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
zlib_inflate_workspacesize(void)18 int zlib_inflate_workspacesize(void)
19 {
20 return sizeof(struct inflate_workspace);
21 }
22
zlib_inflateReset(z_streamp strm)23 int zlib_inflateReset(z_streamp strm)
24 {
25 struct inflate_state *state;
26
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;
39
40 /* Initialise Window */
41 state->wsize = 1U << state->wbits;
42 state->write = 0;
43 state->whave = 0;
44
45 return Z_OK;
46 }
47
48 #if 0
49 int zlib_inflatePrime(z_streamp strm, int bits, int value)
50 {
51 struct inflate_state *state;
52
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
62
zlib_inflateInit2(z_streamp strm,int windowBits)63 int zlib_inflateInit2(z_streamp strm, int windowBits)
64 {
65 struct inflate_state *state;
66
67 if (strm == NULL) return Z_STREAM_ERROR;
68 strm->msg = NULL; /* in case we return an error */
69
70 state = &WS(strm)->inflate_state;
71 strm->state = (struct internal_state *)state;
72
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];
85
86 return zlib_inflateReset(strm);
87 }
88
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 */
zlib_fixedtables(struct inflate_state * state)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 }
101
102
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.
109
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 */
zlib_updatewindow(z_streamp strm,unsigned out)116 static void zlib_updatewindow(z_streamp strm, unsigned out)
117 {
118 struct inflate_state *state;
119 unsigned copy, dist;
120
121 state = (struct inflate_state *)strm->state;
122
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 }
147
148
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 */
zlib_inflateSyncPacket(z_streamp strm)161 static int zlib_inflateSyncPacket(z_streamp strm)
162 {
163 struct inflate_state *state;
164
165 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
166 state = (struct inflate_state *)strm->state;
167
168 if (state->mode == STORED && state->bits == 0) {
169 state->mode = TYPE;
170 return Z_OK;
171 }
172 return Z_DATA_ERROR;
173 }
174
175 /* Macros for inflate(): */
176
177 /* check function to use adler32() for zlib or crc32() for gzip */
178 #define UPDATE(check, buf, len) zlib_adler32(check, buf, len)
179
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)
190
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)
201
202 /* Clear the input bit accumulator */
203 #define INITBITS() \
204 do { \
205 hold = 0; \
206 bits = 0; \
207 } while (0)
208
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)
218
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)
226
227 /* Return the low n bits of the bit accumulator (n < 16) */
228 #define BITS(n) \
229 ((unsigned)hold & ((1U << (n)) - 1))
230
231 /* Remove n bits from the bit accumulator */
232 #define DROPBITS(n) \
233 do { \
234 hold >>= (n); \
235 bits -= (unsigned)(n); \
236 } while (0)
237
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)
244
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))
249
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:
254
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 }
265
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:
272
273 NEEDBITS(n);
274 ... do something with BITS(n) ...
275 DROPBITS(n);
276
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.
284
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.
289
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:
295
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:
304
305 As shown above, if the next state is also the next case, then the break
306 is omitted.
307
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.
311
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().
320
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 */
331
zlib_inflate(z_streamp strm,int flush)332 int zlib_inflate(z_streamp strm, int flush)
333 {
334 struct inflate_state *state;
335 const 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};
349
350 /* Do not check for strm->next_out == NULL here as ppc zImage
351 inflates to strm->next_out = 0 */
352
353 if (strm == NULL || strm->state == NULL ||
354 (strm->next_in == NULL && strm->avail_in != 0))
355 return Z_STREAM_ERROR;
356
357 state = (struct inflate_state *)strm->state;
358
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 }
547
548 /* handle error breaks in while */
549 if (state->mode == BAD) break;
550
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 }
724
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);
734
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);
743
744 strm->data_type = state->bits + (state->last ? 64 : 0) +
745 (state->mode == TYPE ? 128 : 0);
746
747 if (flush == Z_PACKET_FLUSH && ret == Z_OK &&
748 strm->avail_out != 0 && strm->avail_in == 0)
749 return zlib_inflateSyncPacket(strm);
750
751 if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
752 ret = Z_BUF_ERROR;
753
754 return ret;
755 }
756
zlib_inflateEnd(z_streamp strm)757 int zlib_inflateEnd(z_streamp strm)
758 {
759 if (strm == NULL || strm->state == NULL)
760 return Z_STREAM_ERROR;
761 return Z_OK;
762 }
763
764 #if 0
765 int zlib_inflateSetDictionary(z_streamp strm, const Byte *dictionary,
766 uInt dictLength)
767 {
768 struct inflate_state *state;
769 unsigned long id;
770
771 /* check state */
772 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
773 state = (struct inflate_state *)strm->state;
774 if (state->wrap != 0 && state->mode != DICT)
775 return Z_STREAM_ERROR;
776
777 /* check for correct dictionary id */
778 if (state->mode == DICT) {
779 id = zlib_adler32(0L, NULL, 0);
780 id = zlib_adler32(id, dictionary, dictLength);
781 if (id != state->check)
782 return Z_DATA_ERROR;
783 }
784
785 /* copy dictionary to window */
786 zlib_updatewindow(strm, strm->avail_out);
787
788 if (dictLength > state->wsize) {
789 memcpy(state->window, dictionary + dictLength - state->wsize,
790 state->wsize);
791 state->whave = state->wsize;
792 }
793 else {
794 memcpy(state->window + state->wsize - dictLength, dictionary,
795 dictLength);
796 state->whave = dictLength;
797 }
798 state->havedict = 1;
799 return Z_OK;
800 }
801 #endif
802
803 #if 0
804 /*
805 Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff. Return when found
806 or when out of input. When called, *have is the number of pattern bytes
807 found in order so far, in 0..3. On return *have is updated to the new
808 state. If on return *have equals four, then the pattern was found and the
809 return value is how many bytes were read including the last byte of the
810 pattern. If *have is less than four, then the pattern has not been found
811 yet and the return value is len. In the latter case, zlib_syncsearch() can be
812 called again with more data and the *have state. *have is initialized to
813 zero for the first call.
814 */
815 static unsigned zlib_syncsearch(unsigned *have, unsigned char *buf,
816 unsigned len)
817 {
818 unsigned got;
819 unsigned next;
820
821 got = *have;
822 next = 0;
823 while (next < len && got < 4) {
824 if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
825 got++;
826 else if (buf[next])
827 got = 0;
828 else
829 got = 4 - got;
830 next++;
831 }
832 *have = got;
833 return next;
834 }
835 #endif
836
837 #if 0
838 int zlib_inflateSync(z_streamp strm)
839 {
840 unsigned len; /* number of bytes to look at or looked at */
841 unsigned long in, out; /* temporary to save total_in and total_out */
842 unsigned char buf[4]; /* to restore bit buffer to byte string */
843 struct inflate_state *state;
844
845 /* check parameters */
846 if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR;
847 state = (struct inflate_state *)strm->state;
848 if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;
849
850 /* if first time, start search in bit buffer */
851 if (state->mode != SYNC) {
852 state->mode = SYNC;
853 state->hold <<= state->bits & 7;
854 state->bits -= state->bits & 7;
855 len = 0;
856 while (state->bits >= 8) {
857 buf[len++] = (unsigned char)(state->hold);
858 state->hold >>= 8;
859 state->bits -= 8;
860 }
861 state->have = 0;
862 zlib_syncsearch(&(state->have), buf, len);
863 }
864
865 /* search available input */
866 len = zlib_syncsearch(&(state->have), strm->next_in, strm->avail_in);
867 strm->avail_in -= len;
868 strm->next_in += len;
869 strm->total_in += len;
870
871 /* return no joy or set up to restart inflate() on a new block */
872 if (state->have != 4) return Z_DATA_ERROR;
873 in = strm->total_in; out = strm->total_out;
874 zlib_inflateReset(strm);
875 strm->total_in = in; strm->total_out = out;
876 state->mode = TYPE;
877 return Z_OK;
878 }
879 #endif
880
881 /*
882 * This subroutine adds the data at next_in/avail_in to the output history
883 * without performing any output. The output buffer must be "caught up";
884 * i.e. no pending output but this should always be the case. The state must
885 * be waiting on the start of a block (i.e. mode == TYPE or HEAD). On exit,
886 * the output will also be caught up, and the checksum will have been updated
887 * if need be.
888 */
zlib_inflateIncomp(z_stream * z)889 int zlib_inflateIncomp(z_stream *z)
890 {
891 struct inflate_state *state = (struct inflate_state *)z->state;
892 Byte *saved_no = z->next_out;
893 uInt saved_ao = z->avail_out;
894
895 if (state->mode != TYPE && state->mode != HEAD)
896 return Z_DATA_ERROR;
897
898 /* Setup some variables to allow misuse of updateWindow */
899 z->avail_out = 0;
900 z->next_out = (unsigned char*)z->next_in + z->avail_in;
901
902 zlib_updatewindow(z, z->avail_in);
903
904 /* Restore saved variables */
905 z->avail_out = saved_ao;
906 z->next_out = saved_no;
907
908 z->adler = state->check =
909 UPDATE(state->check, z->next_in, z->avail_in);
910
911 z->total_out += z->avail_in;
912 z->total_in += z->avail_in;
913 z->next_in += z->avail_in;
914 state->total += z->avail_in;
915 z->avail_in = 0;
916
917 return Z_OK;
918 }
919