1/* inflate.c -- zlib decompression
2 * Copyright (C) 1995-2022 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
4 */
5
6/*
7 * Change history:
8 *
9 * 1.2.beta0 24 Nov 2002
10 * - First version -- complete rewrite of inflate to simplify code, avoid
11 * creation of window when not needed, minimize use of window when it is
12 * needed, make inffast.c even faster, implement gzip decoding, and to
13 * improve code readability and style over the previous zlib inflate code
14 *
15 * 1.2.beta1 25 Nov 2002
16 * - Use pointers for available input and output checking in inffast.c
17 * - Remove input and output counters in inffast.c
18 * - Change inffast.c entry and loop from avail_in >= 7 to >= 6
19 * - Remove unnecessary second byte pull from length extra in inffast.c
20 * - Unroll direct copy to three copies per loop in inffast.c
21 *
22 * 1.2.beta2 4 Dec 2002
23 * - Change external routine names to reduce potential conflicts
24 * - Correct filename to inffixed.h for fixed tables in inflate.c
25 * - Make hbuf[] unsigned char to match parameter type in inflate.c
26 * - Change strm->next_out[-state->offset] to *(strm->next_out - state->offset)
27 * to avoid negation problem on Alphas (64 bit) in inflate.c
28 *
29 * 1.2.beta3 22 Dec 2002
30 * - Add comments on state->bits assertion in inffast.c
31 * - Add comments on op field in inftrees.h
32 * - Fix bug in reuse of allocated window after inflateReset()
33 * - Remove bit fields--back to byte structure for speed
34 * - Remove distance extra == 0 check in inflate_fast()--only helps for lengths
35 * - Change post-increments to pre-increments in inflate_fast(), PPC biased?
36 * - Add compile time option, POSTINC, to use post-increments instead (Intel?)
37 * - Make MATCH copy in inflate() much faster for when inflate_fast() not used
38 * - Use local copies of stream next and avail values, as well as local bit
39 * buffer and bit count in inflate()--for speed when inflate_fast() not used
40 *
41 * 1.2.beta4 1 Jan 2003
42 * - Split ptr - 257 statements in inflate_table() to avoid compiler warnings
43 * - Move a comment on output buffer sizes from inffast.c to inflate.c
44 * - Add comments in inffast.c to introduce the inflate_fast() routine
45 * - Rearrange window copies in inflate_fast() for speed and simplification
46 * - Unroll last copy for window match in inflate_fast()
47 * - Use local copies of window variables in inflate_fast() for speed
48 * - Pull out common wnext == 0 case for speed in inflate_fast()
49 * - Make op and len in inflate_fast() unsigned for consistency
50 * - Add FAR to lcode and dcode declarations in inflate_fast()
51 * - Simplified bad distance check in inflate_fast()
52 * - Added inflateBackInit(), inflateBack(), and inflateBackEnd() in new
53 * source file infback.c to provide a call-back interface to inflate for
54 * programs like gzip and unzip -- uses window as output buffer to avoid
55 * window copying
56 *
57 * 1.2.beta5 1 Jan 2003
58 * - Improved inflateBack() interface to allow the caller to provide initial
59 * input in strm.
60 * - Fixed stored blocks bug in inflateBack()
61 *
62 * 1.2.beta6 4 Jan 2003
63 * - Added comments in inffast.c on effectiveness of POSTINC
64 * - Typecasting all around to reduce compiler warnings
65 * - Changed loops from while (1) or do {} while (1) to for (;;), again to
66 * make compilers happy
67 * - Changed type of window in inflateBackInit() to unsigned char *
68 *
69 * 1.2.beta7 27 Jan 2003
70 * - Changed many types to unsigned or unsigned short to avoid warnings
71 * - Added inflateCopy() function
72 *
73 * 1.2.0 9 Mar 2003
74 * - Changed inflateBack() interface to provide separate opaque descriptors
75 * for the in() and out() functions
76 * - Changed inflateBack() argument and in_func typedef to swap the length
77 * and buffer address return values for the input function
78 * - Check next_in and next_out for Z_NULL on entry to inflate()
79 *
80 * The history for versions after 1.2.0 are in ChangeLog in zlib distribution.
81 */
82
83#include "zutil.h"
84#include "inftrees.h"
85#include "inflate.h"
86#include "inffast.h"
87
88#ifdef MAKEFIXED
89# ifndef BUILDFIXED
90# define BUILDFIXED
91# endif
92#endif
93
94local int inflateStateCheck(z_streamp strm) {
95 struct inflate_state FAR *state;
96 if (strm == Z_NULL ||
97 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
98 return 1;
99 state = (struct inflate_state FAR *)strm->state;
100 if (state == Z_NULL || state->strm != strm ||
101 state->mode < HEAD || state->mode > SYNC)
102 return 1;
103 return 0;
104}
105
106int ZEXPORT inflateResetKeep(z_streamp strm) {
107 struct inflate_state FAR *state;
108
109 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
110 state = (struct inflate_state FAR *)strm->state;
111 strm->total_in = strm->total_out = state->total = 0;
112 strm->msg = Z_NULL;
113 if (state->wrap) /* to support ill-conceived Java test suite */
114 strm->adler = state->wrap & 1;
115 state->mode = HEAD;
116 state->last = 0;
117 state->havedict = 0;
118 state->flags = -1;
119 state->dmax = 32768U;
120 state->head = Z_NULL;
121 state->hold = 0;
122 state->bits = 0;
123 state->lencode = state->distcode = state->next = state->codes;
124 state->sane = 1;
125 state->back = -1;
126 Tracev((stderr, "inflate: reset\n"));
127 return Z_OK;
128}
129
130int ZEXPORT inflateReset(z_streamp strm) {
131 struct inflate_state FAR *state;
132
133 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
134 state = (struct inflate_state FAR *)strm->state;
135 state->wsize = 0;
136 state->whave = 0;
137 state->wnext = 0;
138 return inflateResetKeep(strm);
139}
140
141int ZEXPORT inflateReset2(z_streamp strm, int windowBits) {
142 int wrap;
143 struct inflate_state FAR *state;
144
145 /* get the state */
146 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
147 state = (struct inflate_state FAR *)strm->state;
148
149 /* extract wrap request from windowBits parameter */
150 if (windowBits < 0) {
151 if (windowBits < -15)
152 return Z_STREAM_ERROR;
153 wrap = 0;
154 windowBits = -windowBits;
155 }
156 else {
157 wrap = (windowBits >> 4) + 5;
158#ifdef GUNZIP
159 if (windowBits < 48)
160 windowBits &= 15;
161#endif
162 }
163
164 /* set number of window bits, free window if different */
165 if (windowBits && (windowBits < 8 || windowBits > 15))
166 return Z_STREAM_ERROR;
167 if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
168 ZFREE(strm, state->window);
169 state->window = Z_NULL;
170 }
171
172 /* update state and reset the rest of it */
173 state->wrap = wrap;
174 state->wbits = (unsigned)windowBits;
175 return inflateReset(strm);
176}
177
178int ZEXPORT inflateInit2_(z_streamp strm, int windowBits,
179 const char *version, int stream_size) {
180 int ret;
181 struct inflate_state FAR *state;
182
183 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
184 stream_size != (int)(sizeof(z_stream)))
185 return Z_VERSION_ERROR;
186 if (strm == Z_NULL) return Z_STREAM_ERROR;
187 strm->msg = Z_NULL; /* in case we return an error */
188 if (strm->zalloc == (alloc_func)0) {
189#ifdef Z_SOLO
190 return Z_STREAM_ERROR;
191#else
192 strm->zalloc = zcalloc;
193 strm->opaque = (voidpf)0;
194#endif
195 }
196 if (strm->zfree == (free_func)0)
197#ifdef Z_SOLO
198 return Z_STREAM_ERROR;
199#else
200 strm->zfree = zcfree;
201#endif
202 state = (struct inflate_state FAR *)
203 ZALLOC(strm, 1, sizeof(struct inflate_state));
204 if (state == Z_NULL) return Z_MEM_ERROR;
205 Tracev((stderr, "inflate: allocated\n"));
206 strm->state = (struct internal_state FAR *)state;
207 state->strm = strm;
208 state->window = Z_NULL;
209 state->mode = HEAD; /* to pass state test in inflateReset2() */
210 ret = inflateReset2(strm, windowBits);
211 if (ret != Z_OK) {
212 ZFREE(strm, state);
213 strm->state = Z_NULL;
214 }
215 return ret;
216}
217
218int ZEXPORT inflateInit_(z_streamp strm, const char *version,
219 int stream_size) {
220 return inflateInit2_(strm, DEF_WBITS, version, stream_size);
221}
222
223int ZEXPORT inflatePrime(z_streamp strm, int bits, int value) {
224 struct inflate_state FAR *state;
225
226 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
227 if (bits == 0)
228 return Z_OK;
229 state = (struct inflate_state FAR *)strm->state;
230 if (bits < 0) {
231 state->hold = 0;
232 state->bits = 0;
233 return Z_OK;
234 }
235 if (bits > 16 || state->bits + (uInt)bits > 32) return Z_STREAM_ERROR;
236 value &= (1L << bits) - 1;
237 state->hold += (unsigned)value << state->bits;
238 state->bits += (uInt)bits;
239 return Z_OK;
240}
241
242/*
243 Return state with length and distance decoding tables and index sizes set to
244 fixed code decoding. Normally this returns fixed tables from inffixed.h.
245 If BUILDFIXED is defined, then instead this routine builds the tables the
246 first time it's called, and returns those tables the first time and
247 thereafter. This reduces the size of the code by about 2K bytes, in
248 exchange for a little execution time. However, BUILDFIXED should not be
249 used for threaded applications, since the rewriting of the tables and virgin
250 may not be thread-safe.
251 */
252local void fixedtables(struct inflate_state FAR *state) {
253#ifdef BUILDFIXED
254 static int virgin = 1;
255 static code *lenfix, *distfix;
256 static code fixed[544];
257
258 /* build fixed huffman tables if first call (may not be thread safe) */
259 if (virgin) {
260 unsigned sym, bits;
261 static code *next;
262
263 /* literal/length table */
264 sym = 0;
265 while (sym < 144) state->lens[sym++] = 8;
266 while (sym < 256) state->lens[sym++] = 9;
267 while (sym < 280) state->lens[sym++] = 7;
268 while (sym < 288) state->lens[sym++] = 8;
269 next = fixed;
270 lenfix = next;
271 bits = 9;
272 inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
273
274 /* distance table */
275 sym = 0;
276 while (sym < 32) state->lens[sym++] = 5;
277 distfix = next;
278 bits = 5;
279 inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
280
281 /* do this just once */
282 virgin = 0;
283 }
284#else /* !BUILDFIXED */
285# include "inffixed.h"
286#endif /* BUILDFIXED */
287 state->lencode = lenfix;
288 state->lenbits = 9;
289 state->distcode = distfix;
290 state->distbits = 5;
291}
292
293#ifdef MAKEFIXED
294#include <stdio.h>
295
296/*
297 Write out the inffixed.h that is #include'd above. Defining MAKEFIXED also
298 defines BUILDFIXED, so the tables are built on the fly. makefixed() writes
299 those tables to stdout, which would be piped to inffixed.h. A small program
300 can simply call makefixed to do this:
301
302 void makefixed(void);
303
304 int main(void)
305 {
306 makefixed();
307 return 0;
308 }
309
310 Then that can be linked with zlib built with MAKEFIXED defined and run:
311
312 a.out > inffixed.h
313 */
314void makefixed(void)
315{
316 unsigned low, size;
317 struct inflate_state state;
318
319 fixedtables(&state);
320 puts(" /* inffixed.h -- table for decoding fixed codes");
321 puts(" * Generated automatically by makefixed().");
322 puts(" */");
323 puts("");
324 puts(" /* WARNING: this file should *not* be used by applications.");
325 puts(" It is part of the implementation of this library and is");
326 puts(" subject to change. Applications should only use zlib.h.");
327 puts(" */");
328 puts("");
329 size = 1U << 9;
330 printf(" static const code lenfix[%u] = {", size);
331 low = 0;
332 for (;;) {
333 if ((low % 7) == 0) printf("\n ");
334 printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,
335 state.lencode[low].bits, state.lencode[low].val);
336 if (++low == size) break;
337 putchar(',');
338 }
339 puts("\n };");
340 size = 1U << 5;
341 printf("\n static const code distfix[%u] = {", size);
342 low = 0;
343 for (;;) {
344 if ((low % 6) == 0) printf("\n ");
345 printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits,
346 state.distcode[low].val);
347 if (++low == size) break;
348 putchar(',');
349 }
350 puts("\n };");
351}
352#endif /* MAKEFIXED */
353
354/*
355 Update the window with the last wsize (normally 32K) bytes written before
356 returning. If window does not exist yet, create it. This is only called
357 when a window is already in use, or when output has been written during this
358 inflate call, but the end of the deflate stream has not been reached yet.
359 It is also called to create a window for dictionary data when a dictionary
360 is loaded.
361
362 Providing output buffers larger than 32K to inflate() should provide a speed
363 advantage, since only the last 32K of output is copied to the sliding window
364 upon return from inflate(), and since all distances after the first 32K of
365 output will fall in the output data, making match copies simpler and faster.
366 The advantage may be dependent on the size of the processor's data caches.
367 */
368local int updatewindow(z_streamp strm, const Bytef *end, unsigned copy) {
369 struct inflate_state FAR *state;
370 unsigned dist;
371
372 state = (struct inflate_state FAR *)strm->state;
373
374 /* if it hasn't been done already, allocate space for the window */
375 if (state->window == Z_NULL) {
376 state->window = (unsigned char FAR *)
377 ZALLOC(strm, 1U << state->wbits,
378 sizeof(unsigned char));
379 if (state->window == Z_NULL) return 1;
380 }
381
382 /* if window not in use yet, initialize */
383 if (state->wsize == 0) {
384 state->wsize = 1U << state->wbits;
385 state->wnext = 0;
386 state->whave = 0;
387 }
388
389 /* copy state->wsize or less output bytes into the circular window */
390 if (copy >= state->wsize) {
391 zmemcpy(state->window, end - state->wsize, state->wsize);
392 state->wnext = 0;
393 state->whave = state->wsize;
394 }
395 else {
396 dist = state->wsize - state->wnext;
397 if (dist > copy) dist = copy;
398 zmemcpy(state->window + state->wnext, end - copy, dist);
399 copy -= dist;
400 if (copy) {
401 zmemcpy(state->window, end - copy, copy);
402 state->wnext = copy;
403 state->whave = state->wsize;
404 }
405 else {
406 state->wnext += dist;
407 if (state->wnext == state->wsize) state->wnext = 0;
408 if (state->whave < state->wsize) state->whave += dist;
409 }
410 }
411 return 0;
412}
413
414/* Macros for inflate(): */
415
416/* check function to use adler32() for zlib or crc32() for gzip */
417#ifdef GUNZIP
418# define UPDATE_CHECK(check, buf, len) \
419 (state->flags ? crc32(check, buf, len) : adler32(check, buf, len))
420#else
421# define UPDATE_CHECK(check, buf, len) adler32(check, buf, len)
422#endif
423
424/* check macros for header crc */
425#ifdef GUNZIP
426# define CRC2(check, word) \
427 do { \
428 hbuf[0] = (unsigned char)(word); \
429 hbuf[1] = (unsigned char)((word) >> 8); \
430 check = crc32(check, hbuf, 2); \
431 } while (0)
432
433# define CRC4(check, word) \
434 do { \
435 hbuf[0] = (unsigned char)(word); \
436 hbuf[1] = (unsigned char)((word) >> 8); \
437 hbuf[2] = (unsigned char)((word) >> 16); \
438 hbuf[3] = (unsigned char)((word) >> 24); \
439 check = crc32(check, hbuf, 4); \
440 } while (0)
441#endif
442
443/* Load registers with state in inflate() for speed */
444#define LOAD() \
445 do { \
446 put = strm->next_out; \
447 left = strm->avail_out; \
448 next = strm->next_in; \
449 have = strm->avail_in; \
450 hold = state->hold; \
451 bits = state->bits; \
452 } while (0)
453
454/* Restore state from registers in inflate() */
455#define RESTORE() \
456 do { \
457 strm->next_out = put; \
458 strm->avail_out = left; \
459 strm->next_in = next; \
460 strm->avail_in = have; \
461 state->hold = hold; \
462 state->bits = bits; \
463 } while (0)
464
465/* Clear the input bit accumulator */
466#define INITBITS() \
467 do { \
468 hold = 0; \
469 bits = 0; \
470 } while (0)
471
472/* Get a byte of input into the bit accumulator, or return from inflate()
473 if there is no input available. */
474#define PULLBYTE() \
475 do { \
476 if (have == 0) goto inf_leave; \
477 have--; \
478 hold += (unsigned long)(*next++) << bits; \
479 bits += 8; \
480 } while (0)
481
482/* Assure that there are at least n bits in the bit accumulator. If there is
483 not enough available input to do that, then return from inflate(). */
484#define NEEDBITS(n) \
485 do { \
486 while (bits < (unsigned)(n)) \
487 PULLBYTE(); \
488 } while (0)
489
490/* Return the low n bits of the bit accumulator (n < 16) */
491#define BITS(n) \
492 ((unsigned)hold & ((1U << (n)) - 1))
493
494/* Remove n bits from the bit accumulator */
495#define DROPBITS(n) \
496 do { \
497 hold >>= (n); \
498 bits -= (unsigned)(n); \
499 } while (0)
500
501/* Remove zero to seven bits as needed to go to a byte boundary */
502#define BYTEBITS() \
503 do { \
504 hold >>= bits & 7; \
505 bits -= bits & 7; \
506 } while (0)
507
508/*
509 inflate() uses a state machine to process as much input data and generate as
510 much output data as possible before returning. The state machine is
511 structured roughly as follows:
512
513 for (;;) switch (state) {
514 ...
515 case STATEn:
516 if (not enough input data or output space to make progress)
517 return;
518 ... make progress ...
519 state = STATEm;
520 break;
521 ...
522 }
523
524 so when inflate() is called again, the same case is attempted again, and
525 if the appropriate resources are provided, the machine proceeds to the
526 next state. The NEEDBITS() macro is usually the way the state evaluates
527 whether it can proceed or should return. NEEDBITS() does the return if
528 the requested bits are not available. The typical use of the BITS macros
529 is:
530
531 NEEDBITS(n);
532 ... do something with BITS(n) ...
533 DROPBITS(n);
534
535 where NEEDBITS(n) either returns from inflate() if there isn't enough
536 input left to load n bits into the accumulator, or it continues. BITS(n)
537 gives the low n bits in the accumulator. When done, DROPBITS(n) drops
538 the low n bits off the accumulator. INITBITS() clears the accumulator
539 and sets the number of available bits to zero. BYTEBITS() discards just
540 enough bits to put the accumulator on a byte boundary. After BYTEBITS()
541 and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
542
543 NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
544 if there is no input available. The decoding of variable length codes uses
545 PULLBYTE() directly in order to pull just enough bytes to decode the next
546 code, and no more.
547
548 Some states loop until they get enough input, making sure that enough
549 state information is maintained to continue the loop where it left off
550 if NEEDBITS() returns in the loop. For example, want, need, and keep
551 would all have to actually be part of the saved state in case NEEDBITS()
552 returns:
553
554 case STATEw:
555 while (want < need) {
556 NEEDBITS(n);
557 keep[want++] = BITS(n);
558 DROPBITS(n);
559 }
560 state = STATEx;
561 case STATEx:
562
563 As shown above, if the next state is also the next case, then the break
564 is omitted.
565
566 A state may also return if there is not enough output space available to
567 complete that state. Those states are copying stored data, writing a
568 literal byte, and copying a matching string.
569
570 When returning, a "goto inf_leave" is used to update the total counters,
571 update the check value, and determine whether any progress has been made
572 during that inflate() call in order to return the proper return code.
573 Progress is defined as a change in either strm->avail_in or strm->avail_out.
574 When there is a window, goto inf_leave will update the window with the last
575 output written. If a goto inf_leave occurs in the middle of decompression
576 and there is no window currently, goto inf_leave will create one and copy
577 output to the window for the next call of inflate().
578
579 In this implementation, the flush parameter of inflate() only affects the
580 return code (per zlib.h). inflate() always writes as much as possible to
581 strm->next_out, given the space available and the provided input--the effect
582 documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers
583 the allocation of and copying into a sliding window until necessary, which
584 provides the effect documented in zlib.h for Z_FINISH when the entire input
585 stream available. So the only thing the flush parameter actually does is:
586 when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it
587 will return Z_BUF_ERROR if it has not reached the end of the stream.
588 */
589
590int ZEXPORT inflate(z_streamp strm, int flush) {
591 struct inflate_state FAR *state;
592 z_const unsigned char FAR *next; /* next input */
593 unsigned char FAR *put; /* next output */
594 unsigned have, left; /* available input and output */
595 unsigned long hold; /* bit buffer */
596 unsigned bits; /* bits in bit buffer */
597 unsigned in, out; /* save starting available input and output */
598 unsigned copy; /* number of stored or match bytes to copy */
599 unsigned char FAR *from; /* where to copy match bytes from */
600 code here; /* current decoding table entry */
601 code last; /* parent table entry */
602 unsigned len; /* length to copy for repeats, bits to drop */
603 int ret; /* return code */
604#ifdef GUNZIP
605 unsigned char hbuf[4]; /* buffer for gzip header crc calculation */
606#endif
607 static const unsigned short order[19] = /* permutation of code lengths */
608 {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
609
610 if (inflateStateCheck(strm) || strm->next_out == Z_NULL ||
611 (strm->next_in == Z_NULL && strm->avail_in != 0))
612 return Z_STREAM_ERROR;
613
614 state = (struct inflate_state FAR *)strm->state;
615 if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */
616 LOAD();
617 in = have;
618 out = left;
619 ret = Z_OK;
620 for (;;)
621 switch (state->mode) {
622 case HEAD:
623 if (state->wrap == 0) {
624 state->mode = TYPEDO;
625 break;
626 }
627 NEEDBITS(16);
628#ifdef GUNZIP
629 if ((state->wrap & 2) && hold == 0x8b1f) { /* gzip header */
630 if (state->wbits == 0)
631 state->wbits = 15;
632 state->check = crc32(0L, Z_NULL, 0);
633 CRC2(state->check, hold);
634 INITBITS();
635 state->mode = FLAGS;
636 break;
637 }
638 if (state->head != Z_NULL)
639 state->head->done = -1;
640 if (!(state->wrap & 1) || /* check if zlib header allowed */
641#else
642 if (
643#endif
644 ((BITS(8) << 8) + (hold >> 8)) % 31) {
645 strm->msg = (char *)"incorrect header check";
646 state->mode = BAD;
647 break;
648 }
649 if (BITS(4) != Z_DEFLATED) {
650 strm->msg = (char *)"unknown compression method";
651 state->mode = BAD;
652 break;
653 }
654 DROPBITS(4);
655 len = BITS(4) + 8;
656 if (state->wbits == 0)
657 state->wbits = len;
658 if (len > 15 || len > state->wbits) {
659 strm->msg = (char *)"invalid window size";
660 state->mode = BAD;
661 break;
662 }
663 state->dmax = 1U << len;
664 state->flags = 0; /* indicate zlib header */
665 Tracev((stderr, "inflate: zlib header ok\n"));
666 strm->adler = state->check = adler32(0L, Z_NULL, 0);
667 state->mode = hold & 0x200 ? DICTID : TYPE;
668 INITBITS();
669 break;
670#ifdef GUNZIP
671 case FLAGS:
672 NEEDBITS(16);
673 state->flags = (int)(hold);
674 if ((state->flags & 0xff) != Z_DEFLATED) {
675 strm->msg = (char *)"unknown compression method";
676 state->mode = BAD;
677 break;
678 }
679 if (state->flags & 0xe000) {
680 strm->msg = (char *)"unknown header flags set";
681 state->mode = BAD;
682 break;
683 }
684 if (state->head != Z_NULL)
685 state->head->text = (int)((hold >> 8) & 1);
686 if ((state->flags & 0x0200) && (state->wrap & 4))
687 CRC2(state->check, hold);
688 INITBITS();
689 state->mode = TIME;
690 /* fallthrough */
691 case TIME:
692 NEEDBITS(32);
693 if (state->head != Z_NULL)
694 state->head->time = hold;
695 if ((state->flags & 0x0200) && (state->wrap & 4))
696 CRC4(state->check, hold);
697 INITBITS();
698 state->mode = OS;
699 /* fallthrough */
700 case OS:
701 NEEDBITS(16);
702 if (state->head != Z_NULL) {
703 state->head->xflags = (int)(hold & 0xff);
704 state->head->os = (int)(hold >> 8);
705 }
706 if ((state->flags & 0x0200) && (state->wrap & 4))
707 CRC2(state->check, hold);
708 INITBITS();
709 state->mode = EXLEN;
710 /* fallthrough */
711 case EXLEN:
712 if (state->flags & 0x0400) {
713 NEEDBITS(16);
714 state->length = (unsigned)(hold);
715 if (state->head != Z_NULL)
716 state->head->extra_len = (unsigned)hold;
717 if ((state->flags & 0x0200) && (state->wrap & 4))
718 CRC2(state->check, hold);
719 INITBITS();
720 }
721 else if (state->head != Z_NULL)
722 state->head->extra = Z_NULL;
723 state->mode = EXTRA;
724 /* fallthrough */
725 case EXTRA:
726 if (state->flags & 0x0400) {
727 copy = state->length;
728 if (copy > have) copy = have;
729 if (copy) {
730 if (state->head != Z_NULL &&
731 state->head->extra != Z_NULL &&
732 (len = state->head->extra_len - state->length) <
733 state->head->extra_max) {
734 zmemcpy(state->head->extra + len, next,
735 len + copy > state->head->extra_max ?
736 state->head->extra_max - len : copy);
737 }
738 if ((state->flags & 0x0200) && (state->wrap & 4))
739 state->check = crc32(state->check, next, copy);
740 have -= copy;
741 next += copy;
742 state->length -= copy;
743 }
744 if (state->length) goto inf_leave;
745 }
746 state->length = 0;
747 state->mode = NAME;
748 /* fallthrough */
749 case NAME:
750 if (state->flags & 0x0800) {
751 if (have == 0) goto inf_leave;
752 copy = 0;
753 do {
754 len = (unsigned)(next[copy++]);
755 if (state->head != Z_NULL &&
756 state->head->name != Z_NULL &&
757 state->length < state->head->name_max)
758 state->head->name[state->length++] = (Bytef)len;
759 } while (len && copy < have);
760 if ((state->flags & 0x0200) && (state->wrap & 4))
761 state->check = crc32(state->check, next, copy);
762 have -= copy;
763 next += copy;
764 if (len) goto inf_leave;
765 }
766 else if (state->head != Z_NULL)
767 state->head->name = Z_NULL;
768 state->length = 0;
769 state->mode = COMMENT;
770 /* fallthrough */
771 case COMMENT:
772 if (state->flags & 0x1000) {
773 if (have == 0) goto inf_leave;
774 copy = 0;
775 do {
776 len = (unsigned)(next[copy++]);
777 if (state->head != Z_NULL &&
778 state->head->comment != Z_NULL &&
779 state->length < state->head->comm_max)
780 state->head->comment[state->length++] = (Bytef)len;
781 } while (len && copy < have);
782 if ((state->flags & 0x0200) && (state->wrap & 4))
783 state->check = crc32(state->check, next, copy);
784 have -= copy;
785 next += copy;
786 if (len) goto inf_leave;
787 }
788 else if (state->head != Z_NULL)
789 state->head->comment = Z_NULL;
790 state->mode = HCRC;
791 /* fallthrough */
792 case HCRC:
793 if (state->flags & 0x0200) {
794 NEEDBITS(16);
795 if ((state->wrap & 4) && hold != (state->check & 0xffff)) {
796 strm->msg = (char *)"header crc mismatch";
797 state->mode = BAD;
798 break;
799 }
800 INITBITS();
801 }
802 if (state->head != Z_NULL) {
803 state->head->hcrc = (int)((state->flags >> 9) & 1);
804 state->head->done = 1;
805 }
806 strm->adler = state->check = crc32(0L, Z_NULL, 0);
807 state->mode = TYPE;
808 break;
809#endif
810 case DICTID:
811 NEEDBITS(32);
812 strm->adler = state->check = ZSWAP32(hold);
813 INITBITS();
814 state->mode = DICT;
815 /* fallthrough */
816 case DICT:
817 if (state->havedict == 0) {
818 RESTORE();
819 return Z_NEED_DICT;
820 }
821 strm->adler = state->check = adler32(0L, Z_NULL, 0);
822 state->mode = TYPE;
823 /* fallthrough */
824 case TYPE:
825 if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
826 /* fallthrough */
827 case TYPEDO:
828 if (state->last) {
829 BYTEBITS();
830 state->mode = CHECK;
831 break;
832 }
833 NEEDBITS(3);
834 state->last = BITS(1);
835 DROPBITS(1);
836 switch (BITS(2)) {
837 case 0: /* stored block */
838 Tracev((stderr, "inflate: stored block%s\n",
839 state->last ? " (last)" : ""));
840 state->mode = STORED;
841 break;
842 case 1: /* fixed block */
843 fixedtables(state);
844 Tracev((stderr, "inflate: fixed codes block%s\n",
845 state->last ? " (last)" : ""));
846 state->mode = LEN_; /* decode codes */
847 if (flush == Z_TREES) {
848 DROPBITS(2);
849 goto inf_leave;
850 }
851 break;
852 case 2: /* dynamic block */
853 Tracev((stderr, "inflate: dynamic codes block%s\n",
854 state->last ? " (last)" : ""));
855 state->mode = TABLE;
856 break;
857 case 3:
858 strm->msg = (char *)"invalid block type";
859 state->mode = BAD;
860 }
861 DROPBITS(2);
862 break;
863 case STORED:
864 BYTEBITS(); /* go to byte boundary */
865 NEEDBITS(32);
866 if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
867 strm->msg = (char *)"invalid stored block lengths";
868 state->mode = BAD;
869 break;
870 }
871 state->length = (unsigned)hold & 0xffff;
872 Tracev((stderr, "inflate: stored length %u\n",
873 state->length));
874 INITBITS();
875 state->mode = COPY_;
876 if (flush == Z_TREES) goto inf_leave;
877 /* fallthrough */
878 case COPY_:
879 state->mode = COPY;
880 /* fallthrough */
881 case COPY:
882 copy = state->length;
883 if (copy) {
884 if (copy > have) copy = have;
885 if (copy > left) copy = left;
886 if (copy == 0) goto inf_leave;
887 zmemcpy(put, next, copy);
888 have -= copy;
889 next += copy;
890 left -= copy;
891 put += copy;
892 state->length -= copy;
893 break;
894 }
895 Tracev((stderr, "inflate: stored end\n"));
896 state->mode = TYPE;
897 break;
898 case TABLE:
899 NEEDBITS(14);
900 state->nlen = BITS(5) + 257;
901 DROPBITS(5);
902 state->ndist = BITS(5) + 1;
903 DROPBITS(5);
904 state->ncode = BITS(4) + 4;
905 DROPBITS(4);
906#ifndef PKZIP_BUG_WORKAROUND
907 if (state->nlen > 286 || state->ndist > 30) {
908 strm->msg = (char *)"too many length or distance symbols";
909 state->mode = BAD;
910 break;
911 }
912#endif
913 Tracev((stderr, "inflate: table sizes ok\n"));
914 state->have = 0;
915 state->mode = LENLENS;
916 /* fallthrough */
917 case LENLENS:
918 while (state->have < state->ncode) {
919 NEEDBITS(3);
920 state->lens[order[state->have++]] = (unsigned short)BITS(3);
921 DROPBITS(3);
922 }
923 while (state->have < 19)
924 state->lens[order[state->have++]] = 0;
925 state->next = state->codes;
926 state->lencode = (const code FAR *)(state->next);
927 state->lenbits = 7;
928 ret = inflate_table(CODES, state->lens, 19, &(state->next),
929 &(state->lenbits), state->work);
930 if (ret) {
931 strm->msg = (char *)"invalid code lengths set";
932 state->mode = BAD;
933 break;
934 }
935 Tracev((stderr, "inflate: code lengths ok\n"));
936 state->have = 0;
937 state->mode = CODELENS;
938 /* fallthrough */
939 case CODELENS:
940 while (state->have < state->nlen + state->ndist) {
941 for (;;) {
942 here = state->lencode[BITS(state->lenbits)];
943 if ((unsigned)(here.bits) <= bits) break;
944 PULLBYTE();
945 }
946 if (here.val < 16) {
947 DROPBITS(here.bits);
948 state->lens[state->have++] = here.val;
949 }
950 else {
951 if (here.val == 16) {
952 NEEDBITS(here.bits + 2);
953 DROPBITS(here.bits);
954 if (state->have == 0) {
955 strm->msg = (char *)"invalid bit length repeat";
956 state->mode = BAD;
957 break;
958 }
959 len = state->lens[state->have - 1];
960 copy = 3 + BITS(2);
961 DROPBITS(2);
962 }
963 else if (here.val == 17) {
964 NEEDBITS(here.bits + 3);
965 DROPBITS(here.bits);
966 len = 0;
967 copy = 3 + BITS(3);
968 DROPBITS(3);
969 }
970 else {
971 NEEDBITS(here.bits + 7);
972 DROPBITS(here.bits);
973 len = 0;
974 copy = 11 + BITS(7);
975 DROPBITS(7);
976 }
977 if (state->have + copy > state->nlen + state->ndist) {
978 strm->msg = (char *)"invalid bit length repeat";
979 state->mode = BAD;
980 break;
981 }
982 while (copy--)
983 state->lens[state->have++] = (unsigned short)len;
984 }
985 }
986
987 /* handle error breaks in while */
988 if (state->mode == BAD) break;
989
990 /* check for end-of-block code (better have one) */
991 if (state->lens[256] == 0) {
992 strm->msg = (char *)"invalid code -- missing end-of-block";
993 state->mode = BAD;
994 break;
995 }
996
997 /* build code tables -- note: do not change the lenbits or distbits
998 values here (9 and 6) without reading the comments in inftrees.h
999 concerning the ENOUGH constants, which depend on those values */
1000 state->next = state->codes;
1001 state->lencode = (const code FAR *)(state->next);
1002 state->lenbits = 9;
1003 ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
1004 &(state->lenbits), state->work);
1005 if (ret) {
1006 strm->msg = (char *)"invalid literal/lengths set";
1007 state->mode = BAD;
1008 break;
1009 }
1010 state->distcode = (const code FAR *)(state->next);
1011 state->distbits = 6;
1012 ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
1013 &(state->next), &(state->distbits), state->work);
1014 if (ret) {
1015 strm->msg = (char *)"invalid distances set";
1016 state->mode = BAD;
1017 break;
1018 }
1019 Tracev((stderr, "inflate: codes ok\n"));
1020 state->mode = LEN_;
1021 if (flush == Z_TREES) goto inf_leave;
1022 /* fallthrough */
1023 case LEN_:
1024 state->mode = LEN;
1025 /* fallthrough */
1026 case LEN:
1027 if (have >= 6 && left >= 258) {
1028 RESTORE();
1029 inflate_fast(strm, out);
1030 LOAD();
1031 if (state->mode == TYPE)
1032 state->back = -1;
1033 break;
1034 }
1035 state->back = 0;
1036 for (;;) {
1037 here = state->lencode[BITS(state->lenbits)];
1038 if ((unsigned)(here.bits) <= bits) break;
1039 PULLBYTE();
1040 }
1041 if (here.op && (here.op & 0xf0) == 0) {
1042 last = here;
1043 for (;;) {
1044 here = state->lencode[last.val +
1045 (BITS(last.bits + last.op) >> last.bits)];
1046 if ((unsigned)(last.bits + here.bits) <= bits) break;
1047 PULLBYTE();
1048 }
1049 DROPBITS(last.bits);
1050 state->back += last.bits;
1051 }
1052 DROPBITS(here.bits);
1053 state->back += here.bits;
1054 state->length = (unsigned)here.val;
1055 if ((int)(here.op) == 0) {
1056 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
1057 "inflate: literal '%c'\n" :
1058 "inflate: literal 0x%02x\n", here.val));
1059 state->mode = LIT;
1060 break;
1061 }
1062 if (here.op & 32) {
1063 Tracevv((stderr, "inflate: end of block\n"));
1064 state->back = -1;
1065 state->mode = TYPE;
1066 break;
1067 }
1068 if (here.op & 64) {
1069 strm->msg = (char *)"invalid literal/length code";
1070 state->mode = BAD;
1071 break;
1072 }
1073 state->extra = (unsigned)(here.op) & 15;
1074 state->mode = LENEXT;
1075 /* fallthrough */
1076 case LENEXT:
1077 if (state->extra) {
1078 NEEDBITS(state->extra);
1079 state->length += BITS(state->extra);
1080 DROPBITS(state->extra);
1081 state->back += state->extra;
1082 }
1083 Tracevv((stderr, "inflate: length %u\n", state->length));
1084 state->was = state->length;
1085 state->mode = DIST;
1086 /* fallthrough */
1087 case DIST:
1088 for (;;) {
1089 here = state->distcode[BITS(state->distbits)];
1090 if ((unsigned)(here.bits) <= bits) break;
1091 PULLBYTE();
1092 }
1093 if ((here.op & 0xf0) == 0) {
1094 last = here;
1095 for (;;) {
1096 here = state->distcode[last.val +
1097 (BITS(last.bits + last.op) >> last.bits)];
1098 if ((unsigned)(last.bits + here.bits) <= bits) break;
1099 PULLBYTE();
1100 }
1101 DROPBITS(last.bits);
1102 state->back += last.bits;
1103 }
1104 DROPBITS(here.bits);
1105 state->back += here.bits;
1106 if (here.op & 64) {
1107 strm->msg = (char *)"invalid distance code";
1108 state->mode = BAD;
1109 break;
1110 }
1111 state->offset = (unsigned)here.val;
1112 state->extra = (unsigned)(here.op) & 15;
1113 state->mode = DISTEXT;
1114 /* fallthrough */
1115 case DISTEXT:
1116 if (state->extra) {
1117 NEEDBITS(state->extra);
1118 state->offset += BITS(state->extra);
1119 DROPBITS(state->extra);
1120 state->back += state->extra;
1121 }
1122#ifdef INFLATE_STRICT
1123 if (state->offset > state->dmax) {
1124 strm->msg = (char *)"invalid distance too far back";
1125 state->mode = BAD;
1126 break;
1127 }
1128#endif
1129 Tracevv((stderr, "inflate: distance %u\n", state->offset));
1130 state->mode = MATCH;
1131 /* fallthrough */
1132 case MATCH:
1133 if (left == 0) goto inf_leave;
1134 copy = out - left;
1135 if (state->offset > copy) { /* copy from window */
1136 copy = state->offset - copy;
1137 if (copy > state->whave) {
1138 if (state->sane) {
1139 strm->msg = (char *)"invalid distance too far back";
1140 state->mode = BAD;
1141 break;
1142 }
1143#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
1144 Trace((stderr, "inflate.c too far\n"));
1145 copy -= state->whave;
1146 if (copy > state->length) copy = state->length;
1147 if (copy > left) copy = left;
1148 left -= copy;
1149 state->length -= copy;
1150 do {
1151 *put++ = 0;
1152 } while (--copy);
1153 if (state->length == 0) state->mode = LEN;
1154 break;
1155#endif
1156 }
1157 if (copy > state->wnext) {
1158 copy -= state->wnext;
1159 from = state->window + (state->wsize - copy);
1160 }
1161 else
1162 from = state->window + (state->wnext - copy);
1163 if (copy > state->length) copy = state->length;
1164 }
1165 else { /* copy from output */
1166 from = put - state->offset;
1167 copy = state->length;
1168 }
1169 if (copy > left) copy = left;
1170 left -= copy;
1171 state->length -= copy;
1172 do {
1173 *put++ = *from++;
1174 } while (--copy);
1175 if (state->length == 0) state->mode = LEN;
1176 break;
1177 case LIT:
1178 if (left == 0) goto inf_leave;
1179 *put++ = (unsigned char)(state->length);
1180 left--;
1181 state->mode = LEN;
1182 break;
1183 case CHECK:
1184 if (state->wrap) {
1185 NEEDBITS(32);
1186 out -= left;
1187 strm->total_out += out;
1188 state->total += out;
1189 if ((state->wrap & 4) && out)
1190 strm->adler = state->check =
1191 UPDATE_CHECK(state->check, put - out, out);
1192 out = left;
1193 if ((state->wrap & 4) && (
1194#ifdef GUNZIP
1195 state->flags ? hold :
1196#endif
1197 ZSWAP32(hold)) != state->check) {
1198 strm->msg = (char *)"incorrect data check";
1199 state->mode = BAD;
1200 break;
1201 }
1202 INITBITS();
1203 Tracev((stderr, "inflate: check matches trailer\n"));
1204 }
1205#ifdef GUNZIP
1206 state->mode = LENGTH;
1207 /* fallthrough */
1208 case LENGTH:
1209 if (state->wrap && state->flags) {
1210 NEEDBITS(32);
1211 if ((state->wrap & 4) && hold != (state->total & 0xffffffff)) {
1212 strm->msg = (char *)"incorrect length check";
1213 state->mode = BAD;
1214 break;
1215 }
1216 INITBITS();
1217 Tracev((stderr, "inflate: length matches trailer\n"));
1218 }
1219#endif
1220 state->mode = DONE;
1221 /* fallthrough */
1222 case DONE:
1223 ret = Z_STREAM_END;
1224 goto inf_leave;
1225 case BAD:
1226 ret = Z_DATA_ERROR;
1227 goto inf_leave;
1228 case MEM:
1229 return Z_MEM_ERROR;
1230 case SYNC:
1231 /* fallthrough */
1232 default:
1233 return Z_STREAM_ERROR;
1234 }
1235
1236 /*
1237 Return from inflate(), updating the total counts and the check value.
1238 If there was no progress during the inflate() call, return a buffer
1239 error. Call updatewindow() to create and/or update the window state.
1240 Note: a memory error from inflate() is non-recoverable.
1241 */
1242 inf_leave:
1243 RESTORE();
1244 if (state->wsize || (out != strm->avail_out && state->mode < BAD &&
1245 (state->mode < CHECK || flush != Z_FINISH)))
1246 if (updatewindow(strm, strm->next_out, out - strm->avail_out)) {
1247 state->mode = MEM;
1248 return Z_MEM_ERROR;
1249 }
1250 in -= strm->avail_in;
1251 out -= strm->avail_out;
1252 strm->total_in += in;
1253 strm->total_out += out;
1254 state->total += out;
1255 if ((state->wrap & 4) && out)
1256 strm->adler = state->check =
1257 UPDATE_CHECK(state->check, strm->next_out - out, out);
1258 strm->data_type = (int)state->bits + (state->last ? 64 : 0) +
1259 (state->mode == TYPE ? 128 : 0) +
1260 (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
1261 if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
1262 ret = Z_BUF_ERROR;
1263 return ret;
1264}
1265
1266int ZEXPORT inflateEnd(z_streamp strm) {
1267 struct inflate_state FAR *state;
1268 if (inflateStateCheck(strm))
1269 return Z_STREAM_ERROR;
1270 state = (struct inflate_state FAR *)strm->state;
1271 if (state->window != Z_NULL) ZFREE(strm, state->window);
1272 ZFREE(strm, strm->state);
1273 strm->state = Z_NULL;
1274 Tracev((stderr, "inflate: end\n"));
1275 return Z_OK;
1276}
1277
1278int ZEXPORT inflateGetDictionary(z_streamp strm, Bytef *dictionary,
1279 uInt *dictLength) {
1280 struct inflate_state FAR *state;
1281
1282 /* check state */
1283 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1284 state = (struct inflate_state FAR *)strm->state;
1285
1286 /* copy dictionary */
1287 if (state->whave && dictionary != Z_NULL) {
1288 zmemcpy(dictionary, state->window + state->wnext,
1289 state->whave - state->wnext);
1290 zmemcpy(dictionary + state->whave - state->wnext,
1291 state->window, state->wnext);
1292 }
1293 if (dictLength != Z_NULL)
1294 *dictLength = state->whave;
1295 return Z_OK;
1296}
1297
1298int ZEXPORT inflateSetDictionary(z_streamp strm, const Bytef *dictionary,
1299 uInt dictLength) {
1300 struct inflate_state FAR *state;
1301 unsigned long dictid;
1302 int ret;
1303
1304 /* check state */
1305 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1306 state = (struct inflate_state FAR *)strm->state;
1307 if (state->wrap != 0 && state->mode != DICT)
1308 return Z_STREAM_ERROR;
1309
1310 /* check for correct dictionary identifier */
1311 if (state->mode == DICT) {
1312 dictid = adler32(0L, Z_NULL, 0);
1313 dictid = adler32(dictid, dictionary, dictLength);
1314 if (dictid != state->check)
1315 return Z_DATA_ERROR;
1316 }
1317
1318 /* copy dictionary to window using updatewindow(), which will amend the
1319 existing dictionary if appropriate */
1320 ret = updatewindow(strm, dictionary + dictLength, dictLength);
1321 if (ret) {
1322 state->mode = MEM;
1323 return Z_MEM_ERROR;
1324 }
1325 state->havedict = 1;
1326 Tracev((stderr, "inflate: dictionary set\n"));
1327 return Z_OK;
1328}
1329
1330int ZEXPORT inflateGetHeader(z_streamp strm, gz_headerp head) {
1331 struct inflate_state FAR *state;
1332
1333 /* check state */
1334 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1335 state = (struct inflate_state FAR *)strm->state;
1336 if ((state->wrap & 2) == 0) return Z_STREAM_ERROR;
1337
1338 /* save header structure */
1339 state->head = head;
1340 head->done = 0;
1341 return Z_OK;
1342}
1343
1344/*
1345 Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff. Return when found
1346 or when out of input. When called, *have is the number of pattern bytes
1347 found in order so far, in 0..3. On return *have is updated to the new
1348 state. If on return *have equals four, then the pattern was found and the
1349 return value is how many bytes were read including the last byte of the
1350 pattern. If *have is less than four, then the pattern has not been found
1351 yet and the return value is len. In the latter case, syncsearch() can be
1352 called again with more data and the *have state. *have is initialized to
1353 zero for the first call.
1354 */
1355local unsigned syncsearch(unsigned FAR *have, const unsigned char FAR *buf,
1356 unsigned len) {
1357 unsigned got;
1358 unsigned next;
1359
1360 got = *have;
1361 next = 0;
1362 while (next < len && got < 4) {
1363 if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
1364 got++;
1365 else if (buf[next])
1366 got = 0;
1367 else
1368 got = 4 - got;
1369 next++;
1370 }
1371 *have = got;
1372 return next;
1373}
1374
1375int ZEXPORT inflateSync(z_streamp strm) {
1376 unsigned len; /* number of bytes to look at or looked at */
1377 int flags; /* temporary to save header status */
1378 unsigned long in, out; /* temporary to save total_in and total_out */
1379 unsigned char buf[4]; /* to restore bit buffer to byte string */
1380 struct inflate_state FAR *state;
1381
1382 /* check parameters */
1383 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1384 state = (struct inflate_state FAR *)strm->state;
1385 if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;
1386
1387 /* if first time, start search in bit buffer */
1388 if (state->mode != SYNC) {
1389 state->mode = SYNC;
1390 state->hold <<= state->bits & 7;
1391 state->bits -= state->bits & 7;
1392 len = 0;
1393 while (state->bits >= 8) {
1394 buf[len++] = (unsigned char)(state->hold);
1395 state->hold >>= 8;
1396 state->bits -= 8;
1397 }
1398 state->have = 0;
1399 syncsearch(&(state->have), buf, len);
1400 }
1401
1402 /* search available input */
1403 len = syncsearch(&(state->have), strm->next_in, strm->avail_in);
1404 strm->avail_in -= len;
1405 strm->next_in += len;
1406 strm->total_in += len;
1407
1408 /* return no joy or set up to restart inflate() on a new block */
1409 if (state->have != 4) return Z_DATA_ERROR;
1410 if (state->flags == -1)
1411 state->wrap = 0; /* if no header yet, treat as raw */
1412 else
1413 state->wrap &= ~4; /* no point in computing a check value now */
1414 flags = state->flags;
1415 in = strm->total_in; out = strm->total_out;
1416 inflateReset(strm);
1417 strm->total_in = in; strm->total_out = out;
1418 state->flags = flags;
1419 state->mode = TYPE;
1420 return Z_OK;
1421}
1422
1423/*
1424 Returns true if inflate is currently at the end of a block generated by
1425 Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
1426 implementation to provide an additional safety check. PPP uses
1427 Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored
1428 block. When decompressing, PPP checks that at the end of input packet,
1429 inflate is waiting for these length bytes.
1430 */
1431int ZEXPORT inflateSyncPoint(z_streamp strm) {
1432 struct inflate_state FAR *state;
1433
1434 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1435 state = (struct inflate_state FAR *)strm->state;
1436 return state->mode == STORED && state->bits == 0;
1437}
1438
1439int ZEXPORT inflateCopy(z_streamp dest, z_streamp source) {
1440 struct inflate_state FAR *state;
1441 struct inflate_state FAR *copy;
1442 unsigned char FAR *window;
1443 unsigned wsize;
1444
1445 /* check input */
1446 if (inflateStateCheck(source) || dest == Z_NULL)
1447 return Z_STREAM_ERROR;
1448 state = (struct inflate_state FAR *)source->state;
1449
1450 /* allocate space */
1451 copy = (struct inflate_state FAR *)
1452 ZALLOC(source, 1, sizeof(struct inflate_state));
1453 if (copy == Z_NULL) return Z_MEM_ERROR;
1454 window = Z_NULL;
1455 if (state->window != Z_NULL) {
1456 window = (unsigned char FAR *)
1457 ZALLOC(source, 1U << state->wbits, sizeof(unsigned char));
1458 if (window == Z_NULL) {
1459 ZFREE(source, copy);
1460 return Z_MEM_ERROR;
1461 }
1462 }
1463
1464 /* copy state */
1465 zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
1466 zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state));
1467 copy->strm = dest;
1468 if (state->lencode >= state->codes &&
1469 state->lencode <= state->codes + ENOUGH - 1) {
1470 copy->lencode = copy->codes + (state->lencode - state->codes);
1471 copy->distcode = copy->codes + (state->distcode - state->codes);
1472 }
1473 copy->next = copy->codes + (state->next - state->codes);
1474 if (window != Z_NULL) {
1475 wsize = 1U << state->wbits;
1476 zmemcpy(window, state->window, wsize);
1477 }
1478 copy->window = window;
1479 dest->state = (struct internal_state FAR *)copy;
1480 return Z_OK;
1481}
1482
1483int ZEXPORT inflateUndermine(z_streamp strm, int subvert) {
1484 struct inflate_state FAR *state;
1485
1486 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1487 state = (struct inflate_state FAR *)strm->state;
1488#ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
1489 state->sane = !subvert;
1490 return Z_OK;
1491#else
1492 (void)subvert;
1493 state->sane = 1;
1494 return Z_DATA_ERROR;
1495#endif
1496}
1497
1498int ZEXPORT inflateValidate(z_streamp strm, int check) {
1499 struct inflate_state FAR *state;
1500
1501 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1502 state = (struct inflate_state FAR *)strm->state;
1503 if (check && state->wrap)
1504 state->wrap |= 4;
1505 else
1506 state->wrap &= ~4;
1507 return Z_OK;
1508}
1509
1510long ZEXPORT inflateMark(z_streamp strm) {
1511 struct inflate_state FAR *state;
1512
1513 if (inflateStateCheck(strm))
1514 return -(1L << 16);
1515 state = (struct inflate_state FAR *)strm->state;
1516 return (long)(((unsigned long)((long)state->back)) << 16) +
1517 (state->mode == COPY ? state->length :
1518 (state->mode == MATCH ? state->was - state->length : 0));
1519}
1520
1521unsigned long ZEXPORT inflateCodesUsed(z_streamp strm) {
1522 struct inflate_state FAR *state;
1523 if (inflateStateCheck(strm)) return (unsigned long)-1;
1524 state = (struct inflate_state FAR *)strm->state;
1525 return (unsigned long)(state->next - state->codes);
1526}
1527