1 | /* inflate.c -- zlib decompression |
2 | * Copyright (C) 1995-2005 Mark Adler |
3 | * For conditions of distribution and use, see copyright notice in zlib.h |
4 | * |
5 | * Based on zlib 1.2.3 but modified for the Linux Kernel by |
6 | * Richard Purdie <richard@openedhand.com> |
7 | * |
8 | * Changes mainly for static instead of dynamic memory allocation |
9 | * |
10 | */ |
11 | |
12 | #include <linux/zutil.h> |
13 | #include "inftrees.h" |
14 | #include "inflate.h" |
15 | #include "inffast.h" |
16 | #include "infutil.h" |
17 | |
18 | /* architecture-specific bits */ |
19 | #ifdef CONFIG_ZLIB_DFLTCC |
20 | # include "../zlib_dfltcc/dfltcc_inflate.h" |
21 | #else |
22 | #define INFLATE_RESET_HOOK(strm) do {} while (0) |
23 | #define INFLATE_TYPEDO_HOOK(strm, flush) do {} while (0) |
24 | #define INFLATE_NEED_UPDATEWINDOW(strm) 1 |
25 | #define INFLATE_NEED_CHECKSUM(strm) 1 |
26 | #endif |
27 | |
28 | int zlib_inflate_workspacesize(void) |
29 | { |
30 | return sizeof(struct inflate_workspace); |
31 | } |
32 | |
33 | int zlib_inflateReset(z_streamp strm) |
34 | { |
35 | struct inflate_state *state; |
36 | |
37 | if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR; |
38 | state = (struct inflate_state *)strm->state; |
39 | strm->total_in = strm->total_out = state->total = 0; |
40 | strm->msg = NULL; |
41 | strm->adler = 1; /* to support ill-conceived Java test suite */ |
42 | state->mode = HEAD; |
43 | state->last = 0; |
44 | state->havedict = 0; |
45 | state->dmax = 32768U; |
46 | state->hold = 0; |
47 | state->bits = 0; |
48 | state->lencode = state->distcode = state->next = state->codes; |
49 | |
50 | /* Initialise Window */ |
51 | state->wsize = 1U << state->wbits; |
52 | state->write = 0; |
53 | state->whave = 0; |
54 | |
55 | INFLATE_RESET_HOOK(strm); |
56 | return Z_OK; |
57 | } |
58 | |
59 | int zlib_inflateInit2(z_streamp strm, int windowBits) |
60 | { |
61 | struct inflate_state *state; |
62 | |
63 | if (strm == NULL) return Z_STREAM_ERROR; |
64 | strm->msg = NULL; /* in case we return an error */ |
65 | |
66 | state = &WS(strm)->inflate_state; |
67 | strm->state = (struct internal_state *)state; |
68 | |
69 | if (windowBits < 0) { |
70 | state->wrap = 0; |
71 | windowBits = -windowBits; |
72 | } |
73 | else { |
74 | state->wrap = (windowBits >> 4) + 1; |
75 | } |
76 | if (windowBits < 8 || windowBits > 15) { |
77 | return Z_STREAM_ERROR; |
78 | } |
79 | state->wbits = (unsigned)windowBits; |
80 | #ifdef CONFIG_ZLIB_DFLTCC |
81 | /* |
82 | * DFLTCC requires the window to be page aligned. |
83 | * Thus, we overallocate and take the aligned portion of the buffer. |
84 | */ |
85 | state->window = PTR_ALIGN(&WS(strm)->working_window[0], PAGE_SIZE); |
86 | #else |
87 | state->window = &WS(strm)->working_window[0]; |
88 | #endif |
89 | |
90 | return zlib_inflateReset(strm); |
91 | } |
92 | |
93 | /* |
94 | Return state with length and distance decoding tables and index sizes set to |
95 | fixed code decoding. This returns fixed tables from inffixed.h. |
96 | */ |
97 | static void zlib_fixedtables(struct inflate_state *state) |
98 | { |
99 | # include "inffixed.h" |
100 | state->lencode = lenfix; |
101 | state->lenbits = 9; |
102 | state->distcode = distfix; |
103 | state->distbits = 5; |
104 | } |
105 | |
106 | |
107 | /* |
108 | Update the window with the last wsize (normally 32K) bytes written before |
109 | returning. This is only called when a window is already in use, or when |
110 | output has been written during this inflate call, but the end of the deflate |
111 | stream has not been reached yet. It is also called to window dictionary data |
112 | when a dictionary is loaded. |
113 | |
114 | Providing output buffers larger than 32K to inflate() should provide a speed |
115 | advantage, since only the last 32K of output is copied to the sliding window |
116 | upon return from inflate(), and since all distances after the first 32K of |
117 | output will fall in the output data, making match copies simpler and faster. |
118 | The advantage may be dependent on the size of the processor's data caches. |
119 | */ |
120 | static void zlib_updatewindow(z_streamp strm, unsigned out) |
121 | { |
122 | struct inflate_state *state; |
123 | unsigned copy, dist; |
124 | |
125 | state = (struct inflate_state *)strm->state; |
126 | |
127 | /* copy state->wsize or less output bytes into the circular window */ |
128 | copy = out - strm->avail_out; |
129 | if (copy >= state->wsize) { |
130 | memcpy(to: state->window, from: strm->next_out - state->wsize, len: state->wsize); |
131 | state->write = 0; |
132 | state->whave = state->wsize; |
133 | } |
134 | else { |
135 | dist = state->wsize - state->write; |
136 | if (dist > copy) dist = copy; |
137 | memcpy(to: state->window + state->write, from: strm->next_out - copy, len: dist); |
138 | copy -= dist; |
139 | if (copy) { |
140 | memcpy(to: state->window, from: strm->next_out - copy, len: copy); |
141 | state->write = copy; |
142 | state->whave = state->wsize; |
143 | } |
144 | else { |
145 | state->write += dist; |
146 | if (state->write == state->wsize) state->write = 0; |
147 | if (state->whave < state->wsize) state->whave += dist; |
148 | } |
149 | } |
150 | } |
151 | |
152 | |
153 | /* |
154 | * At the end of a Deflate-compressed PPP packet, we expect to have seen |
155 | * a `stored' block type value but not the (zero) length bytes. |
156 | */ |
157 | /* |
158 | Returns true if inflate is currently at the end of a block generated by |
159 | Z_SYNC_FLUSH or Z_FULL_FLUSH. This function is used by one PPP |
160 | implementation to provide an additional safety check. PPP uses |
161 | Z_SYNC_FLUSH but removes the length bytes of the resulting empty stored |
162 | block. When decompressing, PPP checks that at the end of input packet, |
163 | inflate is waiting for these length bytes. |
164 | */ |
165 | static int zlib_inflateSyncPacket(z_streamp strm) |
166 | { |
167 | struct inflate_state *state; |
168 | |
169 | if (strm == NULL || strm->state == NULL) return Z_STREAM_ERROR; |
170 | state = (struct inflate_state *)strm->state; |
171 | |
172 | if (state->mode == STORED && state->bits == 0) { |
173 | state->mode = TYPE; |
174 | return Z_OK; |
175 | } |
176 | return Z_DATA_ERROR; |
177 | } |
178 | |
179 | /* Macros for inflate(): */ |
180 | |
181 | /* check function to use adler32() for zlib or crc32() for gzip */ |
182 | #define UPDATE(check, buf, len) zlib_adler32(check, buf, len) |
183 | |
184 | /* Load registers with state in inflate() for speed */ |
185 | #define LOAD() \ |
186 | do { \ |
187 | put = strm->next_out; \ |
188 | left = strm->avail_out; \ |
189 | next = strm->next_in; \ |
190 | have = strm->avail_in; \ |
191 | hold = state->hold; \ |
192 | bits = state->bits; \ |
193 | } while (0) |
194 | |
195 | /* Restore state from registers in inflate() */ |
196 | #define RESTORE() \ |
197 | do { \ |
198 | strm->next_out = put; \ |
199 | strm->avail_out = left; \ |
200 | strm->next_in = next; \ |
201 | strm->avail_in = have; \ |
202 | state->hold = hold; \ |
203 | state->bits = bits; \ |
204 | } while (0) |
205 | |
206 | /* Clear the input bit accumulator */ |
207 | #define INITBITS() \ |
208 | do { \ |
209 | hold = 0; \ |
210 | bits = 0; \ |
211 | } while (0) |
212 | |
213 | /* Get a byte of input into the bit accumulator, or return from inflate() |
214 | if there is no input available. */ |
215 | #define PULLBYTE() \ |
216 | do { \ |
217 | if (have == 0) goto inf_leave; \ |
218 | have--; \ |
219 | hold += (unsigned long)(*next++) << bits; \ |
220 | bits += 8; \ |
221 | } while (0) |
222 | |
223 | /* Assure that there are at least n bits in the bit accumulator. If there is |
224 | not enough available input to do that, then return from inflate(). */ |
225 | #define NEEDBITS(n) \ |
226 | do { \ |
227 | while (bits < (unsigned)(n)) \ |
228 | PULLBYTE(); \ |
229 | } while (0) |
230 | |
231 | /* Return the low n bits of the bit accumulator (n < 16) */ |
232 | #define BITS(n) \ |
233 | ((unsigned)hold & ((1U << (n)) - 1)) |
234 | |
235 | /* Remove n bits from the bit accumulator */ |
236 | #define DROPBITS(n) \ |
237 | do { \ |
238 | hold >>= (n); \ |
239 | bits -= (unsigned)(n); \ |
240 | } while (0) |
241 | |
242 | /* Remove zero to seven bits as needed to go to a byte boundary */ |
243 | #define BYTEBITS() \ |
244 | do { \ |
245 | hold >>= bits & 7; \ |
246 | bits -= bits & 7; \ |
247 | } while (0) |
248 | |
249 | /* |
250 | inflate() uses a state machine to process as much input data and generate as |
251 | much output data as possible before returning. The state machine is |
252 | structured roughly as follows: |
253 | |
254 | for (;;) switch (state) { |
255 | ... |
256 | case STATEn: |
257 | if (not enough input data or output space to make progress) |
258 | return; |
259 | ... make progress ... |
260 | state = STATEm; |
261 | break; |
262 | ... |
263 | } |
264 | |
265 | so when inflate() is called again, the same case is attempted again, and |
266 | if the appropriate resources are provided, the machine proceeds to the |
267 | next state. The NEEDBITS() macro is usually the way the state evaluates |
268 | whether it can proceed or should return. NEEDBITS() does the return if |
269 | the requested bits are not available. The typical use of the BITS macros |
270 | is: |
271 | |
272 | NEEDBITS(n); |
273 | ... do something with BITS(n) ... |
274 | DROPBITS(n); |
275 | |
276 | where NEEDBITS(n) either returns from inflate() if there isn't enough |
277 | input left to load n bits into the accumulator, or it continues. BITS(n) |
278 | gives the low n bits in the accumulator. When done, DROPBITS(n) drops |
279 | the low n bits off the accumulator. INITBITS() clears the accumulator |
280 | and sets the number of available bits to zero. BYTEBITS() discards just |
281 | enough bits to put the accumulator on a byte boundary. After BYTEBITS() |
282 | and a NEEDBITS(8), then BITS(8) would return the next byte in the stream. |
283 | |
284 | NEEDBITS(n) uses PULLBYTE() to get an available byte of input, or to return |
285 | if there is no input available. The decoding of variable length codes uses |
286 | PULLBYTE() directly in order to pull just enough bytes to decode the next |
287 | code, and no more. |
288 | |
289 | Some states loop until they get enough input, making sure that enough |
290 | state information is maintained to continue the loop where it left off |
291 | if NEEDBITS() returns in the loop. For example, want, need, and keep |
292 | would all have to actually be part of the saved state in case NEEDBITS() |
293 | returns: |
294 | |
295 | case STATEw: |
296 | while (want < need) { |
297 | NEEDBITS(n); |
298 | keep[want++] = BITS(n); |
299 | DROPBITS(n); |
300 | } |
301 | state = STATEx; |
302 | case STATEx: |
303 | |
304 | As shown above, if the next state is also the next case, then the break |
305 | is omitted. |
306 | |
307 | A state may also return if there is not enough output space available to |
308 | complete that state. Those states are copying stored data, writing a |
309 | literal byte, and copying a matching string. |
310 | |
311 | When returning, a "goto inf_leave" is used to update the total counters, |
312 | update the check value, and determine whether any progress has been made |
313 | during that inflate() call in order to return the proper return code. |
314 | Progress is defined as a change in either strm->avail_in or strm->avail_out. |
315 | When there is a window, goto inf_leave will update the window with the last |
316 | output written. If a goto inf_leave occurs in the middle of decompression |
317 | and there is no window currently, goto inf_leave will create one and copy |
318 | output to the window for the next call of inflate(). |
319 | |
320 | In this implementation, the flush parameter of inflate() only affects the |
321 | return code (per zlib.h). inflate() always writes as much as possible to |
322 | strm->next_out, given the space available and the provided input--the effect |
323 | documented in zlib.h of Z_SYNC_FLUSH. Furthermore, inflate() always defers |
324 | the allocation of and copying into a sliding window until necessary, which |
325 | provides the effect documented in zlib.h for Z_FINISH when the entire input |
326 | stream available. So the only thing the flush parameter actually does is: |
327 | when flush is set to Z_FINISH, inflate() cannot return Z_OK. Instead it |
328 | will return Z_BUF_ERROR if it has not reached the end of the stream. |
329 | */ |
330 | |
331 | int zlib_inflate(z_streamp strm, int flush) |
332 | { |
333 | struct inflate_state *state; |
334 | const unsigned char *next; /* next input */ |
335 | unsigned char *put; /* next output */ |
336 | unsigned have, left; /* available input and output */ |
337 | unsigned long hold; /* bit buffer */ |
338 | unsigned bits; /* bits in bit buffer */ |
339 | unsigned in, out; /* save starting available input and output */ |
340 | unsigned copy; /* number of stored or match bytes to copy */ |
341 | unsigned char *from; /* where to copy match bytes from */ |
342 | code this; /* current decoding table entry */ |
343 | code last; /* parent table entry */ |
344 | unsigned len; /* length to copy for repeats, bits to drop */ |
345 | int ret; /* return code */ |
346 | static const unsigned short order[19] = /* permutation of code lengths */ |
347 | {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; |
348 | |
349 | /* Do not check for strm->next_out == NULL here as ppc zImage |
350 | inflates to strm->next_out = 0 */ |
351 | |
352 | if (strm == NULL || strm->state == NULL || |
353 | (strm->next_in == NULL && strm->avail_in != 0)) |
354 | return Z_STREAM_ERROR; |
355 | |
356 | state = (struct inflate_state *)strm->state; |
357 | |
358 | if (state->mode == TYPE) state->mode = TYPEDO; /* skip check */ |
359 | LOAD(); |
360 | in = have; |
361 | out = left; |
362 | ret = Z_OK; |
363 | for (;;) |
364 | switch (state->mode) { |
365 | case HEAD: |
366 | if (state->wrap == 0) { |
367 | state->mode = TYPEDO; |
368 | break; |
369 | } |
370 | NEEDBITS(16); |
371 | if ( |
372 | ((BITS(8) << 8) + (hold >> 8)) % 31) { |
373 | strm->msg = (char *)"incorrect header check" ; |
374 | state->mode = BAD; |
375 | break; |
376 | } |
377 | if (BITS(4) != Z_DEFLATED) { |
378 | strm->msg = (char *)"unknown compression method" ; |
379 | state->mode = BAD; |
380 | break; |
381 | } |
382 | DROPBITS(4); |
383 | len = BITS(4) + 8; |
384 | if (len > state->wbits) { |
385 | strm->msg = (char *)"invalid window size" ; |
386 | state->mode = BAD; |
387 | break; |
388 | } |
389 | state->dmax = 1U << len; |
390 | strm->adler = state->check = zlib_adler32(adler: 0L, NULL, len: 0); |
391 | state->mode = hold & 0x200 ? DICTID : TYPE; |
392 | INITBITS(); |
393 | break; |
394 | case DICTID: |
395 | NEEDBITS(32); |
396 | strm->adler = state->check = REVERSE(hold); |
397 | INITBITS(); |
398 | state->mode = DICT; |
399 | fallthrough; |
400 | case DICT: |
401 | if (state->havedict == 0) { |
402 | RESTORE(); |
403 | return Z_NEED_DICT; |
404 | } |
405 | strm->adler = state->check = zlib_adler32(adler: 0L, NULL, len: 0); |
406 | state->mode = TYPE; |
407 | fallthrough; |
408 | case TYPE: |
409 | if (flush == Z_BLOCK) goto inf_leave; |
410 | fallthrough; |
411 | case TYPEDO: |
412 | INFLATE_TYPEDO_HOOK(strm, flush); |
413 | if (state->last) { |
414 | BYTEBITS(); |
415 | state->mode = CHECK; |
416 | break; |
417 | } |
418 | NEEDBITS(3); |
419 | state->last = BITS(1); |
420 | DROPBITS(1); |
421 | switch (BITS(2)) { |
422 | case 0: /* stored block */ |
423 | state->mode = STORED; |
424 | break; |
425 | case 1: /* fixed block */ |
426 | zlib_fixedtables(state); |
427 | state->mode = LEN; /* decode codes */ |
428 | break; |
429 | case 2: /* dynamic block */ |
430 | state->mode = TABLE; |
431 | break; |
432 | case 3: |
433 | strm->msg = (char *)"invalid block type" ; |
434 | state->mode = BAD; |
435 | } |
436 | DROPBITS(2); |
437 | break; |
438 | case STORED: |
439 | BYTEBITS(); /* go to byte boundary */ |
440 | NEEDBITS(32); |
441 | if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) { |
442 | strm->msg = (char *)"invalid stored block lengths" ; |
443 | state->mode = BAD; |
444 | break; |
445 | } |
446 | state->length = (unsigned)hold & 0xffff; |
447 | INITBITS(); |
448 | state->mode = COPY; |
449 | fallthrough; |
450 | case COPY: |
451 | copy = state->length; |
452 | if (copy) { |
453 | if (copy > have) copy = have; |
454 | if (copy > left) copy = left; |
455 | if (copy == 0) goto inf_leave; |
456 | memcpy(to: put, from: next, len: copy); |
457 | have -= copy; |
458 | next += copy; |
459 | left -= copy; |
460 | put += copy; |
461 | state->length -= copy; |
462 | break; |
463 | } |
464 | state->mode = TYPE; |
465 | break; |
466 | case TABLE: |
467 | NEEDBITS(14); |
468 | state->nlen = BITS(5) + 257; |
469 | DROPBITS(5); |
470 | state->ndist = BITS(5) + 1; |
471 | DROPBITS(5); |
472 | state->ncode = BITS(4) + 4; |
473 | DROPBITS(4); |
474 | #ifndef PKZIP_BUG_WORKAROUND |
475 | if (state->nlen > 286 || state->ndist > 30) { |
476 | strm->msg = (char *)"too many length or distance symbols" ; |
477 | state->mode = BAD; |
478 | break; |
479 | } |
480 | #endif |
481 | state->have = 0; |
482 | state->mode = LENLENS; |
483 | fallthrough; |
484 | case LENLENS: |
485 | while (state->have < state->ncode) { |
486 | NEEDBITS(3); |
487 | state->lens[order[state->have++]] = (unsigned short)BITS(3); |
488 | DROPBITS(3); |
489 | } |
490 | while (state->have < 19) |
491 | state->lens[order[state->have++]] = 0; |
492 | state->next = state->codes; |
493 | state->lencode = (code const *)(state->next); |
494 | state->lenbits = 7; |
495 | ret = zlib_inflate_table(type: CODES, lens: state->lens, codes: 19, table: &(state->next), |
496 | bits: &(state->lenbits), work: state->work); |
497 | if (ret) { |
498 | strm->msg = (char *)"invalid code lengths set" ; |
499 | state->mode = BAD; |
500 | break; |
501 | } |
502 | state->have = 0; |
503 | state->mode = CODELENS; |
504 | fallthrough; |
505 | case CODELENS: |
506 | while (state->have < state->nlen + state->ndist) { |
507 | for (;;) { |
508 | this = state->lencode[BITS(state->lenbits)]; |
509 | if ((unsigned)(this.bits) <= bits) break; |
510 | PULLBYTE(); |
511 | } |
512 | if (this.val < 16) { |
513 | NEEDBITS(this.bits); |
514 | DROPBITS(this.bits); |
515 | state->lens[state->have++] = this.val; |
516 | } |
517 | else { |
518 | if (this.val == 16) { |
519 | NEEDBITS(this.bits + 2); |
520 | DROPBITS(this.bits); |
521 | if (state->have == 0) { |
522 | strm->msg = (char *)"invalid bit length repeat" ; |
523 | state->mode = BAD; |
524 | break; |
525 | } |
526 | len = state->lens[state->have - 1]; |
527 | copy = 3 + BITS(2); |
528 | DROPBITS(2); |
529 | } |
530 | else if (this.val == 17) { |
531 | NEEDBITS(this.bits + 3); |
532 | DROPBITS(this.bits); |
533 | len = 0; |
534 | copy = 3 + BITS(3); |
535 | DROPBITS(3); |
536 | } |
537 | else { |
538 | NEEDBITS(this.bits + 7); |
539 | DROPBITS(this.bits); |
540 | len = 0; |
541 | copy = 11 + BITS(7); |
542 | DROPBITS(7); |
543 | } |
544 | if (state->have + copy > state->nlen + state->ndist) { |
545 | strm->msg = (char *)"invalid bit length repeat" ; |
546 | state->mode = BAD; |
547 | break; |
548 | } |
549 | while (copy--) |
550 | state->lens[state->have++] = (unsigned short)len; |
551 | } |
552 | } |
553 | |
554 | /* handle error breaks in while */ |
555 | if (state->mode == BAD) break; |
556 | |
557 | /* build code tables */ |
558 | state->next = state->codes; |
559 | state->lencode = (code const *)(state->next); |
560 | state->lenbits = 9; |
561 | ret = zlib_inflate_table(type: LENS, lens: state->lens, codes: state->nlen, table: &(state->next), |
562 | bits: &(state->lenbits), work: state->work); |
563 | if (ret) { |
564 | strm->msg = (char *)"invalid literal/lengths set" ; |
565 | state->mode = BAD; |
566 | break; |
567 | } |
568 | state->distcode = (code const *)(state->next); |
569 | state->distbits = 6; |
570 | ret = zlib_inflate_table(type: DISTS, lens: state->lens + state->nlen, codes: state->ndist, |
571 | table: &(state->next), bits: &(state->distbits), work: state->work); |
572 | if (ret) { |
573 | strm->msg = (char *)"invalid distances set" ; |
574 | state->mode = BAD; |
575 | break; |
576 | } |
577 | state->mode = LEN; |
578 | fallthrough; |
579 | case LEN: |
580 | if (have >= 6 && left >= 258) { |
581 | RESTORE(); |
582 | inflate_fast(strm, start: out); |
583 | LOAD(); |
584 | break; |
585 | } |
586 | for (;;) { |
587 | this = state->lencode[BITS(state->lenbits)]; |
588 | if ((unsigned)(this.bits) <= bits) break; |
589 | PULLBYTE(); |
590 | } |
591 | if (this.op && (this.op & 0xf0) == 0) { |
592 | last = this; |
593 | for (;;) { |
594 | this = state->lencode[last.val + |
595 | (BITS(last.bits + last.op) >> last.bits)]; |
596 | if ((unsigned)(last.bits + this.bits) <= bits) break; |
597 | PULLBYTE(); |
598 | } |
599 | DROPBITS(last.bits); |
600 | } |
601 | DROPBITS(this.bits); |
602 | state->length = (unsigned)this.val; |
603 | if ((int)(this.op) == 0) { |
604 | state->mode = LIT; |
605 | break; |
606 | } |
607 | if (this.op & 32) { |
608 | state->mode = TYPE; |
609 | break; |
610 | } |
611 | if (this.op & 64) { |
612 | strm->msg = (char *)"invalid literal/length code" ; |
613 | state->mode = BAD; |
614 | break; |
615 | } |
616 | state->extra = (unsigned)(this.op) & 15; |
617 | state->mode = LENEXT; |
618 | fallthrough; |
619 | case LENEXT: |
620 | if (state->extra) { |
621 | NEEDBITS(state->extra); |
622 | state->length += BITS(state->extra); |
623 | DROPBITS(state->extra); |
624 | } |
625 | state->mode = DIST; |
626 | fallthrough; |
627 | case DIST: |
628 | for (;;) { |
629 | this = state->distcode[BITS(state->distbits)]; |
630 | if ((unsigned)(this.bits) <= bits) break; |
631 | PULLBYTE(); |
632 | } |
633 | if ((this.op & 0xf0) == 0) { |
634 | last = this; |
635 | for (;;) { |
636 | this = state->distcode[last.val + |
637 | (BITS(last.bits + last.op) >> last.bits)]; |
638 | if ((unsigned)(last.bits + this.bits) <= bits) break; |
639 | PULLBYTE(); |
640 | } |
641 | DROPBITS(last.bits); |
642 | } |
643 | DROPBITS(this.bits); |
644 | if (this.op & 64) { |
645 | strm->msg = (char *)"invalid distance code" ; |
646 | state->mode = BAD; |
647 | break; |
648 | } |
649 | state->offset = (unsigned)this.val; |
650 | state->extra = (unsigned)(this.op) & 15; |
651 | state->mode = DISTEXT; |
652 | fallthrough; |
653 | case DISTEXT: |
654 | if (state->extra) { |
655 | NEEDBITS(state->extra); |
656 | state->offset += BITS(state->extra); |
657 | DROPBITS(state->extra); |
658 | } |
659 | #ifdef INFLATE_STRICT |
660 | if (state->offset > state->dmax) { |
661 | strm->msg = (char *)"invalid distance too far back" ; |
662 | state->mode = BAD; |
663 | break; |
664 | } |
665 | #endif |
666 | if (state->offset > state->whave + out - left) { |
667 | strm->msg = (char *)"invalid distance too far back" ; |
668 | state->mode = BAD; |
669 | break; |
670 | } |
671 | state->mode = MATCH; |
672 | fallthrough; |
673 | case MATCH: |
674 | if (left == 0) goto inf_leave; |
675 | copy = out - left; |
676 | if (state->offset > copy) { /* copy from window */ |
677 | copy = state->offset - copy; |
678 | if (copy > state->write) { |
679 | copy -= state->write; |
680 | from = state->window + (state->wsize - copy); |
681 | } |
682 | else |
683 | from = state->window + (state->write - copy); |
684 | if (copy > state->length) copy = state->length; |
685 | } |
686 | else { /* copy from output */ |
687 | from = put - state->offset; |
688 | copy = state->length; |
689 | } |
690 | if (copy > left) copy = left; |
691 | left -= copy; |
692 | state->length -= copy; |
693 | do { |
694 | *put++ = *from++; |
695 | } while (--copy); |
696 | if (state->length == 0) state->mode = LEN; |
697 | break; |
698 | case LIT: |
699 | if (left == 0) goto inf_leave; |
700 | *put++ = (unsigned char)(state->length); |
701 | left--; |
702 | state->mode = LEN; |
703 | break; |
704 | case CHECK: |
705 | if (state->wrap) { |
706 | NEEDBITS(32); |
707 | out -= left; |
708 | strm->total_out += out; |
709 | state->total += out; |
710 | if (INFLATE_NEED_CHECKSUM(strm) && out) |
711 | strm->adler = state->check = |
712 | UPDATE(state->check, put - out, out); |
713 | out = left; |
714 | if (( |
715 | REVERSE(hold)) != state->check) { |
716 | strm->msg = (char *)"incorrect data check" ; |
717 | state->mode = BAD; |
718 | break; |
719 | } |
720 | INITBITS(); |
721 | } |
722 | state->mode = DONE; |
723 | fallthrough; |
724 | case DONE: |
725 | ret = Z_STREAM_END; |
726 | goto inf_leave; |
727 | case BAD: |
728 | ret = Z_DATA_ERROR; |
729 | goto inf_leave; |
730 | case MEM: |
731 | return Z_MEM_ERROR; |
732 | case SYNC: |
733 | default: |
734 | return Z_STREAM_ERROR; |
735 | } |
736 | |
737 | /* |
738 | Return from inflate(), updating the total counts and the check value. |
739 | If there was no progress during the inflate() call, return a buffer |
740 | error. Call zlib_updatewindow() to create and/or update the window state. |
741 | */ |
742 | inf_leave: |
743 | RESTORE(); |
744 | if (INFLATE_NEED_UPDATEWINDOW(strm) && |
745 | (state->wsize || (state->mode < CHECK && out != strm->avail_out))) |
746 | zlib_updatewindow(strm, out); |
747 | |
748 | in -= strm->avail_in; |
749 | out -= strm->avail_out; |
750 | strm->total_in += in; |
751 | strm->total_out += out; |
752 | state->total += out; |
753 | if (INFLATE_NEED_CHECKSUM(strm) && state->wrap && out) |
754 | strm->adler = state->check = |
755 | UPDATE(state->check, strm->next_out - out, out); |
756 | |
757 | strm->data_type = state->bits + (state->last ? 64 : 0) + |
758 | (state->mode == TYPE ? 128 : 0); |
759 | |
760 | if (flush == Z_PACKET_FLUSH && ret == Z_OK && |
761 | strm->avail_out != 0 && strm->avail_in == 0) |
762 | return zlib_inflateSyncPacket(strm); |
763 | |
764 | if (((in == 0 && out == 0) || flush == Z_FINISH) && ret == Z_OK) |
765 | ret = Z_BUF_ERROR; |
766 | |
767 | return ret; |
768 | } |
769 | |
770 | int zlib_inflateEnd(z_streamp strm) |
771 | { |
772 | if (strm == NULL || strm->state == NULL) |
773 | return Z_STREAM_ERROR; |
774 | return Z_OK; |
775 | } |
776 | |
777 | /* |
778 | * This subroutine adds the data at next_in/avail_in to the output history |
779 | * without performing any output. The output buffer must be "caught up"; |
780 | * i.e. no pending output but this should always be the case. The state must |
781 | * be waiting on the start of a block (i.e. mode == TYPE or HEAD). On exit, |
782 | * the output will also be caught up, and the checksum will have been updated |
783 | * if need be. |
784 | */ |
785 | int zlib_inflateIncomp(z_stream *z) |
786 | { |
787 | struct inflate_state *state = (struct inflate_state *)z->state; |
788 | Byte *saved_no = z->next_out; |
789 | uInt saved_ao = z->avail_out; |
790 | |
791 | if (state->mode != TYPE && state->mode != HEAD) |
792 | return Z_DATA_ERROR; |
793 | |
794 | /* Setup some variables to allow misuse of updateWindow */ |
795 | z->avail_out = 0; |
796 | z->next_out = (unsigned char*)z->next_in + z->avail_in; |
797 | |
798 | zlib_updatewindow(strm: z, out: z->avail_in); |
799 | |
800 | /* Restore saved variables */ |
801 | z->avail_out = saved_ao; |
802 | z->next_out = saved_no; |
803 | |
804 | z->adler = state->check = |
805 | UPDATE(state->check, z->next_in, z->avail_in); |
806 | |
807 | z->total_out += z->avail_in; |
808 | z->total_in += z->avail_in; |
809 | z->next_in += z->avail_in; |
810 | state->total += z->avail_in; |
811 | z->avail_in = 0; |
812 | |
813 | return Z_OK; |
814 | } |
815 | |