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7795edd6 JAS |
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 | |
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 | #ifndef Z_TREES | |
95 | #define Z_TREES 6 | |
96 | #endif | |
97 | ||
98 | /* function prototypes */ | |
99 | int ZEXPORT inflateReset2(z_streamp strm, int windowBits); | |
100 | local void fixedtables OF((struct inflate_state FAR *state)); | |
101 | local int updatewindow OF((z_streamp strm, const unsigned char FAR *end, | |
102 | unsigned copy)); | |
103 | #ifdef BUILDFIXED | |
104 | void makefixed OF((void)); | |
105 | #endif | |
106 | local unsigned syncsearch OF((unsigned FAR *have, const unsigned char FAR *buf, | |
107 | unsigned len)); | |
108 | ||
109 | long ZEXPORT inflateMark(z_streamp strm); | |
110 | ||
111 | int ZEXPORT inflateResetKeep(z_streamp strm); | |
112 | ||
113 | int ZEXPORT inflateUndermine(z_streamp strm, int subvert); | |
114 | ||
115 | int ZEXPORT inflateGetDictionary(z_streamp strm, Bytef *dictionary, uInt *dictLength); | |
116 | ||
117 | int ZEXPORT inflateResetKeep(z_streamp strm) | |
118 | { | |
119 | struct inflate_state FAR *state; | |
120 | ||
121 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
122 | state = (struct inflate_state FAR *)strm->state; | |
123 | strm->total_in = strm->total_out = state->total = 0; | |
124 | strm->msg = Z_NULL; | |
125 | if (state->wrap) /* to support ill-conceived Java test suite */ | |
126 | strm->adler = state->wrap & 1; | |
127 | state->mode = HEAD; | |
128 | state->last = 0; | |
129 | state->havedict = 0; | |
130 | state->dmax = 32768U; | |
131 | state->head = Z_NULL; | |
132 | state->hold = 0; | |
133 | state->bits = 0; | |
134 | state->lencode = state->distcode = state->next = state->codes; | |
135 | state->sane = 1; | |
136 | state->back = -1; | |
137 | Tracev((stderr, "inflate: reset\n")); | |
138 | return Z_OK; | |
139 | } | |
140 | ||
141 | int ZEXPORT inflateReset(z_streamp strm) | |
142 | { | |
143 | struct inflate_state FAR *state; | |
144 | ||
145 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
146 | state = (struct inflate_state FAR *)strm->state; | |
147 | state->wsize = 0; | |
148 | state->whave = 0; | |
149 | state->wnext = 0; | |
150 | return inflateResetKeep(strm); | |
151 | } | |
152 | ||
153 | int ZEXPORT inflateReset2(z_streamp strm, int windowBits) | |
154 | { | |
155 | int wrap; | |
156 | struct inflate_state FAR *state = NULL; | |
157 | ||
158 | /* get the state */ | |
159 | if (strm == Z_NULL || strm->state == Z_NULL) | |
160 | return Z_STREAM_ERROR; | |
161 | state = (struct inflate_state FAR *)strm->state; | |
162 | ||
163 | /* extract wrap request from windowBits parameter */ | |
164 | if (windowBits < 0) { | |
165 | wrap = 0; | |
166 | windowBits = -windowBits; | |
167 | } | |
168 | else { | |
169 | wrap = (windowBits >> 4) + 1; | |
170 | #ifdef GUNZIP | |
171 | if (windowBits < 48) | |
172 | windowBits &= 15; | |
173 | #endif | |
174 | } | |
175 | ||
176 | /* set number of window bits, free window if different */ | |
177 | if (windowBits && (windowBits < 8 || windowBits > 15)) | |
178 | return Z_STREAM_ERROR; | |
179 | if (state->window != Z_NULL && state->wbits != (unsigned)windowBits) { | |
180 | ZFREE(strm, state->window); | |
181 | state->window = Z_NULL; | |
182 | } | |
183 | ||
184 | /* update state and reset the rest of it */ | |
185 | state->wrap = wrap; | |
186 | state->wbits = (unsigned)windowBits; | |
187 | return inflateReset(strm); | |
188 | } | |
189 | ||
190 | int ZEXPORT inflateInit2_(z_streamp strm, int windowBits, const char *version, int stream_size) | |
191 | { | |
192 | int ret; | |
193 | struct inflate_state FAR *state; | |
194 | ||
195 | if (version == Z_NULL || version[0] != ZLIB_VERSION[0] || | |
196 | stream_size != (int)(sizeof(z_stream))) | |
197 | return Z_VERSION_ERROR; | |
198 | if (strm == Z_NULL) return Z_STREAM_ERROR; | |
199 | strm->msg = Z_NULL; /* in case we return an error */ | |
200 | if (strm->zalloc == (alloc_func)0) { | |
201 | #ifdef Z_SOLO | |
202 | return Z_STREAM_ERROR; | |
203 | #else | |
204 | strm->zalloc = zcalloc; | |
205 | strm->opaque = (voidpf)0; | |
206 | #endif | |
207 | } | |
208 | if (strm->zfree == Z_NULL) | |
209 | #ifdef Z_SOLO | |
210 | return Z_STREAM_ERROR; | |
211 | #else | |
212 | strm->zfree = zcfree; | |
213 | #endif | |
214 | state = (struct inflate_state FAR *) | |
215 | ZALLOC(strm, 1, sizeof(struct inflate_state)); | |
216 | if (state == Z_NULL) return Z_MEM_ERROR; | |
217 | Tracev((stderr, "inflate: allocated\n")); | |
218 | strm->state = (struct internal_state FAR *)state; | |
219 | state->window = Z_NULL; | |
220 | ret = inflateReset2(strm, windowBits); | |
221 | if (ret != Z_OK) { | |
222 | ZFREE(strm, state); | |
223 | strm->state = Z_NULL; | |
224 | } | |
225 | return ret; | |
226 | } | |
227 | ||
228 | int ZEXPORT inflateInit_(z_streamp strm, const char *version, int stream_size) | |
229 | { | |
230 | return inflateInit2_(strm, DEF_WBITS, version, stream_size); | |
231 | } | |
232 | ||
233 | int ZEXPORT inflatePrime(z_streamp strm, int bits, int value) | |
234 | { | |
235 | struct inflate_state FAR *state; | |
236 | ||
237 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
238 | state = (struct inflate_state FAR *)strm->state; | |
239 | if (bits < 0) { | |
240 | state->hold = 0; | |
241 | state->bits = 0; | |
242 | return Z_OK; | |
243 | } | |
244 | if (bits > 16 || state->bits + bits > 32) return Z_STREAM_ERROR; | |
245 | value &= (1L << bits) - 1; | |
246 | state->hold += value << state->bits; | |
247 | state->bits += bits; | |
248 | return Z_OK; | |
249 | } | |
250 | ||
251 | /* | |
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. | |
260 | */ | |
261 | local void fixedtables(struct inflate_state FAR *state) | |
262 | { | |
263 | #ifdef BUILDFIXED | |
264 | static int virgin = 1; | |
265 | static code *lenfix, *distfix; | |
266 | static code fixed[544]; | |
267 | ||
268 | /* build fixed huffman tables if first call (may not be thread safe) */ | |
269 | if (virgin) { | |
270 | unsigned sym, bits; | |
271 | static code *next; | |
272 | ||
273 | /* literal/length table */ | |
274 | sym = 0; | |
275 | while (sym < 144) state->lens[sym++] = 8; | |
276 | while (sym < 256) state->lens[sym++] = 9; | |
277 | while (sym < 280) state->lens[sym++] = 7; | |
278 | while (sym < 288) state->lens[sym++] = 8; | |
279 | next = fixed; | |
280 | lenfix = next; | |
281 | bits = 9; | |
282 | inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work); | |
283 | ||
284 | /* distance table */ | |
285 | sym = 0; | |
286 | while (sym < 32) state->lens[sym++] = 5; | |
287 | distfix = next; | |
288 | bits = 5; | |
289 | inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work); | |
290 | ||
291 | /* do this just once */ | |
292 | virgin = 0; | |
293 | } | |
294 | #else /* !BUILDFIXED */ | |
295 | # include "inffixed.h" | |
296 | #endif /* BUILDFIXED */ | |
297 | state->lencode = lenfix; | |
298 | state->lenbits = 9; | |
299 | state->distcode = distfix; | |
300 | state->distbits = 5; | |
301 | } | |
302 | ||
303 | #ifdef MAKEFIXED | |
304 | #include <stdio.h> | |
305 | ||
306 | /* | |
307 | Write out the inffixed.h that is #include'd above. Defining MAKEFIXED also | |
308 | defines BUILDFIXED, so the tables are built on the fly. makefixed() writes | |
309 | those tables to stdout, which would be piped to inffixed.h. A small program | |
310 | can simply call makefixed to do this: | |
311 | ||
312 | void makefixed(void); | |
313 | ||
314 | int main(void) | |
315 | { | |
316 | makefixed(); | |
317 | return 0; | |
318 | } | |
319 | ||
320 | Then that can be linked with zlib built with MAKEFIXED defined and run: | |
321 | ||
322 | a.out > inffixed.h | |
323 | */ | |
324 | void makefixed(void) | |
325 | { | |
326 | unsigned low, size; | |
327 | struct inflate_state state; | |
328 | ||
329 | fixedtables(&state); | |
330 | puts(" /* inffixed.h -- table for decoding fixed codes"); | |
331 | puts(" * Generated automatically by makefixed()."); | |
332 | puts(" */"); | |
333 | puts(""); | |
334 | puts(" /* WARNING: this file should *not* be used by applications."); | |
335 | puts(" It is part of the implementation of this library and is"); | |
336 | puts(" subject to change. Applications should only use zlib.h."); | |
337 | puts(" */"); | |
338 | puts(""); | |
339 | size = 1U << 9; | |
340 | printf(" static const code lenfix[%u] = {", size); | |
341 | low = 0; | |
342 | for (;;) { | |
343 | if ((low % 7) == 0) printf("\n "); | |
344 | printf("{%u,%u,%d}", (low & 127) == 99 ? 64 : state.lencode[low].op, | |
345 | state.lencode[low].bits, state.lencode[low].val); | |
346 | if (++low == size) break; | |
347 | putchar(','); | |
348 | } | |
349 | puts("\n };"); | |
350 | size = 1U << 5; | |
351 | printf("\n static const code distfix[%u] = {", size); | |
352 | low = 0; | |
353 | for (;;) { | |
354 | if ((low % 6) == 0) printf("\n "); | |
355 | printf("{%u,%u,%d}", state.distcode[low].op, state.distcode[low].bits, | |
356 | state.distcode[low].val); | |
357 | if (++low == size) break; | |
358 | putchar(','); | |
359 | } | |
360 | puts("\n };"); | |
361 | } | |
362 | #endif /* MAKEFIXED */ | |
363 | ||
364 | /* | |
365 | Update the window with the last wsize (normally 32K) bytes written before | |
366 | returning. If window does not exist yet, create it. This is only called | |
367 | when a window is already in use, or when output has been written during this | |
368 | inflate call, but the end of the deflate stream has not been reached yet. | |
369 | It is also called to create a window for dictionary data when a dictionary | |
370 | is loaded. | |
371 | ||
372 | Providing output buffers larger than 32K to inflate() should provide a speed | |
373 | advantage, since only the last 32K of output is copied to the sliding window | |
374 | upon return from inflate(), and since all distances after the first 32K of | |
375 | output will fall in the output data, making match copies simpler and faster. | |
376 | The advantage may be dependent on the size of the processor's data caches. | |
377 | */ | |
378 | local int updatewindow(z_streamp strm, const Bytef *end, unsigned copy) | |
379 | { | |
380 | struct inflate_state FAR *state; | |
381 | unsigned dist; | |
382 | ||
383 | state = (struct inflate_state FAR *)strm->state; | |
384 | ||
385 | /* if it hasn't been done already, allocate space for the window */ | |
386 | if (state->window == Z_NULL) { | |
387 | state->window = (unsigned char FAR *) | |
388 | ZALLOC(strm, 1U << state->wbits, | |
389 | sizeof(unsigned char)); | |
390 | if (state->window == Z_NULL) return 1; | |
391 | } | |
392 | ||
393 | /* if window not in use yet, initialize */ | |
394 | if (state->wsize == 0) { | |
395 | state->wsize = 1U << state->wbits; | |
396 | state->wnext = 0; | |
397 | state->whave = 0; | |
398 | } | |
399 | ||
400 | /* copy state->wsize or less output bytes into the circular window */ | |
401 | if (copy >= state->wsize) { | |
402 | zmemcpy(state->window, end - state->wsize, state->wsize); | |
403 | state->wnext = 0; | |
404 | state->whave = state->wsize; | |
405 | } | |
406 | else { | |
407 | dist = state->wsize - state->wnext; | |
408 | if (dist > copy) dist = copy; | |
409 | zmemcpy(state->window + state->wnext, end - copy, dist); | |
410 | copy -= dist; | |
411 | if (copy) { | |
412 | zmemcpy(state->window, end - copy, copy); | |
413 | state->wnext = copy; | |
414 | state->whave = state->wsize; | |
415 | } | |
416 | else { | |
417 | state->wnext += dist; | |
418 | if (state->wnext == state->wsize) state->wnext = 0; | |
419 | if (state->whave < state->wsize) state->whave += dist; | |
420 | } | |
421 | } | |
422 | return 0; | |
423 | } | |
424 | ||
425 | /* Macros for inflate(): */ | |
426 | ||
427 | /* check function to use adler32() for zlib or crc32() for gzip */ | |
428 | #ifdef GUNZIP | |
429 | # define UPDATE(check, buf, len) \ | |
430 | (state->flags ? crc32(check, buf, len) : adler32(check, buf, len)) | |
431 | #else | |
432 | # define UPDATE(check, buf, len) adler32(check, buf, len) | |
433 | #endif | |
434 | ||
435 | /* check macros for header crc */ | |
436 | #ifdef GUNZIP | |
437 | # define CRC2(check, word) \ | |
438 | do { \ | |
439 | hbuf[0] = (unsigned char)(word); \ | |
440 | hbuf[1] = (unsigned char)((word) >> 8); \ | |
441 | check = crc32(check, hbuf, 2); \ | |
442 | } while (0) | |
443 | ||
444 | # define CRC4(check, word) \ | |
445 | do { \ | |
446 | hbuf[0] = (unsigned char)(word); \ | |
447 | hbuf[1] = (unsigned char)((word) >> 8); \ | |
448 | hbuf[2] = (unsigned char)((word) >> 16); \ | |
449 | hbuf[3] = (unsigned char)((word) >> 24); \ | |
450 | check = crc32(check, hbuf, 4); \ | |
451 | } while (0) | |
452 | #endif | |
453 | ||
454 | /* Load registers with state in inflate() for speed */ | |
455 | #define LOAD() \ | |
456 | do { \ | |
457 | put = strm->next_out; \ | |
458 | left = strm->avail_out; \ | |
459 | next = strm->next_in; \ | |
460 | have = strm->avail_in; \ | |
461 | hold = state->hold; \ | |
462 | bits = state->bits; \ | |
463 | } while (0) | |
464 | ||
465 | /* Restore state from registers in inflate() */ | |
466 | #define RESTORE() \ | |
467 | do { \ | |
468 | strm->next_out = put; \ | |
469 | strm->avail_out = left; \ | |
470 | strm->next_in = next; \ | |
471 | strm->avail_in = have; \ | |
472 | state->hold = hold; \ | |
473 | state->bits = bits; \ | |
474 | } while (0) | |
475 | ||
476 | /* Clear the input bit accumulator */ | |
477 | #define INITBITS() \ | |
478 | do { \ | |
479 | hold = 0; \ | |
480 | bits = 0; \ | |
481 | } while (0) | |
482 | ||
483 | /* Get a byte of input into the bit accumulator, or return from inflate() | |
484 | if there is no input available. */ | |
485 | #define PULLBYTE() \ | |
486 | do { \ | |
487 | if (have == 0) goto inf_leave; \ | |
488 | have--; \ | |
489 | hold += (unsigned long)(*next++) << bits; \ | |
490 | bits += 8; \ | |
491 | } while (0) | |
492 | ||
493 | /* Assure that there are at least n bits in the bit accumulator. If there is | |
494 | not enough available input to do that, then return from inflate(). */ | |
495 | #define NEEDBITS(n) \ | |
496 | do { \ | |
497 | while (bits < (unsigned)(n)) \ | |
498 | PULLBYTE(); \ | |
499 | } while (0) | |
500 | ||
501 | /* Return the low n bits of the bit accumulator (n < 16) */ | |
502 | #define BITS(n) \ | |
503 | ((unsigned)hold & ((1U << (n)) - 1)) | |
504 | ||
505 | /* Remove n bits from the bit accumulator */ | |
506 | #define DROPBITS(n) \ | |
507 | do { \ | |
508 | hold >>= (n); \ | |
509 | bits -= (unsigned)(n); \ | |
510 | } while (0) | |
511 | ||
512 | /* Remove zero to seven bits as needed to go to a byte boundary */ | |
513 | #define BYTEBITS() \ | |
514 | do { \ | |
515 | hold >>= bits & 7; \ | |
516 | bits -= bits & 7; \ | |
517 | } while (0) | |
518 | ||
519 | /* | |
520 | inflate() uses a state machine to process as much input data and generate as | |
521 | much output data as possible before returning. The state machine is | |
522 | structured roughly as follows: | |
523 | ||
524 | for (;;) switch (state) { | |
525 | ... | |
526 | case STATEn: | |
527 | if (not enough input data or output space to make progress) | |
528 | return; | |
529 | ... make progress ... | |
530 | state = STATEm; | |
531 | break; | |
532 | ... | |
533 | } | |
534 | ||
535 | so when inflate() is called again, the same case is attempted again, and | |
536 | if the appropriate resources are provided, the machine proceeds to the | |
537 | next state. The NEEDBITS() macro is usually the way the state evaluates | |
538 | whether it can proceed or should return. NEEDBITS() does the return if | |
539 | the requested bits are not available. The typical use of the BITS macros | |
540 | is: | |
541 | ||
542 | NEEDBITS(n); | |
543 | ... do something with BITS(n) ... | |
544 | DROPBITS(n); | |
545 | ||
546 | where NEEDBITS(n) either returns from inflate() if there isn't enough | |
547 | input left to load n bits into the accumulator, or it continues. BITS(n) | |
548 | gives the low n bits in the accumulator. When done, DROPBITS(n) drops | |
549 | the low n bits off the accumulator. INITBITS() clears the accumulator | |
550 | and sets the number of available bits to zero. BYTEBITS() discards just | |
551 | enough bits to put the accumulator on a byte boundary. After BYTEBITS() | |
552 | and a NEEDBITS(8), then BITS(8) would return the next byte in the stream. | |
553 | ||
554 | NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return | |
555 | if there is no input available. The decoding of variable length codes uses | |
556 | PULLBYTE() directly in order to pull just enough bytes to decode the next | |
557 | code, and no more. | |
558 | ||
559 | Some states loop until they get enough input, making sure that enough | |
560 | state information is maintained to continue the loop where it left off | |
561 | if NEEDBITS() returns in the loop. For example, want, need, and keep | |
562 | would all have to actually be part of the saved state in case NEEDBITS() | |
563 | returns: | |
564 | ||
565 | case STATEw: | |
566 | while (want < need) { | |
567 | NEEDBITS(n); | |
568 | keep[want++] = BITS(n); | |
569 | DROPBITS(n); | |
570 | } | |
571 | state = STATEx; | |
572 | case STATEx: | |
573 | ||
574 | As shown above, if the next state is also the next case, then the break | |
575 | is omitted. | |
576 | ||
577 | A state may also return if there is not enough output space available to | |
578 | complete that state. Those states are copying stored data, writing a | |
579 | literal byte, and copying a matching string. | |
580 | ||
581 | When returning, a "goto inf_leave" is used to update the total counters, | |
582 | update the check value, and determine whether any progress has been made | |
583 | during that inflate() call in order to return the proper return code. | |
584 | Progress is defined as a change in either strm->avail_in or strm->avail_out. | |
585 | When there is a window, goto inf_leave will update the window with the last | |
586 | output written. If a goto inf_leave occurs in the middle of decompression | |
587 | and there is no window currently, goto inf_leave will create one and copy | |
588 | output to the window for the next call of inflate(). | |
589 | ||
590 | In this implementation, the flush parameter of inflate() only affects the | |
591 | return code (per zlib.h). inflate() always writes as much as possible to | |
592 | strm->next_out, given the space available and the provided input--the effect | |
593 | documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers | |
594 | the allocation of and copying into a sliding window until necessary, which | |
595 | provides the effect documented in zlib.h for Z_FINISH when the entire input | |
596 | stream available. So the only thing the flush parameter actually does is: | |
597 | when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it | |
598 | will return Z_BUF_ERROR if it has not reached the end of the stream. | |
599 | */ | |
600 | ||
601 | int ZEXPORT inflate(z_streamp strm, int flush) | |
602 | { | |
603 | struct inflate_state FAR *state; | |
604 | unsigned char FAR *next; /* next input */ | |
605 | unsigned char FAR *put; /* next output */ | |
606 | unsigned have, left; /* available input and output */ | |
607 | unsigned long hold; /* bit buffer */ | |
608 | unsigned bits; /* bits in bit buffer */ | |
609 | unsigned in, out; /* save starting available input and output */ | |
610 | unsigned copy; /* number of stored or match bytes to copy */ | |
611 | unsigned char FAR *from; /* where to copy match bytes from */ | |
612 | code here; /* current decoding table entry */ | |
613 | code last; /* parent table entry */ | |
614 | unsigned len; /* length to copy for repeats, bits to drop */ | |
615 | int ret; /* return code */ | |
616 | #ifdef GUNZIP | |
617 | unsigned char hbuf[4]; /* buffer for gzip header crc calculation */ | |
618 | #endif | |
619 | static const unsigned short order[19] = /* permutation of code lengths */ | |
620 | {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; | |
621 | ||
622 | if (strm == Z_NULL || strm->state == Z_NULL || strm->next_out == Z_NULL || | |
623 | (strm->next_in == Z_NULL && strm->avail_in != 0)) | |
624 | return Z_STREAM_ERROR; | |
625 | ||
626 | state = (struct inflate_state FAR *)strm->state; | |
627 | if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */ | |
628 | LOAD(); | |
629 | in = have; | |
630 | out = left; | |
631 | ret = Z_OK; | |
632 | for (;;) | |
633 | switch (state->mode) { | |
634 | case HEAD: | |
635 | if (state->wrap == 0) { | |
636 | state->mode = TYPEDO; | |
637 | break; | |
638 | } | |
639 | NEEDBITS(16); | |
640 | #ifdef GUNZIP | |
641 | if ((state->wrap & 2) && hold == 0x8b1f) { /* gzip header */ | |
642 | state->check = crc32(0L, Z_NULL, 0); | |
643 | CRC2(state->check, hold); | |
644 | INITBITS(); | |
645 | state->mode = FLAGS; | |
646 | break; | |
647 | } | |
648 | state->flags = 0; /* expect zlib header */ | |
649 | if (state->head != Z_NULL) | |
650 | state->head->done = -1; | |
651 | if (!(state->wrap & 1) || /* check if zlib header allowed */ | |
652 | #else | |
653 | if ( | |
654 | #endif | |
655 | ((BITS(8) << 8) + (hold >> 8)) % 31) { | |
656 | strm->msg = (char *)"incorrect header check"; | |
657 | state->mode = BAD; | |
658 | break; | |
659 | } | |
660 | if (BITS(4) != Z_DEFLATED) { | |
661 | strm->msg = (char *)"unknown compression method"; | |
662 | state->mode = BAD; | |
663 | break; | |
664 | } | |
665 | DROPBITS(4); | |
666 | len = BITS(4) + 8; | |
667 | if (state->wbits == 0) | |
668 | state->wbits = len; | |
669 | else if (len > state->wbits) { | |
670 | strm->msg = (char *)"invalid window size"; | |
671 | state->mode = BAD; | |
672 | break; | |
673 | } | |
674 | state->dmax = 1U << len; | |
675 | Tracev((stderr, "inflate: zlib header ok\n")); | |
676 | strm->adler = state->check = adler32(0L, Z_NULL, 0); | |
677 | state->mode = hold & 0x200 ? DICTID : TYPE; | |
678 | INITBITS(); | |
679 | break; | |
680 | #ifdef GUNZIP | |
681 | case FLAGS: | |
682 | NEEDBITS(16); | |
683 | state->flags = (int)(hold); | |
684 | if ((state->flags & 0xff) != Z_DEFLATED) { | |
685 | strm->msg = (char *)"unknown compression method"; | |
686 | state->mode = BAD; | |
687 | break; | |
688 | } | |
689 | if (state->flags & 0xe000) { | |
690 | strm->msg = (char *)"unknown header flags set"; | |
691 | state->mode = BAD; | |
692 | break; | |
693 | } | |
694 | if (state->head != Z_NULL) | |
695 | state->head->text = (int)((hold >> 8) & 1); | |
696 | if (state->flags & 0x0200) CRC2(state->check, hold); | |
697 | INITBITS(); | |
698 | state->mode = TIME; | |
699 | case TIME: | |
700 | NEEDBITS(32); | |
701 | if (state->head != Z_NULL) | |
702 | state->head->time = hold; | |
703 | if (state->flags & 0x0200) CRC4(state->check, hold); | |
704 | INITBITS(); | |
705 | state->mode = OS; | |
706 | case OS: | |
707 | NEEDBITS(16); | |
708 | if (state->head != Z_NULL) { | |
709 | state->head->xflags = (int)(hold & 0xff); | |
710 | state->head->os = (int)(hold >> 8); | |
711 | } | |
712 | if (state->flags & 0x0200) CRC2(state->check, hold); | |
713 | INITBITS(); | |
714 | state->mode = EXLEN; | |
715 | case EXLEN: | |
716 | if (state->flags & 0x0400) { | |
717 | NEEDBITS(16); | |
718 | state->length = (unsigned)(hold); | |
719 | if (state->head != Z_NULL) | |
720 | state->head->extra_len = (unsigned)hold; | |
721 | if (state->flags & 0x0200) CRC2(state->check, hold); | |
722 | INITBITS(); | |
723 | } | |
724 | else if (state->head != Z_NULL) | |
725 | state->head->extra = Z_NULL; | |
726 | state->mode = EXTRA; | |
727 | case EXTRA: | |
728 | if (state->flags & 0x0400) { | |
729 | copy = state->length; | |
730 | if (copy > have) copy = have; | |
731 | if (copy) { | |
732 | if (state->head != Z_NULL && | |
733 | state->head->extra != Z_NULL) { | |
734 | len = state->head->extra_len - state->length; | |
735 | zmemcpy(state->head->extra + len, next, | |
736 | len + copy > state->head->extra_max ? | |
737 | state->head->extra_max - len : copy); | |
738 | } | |
739 | if (state->flags & 0x0200) | |
740 | state->check = crc32(state->check, next, copy); | |
741 | have -= copy; | |
742 | next += copy; | |
743 | state->length -= copy; | |
744 | } | |
745 | if (state->length) goto inf_leave; | |
746 | } | |
747 | state->length = 0; | |
748 | state->mode = NAME; | |
749 | case NAME: | |
750 | if (state->flags & 0x0800) { | |
751 | if (have == 0) goto inf_leave; | |
752 | copy = 0; | |
753 | do { | |
754 | len = (unsigned)(next[copy++]); | |
755 | if (state->head != Z_NULL && | |
756 | state->head->name != Z_NULL && | |
757 | state->length < state->head->name_max) | |
758 | state->head->name[state->length++] = len; | |
759 | } while (len && copy < have); | |
760 | if (state->flags & 0x0200) | |
761 | state->check = crc32(state->check, next, copy); | |
762 | have -= copy; | |
763 | next += copy; | |
764 | if (len) goto inf_leave; | |
765 | } | |
766 | else if (state->head != Z_NULL) | |
767 | state->head->name = Z_NULL; | |
768 | state->length = 0; | |
769 | state->mode = COMMENT; | |
770 | case COMMENT: | |
771 | if (state->flags & 0x1000) { | |
772 | if (have == 0) goto inf_leave; | |
773 | copy = 0; | |
774 | do { | |
775 | len = (unsigned)(next[copy++]); | |
776 | if (state->head != Z_NULL && | |
777 | state->head->comment != Z_NULL && | |
778 | state->length < state->head->comm_max) | |
779 | state->head->comment[state->length++] = len; | |
780 | } while (len && copy < have); | |
781 | if (state->flags & 0x0200) | |
782 | state->check = crc32(state->check, next, copy); | |
783 | have -= copy; | |
784 | next += copy; | |
785 | if (len) goto inf_leave; | |
786 | } | |
787 | else if (state->head != Z_NULL) | |
788 | state->head->comment = Z_NULL; | |
789 | state->mode = HCRC; | |
790 | case HCRC: | |
791 | if (state->flags & 0x0200) { | |
792 | NEEDBITS(16); | |
793 | if (hold != (state->check & 0xffff)) { | |
794 | strm->msg = (char *)"header crc mismatch"; | |
795 | state->mode = BAD; | |
796 | break; | |
797 | } | |
798 | INITBITS(); | |
799 | } | |
800 | if (state->head != Z_NULL) { | |
801 | state->head->hcrc = (int)((state->flags >> 9) & 1); | |
802 | state->head->done = 1; | |
803 | } | |
804 | strm->adler = state->check = crc32(0L, Z_NULL, 0); | |
805 | state->mode = TYPE; | |
806 | break; | |
807 | #endif | |
808 | case DICTID: | |
809 | NEEDBITS(32); | |
810 | strm->adler = state->check = ZSWAP32(hold); | |
811 | INITBITS(); | |
812 | state->mode = DICT; | |
813 | case DICT: | |
814 | if (state->havedict == 0) { | |
815 | RESTORE(); | |
816 | return Z_NEED_DICT; | |
817 | } | |
818 | strm->adler = state->check = adler32(0L, Z_NULL, 0); | |
819 | state->mode = TYPE; | |
820 | case TYPE: | |
821 | if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave; | |
822 | case TYPEDO: | |
823 | if (state->last) { | |
824 | BYTEBITS(); | |
825 | state->mode = CHECK; | |
826 | break; | |
827 | } | |
828 | NEEDBITS(3); | |
829 | state->last = BITS(1); | |
830 | DROPBITS(1); | |
831 | switch (BITS(2)) { | |
832 | case 0: /* stored block */ | |
833 | Tracev((stderr, "inflate: stored block%s\n", | |
834 | state->last ? " (last)" : "")); | |
835 | state->mode = STORED; | |
836 | break; | |
837 | case 1: /* fixed block */ | |
838 | fixedtables(state); | |
839 | Tracev((stderr, "inflate: fixed codes block%s\n", | |
840 | state->last ? " (last)" : "")); | |
841 | state->mode = LEN_; /* decode codes */ | |
842 | if (flush == Z_TREES) { | |
843 | DROPBITS(2); | |
844 | goto inf_leave; | |
845 | } | |
846 | break; | |
847 | case 2: /* dynamic block */ | |
848 | Tracev((stderr, "inflate: dynamic codes block%s\n", | |
849 | state->last ? " (last)" : "")); | |
850 | state->mode = TABLE; | |
851 | break; | |
852 | case 3: | |
853 | strm->msg = (char *)"invalid block type"; | |
854 | state->mode = BAD; | |
855 | } | |
856 | DROPBITS(2); | |
857 | break; | |
858 | case STORED: | |
859 | BYTEBITS(); /* go to byte boundary */ | |
860 | NEEDBITS(32); | |
861 | if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) { | |
862 | strm->msg = (char *)"invalid stored block lengths"; | |
863 | state->mode = BAD; | |
864 | break; | |
865 | } | |
866 | state->length = (unsigned)hold & 0xffff; | |
867 | Tracev((stderr, "inflate: stored length %u\n", | |
868 | state->length)); | |
869 | INITBITS(); | |
870 | state->mode = COPY_; | |
871 | if (flush == Z_TREES) goto inf_leave; | |
872 | case COPY_: | |
873 | state->mode = COPY; | |
874 | case COPY: | |
875 | copy = state->length; | |
876 | if (copy) { | |
877 | if (copy > have) copy = have; | |
878 | if (copy > left) copy = left; | |
879 | if (copy == 0) goto inf_leave; | |
880 | zmemcpy(put, next, copy); | |
881 | have -= copy; | |
882 | next += copy; | |
883 | left -= copy; | |
884 | put += copy; | |
885 | state->length -= copy; | |
886 | break; | |
887 | } | |
888 | Tracev((stderr, "inflate: stored end\n")); | |
889 | state->mode = TYPE; | |
890 | break; | |
891 | case TABLE: | |
892 | NEEDBITS(14); | |
893 | state->nlen = BITS(5) + 257; | |
894 | DROPBITS(5); | |
895 | state->ndist = BITS(5) + 1; | |
896 | DROPBITS(5); | |
897 | state->ncode = BITS(4) + 4; | |
898 | DROPBITS(4); | |
899 | #ifndef PKZIP_BUG_WORKAROUND | |
900 | if (state->nlen > 286 || state->ndist > 30) { | |
901 | strm->msg = (char *)"too many length or distance symbols"; | |
902 | state->mode = BAD; | |
903 | break; | |
904 | } | |
905 | #endif | |
906 | Tracev((stderr, "inflate: table sizes ok\n")); | |
907 | state->have = 0; | |
908 | state->mode = LENLENS; | |
909 | case LENLENS: | |
910 | while (state->have < state->ncode) { | |
911 | NEEDBITS(3); | |
912 | state->lens[order[state->have++]] = (unsigned short)BITS(3); | |
913 | DROPBITS(3); | |
914 | } | |
915 | while (state->have < 19) | |
916 | state->lens[order[state->have++]] = 0; | |
917 | state->next = state->codes; | |
918 | state->lencode = (const code FAR *)(state->next); | |
919 | state->lenbits = 7; | |
920 | ret = inflate_table(CODES, state->lens, 19, &(state->next), | |
921 | &(state->lenbits), state->work); | |
922 | if (ret) { | |
923 | strm->msg = (char *)"invalid code lengths set"; | |
924 | state->mode = BAD; | |
925 | break; | |
926 | } | |
927 | Tracev((stderr, "inflate: code lengths ok\n")); | |
928 | state->have = 0; | |
929 | state->mode = CODELENS; | |
930 | case CODELENS: | |
931 | while (state->have < state->nlen + state->ndist) { | |
932 | for (;;) { | |
933 | here = state->lencode[BITS(state->lenbits)]; | |
934 | if ((unsigned)(here.bits) <= bits) break; | |
935 | PULLBYTE(); | |
936 | } | |
937 | if (here.val < 16) { | |
938 | DROPBITS(here.bits); | |
939 | state->lens[state->have++] = here.val; | |
940 | } | |
941 | else { | |
942 | if (here.val == 16) { | |
943 | NEEDBITS(here.bits + 2); | |
944 | DROPBITS(here.bits); | |
945 | if (state->have == 0) { | |
946 | strm->msg = (char *)"invalid bit length repeat"; | |
947 | state->mode = BAD; | |
948 | break; | |
949 | } | |
950 | len = state->lens[state->have - 1]; | |
951 | copy = 3 + BITS(2); | |
952 | DROPBITS(2); | |
953 | } | |
954 | else if (here.val == 17) { | |
955 | NEEDBITS(here.bits + 3); | |
956 | DROPBITS(here.bits); | |
957 | len = 0; | |
958 | copy = 3 + BITS(3); | |
959 | DROPBITS(3); | |
960 | } | |
961 | else { | |
962 | NEEDBITS(here.bits + 7); | |
963 | DROPBITS(here.bits); | |
964 | len = 0; | |
965 | copy = 11 + BITS(7); | |
966 | DROPBITS(7); | |
967 | } | |
968 | if (state->have + copy > state->nlen + state->ndist) { | |
969 | strm->msg = (char *)"invalid bit length repeat"; | |
970 | state->mode = BAD; | |
971 | break; | |
972 | } | |
973 | while (copy--) | |
974 | state->lens[state->have++] = (unsigned short)len; | |
975 | } | |
976 | } | |
977 | ||
978 | /* handle error breaks in while */ | |
979 | if (state->mode == BAD) break; | |
980 | ||
981 | /* check for end-of-block code (better have one) */ | |
982 | if (state->lens[256] == 0) { | |
983 | strm->msg = (char *)"invalid code -- missing end-of-block"; | |
984 | state->mode = BAD; | |
985 | break; | |
986 | } | |
987 | ||
988 | /* build code tables -- note: do not change the lenbits or distbits | |
989 | values here (9 and 6) without reading the comments in inftrees.h | |
990 | concerning the ENOUGH constants, which depend on those values */ | |
991 | state->next = state->codes; | |
992 | state->lencode = (const code FAR *)(state->next); | |
993 | state->lenbits = 9; | |
994 | ret = inflate_table(LENS, state->lens, state->nlen, &(state->next), | |
995 | &(state->lenbits), state->work); | |
996 | if (ret) { | |
997 | strm->msg = (char *)"invalid literal/lengths set"; | |
998 | state->mode = BAD; | |
999 | break; | |
1000 | } | |
1001 | state->distcode = (const code FAR *)(state->next); | |
1002 | state->distbits = 6; | |
1003 | ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist, | |
1004 | &(state->next), &(state->distbits), state->work); | |
1005 | if (ret) { | |
1006 | strm->msg = (char *)"invalid distances set"; | |
1007 | state->mode = BAD; | |
1008 | break; | |
1009 | } | |
1010 | Tracev((stderr, "inflate: codes ok\n")); | |
1011 | state->mode = LEN_; | |
1012 | if (flush == Z_TREES) goto inf_leave; | |
1013 | case LEN_: | |
1014 | state->mode = LEN; | |
1015 | case LEN: | |
1016 | if (have >= 6 && left >= 258) { | |
1017 | RESTORE(); | |
1018 | inflate_fast(strm, out); | |
1019 | LOAD(); | |
1020 | if (state->mode == TYPE) | |
1021 | state->back = -1; | |
1022 | break; | |
1023 | } | |
1024 | state->back = 0; | |
1025 | for (;;) { | |
1026 | here = state->lencode[BITS(state->lenbits)]; | |
1027 | if ((unsigned)(here.bits) <= bits) break; | |
1028 | PULLBYTE(); | |
1029 | } | |
1030 | if (here.op && (here.op & 0xf0) == 0) { | |
1031 | last = here; | |
1032 | for (;;) { | |
1033 | here = state->lencode[last.val + | |
1034 | (BITS(last.bits + last.op) >> last.bits)]; | |
1035 | if ((unsigned)(last.bits + here.bits) <= bits) break; | |
1036 | PULLBYTE(); | |
1037 | } | |
1038 | DROPBITS(last.bits); | |
1039 | state->back += last.bits; | |
1040 | } | |
1041 | DROPBITS(here.bits); | |
1042 | state->back += here.bits; | |
1043 | state->length = (unsigned)here.val; | |
1044 | if ((int)(here.op) == 0) { | |
1045 | Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ? | |
1046 | "inflate: literal '%c'\n" : | |
1047 | "inflate: literal 0x%02x\n", here.val)); | |
1048 | state->mode = LIT; | |
1049 | break; | |
1050 | } | |
1051 | if (here.op & 32) { | |
1052 | Tracevv((stderr, "inflate: end of block\n")); | |
1053 | state->back = -1; | |
1054 | state->mode = TYPE; | |
1055 | break; | |
1056 | } | |
1057 | if (here.op & 64) { | |
1058 | strm->msg = (char *)"invalid literal/length code"; | |
1059 | state->mode = BAD; | |
1060 | break; | |
1061 | } | |
1062 | state->extra = (unsigned)(here.op) & 15; | |
1063 | state->mode = LENEXT; | |
1064 | case LENEXT: | |
1065 | if (state->extra) { | |
1066 | NEEDBITS(state->extra); | |
1067 | state->length += BITS(state->extra); | |
1068 | DROPBITS(state->extra); | |
1069 | state->back += state->extra; | |
1070 | } | |
1071 | Tracevv((stderr, "inflate: length %u\n", state->length)); | |
1072 | state->was = state->length; | |
1073 | state->mode = DIST; | |
1074 | case DIST: | |
1075 | for (;;) { | |
1076 | here = state->distcode[BITS(state->distbits)]; | |
1077 | if ((unsigned)(here.bits) <= bits) break; | |
1078 | PULLBYTE(); | |
1079 | } | |
1080 | if ((here.op & 0xf0) == 0) { | |
1081 | last = here; | |
1082 | for (;;) { | |
1083 | here = state->distcode[last.val + | |
1084 | (BITS(last.bits + last.op) >> last.bits)]; | |
1085 | if ((unsigned)(last.bits + here.bits) <= bits) break; | |
1086 | PULLBYTE(); | |
1087 | } | |
1088 | DROPBITS(last.bits); | |
1089 | state->back += last.bits; | |
1090 | } | |
1091 | DROPBITS(here.bits); | |
1092 | state->back += here.bits; | |
1093 | if (here.op & 64) { | |
1094 | strm->msg = (char *)"invalid distance code"; | |
1095 | state->mode = BAD; | |
1096 | break; | |
1097 | } | |
1098 | state->offset = (unsigned)here.val; | |
1099 | state->extra = (unsigned)(here.op) & 15; | |
1100 | state->mode = DISTEXT; | |
1101 | case DISTEXT: | |
1102 | if (state->extra) { | |
1103 | NEEDBITS(state->extra); | |
1104 | state->offset += BITS(state->extra); | |
1105 | DROPBITS(state->extra); | |
1106 | state->back += state->extra; | |
1107 | } | |
1108 | #ifdef INFLATE_STRICT | |
1109 | if (state->offset > state->dmax) { | |
1110 | strm->msg = (char *)"invalid distance too far back"; | |
1111 | state->mode = BAD; | |
1112 | break; | |
1113 | } | |
1114 | #endif | |
1115 | Tracevv((stderr, "inflate: distance %u\n", state->offset)); | |
1116 | state->mode = MATCH; | |
1117 | case MATCH: | |
1118 | if (left == 0) goto inf_leave; | |
1119 | copy = out - left; | |
1120 | if (state->offset > copy) { /* copy from window */ | |
1121 | copy = state->offset - copy; | |
1122 | if (copy > state->whave) { | |
1123 | if (state->sane) { | |
1124 | strm->msg = (char *)"invalid distance too far back"; | |
1125 | state->mode = BAD; | |
1126 | break; | |
1127 | } | |
1128 | #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR | |
1129 | Trace((stderr, "inflate.c too far\n")); | |
1130 | copy -= state->whave; | |
1131 | if (copy > state->length) copy = state->length; | |
1132 | if (copy > left) copy = left; | |
1133 | left -= copy; | |
1134 | state->length -= copy; | |
1135 | do { | |
1136 | *put++ = 0; | |
1137 | } while (--copy); | |
1138 | if (state->length == 0) state->mode = LEN; | |
1139 | break; | |
1140 | #endif | |
1141 | } | |
1142 | if (copy > state->wnext) { | |
1143 | copy -= state->wnext; | |
1144 | from = state->window + (state->wsize - copy); | |
1145 | } | |
1146 | else | |
1147 | from = state->window + (state->wnext - copy); | |
1148 | if (copy > state->length) copy = state->length; | |
1149 | } | |
1150 | else { /* copy from output */ | |
1151 | from = put - state->offset; | |
1152 | copy = state->length; | |
1153 | } | |
1154 | if (copy > left) copy = left; | |
1155 | left -= copy; | |
1156 | state->length -= copy; | |
1157 | do { | |
1158 | *put++ = *from++; | |
1159 | } while (--copy); | |
1160 | if (state->length == 0) state->mode = LEN; | |
1161 | break; | |
1162 | case LIT: | |
1163 | if (left == 0) goto inf_leave; | |
1164 | *put++ = (unsigned char)(state->length); | |
1165 | left--; | |
1166 | state->mode = LEN; | |
1167 | break; | |
1168 | case CHECK: | |
1169 | if (state->wrap) { | |
1170 | NEEDBITS(32); | |
1171 | out -= left; | |
1172 | strm->total_out += out; | |
1173 | state->total += out; | |
1174 | if (out) | |
1175 | strm->adler = state->check = | |
1176 | UPDATE(state->check, put - out, out); | |
1177 | out = left; | |
1178 | if (( | |
1179 | #ifdef GUNZIP | |
1180 | state->flags ? hold : | |
1181 | #endif | |
1182 | ZSWAP32(hold)) != state->check) { | |
1183 | strm->msg = (char *)"incorrect data check"; | |
1184 | state->mode = BAD; | |
1185 | break; | |
1186 | } | |
1187 | INITBITS(); | |
1188 | Tracev((stderr, "inflate: check matches trailer\n")); | |
1189 | } | |
1190 | #ifdef GUNZIP | |
1191 | state->mode = LENGTH; | |
1192 | case LENGTH: | |
1193 | if (state->wrap && state->flags) { | |
1194 | NEEDBITS(32); | |
1195 | if (hold != (state->total & 0xffffffffUL)) { | |
1196 | strm->msg = (char *)"incorrect length check"; | |
1197 | state->mode = BAD; | |
1198 | break; | |
1199 | } | |
1200 | INITBITS(); | |
1201 | Tracev((stderr, "inflate: length matches trailer\n")); | |
1202 | } | |
1203 | #endif | |
1204 | state->mode = DONE; | |
1205 | case DONE: | |
1206 | ret = Z_STREAM_END; | |
1207 | goto inf_leave; | |
1208 | case BAD: | |
1209 | ret = Z_DATA_ERROR; | |
1210 | goto inf_leave; | |
1211 | case MEM: | |
1212 | return Z_MEM_ERROR; | |
1213 | case SYNC: | |
1214 | default: | |
1215 | return Z_STREAM_ERROR; | |
1216 | } | |
1217 | ||
1218 | /* | |
1219 | Return from inflate(), updating the total counts and the check value. | |
1220 | If there was no progress during the inflate() call, return a buffer | |
1221 | error. Call updatewindow() to create and/or update the window state. | |
1222 | Note: a memory error from inflate() is non-recoverable. | |
1223 | */ | |
1224 | inf_leave: | |
1225 | RESTORE(); | |
1226 | if (state->wsize || (out != strm->avail_out && state->mode < BAD && | |
1227 | (state->mode < CHECK || flush != Z_FINISH))) | |
1228 | if (updatewindow(strm, strm->next_out, out - strm->avail_out)) { | |
1229 | state->mode = MEM; | |
1230 | return Z_MEM_ERROR; | |
1231 | } | |
1232 | in -= strm->avail_in; | |
1233 | out -= strm->avail_out; | |
1234 | strm->total_in += in; | |
1235 | strm->total_out += out; | |
1236 | state->total += out; | |
1237 | if (state->wrap && out) | |
1238 | strm->adler = state->check = | |
1239 | UPDATE(state->check, strm->next_out - out, out); | |
1240 | strm->data_type = state->bits + (state->last ? 64 : 0) + | |
1241 | (state->mode == TYPE ? 128 : 0) + | |
1242 | (state->mode == LEN_ || state->mode == COPY_ ? 256 : 0); | |
1243 | if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK) | |
1244 | ret = Z_BUF_ERROR; | |
1245 | return ret; | |
1246 | } | |
1247 | ||
1248 | int ZEXPORT inflateEnd(z_streamp strm) | |
1249 | { | |
1250 | struct inflate_state FAR *state; | |
1251 | if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == Z_NULL) | |
1252 | return Z_STREAM_ERROR; | |
1253 | state = (struct inflate_state FAR *)strm->state; | |
1254 | if (state->window != Z_NULL) ZFREE(strm, state->window); | |
1255 | ZFREE(strm, strm->state); | |
1256 | strm->state = Z_NULL; | |
1257 | Tracev((stderr, "inflate: end\n")); | |
1258 | return Z_OK; | |
1259 | } | |
1260 | ||
1261 | int ZEXPORT inflateGetDictionary(z_streamp strm, Bytef *dictionary, uInt *dictLength) | |
1262 | { | |
1263 | struct inflate_state FAR *state; | |
1264 | ||
1265 | /* check state */ | |
1266 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
1267 | state = (struct inflate_state FAR *)strm->state; | |
1268 | ||
1269 | /* copy dictionary */ | |
1270 | if (state->whave && dictionary != Z_NULL) { | |
1271 | zmemcpy(dictionary, state->window + state->wnext, | |
1272 | state->whave - state->wnext); | |
1273 | zmemcpy(dictionary + state->whave - state->wnext, | |
1274 | state->window, state->wnext); | |
1275 | } | |
1276 | if (dictLength != Z_NULL) | |
1277 | *dictLength = state->whave; | |
1278 | return Z_OK; | |
1279 | } | |
1280 | ||
1281 | int ZEXPORT inflateSetDictionary(z_streamp strm, const Bytef *dictionary, uInt dictLength) | |
1282 | { | |
1283 | struct inflate_state FAR *state; | |
1284 | unsigned long dictid; | |
1285 | int ret; | |
1286 | ||
1287 | /* check state */ | |
1288 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
1289 | state = (struct inflate_state FAR *)strm->state; | |
1290 | if (state->wrap != 0 && state->mode != DICT) | |
1291 | return Z_STREAM_ERROR; | |
1292 | ||
1293 | /* check for correct dictionary identifier */ | |
1294 | if (state->mode == DICT) { | |
1295 | dictid = adler32(0L, Z_NULL, 0); | |
1296 | dictid = adler32(dictid, dictionary, dictLength); | |
1297 | if (dictid != state->check) | |
1298 | return Z_DATA_ERROR; | |
1299 | } | |
1300 | ||
1301 | /* copy dictionary to window using updatewindow(), which will amend the | |
1302 | existing dictionary if appropriate */ | |
1303 | ret = updatewindow(strm, dictionary + dictLength, dictLength); | |
1304 | if (ret) { | |
1305 | state->mode = MEM; | |
1306 | return Z_MEM_ERROR; | |
1307 | } | |
1308 | state->havedict = 1; | |
1309 | Tracev((stderr, "inflate: dictionary set\n")); | |
1310 | return Z_OK; | |
1311 | } | |
1312 | ||
1313 | int ZEXPORT inflateGetHeader(z_streamp strm, gz_headerp head) | |
1314 | { | |
1315 | struct inflate_state FAR *state; | |
1316 | ||
1317 | /* check state */ | |
1318 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
1319 | state = (struct inflate_state FAR *)strm->state; | |
1320 | if ((state->wrap & 2) == 0) return Z_STREAM_ERROR; | |
1321 | ||
1322 | /* save header structure */ | |
1323 | state->head = head; | |
1324 | head->done = 0; | |
1325 | return Z_OK; | |
1326 | } | |
1327 | ||
1328 | /* | |
1329 | Search buf[0..len-1] for the pattern: 0, 0, 0xff, 0xff. Return when found | |
1330 | or when out of input. When called, *have is the number of pattern bytes | |
1331 | found in order so far, in 0..3. On return *have is updated to the new | |
1332 | state. If on return *have equals four, then the pattern was found and the | |
1333 | return value is how many bytes were read including the last byte of the | |
1334 | pattern. If *have is less than four, then the pattern has not been found | |
1335 | yet and the return value is len. In the latter case, syncsearch() can be | |
1336 | called again with more data and the *have state. *have is initialized to | |
1337 | zero for the first call. | |
1338 | */ | |
1339 | local unsigned syncsearch(unsigned FAR *have, const unsigned char FAR *buf, unsigned len) | |
1340 | { | |
1341 | unsigned got; | |
1342 | unsigned next; | |
1343 | ||
1344 | got = *have; | |
1345 | next = 0; | |
1346 | while (next < len && got < 4) { | |
1347 | if ((int)(buf[next]) == (got < 2 ? 0 : 0xff)) | |
1348 | got++; | |
1349 | else if (buf[next]) | |
1350 | got = 0; | |
1351 | else | |
1352 | got = 4 - got; | |
1353 | next++; | |
1354 | } | |
1355 | *have = got; | |
1356 | return next; | |
1357 | } | |
1358 | ||
1359 | int ZEXPORT inflateSync(z_streamp strm) | |
1360 | { | |
1361 | unsigned len; /* number of bytes to look at or looked at */ | |
1362 | unsigned long in, out; /* temporary to save total_in and total_out */ | |
1363 | unsigned char buf[4]; /* to restore bit buffer to byte string */ | |
1364 | struct inflate_state FAR *state; | |
1365 | ||
1366 | /* check parameters */ | |
1367 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
1368 | state = (struct inflate_state FAR *)strm->state; | |
1369 | if (strm->avail_in == 0 && state->bits < 8) return Z_BUF_ERROR; | |
1370 | ||
1371 | /* if first time, start search in bit buffer */ | |
1372 | if (state->mode != SYNC) { | |
1373 | state->mode = SYNC; | |
1374 | state->hold <<= state->bits & 7; | |
1375 | state->bits -= state->bits & 7; | |
1376 | len = 0; | |
1377 | while (state->bits >= 8) { | |
1378 | buf[len++] = (unsigned char)(state->hold); | |
1379 | state->hold >>= 8; | |
1380 | state->bits -= 8; | |
1381 | } | |
1382 | state->have = 0; | |
1383 | syncsearch(&(state->have), buf, len); | |
1384 | } | |
1385 | ||
1386 | /* search available input */ | |
1387 | len = syncsearch(&(state->have), strm->next_in, strm->avail_in); | |
1388 | strm->avail_in -= len; | |
1389 | strm->next_in += len; | |
1390 | strm->total_in += len; | |
1391 | ||
1392 | /* return no joy or set up to restart inflate() on a new block */ | |
1393 | if (state->have != 4) return Z_DATA_ERROR; | |
1394 | in = strm->total_in; out = strm->total_out; | |
1395 | inflateReset(strm); | |
1396 | strm->total_in = in; strm->total_out = out; | |
1397 | state->mode = TYPE; | |
1398 | return Z_OK; | |
1399 | } | |
1400 | ||
1401 | /* | |
1402 | Returns true if inflate is currently at the end of a block generated by | |
1403 | Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP | |
1404 | implementation to provide an additional safety check. PPP uses | |
1405 | Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored | |
1406 | block. When decompressing, PPP checks that at the end of input packet, | |
1407 | inflate is waiting for these length bytes. | |
1408 | */ | |
1409 | int ZEXPORT inflateSyncPoint(z_streamp strm) | |
1410 | { | |
1411 | struct inflate_state FAR *state; | |
1412 | ||
1413 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; | |
1414 | state = (struct inflate_state FAR *)strm->state; | |
1415 | return state->mode == STORED && state->bits == 0; | |
1416 | } | |
1417 | ||
1418 | int ZEXPORT inflateCopy(z_streamp dest, z_streamp source) | |
1419 | { | |
1420 | struct inflate_state FAR *state; | |
1421 | struct inflate_state FAR *copy; | |
1422 | unsigned char FAR *window; | |
1423 | unsigned wsize; | |
1424 | ||
1425 | /* check input */ | |
1426 | if (dest == Z_NULL || source == Z_NULL || source->state == Z_NULL || | |
1427 | source->zalloc == Z_NULL || source->zfree == Z_NULL) | |
1428 | return Z_STREAM_ERROR; | |
1429 | state = (struct inflate_state FAR *)source->state; | |
1430 | ||
1431 | /* allocate space */ | |
1432 | copy = (struct inflate_state FAR *) | |
1433 | ZALLOC(source, 1, sizeof(struct inflate_state)); | |
1434 | if (copy == Z_NULL) return Z_MEM_ERROR; | |
1435 | window = Z_NULL; | |
1436 | if (state->window != Z_NULL) { | |
1437 | window = (unsigned char FAR *) | |
1438 | ZALLOC(source, 1U << state->wbits, sizeof(unsigned char)); | |
1439 | if (window == Z_NULL) { | |
1440 | ZFREE(source, copy); | |
1441 | return Z_MEM_ERROR; | |
1442 | } | |
1443 | } | |
1444 | ||
1445 | /* copy state */ | |
1446 | zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream)); | |
1447 | zmemcpy((voidpf)copy, (voidpf)state, sizeof(struct inflate_state)); | |
1448 | if (state->lencode >= state->codes && | |
1449 | state->lencode <= state->codes + ENOUGH - 1) { | |
1450 | copy->lencode = copy->codes + (state->lencode - state->codes); | |
1451 | copy->distcode = copy->codes + (state->distcode - state->codes); | |
1452 | } | |
1453 | copy->next = copy->codes + (state->next - state->codes); | |
1454 | if (window != Z_NULL) { | |
1455 | wsize = 1U << state->wbits; | |
1456 | zmemcpy(window, state->window, wsize); | |
1457 | } | |
1458 | copy->window = window; | |
1459 | dest->state = (struct internal_state FAR *)copy; | |
1460 | return Z_OK; | |
1461 | } | |
1462 | ||
1463 | int ZEXPORT inflateUndermine(z_streamp strm, int subvert) | |
1464 | { | |
1465 | struct inflate_state FAR *state = NULL; | |
1466 | ||
1467 | if (strm == Z_NULL || strm->state == Z_NULL) | |
1468 | return Z_STREAM_ERROR; | |
1469 | state = (struct inflate_state FAR *)strm->state; | |
1470 | state->sane = !subvert; | |
1471 | #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR | |
1472 | return Z_OK; | |
1473 | #else | |
1474 | state->sane = 1; | |
1475 | return Z_DATA_ERROR; | |
1476 | #endif | |
1477 | } | |
1478 | ||
1479 | long ZEXPORT inflateMark(z_streamp strm) | |
1480 | { | |
1481 | struct inflate_state FAR *state = NULL; | |
1482 | ||
1483 | if (strm == Z_NULL || strm->state == Z_NULL) | |
1484 | return -1L << 16; | |
1485 | state = (struct inflate_state FAR *)strm->state; | |
1486 | return ((long)(state->back) << 16) + | |
1487 | (state->mode == COPY ? state->length : | |
1488 | (state->mode == MATCH ? state->was - state->length : 0)); | |
1489 | } |