| Geant4 Cross Reference |
1 /* infback.c -- inflate using a call-back interface
2 * Copyright (C) 1995-2022 Mark Adler
3 * For conditions of distribution and use, see copyright notice in zlib.h
4 */
5
6 /*
7 This code is largely copied from inflate.c. Normally either infback.o or
8 inflate.o would be linked into an application--not both. The interface
9 with inffast.c is retained so that optimized assembler-coded versions of
10 inflate_fast() can be used with either inflate.c or infback.c.
11 */
12
13 #include "zutil.h"
14 #include "inftrees.h"
15 #include "inflate.h"
16 #include "inffast.h"
17
18 /* function prototypes */
19 local void fixedtables OF((struct inflate_state FAR *state));
20
21 /*
22 strm provides memory allocation functions in zalloc and zfree, or
23 Z_NULL to use the library memory allocation functions.
24
25 windowBits is in the range 8..15, and window is a user-supplied
26 window and output buffer that is 2**windowBits bytes.
27 */
28 int ZEXPORT inflateBackInit_(strm, windowBits, window, version, stream_size)
29 z_streamp strm;
30 int windowBits;
31 unsigned char FAR *window;
32 const char *version;
33 int stream_size;
34 {
35 struct inflate_state FAR *state;
36
37 if (version == Z_NULL || version[0] != ZLIB_VERSION[0] ||
38 stream_size != (int)(sizeof(z_stream)))
39 return Z_VERSION_ERROR;
40 if (strm == Z_NULL || window == Z_NULL ||
41 windowBits < 8 || windowBits > 15)
42 return Z_STREAM_ERROR;
43 strm->msg = Z_NULL; /* in case we return an error */
44 if (strm->zalloc == (alloc_func)0) {
45 #ifdef Z_SOLO
46 return Z_STREAM_ERROR;
47 #else
48 strm->zalloc = zcalloc;
49 strm->opaque = (voidpf)0;
50 #endif
51 }
52 if (strm->zfree == (free_func)0)
53 #ifdef Z_SOLO
54 return Z_STREAM_ERROR;
55 #else
56 strm->zfree = zcfree;
57 #endif
58 state = (struct inflate_state FAR *)ZALLOC(strm, 1,
59 sizeof(struct inflate_state));
60 if (state == Z_NULL) return Z_MEM_ERROR;
61 Tracev((stderr, "inflate: allocated\n"));
62 strm->state = (struct internal_state FAR *)state;
63 state->dmax = 32768U;
64 state->wbits = (uInt)windowBits;
65 state->wsize = 1U << windowBits;
66 state->window = window;
67 state->wnext = 0;
68 state->whave = 0;
69 state->sane = 1;
70 return Z_OK;
71 }
72
73 /*
74 Return state with length and distance decoding tables and index sizes set to
75 fixed code decoding. Normally this returns fixed tables from inffixed.h.
76 If BUILDFIXED is defined, then instead this routine builds the tables the
77 first time it's called, and returns those tables the first time and
78 thereafter. This reduces the size of the code by about 2K bytes, in
79 exchange for a little execution time. However, BUILDFIXED should not be
80 used for threaded applications, since the rewriting of the tables and virgin
81 may not be thread-safe.
82 */
83 local void fixedtables(state)
84 struct inflate_state FAR *state;
85 {
86 #ifdef BUILDFIXED
87 static int virgin = 1;
88 static code *lenfix, *distfix;
89 static code fixed[544];
90
91 /* build fixed huffman tables if first call (may not be thread safe) */
92 if (virgin) {
93 unsigned sym, bits;
94 static code *next;
95
96 /* literal/length table */
97 sym = 0;
98 while (sym < 144) state->lens[sym++] = 8;
99 while (sym < 256) state->lens[sym++] = 9;
100 while (sym < 280) state->lens[sym++] = 7;
101 while (sym < 288) state->lens[sym++] = 8;
102 next = fixed;
103 lenfix = next;
104 bits = 9;
105 inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
106
107 /* distance table */
108 sym = 0;
109 while (sym < 32) state->lens[sym++] = 5;
110 distfix = next;
111 bits = 5;
112 inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
113
114 /* do this just once */
115 virgin = 0;
116 }
117 #else /* !BUILDFIXED */
118 # include "inffixed.h"
119 #endif /* BUILDFIXED */
120 state->lencode = lenfix;
121 state->lenbits = 9;
122 state->distcode = distfix;
123 state->distbits = 5;
124 }
125
126 /* Macros for inflateBack(): */
127
128 /* Load returned state from inflate_fast() */
129 #define LOAD() \
130 do { \
131 put = strm->next_out; \
132 left = strm->avail_out; \
133 next = strm->next_in; \
134 have = strm->avail_in; \
135 hold = state->hold; \
136 bits = state->bits; \
137 } while (0)
138
139 /* Set state from registers for inflate_fast() */
140 #define RESTORE() \
141 do { \
142 strm->next_out = put; \
143 strm->avail_out = left; \
144 strm->next_in = next; \
145 strm->avail_in = have; \
146 state->hold = hold; \
147 state->bits = bits; \
148 } while (0)
149
150 /* Clear the input bit accumulator */
151 #define INITBITS() \
152 do { \
153 hold = 0; \
154 bits = 0; \
155 } while (0)
156
157 /* Assure that some input is available. If input is requested, but denied,
158 then return a Z_BUF_ERROR from inflateBack(). */
159 #define PULL() \
160 do { \
161 if (have == 0) { \
162 have = in(in_desc, &next); \
163 if (have == 0) { \
164 next = Z_NULL; \
165 ret = Z_BUF_ERROR; \
166 goto inf_leave; \
167 } \
168 } \
169 } while (0)
170
171 /* Get a byte of input into the bit accumulator, or return from inflateBack()
172 with an error if there is no input available. */
173 #define PULLBYTE() \
174 do { \
175 PULL(); \
176 have--; \
177 hold += (unsigned long)(*next++) << bits; \
178 bits += 8; \
179 } while (0)
180
181 /* Assure that there are at least n bits in the bit accumulator. If there is
182 not enough available input to do that, then return from inflateBack() with
183 an error. */
184 #define NEEDBITS(n) \
185 do { \
186 while (bits < (unsigned)(n)) \
187 PULLBYTE(); \
188 } while (0)
189
190 /* Return the low n bits of the bit accumulator (n < 16) */
191 #define BITS(n) \
192 ((unsigned)hold & ((1U << (n)) - 1))
193
194 /* Remove n bits from the bit accumulator */
195 #define DROPBITS(n) \
196 do { \
197 hold >>= (n); \
198 bits -= (unsigned)(n); \
199 } while (0)
200
201 /* Remove zero to seven bits as needed to go to a byte boundary */
202 #define BYTEBITS() \
203 do { \
204 hold >>= bits & 7; \
205 bits -= bits & 7; \
206 } while (0)
207
208 /* Assure that some output space is available, by writing out the window
209 if it's full. If the write fails, return from inflateBack() with a
210 Z_BUF_ERROR. */
211 #define ROOM() \
212 do { \
213 if (left == 0) { \
214 put = state->window; \
215 left = state->wsize; \
216 state->whave = left; \
217 if (out(out_desc, put, left)) { \
218 ret = Z_BUF_ERROR; \
219 goto inf_leave; \
220 } \
221 } \
222 } while (0)
223
224 /*
225 strm provides the memory allocation functions and window buffer on input,
226 and provides information on the unused input on return. For Z_DATA_ERROR
227 returns, strm will also provide an error message.
228
229 in() and out() are the call-back input and output functions. When
230 inflateBack() needs more input, it calls in(). When inflateBack() has
231 filled the window with output, or when it completes with data in the
232 window, it calls out() to write out the data. The application must not
233 change the provided input until in() is called again or inflateBack()
234 returns. The application must not change the window/output buffer until
235 inflateBack() returns.
236
237 in() and out() are called with a descriptor parameter provided in the
238 inflateBack() call. This parameter can be a structure that provides the
239 information required to do the read or write, as well as accumulated
240 information on the input and output such as totals and check values.
241
242 in() should return zero on failure. out() should return non-zero on
243 failure. If either in() or out() fails, than inflateBack() returns a
244 Z_BUF_ERROR. strm->next_in can be checked for Z_NULL to see whether it
245 was in() or out() that caused in the error. Otherwise, inflateBack()
246 returns Z_STREAM_END on success, Z_DATA_ERROR for an deflate format
247 error, or Z_MEM_ERROR if it could not allocate memory for the state.
248 inflateBack() can also return Z_STREAM_ERROR if the input parameters
249 are not correct, i.e. strm is Z_NULL or the state was not initialized.
250 */
251 int ZEXPORT inflateBack(strm, in, in_desc, out, out_desc)
252 z_streamp strm;
253 in_func in;
254 void FAR *in_desc;
255 out_func out;
256 void FAR *out_desc;
257 {
258 struct inflate_state FAR *state;
259 z_const unsigned char FAR *next; /* next input */
260 unsigned char FAR *put; /* next output */
261 unsigned have, left; /* available input and output */
262 unsigned long hold; /* bit buffer */
263 unsigned bits; /* bits in bit buffer */
264 unsigned copy; /* number of stored or match bytes to copy */
265 unsigned char FAR *from; /* where to copy match bytes from */
266 code here; /* current decoding table entry */
267 code last; /* parent table entry */
268 unsigned len; /* length to copy for repeats, bits to drop */
269 int ret; /* return code */
270 static const unsigned short order[19] = /* permutation of code lengths */
271 {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
272
273 /* Check that the strm exists and that the state was initialized */
274 if (strm == Z_NULL || strm->state == Z_NULL)
275 return Z_STREAM_ERROR;
276 state = (struct inflate_state FAR *)strm->state;
277
278 /* Reset the state */
279 strm->msg = Z_NULL;
280 state->mode = TYPE;
281 state->last = 0;
282 state->whave = 0;
283 next = strm->next_in;
284 have = next != Z_NULL ? strm->avail_in : 0;
285 hold = 0;
286 bits = 0;
287 put = state->window;
288 left = state->wsize;
289
290 /* Inflate until end of block marked as last */
291 for (;;)
292 switch (state->mode) {
293 case TYPE:
294 /* determine and dispatch block type */
295 if (state->last) {
296 BYTEBITS();
297 state->mode = DONE;
298 break;
299 }
300 NEEDBITS(3);
301 state->last = BITS(1);
302 DROPBITS(1);
303 switch (BITS(2)) {
304 case 0: /* stored block */
305 Tracev((stderr, "inflate: stored block%s\n",
306 state->last ? " (last)" : ""));
307 state->mode = STORED;
308 break;
309 case 1: /* fixed block */
310 fixedtables(state);
311 Tracev((stderr, "inflate: fixed codes block%s\n",
312 state->last ? " (last)" : ""));
313 state->mode = LEN; /* decode codes */
314 break;
315 case 2: /* dynamic block */
316 Tracev((stderr, "inflate: dynamic codes block%s\n",
317 state->last ? " (last)" : ""));
318 state->mode = TABLE;
319 break;
320 case 3:
321 strm->msg = (char *)"invalid block type";
322 state->mode = BAD;
323 }
324 DROPBITS(2);
325 break;
326
327 case STORED:
328 /* get and verify stored block length */
329 BYTEBITS(); /* go to byte boundary */
330 NEEDBITS(32);
331 if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
332 strm->msg = (char *)"invalid stored block lengths";
333 state->mode = BAD;
334 break;
335 }
336 state->length = (unsigned)hold & 0xffff;
337 Tracev((stderr, "inflate: stored length %u\n",
338 state->length));
339 INITBITS();
340
341 /* copy stored block from input to output */
342 while (state->length != 0) {
343 copy = state->length;
344 PULL();
345 ROOM();
346 if (copy > have) copy = have;
347 if (copy > left) copy = left;
348 zmemcpy(put, next, copy);
349 have -= copy;
350 next += copy;
351 left -= copy;
352 put += copy;
353 state->length -= copy;
354 }
355 Tracev((stderr, "inflate: stored end\n"));
356 state->mode = TYPE;
357 break;
358
359 case TABLE:
360 /* get dynamic table entries descriptor */
361 NEEDBITS(14);
362 state->nlen = BITS(5) + 257;
363 DROPBITS(5);
364 state->ndist = BITS(5) + 1;
365 DROPBITS(5);
366 state->ncode = BITS(4) + 4;
367 DROPBITS(4);
368 #ifndef PKZIP_BUG_WORKAROUND
369 if (state->nlen > 286 || state->ndist > 30) {
370 strm->msg = (char *)"too many length or distance symbols";
371 state->mode = BAD;
372 break;
373 }
374 #endif
375 Tracev((stderr, "inflate: table sizes ok\n"));
376
377 /* get code length code lengths (not a typo) */
378 state->have = 0;
379 while (state->have < state->ncode) {
380 NEEDBITS(3);
381 state->lens[order[state->have++]] = (unsigned short)BITS(3);
382 DROPBITS(3);
383 }
384 while (state->have < 19)
385 state->lens[order[state->have++]] = 0;
386 state->next = state->codes;
387 state->lencode = (code const FAR *)(state->next);
388 state->lenbits = 7;
389 ret = inflate_table(CODES, state->lens, 19, &(state->next),
390 &(state->lenbits), state->work);
391 if (ret) {
392 strm->msg = (char *)"invalid code lengths set";
393 state->mode = BAD;
394 break;
395 }
396 Tracev((stderr, "inflate: code lengths ok\n"));
397
398 /* get length and distance code code lengths */
399 state->have = 0;
400 while (state->have < state->nlen + state->ndist) {
401 for (;;) {
402 here = state->lencode[BITS(state->lenbits)];
403 if ((unsigned)(here.bits) <= bits) break;
404 PULLBYTE();
405 }
406 if (here.val < 16) {
407 DROPBITS(here.bits);
408 state->lens[state->have++] = here.val;
409 }
410 else {
411 if (here.val == 16) {
412 NEEDBITS(here.bits + 2);
413 DROPBITS(here.bits);
414 if (state->have == 0) {
415 strm->msg = (char *)"invalid bit length repeat";
416 state->mode = BAD;
417 break;
418 }
419 len = (unsigned)(state->lens[state->have - 1]);
420 copy = 3 + BITS(2);
421 DROPBITS(2);
422 }
423 else if (here.val == 17) {
424 NEEDBITS(here.bits + 3);
425 DROPBITS(here.bits);
426 len = 0;
427 copy = 3 + BITS(3);
428 DROPBITS(3);
429 }
430 else {
431 NEEDBITS(here.bits + 7);
432 DROPBITS(here.bits);
433 len = 0;
434 copy = 11 + BITS(7);
435 DROPBITS(7);
436 }
437 if (state->have + copy > state->nlen + state->ndist) {
438 strm->msg = (char *)"invalid bit length repeat";
439 state->mode = BAD;
440 break;
441 }
442 while (copy--)
443 state->lens[state->have++] = (unsigned short)len;
444 }
445 }
446
447 /* handle error breaks in while */
448 if (state->mode == BAD) break;
449
450 /* check for end-of-block code (better have one) */
451 if (state->lens[256] == 0) {
452 strm->msg = (char *)"invalid code -- missing end-of-block";
453 state->mode = BAD;
454 break;
455 }
456
457 /* build code tables -- note: do not change the lenbits or distbits
458 values here (9 and 6) without reading the comments in inftrees.h
459 concerning the ENOUGH constants, which depend on those values */
460 state->next = state->codes;
461 state->lencode = (code const FAR *)(state->next);
462 state->lenbits = 9;
463 ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
464 &(state->lenbits), state->work);
465 if (ret) {
466 strm->msg = (char *)"invalid literal/lengths set";
467 state->mode = BAD;
468 break;
469 }
470 state->distcode = (code const FAR *)(state->next);
471 state->distbits = 6;
472 ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
473 &(state->next), &(state->distbits), state->work);
474 if (ret) {
475 strm->msg = (char *)"invalid distances set";
476 state->mode = BAD;
477 break;
478 }
479 Tracev((stderr, "inflate: codes ok\n"));
480 state->mode = LEN;
481 /* fallthrough */
482
483 case LEN:
484 /* use inflate_fast() if we have enough input and output */
485 if (have >= 6 && left >= 258) {
486 RESTORE();
487 if (state->whave < state->wsize)
488 state->whave = state->wsize - left;
489 inflate_fast(strm, state->wsize);
490 LOAD();
491 break;
492 }
493
494 /* get a literal, length, or end-of-block code */
495 for (;;) {
496 here = state->lencode[BITS(state->lenbits)];
497 if ((unsigned)(here.bits) <= bits) break;
498 PULLBYTE();
499 }
500 if (here.op && (here.op & 0xf0) == 0) {
501 last = here;
502 for (;;) {
503 here = state->lencode[last.val +
504 (BITS(last.bits + last.op) >> last.bits)];
505 if ((unsigned)(last.bits + here.bits) <= bits) break;
506 PULLBYTE();
507 }
508 DROPBITS(last.bits);
509 }
510 DROPBITS(here.bits);
511 state->length = (unsigned)here.val;
512
513 /* process literal */
514 if (here.op == 0) {
515 Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
516 "inflate: literal '%c'\n" :
517 "inflate: literal 0x%02x\n", here.val));
518 ROOM();
519 *put++ = (unsigned char)(state->length);
520 left--;
521 state->mode = LEN;
522 break;
523 }
524
525 /* process end of block */
526 if (here.op & 32) {
527 Tracevv((stderr, "inflate: end of block\n"));
528 state->mode = TYPE;
529 break;
530 }
531
532 /* invalid code */
533 if (here.op & 64) {
534 strm->msg = (char *)"invalid literal/length code";
535 state->mode = BAD;
536 break;
537 }
538
539 /* length code -- get extra bits, if any */
540 state->extra = (unsigned)(here.op) & 15;
541 if (state->extra != 0) {
542 NEEDBITS(state->extra);
543 state->length += BITS(state->extra);
544 DROPBITS(state->extra);
545 }
546 Tracevv((stderr, "inflate: length %u\n", state->length));
547
548 /* get distance code */
549 for (;;) {
550 here = state->distcode[BITS(state->distbits)];
551 if ((unsigned)(here.bits) <= bits) break;
552 PULLBYTE();
553 }
554 if ((here.op & 0xf0) == 0) {
555 last = here;
556 for (;;) {
557 here = state->distcode[last.val +
558 (BITS(last.bits + last.op) >> last.bits)];
559 if ((unsigned)(last.bits + here.bits) <= bits) break;
560 PULLBYTE();
561 }
562 DROPBITS(last.bits);
563 }
564 DROPBITS(here.bits);
565 if (here.op & 64) {
566 strm->msg = (char *)"invalid distance code";
567 state->mode = BAD;
568 break;
569 }
570 state->offset = (unsigned)here.val;
571
572 /* get distance extra bits, if any */
573 state->extra = (unsigned)(here.op) & 15;
574 if (state->extra != 0) {
575 NEEDBITS(state->extra);
576 state->offset += BITS(state->extra);
577 DROPBITS(state->extra);
578 }
579 if (state->offset > state->wsize - (state->whave < state->wsize ?
580 left : 0)) {
581 strm->msg = (char *)"invalid distance too far back";
582 state->mode = BAD;
583 break;
584 }
585 Tracevv((stderr, "inflate: distance %u\n", state->offset));
586
587 /* copy match from window to output */
588 do {
589 ROOM();
590 copy = state->wsize - state->offset;
591 if (copy < left) {
592 from = put + copy;
593 copy = left - copy;
594 }
595 else {
596 from = put - state->offset;
597 copy = left;
598 }
599 if (copy > state->length) copy = state->length;
600 state->length -= copy;
601 left -= copy;
602 do {
603 *put++ = *from++;
604 } while (--copy);
605 } while (state->length != 0);
606 break;
607
608 case DONE:
609 /* inflate stream terminated properly */
610 ret = Z_STREAM_END;
611 goto inf_leave;
612
613 case BAD:
614 ret = Z_DATA_ERROR;
615 goto inf_leave;
616
617 default:
618 /* can't happen, but makes compilers happy */
619 ret = Z_STREAM_ERROR;
620 goto inf_leave;
621 }
622
623 /* Write leftover output and return unused input */
624 inf_leave:
625 if (left < state->wsize) {
626 if (out(out_desc, state->window, state->wsize - left) &&
627 ret == Z_STREAM_END)
628 ret = Z_BUF_ERROR;
629 }
630 strm->next_in = next;
631 strm->avail_in = have;
632 return ret;
633 }
634
635 int ZEXPORT inflateBackEnd(strm)
636 z_streamp strm;
637 {
638 if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
639 return Z_STREAM_ERROR;
640 ZFREE(strm, strm->state);
641 strm->state = Z_NULL;
642 Tracev((stderr, "inflate: end\n"));
643 return Z_OK;
644 }
645