1 | /* inflate.c -- zlib decompression |
2 | * Copyright (C) 1995-2022 Mark Adler |
3 | * For conditions of distribution and use, see copyright notice in zlib.h |
4 | */ |
5 | |
6 | /* |
7 | * Change history: |
8 | * |
9 | * 1.2.beta0 24 Nov 2002 |
10 | * - First version -- complete rewrite of inflate to simplify code, avoid |
11 | * creation of window when not needed, minimize use of window when it is |
12 | * needed, make inffast.c even faster, implement gzip decoding, and to |
13 | * improve code readability and style over the previous zlib inflate code |
14 | * |
15 | * 1.2.beta1 25 Nov 2002 |
16 | * - Use pointers for available input and output checking in inffast.c |
17 | * - Remove input and output counters in inffast.c |
18 | * - Change inffast.c entry and loop from avail_in >= 7 to >= 6 |
19 | * - Remove unnecessary second byte pull from length extra in inffast.c |
20 | * - Unroll direct copy to three copies per loop in inffast.c |
21 | * |
22 | * 1.2.beta2 4 Dec 2002 |
23 | * - Change external routine names to reduce potential conflicts |
24 | * - Correct filename to inffixed.h for fixed tables in inflate.c |
25 | * - Make hbuf[] unsigned char to match parameter type in inflate.c |
26 | * - Change strm->next_out[-state->offset] to *(strm->next_out - state->offset) |
27 | * to avoid negation problem on Alphas (64 bit) in inflate.c |
28 | * |
29 | * 1.2.beta3 22 Dec 2002 |
30 | * - Add comments on state->bits assertion in inffast.c |
31 | * - Add comments on op field in inftrees.h |
32 | * - Fix bug in reuse of allocated window after inflateReset() |
33 | * - Remove bit fields--back to byte structure for speed |
34 | * - Remove distance extra == 0 check in inflate_fast()--only helps for lengths |
35 | * - Change post-increments to pre-increments in inflate_fast(), PPC biased? |
36 | * - Add compile time option, POSTINC, to use post-increments instead (Intel?) |
37 | * - Make MATCH copy in inflate() much faster for when inflate_fast() not used |
38 | * - Use local copies of stream next and avail values, as well as local bit |
39 | * buffer and bit count in inflate()--for speed when inflate_fast() not used |
40 | * |
41 | * 1.2.beta4 1 Jan 2003 |
42 | * - Split ptr - 257 statements in inflate_table() to avoid compiler warnings |
43 | * - Move a comment on output buffer sizes from inffast.c to inflate.c |
44 | * - Add comments in inffast.c to introduce the inflate_fast() routine |
45 | * - Rearrange window copies in inflate_fast() for speed and simplification |
46 | * - Unroll last copy for window match in inflate_fast() |
47 | * - Use local copies of window variables in inflate_fast() for speed |
48 | * - Pull out common wnext == 0 case for speed in inflate_fast() |
49 | * - Make op and len in inflate_fast() unsigned for consistency |
50 | * - Add FAR to lcode and dcode declarations in inflate_fast() |
51 | * - Simplified bad distance check in inflate_fast() |
52 | * - Added inflateBackInit(), inflateBack(), and inflateBackEnd() in new |
53 | * source file infback.c to provide a call-back interface to inflate for |
54 | * programs like gzip and unzip -- uses window as output buffer to avoid |
55 | * window copying |
56 | * |
57 | * 1.2.beta5 1 Jan 2003 |
58 | * - Improved inflateBack() interface to allow the caller to provide initial |
59 | * input in strm. |
60 | * - Fixed stored blocks bug in inflateBack() |
61 | * |
62 | * 1.2.beta6 4 Jan 2003 |
63 | * - Added comments in inffast.c on effectiveness of POSTINC |
64 | * - Typecasting all around to reduce compiler warnings |
65 | * - Changed loops from while (1) or do {} while (1) to for (;;), again to |
66 | * make compilers happy |
67 | * - Changed type of window in inflateBackInit() to unsigned char * |
68 | * |
69 | * 1.2.beta7 27 Jan 2003 |
70 | * - Changed many types to unsigned or unsigned short to avoid warnings |
71 | * - Added inflateCopy() function |
72 | * |
73 | * 1.2.0 9 Mar 2003 |
74 | * - Changed inflateBack() interface to provide separate opaque descriptors |
75 | * for the in() and out() functions |
76 | * - Changed inflateBack() argument and in_func typedef to swap the length |
77 | * and buffer address return values for the input function |
78 | * - Check next_in and next_out for Z_NULL on entry to inflate() |
79 | * |
80 | * The history for versions after 1.2.0 are in ChangeLog in zlib distribution. |
81 | */ |
82 | |
83 | #include "zutil.h" |
84 | #include "inftrees.h" |
85 | #include "inflate.h" |
86 | #include "inffast.h" |
87 | |
88 | #ifdef MAKEFIXED |
89 | # ifndef BUILDFIXED |
90 | # define BUILDFIXED |
91 | # endif |
92 | #endif |
93 | |
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, |
98 | unsigned copy)); |
99 | #ifdef BUILDFIXED |
100 | void makefixed OF((void)); |
101 | #endif |
102 | local unsigned syncsearch OF((unsigned FAR *have, const unsigned char FAR *buf, |
103 | unsigned len)); |
104 | |
105 | local int inflateStateCheck(strm) |
106 | z_streamp strm; |
107 | { |
108 | struct inflate_state FAR *state; |
109 | if (strm == Z_NULL || |
110 | strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) |
111 | return 1; |
112 | state = (struct inflate_state FAR *)strm->state; |
113 | if (state == Z_NULL || state->strm != strm || |
114 | state->mode < HEAD || state->mode > SYNC) |
115 | return 1; |
116 | return 0; |
117 | } |
118 | |
119 | int ZEXPORT inflateResetKeep(strm) |
120 | z_streamp strm; |
121 | { |
122 | struct inflate_state FAR *state; |
123 | |
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; |
127 | strm->msg = Z_NULL; |
128 | if (state->wrap) /* to support ill-conceived Java test suite */ |
129 | strm->adler = state->wrap & 1; |
130 | state->mode = HEAD; |
131 | state->last = 0; |
132 | state->havedict = 0; |
133 | state->flags = -1; |
134 | state->dmax = 32768U; |
135 | state->head = Z_NULL; |
136 | state->hold = 0; |
137 | state->bits = 0; |
138 | state->lencode = state->distcode = state->next = state->codes; |
139 | state->sane = 1; |
140 | state->back = -1; |
141 | Tracev((stderr, "inflate: reset\n" )); |
142 | return Z_OK; |
143 | } |
144 | |
145 | int ZEXPORT inflateReset(strm) |
146 | z_streamp strm; |
147 | { |
148 | struct inflate_state FAR *state; |
149 | |
150 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
151 | state = (struct inflate_state FAR *)strm->state; |
152 | state->wsize = 0; |
153 | state->whave = 0; |
154 | state->wnext = 0; |
155 | return inflateResetKeep(strm); |
156 | } |
157 | |
158 | int ZEXPORT inflateReset2(strm, windowBits) |
159 | z_streamp strm; |
160 | int windowBits; |
161 | { |
162 | int wrap; |
163 | struct inflate_state FAR *state; |
164 | |
165 | /* get the state */ |
166 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
167 | state = (struct inflate_state FAR *)strm->state; |
168 | |
169 | /* extract wrap request from windowBits parameter */ |
170 | if (windowBits < 0) { |
171 | wrap = 0; |
172 | windowBits = -windowBits; |
173 | } |
174 | else { |
175 | wrap = (windowBits >> 4) + 5; |
176 | #ifdef GUNZIP |
177 | if (windowBits < 48) |
178 | windowBits &= 15; |
179 | #endif |
180 | } |
181 | |
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; |
188 | } |
189 | |
190 | /* update state and reset the rest of it */ |
191 | state->wrap = wrap; |
192 | state->wbits = (unsigned)windowBits; |
193 | return inflateReset(strm); |
194 | } |
195 | |
196 | int ZEXPORT inflateInit2_(strm, windowBits, version, stream_size) |
197 | z_streamp strm; |
198 | int windowBits; |
199 | const char *version; |
200 | int stream_size; |
201 | { |
202 | int ret; |
203 | struct inflate_state FAR *state; |
204 | |
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) { |
211 | #ifdef Z_SOLO |
212 | return Z_STREAM_ERROR; |
213 | #else |
214 | strm->zalloc = zcalloc; |
215 | strm->opaque = (voidpf)0; |
216 | #endif |
217 | } |
218 | if (strm->zfree == (free_func)0) |
219 | #ifdef Z_SOLO |
220 | return Z_STREAM_ERROR; |
221 | #else |
222 | strm->zfree = zcfree; |
223 | #endif |
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; |
229 | state->strm = strm; |
230 | state->window = Z_NULL; |
231 | state->mode = HEAD; /* to pass state test in inflateReset2() */ |
232 | ret = inflateReset2(strm, windowBits); |
233 | if (ret != Z_OK) { |
234 | ZFREE(strm, state); |
235 | strm->state = Z_NULL; |
236 | } |
237 | return ret; |
238 | } |
239 | |
240 | int ZEXPORT inflateInit_(strm, version, stream_size) |
241 | z_streamp strm; |
242 | const char *version; |
243 | int stream_size; |
244 | { |
245 | return inflateInit2_(strm, DEF_WBITS, version, stream_size); |
246 | } |
247 | |
248 | int ZEXPORT inflatePrime(strm, bits, value) |
249 | z_streamp strm; |
250 | int bits; |
251 | int value; |
252 | { |
253 | struct inflate_state FAR *state; |
254 | |
255 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
256 | state = (struct inflate_state FAR *)strm->state; |
257 | if (bits < 0) { |
258 | state->hold = 0; |
259 | state->bits = 0; |
260 | return Z_OK; |
261 | } |
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; |
266 | return Z_OK; |
267 | } |
268 | |
269 | /* |
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. |
278 | */ |
279 | local void fixedtables(state) |
280 | struct inflate_state FAR *state; |
281 | { |
282 | #ifdef BUILDFIXED |
283 | static int virgin = 1; |
284 | static code *lenfix, *distfix; |
285 | static code fixed[544]; |
286 | |
287 | /* build fixed huffman tables if first call (may not be thread safe) */ |
288 | if (virgin) { |
289 | unsigned sym, bits; |
290 | static code *next; |
291 | |
292 | /* literal/length table */ |
293 | sym = 0; |
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; |
298 | next = fixed; |
299 | lenfix = next; |
300 | bits = 9; |
301 | inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work); |
302 | |
303 | /* distance table */ |
304 | sym = 0; |
305 | while (sym < 32) state->lens[sym++] = 5; |
306 | distfix = next; |
307 | bits = 5; |
308 | inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work); |
309 | |
310 | /* do this just once */ |
311 | virgin = 0; |
312 | } |
313 | #else /* !BUILDFIXED */ |
314 | # include "inffixed.h" |
315 | #endif /* BUILDFIXED */ |
316 | state->lencode = lenfix; |
317 | state->lenbits = 9; |
318 | state->distcode = distfix; |
319 | state->distbits = 5; |
320 | } |
321 | |
322 | #ifdef MAKEFIXED |
323 | #include <stdio.h> |
324 | |
325 | /* |
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: |
330 | |
331 | void makefixed(void); |
332 | |
333 | int main(void) |
334 | { |
335 | makefixed(); |
336 | return 0; |
337 | } |
338 | |
339 | Then that can be linked with zlib built with MAKEFIXED defined and run: |
340 | |
341 | a.out > inffixed.h |
342 | */ |
343 | void makefixed() |
344 | { |
345 | unsigned low, size; |
346 | struct inflate_state state; |
347 | |
348 | fixedtables(&state); |
349 | puts(" /* inffixed.h -- table for decoding fixed codes" ); |
350 | puts(" * Generated automatically by makefixed()." ); |
351 | puts(" */" ); |
352 | puts("" ); |
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." ); |
356 | puts(" */" ); |
357 | puts("" ); |
358 | size = 1U << 9; |
359 | printf(" static const code lenfix[%u] = {" , size); |
360 | low = 0; |
361 | for (;;) { |
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; |
366 | putchar(','); |
367 | } |
368 | puts("\n };" ); |
369 | size = 1U << 5; |
370 | printf("\n static const code distfix[%u] = {" , size); |
371 | low = 0; |
372 | for (;;) { |
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; |
377 | putchar(','); |
378 | } |
379 | puts("\n };" ); |
380 | } |
381 | #endif /* MAKEFIXED */ |
382 | |
383 | /* |
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 |
389 | is loaded. |
390 | |
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. |
396 | */ |
397 | local int updatewindow(strm, end, copy) |
398 | z_streamp strm; |
399 | const Bytef *end; |
400 | unsigned copy; |
401 | { |
402 | struct inflate_state FAR *state; |
403 | unsigned dist; |
404 | |
405 | state = (struct inflate_state FAR *)strm->state; |
406 | |
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; |
413 | } |
414 | |
415 | /* if window not in use yet, initialize */ |
416 | if (state->wsize == 0) { |
417 | state->wsize = 1U << state->wbits; |
418 | state->wnext = 0; |
419 | state->whave = 0; |
420 | } |
421 | |
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); |
425 | state->wnext = 0; |
426 | state->whave = state->wsize; |
427 | } |
428 | else { |
429 | dist = state->wsize - state->wnext; |
430 | if (dist > copy) dist = copy; |
431 | zmemcpy(state->window + state->wnext, end - copy, dist); |
432 | copy -= dist; |
433 | if (copy) { |
434 | zmemcpy(state->window, end - copy, copy); |
435 | state->wnext = copy; |
436 | state->whave = state->wsize; |
437 | } |
438 | else { |
439 | state->wnext += dist; |
440 | if (state->wnext == state->wsize) state->wnext = 0; |
441 | if (state->whave < state->wsize) state->whave += dist; |
442 | } |
443 | } |
444 | return 0; |
445 | } |
446 | |
447 | /* Macros for inflate(): */ |
448 | |
449 | /* check function to use adler32() for zlib or crc32() for gzip */ |
450 | #ifdef GUNZIP |
451 | # define UPDATE_CHECK(check, buf, len) \ |
452 | (state->flags ? crc32(check, buf, len) : adler32(check, buf, len)) |
453 | #else |
454 | # define UPDATE_CHECK(check, buf, len) adler32(check, buf, len) |
455 | #endif |
456 | |
457 | /* check macros for header crc */ |
458 | #ifdef GUNZIP |
459 | # define CRC2(check, word) \ |
460 | do { \ |
461 | hbuf[0] = (unsigned char)(word); \ |
462 | hbuf[1] = (unsigned char)((word) >> 8); \ |
463 | check = crc32(check, hbuf, 2); \ |
464 | } while (0) |
465 | |
466 | # define CRC4(check, word) \ |
467 | do { \ |
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); \ |
473 | } while (0) |
474 | #endif |
475 | |
476 | /* Load registers with state in inflate() for speed */ |
477 | #define LOAD() \ |
478 | do { \ |
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; \ |
485 | } while (0) |
486 | |
487 | /* Restore state from registers in inflate() */ |
488 | #define RESTORE() \ |
489 | do { \ |
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; \ |
496 | } while (0) |
497 | |
498 | /* Clear the input bit accumulator */ |
499 | #define INITBITS() \ |
500 | do { \ |
501 | hold = 0; \ |
502 | bits = 0; \ |
503 | } while (0) |
504 | |
505 | /* Get a byte of input into the bit accumulator, or return from inflate() |
506 | if there is no input available. */ |
507 | #define PULLBYTE() \ |
508 | do { \ |
509 | if (have == 0) goto inf_leave; \ |
510 | have--; \ |
511 | hold += (unsigned long)(*next++) << bits; \ |
512 | bits += 8; \ |
513 | } while (0) |
514 | |
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) \ |
518 | do { \ |
519 | while (bits < (unsigned)(n)) \ |
520 | PULLBYTE(); \ |
521 | } while (0) |
522 | |
523 | /* Return the low n bits of the bit accumulator (n < 16) */ |
524 | #define BITS(n) \ |
525 | ((unsigned)hold & ((1U << (n)) - 1)) |
526 | |
527 | /* Remove n bits from the bit accumulator */ |
528 | #define DROPBITS(n) \ |
529 | do { \ |
530 | hold >>= (n); \ |
531 | bits -= (unsigned)(n); \ |
532 | } while (0) |
533 | |
534 | /* Remove zero to seven bits as needed to go to a byte boundary */ |
535 | #define BYTEBITS() \ |
536 | do { \ |
537 | hold >>= bits & 7; \ |
538 | bits -= bits & 7; \ |
539 | } while (0) |
540 | |
541 | /* |
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: |
545 | |
546 | for (;;) switch (state) { |
547 | ... |
548 | case STATEn: |
549 | if (not enough input data or output space to make progress) |
550 | return; |
551 | ... make progress ... |
552 | state = STATEm; |
553 | break; |
554 | ... |
555 | } |
556 | |
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 |
562 | is: |
563 | |
564 | NEEDBITS(n); |
565 | ... do something with BITS(n) ... |
566 | DROPBITS(n); |
567 | |
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. |
575 | |
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 |
579 | code, and no more. |
580 | |
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() |
585 | returns: |
586 | |
587 | case STATEw: |
588 | while (want < need) { |
589 | NEEDBITS(n); |
590 | keep[want++] = BITS(n); |
591 | DROPBITS(n); |
592 | } |
593 | state = STATEx; |
594 | case STATEx: |
595 | |
596 | As shown above, if the next state is also the next case, then the break |
597 | is omitted. |
598 | |
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. |
602 | |
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(). |
611 | |
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. |
621 | */ |
622 | |
623 | int ZEXPORT inflate(strm, flush) |
624 | z_streamp strm; |
625 | int flush; |
626 | { |
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 */ |
640 | #ifdef GUNZIP |
641 | unsigned char hbuf[4]; /* buffer for gzip header crc calculation */ |
642 | #endif |
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}; |
645 | |
646 | if (inflateStateCheck(strm) || strm->next_out == Z_NULL || |
647 | (strm->next_in == Z_NULL && strm->avail_in != 0)) |
648 | return Z_STREAM_ERROR; |
649 | |
650 | state = (struct inflate_state FAR *)strm->state; |
651 | if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */ |
652 | LOAD(); |
653 | in = have; |
654 | out = left; |
655 | ret = Z_OK; |
656 | for (;;) |
657 | switch (state->mode) { |
658 | case HEAD: |
659 | if (state->wrap == 0) { |
660 | state->mode = TYPEDO; |
661 | break; |
662 | } |
663 | NEEDBITS(16); |
664 | #ifdef GUNZIP |
665 | if ((state->wrap & 2) && hold == 0x8b1f) { /* gzip header */ |
666 | if (state->wbits == 0) |
667 | state->wbits = 15; |
668 | state->check = crc32(0L, Z_NULL, 0); |
669 | CRC2(state->check, hold); |
670 | INITBITS(); |
671 | state->mode = FLAGS; |
672 | break; |
673 | } |
674 | if (state->head != Z_NULL) |
675 | state->head->done = -1; |
676 | if (!(state->wrap & 1) || /* check if zlib header allowed */ |
677 | #else |
678 | if ( |
679 | #endif |
680 | ((BITS(8) << 8) + (hold >> 8)) % 31) { |
681 | strm->msg = (char *)"incorrect header check" ; |
682 | state->mode = BAD; |
683 | break; |
684 | } |
685 | if (BITS(4) != Z_DEFLATED) { |
686 | strm->msg = (char *)"unknown compression method" ; |
687 | state->mode = BAD; |
688 | break; |
689 | } |
690 | DROPBITS(4); |
691 | len = BITS(4) + 8; |
692 | if (state->wbits == 0) |
693 | state->wbits = len; |
694 | if (len > 15 || len > state->wbits) { |
695 | strm->msg = (char *)"invalid window size" ; |
696 | state->mode = BAD; |
697 | break; |
698 | } |
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; |
704 | INITBITS(); |
705 | break; |
706 | #ifdef GUNZIP |
707 | case FLAGS: |
708 | NEEDBITS(16); |
709 | state->flags = (int)(hold); |
710 | if ((state->flags & 0xff) != Z_DEFLATED) { |
711 | strm->msg = (char *)"unknown compression method" ; |
712 | state->mode = BAD; |
713 | break; |
714 | } |
715 | if (state->flags & 0xe000) { |
716 | strm->msg = (char *)"unknown header flags set" ; |
717 | state->mode = BAD; |
718 | break; |
719 | } |
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); |
724 | INITBITS(); |
725 | state->mode = TIME; |
726 | /* fallthrough */ |
727 | case TIME: |
728 | NEEDBITS(32); |
729 | if (state->head != Z_NULL) |
730 | state->head->time = hold; |
731 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
732 | CRC4(state->check, hold); |
733 | INITBITS(); |
734 | state->mode = OS; |
735 | /* fallthrough */ |
736 | case OS: |
737 | NEEDBITS(16); |
738 | if (state->head != Z_NULL) { |
739 | state->head->xflags = (int)(hold & 0xff); |
740 | state->head->os = (int)(hold >> 8); |
741 | } |
742 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
743 | CRC2(state->check, hold); |
744 | INITBITS(); |
745 | state->mode = EXLEN; |
746 | /* fallthrough */ |
747 | case EXLEN: |
748 | if (state->flags & 0x0400) { |
749 | NEEDBITS(16); |
750 | state->length = (unsigned)(hold); |
751 | if (state->head != Z_NULL) |
752 | state->head->extra_len = (unsigned)hold; |
753 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
754 | CRC2(state->check, hold); |
755 | INITBITS(); |
756 | } |
757 | else if (state->head != Z_NULL) |
758 | state->head->extra = Z_NULL; |
759 | state->mode = EXTRA; |
760 | /* fallthrough */ |
761 | case EXTRA: |
762 | if (state->flags & 0x0400) { |
763 | copy = state->length; |
764 | if (copy > have) copy = have; |
765 | if (copy) { |
766 | if (state->head != Z_NULL && |
767 | state->head->extra != Z_NULL) { |
768 | len = state->head->extra_len - state->length; |
769 | zmemcpy(state->head->extra + len, next, |
770 | len + copy > state->head->extra_max ? |
771 | state->head->extra_max - len : copy); |
772 | } |
773 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
774 | state->check = crc32(state->check, next, copy); |
775 | have -= copy; |
776 | next += copy; |
777 | state->length -= copy; |
778 | } |
779 | if (state->length) goto inf_leave; |
780 | } |
781 | state->length = 0; |
782 | state->mode = NAME; |
783 | /* fallthrough */ |
784 | case NAME: |
785 | if (state->flags & 0x0800) { |
786 | if (have == 0) goto inf_leave; |
787 | copy = 0; |
788 | do { |
789 | len = (unsigned)(next[copy++]); |
790 | if (state->head != Z_NULL && |
791 | state->head->name != Z_NULL && |
792 | state->length < state->head->name_max) |
793 | state->head->name[state->length++] = (Bytef)len; |
794 | } while (len && copy < have); |
795 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
796 | state->check = crc32(state->check, next, copy); |
797 | have -= copy; |
798 | next += copy; |
799 | if (len) goto inf_leave; |
800 | } |
801 | else if (state->head != Z_NULL) |
802 | state->head->name = Z_NULL; |
803 | state->length = 0; |
804 | state->mode = COMMENT; |
805 | /* fallthrough */ |
806 | case COMMENT: |
807 | if (state->flags & 0x1000) { |
808 | if (have == 0) goto inf_leave; |
809 | copy = 0; |
810 | do { |
811 | len = (unsigned)(next[copy++]); |
812 | if (state->head != Z_NULL && |
813 | state->head->comment != Z_NULL && |
814 | state->length < state->head->comm_max) |
815 | state->head->comment[state->length++] = (Bytef)len; |
816 | } while (len && copy < have); |
817 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
818 | state->check = crc32(state->check, next, copy); |
819 | have -= copy; |
820 | next += copy; |
821 | if (len) goto inf_leave; |
822 | } |
823 | else if (state->head != Z_NULL) |
824 | state->head->comment = Z_NULL; |
825 | state->mode = HCRC; |
826 | /* fallthrough */ |
827 | case HCRC: |
828 | if (state->flags & 0x0200) { |
829 | NEEDBITS(16); |
830 | if ((state->wrap & 4) && hold != (state->check & 0xffff)) { |
831 | strm->msg = (char *)"header crc mismatch" ; |
832 | state->mode = BAD; |
833 | break; |
834 | } |
835 | INITBITS(); |
836 | } |
837 | if (state->head != Z_NULL) { |
838 | state->head->hcrc = (int)((state->flags >> 9) & 1); |
839 | state->head->done = 1; |
840 | } |
841 | strm->adler = state->check = crc32(0L, Z_NULL, 0); |
842 | state->mode = TYPE; |
843 | break; |
844 | #endif |
845 | case DICTID: |
846 | NEEDBITS(32); |
847 | strm->adler = state->check = ZSWAP32(hold); |
848 | INITBITS(); |
849 | state->mode = DICT; |
850 | /* fallthrough */ |
851 | case DICT: |
852 | if (state->havedict == 0) { |
853 | RESTORE(); |
854 | return Z_NEED_DICT; |
855 | } |
856 | strm->adler = state->check = adler32(0L, Z_NULL, 0); |
857 | state->mode = TYPE; |
858 | /* fallthrough */ |
859 | case TYPE: |
860 | if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave; |
861 | /* fallthrough */ |
862 | case TYPEDO: |
863 | if (state->last) { |
864 | BYTEBITS(); |
865 | state->mode = CHECK; |
866 | break; |
867 | } |
868 | NEEDBITS(3); |
869 | state->last = BITS(1); |
870 | DROPBITS(1); |
871 | switch (BITS(2)) { |
872 | case 0: /* stored block */ |
873 | Tracev((stderr, "inflate: stored block%s\n" , |
874 | state->last ? " (last)" : "" )); |
875 | state->mode = STORED; |
876 | break; |
877 | case 1: /* fixed block */ |
878 | fixedtables(state); |
879 | Tracev((stderr, "inflate: fixed codes block%s\n" , |
880 | state->last ? " (last)" : "" )); |
881 | state->mode = LEN_; /* decode codes */ |
882 | if (flush == Z_TREES) { |
883 | DROPBITS(2); |
884 | goto inf_leave; |
885 | } |
886 | break; |
887 | case 2: /* dynamic block */ |
888 | Tracev((stderr, "inflate: dynamic codes block%s\n" , |
889 | state->last ? " (last)" : "" )); |
890 | state->mode = TABLE; |
891 | break; |
892 | case 3: |
893 | strm->msg = (char *)"invalid block type" ; |
894 | state->mode = BAD; |
895 | } |
896 | DROPBITS(2); |
897 | break; |
898 | case STORED: |
899 | BYTEBITS(); /* go to byte boundary */ |
900 | NEEDBITS(32); |
901 | if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) { |
902 | strm->msg = (char *)"invalid stored block lengths" ; |
903 | state->mode = BAD; |
904 | break; |
905 | } |
906 | state->length = (unsigned)hold & 0xffff; |
907 | Tracev((stderr, "inflate: stored length %u\n" , |
908 | state->length)); |
909 | INITBITS(); |
910 | state->mode = COPY_; |
911 | if (flush == Z_TREES) goto inf_leave; |
912 | /* fallthrough */ |
913 | case COPY_: |
914 | state->mode = COPY; |
915 | /* fallthrough */ |
916 | case COPY: |
917 | copy = state->length; |
918 | if (copy) { |
919 | if (copy > have) copy = have; |
920 | if (copy > left) copy = left; |
921 | if (copy == 0) goto inf_leave; |
922 | zmemcpy(put, next, copy); |
923 | have -= copy; |
924 | next += copy; |
925 | left -= copy; |
926 | put += copy; |
927 | state->length -= copy; |
928 | break; |
929 | } |
930 | Tracev((stderr, "inflate: stored end\n" )); |
931 | state->mode = TYPE; |
932 | break; |
933 | case TABLE: |
934 | NEEDBITS(14); |
935 | state->nlen = BITS(5) + 257; |
936 | DROPBITS(5); |
937 | state->ndist = BITS(5) + 1; |
938 | DROPBITS(5); |
939 | state->ncode = BITS(4) + 4; |
940 | DROPBITS(4); |
941 | #ifndef PKZIP_BUG_WORKAROUND |
942 | if (state->nlen > 286 || state->ndist > 30) { |
943 | strm->msg = (char *)"too many length or distance symbols" ; |
944 | state->mode = BAD; |
945 | break; |
946 | } |
947 | #endif |
948 | Tracev((stderr, "inflate: table sizes ok\n" )); |
949 | state->have = 0; |
950 | state->mode = LENLENS; |
951 | /* fallthrough */ |
952 | case LENLENS: |
953 | while (state->have < state->ncode) { |
954 | NEEDBITS(3); |
955 | state->lens[order[state->have++]] = (unsigned short)BITS(3); |
956 | DROPBITS(3); |
957 | } |
958 | while (state->have < 19) |
959 | state->lens[order[state->have++]] = 0; |
960 | state->next = state->codes; |
961 | state->lencode = (const code FAR *)(state->next); |
962 | state->lenbits = 7; |
963 | ret = inflate_table(CODES, state->lens, 19, &(state->next), |
964 | &(state->lenbits), state->work); |
965 | if (ret) { |
966 | strm->msg = (char *)"invalid code lengths set" ; |
967 | state->mode = BAD; |
968 | break; |
969 | } |
970 | Tracev((stderr, "inflate: code lengths ok\n" )); |
971 | state->have = 0; |
972 | state->mode = CODELENS; |
973 | /* fallthrough */ |
974 | case CODELENS: |
975 | while (state->have < state->nlen + state->ndist) { |
976 | for (;;) { |
977 | here = state->lencode[BITS(state->lenbits)]; |
978 | if ((unsigned)(here.bits) <= bits) break; |
979 | PULLBYTE(); |
980 | } |
981 | if (here.val < 16) { |
982 | DROPBITS(here.bits); |
983 | state->lens[state->have++] = here.val; |
984 | } |
985 | else { |
986 | if (here.val == 16) { |
987 | NEEDBITS(here.bits + 2); |
988 | DROPBITS(here.bits); |
989 | if (state->have == 0) { |
990 | strm->msg = (char *)"invalid bit length repeat" ; |
991 | state->mode = BAD; |
992 | break; |
993 | } |
994 | len = state->lens[state->have - 1]; |
995 | copy = 3 + BITS(2); |
996 | DROPBITS(2); |
997 | } |
998 | else if (here.val == 17) { |
999 | NEEDBITS(here.bits + 3); |
1000 | DROPBITS(here.bits); |
1001 | len = 0; |
1002 | copy = 3 + BITS(3); |
1003 | DROPBITS(3); |
1004 | } |
1005 | else { |
1006 | NEEDBITS(here.bits + 7); |
1007 | DROPBITS(here.bits); |
1008 | len = 0; |
1009 | copy = 11 + BITS(7); |
1010 | DROPBITS(7); |
1011 | } |
1012 | if (state->have + copy > state->nlen + state->ndist) { |
1013 | strm->msg = (char *)"invalid bit length repeat" ; |
1014 | state->mode = BAD; |
1015 | break; |
1016 | } |
1017 | while (copy--) |
1018 | state->lens[state->have++] = (unsigned short)len; |
1019 | } |
1020 | } |
1021 | |
1022 | /* handle error breaks in while */ |
1023 | if (state->mode == BAD) break; |
1024 | |
1025 | /* check for end-of-block code (better have one) */ |
1026 | if (state->lens[256] == 0) { |
1027 | strm->msg = (char *)"invalid code -- missing end-of-block" ; |
1028 | state->mode = BAD; |
1029 | break; |
1030 | } |
1031 | |
1032 | /* build code tables -- note: do not change the lenbits or distbits |
1033 | values here (9 and 6) without reading the comments in inftrees.h |
1034 | concerning the ENOUGH constants, which depend on those values */ |
1035 | state->next = state->codes; |
1036 | state->lencode = (const code FAR *)(state->next); |
1037 | state->lenbits = 9; |
1038 | ret = inflate_table(LENS, state->lens, state->nlen, &(state->next), |
1039 | &(state->lenbits), state->work); |
1040 | if (ret) { |
1041 | strm->msg = (char *)"invalid literal/lengths set" ; |
1042 | state->mode = BAD; |
1043 | break; |
1044 | } |
1045 | state->distcode = (const code FAR *)(state->next); |
1046 | state->distbits = 6; |
1047 | ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist, |
1048 | &(state->next), &(state->distbits), state->work); |
1049 | if (ret) { |
1050 | strm->msg = (char *)"invalid distances set" ; |
1051 | state->mode = BAD; |
1052 | break; |
1053 | } |
1054 | Tracev((stderr, "inflate: codes ok\n" )); |
1055 | state->mode = LEN_; |
1056 | if (flush == Z_TREES) goto inf_leave; |
1057 | /* fallthrough */ |
1058 | case LEN_: |
1059 | state->mode = LEN; |
1060 | /* fallthrough */ |
1061 | case LEN: |
1062 | if (have >= 6 && left >= 258) { |
1063 | RESTORE(); |
1064 | inflate_fast(strm, out); |
1065 | LOAD(); |
1066 | if (state->mode == TYPE) |
1067 | state->back = -1; |
1068 | break; |
1069 | } |
1070 | state->back = 0; |
1071 | for (;;) { |
1072 | here = state->lencode[BITS(state->lenbits)]; |
1073 | if ((unsigned)(here.bits) <= bits) break; |
1074 | PULLBYTE(); |
1075 | } |
1076 | if (here.op && (here.op & 0xf0) == 0) { |
1077 | last = here; |
1078 | for (;;) { |
1079 | here = state->lencode[last.val + |
1080 | (BITS(last.bits + last.op) >> last.bits)]; |
1081 | if ((unsigned)(last.bits + here.bits) <= bits) break; |
1082 | PULLBYTE(); |
1083 | } |
1084 | DROPBITS(last.bits); |
1085 | state->back += last.bits; |
1086 | } |
1087 | DROPBITS(here.bits); |
1088 | state->back += here.bits; |
1089 | state->length = (unsigned)here.val; |
1090 | if ((int)(here.op) == 0) { |
1091 | Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ? |
1092 | "inflate: literal '%c'\n" : |
1093 | "inflate: literal 0x%02x\n" , here.val)); |
1094 | state->mode = LIT; |
1095 | break; |
1096 | } |
1097 | if (here.op & 32) { |
1098 | Tracevv((stderr, "inflate: end of block\n" )); |
1099 | state->back = -1; |
1100 | state->mode = TYPE; |
1101 | break; |
1102 | } |
1103 | if (here.op & 64) { |
1104 | strm->msg = (char *)"invalid literal/length code" ; |
1105 | state->mode = BAD; |
1106 | break; |
1107 | } |
1108 | state->extra = (unsigned)(here.op) & 15; |
1109 | state->mode = LENEXT; |
1110 | /* fallthrough */ |
1111 | case LENEXT: |
1112 | if (state->extra) { |
1113 | NEEDBITS(state->extra); |
1114 | state->length += BITS(state->extra); |
1115 | DROPBITS(state->extra); |
1116 | state->back += state->extra; |
1117 | } |
1118 | Tracevv((stderr, "inflate: length %u\n" , state->length)); |
1119 | state->was = state->length; |
1120 | state->mode = DIST; |
1121 | /* fallthrough */ |
1122 | case DIST: |
1123 | for (;;) { |
1124 | here = state->distcode[BITS(state->distbits)]; |
1125 | if ((unsigned)(here.bits) <= bits) break; |
1126 | PULLBYTE(); |
1127 | } |
1128 | if ((here.op & 0xf0) == 0) { |
1129 | last = here; |
1130 | for (;;) { |
1131 | here = state->distcode[last.val + |
1132 | (BITS(last.bits + last.op) >> last.bits)]; |
1133 | if ((unsigned)(last.bits + here.bits) <= bits) break; |
1134 | PULLBYTE(); |
1135 | } |
1136 | DROPBITS(last.bits); |
1137 | state->back += last.bits; |
1138 | } |
1139 | DROPBITS(here.bits); |
1140 | state->back += here.bits; |
1141 | if (here.op & 64) { |
1142 | strm->msg = (char *)"invalid distance code" ; |
1143 | state->mode = BAD; |
1144 | break; |
1145 | } |
1146 | state->offset = (unsigned)here.val; |
1147 | state->extra = (unsigned)(here.op) & 15; |
1148 | state->mode = DISTEXT; |
1149 | /* fallthrough */ |
1150 | case DISTEXT: |
1151 | if (state->extra) { |
1152 | NEEDBITS(state->extra); |
1153 | state->offset += BITS(state->extra); |
1154 | DROPBITS(state->extra); |
1155 | state->back += state->extra; |
1156 | } |
1157 | #ifdef INFLATE_STRICT |
1158 | if (state->offset > state->dmax) { |
1159 | strm->msg = (char *)"invalid distance too far back" ; |
1160 | state->mode = BAD; |
1161 | break; |
1162 | } |
1163 | #endif |
1164 | Tracevv((stderr, "inflate: distance %u\n" , state->offset)); |
1165 | state->mode = MATCH; |
1166 | /* fallthrough */ |
1167 | case MATCH: |
1168 | if (left == 0) goto inf_leave; |
1169 | copy = out - left; |
1170 | if (state->offset > copy) { /* copy from window */ |
1171 | copy = state->offset - copy; |
1172 | if (copy > state->whave) { |
1173 | if (state->sane) { |
1174 | strm->msg = (char *)"invalid distance too far back" ; |
1175 | state->mode = BAD; |
1176 | break; |
1177 | } |
1178 | #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR |
1179 | Trace((stderr, "inflate.c too far\n" )); |
1180 | copy -= state->whave; |
1181 | if (copy > state->length) copy = state->length; |
1182 | if (copy > left) copy = left; |
1183 | left -= copy; |
1184 | state->length -= copy; |
1185 | do { |
1186 | *put++ = 0; |
1187 | } while (--copy); |
1188 | if (state->length == 0) state->mode = LEN; |
1189 | break; |
1190 | #endif |
1191 | } |
1192 | if (copy > state->wnext) { |
1193 | copy -= state->wnext; |
1194 | from = state->window + (state->wsize - copy); |
1195 | } |
1196 | else |
1197 | from = state->window + (state->wnext - copy); |
1198 | if (copy > state->length) copy = state->length; |
1199 | } |
1200 | else { /* copy from output */ |
1201 | from = put - state->offset; |
1202 | copy = state->length; |
1203 | } |
1204 | if (copy > left) copy = left; |
1205 | left -= copy; |
1206 | state->length -= copy; |
1207 | do { |
1208 | *put++ = *from++; |
1209 | } while (--copy); |
1210 | if (state->length == 0) state->mode = LEN; |
1211 | break; |
1212 | case LIT: |
1213 | if (left == 0) goto inf_leave; |
1214 | *put++ = (unsigned char)(state->length); |
1215 | left--; |
1216 | state->mode = LEN; |
1217 | break; |
1218 | case CHECK: |
1219 | if (state->wrap) { |
1220 | NEEDBITS(32); |
1221 | out -= left; |
1222 | strm->total_out += out; |
1223 | state->total += out; |
1224 | if ((state->wrap & 4) && out) |
1225 | strm->adler = state->check = |
1226 | UPDATE_CHECK(state->check, put - out, out); |
1227 | out = left; |
1228 | if ((state->wrap & 4) && ( |
1229 | #ifdef GUNZIP |
1230 | state->flags ? hold : |
1231 | #endif |
1232 | ZSWAP32(hold)) != state->check) { |
1233 | strm->msg = (char *)"incorrect data check" ; |
1234 | state->mode = BAD; |
1235 | break; |
1236 | } |
1237 | INITBITS(); |
1238 | Tracev((stderr, "inflate: check matches trailer\n" )); |
1239 | } |
1240 | #ifdef GUNZIP |
1241 | state->mode = LENGTH; |
1242 | /* fallthrough */ |
1243 | case LENGTH: |
1244 | if (state->wrap && state->flags) { |
1245 | NEEDBITS(32); |
1246 | if ((state->wrap & 4) && hold != (state->total & 0xffffffff)) { |
1247 | strm->msg = (char *)"incorrect length check" ; |
1248 | state->mode = BAD; |
1249 | break; |
1250 | } |
1251 | INITBITS(); |
1252 | Tracev((stderr, "inflate: length matches trailer\n" )); |
1253 | } |
1254 | #endif |
1255 | state->mode = DONE; |
1256 | /* fallthrough */ |
1257 | case DONE: |
1258 | ret = Z_STREAM_END; |
1259 | goto inf_leave; |
1260 | case BAD: |
1261 | ret = Z_DATA_ERROR; |
1262 | goto inf_leave; |
1263 | case MEM: |
1264 | return Z_MEM_ERROR; |
1265 | case SYNC: |
1266 | /* fallthrough */ |
1267 | default: |
1268 | return Z_STREAM_ERROR; |
1269 | } |
1270 | |
1271 | /* |
1272 | Return from inflate(), updating the total counts and the check value. |
1273 | If there was no progress during the inflate() call, return a buffer |
1274 | error. Call updatewindow() to create and/or update the window state. |
1275 | Note: a memory error from inflate() is non-recoverable. |
1276 | */ |
1277 | inf_leave: |
1278 | RESTORE(); |
1279 | if (state->wsize || (out != strm->avail_out && state->mode < BAD && |
1280 | (state->mode < CHECK || flush != Z_FINISH))) |
1281 | if (updatewindow(strm, strm->next_out, out - strm->avail_out)) { |
1282 | state->mode = MEM; |
1283 | return Z_MEM_ERROR; |
1284 | } |
1285 | in -= strm->avail_in; |
1286 | out -= strm->avail_out; |
1287 | strm->total_in += in; |
1288 | strm->total_out += out; |
1289 | state->total += out; |
1290 | if ((state->wrap & 4) && out) |
1291 | strm->adler = state->check = |
1292 | UPDATE_CHECK(state->check, strm->next_out - out, out); |
1293 | strm->data_type = (int)state->bits + (state->last ? 64 : 0) + |
1294 | (state->mode == TYPE ? 128 : 0) + |
1295 | (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0); |
1296 | if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK) |
1297 | ret = Z_BUF_ERROR; |
1298 | return ret; |
1299 | } |
1300 | |
1301 | int ZEXPORT inflateEnd(strm) |
1302 | z_streamp strm; |
1303 | { |
1304 | struct inflate_state FAR *state; |
1305 | if (inflateStateCheck(strm)) |
1306 | return Z_STREAM_ERROR; |
1307 | state = (struct inflate_state FAR *)strm->state; |
1308 | if (state->window != Z_NULL) ZFREE(strm, state->window); |
1309 | ZFREE(strm, strm->state); |
1310 | strm->state = Z_NULL; |
1311 | Tracev((stderr, "inflate: end\n" )); |
1312 | return Z_OK; |
1313 | } |
1314 | |
1315 | int ZEXPORT inflateGetDictionary(strm, dictionary, dictLength) |
1316 | z_streamp strm; |
1317 | Bytef *dictionary; |
1318 | uInt *dictLength; |
1319 | { |
1320 | struct inflate_state FAR *state; |
1321 | |
1322 | /* check state */ |
1323 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
1324 | state = (struct inflate_state FAR *)strm->state; |
1325 | |
1326 | /* copy dictionary */ |
1327 | if (state->whave && dictionary != Z_NULL) { |
1328 | zmemcpy(dictionary, state->window + state->wnext, |
1329 | state->whave - state->wnext); |
1330 | zmemcpy(dictionary + state->whave - state->wnext, |
1331 | state->window, state->wnext); |
1332 | } |
1333 | if (dictLength != Z_NULL) |
1334 | *dictLength = state->whave; |
1335 | return Z_OK; |
1336 | } |
1337 | |
1338 | int ZEXPORT inflateSetDictionary(strm, dictionary, dictLength) |
1339 | z_streamp strm; |
1340 | const Bytef *dictionary; |
1341 | uInt dictLength; |
1342 | { |
1343 | struct inflate_state FAR *state; |
1344 | unsigned long dictid; |
1345 | int ret; |
1346 | |
1347 | /* check state */ |
1348 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
1349 | state = (struct inflate_state FAR *)strm->state; |
1350 | if (state->wrap != 0 && state->mode != DICT) |
1351 | return Z_STREAM_ERROR; |
1352 | |
1353 | /* check for correct dictionary identifier */ |
1354 | if (state->mode == DICT) { |
1355 | dictid = adler32(0L, Z_NULL, 0); |
1356 | dictid = adler32(dictid, dictionary, dictLength); |
1357 | if (dictid != state->check) |
1358 | return Z_DATA_ERROR; |
1359 | } |
1360 | |
1361 | /* copy dictionary to window using updatewindow(), which will amend the |
1362 | existing dictionary if appropriate */ |
1363 | ret = updatewindow(strm, dictionary + dictLength, dictLength); |
1364 | if (ret) { |
1365 | state->mode = MEM; |
1366 | return Z_MEM_ERROR; |
1367 | } |
1368 | state->havedict = 1; |
1369 | Tracev((stderr, "inflate: dictionary set\n" )); |
1370 | return Z_OK; |
1371 | } |
1372 | |
1373 | int ZEXPORT (strm, head) |
1374 | z_streamp strm; |
1375 | gz_headerp head; |
1376 | { |
1377 | struct inflate_state FAR *state; |
1378 | |
1379 | /* check state */ |
1380 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
1381 | state = (struct inflate_state FAR *)strm->state; |
1382 | if ((state->wrap & 2) == 0) return Z_STREAM_ERROR; |
1383 | |
1384 | /* save header structure */ |
1385 | state->head = head; |
1386 | head->done = 0; |
1387 | return Z_OK; |
1388 | } |
1389 | |
1390 | /* |
1391 | Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff. Return when found |
1392 | or when out of input. When called, *have is the number of pattern bytes |
1393 | found in order so far, in 0..3. On return *have is updated to the new |
1394 | state. If on return *have equals four, then the pattern was found and the |
1395 | return value is how many bytes were read including the last byte of the |
1396 | pattern. If *have is less than four, then the pattern has not been found |
1397 | yet and the return value is len. In the latter case, syncsearch() can be |
1398 | called again with more data and the *have state. *have is initialized to |
1399 | zero for the first call. |
1400 | */ |
1401 | local unsigned syncsearch(have, buf, len) |
1402 | unsigned FAR *have; |
1403 | const unsigned char FAR *buf; |
1404 | unsigned len; |
1405 | { |
1406 | unsigned got; |
1407 | unsigned next; |
1408 | |
1409 | got = *have; |
1410 | next = 0; |
1411 | while (next < len && got < 4) { |
1412 | if ((int)(buf[next]) == (got < 2 ? 0 : 0xff)) |
1413 | got++; |
1414 | else if (buf[next]) |
1415 | got = 0; |
1416 | else |
1417 | got = 4 - got; |
1418 | next++; |
1419 | } |
1420 | *have = got; |
1421 | return next; |
1422 | } |
1423 | |
1424 | int ZEXPORT inflateSync(strm) |
1425 | z_streamp strm; |
1426 | { |
1427 | unsigned len; /* number of bytes to look at or looked at */ |
1428 | int flags; /* temporary to save header status */ |
1429 | unsigned long in, out; /* temporary to save total_in and total_out */ |
1430 | unsigned char buf[4]; /* to restore bit buffer to byte string */ |
1431 | struct inflate_state FAR *state; |
1432 | |
1433 | /* check parameters */ |
1434 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
1435 | state = (struct inflate_state FAR *)strm->state; |
1436 | if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR; |
1437 | |
1438 | /* if first time, start search in bit buffer */ |
1439 | if (state->mode != SYNC) { |
1440 | state->mode = SYNC; |
1441 | state->hold <<= state->bits & 7; |
1442 | state->bits -= state->bits & 7; |
1443 | len = 0; |
1444 | while (state->bits >= 8) { |
1445 | buf[len++] = (unsigned char)(state->hold); |
1446 | state->hold >>= 8; |
1447 | state->bits -= 8; |
1448 | } |
1449 | state->have = 0; |
1450 | syncsearch(&(state->have), buf, len); |
1451 | } |
1452 | |
1453 | /* search available input */ |
1454 | len = syncsearch(&(state->have), strm->next_in, strm->avail_in); |
1455 | strm->avail_in -= len; |
1456 | strm->next_in += len; |
1457 | strm->total_in += len; |
1458 | |
1459 | /* return no joy or set up to restart inflate() on a new block */ |
1460 | if (state->have != 4) return Z_DATA_ERROR; |
1461 | if (state->flags == -1) |
1462 | state->wrap = 0; /* if no header yet, treat as raw */ |
1463 | else |
1464 | state->wrap &= ~4; /* no point in computing a check value now */ |
1465 | flags = state->flags; |
1466 | in = strm->total_in; out = strm->total_out; |
1467 | inflateReset(strm); |
1468 | strm->total_in = in; strm->total_out = out; |
1469 | state->flags = flags; |
1470 | state->mode = TYPE; |
1471 | return Z_OK; |
1472 | } |
1473 | |
1474 | /* |
1475 | Returns true if inflate is currently at the end of a block generated by |
1476 | Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP |
1477 | implementation to provide an additional safety check. PPP uses |
1478 | Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored |
1479 | block. When decompressing, PPP checks that at the end of input packet, |
1480 | inflate is waiting for these length bytes. |
1481 | */ |
1482 | int ZEXPORT inflateSyncPoint(strm) |
1483 | z_streamp strm; |
1484 | { |
1485 | struct inflate_state FAR *state; |
1486 | |
1487 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
1488 | state = (struct inflate_state FAR *)strm->state; |
1489 | return state->mode == STORED && state->bits == 0; |
1490 | } |
1491 | |
1492 | int ZEXPORT inflateCopy(dest, source) |
1493 | z_streamp dest; |
1494 | z_streamp source; |
1495 | { |
1496 | struct inflate_state FAR *state; |
1497 | struct inflate_state FAR *copy; |
1498 | unsigned char FAR *window; |
1499 | unsigned wsize; |
1500 | |
1501 | /* check input */ |
1502 | if (inflateStateCheck(source) || dest == Z_NULL) |
1503 | return Z_STREAM_ERROR; |
1504 | state = (struct inflate_state FAR *)source->state; |
1505 | |
1506 | /* allocate space */ |
1507 | copy = (struct inflate_state FAR *) |
1508 | ZALLOC(source, 1, sizeof(struct inflate_state)); |
1509 | if (copy == Z_NULL) return Z_MEM_ERROR; |
1510 | window = Z_NULL; |
1511 | if (state->window != Z_NULL) { |
1512 | window = (unsigned char FAR *) |
1513 | ZALLOC(source, 1U << state->wbits, sizeof(unsigned char)); |
1514 | if (window == Z_NULL) { |
1515 | ZFREE(source, copy); |
1516 | return Z_MEM_ERROR; |
1517 | } |
1518 | } |
1519 | |
1520 | /* copy state */ |
1521 | zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream)); |
1522 | zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state)); |
1523 | copy->strm = dest; |
1524 | if (state->lencode >= state->codes && |
1525 | state->lencode <= state->codes + ENOUGH - 1) { |
1526 | copy->lencode = copy->codes + (state->lencode - state->codes); |
1527 | copy->distcode = copy->codes + (state->distcode - state->codes); |
1528 | } |
1529 | copy->next = copy->codes + (state->next - state->codes); |
1530 | if (window != Z_NULL) { |
1531 | wsize = 1U << state->wbits; |
1532 | zmemcpy(window, state->window, wsize); |
1533 | } |
1534 | copy->window = window; |
1535 | dest->state = (struct internal_state FAR *)copy; |
1536 | return Z_OK; |
1537 | } |
1538 | |
1539 | int ZEXPORT inflateUndermine(strm, subvert) |
1540 | z_streamp strm; |
1541 | int subvert; |
1542 | { |
1543 | struct inflate_state FAR *state; |
1544 | |
1545 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
1546 | state = (struct inflate_state FAR *)strm->state; |
1547 | #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR |
1548 | state->sane = !subvert; |
1549 | return Z_OK; |
1550 | #else |
1551 | (void)subvert; |
1552 | state->sane = 1; |
1553 | return Z_DATA_ERROR; |
1554 | #endif |
1555 | } |
1556 | |
1557 | int ZEXPORT inflateValidate(strm, check) |
1558 | z_streamp strm; |
1559 | int check; |
1560 | { |
1561 | struct inflate_state FAR *state; |
1562 | |
1563 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
1564 | state = (struct inflate_state FAR *)strm->state; |
1565 | if (check && state->wrap) |
1566 | state->wrap |= 4; |
1567 | else |
1568 | state->wrap &= ~4; |
1569 | return Z_OK; |
1570 | } |
1571 | |
1572 | long ZEXPORT inflateMark(strm) |
1573 | z_streamp strm; |
1574 | { |
1575 | struct inflate_state FAR *state; |
1576 | |
1577 | if (inflateStateCheck(strm)) |
1578 | return -(1L << 16); |
1579 | state = (struct inflate_state FAR *)strm->state; |
1580 | return (long)(((unsigned long)((long)state->back)) << 16) + |
1581 | (state->mode == COPY ? state->length : |
1582 | (state->mode == MATCH ? state->was - state->length : 0)); |
1583 | } |
1584 | |
1585 | unsigned long ZEXPORT inflateCodesUsed(strm) |
1586 | z_streamp strm; |
1587 | { |
1588 | struct inflate_state FAR *state; |
1589 | if (inflateStateCheck(strm)) return (unsigned long)-1; |
1590 | state = (struct inflate_state FAR *)strm->state; |
1591 | return (unsigned long)(state->next - state->codes); |
1592 | } |
1593 | |