strm,unsigned out)120 static void zlib_updatewindow(z_streamp strm, unsigned out)
121 {
122 struct inflate_state *state;
123 unsigned copy, dist;
124
125 state = (struct inflate_state *)strm->state;
126
127 /* copy state->wsize or less output bytes into the circular window */
128 copy = out - strm->avail_out;
129 if (copy >= state->wsize) {
130 memcpy(state->window, strm->next_out - state->wsize, state->wsize);
131 state->write = 0;
132 state->whave = state->wsize;
133 }
134 else {
135 dist = state->wsize - state->write;
136 if (dist > copy) dist = copy;
137 memcpy(state->window + state->write, strm->next_out - copy, dist);
138 copy -= dist;
139 if (copy) {
140 memcpy(state->window, strm->next_out - copy, copy);
141 state->write = copy;
142 state->whave = state->wsize;
143 }
144 else {
145 state->write += dist;
146 if (state->write == state->wsize) state->write = 0;
147 if (state->whave < state->wsize) state->whave += dist;
148 }
149 }
150 }
151
152
153 /*
154 * At the end of a Deflate-compressed PPP packet, we expect to have seen
155 * a `stored' block type value but not the (zero) length bytes.
156 */
157 /*
158 Returns true if inflate is currently at the end of a block generated by
159 Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
160 implementation to provide an additional safety check. PPP uses
161 Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored
162 block. When decompressing, PPP checks that at the end of input packet,
163 inflate is waiting for these length bytes.
164 */
zlib_inflateSyncPacket(z_streamp strm)165 static int zlib_inflateSyncPacket(z_streamp strm)
166 {
167 struct inflate_state *state;
168
169 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
170 state = (struct inflate_state *)strm->state;
171
172 if (state->mode == STORED && state->bits == 0) {
173 state->mode = TYPE;
174 return Z_OK;
175 }
176 return Z_DATA_ERROR;
177 }
178
179 /* Macros for inflate(): */
180
181 /* check function to use adler32() for zlib or crc32() for gzip */
182 #define UPDATE(check, buf, len) zlib_adler32(check, buf, len)
183
184 /* Load registers with state in inflate() for speed */
185 #define LOAD() \
186 do { \
187 put = strm->next_out; \
188 left = strm->avail_out; \
189 next = strm->next_in; \
190 have = strm->avail_in; \
191 hold = state->hold; \
192 bits = state->bits; \
193 } while (0)
194
195 /* Restore state from registers in inflate() */
196 #define RESTORE() \
197 do { \
198 strm->next_out = put; \
199 strm->avail_out = left; \
200 strm->next_in = next; \
201 strm->avail_in = have; \
202 state->hold = hold; \
203 state->bits = bits; \
204 } while (0)
205
206 /* Clear the input bit accumulator */
207 #define INITBITS() \
208 do { \
209 hold = 0; \
210 bits = 0; \
211 } while (0)
212
213 /* Get a byte of input into the bit accumulator, or return from inflate()
214 if there is no input available. */
215 #define PULLBYTE() \
216 do { \
217 if (have == 0) goto inf_leave; \
218 have--; \
219 hold += (unsigned long)(*next++) << bits; \
220 bits += 8; \
221 } while (0)
222
223 /* Assure that there are at least n bits in the bit accumulator. If there is
224 not enough available input to do that, then return from inflate(). */
225 #define NEEDBITS(n) \
226 do { \
227 while (bits < (unsigned)(n)) \
228 PULLBYTE(); \
229 } while (0)
230
231 /* Return the low n bits of the bit accumulator (n < 16) */
232 #define BITS(n) \
233 ((unsigned)hold & ((1U << (n)) - 1))
234
235 /* Remove n bits from the bit accumulator */
236 #define DROPBITS(n) \
237 do { \
238 hold >>= (n); \
239 bits -= (unsigned)(n); \
240 } while (0)
241
242 /* Remove zero to seven bits as needed to go to a byte boundary */
243 #define BYTEBITS() \
244 do { \
245 hold >>= bits & 7; \
246 bits -= bits & 7; \
247 } while (0)
248
249 /*
250 inflate() uses a state machine to process as much input data and generate as
251 much output data as possible before returning. The state machine is
252 structured roughly as follows:
253
254 for (;;) switch (state) {
255 ...
256 case STATEn:
257 if (not enough input data or output space to make progress)
258 return;
259 ... make progress ...
260 state = STATEm;
261 break;
262 ...
263 }
264
265 so when inflate() is called again, the same case is attempted again, and
266 if the appropriate resources are provided, the machine proceeds to the
267 next state. The NEEDBITS() macro is usually the way the state evaluates
268 whether it can proceed or should return. NEEDBITS() does the return if
269 the requested bits are not available. The typical use of the BITS macros
270 is:
271
272 NEEDBITS(n);
273 ... do something with BITS(n) ...
274 DROPBITS(n);
275
276 where NEEDBITS(n) either returns from inflate() if there isn't enough
277 input left to load n bits into the accumulator, or it continues. BITS(n)
278 gives the low n bits in the accumulator. When done, DROPBITS(n) drops
279 the low n bits off the accumulator. INITBITS() clears the accumulator
280 and sets the number of available bits to zero. BYTEBITS() discards just
281 enough bits to put the accumulator on a byte boundary. After BYTEBITS()
282 and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
283
284 NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
285 if there is no input available. The decoding of variable length codes uses
286 PULLBYTE() directly in order to pull just enough bytes to decode the next
287 code, and no more.
288
289 Some states loop until they get enough input, making sure that enough
290 state information is maintained to continue the loop where it left off
291 if NEEDBITS() returns in the loop. For example, want, need, and keep
292 would all have to actually be part of the saved state in case NEEDBITS()
293 returns:
294
295 case STATEw:
296 while (want < need) {
297 NEEDBITS(n);
298 keep[want++] = BITS(n);
299 DROPBITS(n);
300 }
301 state = STATEx;
302 case STATEx:
303
304 As shown above, if the next state is also the next case, then the break
305 is omitted.
306
307 A state may also return if there is not enough output space available to
308 complete that state. Those states are copying stored data, writing a
309 literal byte, and copying a matching string.
310
311 When returning, a "goto inf_leave" is used to update the total counters,
312 update the check value, and determine whether any progress has been made
313 during that inflate() call in order to return the proper return code.
314 Progress is defined as a change in either strm->avail_in or strm->avail_out.
315 When there is a window, goto inf_leave will update the window with the last
316 output written. If a goto inf_leave occurs in the middle of decompression
317 and there is no window currently, goto inf_leave will create one and copy
318 output to the window for the next call of inflate().
319
320 In this implementation, the flush parameter of inflate() only affects the
321 return code (per zlib.h). inflate() always writes as much as possible to
322 strm->next_out, given the space available and the provided input--the effect
323 documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers
324 the allocation of and copying into a sliding window until necessary, which
325 provides the effect documented in zlib.h for Z_FINISH when the entire input
326 stream available. So the only thing the flush parameter actually does is:
327 when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it
328 will return Z_BUF_ERROR if it has not reached the end of the stream.
329 */
330
zlib_inflate(z_streamp strm,int flush)331 int zlib_inflate(z_streamp strm, int flush)
332 {
333 struct inflate_state *state;
334 const unsigned char *next; /* next input */
335 unsigned char *put; /* next output */
336 unsigned have, left; /* available input and output */
337 unsigned long hold; /* bit buffer */
338 unsigned bits; /* bits in bit buffer */
339 unsigned in, out; /* save starting available input and output */
340 unsigned copy; /* number of stored or match bytes to copy */
341 unsigned char *from; /* where to copy match bytes from */
342 code this; /* current decoding table entry */
343 code last; /* parent table entry */
344 unsigned len; /* length to copy for repeats, bits to drop */
345 int ret; /* return code */
346 static const unsigned short order[19] = /* permutation of code lengths */
347 {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
348
349 /* Do not check for strm->next_out == NULL here as ppc zImage
350 inflates to strm->next_out = 0 */
351
352 if (strm == NULL || strm->state == NULL ||
353 (strm->next_in == NULL && strm->avail_in != 0))
354 return Z_STREAM_ERROR;
355
356 state = (struct inflate_state *)strm->state;
357
358 if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */
359 LOAD();
360 in = have;
361 out = left;
362 ret = Z_OK;
363 for (;;)
364 switch (state->mode) {
365 case HEAD:
366 if (state->wrap == 0) {
367 state->mode = TYPEDO;
368 break;
369 }
370 NEEDBITS(16);
371 if (
372 ((BITS(8) << 8) + (hold >> 8)) % 31) {
373 strm->msg = (char *)"incorrect header check";
374 state->mode = BAD;
375 break;
376 }
377 if (BITS(4) != Z_DEFLATED) {
378 strm->msg = (char *)"unknown compression method";
379 state->mode = BAD;
380 break;
381 }
382 DROPBITS(4);
383 len = BITS(4) + 8;
384 if (len > state->wbits) {
385 strm->msg = (char *)"invalid window size";
386 state->mode = BAD;
387 break;
388 }
389 state->dmax = 1U << len;
390 strm->adler = state->check = zlib_adler32(0L, NULL, 0);
391 state->mode = hold & 0x200 ? DICTID : TYPE;
392 INITBITS();
393 break;
394 case DICTID:
395 NEEDBITS(32);
396 strm->adler = state->check = REVERSE(hold);
397 INITBITS();
398 state->mode = DICT;
399 fallthrough;
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 fallthrough;
408 case TYPE:
409 if (flush == Z_BLOCK) goto inf_leave;
410 fallthrough;
411 case TYPEDO:
412 INFLATE_TYPEDO_HOOK(strm, flush);
413 if (state->last) {
414 BYTEBITS();
415 state->mode = CHECK;
416 break;
417 }
418 NEEDBITS(3);
419 state->last = BITS(1);
420 DROPBITS(1);
421 switch (BITS(2)) {
422 case 0: /* stored block */
423 state->mode = STORED;
424 break;
425 case 1: /* fixed block */
426 zlib_fixedtables(state);
427 state->mode = LEN; /* decode codes */
428 break;
429 case 2: /* dynamic block */
430 state->mode = TABLE;
431 break;
432 case 3:
433 strm->msg = (char *)"invalid block type";
434 state->mode = BAD;
435 }
436 DROPBITS(2);
437 break;
438 case STORED:
439 BYTEBITS(); /* go to byte boundary */
440 NEEDBITS(32);
441 if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
442 strm->msg = (char *)"invalid stored block lengths";
443 state->mode = BAD;
444 break;
445 }
446 state->length = (unsigned)hold & 0xffff;
447 INITBITS();
448 state->mode = COPY;
449 fallthrough;
450 case COPY:
451 copy = state->length;
452 if (copy) {
453 if (copy > have) copy = have;
454 if (copy > left) copy = left;
455 if (copy == 0) goto inf_leave;
456 memcpy(put, next, copy);
457 have -= copy;
458 next += copy;
459 left -= copy;
460 put += copy;
461 state->length -= copy;
462 break;
463 }
464 state->mode = TYPE;
465 break;
466 case TABLE:
467 NEEDBITS(14);
468 state->nlen = BITS(5) + 257;
469 DROPBITS(5);
470 state->ndist = BITS(5) + 1;
471 DROPBITS(5);
472 state->ncode = BITS(4) + 4;
473 DROPBITS(4);
474 #ifndef PKZIP_BUG_WORKAROUND
475 if (state->nlen > 286 || state->ndist > 30) {
476 strm->msg = (char *)"too many length or distance symbols";
477 state->mode = BAD;
478 break;
479 }
480 #endif
481 state->have = 0;
482 state->mode = LENLENS;
483 fallthrough;
484 case LENLENS:
485 while (state->have < state->ncode) {
486 NEEDBITS(3);
487 state->lens[order[state->have++]] = (unsigned short)BITS(3);
488 DROPBITS(3);
489 }
490 while (state->have < 19)
491 state->lens[order[state->have++]] = 0;
492 state->next = state->codes;
493 state->lencode = (code const *)(state->next);
494 state->lenbits = 7;
495 ret = zlib_inflate_table(CODES, state->lens, 19, &(state->next),
496 &(state->lenbits), state->work);
497 if (ret) {
498 strm->msg = (char *)"invalid code lengths set";
499 state->mode = BAD;
500 break;
501 }
502 state->have = 0;
503 state->mode = CODELENS;
504 fallthrough;
505 case CODELENS:
506 while (state->have < state->nlen + state->ndist) {
507 for (;;) {
508 this = state->lencode[BITS(state->lenbits)];
509 if ((unsigned)(this.bits) <= bits) break;
510 PULLBYTE();
511 }
512 if (this.val < 16) {
513 NEEDBITS(this.bits);
514 DROPBITS(this.bits);
515 state->lens[state->have++] = this.val;
516 }
517 else {
518 if (this.val == 16) {
519 NEEDBITS(this.bits + 2);
520 DROPBITS(this.bits);
521 if (state->have == 0) {
522 strm->msg = (char *)"invalid bit length repeat";
523 state->mode = BAD;
524 break;
525 }
526 len = state->lens[state->have - 1];
527 copy = 3 + BITS(2);
528 DROPBITS(2);
529 }
530 else if (this.val == 17) {
531 NEEDBITS(this.bits + 3);
532 DROPBITS(this.bits);
533 len = 0;
534 copy = 3 + BITS(3);
535 DROPBITS(3);
536 }
537 else {
538 NEEDBITS(this.bits + 7);
539 DROPBITS(this.bits);
540 len = 0;
541 copy = 11 + BITS(7);
542 DROPBITS(7);
543 }
544 if (state->have + copy > state->nlen + state->ndist) {
545 strm->msg = (char *)"invalid bit length repeat";
546 state->mode = BAD;
547 break;
548 }
549 while (copy--)
550 state->lens[state->have++] = (unsigned short)len;
551 }
552 }
553
554 /* handle error breaks in while */
555 if (state->mode == BAD) break;
556
557 /* build code tables */
558 state->next = state->codes;
559 state->lencode = (code const *)(state->next);
560 state->lenbits = 9;
561 ret = zlib_inflate_table(LENS, state->lens, state->nlen, &(state->next),
562 &(state->lenbits), state->work);
563 if (ret) {
564 strm->msg = (char *)"invalid literal/lengths set";
565 state->mode = BAD;
566 break;
567 }
568 state->distcode = (code const *)(state->next);
569 state->distbits = 6;
570 ret = zlib_inflate_table(DISTS, state->lens + state->nlen, state->ndist,
571 &(state->next), &(state->distbits), state->work);
572 if (ret) {
573 strm->msg = (char *)"invalid distances set";
574 state->mode = BAD;
575 break;
576 }
577 state->mode = LEN;
578 fallthrough;
579 case LEN:
580 if (have >= 6 && left >= 258) {
581 RESTORE();
582 inflate_fast(strm, out);
583 LOAD();
584 break;
585 }
586 for (;;) {
587 this = state->lencode[BITS(state->lenbits)];
588 if ((unsigned)(this.bits) <= bits) break;
589 PULLBYTE();
590 }
591 if (this.op && (this.op & 0xf0) == 0) {
592 last = this;
593 for (;;) {
594 this = state->lencode[last.val +
595 (BITS(last.bits + last.op) >> last.bits)];
596 if ((unsigned)(last.bits + this.bits) <= bits) break;
597 PULLBYTE();
598 }
599 DROPBITS(last.bits);
600 }
601 DROPBITS(this.bits);
602 state->length = (unsigned)this.val;
603 if ((int)(this.op) == 0) {
604 state->mode = LIT;
605 break;
606 }
607 if (this.op & 32) {
608 state->mode = TYPE;
609 break;
610 }
611 if (this.op & 64) {
612 strm->msg = (char *)"invalid literal/length code";
613 state->mode = BAD;
614 break;
615 }
616 state->extra = (unsigned)(this.op) & 15;
617 state->mode = LENEXT;
618 fallthrough;
619 case LENEXT:
620 if (state->extra) {
621 NEEDBITS(state->extra);
622 state->length += BITS(state->extra);
623 DROPBITS(state->extra);
624 }
625 state->mode = DIST;
626 fallthrough;
627 case DIST:
628 for (;;) {
629 this = state->distcode[BITS(state->distbits)];
630 if ((unsigned)(this.bits) <= bits) break;
631 PULLBYTE();
632 }
633 if ((this.op & 0xf0) == 0) {
634 last = this;
635 for (;;) {
636 this = state->distcode[last.val +
637 (BITS(last.bits + last.op) >> last.bits)];
638 if ((unsigned)(last.bits + this.bits) <= bits) break;
639 PULLBYTE();
640 }
641 DROPBITS(last.bits);
642 }
643 DROPBITS(this.bits);
644 if (this.op & 64) {
645 strm->msg = (char *)"invalid distance code";
646 state->mode = BAD;
647 break;
648 }
649 state->offset = (unsigned)this.val;
650 state->extra = (unsigned)(this.op) & 15;
651 state->mode = DISTEXT;
652 fallthrough;
653 case DISTEXT:
654 if (state->extra) {
655 NEEDBITS(state->extra);
656 state->offset += BITS(state->extra);
657 DROPBITS(state->extra);
658 }
659 #ifdef INFLATE_STRICT
660 if (state->offset > state->dmax) {
661 strm->msg = (char *)"invalid distance too far back";
662 state->mode = BAD;
663 break;
664 }
665 #endif
666 if (state->offset > state->whave + out - left) {
667 strm->msg = (char *)"invalid distance too far back";
668 state->mode = BAD;
669 break;
670 }
671 state->mode = MATCH;
672 fallthrough;
673 case MATCH:
674 if (left == 0) goto inf_leave;
675 copy = out - left;
676 if (state->offset > copy) { /* copy from window */
677 copy = state->offset - copy;
678 if (copy > state->write) {
679 copy -= state->write;
680 from = state->window + (state->wsize - copy);
681 }
682 else
683 from = state->window + (state->write - copy);
684 if (copy > state->length) copy = state->length;
685 }
686 else { /* copy from output */
687 from = put - state->offset;
688 copy = state->length;
689 }
690 if (copy > left) copy = left;
691 left -= copy;
692 state->length -= copy;
693 do {
694 *put++ = *from++;
695 } while (--copy);
696 if (state->length == 0) state->mode = LEN;
697 break;
698 case LIT:
699 if (left == 0) goto inf_leave;
700 *put++ = (unsigned char)(state->length);
701 left--;
702 state->mode = LEN;
703 break;
704 case CHECK:
705 if (state->wrap) {
706 NEEDBITS(32);
707 out -= left;
708 strm->total_out += out;
709 state->total += out;
710 if (INFLATE_NEED_CHECKSUM(strm) && out)
711 strm->adler = state->check =
712 UPDATE(state->check, put - out, out);
713 out = left;
714 if ((
715 REVERSE(hold)) != state->check) {
716 strm->msg = (char *)"incorrect data check";
717 state->mode = BAD;
718 break;
719 }
720 INITBITS();
721 }
722 state->mode = DONE;
723 fallthrough;
724 case DONE:
725 ret = Z_STREAM_END;
726 goto inf_leave;
727 case BAD:
728 ret = Z_DATA_ERROR;
729 goto inf_leave;
730 case MEM:
731 return Z_MEM_ERROR;
732 case SYNC:
733 default:
734 return Z_STREAM_ERROR;
735 }
736
737 /*
738 Return from inflate(), updating the total counts and the check value.
739 If there was no progress during the inflate() call, return a buffer
740 error. Call zlib_updatewindow() to create and/or update the window state.
741 */
742 inf_leave:
743 RESTORE();
744 if (INFLATE_NEED_UPDATEWINDOW(strm) &&
745 (state->wsize || (state->mode < CHECK && out != strm->avail_out)))
746 zlib_updatewindow(strm, out);
747
748 in -= strm->avail_in;
749 out -= strm->avail_out;
750 strm->total_in += in;
751 strm->total_out += out;
752 state->total += out;
753 if (INFLATE_NEED_CHECKSUM(strm) && state->wrap && out)
754 strm->adler = state->check =
755 UPDATE(state->check, strm->next_out - out, out);
756
757 strm->data_type = state->bits + (state->last ? 64 : 0) +
758 (state->mode == TYPE ? 128 : 0);
759
760 if (flush == Z_PACKET_FLUSH && ret == Z_OK &&
761 strm->avail_out != 0 && strm->avail_in == 0)
762 return zlib_inflateSyncPacket(strm);
763
764 if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
765 ret = Z_BUF_ERROR;
766
767 return ret;
768 }
769
zlib_inflateEnd(z_streamp strm)770 int zlib_inflateEnd(z_streamp strm)
771 {
772 if (strm == NULL || strm->state == NULL)
773 return Z_STREAM_ERROR;
774 return Z_OK;
775 }
776
777 /*
778 * This subroutine adds the data at next_in/avail_in to the output history
779 * without performing any output. The output buffer must be "caught up";
780 * i.e. no pending output but this should always be the case. The state must
781 * be waiting on the start of a block (i.e. mode == TYPE or HEAD). On exit,
782 * the output will also be caught up, and the checksum will have been updated
783 * if need be.
784 */
zlib_inflateIncomp(z_stream * z)785 int zlib_inflateIncomp(z_stream *z)
786 {
787 struct inflate_state *state = (struct inflate_state *)z->state;
788 Byte *saved_no = z->next_out;
789 uInt saved_ao = z->avail_out;
790
791 if (state->mode != TYPE && state->mode != HEAD)
792 return Z_DATA_ERROR;
793
794 /* Setup some variables to allow misuse of updateWindow */
795 z->avail_out = 0;
796 z->next_out = (unsigned char*)z->next_in + z->avail_in;
797
798 zlib_updatewindow(z, z->avail_in);
799
800 /* Restore saved variables */
801 z->avail_out = saved_ao;
802 z->next_out = saved_no;
803
804 z->adler = state->check =
805 UPDATE(state->check, z->next_in, z->avail_in);
806
807 z->total_out += z->avail_in;
808 z->total_in += z->avail_in;
809 z->next_in += z->avail_in;
810 state->total += z->avail_in;
811 z->avail_in = 0;
812
813 return Z_OK;
814 }
815