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author | Mark Adler <madler@alumni.caltech.edu> | 2011-09-09 23:21:47 -0700 |
---|---|---|
committer | Mark Adler <madler@alumni.caltech.edu> | 2011-09-09 23:21:47 -0700 |
commit | 7c2a874e50b871d04fbd19501f7b42cff55e5abc (patch) | |
tree | 1879cd29182ababb17cde77cee5ce74505db4006 /infback.c | |
parent | a383133c4e7b93113cee912f213cf9502d785fa7 (diff) | |
download | zlib-7c2a874e50b871d04fbd19501f7b42cff55e5abc.tar.gz zlib-7c2a874e50b871d04fbd19501f7b42cff55e5abc.tar.bz2 zlib-7c2a874e50b871d04fbd19501f7b42cff55e5abc.zip |
zlib 1.2.0v1.2.0
Diffstat (limited to 'infback.c')
-rw-r--r-- | infback.c | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/infback.c b/infback.c new file mode 100644 index 0000000..46090ad --- /dev/null +++ b/infback.c | |||
@@ -0,0 +1,615 @@ | |||
1 | /* infback.c -- inflate using a call-back interface | ||
2 | * Copyright (C) 1995-2003 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_stream FAR *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 == Z_NULL) { | ||
45 | strm->zalloc = zcalloc; | ||
46 | strm->opaque = (voidpf)0; | ||
47 | } | ||
48 | if (strm->zfree == Z_NULL) strm->zfree = zcfree; | ||
49 | state = (struct inflate_state FAR *)ZALLOC(strm, 1, | ||
50 | sizeof(struct inflate_state)); | ||
51 | if (state == Z_NULL) return Z_MEM_ERROR; | ||
52 | Tracev((stderr, "inflate: allocated\n")); | ||
53 | strm->state = (voidpf)state; | ||
54 | state->wbits = windowBits; | ||
55 | state->wsize = 1U << windowBits; | ||
56 | state->window = window; | ||
57 | state->write = 0; | ||
58 | return Z_OK; | ||
59 | } | ||
60 | |||
61 | /* | ||
62 | Return state with length and distance decoding tables and index sizes set to | ||
63 | fixed code decoding. Normally this returns fixed tables from inffixed.h. | ||
64 | If BUILDFIXED is defined, then instead this routine builds the tables the | ||
65 | first time it's called, and returns those tables the first time and | ||
66 | thereafter. This reduces the size of the code by about 2K bytes, in | ||
67 | exchange for a little execution time. However, BUILDFIXED should not be | ||
68 | used for threaded applications, since the rewriting of the tables and virgin | ||
69 | may not be thread-safe. | ||
70 | */ | ||
71 | local void fixedtables(state) | ||
72 | struct inflate_state FAR *state; | ||
73 | { | ||
74 | #ifdef BUILDFIXED | ||
75 | static int virgin = 1; | ||
76 | static code *lenfix, *distfix; | ||
77 | static code fixed[544]; | ||
78 | |||
79 | /* build fixed huffman tables if first call (may not be thread safe) */ | ||
80 | if (virgin) { | ||
81 | unsigned sym, bits; | ||
82 | static code *next; | ||
83 | |||
84 | /* literal/length table */ | ||
85 | sym = 0; | ||
86 | while (sym < 144) state->lens[sym++] = 8; | ||
87 | while (sym < 256) state->lens[sym++] = 9; | ||
88 | while (sym < 280) state->lens[sym++] = 7; | ||
89 | while (sym < 288) state->lens[sym++] = 8; | ||
90 | next = fixed; | ||
91 | lenfix = next; | ||
92 | bits = 9; | ||
93 | inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work); | ||
94 | |||
95 | /* distance table */ | ||
96 | sym = 0; | ||
97 | while (sym < 32) state->lens[sym++] = 5; | ||
98 | distfix = next; | ||
99 | bits = 5; | ||
100 | inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work); | ||
101 | |||
102 | /* do this just once */ | ||
103 | virgin = 0; | ||
104 | } | ||
105 | #else /* !BUILDFIXED */ | ||
106 | # include "inffixed.h" | ||
107 | #endif /* BUILDFIXED */ | ||
108 | state->lencode = lenfix; | ||
109 | state->lenbits = 9; | ||
110 | state->distcode = distfix; | ||
111 | state->distbits = 5; | ||
112 | } | ||
113 | |||
114 | /* Macros for inflateBack(): */ | ||
115 | |||
116 | /* Load returned state from inflate_fast() */ | ||
117 | #define LOAD() \ | ||
118 | do { \ | ||
119 | put = strm->next_out; \ | ||
120 | left = strm->avail_out; \ | ||
121 | next = strm->next_in; \ | ||
122 | have = strm->avail_in; \ | ||
123 | hold = state->hold; \ | ||
124 | bits = state->bits; \ | ||
125 | } while (0) | ||
126 | |||
127 | /* Set state from registers for inflate_fast() */ | ||
128 | #define RESTORE() \ | ||
129 | do { \ | ||
130 | strm->next_out = put; \ | ||
131 | strm->avail_out = left; \ | ||
132 | strm->next_in = next; \ | ||
133 | strm->avail_in = have; \ | ||
134 | state->hold = hold; \ | ||
135 | state->bits = bits; \ | ||
136 | } while (0) | ||
137 | |||
138 | /* Clear the input bit accumulator */ | ||
139 | #define INITBITS() \ | ||
140 | do { \ | ||
141 | hold = 0; \ | ||
142 | bits = 0; \ | ||
143 | } while (0) | ||
144 | |||
145 | /* Assure that some input is available. If input is requested, but denied, | ||
146 | then return a Z_BUF_ERROR from inflateBack(). */ | ||
147 | #define PULL() \ | ||
148 | do { \ | ||
149 | if (have == 0) { \ | ||
150 | have = in(in_desc, &next); \ | ||
151 | if (have == 0) { \ | ||
152 | next = Z_NULL; \ | ||
153 | ret = Z_BUF_ERROR; \ | ||
154 | goto leave; \ | ||
155 | } \ | ||
156 | } \ | ||
157 | } while (0) | ||
158 | |||
159 | /* Get a byte of input into the bit accumulator, or return from inflateBack() | ||
160 | with an error if there is no input available. */ | ||
161 | #define PULLBYTE() \ | ||
162 | do { \ | ||
163 | PULL(); \ | ||
164 | have--; \ | ||
165 | hold += (unsigned long)(*next++) << bits; \ | ||
166 | bits += 8; \ | ||
167 | } while (0) | ||
168 | |||
169 | /* Assure that there are at least n bits in the bit accumulator. If there is | ||
170 | not enough available input to do that, then return from inflateBack() with | ||
171 | an error. */ | ||
172 | #define NEEDBITS(n) \ | ||
173 | do { \ | ||
174 | while (bits < (unsigned)(n)) \ | ||
175 | PULLBYTE(); \ | ||
176 | } while (0) | ||
177 | |||
178 | /* Return the low n bits of the bit accumulator (n < 16) */ | ||
179 | #define BITS(n) \ | ||
180 | ((unsigned)hold & ((1U << (n)) - 1)) | ||
181 | |||
182 | /* Remove n bits from the bit accumulator */ | ||
183 | #define DROPBITS(n) \ | ||
184 | do { \ | ||
185 | hold >>= (n); \ | ||
186 | bits -= (unsigned)(n); \ | ||
187 | } while (0) | ||
188 | |||
189 | /* Remove zero to seven bits as needed to go to a byte boundary */ | ||
190 | #define BYTEBITS() \ | ||
191 | do { \ | ||
192 | hold >>= bits & 7; \ | ||
193 | bits -= bits & 7; \ | ||
194 | } while (0) | ||
195 | |||
196 | /* Assure that some output space is available, by writing out the window | ||
197 | if it's full. If the write fails, return from inflateBack() with a | ||
198 | Z_BUF_ERROR. */ | ||
199 | #define ROOM() \ | ||
200 | do { \ | ||
201 | if (left == 0) { \ | ||
202 | put = state->window; \ | ||
203 | left = state->wsize; \ | ||
204 | if (out(out_desc, put, left)) { \ | ||
205 | ret = Z_BUF_ERROR; \ | ||
206 | goto leave; \ | ||
207 | } \ | ||
208 | } \ | ||
209 | } while (0) | ||
210 | |||
211 | /* | ||
212 | strm provides the memory allocation functions and window buffer on input, | ||
213 | and provides information on the unused input on return. For Z_DATA_ERROR | ||
214 | returns, strm will also provide an error message. | ||
215 | |||
216 | in() and out() are the call-back input and output functions. When | ||
217 | inflateBack() needs more input, it calls in(). When inflateBack() has | ||
218 | filled the window with output, or when it completes with data in the | ||
219 | window, it called out() to write out the data. The application must not | ||
220 | change the provided input until in() is called again or inflateBack() | ||
221 | returns. The application must not change the window/output buffer until | ||
222 | inflateBack() returns. | ||
223 | |||
224 | in() and out() are called with a descriptor parameter provided in the | ||
225 | inflateBack() call. This parameter can be a structure that provides the | ||
226 | information required to do the read or write, as well as accumulated | ||
227 | information on the input and output such as totals and check values. | ||
228 | |||
229 | in() should return zero on failure. out() should return non-zero on | ||
230 | failure. If either in() or out() fails, than inflateBack() returns a | ||
231 | Z_BUF_ERROR. strm->next_in can be checked for Z_NULL to see whether it | ||
232 | was in() or out() that caused in the error. Otherwise, inflateBack() | ||
233 | returns Z_STREAM_END on success, Z_DATA_ERROR for an deflate format | ||
234 | error, or Z_MEM_ERROR if it could not allocate memory for the state. | ||
235 | inflateBack() can also return Z_STREAM_ERROR if the input parameters | ||
236 | are not correct, i.e. strm is Z_NULL or the state was not initialized. | ||
237 | */ | ||
238 | int ZEXPORT inflateBack(strm, in, in_desc, out, out_desc) | ||
239 | z_stream FAR *strm; | ||
240 | in_func in; | ||
241 | void FAR *in_desc; | ||
242 | out_func out; | ||
243 | void FAR *out_desc; | ||
244 | { | ||
245 | struct inflate_state FAR *state; | ||
246 | unsigned char *next, *put; /* next input and output */ | ||
247 | unsigned have, left; /* available input and output */ | ||
248 | unsigned long hold; /* bit buffer */ | ||
249 | unsigned bits; /* bits in bit buffer */ | ||
250 | unsigned copy; /* number of stored or match bytes to copy */ | ||
251 | unsigned char *from; /* where to copy match bytes from */ | ||
252 | code this; /* current decoding table entry */ | ||
253 | code last; /* parent table entry */ | ||
254 | unsigned len; /* length to copy for repeats, bits to drop */ | ||
255 | int ret; /* return code */ | ||
256 | static const unsigned short order[19] = /* permutation of code lengths */ | ||
257 | {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15}; | ||
258 | |||
259 | /* Check that the strm exists and that the state was initialized */ | ||
260 | if (strm == Z_NULL || strm->state == Z_NULL) | ||
261 | return Z_STREAM_ERROR; | ||
262 | state = (struct inflate_state FAR *)strm->state; | ||
263 | |||
264 | /* Reset the state */ | ||
265 | strm->msg = Z_NULL; | ||
266 | state->mode = TYPE; | ||
267 | state->last = 0; | ||
268 | next = strm->next_in; | ||
269 | have = next != Z_NULL ? strm->avail_in : 0; | ||
270 | hold = 0; | ||
271 | bits = 0; | ||
272 | put = state->window; | ||
273 | left = state->wsize; | ||
274 | |||
275 | /* Inflate until end of block marked as last */ | ||
276 | for (;;) | ||
277 | switch (state->mode) { | ||
278 | case TYPE: | ||
279 | /* determine and dispatch block type */ | ||
280 | if (state->last) { | ||
281 | BYTEBITS(); | ||
282 | state->mode = DONE; | ||
283 | break; | ||
284 | } | ||
285 | NEEDBITS(3); | ||
286 | state->last = BITS(1); | ||
287 | DROPBITS(1); | ||
288 | switch (BITS(2)) { | ||
289 | case 0: /* stored block */ | ||
290 | Tracev((stderr, "inflate: stored block%s\n", | ||
291 | state->last ? " (last)" : "")); | ||
292 | state->mode = STORED; | ||
293 | break; | ||
294 | case 1: /* fixed block */ | ||
295 | fixedtables(state); | ||
296 | Tracev((stderr, "inflate: fixed codes block%s\n", | ||
297 | state->last ? " (last)" : "")); | ||
298 | state->mode = LEN; /* decode codes */ | ||
299 | break; | ||
300 | case 2: /* dynamic block */ | ||
301 | Tracev((stderr, "inflate: dynamic codes block%s\n", | ||
302 | state->last ? " (last)" : "")); | ||
303 | state->mode = TABLE; | ||
304 | break; | ||
305 | case 3: | ||
306 | strm->msg = (char *)"invalid block type"; | ||
307 | state->mode = BAD; | ||
308 | } | ||
309 | DROPBITS(2); | ||
310 | break; | ||
311 | |||
312 | case STORED: | ||
313 | /* get and verify stored block length */ | ||
314 | BYTEBITS(); /* go to byte boundary */ | ||
315 | NEEDBITS(32); | ||
316 | if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) { | ||
317 | strm->msg = (char *)"invalid stored block lengths"; | ||
318 | state->mode = BAD; | ||
319 | break; | ||
320 | } | ||
321 | state->length = (unsigned)hold & 0xffff; | ||
322 | Tracev((stderr, "inflate: stored length %u\n", | ||
323 | state->length)); | ||
324 | INITBITS(); | ||
325 | |||
326 | /* copy stored block from input to output */ | ||
327 | while (state->length != 0) { | ||
328 | copy = state->length; | ||
329 | PULL(); | ||
330 | ROOM(); | ||
331 | if (copy > have) copy = have; | ||
332 | if (copy > left) copy = left; | ||
333 | zmemcpy(put, next, copy); | ||
334 | have -= copy; | ||
335 | next += copy; | ||
336 | left -= copy; | ||
337 | put += copy; | ||
338 | state->length -= copy; | ||
339 | } | ||
340 | Tracev((stderr, "inflate: stored end\n")); | ||
341 | state->mode = TYPE; | ||
342 | break; | ||
343 | |||
344 | case TABLE: | ||
345 | /* get dynamic table entries descriptor */ | ||
346 | NEEDBITS(14); | ||
347 | state->nlen = BITS(5) + 257; | ||
348 | DROPBITS(5); | ||
349 | state->ndist = BITS(5) + 1; | ||
350 | DROPBITS(5); | ||
351 | state->ncode = BITS(4) + 4; | ||
352 | DROPBITS(4); | ||
353 | #ifndef PKZIP_BUG_WORKAROUND | ||
354 | if (state->nlen > 286 || state->ndist > 30) { | ||
355 | strm->msg = (char *)"too many length or distance symbols"; | ||
356 | state->mode = BAD; | ||
357 | break; | ||
358 | } | ||
359 | #endif | ||
360 | Tracev((stderr, "inflate: table sizes ok\n")); | ||
361 | |||
362 | /* get code length code lengths (not a typo) */ | ||
363 | state->have = 0; | ||
364 | while (state->have < state->ncode) { | ||
365 | NEEDBITS(3); | ||
366 | state->lens[order[state->have++]] = (unsigned short)BITS(3); | ||
367 | DROPBITS(3); | ||
368 | } | ||
369 | while (state->have < 19) | ||
370 | state->lens[order[state->have++]] = 0; | ||
371 | state->next = state->codes; | ||
372 | state->lencode = (code const FAR *)(state->next); | ||
373 | state->lenbits = 7; | ||
374 | ret = inflate_table(CODES, state->lens, 19, &(state->next), | ||
375 | &(state->lenbits), state->work); | ||
376 | if (ret) { | ||
377 | strm->msg = (char *)"invalid code lengths set"; | ||
378 | state->mode = BAD; | ||
379 | break; | ||
380 | } | ||
381 | Tracev((stderr, "inflate: code lengths ok\n")); | ||
382 | |||
383 | /* get length and distance code code lengths */ | ||
384 | state->have = 0; | ||
385 | while (state->have < state->nlen + state->ndist) { | ||
386 | for (;;) { | ||
387 | this = state->lencode[BITS(state->lenbits)]; | ||
388 | if ((unsigned)(this.bits) <= bits) break; | ||
389 | PULLBYTE(); | ||
390 | } | ||
391 | if (this.val < 16) { | ||
392 | NEEDBITS(this.bits); | ||
393 | DROPBITS(this.bits); | ||
394 | state->lens[state->have++] = this.val; | ||
395 | } | ||
396 | else { | ||
397 | if (this.val == 16) { | ||
398 | NEEDBITS(this.bits + 2); | ||
399 | DROPBITS(this.bits); | ||
400 | if (state->have == 0) { | ||
401 | strm->msg = (char *)"invalid bit length repeat"; | ||
402 | state->mode = BAD; | ||
403 | break; | ||
404 | } | ||
405 | len = (unsigned)(state->lens[state->have - 1]); | ||
406 | copy = 3 + BITS(2); | ||
407 | DROPBITS(2); | ||
408 | } | ||
409 | else if (this.val == 17) { | ||
410 | NEEDBITS(this.bits + 3); | ||
411 | DROPBITS(this.bits); | ||
412 | len = 0; | ||
413 | copy = 3 + BITS(3); | ||
414 | DROPBITS(3); | ||
415 | } | ||
416 | else { | ||
417 | NEEDBITS(this.bits + 7); | ||
418 | DROPBITS(this.bits); | ||
419 | len = 0; | ||
420 | copy = 11 + BITS(7); | ||
421 | DROPBITS(7); | ||
422 | } | ||
423 | if (state->have + copy > state->nlen + state->ndist) { | ||
424 | strm->msg = (char *)"invalid bit length repeat"; | ||
425 | state->mode = BAD; | ||
426 | break; | ||
427 | } | ||
428 | while (copy--) | ||
429 | state->lens[state->have++] = (unsigned short)len; | ||
430 | } | ||
431 | } | ||
432 | |||
433 | /* build code tables */ | ||
434 | state->next = state->codes; | ||
435 | state->lencode = (code const FAR *)(state->next); | ||
436 | state->lenbits = 9; | ||
437 | ret = inflate_table(LENS, state->lens, state->nlen, &(state->next), | ||
438 | &(state->lenbits), state->work); | ||
439 | if (ret) { | ||
440 | strm->msg = (char *)"invalid literal/lengths set"; | ||
441 | state->mode = BAD; | ||
442 | break; | ||
443 | } | ||
444 | state->distcode = (code const FAR *)(state->next); | ||
445 | state->distbits = 6; | ||
446 | ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist, | ||
447 | &(state->next), &(state->distbits), state->work); | ||
448 | if (ret) { | ||
449 | strm->msg = (char *)"invalid distances set"; | ||
450 | state->mode = BAD; | ||
451 | break; | ||
452 | } | ||
453 | Tracev((stderr, "inflate: codes ok\n")); | ||
454 | state->mode = LEN; | ||
455 | |||
456 | case LEN: | ||
457 | /* use inflate_fast() if we have enough input and output */ | ||
458 | if (have >= 6 && left >= 258) { | ||
459 | RESTORE(); | ||
460 | inflate_fast(strm, state->wsize); | ||
461 | LOAD(); | ||
462 | break; | ||
463 | } | ||
464 | |||
465 | /* get a literal, length, or end-of-block code */ | ||
466 | for (;;) { | ||
467 | this = state->lencode[BITS(state->lenbits)]; | ||
468 | if ((unsigned)(this.bits) <= bits) break; | ||
469 | PULLBYTE(); | ||
470 | } | ||
471 | if (this.op && (this.op & 0xf0) == 0) { | ||
472 | last = this; | ||
473 | for (;;) { | ||
474 | this = state->lencode[last.val + | ||
475 | (BITS(last.bits + last.op) >> last.bits)]; | ||
476 | if ((unsigned)(last.bits + this.bits) <= bits) break; | ||
477 | PULLBYTE(); | ||
478 | } | ||
479 | DROPBITS(last.bits); | ||
480 | } | ||
481 | DROPBITS(this.bits); | ||
482 | state->length = (unsigned)this.val; | ||
483 | |||
484 | /* process literal */ | ||
485 | if (this.op == 0) { | ||
486 | Tracevv((stderr, this.val >= 0x20 && this.val < 0x7f ? | ||
487 | "inflate: literal '%c'\n" : | ||
488 | "inflate: literal 0x%02x\n", this.val)); | ||
489 | ROOM(); | ||
490 | *put++ = (unsigned char)(state->length); | ||
491 | left--; | ||
492 | state->mode = LEN; | ||
493 | break; | ||
494 | } | ||
495 | |||
496 | /* process end of block */ | ||
497 | if (this.op & 32) { | ||
498 | Tracevv((stderr, "inflate: end of block\n")); | ||
499 | state->mode = TYPE; | ||
500 | break; | ||
501 | } | ||
502 | |||
503 | /* invalid code */ | ||
504 | if (this.op & 64) { | ||
505 | strm->msg = (char *)"invalid literal/length code"; | ||
506 | state->mode = BAD; | ||
507 | break; | ||
508 | } | ||
509 | |||
510 | /* length code -- get extra bits, if any */ | ||
511 | state->extra = (unsigned)(this.op) & 15; | ||
512 | if (state->extra != 0) { | ||
513 | NEEDBITS(state->extra); | ||
514 | state->length += BITS(state->extra); | ||
515 | DROPBITS(state->extra); | ||
516 | } | ||
517 | Tracevv((stderr, "inflate: length %u\n", state->length)); | ||
518 | |||
519 | /* get distance code */ | ||
520 | for (;;) { | ||
521 | this = state->distcode[BITS(state->distbits)]; | ||
522 | if ((unsigned)(this.bits) <= bits) break; | ||
523 | PULLBYTE(); | ||
524 | } | ||
525 | if ((this.op & 0xf0) == 0) { | ||
526 | last = this; | ||
527 | for (;;) { | ||
528 | this = state->distcode[last.val + | ||
529 | (BITS(last.bits + last.op) >> last.bits)]; | ||
530 | if ((unsigned)(last.bits + this.bits) <= bits) break; | ||
531 | PULLBYTE(); | ||
532 | } | ||
533 | DROPBITS(last.bits); | ||
534 | } | ||
535 | DROPBITS(this.bits); | ||
536 | if (this.op & 64) { | ||
537 | strm->msg = (char *)"invalid distance code"; | ||
538 | state->mode = BAD; | ||
539 | break; | ||
540 | } | ||
541 | state->offset = (unsigned)this.val; | ||
542 | |||
543 | /* get distance extra bits, if any */ | ||
544 | state->extra = (unsigned)(this.op) & 15; | ||
545 | if (state->extra != 0) { | ||
546 | NEEDBITS(state->extra); | ||
547 | state->offset += BITS(state->extra); | ||
548 | DROPBITS(state->extra); | ||
549 | } | ||
550 | if (state->offset > state->wsize) { | ||
551 | strm->msg = (char *)"invalid distance too far back"; | ||
552 | state->mode = BAD; | ||
553 | break; | ||
554 | } | ||
555 | Tracevv((stderr, "inflate: distance %u\n", state->offset)); | ||
556 | |||
557 | /* copy match from window to output */ | ||
558 | do { | ||
559 | ROOM(); | ||
560 | copy = state->wsize - state->offset; | ||
561 | if (copy < left) { | ||
562 | from = put + copy; | ||
563 | copy = left - copy; | ||
564 | } | ||
565 | else { | ||
566 | from = put - state->offset; | ||
567 | copy = left; | ||
568 | } | ||
569 | if (copy > state->length) copy = state->length; | ||
570 | state->length -= copy; | ||
571 | left -= copy; | ||
572 | do { | ||
573 | *put++ = *from++; | ||
574 | } while (--copy); | ||
575 | } while (state->length != 0); | ||
576 | break; | ||
577 | |||
578 | case DONE: | ||
579 | /* inflate stream terminated properly -- write leftover output */ | ||
580 | ret = Z_STREAM_END; | ||
581 | if (left < state->wsize) { | ||
582 | if (out(out_desc, state->window, state->wsize - left)) | ||
583 | ret = Z_BUF_ERROR; | ||
584 | } | ||
585 | goto leave; | ||
586 | |||
587 | case BAD: | ||
588 | ret = Z_DATA_ERROR; | ||
589 | goto leave; | ||
590 | |||
591 | default: /* can't happen, but makes compilers happy */ | ||
592 | ret = Z_STREAM_ERROR; | ||
593 | goto leave; | ||
594 | } | ||
595 | |||
596 | /* Return unused input */ | ||
597 | leave: | ||
598 | strm->next_in = next; | ||
599 | strm->avail_in = have; | ||
600 | return ret; | ||
601 | } | ||
602 | |||
603 | int ZEXPORT inflateBackEnd(strm) | ||
604 | z_stream FAR *strm; | ||
605 | { | ||
606 | struct inflate_state FAR *state; | ||
607 | |||
608 | if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == Z_NULL) | ||
609 | return Z_STREAM_ERROR; | ||
610 | state = (struct inflate_state FAR *)strm->state; | ||
611 | ZFREE(strm, strm->state); | ||
612 | strm->state = Z_NULL; | ||
613 | Tracev((stderr, "inflate: end\n")); | ||
614 | return Z_OK; | ||
615 | } | ||