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5ca28f79 | 1 | /* inflate.c -- zlib decompression |
8e6b3536 | 2 | * Copyright (C) 1995-2022 Mark Adler |
5ca28f79 L |
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 */ | |
de1ab01e | 95 | local int inflateStateCheck OF((z_streamp strm)); |
5ca28f79 | 96 | local void fixedtables OF((struct inflate_state FAR *state)); |
da09a436 JB |
97 | local int updatewindow OF((z_streamp strm, const unsigned char FAR *end, |
98 | unsigned copy)); | |
5ca28f79 L |
99 | #ifdef BUILDFIXED |
100 | void makefixed OF((void)); | |
101 | #endif | |
da09a436 | 102 | local unsigned syncsearch OF((unsigned FAR *have, const unsigned char FAR *buf, |
5ca28f79 L |
103 | unsigned len)); |
104 | ||
de1ab01e NC |
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 | ||
5ca28f79 L |
119 | int ZEXPORT inflateResetKeep(strm) |
120 | z_streamp strm; | |
121 | { | |
122 | struct inflate_state FAR *state; | |
123 | ||
de1ab01e | 124 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
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; | |
8e6b3536 | 133 | state->flags = -1; |
5ca28f79 L |
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 | ||
de1ab01e | 150 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
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 */ | |
de1ab01e | 166 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
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 { | |
de1ab01e | 175 | wrap = (windowBits >> 4) + 5; |
5ca28f79 L |
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; | |
de1ab01e | 229 | state->strm = strm; |
5ca28f79 | 230 | state->window = Z_NULL; |
de1ab01e | 231 | state->mode = HEAD; /* to pass state test in inflateReset2() */ |
5ca28f79 L |
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 | ||
de1ab01e | 255 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
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 | } | |
de1ab01e | 262 | if (bits > 16 || state->bits + (uInt)bits > 32) return Z_STREAM_ERROR; |
5ca28f79 | 263 | value &= (1L << bits) - 1; |
de1ab01e NC |
264 | state->hold += (unsigned)value << state->bits; |
265 | state->bits += (uInt)bits; | |
5ca28f79 L |
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 | */ | |
da09a436 | 397 | local int updatewindow(strm, end, copy) |
5ca28f79 | 398 | z_streamp strm; |
da09a436 JB |
399 | const Bytef *end; |
400 | unsigned copy; | |
5ca28f79 L |
401 | { |
402 | struct inflate_state FAR *state; | |
da09a436 | 403 | unsigned dist; |
5ca28f79 L |
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 */ | |
5ca28f79 | 423 | if (copy >= state->wsize) { |
da09a436 | 424 | zmemcpy(state->window, end - state->wsize, state->wsize); |
5ca28f79 L |
425 | state->wnext = 0; |
426 | state->whave = state->wsize; | |
427 | } | |
428 | else { | |
429 | dist = state->wsize - state->wnext; | |
430 | if (dist > copy) dist = copy; | |
da09a436 | 431 | zmemcpy(state->window + state->wnext, end - copy, dist); |
5ca28f79 L |
432 | copy -= dist; |
433 | if (copy) { | |
da09a436 | 434 | zmemcpy(state->window, end - copy, copy); |
5ca28f79 L |
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 | |
8e6b3536 | 451 | # define UPDATE_CHECK(check, buf, len) \ |
5ca28f79 L |
452 | (state->flags ? crc32(check, buf, len) : adler32(check, buf, len)) |
453 | #else | |
8e6b3536 | 454 | # define UPDATE_CHECK(check, buf, len) adler32(check, buf, len) |
5ca28f79 L |
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; | |
da09a436 | 628 | z_const unsigned char FAR *next; /* next input */ |
5ca28f79 L |
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 | ||
de1ab01e | 646 | if (inflateStateCheck(strm) || strm->next_out == Z_NULL || |
5ca28f79 L |
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 */ | |
de1ab01e NC |
666 | if (state->wbits == 0) |
667 | state->wbits = 15; | |
5ca28f79 L |
668 | state->check = crc32(0L, Z_NULL, 0); |
669 | CRC2(state->check, hold); | |
670 | INITBITS(); | |
671 | state->mode = FLAGS; | |
672 | break; | |
673 | } | |
5ca28f79 L |
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; | |
de1ab01e | 694 | if (len > 15 || len > state->wbits) { |
5ca28f79 L |
695 | strm->msg = (char *)"invalid window size"; |
696 | state->mode = BAD; | |
697 | break; | |
698 | } | |
699 | state->dmax = 1U << len; | |
8e6b3536 | 700 | state->flags = 0; /* indicate zlib header */ |
5ca28f79 L |
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); | |
de1ab01e NC |
722 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
723 | CRC2(state->check, hold); | |
5ca28f79 L |
724 | INITBITS(); |
725 | state->mode = TIME; | |
8e6b3536 | 726 | /* fallthrough */ |
5ca28f79 L |
727 | case TIME: |
728 | NEEDBITS(32); | |
729 | if (state->head != Z_NULL) | |
730 | state->head->time = hold; | |
de1ab01e NC |
731 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
732 | CRC4(state->check, hold); | |
5ca28f79 L |
733 | INITBITS(); |
734 | state->mode = OS; | |
8e6b3536 | 735 | /* fallthrough */ |
5ca28f79 L |
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 | } | |
de1ab01e NC |
742 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
743 | CRC2(state->check, hold); | |
5ca28f79 L |
744 | INITBITS(); |
745 | state->mode = EXLEN; | |
8e6b3536 | 746 | /* fallthrough */ |
5ca28f79 L |
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; | |
de1ab01e NC |
753 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
754 | CRC2(state->check, hold); | |
5ca28f79 L |
755 | INITBITS(); |
756 | } | |
757 | else if (state->head != Z_NULL) | |
758 | state->head->extra = Z_NULL; | |
759 | state->mode = EXTRA; | |
8e6b3536 | 760 | /* fallthrough */ |
5ca28f79 L |
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 | } | |
de1ab01e | 773 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
5ca28f79 L |
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; | |
8e6b3536 | 783 | /* fallthrough */ |
5ca28f79 L |
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) | |
de1ab01e | 793 | state->head->name[state->length++] = (Bytef)len; |
5ca28f79 | 794 | } while (len && copy < have); |
de1ab01e | 795 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
5ca28f79 L |
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; | |
8e6b3536 | 805 | /* fallthrough */ |
5ca28f79 L |
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) | |
de1ab01e | 815 | state->head->comment[state->length++] = (Bytef)len; |
5ca28f79 | 816 | } while (len && copy < have); |
de1ab01e | 817 | if ((state->flags & 0x0200) && (state->wrap & 4)) |
5ca28f79 L |
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; | |
8e6b3536 | 826 | /* fallthrough */ |
5ca28f79 L |
827 | case HCRC: |
828 | if (state->flags & 0x0200) { | |
829 | NEEDBITS(16); | |
de1ab01e | 830 | if ((state->wrap & 4) && hold != (state->check & 0xffff)) { |
5ca28f79 L |
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; | |
8e6b3536 | 850 | /* fallthrough */ |
5ca28f79 L |
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; | |
8e6b3536 | 858 | /* fallthrough */ |
5ca28f79 L |
859 | case TYPE: |
860 | if (flush == Z_BLOCK || flush == Z_TREES) goto inf_leave; | |
8e6b3536 | 861 | /* fallthrough */ |
5ca28f79 L |
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; | |
8e6b3536 | 912 | /* fallthrough */ |
5ca28f79 L |
913 | case COPY_: |
914 | state->mode = COPY; | |
8e6b3536 | 915 | /* fallthrough */ |
5ca28f79 L |
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; | |
8e6b3536 | 951 | /* fallthrough */ |
5ca28f79 L |
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; | |
da09a436 | 961 | state->lencode = (const code FAR *)(state->next); |
5ca28f79 L |
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; | |
8e6b3536 | 973 | /* fallthrough */ |
5ca28f79 L |
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; | |
da09a436 | 1036 | state->lencode = (const code FAR *)(state->next); |
5ca28f79 L |
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 | } | |
da09a436 | 1045 | state->distcode = (const code FAR *)(state->next); |
5ca28f79 L |
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; | |
8e6b3536 | 1057 | /* fallthrough */ |
5ca28f79 L |
1058 | case LEN_: |
1059 | state->mode = LEN; | |
8e6b3536 | 1060 | /* fallthrough */ |
5ca28f79 L |
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; | |
8e6b3536 | 1110 | /* fallthrough */ |
5ca28f79 L |
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; | |
8e6b3536 | 1121 | /* fallthrough */ |
5ca28f79 L |
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; | |
8e6b3536 | 1149 | /* fallthrough */ |
5ca28f79 L |
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; | |
8e6b3536 | 1166 | /* fallthrough */ |
5ca28f79 L |
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; | |
de1ab01e | 1224 | if ((state->wrap & 4) && out) |
5ca28f79 | 1225 | strm->adler = state->check = |
8e6b3536 | 1226 | UPDATE_CHECK(state->check, put - out, out); |
5ca28f79 | 1227 | out = left; |
de1ab01e | 1228 | if ((state->wrap & 4) && ( |
5ca28f79 L |
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; | |
8e6b3536 | 1242 | /* fallthrough */ |
5ca28f79 L |
1243 | case LENGTH: |
1244 | if (state->wrap && state->flags) { | |
1245 | NEEDBITS(32); | |
8e6b3536 | 1246 | if ((state->wrap & 4) && hold != (state->total & 0xffffffff)) { |
5ca28f79 L |
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; | |
8e6b3536 | 1256 | /* fallthrough */ |
5ca28f79 L |
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: | |
8e6b3536 | 1266 | /* fallthrough */ |
5ca28f79 L |
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))) | |
da09a436 | 1281 | if (updatewindow(strm, strm->next_out, out - strm->avail_out)) { |
5ca28f79 L |
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; | |
de1ab01e | 1290 | if ((state->wrap & 4) && out) |
5ca28f79 | 1291 | strm->adler = state->check = |
8e6b3536 | 1292 | UPDATE_CHECK(state->check, strm->next_out - out, out); |
de1ab01e | 1293 | strm->data_type = (int)state->bits + (state->last ? 64 : 0) + |
5ca28f79 L |
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; | |
de1ab01e | 1305 | if (inflateStateCheck(strm)) |
5ca28f79 L |
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 | ||
da09a436 JB |
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 */ | |
de1ab01e | 1323 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
da09a436 JB |
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 | ||
5ca28f79 L |
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; | |
5ca28f79 L |
1345 | int ret; |
1346 | ||
1347 | /* check state */ | |
de1ab01e | 1348 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
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 */ | |
da09a436 | 1363 | ret = updatewindow(strm, dictionary + dictLength, dictLength); |
5ca28f79 L |
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 inflateGetHeader(strm, head) | |
1374 | z_streamp strm; | |
1375 | gz_headerp head; | |
1376 | { | |
1377 | struct inflate_state FAR *state; | |
1378 | ||
1379 | /* check state */ | |
de1ab01e | 1380 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
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; | |
da09a436 | 1403 | const unsigned char FAR *buf; |
5ca28f79 L |
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 */ | |
8e6b3536 | 1428 | int flags; /* temporary to save header status */ |
5ca28f79 L |
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 */ | |
de1ab01e | 1434 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
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; | |
8e6b3536 NC |
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; | |
5ca28f79 L |
1466 | in = strm->total_in; out = strm->total_out; |
1467 | inflateReset(strm); | |
1468 | strm->total_in = in; strm->total_out = out; | |
8e6b3536 | 1469 | state->flags = flags; |
5ca28f79 L |
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 | ||
de1ab01e | 1487 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 L |
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 */ | |
de1ab01e | 1502 | if (inflateStateCheck(source) || dest == Z_NULL) |
5ca28f79 L |
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)); | |
de1ab01e | 1523 | copy->strm = dest; |
5ca28f79 L |
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 | ||
de1ab01e | 1545 | if (inflateStateCheck(strm)) return Z_STREAM_ERROR; |
5ca28f79 | 1546 | state = (struct inflate_state FAR *)strm->state; |
5ca28f79 | 1547 | #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR |
de1ab01e | 1548 | state->sane = !subvert; |
5ca28f79 L |
1549 | return Z_OK; |
1550 | #else | |
de1ab01e | 1551 | (void)subvert; |
5ca28f79 L |
1552 | state->sane = 1; |
1553 | return Z_DATA_ERROR; | |
1554 | #endif | |
1555 | } | |
1556 | ||
de1ab01e NC |
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; | |
8e6b3536 | 1565 | if (check && state->wrap) |
de1ab01e NC |
1566 | state->wrap |= 4; |
1567 | else | |
1568 | state->wrap &= ~4; | |
1569 | return Z_OK; | |
1570 | } | |
1571 | ||
5ca28f79 L |
1572 | long ZEXPORT inflateMark(strm) |
1573 | z_streamp strm; | |
1574 | { | |
1575 | struct inflate_state FAR *state; | |
1576 | ||
de1ab01e NC |
1577 | if (inflateStateCheck(strm)) |
1578 | return -(1L << 16); | |
5ca28f79 | 1579 | state = (struct inflate_state FAR *)strm->state; |
de1ab01e | 1580 | return (long)(((unsigned long)((long)state->back)) << 16) + |
5ca28f79 L |
1581 | (state->mode == COPY ? state->length : |
1582 | (state->mode == MATCH ? state->was - state->length : 0)); | |
1583 | } | |
de1ab01e NC |
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 | } |