1: /* infback.c -- inflate using a call-back interface
2: * Copyright (C) 1995-2009 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: strm->zalloc = zcalloc;
46: strm->opaque = (voidpf)0;
47: }
48: if (strm->zfree == (free_func)0) 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 = (struct internal_state FAR *)state;
54: state->dmax = 32768U;
55: state->wbits = windowBits;
56: state->wsize = 1U << windowBits;
57: state->window = window;
58: state->wnext = 0;
59: state->whave = 0;
60: return Z_OK;
61: }
62:
63: /*
64: Return state with length and distance decoding tables and index sizes set to
65: fixed code decoding. Normally this returns fixed tables from inffixed.h.
66: If BUILDFIXED is defined, then instead this routine builds the tables the
67: first time it's called, and returns those tables the first time and
68: thereafter. This reduces the size of the code by about 2K bytes, in
69: exchange for a little execution time. However, BUILDFIXED should not be
70: used for threaded applications, since the rewriting of the tables and virgin
71: may not be thread-safe.
72: */
73: local void fixedtables(state)
74: struct inflate_state FAR *state;
75: {
76: #ifdef BUILDFIXED
77: static int virgin = 1;
78: static code *lenfix, *distfix;
79: static code fixed[544];
80:
81: /* build fixed huffman tables if first call (may not be thread safe) */
82: if (virgin) {
83: unsigned sym, bits;
84: static code *next;
85:
86: /* literal/length table */
87: sym = 0;
88: while (sym < 144) state->lens[sym++] = 8;
89: while (sym < 256) state->lens[sym++] = 9;
90: while (sym < 280) state->lens[sym++] = 7;
91: while (sym < 288) state->lens[sym++] = 8;
92: next = fixed;
93: lenfix = next;
94: bits = 9;
95: inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
96:
97: /* distance table */
98: sym = 0;
99: while (sym < 32) state->lens[sym++] = 5;
100: distfix = next;
101: bits = 5;
102: inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
103:
104: /* do this just once */
105: virgin = 0;
106: }
107: #else /* !BUILDFIXED */
108: # include "inffixed.h"
109: #endif /* BUILDFIXED */
110: state->lencode = lenfix;
111: state->lenbits = 9;
112: state->distcode = distfix;
113: state->distbits = 5;
114: }
115:
116: /* Macros for inflateBack(): */
117:
118: /* Load returned state from inflate_fast() */
119: #define LOAD() \
120: do { \
121: put = strm->next_out; \
122: left = strm->avail_out; \
123: next = strm->next_in; \
124: have = strm->avail_in; \
125: hold = state->hold; \
126: bits = state->bits; \
127: } while (0)
128:
129: /* Set state from registers for inflate_fast() */
130: #define RESTORE() \
131: do { \
132: strm->next_out = put; \
133: strm->avail_out = left; \
134: strm->next_in = next; \
135: strm->avail_in = have; \
136: state->hold = hold; \
137: state->bits = bits; \
138: } while (0)
139:
140: /* Clear the input bit accumulator */
141: #define INITBITS() \
142: do { \
143: hold = 0; \
144: bits = 0; \
145: } while (0)
146:
147: /* Assure that some input is available. If input is requested, but denied,
148: then return a Z_BUF_ERROR from inflateBack(). */
149: #define PULL() \
150: do { \
151: if (have == 0) { \
152: have = in(in_desc, &next); \
153: if (have == 0) { \
154: next = Z_NULL; \
155: ret = Z_BUF_ERROR; \
156: goto inf_leave; \
157: } \
158: } \
159: } while (0)
160:
161: /* Get a byte of input into the bit accumulator, or return from inflateBack()
162: with an error if there is no input available. */
163: #define PULLBYTE() \
164: do { \
165: PULL(); \
166: have--; \
167: hold += (unsigned long)(*next++) << bits; \
168: bits += 8; \
169: } while (0)
170:
171: /* Assure that there are at least n bits in the bit accumulator. If there is
172: not enough available input to do that, then return from inflateBack() with
173: an error. */
174: #define NEEDBITS(n) \
175: do { \
176: while (bits < (unsigned)(n)) \
177: PULLBYTE(); \
178: } while (0)
179:
180: /* Return the low n bits of the bit accumulator (n < 16) */
181: #define BITS(n) \
182: ((unsigned)hold & ((1U << (n)) - 1))
183:
184: /* Remove n bits from the bit accumulator */
185: #define DROPBITS(n) \
186: do { \
187: hold >>= (n); \
188: bits -= (unsigned)(n); \
189: } while (0)
190:
191: /* Remove zero to seven bits as needed to go to a byte boundary */
192: #define BYTEBITS() \
193: do { \
194: hold >>= bits & 7; \
195: bits -= bits & 7; \
196: } while (0)
197:
198: /* Assure that some output space is available, by writing out the window
199: if it's full. If the write fails, return from inflateBack() with a
200: Z_BUF_ERROR. */
201: #define ROOM() \
202: do { \
203: if (left == 0) { \
204: put = state->window; \
205: left = state->wsize; \
206: state->whave = left; \
207: if (out(out_desc, put, left)) { \
208: ret = Z_BUF_ERROR; \
209: goto inf_leave; \
210: } \
211: } \
212: } while (0)
213:
214: /*
215: strm provides the memory allocation functions and window buffer on input,
216: and provides information on the unused input on return. For Z_DATA_ERROR
217: returns, strm will also provide an error message.
218:
219: in() and out() are the call-back input and output functions. When
220: inflateBack() needs more input, it calls in(). When inflateBack() has
221: filled the window with output, or when it completes with data in the
222: window, it calls out() to write out the data. The application must not
223: change the provided input until in() is called again or inflateBack()
224: returns. The application must not change the window/output buffer until
225: inflateBack() returns.
226:
227: in() and out() are called with a descriptor parameter provided in the
228: inflateBack() call. This parameter can be a structure that provides the
229: information required to do the read or write, as well as accumulated
230: information on the input and output such as totals and check values.
231:
232: in() should return zero on failure. out() should return non-zero on
233: failure. If either in() or out() fails, than inflateBack() returns a
234: Z_BUF_ERROR. strm->next_in can be checked for Z_NULL to see whether it
235: was in() or out() that caused in the error. Otherwise, inflateBack()
236: returns Z_STREAM_END on success, Z_DATA_ERROR for an deflate format
237: error, or Z_MEM_ERROR if it could not allocate memory for the state.
238: inflateBack() can also return Z_STREAM_ERROR if the input parameters
239: are not correct, i.e. strm is Z_NULL or the state was not initialized.
240: */
241: int ZEXPORT inflateBack(strm, in, in_desc, out, out_desc)
242: z_streamp strm;
243: in_func in;
244: void FAR *in_desc;
245: out_func out;
246: void FAR *out_desc;
247: {
248: struct inflate_state FAR *state;
249: unsigned char FAR *next; /* next input */
250: unsigned char FAR *put; /* next output */
251: unsigned have, left; /* available input and output */
252: unsigned long hold; /* bit buffer */
253: unsigned bits; /* bits in bit buffer */
254: unsigned copy; /* number of stored or match bytes to copy */
255: unsigned char FAR *from; /* where to copy match bytes from */
256: code here; /* current decoding table entry */
257: code last; /* parent table entry */
258: unsigned len; /* length to copy for repeats, bits to drop */
259: int ret; /* return code */
260: static const unsigned short order[19] = /* permutation of code lengths */
261: {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
262:
263: /* Check that the strm exists and that the state was initialized */
264: if (strm == Z_NULL || strm->state == Z_NULL)
265: return Z_STREAM_ERROR;
266: state = (struct inflate_state FAR *)strm->state;
267:
268: /* Reset the state */
269: strm->msg = Z_NULL;
270: state->mode = TYPE;
271: state->last = 0;
272: state->whave = 0;
273: next = strm->next_in;
274: have = next != Z_NULL ? strm->avail_in : 0;
275: hold = 0;
276: bits = 0;
277: put = state->window;
278: left = state->wsize;
279:
280: /* Inflate until end of block marked as last */
281: for (;;)
282: switch (state->mode) {
283: case TYPE:
284: /* determine and dispatch block type */
285: if (state->last) {
286: BYTEBITS();
287: state->mode = DONE;
288: break;
289: }
290: NEEDBITS(3);
291: state->last = BITS(1);
292: DROPBITS(1);
293: switch (BITS(2)) {
294: case 0: /* stored block */
295: Tracev((stderr, "inflate: stored block%s\n",
296: state->last ? " (last)" : ""));
297: state->mode = STORED;
298: break;
299: case 1: /* fixed block */
300: fixedtables(state);
301: Tracev((stderr, "inflate: fixed codes block%s\n",
302: state->last ? " (last)" : ""));
303: state->mode = LEN; /* decode codes */
304: break;
305: case 2: /* dynamic block */
306: Tracev((stderr, "inflate: dynamic codes block%s\n",
307: state->last ? " (last)" : ""));
308: state->mode = TABLE;
309: break;
310: case 3:
311: strm->msg = (char *)"invalid block type";
312: state->mode = BAD;
313: }
314: DROPBITS(2);
315: break;
316:
317: case STORED:
318: /* get and verify stored block length */
319: BYTEBITS(); /* go to byte boundary */
320: NEEDBITS(32);
321: if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
322: strm->msg = (char *)"invalid stored block lengths";
323: state->mode = BAD;
324: break;
325: }
326: state->length = (unsigned)hold & 0xffff;
327: Tracev((stderr, "inflate: stored length %u\n",
328: state->length));
329: INITBITS();
330:
331: /* copy stored block from input to output */
332: while (state->length != 0) {
333: copy = state->length;
334: PULL();
335: ROOM();
336: if (copy > have) copy = have;
337: if (copy > left) copy = left;
338: zmemcpy(put, next, copy);
339: have -= copy;
340: next += copy;
341: left -= copy;
342: put += copy;
343: state->length -= copy;
344: }
345: Tracev((stderr, "inflate: stored end\n"));
346: state->mode = TYPE;
347: break;
348:
349: case TABLE:
350: /* get dynamic table entries descriptor */
351: NEEDBITS(14);
352: state->nlen = BITS(5) + 257;
353: DROPBITS(5);
354: state->ndist = BITS(5) + 1;
355: DROPBITS(5);
356: state->ncode = BITS(4) + 4;
357: DROPBITS(4);
358: #ifndef PKZIP_BUG_WORKAROUND
359: if (state->nlen > 286 || state->ndist > 30) {
360: strm->msg = (char *)"too many length or distance symbols";
361: state->mode = BAD;
362: break;
363: }
364: #endif
365: Tracev((stderr, "inflate: table sizes ok\n"));
366:
367: /* get code length code lengths (not a typo) */
368: state->have = 0;
369: while (state->have < state->ncode) {
370: NEEDBITS(3);
371: state->lens[order[state->have++]] = (unsigned short)BITS(3);
372: DROPBITS(3);
373: }
374: while (state->have < 19)
375: state->lens[order[state->have++]] = 0;
376: state->next = state->codes;
377: state->lencode = (code const FAR *)(state->next);
378: state->lenbits = 7;
379: ret = inflate_table(CODES, state->lens, 19, &(state->next),
380: &(state->lenbits), state->work);
381: if (ret) {
382: strm->msg = (char *)"invalid code lengths set";
383: state->mode = BAD;
384: break;
385: }
386: Tracev((stderr, "inflate: code lengths ok\n"));
387:
388: /* get length and distance code code lengths */
389: state->have = 0;
390: while (state->have < state->nlen + state->ndist) {
391: for (;;) {
392: here = state->lencode[BITS(state->lenbits)];
393: if ((unsigned)(here.bits) <= bits) break;
394: PULLBYTE();
395: }
396: if (here.val < 16) {
397: NEEDBITS(here.bits);
398: DROPBITS(here.bits);
399: state->lens[state->have++] = here.val;
400: }
401: else {
402: if (here.val == 16) {
403: NEEDBITS(here.bits + 2);
404: DROPBITS(here.bits);
405: if (state->have == 0) {
406: strm->msg = (char *)"invalid bit length repeat";
407: state->mode = BAD;
408: break;
409: }
410: len = (unsigned)(state->lens[state->have - 1]);
411: copy = 3 + BITS(2);
412: DROPBITS(2);
413: }
414: else if (here.val == 17) {
415: NEEDBITS(here.bits + 3);
416: DROPBITS(here.bits);
417: len = 0;
418: copy = 3 + BITS(3);
419: DROPBITS(3);
420: }
421: else {
422: NEEDBITS(here.bits + 7);
423: DROPBITS(here.bits);
424: len = 0;
425: copy = 11 + BITS(7);
426: DROPBITS(7);
427: }
428: if (state->have + copy > state->nlen + state->ndist) {
429: strm->msg = (char *)"invalid bit length repeat";
430: state->mode = BAD;
431: break;
432: }
433: while (copy--)
434: state->lens[state->have++] = (unsigned short)len;
435: }
436: }
437:
438: /* handle error breaks in while */
439: if (state->mode == BAD) break;
440:
441: /* check for end-of-block code (better have one) */
442: if (state->lens[256] == 0) {
443: strm->msg = (char *)"invalid code -- missing end-of-block";
444: state->mode = BAD;
445: break;
446: }
447:
448: /* build code tables -- note: do not change the lenbits or distbits
449: values here (9 and 6) without reading the comments in inftrees.h
450: concerning the ENOUGH constants, which depend on those values */
451: state->next = state->codes;
452: state->lencode = (code const FAR *)(state->next);
453: state->lenbits = 9;
454: ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
455: &(state->lenbits), state->work);
456: if (ret) {
457: strm->msg = (char *)"invalid literal/lengths set";
458: state->mode = BAD;
459: break;
460: }
461: state->distcode = (code const FAR *)(state->next);
462: state->distbits = 6;
463: ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
464: &(state->next), &(state->distbits), state->work);
465: if (ret) {
466: strm->msg = (char *)"invalid distances set";
467: state->mode = BAD;
468: break;
469: }
470: Tracev((stderr, "inflate: codes ok\n"));
471: state->mode = LEN;
472:
473: case LEN:
474: /* use inflate_fast() if we have enough input and output */
475: if (have >= 6 && left >= 258) {
476: RESTORE();
477: if (state->whave < state->wsize)
478: state->whave = state->wsize - left;
479: inflate_fast(strm, state->wsize);
480: LOAD();
481: break;
482: }
483:
484: /* get a literal, length, or end-of-block code */
485: for (;;) {
486: here = state->lencode[BITS(state->lenbits)];
487: if ((unsigned)(here.bits) <= bits) break;
488: PULLBYTE();
489: }
490: if (here.op && (here.op & 0xf0) == 0) {
491: last = here;
492: for (;;) {
493: here = state->lencode[last.val +
494: (BITS(last.bits + last.op) >> last.bits)];
495: if ((unsigned)(last.bits + here.bits) <= bits) break;
496: PULLBYTE();
497: }
498: DROPBITS(last.bits);
499: }
500: DROPBITS(here.bits);
501: state->length = (unsigned)here.val;
502:
503: /* process literal */
504: if (here.op == 0) {
505: Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
506: "inflate: literal '%c'\n" :
507: "inflate: literal 0x%02x\n", here.val));
508: ROOM();
509: *put++ = (unsigned char)(state->length);
510: left--;
511: state->mode = LEN;
512: break;
513: }
514:
515: /* process end of block */
516: if (here.op & 32) {
517: Tracevv((stderr, "inflate: end of block\n"));
518: state->mode = TYPE;
519: break;
520: }
521:
522: /* invalid code */
523: if (here.op & 64) {
524: strm->msg = (char *)"invalid literal/length code";
525: state->mode = BAD;
526: break;
527: }
528:
529: /* length code -- get extra bits, if any */
530: state->extra = (unsigned)(here.op) & 15;
531: if (state->extra != 0) {
532: NEEDBITS(state->extra);
533: state->length += BITS(state->extra);
534: DROPBITS(state->extra);
535: }
536: Tracevv((stderr, "inflate: length %u\n", state->length));
537:
538: /* get distance code */
539: for (;;) {
540: here = state->distcode[BITS(state->distbits)];
541: if ((unsigned)(here.bits) <= bits) break;
542: PULLBYTE();
543: }
544: if ((here.op & 0xf0) == 0) {
545: last = here;
546: for (;;) {
547: here = state->distcode[last.val +
548: (BITS(last.bits + last.op) >> last.bits)];
549: if ((unsigned)(last.bits + here.bits) <= bits) break;
550: PULLBYTE();
551: }
552: DROPBITS(last.bits);
553: }
554: DROPBITS(here.bits);
555: if (here.op & 64) {
556: strm->msg = (char *)"invalid distance code";
557: state->mode = BAD;
558: break;
559: }
560: state->offset = (unsigned)here.val;
561:
562: /* get distance extra bits, if any */
563: state->extra = (unsigned)(here.op) & 15;
564: if (state->extra != 0) {
565: NEEDBITS(state->extra);
566: state->offset += BITS(state->extra);
567: DROPBITS(state->extra);
568: }
569: if (state->offset > state->wsize - (state->whave < state->wsize ?
570: left : 0)) {
571: strm->msg = (char *)"invalid distance too far back";
572: state->mode = BAD;
573: break;
574: }
575: Tracevv((stderr, "inflate: distance %u\n", state->offset));
576:
577: /* copy match from window to output */
578: do {
579: ROOM();
580: copy = state->wsize - state->offset;
581: if (copy < left) {
582: from = put + copy;
583: copy = left - copy;
584: }
585: else {
586: from = put - state->offset;
587: copy = left;
588: }
589: if (copy > state->length) copy = state->length;
590: state->length -= copy;
591: left -= copy;
592: do {
593: *put++ = *from++;
594: } while (--copy);
595: } while (state->length != 0);
596: break;
597:
598: case DONE:
599: /* inflate stream terminated properly -- write leftover output */
600: ret = Z_STREAM_END;
601: if (left < state->wsize) {
602: if (out(out_desc, state->window, state->wsize - left))
603: ret = Z_BUF_ERROR;
604: }
605: goto inf_leave;
606:
607: case BAD:
608: ret = Z_DATA_ERROR;
609: goto inf_leave;
610:
611: default: /* can't happen, but makes compilers happy */
612: ret = Z_STREAM_ERROR;
613: goto inf_leave;
614: }
615:
616: /* Return unused input */
617: inf_leave:
618: strm->next_in = next;
619: strm->avail_in = have;
620: return ret;
621: }
622:
623: int ZEXPORT inflateBackEnd(strm)
624: z_streamp strm;
625: {
626: if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
627: return Z_STREAM_ERROR;
628: ZFREE(strm, strm->state);
629: strm->state = Z_NULL;
630: Tracev((stderr, "inflate: end\n"));
631: return Z_OK;
632: }
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