1 /* inflate.c -- zlib decompression
2 * Copyright (C) 1995-2011 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
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
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
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
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
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
57 * 1.2.beta5 1 Jan 2003
58 * - Improved inflateBack() interface to allow the caller to provide initial
60 * - Fixed stored blocks bug in inflateBack()
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 *
69 * 1.2.beta7 27 Jan 2003
70 * - Changed many types to unsigned or unsigned short to avoid warnings
71 * - Added inflateCopy() function
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()
80 * The history for versions after 1.2.0 are in ChangeLog in zlib distribution.
94 /* function prototypes */
95 local void fixedtables OF((struct inflate_state FAR *state));
96 local int updatewindow OF((z_streamp strm, unsigned out));
98 void makefixed OF((void));
100 local unsigned syncsearch OF((unsigned FAR *have, unsigned char FAR *buf,
103 int ZEXPORT inflateResetKeep(strm)
106 struct inflate_state FAR *state;
108 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
109 state = (struct inflate_state FAR *)strm->state;
110 strm->total_in = strm->total_out = state->total = 0;
112 if (state->wrap) /* to support ill-conceived Java test suite */
113 strm->adler = state->wrap & 1;
117 state->dmax = 32768U;
118 state->head = Z_NULL;
121 state->lencode = state->distcode = state->next = state->codes;
124 Tracev((stderr, "inflate: reset\n"));
128 int ZEXPORT inflateReset(strm)
131 struct inflate_state FAR *state;
133 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
134 state = (struct inflate_state FAR *)strm->state;
138 return inflateResetKeep(strm);
141 int ZEXPORT inflateReset2(strm, windowBits)
146 struct inflate_state FAR *state;
149 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
150 state = (struct inflate_state FAR *)strm->state;
152 /* extract wrap request from windowBits parameter */
153 if (windowBits < 0) {
155 windowBits = -windowBits;
158 wrap = (windowBits >> 4) + 1;
165 /* set number of window bits, free window if different */
166 if (windowBits && (windowBits < 8 || windowBits > 15))
167 return Z_STREAM_ERROR;
168 if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
169 ZFREE(strm, state->window);
170 state->window = Z_NULL;
173 /* update state and reset the rest of it */
175 state->wbits = (unsigned)windowBits;
176 return inflateReset(strm);
179 int ZEXPORT inflateInit2_(strm, windowBits, version, stream_size)
186 struct inflate_state FAR *state;
188 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
189 stream_size != (int)(sizeof(z_stream)))
190 return Z_VERSION_ERROR;
191 if (strm == Z_NULL) return Z_STREAM_ERROR;
192 strm->msg = Z_NULL; /* in case we return an error */
193 if (strm->zalloc == (alloc_func)0) {
195 return Z_STREAM_ERROR;
197 strm->zalloc = zcalloc;
198 strm->opaque = (voidpf)0;
201 if (strm->zfree == (free_func)0)
203 return Z_STREAM_ERROR;
205 strm->zfree = zcfree;
207 state = (struct inflate_state FAR *)
208 ZALLOC(strm, 1, sizeof(struct inflate_state));
209 if (state == Z_NULL) return Z_MEM_ERROR;
210 Tracev((stderr, "inflate: allocated\n"));
211 strm->state = (struct internal_state FAR *)state;
212 state->window = Z_NULL;
213 ret = inflateReset2(strm, windowBits);
216 strm->state = Z_NULL;
221 int ZEXPORT inflateInit_(strm, version, stream_size)
226 return inflateInit2_(strm, DEF_WBITS, version, stream_size);
229 int ZEXPORT inflatePrime(strm, bits, value)
234 struct inflate_state FAR *state;
236 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
237 state = (struct inflate_state FAR *)strm->state;
243 if (bits > 16 || state->bits + bits > 32) return Z_STREAM_ERROR;
244 value &= (1L << bits) - 1;
245 state->hold += value << state->bits;
251 Return state with length and distance decoding tables and index sizes set to
252 fixed code decoding. Normally this returns fixed tables from inffixed.h.
253 If BUILDFIXED is defined, then instead this routine builds the tables the
254 first time it's called, and returns those tables the first time and
255 thereafter. This reduces the size of the code by about 2K bytes, in
256 exchange for a little execution time. However, BUILDFIXED should not be
257 used for threaded applications, since the rewriting of the tables and virgin
258 may not be thread-safe.
260 local void fixedtables(state)
261 struct inflate_state FAR *state;
264 static int virgin = 1;
265 static code *lenfix, *distfix;
266 static code fixed[544];
268 /* build fixed huffman tables if first call (may not be thread safe) */
273 /* literal/length table */
275 while (sym < 144) state->lens[sym++] = 8;
276 while (sym < 256) state->lens[sym++] = 9;
277 while (sym < 280) state->lens[sym++] = 7;
278 while (sym < 288) state->lens[sym++] = 8;
282 inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
286 while (sym < 32) state->lens[sym++] = 5;
289 inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
291 /* do this just once */
294 #else /* !BUILDFIXED */
295 # include "inffixed.h"
296 #endif /* BUILDFIXED */
297 state->lencode = lenfix;
299 state->distcode = distfix;
307 Write out the inffixed.h that is #include'd above. Defining MAKEFIXED also
308 defines BUILDFIXED, so the tables are built on the fly. makefixed() writes
309 those tables to stdout, which would be piped to inffixed.h. A small program
310 can simply call makefixed to do this:
312 void makefixed(void);
320 Then that can be linked with zlib built with MAKEFIXED defined and run:
327 struct inflate_state state;
330 puts(" /* inffixed.h -- table for decoding fixed codes");
331 puts(" * Generated automatically by makefixed().");
334 puts(" /* WARNING: this file should *not* be used by applications.");
335 puts(" It is part of the implementation of this library and is");
336 puts(" subject to change. Applications should only use zlib.h.");
340 printf(" static const code lenfix[%u] = {", size);
343 if ((low % 7) == 0) printf("\n ");
344 printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,
345 state.lencode[low].bits, state.lencode[low].val);
346 if (++low == size) break;
351 printf("\n static const code distfix[%u] = {", size);
354 if ((low % 6) == 0) printf("\n ");
355 printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits,
356 state.distcode[low].val);
357 if (++low == size) break;
362 #endif /* MAKEFIXED */
365 Update the window with the last wsize (normally 32K) bytes written before
366 returning. If window does not exist yet, create it. This is only called
367 when a window is already in use, or when output has been written during this
368 inflate call, but the end of the deflate stream has not been reached yet.
369 It is also called to create a window for dictionary data when a dictionary
372 Providing output buffers larger than 32K to inflate() should provide a speed
373 advantage, since only the last 32K of output is copied to the sliding window
374 upon return from inflate(), and since all distances after the first 32K of
375 output will fall in the output data, making match copies simpler and faster.
376 The advantage may be dependent on the size of the processor's data caches.
378 local int updatewindow(strm, out)
382 struct inflate_state FAR *state;
385 state = (struct inflate_state FAR *)strm->state;
387 /* if it hasn't been done already, allocate space for the window */
388 if (state->window == Z_NULL) {
389 state->window = (unsigned char FAR *)
390 ZALLOC(strm, 1U << state->wbits,
391 sizeof(unsigned char));
392 if (state->window == Z_NULL) return 1;
395 /* if window not in use yet, initialize */
396 if (state->wsize == 0) {
397 state->wsize = 1U << state->wbits;
402 /* copy state->wsize or less output bytes into the circular window */
403 copy = out - strm->avail_out;
404 if (copy >= state->wsize) {
405 zmemcpy(state->window, strm->next_out - state->wsize, state->wsize);
407 state->whave = state->wsize;
410 dist = state->wsize - state->wnext;
411 if (dist > copy) dist = copy;
412 zmemcpy(state->window + state->wnext, strm->next_out - copy, dist);
415 zmemcpy(state->window, strm->next_out - copy, copy);
417 state->whave = state->wsize;
420 state->wnext += dist;
421 if (state->wnext == state->wsize) state->wnext = 0;
422 if (state->whave < state->wsize) state->whave += dist;
428 /* Macros for inflate(): */
430 /* check function to use adler32() for zlib or crc32() for gzip */
432 # define UPDATE(check, buf, len) \
433 (state->flags ? crc32(check, buf, len) : adler32(check, buf, len))
435 # define UPDATE(check, buf, len) adler32(check, buf, len)
438 /* check macros for header crc */
440 # define CRC2(check, word) \
442 hbuf[0] = (unsigned char)(word); \
443 hbuf[1] = (unsigned char)((word) >> 8); \
444 check = crc32(check, hbuf, 2); \
447 # define CRC4(check, word) \
449 hbuf[0] = (unsigned char)(word); \
450 hbuf[1] = (unsigned char)((word) >> 8); \
451 hbuf[2] = (unsigned char)((word) >> 16); \
452 hbuf[3] = (unsigned char)((word) >> 24); \
453 check = crc32(check, hbuf, 4); \
457 /* Load registers with state in inflate() for speed */
460 put = strm->next_out; \
461 left = strm->avail_out; \
462 next = strm->next_in; \
463 have = strm->avail_in; \
464 hold = state->hold; \
465 bits = state->bits; \
468 /* Restore state from registers in inflate() */
471 strm->next_out = put; \
472 strm->avail_out = left; \
473 strm->next_in = next; \
474 strm->avail_in = have; \
475 state->hold = hold; \
476 state->bits = bits; \
479 /* Clear the input bit accumulator */
486 /* Get a byte of input into the bit accumulator, or return from inflate()
487 if there is no input available. */
490 if (have == 0) goto inf_leave; \
492 hold += (unsigned long)(*next++) << bits; \
496 /* Assure that there are at least n bits in the bit accumulator. If there is
497 not enough available input to do that, then return from inflate(). */
498 #define NEEDBITS(n) \
500 while (bits < (unsigned)(n)) \
504 /* Return the low n bits of the bit accumulator (n < 16) */
506 ((unsigned)hold & ((1U << (n)) - 1))
508 /* Remove n bits from the bit accumulator */
509 #define DROPBITS(n) \
512 bits -= (unsigned)(n); \
515 /* Remove zero to seven bits as needed to go to a byte boundary */
522 /* Reverse the bytes in a 32-bit value */
524 ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \
525 (((q) & 0xff00) << 8) + (((q) & 0xff) << 24))
528 inflate() uses a state machine to process as much input data and generate as
529 much output data as possible before returning. The state machine is
530 structured roughly as follows:
532 for (;;) switch (state) {
535 if (not enough input data or output space to make progress)
537 ... make progress ...
543 so when inflate() is called again, the same case is attempted again, and
544 if the appropriate resources are provided, the machine proceeds to the
545 next state. The NEEDBITS() macro is usually the way the state evaluates
546 whether it can proceed or should return. NEEDBITS() does the return if
547 the requested bits are not available. The typical use of the BITS macros
551 ... do something with BITS(n) ...
554 where NEEDBITS(n) either returns from inflate() if there isn't enough
555 input left to load n bits into the accumulator, or it continues. BITS(n)
556 gives the low n bits in the accumulator. When done, DROPBITS(n) drops
557 the low n bits off the accumulator. INITBITS() clears the accumulator
558 and sets the number of available bits to zero. BYTEBITS() discards just
559 enough bits to put the accumulator on a byte boundary. After BYTEBITS()
560 and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
562 NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
563 if there is no input available. The decoding of variable length codes uses
564 PULLBYTE() directly in order to pull just enough bytes to decode the next
567 Some states loop until they get enough input, making sure that enough
568 state information is maintained to continue the loop where it left off
569 if NEEDBITS() returns in the loop. For example, want, need, and keep
570 would all have to actually be part of the saved state in case NEEDBITS()
574 while (want < need) {
576 keep[want++] = BITS(n);
582 As shown above, if the next state is also the next case, then the break
585 A state may also return if there is not enough output space available to
586 complete that state. Those states are copying stored data, writing a
587 literal byte, and copying a matching string.
589 When returning, a "goto inf_leave" is used to update the total counters,
590 update the check value, and determine whether any progress has been made
591 during that inflate() call in order to return the proper return code.
592 Progress is defined as a change in either strm->avail_in or strm->avail_out.
593 When there is a window, goto inf_leave will update the window with the last
594 output written. If a goto inf_leave occurs in the middle of decompression
595 and there is no window currently, goto inf_leave will create one and copy
596 output to the window for the next call of inflate().
598 In this implementation, the flush parameter of inflate() only affects the
599 return code (per zlib.h). inflate() always writes as much as possible to
600 strm->next_out, given the space available and the provided input--the effect
601 documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers
602 the allocation of and copying into a sliding window until necessary, which
603 provides the effect documented in zlib.h for Z_FINISH when the entire input
604 stream available. So the only thing the flush parameter actually does is:
605 when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it
606 will return Z_BUF_ERROR if it has not reached the end of the stream.
609 int ZEXPORT inflate(strm, flush)
613 struct inflate_state FAR *state;
614 unsigned char FAR *next; /* next input */
615 unsigned char FAR *put; /* next output */
616 unsigned have, left; /* available input and output */
617 unsigned long hold; /* bit buffer */
618 unsigned bits; /* bits in bit buffer */
619 unsigned in, out; /* save starting available input and output */
620 unsigned copy; /* number of stored or match bytes to copy */
621 unsigned char FAR *from; /* where to copy match bytes from */
622 code here; /* current decoding table entry */
623 code last; /* parent table entry */
624 unsigned len; /* length to copy for repeats, bits to drop */
625 int ret; /* return code */
627 unsigned char hbuf[4]; /* buffer for gzip header crc calculation */
629 static const unsigned short order[19] = /* permutation of code lengths */
630 {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
632 if (strm == Z_NULL || strm->state == Z_NULL || strm->next_out == Z_NULL ||
633 (strm->next_in == Z_NULL && strm->avail_in != 0))
634 return Z_STREAM_ERROR;
636 state = (struct inflate_state FAR *)strm->state;
637 if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */
643 switch (state->mode) {
645 if (state->wrap == 0) {
646 state->mode = TYPEDO;
651 if ((state->wrap & 2) && hold == 0x8b1f) { /* gzip header */
652 state->check = crc32(0L, Z_NULL, 0);
653 CRC2(state->check, hold);
658 state->flags = 0; /* expect zlib header */
659 if (state->head != Z_NULL)
660 state->head->done = -1;
661 if (!(state->wrap & 1) || /* check if zlib header allowed */
665 ((BITS(8) << 8) + (hold >> 8)) % 31) {
666 strm->msg = (char *)"incorrect header check";
670 if (BITS(4) != Z_DEFLATED) {
671 strm->msg = (char *)"unknown compression method";
677 if (state->wbits == 0)
679 else if (len > state->wbits) {
680 strm->msg = (char *)"invalid window size";
684 state->dmax = 1U << len;
685 Tracev((stderr, "inflate: zlib header ok\n"));
686 strm->adler = state->check = adler32(0L, Z_NULL, 0);
687 state->mode = hold & 0x200 ? DICTID : TYPE;
693 state->flags = (int)(hold);
694 if ((state->flags & 0xff) != Z_DEFLATED) {
695 strm->msg = (char *)"unknown compression method";
699 if (state->flags & 0xe000) {
700 strm->msg = (char *)"unknown header flags set";
704 if (state->head != Z_NULL)
705 state->head->text = (int)((hold >> 8) & 1);
706 if (state->flags & 0x0200) CRC2(state->check, hold);
711 if (state->head != Z_NULL)
712 state->head->time = hold;
713 if (state->flags & 0x0200) CRC4(state->check, hold);
718 if (state->head != Z_NULL) {
719 state->head->xflags = (int)(hold & 0xff);
720 state->head->os = (int)(hold >> 8);
722 if (state->flags & 0x0200) CRC2(state->check, hold);
726 if (state->flags & 0x0400) {
728 state->length = (unsigned)(hold);
729 if (state->head != Z_NULL)
730 state->head->extra_len = (unsigned)hold;
731 if (state->flags & 0x0200) CRC2(state->check, hold);
734 else if (state->head != Z_NULL)
735 state->head->extra = Z_NULL;
738 if (state->flags & 0x0400) {
739 copy = state->length;
740 if (copy > have) copy = have;
742 if (state->head != Z_NULL &&
743 state->head->extra != Z_NULL) {
744 len = state->head->extra_len - state->length;
745 zmemcpy(state->head->extra + len, next,
746 len + copy > state->head->extra_max ?
747 state->head->extra_max - len : copy);
749 if (state->flags & 0x0200)
750 state->check = crc32(state->check, next, copy);
753 state->length -= copy;
755 if (state->length) goto inf_leave;
760 if (state->flags & 0x0800) {
761 if (have == 0) goto inf_leave;
764 len = (unsigned)(next[copy++]);
765 if (state->head != Z_NULL &&
766 state->head->name != Z_NULL &&
767 state->length < state->head->name_max)
768 state->head->name[state->length++] = len;
769 } while (len && copy < have);
770 if (state->flags & 0x0200)
771 state->check = crc32(state->check, next, copy);
774 if (len) goto inf_leave;
776 else if (state->head != Z_NULL)
777 state->head->name = Z_NULL;
779 state->mode = COMMENT;
781 if (state->flags & 0x1000) {
782 if (have == 0) goto inf_leave;
785 len = (unsigned)(next[copy++]);
786 if (state->head != Z_NULL &&
787 state->head->comment != Z_NULL &&
788 state->length < state->head->comm_max)
789 state->head->comment[state->length++] = len;
790 } while (len && copy < have);
791 if (state->flags & 0x0200)
792 state->check = crc32(state->check, next, copy);
795 if (len) goto inf_leave;
797 else if (state->head != Z_NULL)
798 state->head->comment = Z_NULL;
801 if (state->flags & 0x0200) {
803 if (hold != (state->check & 0xffff)) {
804 strm->msg = (char *)"header crc mismatch";
810 if (state->head != Z_NULL) {
811 state->head->hcrc = (int)((state->flags >> 9) & 1);
812 state->head->done = 1;
814 strm->adler = state->check = crc32(0L, Z_NULL, 0);
820 strm->adler = state->check = REVERSE(hold);
824 if (state->havedict == 0) {
828 strm->adler = state->check = adler32(0L, Z_NULL, 0);
831 if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
839 state->last = BITS(1);
842 case 0: /* stored block */
843 Tracev((stderr, "inflate: stored block%s\n",
844 state->last ? " (last)" : ""));
845 state->mode = STORED;
847 case 1: /* fixed block */
849 Tracev((stderr, "inflate: fixed codes block%s\n",
850 state->last ? " (last)" : ""));
851 state->mode = LEN_; /* decode codes */
852 if (flush == Z_TREES) {
857 case 2: /* dynamic block */
858 Tracev((stderr, "inflate: dynamic codes block%s\n",
859 state->last ? " (last)" : ""));
863 strm->msg = (char *)"invalid block type";
869 BYTEBITS(); /* go to byte boundary */
871 if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
872 strm->msg = (char *)"invalid stored block lengths";
876 state->length = (unsigned)hold & 0xffff;
877 Tracev((stderr, "inflate: stored length %u\n",
881 if (flush == Z_TREES) goto inf_leave;
885 copy = state->length;
887 if (copy > have) copy = have;
888 if (copy > left) copy = left;
889 if (copy == 0) goto inf_leave;
890 zmemcpy(put, next, copy);
895 state->length -= copy;
898 Tracev((stderr, "inflate: stored end\n"));
903 state->nlen = BITS(5) + 257;
905 state->ndist = BITS(5) + 1;
907 state->ncode = BITS(4) + 4;
909 #ifndef PKZIP_BUG_WORKAROUND
910 if (state->nlen > 286 || state->ndist > 30) {
911 strm->msg = (char *)"too many length or distance symbols";
916 Tracev((stderr, "inflate: table sizes ok\n"));
918 state->mode = LENLENS;
920 while (state->have < state->ncode) {
922 state->lens[order[state->have++]] = (unsigned short)BITS(3);
925 while (state->have < 19)
926 state->lens[order[state->have++]] = 0;
927 state->next = state->codes;
928 state->lencode = (code const FAR *)(state->next);
930 ret = inflate_table(CODES, state->lens, 19, &(state->next),
931 &(state->lenbits), state->work);
933 strm->msg = (char *)"invalid code lengths set";
937 Tracev((stderr, "inflate: code lengths ok\n"));
939 state->mode = CODELENS;
941 while (state->have < state->nlen + state->ndist) {
943 here = state->lencode[BITS(state->lenbits)];
944 if ((unsigned)(here.bits) <= bits) break;
949 state->lens[state->have++] = here.val;
952 if (here.val == 16) {
953 NEEDBITS(here.bits + 2);
955 if (state->have == 0) {
956 strm->msg = (char *)"invalid bit length repeat";
960 len = state->lens[state->have - 1];
964 else if (here.val == 17) {
965 NEEDBITS(here.bits + 3);
972 NEEDBITS(here.bits + 7);
978 if (state->have + copy > state->nlen + state->ndist) {
979 strm->msg = (char *)"invalid bit length repeat";
984 state->lens[state->have++] = (unsigned short)len;
988 /* handle error breaks in while */
989 if (state->mode == BAD) break;
991 /* check for end-of-block code (better have one) */
992 if (state->lens[256] == 0) {
993 strm->msg = (char *)"invalid code -- missing end-of-block";
998 /* build code tables -- note: do not change the lenbits or distbits
999 values here (9 and 6) without reading the comments in inftrees.h
1000 concerning the ENOUGH constants, which depend on those values */
1001 state->next = state->codes;
1002 state->lencode = (code const FAR *)(state->next);
1004 ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
1005 &(state->lenbits), state->work);
1007 strm->msg = (char *)"invalid literal/lengths set";
1011 state->distcode = (code const FAR *)(state->next);
1012 state->distbits = 6;
1013 ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
1014 &(state->next), &(state->distbits), state->work);
1016 strm->msg = (char *)"invalid distances set";
1020 Tracev((stderr, "inflate: codes ok\n"));
1022 if (flush == Z_TREES) goto inf_leave;
1026 if (have >= 6 && left >= 258) {
1028 inflate_fast(strm, out);
1030 if (state->mode == TYPE)
1036 here = state->lencode[BITS(state->lenbits)];
1037 if ((unsigned)(here.bits) <= bits) break;
1040 if (here.op && (here.op & 0xf0) == 0) {
1043 here = state->lencode[last.val +
1044 (BITS(last.bits + last.op) >> last.bits)];
1045 if ((unsigned)(last.bits + here.bits) <= bits) break;
1048 DROPBITS(last.bits);
1049 state->back += last.bits;
1051 DROPBITS(here.bits);
1052 state->back += here.bits;
1053 state->length = (unsigned)here.val;
1054 if ((int)(here.op) == 0) {
1055 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
1056 "inflate: literal '%c'\n" :
1057 "inflate: literal 0x%02x\n", here.val));
1062 Tracevv((stderr, "inflate: end of block\n"));
1068 strm->msg = (char *)"invalid literal/length code";
1072 state->extra = (unsigned)(here.op) & 15;
1073 state->mode = LENEXT;
1076 NEEDBITS(state->extra);
1077 state->length += BITS(state->extra);
1078 DROPBITS(state->extra);
1079 state->back += state->extra;
1081 Tracevv((stderr, "inflate: length %u\n", state->length));
1082 state->was = state->length;
1086 here = state->distcode[BITS(state->distbits)];
1087 if ((unsigned)(here.bits) <= bits) break;
1090 if ((here.op & 0xf0) == 0) {
1093 here = state->distcode[last.val +
1094 (BITS(last.bits + last.op) >> last.bits)];
1095 if ((unsigned)(last.bits + here.bits) <= bits) break;
1098 DROPBITS(last.bits);
1099 state->back += last.bits;
1101 DROPBITS(here.bits);
1102 state->back += here.bits;
1104 strm->msg = (char *)"invalid distance code";
1108 state->offset = (unsigned)here.val;
1109 state->extra = (unsigned)(here.op) & 15;
1110 state->mode = DISTEXT;
1113 NEEDBITS(state->extra);
1114 state->offset += BITS(state->extra);
1115 DROPBITS(state->extra);
1116 state->back += state->extra;
1118 #ifdef INFLATE_STRICT
1119 if (state->offset > state->dmax) {
1120 strm->msg = (char *)"invalid distance too far back";
1125 Tracevv((stderr, "inflate: distance %u\n", state->offset));
1126 state->mode = MATCH;
1128 if (left == 0) goto inf_leave;
1130 if (state->offset > copy) { /* copy from window */
1131 copy = state->offset - copy;
1132 if (copy > state->whave) {
1134 strm->msg = (char *)"invalid distance too far back";
1138 #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
1139 Trace((stderr, "inflate.c too far\n"));
1140 copy -= state->whave;
1141 if (copy > state->length) copy = state->length;
1142 if (copy > left) copy = left;
1144 state->length -= copy;
1148 if (state->length == 0) state->mode = LEN;
1152 if (copy > state->wnext) {
1153 copy -= state->wnext;
1154 from = state->window + (state->wsize - copy);
1157 from = state->window + (state->wnext - copy);
1158 if (copy > state->length) copy = state->length;
1160 else { /* copy from output */
1161 from = put - state->offset;
1162 copy = state->length;
1164 if (copy > left) copy = left;
1166 state->length -= copy;
1170 if (state->length == 0) state->mode = LEN;
1173 if (left == 0) goto inf_leave;
1174 *put++ = (unsigned char)(state->length);
1182 strm->total_out += out;
1183 state->total += out;
1185 strm->adler = state->check =
1186 UPDATE(state->check, put - out, out);
1190 state->flags ? hold :
1192 REVERSE(hold)) != state->check) {
1193 strm->msg = (char *)"incorrect data check";
1198 Tracev((stderr, "inflate: check matches trailer\n"));
1201 state->mode = LENGTH;
1203 if (state->wrap && state->flags) {
1205 if (hold != (state->total & 0xffffffffUL)) {
1206 strm->msg = (char *)"incorrect length check";
1211 Tracev((stderr, "inflate: length matches trailer\n"));
1225 return Z_STREAM_ERROR;
1229 Return from inflate(), updating the total counts and the check value.
1230 If there was no progress during the inflate() call, return a buffer
1231 error. Call updatewindow() to create and/or update the window state.
1232 Note: a memory error from inflate() is non-recoverable.
1236 if (state->wsize || (out != strm->avail_out && state->mode < BAD &&
1237 (state->mode < CHECK || flush != Z_FINISH)))
1238 if (updatewindow(strm, out)) {
1242 in -= strm->avail_in;
1243 out -= strm->avail_out;
1244 strm->total_in += in;
1245 strm->total_out += out;
1246 state->total += out;
1247 if (state->wrap && out)
1248 strm->adler = state->check =
1249 UPDATE(state->check, strm->next_out - out, out);
1250 strm->data_type = state->bits + (state->last ? 64 : 0) +
1251 (state->mode == TYPE ? 128 : 0) +
1252 (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
1253 if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
1258 int ZEXPORT inflateEnd(strm)
1261 struct inflate_state FAR *state;
1262 if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
1263 return Z_STREAM_ERROR;
1264 state = (struct inflate_state FAR *)strm->state;
1265 if (state->window != Z_NULL) ZFREE(strm, state->window);
1266 ZFREE(strm, strm->state);
1267 strm->state = Z_NULL;
1268 Tracev((stderr, "inflate: end\n"));
1272 int ZEXPORT inflateSetDictionary(strm, dictionary, dictLength)
1274 const Bytef *dictionary;
1277 struct inflate_state FAR *state;
1279 unsigned char *next;
1284 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1285 state = (struct inflate_state FAR *)strm->state;
1286 if (state->wrap != 0 && state->mode != DICT)
1287 return Z_STREAM_ERROR;
1289 /* check for correct dictionary id */
1290 if (state->mode == DICT) {
1291 id = adler32(0L, Z_NULL, 0);
1292 id = adler32(id, dictionary, dictLength);
1293 if (id != state->check)
1294 return Z_DATA_ERROR;
1297 /* copy dictionary to window using updatewindow(), which will amend the
1298 existing dictionary if appropriate */
1299 next = strm->next_out;
1300 avail = strm->avail_out;
1301 strm->next_out = (Bytef *)dictionary + dictLength;
1302 strm->avail_out = 0;
1303 ret = updatewindow(strm, dictLength);
1304 strm->avail_out = avail;
1305 strm->next_out = next;
1310 state->havedict = 1;
1311 Tracev((stderr, "inflate: dictionary set\n"));
1315 int ZEXPORT inflateGetHeader(strm, head)
1319 struct inflate_state FAR *state;
1322 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1323 state = (struct inflate_state FAR *)strm->state;
1324 if ((state->wrap & 2) == 0) return Z_STREAM_ERROR;
1326 /* save header structure */
1333 Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff. Return when found
1334 or when out of input. When called, *have is the number of pattern bytes
1335 found in order so far, in 0..3. On return *have is updated to the new
1336 state. If on return *have equals four, then the pattern was found and the
1337 return value is how many bytes were read including the last byte of the
1338 pattern. If *have is less than four, then the pattern has not been found
1339 yet and the return value is len. In the latter case, syncsearch() can be
1340 called again with more data and the *have state. *have is initialized to
1341 zero for the first call.
1343 local unsigned syncsearch(have, buf, len)
1345 unsigned char FAR *buf;
1353 while (next < len && got < 4) {
1354 if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
1366 int ZEXPORT inflateSync(strm)
1369 unsigned len; /* number of bytes to look at or looked at */
1370 unsigned long in, out; /* temporary to save total_in and total_out */
1371 unsigned char buf[4]; /* to restore bit buffer to byte string */
1372 struct inflate_state FAR *state;
1374 /* check parameters */
1375 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1376 state = (struct inflate_state FAR *)strm->state;
1377 if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;
1379 /* if first time, start search in bit buffer */
1380 if (state->mode != SYNC) {
1382 state->hold <<= state->bits & 7;
1383 state->bits -= state->bits & 7;
1385 while (state->bits >= 8) {
1386 buf[len++] = (unsigned char)(state->hold);
1391 syncsearch(&(state->have), buf, len);
1394 /* search available input */
1395 len = syncsearch(&(state->have), strm->next_in, strm->avail_in);
1396 strm->avail_in -= len;
1397 strm->next_in += len;
1398 strm->total_in += len;
1400 /* return no joy or set up to restart inflate() on a new block */
1401 if (state->have != 4) return Z_DATA_ERROR;
1402 in = strm->total_in; out = strm->total_out;
1404 strm->total_in = in; strm->total_out = out;
1410 Returns true if inflate is currently at the end of a block generated by
1411 Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
1412 implementation to provide an additional safety check. PPP uses
1413 Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored
1414 block. When decompressing, PPP checks that at the end of input packet,
1415 inflate is waiting for these length bytes.
1417 int ZEXPORT inflateSyncPoint(strm)
1420 struct inflate_state FAR *state;
1422 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1423 state = (struct inflate_state FAR *)strm->state;
1424 return state->mode == STORED && state->bits == 0;
1427 int ZEXPORT inflateCopy(dest, source)
1431 struct inflate_state FAR *state;
1432 struct inflate_state FAR *copy;
1433 unsigned char FAR *window;
1437 if (dest == Z_NULL || source == Z_NULL || source->state == Z_NULL ||
1438 source->zalloc == (alloc_func)0 || source->zfree == (free_func)0)
1439 return Z_STREAM_ERROR;
1440 state = (struct inflate_state FAR *)source->state;
1442 /* allocate space */
1443 copy = (struct inflate_state FAR *)
1444 ZALLOC(source, 1, sizeof(struct inflate_state));
1445 if (copy == Z_NULL) return Z_MEM_ERROR;
1447 if (state->window != Z_NULL) {
1448 window = (unsigned char FAR *)
1449 ZALLOC(source, 1U << state->wbits, sizeof(unsigned char));
1450 if (window == Z_NULL) {
1451 ZFREE(source, copy);
1457 zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
1458 zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state));
1459 if (state->lencode >= state->codes &&
1460 state->lencode <= state->codes + ENOUGH - 1) {
1461 copy->lencode = copy->codes + (state->lencode - state->codes);
1462 copy->distcode = copy->codes + (state->distcode - state->codes);
1464 copy->next = copy->codes + (state->next - state->codes);
1465 if (window != Z_NULL) {
1466 wsize = 1U << state->wbits;
1467 zmemcpy(window, state->window, wsize);
1469 copy->window = window;
1470 dest->state = (struct internal_state FAR *)copy;
1474 int ZEXPORT inflateUndermine(strm, subvert)
1478 struct inflate_state FAR *state;
1480 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1481 state = (struct inflate_state FAR *)strm->state;
1482 state->sane = !subvert;
1483 #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
1487 return Z_DATA_ERROR;
1491 long ZEXPORT inflateMark(strm)
1494 struct inflate_state FAR *state;
1496 if (strm == Z_NULL || strm->state == Z_NULL) return -1L << 16;
1497 state = (struct inflate_state FAR *)strm->state;
1498 return ((long)(state->back) << 16) +
1499 (state->mode == COPY ? state->length :
1500 (state->mode == MATCH ? state->was - state->length : 0));