1 /* inflate.c -- zlib decompression
2 * Copyright (C) 1995-2016 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 int inflateStateCheck OF((z_streamp strm));
96 local void fixedtables OF((struct inflate_state FAR *state));
97 local int updatewindow OF((z_streamp strm, const unsigned char FAR *end,
100 void makefixed OF((void));
102 local unsigned syncsearch OF((unsigned FAR *have, const unsigned char FAR *buf,
105 local int inflateStateCheck(strm)
108 struct inflate_state FAR *state;
109 if (strm == Z_NULL ||
110 strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
112 state = (struct inflate_state FAR *)strm->state;
113 if (state == Z_NULL || state->strm != strm ||
114 state->mode < HEAD || state->mode > SYNC)
119 int ZEXPORT inflateResetKeep(strm)
122 struct inflate_state FAR *state;
124 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
125 state = (struct inflate_state FAR *)strm->state;
126 strm->total_in = strm->total_out = state->total = 0;
128 if (state->wrap) /* to support ill-conceived Java test suite */
129 strm->adler = state->wrap & 1;
134 state->dmax = 32768U;
135 state->head = Z_NULL;
138 state->lencode = state->distcode = state->next = state->codes;
141 Tracev((stderr, "inflate: reset\n"));
145 int ZEXPORT inflateReset(strm)
148 struct inflate_state FAR *state;
150 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
151 state = (struct inflate_state FAR *)strm->state;
155 return inflateResetKeep(strm);
158 int ZEXPORT inflateReset2(strm, windowBits)
163 struct inflate_state FAR *state;
166 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
167 state = (struct inflate_state FAR *)strm->state;
169 /* extract wrap request from windowBits parameter */
170 if (windowBits < 0) {
172 windowBits = -windowBits;
175 wrap = (windowBits >> 4) + 5;
182 /* set number of window bits, free window if different */
183 if (windowBits && (windowBits < 8 || windowBits > 15))
184 return Z_STREAM_ERROR;
185 if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
186 ZFREE(strm, state->window);
187 state->window = Z_NULL;
190 /* update state and reset the rest of it */
192 state->wbits = (unsigned)windowBits;
193 return inflateReset(strm);
196 int ZEXPORT inflateInit2_(strm, windowBits, version, stream_size)
203 struct inflate_state FAR *state;
205 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
206 stream_size != (int)(sizeof(z_stream)))
207 return Z_VERSION_ERROR;
208 if (strm == Z_NULL) return Z_STREAM_ERROR;
209 strm->msg = Z_NULL; /* in case we return an error */
210 if (strm->zalloc == (alloc_func)0) {
212 return Z_STREAM_ERROR;
214 strm->zalloc = zcalloc;
215 strm->opaque = (voidpf)0;
218 if (strm->zfree == (free_func)0)
220 return Z_STREAM_ERROR;
222 strm->zfree = zcfree;
224 state = (struct inflate_state FAR *)
225 ZALLOC(strm, 1, sizeof(struct inflate_state));
226 if (state == Z_NULL) return Z_MEM_ERROR;
227 Tracev((stderr, "inflate: allocated\n"));
228 strm->state = (struct internal_state FAR *)state;
230 state->window = Z_NULL;
231 state->mode = HEAD; /* to pass state test in inflateReset2() */
232 ret = inflateReset2(strm, windowBits);
235 strm->state = Z_NULL;
240 int ZEXPORT inflateInit_(strm, version, stream_size)
245 return inflateInit2_(strm, DEF_WBITS, version, stream_size);
248 int ZEXPORT inflatePrime(strm, bits, value)
253 struct inflate_state FAR *state;
255 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
256 state = (struct inflate_state FAR *)strm->state;
262 if (bits > 16 || state->bits + (uInt)bits > 32) return Z_STREAM_ERROR;
263 value &= (1L << bits) - 1;
264 state->hold += (unsigned)value << state->bits;
265 state->bits += (uInt)bits;
270 Return state with length and distance decoding tables and index sizes set to
271 fixed code decoding. Normally this returns fixed tables from inffixed.h.
272 If BUILDFIXED is defined, then instead this routine builds the tables the
273 first time it's called, and returns those tables the first time and
274 thereafter. This reduces the size of the code by about 2K bytes, in
275 exchange for a little execution time. However, BUILDFIXED should not be
276 used for threaded applications, since the rewriting of the tables and virgin
277 may not be thread-safe.
279 local void fixedtables(state)
280 struct inflate_state FAR *state;
283 static int virgin = 1;
284 static code *lenfix, *distfix;
285 static code fixed[544];
287 /* build fixed huffman tables if first call (may not be thread safe) */
292 /* literal/length table */
294 while (sym < 144) state->lens[sym++] = 8;
295 while (sym < 256) state->lens[sym++] = 9;
296 while (sym < 280) state->lens[sym++] = 7;
297 while (sym < 288) state->lens[sym++] = 8;
301 inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
305 while (sym < 32) state->lens[sym++] = 5;
308 inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
310 /* do this just once */
313 #else /* !BUILDFIXED */
314 # include "inffixed.h"
315 #endif /* BUILDFIXED */
316 state->lencode = lenfix;
318 state->distcode = distfix;
326 Write out the inffixed.h that is #include'd above. Defining MAKEFIXED also
327 defines BUILDFIXED, so the tables are built on the fly. makefixed() writes
328 those tables to stdout, which would be piped to inffixed.h. A small program
329 can simply call makefixed to do this:
331 void makefixed(void);
339 Then that can be linked with zlib built with MAKEFIXED defined and run:
346 struct inflate_state state;
349 puts(" /* inffixed.h -- table for decoding fixed codes");
350 puts(" * Generated automatically by makefixed().");
353 puts(" /* WARNING: this file should *not* be used by applications.");
354 puts(" It is part of the implementation of this library and is");
355 puts(" subject to change. Applications should only use zlib.h.");
359 printf(" static const code lenfix[%u] = {", size);
362 if ((low % 7) == 0) printf("\n ");
363 printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,
364 state.lencode[low].bits, state.lencode[low].val);
365 if (++low == size) break;
370 printf("\n static const code distfix[%u] = {", size);
373 if ((low % 6) == 0) printf("\n ");
374 printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits,
375 state.distcode[low].val);
376 if (++low == size) break;
381 #endif /* MAKEFIXED */
384 Update the window with the last wsize (normally 32K) bytes written before
385 returning. If window does not exist yet, create it. This is only called
386 when a window is already in use, or when output has been written during this
387 inflate call, but the end of the deflate stream has not been reached yet.
388 It is also called to create a window for dictionary data when a dictionary
391 Providing output buffers larger than 32K to inflate() should provide a speed
392 advantage, since only the last 32K of output is copied to the sliding window
393 upon return from inflate(), and since all distances after the first 32K of
394 output will fall in the output data, making match copies simpler and faster.
395 The advantage may be dependent on the size of the processor's data caches.
397 local int updatewindow(strm, end, copy)
402 struct inflate_state FAR *state;
405 state = (struct inflate_state FAR *)strm->state;
407 /* if it hasn't been done already, allocate space for the window */
408 if (state->window == Z_NULL) {
409 state->window = (unsigned char FAR *)
410 ZALLOC(strm, 1U << state->wbits,
411 sizeof(unsigned char));
412 if (state->window == Z_NULL) return 1;
415 /* if window not in use yet, initialize */
416 if (state->wsize == 0) {
417 state->wsize = 1U << state->wbits;
422 /* copy state->wsize or less output bytes into the circular window */
423 if (copy >= state->wsize) {
424 zmemcpy(state->window, end - state->wsize, state->wsize);
426 state->whave = state->wsize;
429 dist = state->wsize - state->wnext;
430 if (dist > copy) dist = copy;
431 zmemcpy(state->window + state->wnext, end - copy, dist);
434 zmemcpy(state->window, end - copy, copy);
436 state->whave = state->wsize;
439 state->wnext += dist;
440 if (state->wnext == state->wsize) state->wnext = 0;
441 if (state->whave < state->wsize) state->whave += dist;
447 /* Macros for inflate(): */
449 /* check function to use adler32() for zlib or crc32() for gzip */
451 # define UPDATE(check, buf, len) \
452 (state->flags ? crc32(check, buf, len) : adler32(check, buf, len))
454 # define UPDATE(check, buf, len) adler32(check, buf, len)
457 /* check macros for header crc */
459 # define CRC2(check, word) \
461 hbuf[0] = (unsigned char)(word); \
462 hbuf[1] = (unsigned char)((word) >> 8); \
463 check = crc32(check, hbuf, 2); \
466 # define CRC4(check, word) \
468 hbuf[0] = (unsigned char)(word); \
469 hbuf[1] = (unsigned char)((word) >> 8); \
470 hbuf[2] = (unsigned char)((word) >> 16); \
471 hbuf[3] = (unsigned char)((word) >> 24); \
472 check = crc32(check, hbuf, 4); \
476 /* Load registers with state in inflate() for speed */
479 put = strm->next_out; \
480 left = strm->avail_out; \
481 next = strm->next_in; \
482 have = strm->avail_in; \
483 hold = state->hold; \
484 bits = state->bits; \
487 /* Restore state from registers in inflate() */
490 strm->next_out = put; \
491 strm->avail_out = left; \
492 strm->next_in = next; \
493 strm->avail_in = have; \
494 state->hold = hold; \
495 state->bits = bits; \
498 /* Clear the input bit accumulator */
505 /* Get a byte of input into the bit accumulator, or return from inflate()
506 if there is no input available. */
509 if (have == 0) goto inf_leave; \
511 hold += (unsigned long)(*next++) << bits; \
515 /* Assure that there are at least n bits in the bit accumulator. If there is
516 not enough available input to do that, then return from inflate(). */
517 #define NEEDBITS(n) \
519 while (bits < (unsigned)(n)) \
523 /* Return the low n bits of the bit accumulator (n < 16) */
525 ((unsigned)hold & ((1U << (n)) - 1))
527 /* Remove n bits from the bit accumulator */
528 #define DROPBITS(n) \
531 bits -= (unsigned)(n); \
534 /* Remove zero to seven bits as needed to go to a byte boundary */
542 inflate() uses a state machine to process as much input data and generate as
543 much output data as possible before returning. The state machine is
544 structured roughly as follows:
546 for (;;) switch (state) {
549 if (not enough input data or output space to make progress)
551 ... make progress ...
557 so when inflate() is called again, the same case is attempted again, and
558 if the appropriate resources are provided, the machine proceeds to the
559 next state. The NEEDBITS() macro is usually the way the state evaluates
560 whether it can proceed or should return. NEEDBITS() does the return if
561 the requested bits are not available. The typical use of the BITS macros
565 ... do something with BITS(n) ...
568 where NEEDBITS(n) either returns from inflate() if there isn't enough
569 input left to load n bits into the accumulator, or it continues. BITS(n)
570 gives the low n bits in the accumulator. When done, DROPBITS(n) drops
571 the low n bits off the accumulator. INITBITS() clears the accumulator
572 and sets the number of available bits to zero. BYTEBITS() discards just
573 enough bits to put the accumulator on a byte boundary. After BYTEBITS()
574 and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
576 NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
577 if there is no input available. The decoding of variable length codes uses
578 PULLBYTE() directly in order to pull just enough bytes to decode the next
581 Some states loop until they get enough input, making sure that enough
582 state information is maintained to continue the loop where it left off
583 if NEEDBITS() returns in the loop. For example, want, need, and keep
584 would all have to actually be part of the saved state in case NEEDBITS()
588 while (want < need) {
590 keep[want++] = BITS(n);
596 As shown above, if the next state is also the next case, then the break
599 A state may also return if there is not enough output space available to
600 complete that state. Those states are copying stored data, writing a
601 literal byte, and copying a matching string.
603 When returning, a "goto inf_leave" is used to update the total counters,
604 update the check value, and determine whether any progress has been made
605 during that inflate() call in order to return the proper return code.
606 Progress is defined as a change in either strm->avail_in or strm->avail_out.
607 When there is a window, goto inf_leave will update the window with the last
608 output written. If a goto inf_leave occurs in the middle of decompression
609 and there is no window currently, goto inf_leave will create one and copy
610 output to the window for the next call of inflate().
612 In this implementation, the flush parameter of inflate() only affects the
613 return code (per zlib.h). inflate() always writes as much as possible to
614 strm->next_out, given the space available and the provided input--the effect
615 documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers
616 the allocation of and copying into a sliding window until necessary, which
617 provides the effect documented in zlib.h for Z_FINISH when the entire input
618 stream available. So the only thing the flush parameter actually does is:
619 when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it
620 will return Z_BUF_ERROR if it has not reached the end of the stream.
623 int ZEXPORT inflate(strm, flush)
627 struct inflate_state FAR *state;
628 z_const unsigned char FAR *next; /* next input */
629 unsigned char FAR *put; /* next output */
630 unsigned have, left; /* available input and output */
631 unsigned long hold; /* bit buffer */
632 unsigned bits; /* bits in bit buffer */
633 unsigned in, out; /* save starting available input and output */
634 unsigned copy; /* number of stored or match bytes to copy */
635 unsigned char FAR *from; /* where to copy match bytes from */
636 code here; /* current decoding table entry */
637 code last; /* parent table entry */
638 unsigned len; /* length to copy for repeats, bits to drop */
639 int ret; /* return code */
641 unsigned char hbuf[4]; /* buffer for gzip header crc calculation */
643 static const unsigned short order[19] = /* permutation of code lengths */
644 {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
646 if (inflateStateCheck(strm) || strm->next_out == Z_NULL ||
647 (strm->next_in == Z_NULL && strm->avail_in != 0))
648 return Z_STREAM_ERROR;
650 state = (struct inflate_state FAR *)strm->state;
651 if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */
657 switch (state->mode) {
659 if (state->wrap == 0) {
660 state->mode = TYPEDO;
665 if ((state->wrap & 2) && hold == 0x8b1f) { /* gzip header */
666 if (state->wbits == 0)
668 state->check = crc32(0L, Z_NULL, 0);
669 CRC2(state->check, hold);
674 if (state->head != Z_NULL)
675 state->head->done = -1;
676 if (!(state->wrap & 1) || /* check if zlib header allowed */
680 ((BITS(8) << 8) + (hold >> 8)) % 31) {
681 strm->msg = (char *)"incorrect header check";
685 if (BITS(4) != Z_DEFLATED) {
686 strm->msg = (char *)"unknown compression method";
692 if (state->wbits == 0)
694 if (len > 15 || len > state->wbits) {
695 strm->msg = (char *)"invalid window size";
699 state->dmax = 1U << len;
700 state->flags = 0; /* indicate zlib header */
701 Tracev((stderr, "inflate: zlib header ok\n"));
702 strm->adler = state->check = adler32(0L, Z_NULL, 0);
703 state->mode = hold & 0x200 ? DICTID : TYPE;
709 state->flags = (int)(hold);
710 if ((state->flags & 0xff) != Z_DEFLATED) {
711 strm->msg = (char *)"unknown compression method";
715 if (state->flags & 0xe000) {
716 strm->msg = (char *)"unknown header flags set";
720 if (state->head != Z_NULL)
721 state->head->text = (int)((hold >> 8) & 1);
722 if ((state->flags & 0x0200) && (state->wrap & 4))
723 CRC2(state->check, hold);
728 if (state->head != Z_NULL)
729 state->head->time = hold;
730 if ((state->flags & 0x0200) && (state->wrap & 4))
731 CRC4(state->check, hold);
736 if (state->head != Z_NULL) {
737 state->head->xflags = (int)(hold & 0xff);
738 state->head->os = (int)(hold >> 8);
740 if ((state->flags & 0x0200) && (state->wrap & 4))
741 CRC2(state->check, hold);
745 if (state->flags & 0x0400) {
747 state->length = (unsigned)(hold);
748 if (state->head != Z_NULL)
749 state->head->extra_len = (unsigned)hold;
750 if ((state->flags & 0x0200) && (state->wrap & 4))
751 CRC2(state->check, hold);
754 else if (state->head != Z_NULL)
755 state->head->extra = Z_NULL;
758 if (state->flags & 0x0400) {
759 copy = state->length;
760 if (copy > have) copy = have;
762 if (state->head != Z_NULL &&
763 state->head->extra != Z_NULL) {
764 len = state->head->extra_len - state->length;
765 zmemcpy(state->head->extra + len, next,
766 len + copy > state->head->extra_max ?
767 state->head->extra_max - len : copy);
769 if ((state->flags & 0x0200) && (state->wrap & 4))
770 state->check = crc32(state->check, next, copy);
773 state->length -= copy;
775 if (state->length) goto inf_leave;
780 if (state->flags & 0x0800) {
781 if (have == 0) goto inf_leave;
784 len = (unsigned)(next[copy++]);
785 if (state->head != Z_NULL &&
786 state->head->name != Z_NULL &&
787 state->length < state->head->name_max)
788 state->head->name[state->length++] = (Bytef)len;
789 } while (len && copy < have);
790 if ((state->flags & 0x0200) && (state->wrap & 4))
791 state->check = crc32(state->check, next, copy);
794 if (len) goto inf_leave;
796 else if (state->head != Z_NULL)
797 state->head->name = Z_NULL;
799 state->mode = COMMENT;
801 if (state->flags & 0x1000) {
802 if (have == 0) goto inf_leave;
805 len = (unsigned)(next[copy++]);
806 if (state->head != Z_NULL &&
807 state->head->comment != Z_NULL &&
808 state->length < state->head->comm_max)
809 state->head->comment[state->length++] = (Bytef)len;
810 } while (len && copy < have);
811 if ((state->flags & 0x0200) && (state->wrap & 4))
812 state->check = crc32(state->check, next, copy);
815 if (len) goto inf_leave;
817 else if (state->head != Z_NULL)
818 state->head->comment = Z_NULL;
821 if (state->flags & 0x0200) {
823 if ((state->wrap & 4) && hold != (state->check & 0xffff)) {
824 strm->msg = (char *)"header crc mismatch";
830 if (state->head != Z_NULL) {
831 state->head->hcrc = (int)((state->flags >> 9) & 1);
832 state->head->done = 1;
834 strm->adler = state->check = crc32(0L, Z_NULL, 0);
840 strm->adler = state->check = ZSWAP32(hold);
844 if (state->havedict == 0) {
848 strm->adler = state->check = adler32(0L, Z_NULL, 0);
851 if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
859 state->last = BITS(1);
862 case 0: /* stored block */
863 Tracev((stderr, "inflate: stored block%s\n",
864 state->last ? " (last)" : ""));
865 state->mode = STORED;
867 case 1: /* fixed block */
869 Tracev((stderr, "inflate: fixed codes block%s\n",
870 state->last ? " (last)" : ""));
871 state->mode = LEN_; /* decode codes */
872 if (flush == Z_TREES) {
877 case 2: /* dynamic block */
878 Tracev((stderr, "inflate: dynamic codes block%s\n",
879 state->last ? " (last)" : ""));
883 strm->msg = (char *)"invalid block type";
889 BYTEBITS(); /* go to byte boundary */
891 if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
892 strm->msg = (char *)"invalid stored block lengths";
896 state->length = (unsigned)hold & 0xffff;
897 Tracev((stderr, "inflate: stored length %u\n",
901 if (flush == Z_TREES) goto inf_leave;
905 copy = state->length;
907 if (copy > have) copy = have;
908 if (copy > left) copy = left;
909 if (copy == 0) goto inf_leave;
910 zmemcpy(put, next, copy);
915 state->length -= copy;
918 Tracev((stderr, "inflate: stored end\n"));
923 state->nlen = BITS(5) + 257;
925 state->ndist = BITS(5) + 1;
927 state->ncode = BITS(4) + 4;
929 #ifndef PKZIP_BUG_WORKAROUND
930 if (state->nlen > 286 || state->ndist > 30) {
931 strm->msg = (char *)"too many length or distance symbols";
936 Tracev((stderr, "inflate: table sizes ok\n"));
938 state->mode = LENLENS;
940 while (state->have < state->ncode) {
942 state->lens[order[state->have++]] = (unsigned short)BITS(3);
945 while (state->have < 19)
946 state->lens[order[state->have++]] = 0;
947 state->next = state->codes;
948 state->lencode = (const code FAR *)(state->next);
950 ret = inflate_table(CODES, state->lens, 19, &(state->next),
951 &(state->lenbits), state->work);
953 strm->msg = (char *)"invalid code lengths set";
957 Tracev((stderr, "inflate: code lengths ok\n"));
959 state->mode = CODELENS;
961 while (state->have < state->nlen + state->ndist) {
963 here = state->lencode[BITS(state->lenbits)];
964 if ((unsigned)(here.bits) <= bits) break;
969 state->lens[state->have++] = here.val;
972 if (here.val == 16) {
973 NEEDBITS(here.bits + 2);
975 if (state->have == 0) {
976 strm->msg = (char *)"invalid bit length repeat";
980 len = state->lens[state->have - 1];
984 else if (here.val == 17) {
985 NEEDBITS(here.bits + 3);
992 NEEDBITS(here.bits + 7);
998 if (state->have + copy > state->nlen + state->ndist) {
999 strm->msg = (char *)"invalid bit length repeat";
1004 state->lens[state->have++] = (unsigned short)len;
1008 /* handle error breaks in while */
1009 if (state->mode == BAD) break;
1011 /* check for end-of-block code (better have one) */
1012 if (state->lens[256] == 0) {
1013 strm->msg = (char *)"invalid code -- missing end-of-block";
1018 /* build code tables -- note: do not change the lenbits or distbits
1019 values here (9 and 6) without reading the comments in inftrees.h
1020 concerning the ENOUGH constants, which depend on those values */
1021 state->next = state->codes;
1022 state->lencode = (const code FAR *)(state->next);
1024 ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
1025 &(state->lenbits), state->work);
1027 strm->msg = (char *)"invalid literal/lengths set";
1031 state->distcode = (const code FAR *)(state->next);
1032 state->distbits = 6;
1033 ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
1034 &(state->next), &(state->distbits), state->work);
1036 strm->msg = (char *)"invalid distances set";
1040 Tracev((stderr, "inflate: codes ok\n"));
1042 if (flush == Z_TREES) goto inf_leave;
1046 if (have >= 6 && left >= 258) {
1048 inflate_fast(strm, out);
1050 if (state->mode == TYPE)
1056 here = state->lencode[BITS(state->lenbits)];
1057 if ((unsigned)(here.bits) <= bits) break;
1060 if (here.op && (here.op & 0xf0) == 0) {
1063 here = state->lencode[last.val +
1064 (BITS(last.bits + last.op) >> last.bits)];
1065 if ((unsigned)(last.bits + here.bits) <= bits) break;
1068 DROPBITS(last.bits);
1069 state->back += last.bits;
1071 DROPBITS(here.bits);
1072 state->back += here.bits;
1073 state->length = (unsigned)here.val;
1074 if ((int)(here.op) == 0) {
1075 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
1076 "inflate: literal '%c'\n" :
1077 "inflate: literal 0x%02x\n", here.val));
1082 Tracevv((stderr, "inflate: end of block\n"));
1088 strm->msg = (char *)"invalid literal/length code";
1092 state->extra = (unsigned)(here.op) & 15;
1093 state->mode = LENEXT;
1096 NEEDBITS(state->extra);
1097 state->length += BITS(state->extra);
1098 DROPBITS(state->extra);
1099 state->back += state->extra;
1101 Tracevv((stderr, "inflate: length %u\n", state->length));
1102 state->was = state->length;
1106 here = state->distcode[BITS(state->distbits)];
1107 if ((unsigned)(here.bits) <= bits) break;
1110 if ((here.op & 0xf0) == 0) {
1113 here = state->distcode[last.val +
1114 (BITS(last.bits + last.op) >> last.bits)];
1115 if ((unsigned)(last.bits + here.bits) <= bits) break;
1118 DROPBITS(last.bits);
1119 state->back += last.bits;
1121 DROPBITS(here.bits);
1122 state->back += here.bits;
1124 strm->msg = (char *)"invalid distance code";
1128 state->offset = (unsigned)here.val;
1129 state->extra = (unsigned)(here.op) & 15;
1130 state->mode = DISTEXT;
1133 NEEDBITS(state->extra);
1134 state->offset += BITS(state->extra);
1135 DROPBITS(state->extra);
1136 state->back += state->extra;
1138 #ifdef INFLATE_STRICT
1139 if (state->offset > state->dmax) {
1140 strm->msg = (char *)"invalid distance too far back";
1145 Tracevv((stderr, "inflate: distance %u\n", state->offset));
1146 state->mode = MATCH;
1148 if (left == 0) goto inf_leave;
1150 if (state->offset > copy) { /* copy from window */
1151 copy = state->offset - copy;
1152 if (copy > state->whave) {
1154 strm->msg = (char *)"invalid distance too far back";
1158 #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
1159 Trace((stderr, "inflate.c too far\n"));
1160 copy -= state->whave;
1161 if (copy > state->length) copy = state->length;
1162 if (copy > left) copy = left;
1164 state->length -= copy;
1168 if (state->length == 0) state->mode = LEN;
1172 if (copy > state->wnext) {
1173 copy -= state->wnext;
1174 from = state->window + (state->wsize - copy);
1177 from = state->window + (state->wnext - copy);
1178 if (copy > state->length) copy = state->length;
1180 else { /* copy from output */
1181 from = put - state->offset;
1182 copy = state->length;
1184 if (copy > left) copy = left;
1186 state->length -= copy;
1190 if (state->length == 0) state->mode = LEN;
1193 if (left == 0) goto inf_leave;
1194 *put++ = (unsigned char)(state->length);
1202 strm->total_out += out;
1203 state->total += out;
1204 if ((state->wrap & 4) && out)
1205 strm->adler = state->check =
1206 UPDATE(state->check, put - out, out);
1208 if ((state->wrap & 4) && (
1210 state->flags ? hold :
1212 ZSWAP32(hold)) != state->check) {
1213 strm->msg = (char *)"incorrect data check";
1218 Tracev((stderr, "inflate: check matches trailer\n"));
1221 state->mode = LENGTH;
1223 if (state->wrap && state->flags) {
1225 if ((state->wrap & 4) && hold != (state->total & 0xffffffff)) {
1226 strm->msg = (char *)"incorrect length check";
1231 Tracev((stderr, "inflate: length matches trailer\n"));
1245 return Z_STREAM_ERROR;
1249 Return from inflate(), updating the total counts and the check value.
1250 If there was no progress during the inflate() call, return a buffer
1251 error. Call updatewindow() to create and/or update the window state.
1252 Note: a memory error from inflate() is non-recoverable.
1256 if (state->wsize || (out != strm->avail_out && state->mode < BAD &&
1257 (state->mode < CHECK || flush != Z_FINISH)))
1258 if (updatewindow(strm, strm->next_out, out - strm->avail_out)) {
1262 in -= strm->avail_in;
1263 out -= strm->avail_out;
1264 strm->total_in += in;
1265 strm->total_out += out;
1266 state->total += out;
1267 if ((state->wrap & 4) && out)
1268 strm->adler = state->check =
1269 UPDATE(state->check, strm->next_out - out, out);
1270 strm->data_type = (int)state->bits + (state->last ? 64 : 0) +
1271 (state->mode == TYPE ? 128 : 0) +
1272 (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
1273 if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
1278 int ZEXPORT inflateEnd(strm)
1281 struct inflate_state FAR *state;
1282 if (inflateStateCheck(strm))
1283 return Z_STREAM_ERROR;
1284 state = (struct inflate_state FAR *)strm->state;
1285 if (state->window != Z_NULL) ZFREE(strm, state->window);
1286 ZFREE(strm, strm->state);
1287 strm->state = Z_NULL;
1288 Tracev((stderr, "inflate: end\n"));
1292 int ZEXPORT inflateGetDictionary(strm, dictionary, dictLength)
1297 struct inflate_state FAR *state;
1300 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1301 state = (struct inflate_state FAR *)strm->state;
1303 /* copy dictionary */
1304 if (state->whave && dictionary != Z_NULL) {
1305 zmemcpy(dictionary, state->window + state->wnext,
1306 state->whave - state->wnext);
1307 zmemcpy(dictionary + state->whave - state->wnext,
1308 state->window, state->wnext);
1310 if (dictLength != Z_NULL)
1311 *dictLength = state->whave;
1315 int ZEXPORT inflateSetDictionary(strm, dictionary, dictLength)
1317 const Bytef *dictionary;
1320 struct inflate_state FAR *state;
1321 unsigned long dictid;
1325 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1326 state = (struct inflate_state FAR *)strm->state;
1327 if (state->wrap != 0 && state->mode != DICT)
1328 return Z_STREAM_ERROR;
1330 /* check for correct dictionary identifier */
1331 if (state->mode == DICT) {
1332 dictid = adler32(0L, Z_NULL, 0);
1333 dictid = adler32(dictid, dictionary, dictLength);
1334 if (dictid != state->check)
1335 return Z_DATA_ERROR;
1338 /* copy dictionary to window using updatewindow(), which will amend the
1339 existing dictionary if appropriate */
1340 ret = updatewindow(strm, dictionary + dictLength, dictLength);
1345 state->havedict = 1;
1346 Tracev((stderr, "inflate: dictionary set\n"));
1350 int ZEXPORT inflateGetHeader(strm, head)
1354 struct inflate_state FAR *state;
1357 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1358 state = (struct inflate_state FAR *)strm->state;
1359 if ((state->wrap & 2) == 0) return Z_STREAM_ERROR;
1361 /* save header structure */
1368 Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff. Return when found
1369 or when out of input. When called, *have is the number of pattern bytes
1370 found in order so far, in 0..3. On return *have is updated to the new
1371 state. If on return *have equals four, then the pattern was found and the
1372 return value is how many bytes were read including the last byte of the
1373 pattern. If *have is less than four, then the pattern has not been found
1374 yet and the return value is len. In the latter case, syncsearch() can be
1375 called again with more data and the *have state. *have is initialized to
1376 zero for the first call.
1378 local unsigned syncsearch(have, buf, len)
1380 const unsigned char FAR *buf;
1388 while (next < len && got < 4) {
1389 if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
1401 int ZEXPORT inflateSync(strm)
1404 unsigned len; /* number of bytes to look at or looked at */
1405 int flags; /* temporary to save header status */
1406 unsigned long in, out; /* temporary to save total_in and total_out */
1407 unsigned char buf[4]; /* to restore bit buffer to byte string */
1408 struct inflate_state FAR *state;
1410 /* check parameters */
1411 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1412 state = (struct inflate_state FAR *)strm->state;
1413 if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;
1415 /* if first time, start search in bit buffer */
1416 if (state->mode != SYNC) {
1418 state->hold <<= state->bits & 7;
1419 state->bits -= state->bits & 7;
1421 while (state->bits >= 8) {
1422 buf[len++] = (unsigned char)(state->hold);
1427 syncsearch(&(state->have), buf, len);
1430 /* search available input */
1431 len = syncsearch(&(state->have), strm->next_in, strm->avail_in);
1432 strm->avail_in -= len;
1433 strm->next_in += len;
1434 strm->total_in += len;
1436 /* return no joy or set up to restart inflate() on a new block */
1437 if (state->have != 4) return Z_DATA_ERROR;
1438 if (state->flags == -1)
1439 state->wrap = 0; /* if no header yet, treat as raw */
1441 state->wrap &= ~4; /* no point in computing a check value now */
1442 flags = state->flags;
1443 in = strm->total_in; out = strm->total_out;
1445 strm->total_in = in; strm->total_out = out;
1446 state->flags = flags;
1452 Returns true if inflate is currently at the end of a block generated by
1453 Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
1454 implementation to provide an additional safety check. PPP uses
1455 Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored
1456 block. When decompressing, PPP checks that at the end of input packet,
1457 inflate is waiting for these length bytes.
1459 int ZEXPORT inflateSyncPoint(strm)
1462 struct inflate_state FAR *state;
1464 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1465 state = (struct inflate_state FAR *)strm->state;
1466 return state->mode == STORED && state->bits == 0;
1469 int ZEXPORT inflateCopy(dest, source)
1473 struct inflate_state FAR *state;
1474 struct inflate_state FAR *copy;
1475 unsigned char FAR *window;
1479 if (inflateStateCheck(source) || dest == Z_NULL)
1480 return Z_STREAM_ERROR;
1481 state = (struct inflate_state FAR *)source->state;
1483 /* allocate space */
1484 copy = (struct inflate_state FAR *)
1485 ZALLOC(source, 1, sizeof(struct inflate_state));
1486 if (copy == Z_NULL) return Z_MEM_ERROR;
1488 if (state->window != Z_NULL) {
1489 window = (unsigned char FAR *)
1490 ZALLOC(source, 1U << state->wbits, sizeof(unsigned char));
1491 if (window == Z_NULL) {
1492 ZFREE(source, copy);
1498 zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
1499 zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state));
1501 if (state->lencode >= state->codes &&
1502 state->lencode <= state->codes + ENOUGH - 1) {
1503 copy->lencode = copy->codes + (state->lencode - state->codes);
1504 copy->distcode = copy->codes + (state->distcode - state->codes);
1506 copy->next = copy->codes + (state->next - state->codes);
1507 if (window != Z_NULL) {
1508 wsize = 1U << state->wbits;
1509 zmemcpy(window, state->window, wsize);
1511 copy->window = window;
1512 dest->state = (struct internal_state FAR *)copy;
1516 int ZEXPORT inflateUndermine(strm, subvert)
1520 struct inflate_state FAR *state;
1522 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1523 state = (struct inflate_state FAR *)strm->state;
1524 #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
1525 state->sane = !subvert;
1530 return Z_DATA_ERROR;
1534 int ZEXPORT inflateValidate(strm, check)
1538 struct inflate_state FAR *state;
1540 if (inflateStateCheck(strm)) return Z_STREAM_ERROR;
1541 state = (struct inflate_state FAR *)strm->state;
1542 if (check && state->wrap)
1549 long ZEXPORT inflateMark(strm)
1552 struct inflate_state FAR *state;
1554 if (inflateStateCheck(strm))
1556 state = (struct inflate_state FAR *)strm->state;
1557 return (long)(((unsigned long)((long)state->back)) << 16) +
1558 (state->mode == COPY ? state->length :
1559 (state->mode == MATCH ? state->was - state->length : 0));
1562 unsigned long ZEXPORT inflateCodesUsed(strm)
1565 struct inflate_state FAR *state;
1566 if (inflateStateCheck(strm)) return (unsigned long)-1;
1567 state = (struct inflate_state FAR *)strm->state;
1568 return (unsigned long)(state->next - state->codes);