1 /* inflate.c -- zlib decompression
2 * Copyright (C) 1995-2012 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, const unsigned char FAR *end,
99 void makefixed OF((void));
101 local unsigned syncsearch OF((unsigned FAR *have, const unsigned char FAR *buf,
104 int ZEXPORT inflateResetKeep(strm)
107 struct inflate_state FAR *state;
109 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
110 state = (struct inflate_state FAR *)strm->state;
111 strm->total_in = strm->total_out = state->total = 0;
113 if (state->wrap) /* to support ill-conceived Java test suite */
114 strm->adler = state->wrap & 1;
118 state->dmax = 32768U;
119 state->head = Z_NULL;
122 state->lencode = state->distcode = state->next = state->codes;
125 Tracev((stderr, "inflate: reset\n"));
129 int ZEXPORT inflateReset(strm)
132 struct inflate_state FAR *state;
134 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
135 state = (struct inflate_state FAR *)strm->state;
139 return inflateResetKeep(strm);
142 int ZEXPORT inflateReset2(strm, windowBits)
147 struct inflate_state FAR *state;
150 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
151 state = (struct inflate_state FAR *)strm->state;
153 /* extract wrap request from windowBits parameter */
154 if (windowBits < 0) {
156 windowBits = -windowBits;
159 wrap = (windowBits >> 4) + 1;
166 /* set number of window bits, free window if different */
167 if (windowBits && (windowBits < 8 || windowBits > 15))
168 return Z_STREAM_ERROR;
169 if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) {
170 ZFREE(strm, state->window);
171 state->window = Z_NULL;
174 /* update state and reset the rest of it */
176 state->wbits = (unsigned)windowBits;
177 return inflateReset(strm);
180 int ZEXPORT inflateInit2_(strm, windowBits, version, stream_size)
187 struct inflate_state FAR *state;
189 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
190 stream_size != (int)(sizeof(z_stream)))
191 return Z_VERSION_ERROR;
192 if (strm == Z_NULL) return Z_STREAM_ERROR;
193 strm->msg = Z_NULL; /* in case we return an error */
194 if (strm->zalloc == (alloc_func)0) {
196 return Z_STREAM_ERROR;
198 strm->zalloc = zcalloc;
199 strm->opaque = (voidpf)0;
202 if (strm->zfree == (free_func)0)
204 return Z_STREAM_ERROR;
206 strm->zfree = zcfree;
208 state = (struct inflate_state FAR *)
209 ZALLOC(strm, 1, sizeof(struct inflate_state));
210 if (state == Z_NULL) return Z_MEM_ERROR;
211 Tracev((stderr, "inflate: allocated\n"));
212 strm->state = (struct internal_state FAR *)state;
213 state->window = Z_NULL;
214 ret = inflateReset2(strm, windowBits);
217 strm->state = Z_NULL;
222 int ZEXPORT inflateInit_(strm, version, stream_size)
227 return inflateInit2_(strm, DEF_WBITS, version, stream_size);
230 int ZEXPORT inflatePrime(strm, bits, value)
235 struct inflate_state FAR *state;
237 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
238 state = (struct inflate_state FAR *)strm->state;
244 if (bits > 16 || state->bits + bits > 32) return Z_STREAM_ERROR;
245 value &= (1L << bits) - 1;
246 state->hold += value << state->bits;
252 Return state with length and distance decoding tables and index sizes set to
253 fixed code decoding. Normally this returns fixed tables from inffixed.h.
254 If BUILDFIXED is defined, then instead this routine builds the tables the
255 first time it's called, and returns those tables the first time and
256 thereafter. This reduces the size of the code by about 2K bytes, in
257 exchange for a little execution time. However, BUILDFIXED should not be
258 used for threaded applications, since the rewriting of the tables and virgin
259 may not be thread-safe.
261 local void fixedtables(state)
262 struct inflate_state FAR *state;
265 static int virgin = 1;
266 static code *lenfix, *distfix;
267 static code fixed[544];
269 /* build fixed huffman tables if first call (may not be thread safe) */
274 /* literal/length table */
276 while (sym < 144) state->lens[sym++] = 8;
277 while (sym < 256) state->lens[sym++] = 9;
278 while (sym < 280) state->lens[sym++] = 7;
279 while (sym < 288) state->lens[sym++] = 8;
283 inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
287 while (sym < 32) state->lens[sym++] = 5;
290 inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
292 /* do this just once */
295 #else /* !BUILDFIXED */
296 # include "inffixed.h"
297 #endif /* BUILDFIXED */
298 state->lencode = lenfix;
300 state->distcode = distfix;
308 Write out the inffixed.h that is #include'd above. Defining MAKEFIXED also
309 defines BUILDFIXED, so the tables are built on the fly. makefixed() writes
310 those tables to stdout, which would be piped to inffixed.h. A small program
311 can simply call makefixed to do this:
313 void makefixed(void);
321 Then that can be linked with zlib built with MAKEFIXED defined and run:
328 struct inflate_state state;
331 puts(" /* inffixed.h -- table for decoding fixed codes");
332 puts(" * Generated automatically by makefixed().");
335 puts(" /* WARNING: this file should *not* be used by applications.");
336 puts(" It is part of the implementation of this library and is");
337 puts(" subject to change. Applications should only use zlib.h.");
341 printf(" static const code lenfix[%u] = {", size);
344 if ((low % 7) == 0) printf("\n ");
345 printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op,
346 state.lencode[low].bits, state.lencode[low].val);
347 if (++low == size) break;
352 printf("\n static const code distfix[%u] = {", size);
355 if ((low % 6) == 0) printf("\n ");
356 printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits,
357 state.distcode[low].val);
358 if (++low == size) break;
363 #endif /* MAKEFIXED */
366 Update the window with the last wsize (normally 32K) bytes written before
367 returning. If window does not exist yet, create it. This is only called
368 when a window is already in use, or when output has been written during this
369 inflate call, but the end of the deflate stream has not been reached yet.
370 It is also called to create a window for dictionary data when a dictionary
373 Providing output buffers larger than 32K to inflate() should provide a speed
374 advantage, since only the last 32K of output is copied to the sliding window
375 upon return from inflate(), and since all distances after the first 32K of
376 output will fall in the output data, making match copies simpler and faster.
377 The advantage may be dependent on the size of the processor's data caches.
379 local int updatewindow(strm, end, copy)
384 struct inflate_state FAR *state;
387 state = (struct inflate_state FAR *)strm->state;
389 /* if it hasn't been done already, allocate space for the window */
390 if (state->window == Z_NULL) {
391 state->window = (unsigned char FAR *)
392 ZALLOC(strm, 1U << state->wbits,
393 sizeof(unsigned char));
394 if (state->window == Z_NULL) return 1;
397 /* if window not in use yet, initialize */
398 if (state->wsize == 0) {
399 state->wsize = 1U << state->wbits;
404 /* copy state->wsize or less output bytes into the circular window */
405 if (copy >= state->wsize) {
406 zmemcpy(state->window, end - state->wsize, state->wsize);
408 state->whave = state->wsize;
411 dist = state->wsize - state->wnext;
412 if (dist > copy) dist = copy;
413 zmemcpy(state->window + state->wnext, end - copy, dist);
416 zmemcpy(state->window, end - copy, copy);
418 state->whave = state->wsize;
421 state->wnext += dist;
422 if (state->wnext == state->wsize) state->wnext = 0;
423 if (state->whave < state->wsize) state->whave += dist;
429 /* Macros for inflate(): */
431 /* check function to use adler32() for zlib or crc32() for gzip */
433 # define UPDATE(check, buf, len) \
434 (state->flags ? crc32(check, buf, len) : adler32(check, buf, len))
436 # define UPDATE(check, buf, len) adler32(check, buf, len)
439 /* check macros for header crc */
441 # define CRC2(check, word) \
443 hbuf[0] = (unsigned char)(word); \
444 hbuf[1] = (unsigned char)((word) >> 8); \
445 check = crc32(check, hbuf, 2); \
448 # define CRC4(check, word) \
450 hbuf[0] = (unsigned char)(word); \
451 hbuf[1] = (unsigned char)((word) >> 8); \
452 hbuf[2] = (unsigned char)((word) >> 16); \
453 hbuf[3] = (unsigned char)((word) >> 24); \
454 check = crc32(check, hbuf, 4); \
458 /* Load registers with state in inflate() for speed */
461 put = strm->next_out; \
462 left = strm->avail_out; \
463 next = strm->next_in; \
464 have = strm->avail_in; \
465 hold = state->hold; \
466 bits = state->bits; \
469 /* Restore state from registers in inflate() */
472 strm->next_out = put; \
473 strm->avail_out = left; \
474 strm->next_in = next; \
475 strm->avail_in = have; \
476 state->hold = hold; \
477 state->bits = bits; \
480 /* Clear the input bit accumulator */
487 /* Get a byte of input into the bit accumulator, or return from inflate()
488 if there is no input available. */
491 if (have == 0) goto inf_leave; \
493 hold += (unsigned long)(*next++) << bits; \
497 /* Assure that there are at least n bits in the bit accumulator. If there is
498 not enough available input to do that, then return from inflate(). */
499 #define NEEDBITS(n) \
501 while (bits < (unsigned)(n)) \
505 /* Return the low n bits of the bit accumulator (n < 16) */
507 ((unsigned)hold & ((1U << (n)) - 1))
509 /* Remove n bits from the bit accumulator */
510 #define DROPBITS(n) \
513 bits -= (unsigned)(n); \
516 /* Remove zero to seven bits as needed to go to a byte boundary */
524 inflate() uses a state machine to process as much input data and generate as
525 much output data as possible before returning. The state machine is
526 structured roughly as follows:
528 for (;;) switch (state) {
531 if (not enough input data or output space to make progress)
533 ... make progress ...
539 so when inflate() is called again, the same case is attempted again, and
540 if the appropriate resources are provided, the machine proceeds to the
541 next state. The NEEDBITS() macro is usually the way the state evaluates
542 whether it can proceed or should return. NEEDBITS() does the return if
543 the requested bits are not available. The typical use of the BITS macros
547 ... do something with BITS(n) ...
550 where NEEDBITS(n) either returns from inflate() if there isn't enough
551 input left to load n bits into the accumulator, or it continues. BITS(n)
552 gives the low n bits in the accumulator. When done, DROPBITS(n) drops
553 the low n bits off the accumulator. INITBITS() clears the accumulator
554 and sets the number of available bits to zero. BYTEBITS() discards just
555 enough bits to put the accumulator on a byte boundary. After BYTEBITS()
556 and a NEEDBITS(8), then BITS(8) would return the next byte in the stream.
558 NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return
559 if there is no input available. The decoding of variable length codes uses
560 PULLBYTE() directly in order to pull just enough bytes to decode the next
563 Some states loop until they get enough input, making sure that enough
564 state information is maintained to continue the loop where it left off
565 if NEEDBITS() returns in the loop. For example, want, need, and keep
566 would all have to actually be part of the saved state in case NEEDBITS()
570 while (want < need) {
572 keep[want++] = BITS(n);
578 As shown above, if the next state is also the next case, then the break
581 A state may also return if there is not enough output space available to
582 complete that state. Those states are copying stored data, writing a
583 literal byte, and copying a matching string.
585 When returning, a "goto inf_leave" is used to update the total counters,
586 update the check value, and determine whether any progress has been made
587 during that inflate() call in order to return the proper return code.
588 Progress is defined as a change in either strm->avail_in or strm->avail_out.
589 When there is a window, goto inf_leave will update the window with the last
590 output written. If a goto inf_leave occurs in the middle of decompression
591 and there is no window currently, goto inf_leave will create one and copy
592 output to the window for the next call of inflate().
594 In this implementation, the flush parameter of inflate() only affects the
595 return code (per zlib.h). inflate() always writes as much as possible to
596 strm->next_out, given the space available and the provided input--the effect
597 documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers
598 the allocation of and copying into a sliding window until necessary, which
599 provides the effect documented in zlib.h for Z_FINISH when the entire input
600 stream available. So the only thing the flush parameter actually does is:
601 when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it
602 will return Z_BUF_ERROR if it has not reached the end of the stream.
605 int ZEXPORT inflate(strm, flush)
609 struct inflate_state FAR *state;
610 z_const unsigned char FAR *next; /* next input */
611 unsigned char FAR *put; /* next output */
612 unsigned have, left; /* available input and output */
613 unsigned long hold; /* bit buffer */
614 unsigned bits; /* bits in bit buffer */
615 unsigned in, out; /* save starting available input and output */
616 unsigned copy; /* number of stored or match bytes to copy */
617 unsigned char FAR *from; /* where to copy match bytes from */
618 code here; /* current decoding table entry */
619 code last; /* parent table entry */
620 unsigned len; /* length to copy for repeats, bits to drop */
621 int ret; /* return code */
623 unsigned char hbuf[4]; /* buffer for gzip header crc calculation */
625 static const unsigned short order[19] = /* permutation of code lengths */
626 {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
628 if (strm == Z_NULL || strm->state == Z_NULL || strm->next_out == Z_NULL ||
629 (strm->next_in == Z_NULL && strm->avail_in != 0))
630 return Z_STREAM_ERROR;
632 state = (struct inflate_state FAR *)strm->state;
633 if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */
639 switch (state->mode) {
641 if (state->wrap == 0) {
642 state->mode = TYPEDO;
647 if ((state->wrap & 2) && hold == 0x8b1f) { /* gzip header */
648 state->check = crc32(0L, Z_NULL, 0);
649 CRC2(state->check, hold);
654 state->flags = 0; /* expect zlib header */
655 if (state->head != Z_NULL)
656 state->head->done = -1;
657 if (!(state->wrap & 1) || /* check if zlib header allowed */
661 ((BITS(8) << 8) + (hold >> 8)) % 31) {
662 strm->msg = (char *)"incorrect header check";
666 if (BITS(4) != Z_DEFLATED) {
667 strm->msg = (char *)"unknown compression method";
673 if (state->wbits == 0)
675 else if (len > state->wbits) {
676 strm->msg = (char *)"invalid window size";
680 state->dmax = 1U << len;
681 Tracev((stderr, "inflate: zlib header ok\n"));
682 strm->adler = state->check = adler32(0L, Z_NULL, 0);
683 state->mode = hold & 0x200 ? DICTID : TYPE;
689 state->flags = (int)(hold);
690 if ((state->flags & 0xff) != Z_DEFLATED) {
691 strm->msg = (char *)"unknown compression method";
695 if (state->flags & 0xe000) {
696 strm->msg = (char *)"unknown header flags set";
700 if (state->head != Z_NULL)
701 state->head->text = (int)((hold >> 8) & 1);
702 if (state->flags & 0x0200) CRC2(state->check, hold);
708 if (state->head != Z_NULL)
709 state->head->time = hold;
710 if (state->flags & 0x0200) CRC4(state->check, hold);
716 if (state->head != Z_NULL) {
717 state->head->xflags = (int)(hold & 0xff);
718 state->head->os = (int)(hold >> 8);
720 if (state->flags & 0x0200) CRC2(state->check, hold);
725 if (state->flags & 0x0400) {
727 state->length = (unsigned)(hold);
728 if (state->head != Z_NULL)
729 state->head->extra_len = (unsigned)hold;
730 if (state->flags & 0x0200) CRC2(state->check, hold);
733 else if (state->head != Z_NULL)
734 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;
761 if (state->flags & 0x0800) {
762 if (have == 0) goto inf_leave;
765 len = (unsigned)(next[copy++]);
766 if (state->head != Z_NULL &&
767 state->head->name != Z_NULL &&
768 state->length < state->head->name_max)
769 state->head->name[state->length++] = len;
770 } while (len && copy < have);
771 if (state->flags & 0x0200)
772 state->check = crc32(state->check, next, copy);
775 if (len) goto inf_leave;
777 else if (state->head != Z_NULL)
778 state->head->name = Z_NULL;
780 state->mode = COMMENT;
783 if (state->flags & 0x1000) {
784 if (have == 0) goto inf_leave;
787 len = (unsigned)(next[copy++]);
788 if (state->head != Z_NULL &&
789 state->head->comment != Z_NULL &&
790 state->length < state->head->comm_max)
791 state->head->comment[state->length++] = len;
792 } while (len && copy < have);
793 if (state->flags & 0x0200)
794 state->check = crc32(state->check, next, copy);
797 if (len) goto inf_leave;
799 else if (state->head != Z_NULL)
800 state->head->comment = Z_NULL;
804 if (state->flags & 0x0200) {
806 if (hold != (state->check & 0xffff)) {
807 strm->msg = (char *)"header crc mismatch";
813 if (state->head != Z_NULL) {
814 state->head->hcrc = (int)((state->flags >> 9) & 1);
815 state->head->done = 1;
817 strm->adler = state->check = crc32(0L, Z_NULL, 0);
823 strm->adler = state->check = ZSWAP32(hold);
828 if (state->havedict == 0) {
832 strm->adler = state->check = adler32(0L, Z_NULL, 0);
836 if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave;
845 state->last = BITS(1);
848 case 0: /* stored block */
849 Tracev((stderr, "inflate: stored block%s\n",
850 state->last ? " (last)" : ""));
851 state->mode = STORED;
853 case 1: /* fixed block */
855 Tracev((stderr, "inflate: fixed codes block%s\n",
856 state->last ? " (last)" : ""));
857 state->mode = LEN_; /* decode codes */
858 if (flush == Z_TREES) {
863 case 2: /* dynamic block */
864 Tracev((stderr, "inflate: dynamic codes block%s\n",
865 state->last ? " (last)" : ""));
869 strm->msg = (char *)"invalid block type";
875 BYTEBITS(); /* go to byte boundary */
877 if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
878 strm->msg = (char *)"invalid stored block lengths";
882 state->length = (unsigned)hold & 0xffff;
883 Tracev((stderr, "inflate: stored length %u\n",
887 if (flush == Z_TREES) goto inf_leave;
893 copy = state->length;
895 if (copy > have) copy = have;
896 if (copy > left) copy = left;
897 if (copy == 0) goto inf_leave;
898 zmemcpy(put, next, copy);
903 state->length -= copy;
906 Tracev((stderr, "inflate: stored end\n"));
911 state->nlen = BITS(5) + 257;
913 state->ndist = BITS(5) + 1;
915 state->ncode = BITS(4) + 4;
917 #ifndef PKZIP_BUG_WORKAROUND
918 if (state->nlen > 286 || state->ndist > 30) {
919 strm->msg = (char *)"too many length or distance symbols";
924 Tracev((stderr, "inflate: table sizes ok\n"));
926 state->mode = LENLENS;
929 while (state->have < state->ncode) {
931 state->lens[order[state->have++]] = (unsigned short)BITS(3);
934 while (state->have < 19)
935 state->lens[order[state->have++]] = 0;
936 state->next = state->codes;
937 state->lencode = (const code FAR *)(state->next);
939 ret = inflate_table(CODES, state->lens, 19, &(state->next),
940 &(state->lenbits), state->work);
942 strm->msg = (char *)"invalid code lengths set";
946 Tracev((stderr, "inflate: code lengths ok\n"));
948 state->mode = CODELENS;
951 while (state->have < state->nlen + state->ndist) {
953 here = state->lencode[BITS(state->lenbits)];
954 if ((unsigned)(here.bits) <= bits) break;
959 state->lens[state->have++] = here.val;
962 if (here.val == 16) {
963 NEEDBITS(here.bits + 2);
965 if (state->have == 0) {
966 strm->msg = (char *)"invalid bit length repeat";
970 len = state->lens[state->have - 1];
974 else if (here.val == 17) {
975 NEEDBITS(here.bits + 3);
982 NEEDBITS(here.bits + 7);
988 if (state->have + copy > state->nlen + state->ndist) {
989 strm->msg = (char *)"invalid bit length repeat";
994 state->lens[state->have++] = (unsigned short)len;
998 /* handle error breaks in while */
999 if (state->mode == BAD) break;
1001 /* check for end-of-block code (better have one) */
1002 if (state->lens[256] == 0) {
1003 strm->msg = (char *)"invalid code -- missing end-of-block";
1008 /* build code tables -- note: do not change the lenbits or distbits
1009 values here (9 and 6) without reading the comments in inftrees.h
1010 concerning the ENOUGH constants, which depend on those values */
1011 state->next = state->codes;
1012 state->lencode = (const code FAR *)(state->next);
1014 ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
1015 &(state->lenbits), state->work);
1017 strm->msg = (char *)"invalid literal/lengths set";
1021 state->distcode = (const code FAR *)(state->next);
1022 state->distbits = 6;
1023 ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
1024 &(state->next), &(state->distbits), state->work);
1026 strm->msg = (char *)"invalid distances set";
1030 Tracev((stderr, "inflate: codes ok\n"));
1032 if (flush == Z_TREES) goto inf_leave;
1038 if (have >= 6 && left >= 258) {
1040 inflate_fast(strm, out);
1042 if (state->mode == TYPE)
1048 here = state->lencode[BITS(state->lenbits)];
1049 if ((unsigned)(here.bits) <= bits) break;
1052 if (here.op && (here.op & 0xf0) == 0) {
1055 here = state->lencode[last.val +
1056 (BITS(last.bits + last.op) >> last.bits)];
1057 if ((unsigned)(last.bits + here.bits) <= bits) break;
1060 DROPBITS(last.bits);
1061 state->back += last.bits;
1063 DROPBITS(here.bits);
1064 state->back += here.bits;
1065 state->length = (unsigned)here.val;
1066 if ((int)(here.op) == 0) {
1067 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
1068 "inflate: literal '%c'\n" :
1069 "inflate: literal 0x%02x\n", here.val));
1074 Tracevv((stderr, "inflate: end of block\n"));
1080 strm->msg = (char *)"invalid literal/length code";
1084 state->extra = (unsigned)(here.op) & 15;
1085 state->mode = LENEXT;
1089 NEEDBITS(state->extra);
1090 state->length += BITS(state->extra);
1091 DROPBITS(state->extra);
1092 state->back += state->extra;
1094 Tracevv((stderr, "inflate: length %u\n", state->length));
1095 state->was = state->length;
1100 here = state->distcode[BITS(state->distbits)];
1101 if ((unsigned)(here.bits) <= bits) break;
1104 if ((here.op & 0xf0) == 0) {
1107 here = state->distcode[last.val +
1108 (BITS(last.bits + last.op) >> last.bits)];
1109 if ((unsigned)(last.bits + here.bits) <= bits) break;
1112 DROPBITS(last.bits);
1113 state->back += last.bits;
1115 DROPBITS(here.bits);
1116 state->back += here.bits;
1118 strm->msg = (char *)"invalid distance code";
1122 state->offset = (unsigned)here.val;
1123 state->extra = (unsigned)(here.op) & 15;
1124 state->mode = DISTEXT;
1128 NEEDBITS(state->extra);
1129 state->offset += BITS(state->extra);
1130 DROPBITS(state->extra);
1131 state->back += state->extra;
1133 #ifdef INFLATE_STRICT
1134 if (state->offset > state->dmax) {
1135 strm->msg = (char *)"invalid distance too far back";
1140 Tracevv((stderr, "inflate: distance %u\n", state->offset));
1141 state->mode = MATCH;
1144 if (left == 0) goto inf_leave;
1146 if (state->offset > copy) { /* copy from window */
1147 copy = state->offset - copy;
1148 if (copy > state->whave) {
1150 strm->msg = (char *)"invalid distance too far back";
1154 #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
1155 Trace((stderr, "inflate.c too far\n"));
1156 copy -= state->whave;
1157 if (copy > state->length) copy = state->length;
1158 if (copy > left) copy = left;
1160 state->length -= copy;
1164 if (state->length == 0) state->mode = LEN;
1168 if (copy > state->wnext) {
1169 copy -= state->wnext;
1170 from = state->window + (state->wsize - copy);
1173 from = state->window + (state->wnext - copy);
1174 if (copy > state->length) copy = state->length;
1176 else { /* copy from output */
1177 from = put - state->offset;
1178 copy = state->length;
1180 if (copy > left) copy = left;
1182 state->length -= copy;
1186 if (state->length == 0) state->mode = LEN;
1189 if (left == 0) goto inf_leave;
1190 *put++ = (unsigned char)(state->length);
1198 strm->total_out += out;
1199 state->total += out;
1201 strm->adler = state->check =
1202 UPDATE(state->check, put - out, out);
1206 state->flags ? hold :
1208 ZSWAP32(hold)) != state->check) {
1209 strm->msg = (char *)"incorrect data check";
1214 Tracev((stderr, "inflate: check matches trailer\n"));
1217 state->mode = LENGTH;
1220 if (state->wrap && state->flags) {
1222 if (hold != (state->total & 0xffffffffUL)) {
1223 strm->msg = (char *)"incorrect length check";
1228 Tracev((stderr, "inflate: length matches trailer\n"));
1243 return Z_STREAM_ERROR;
1247 Return from inflate(), updating the total counts and the check value.
1248 If there was no progress during the inflate() call, return a buffer
1249 error. Call updatewindow() to create and/or update the window state.
1250 Note: a memory error from inflate() is non-recoverable.
1254 if (state->wsize || (out != strm->avail_out && state->mode < BAD &&
1255 (state->mode < CHECK || flush != Z_FINISH)))
1256 if (updatewindow(strm, strm->next_out, out - strm->avail_out)) {
1260 in -= strm->avail_in;
1261 out -= strm->avail_out;
1262 strm->total_in += in;
1263 strm->total_out += out;
1264 state->total += out;
1265 if (state->wrap && out)
1266 strm->adler = state->check =
1267 UPDATE(state->check, strm->next_out - out, out);
1268 strm->data_type = state->bits + (state->last ? 64 : 0) +
1269 (state->mode == TYPE ? 128 : 0) +
1270 (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0);
1271 if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK)
1276 int ZEXPORT inflateEnd(strm)
1279 struct inflate_state FAR *state;
1280 if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
1281 return Z_STREAM_ERROR;
1282 state = (struct inflate_state FAR *)strm->state;
1283 if (state->window != Z_NULL) ZFREE(strm, state->window);
1284 ZFREE(strm, strm->state);
1285 strm->state = Z_NULL;
1286 Tracev((stderr, "inflate: end\n"));
1290 int ZEXPORT inflateGetDictionary(strm, dictionary, dictLength)
1295 struct inflate_state FAR *state;
1298 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1299 state = (struct inflate_state FAR *)strm->state;
1301 /* copy dictionary */
1302 if (state->whave && dictionary != Z_NULL) {
1303 zmemcpy(dictionary, state->window + state->wnext,
1304 state->whave - state->wnext);
1305 zmemcpy(dictionary + state->whave - state->wnext,
1306 state->window, state->wnext);
1308 if (dictLength != Z_NULL)
1309 *dictLength = state->whave;
1313 int ZEXPORT inflateSetDictionary(strm, dictionary, dictLength)
1315 const Bytef *dictionary;
1318 struct inflate_state FAR *state;
1319 unsigned long dictid;
1323 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1324 state = (struct inflate_state FAR *)strm->state;
1325 if (state->wrap != 0 && state->mode != DICT)
1326 return Z_STREAM_ERROR;
1328 /* check for correct dictionary identifier */
1329 if (state->mode == DICT) {
1330 dictid = adler32(0L, Z_NULL, 0);
1331 dictid = adler32(dictid, dictionary, dictLength);
1332 if (dictid != state->check)
1333 return Z_DATA_ERROR;
1336 /* copy dictionary to window using updatewindow(), which will amend the
1337 existing dictionary if appropriate */
1338 ret = updatewindow(strm, dictionary + dictLength, dictLength);
1343 state->havedict = 1;
1344 Tracev((stderr, "inflate: dictionary set\n"));
1348 int ZEXPORT inflateGetHeader(strm, head)
1352 struct inflate_state FAR *state;
1355 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1356 state = (struct inflate_state FAR *)strm->state;
1357 if ((state->wrap & 2) == 0) return Z_STREAM_ERROR;
1359 /* save header structure */
1366 Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff. Return when found
1367 or when out of input. When called, *have is the number of pattern bytes
1368 found in order so far, in 0..3. On return *have is updated to the new
1369 state. If on return *have equals four, then the pattern was found and the
1370 return value is how many bytes were read including the last byte of the
1371 pattern. If *have is less than four, then the pattern has not been found
1372 yet and the return value is len. In the latter case, syncsearch() can be
1373 called again with more data and the *have state. *have is initialized to
1374 zero for the first call.
1376 local unsigned syncsearch(have, buf, len)
1378 const unsigned char FAR *buf;
1386 while (next < len && got < 4) {
1387 if ((int)(buf[next]) == (got < 2 ? 0 : 0xff))
1399 int ZEXPORT inflateSync(strm)
1402 unsigned len; /* number of bytes to look at or looked at */
1403 unsigned long in, out; /* temporary to save total_in and total_out */
1404 unsigned char buf[4]; /* to restore bit buffer to byte string */
1405 struct inflate_state FAR *state;
1407 /* check parameters */
1408 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1409 state = (struct inflate_state FAR *)strm->state;
1410 if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR;
1412 /* if first time, start search in bit buffer */
1413 if (state->mode != SYNC) {
1415 state->hold <<= state->bits & 7;
1416 state->bits -= state->bits & 7;
1418 while (state->bits >= 8) {
1419 buf[len++] = (unsigned char)(state->hold);
1424 syncsearch(&(state->have), buf, len);
1427 /* search available input */
1428 len = syncsearch(&(state->have), strm->next_in, strm->avail_in);
1429 strm->avail_in -= len;
1430 strm->next_in += len;
1431 strm->total_in += len;
1433 /* return no joy or set up to restart inflate() on a new block */
1434 if (state->have != 4) return Z_DATA_ERROR;
1435 in = strm->total_in; out = strm->total_out;
1437 strm->total_in = in; strm->total_out = out;
1443 Returns true if inflate is currently at the end of a block generated by
1444 Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP
1445 implementation to provide an additional safety check. PPP uses
1446 Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored
1447 block. When decompressing, PPP checks that at the end of input packet,
1448 inflate is waiting for these length bytes.
1450 int ZEXPORT inflateSyncPoint(strm)
1453 struct inflate_state FAR *state;
1455 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1456 state = (struct inflate_state FAR *)strm->state;
1457 return state->mode == STORED && state->bits == 0;
1460 int ZEXPORT inflateCopy(dest, source)
1464 struct inflate_state FAR *state;
1465 struct inflate_state FAR *copy;
1466 unsigned char FAR *window;
1470 if (dest == Z_NULL || source == Z_NULL || source->state == Z_NULL ||
1471 source->zalloc == (alloc_func)0 || source->zfree == (free_func)0)
1472 return Z_STREAM_ERROR;
1473 state = (struct inflate_state FAR *)source->state;
1475 /* allocate space */
1476 copy = (struct inflate_state FAR *)
1477 ZALLOC(source, 1, sizeof(struct inflate_state));
1478 if (copy == Z_NULL) return Z_MEM_ERROR;
1480 if (state->window != Z_NULL) {
1481 window = (unsigned char FAR *)
1482 ZALLOC(source, 1U << state->wbits, sizeof(unsigned char));
1483 if (window == Z_NULL) {
1484 ZFREE(source, copy);
1490 zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
1491 zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state));
1492 if (state->lencode >= state->codes &&
1493 state->lencode <= state->codes + ENOUGH - 1) {
1494 copy->lencode = copy->codes + (state->lencode - state->codes);
1495 copy->distcode = copy->codes + (state->distcode - state->codes);
1497 copy->next = copy->codes + (state->next - state->codes);
1498 if (window != Z_NULL) {
1499 wsize = 1U << state->wbits;
1500 zmemcpy(window, state->window, wsize);
1502 copy->window = window;
1503 dest->state = (struct internal_state FAR *)copy;
1507 int ZEXPORT inflateUndermine(strm, subvert)
1511 struct inflate_state FAR *state;
1513 if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
1514 state = (struct inflate_state FAR *)strm->state;
1515 state->sane = !subvert;
1516 #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
1520 return Z_DATA_ERROR;
1524 long ZEXPORT inflateMark(strm)
1527 struct inflate_state FAR *state;
1529 if (strm == Z_NULL || strm->state == Z_NULL)
1530 return (long)(((unsigned long)0 - 1) << 16);
1531 state = (struct inflate_state FAR *)strm->state;
1532 return (long)(((unsigned long)((long)state->back)) << 16) +
1533 (state->mode == COPY ? state->length :
1534 (state->mode == MATCH ? state->was - state->length : 0));