1
/* infback.c -- inflate using a call-back interface
2
* Copyright (C) 1995-2005 Mark Adler
3
* For conditions of distribution and use, see copyright notice in zlib.h
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.
18
/* function prototypes */
19
local void fixedtables OF((struct inflate_state FAR *state));
22
strm provides memory allocation functions in zalloc and zfree, or
23
Z_NULL to use the library memory allocation functions.
25
windowBits is in the range 8..15, and window is a user-supplied
26
window and output buffer that is 2**windowBits bytes.
28
int ZEXPORT inflateBackInit_(strm, windowBits, window, version, stream_size)
31
unsigned char FAR *window;
35
struct inflate_state FAR *state;
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;
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;
55
state->wbits = windowBits;
56
state->wsize = 1U << windowBits;
57
state->window = window;
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.
73
local void fixedtables(state)
74
struct inflate_state FAR *state;
77
static int virgin = 1;
78
static code *lenfix, *distfix;
79
static code fixed[544];
81
/* build fixed huffman tables if first call (may not be thread safe) */
86
/* literal/length table */
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;
95
inflate_table(LENS, state->lens, 288, &(next), &(bits), state->work);
99
while (sym < 32) state->lens[sym++] = 5;
102
inflate_table(DISTS, state->lens, 32, &(next), &(bits), state->work);
104
/* do this just once */
107
#else /* !BUILDFIXED */
108
# include "inffixed.h"
109
#endif /* BUILDFIXED */
110
state->lencode = lenfix;
112
state->distcode = distfix;
116
/* Macros for inflateBack(): */
118
/* Load returned state from inflate_fast() */
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; \
129
/* Set state from registers for inflate_fast() */
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; \
140
/* Clear the input bit accumulator */
147
/* Assure that some input is available. If input is requested, but denied,
148
then return a Z_BUF_ERROR from inflateBack(). */
152
have = in(in_desc, &next); \
161
/* Get a byte of input into the bit accumulator, or return from inflateBack()
162
with an error if there is no input available. */
167
hold += (unsigned long)(*next++) << bits; \
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
174
#define NEEDBITS(n) \
176
while (bits < (unsigned)(n)) \
180
/* Return the low n bits of the bit accumulator (n < 16) */
182
((unsigned)hold & ((1U << (n)) - 1))
184
/* Remove n bits from the bit accumulator */
185
#define DROPBITS(n) \
188
bits -= (unsigned)(n); \
191
/* Remove zero to seven bits as needed to go to a byte boundary */
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
204
put = state->window; \
205
left = state->wsize; \
206
state->whave = left; \
207
if (out(out_desc, put, left)) { \
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.
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.
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.
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.
241
int ZEXPORT inflateBack(strm, in, in_desc, out, out_desc)
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 this; /* 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};
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;
268
/* Reset the state */
273
next = strm->next_in;
274
have = next != Z_NULL ? strm->avail_in : 0;
280
/* Inflate until end of block marked as last */
282
switch (state->mode) {
284
/* determine and dispatch block type */
291
state->last = BITS(1);
294
case 0: /* stored block */
295
Tracev((stderr, "inflate: stored block%s\n",
296
state->last ? " (last)" : ""));
297
state->mode = STORED;
299
case 1: /* fixed block */
301
Tracev((stderr, "inflate: fixed codes block%s\n",
302
state->last ? " (last)" : ""));
303
state->mode = LEN; /* decode codes */
305
case 2: /* dynamic block */
306
Tracev((stderr, "inflate: dynamic codes block%s\n",
307
state->last ? " (last)" : ""));
311
strm->msg = (char *)"invalid block type";
318
/* get and verify stored block length */
319
BYTEBITS(); /* go to byte boundary */
321
if ((hold & 0xffff) != ((hold >> 16) ^ 0xffff)) {
322
strm->msg = (char *)"invalid stored block lengths";
326
state->length = (unsigned)hold & 0xffff;
327
Tracev((stderr, "inflate: stored length %u\n",
331
/* copy stored block from input to output */
332
while (state->length != 0) {
333
copy = state->length;
336
if (copy > have) copy = have;
337
if (copy > left) copy = left;
338
zmemcpy(put, next, copy);
343
state->length -= copy;
345
Tracev((stderr, "inflate: stored end\n"));
350
/* get dynamic table entries descriptor */
352
state->nlen = BITS(5) + 257;
354
state->ndist = BITS(5) + 1;
356
state->ncode = BITS(4) + 4;
358
#ifndef PKZIP_BUG_WORKAROUND
359
if (state->nlen > 286 || state->ndist > 30) {
360
strm->msg = (char *)"too many length or distance symbols";
365
Tracev((stderr, "inflate: table sizes ok\n"));
367
/* get code length code lengths (not a typo) */
369
while (state->have < state->ncode) {
371
state->lens[order[state->have++]] = (unsigned short)BITS(3);
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);
379
ret = inflate_table(CODES, state->lens, 19, &(state->next),
380
&(state->lenbits), state->work);
382
strm->msg = (char *)"invalid code lengths set";
386
Tracev((stderr, "inflate: code lengths ok\n"));
388
/* get length and distance code code lengths */
390
while (state->have < state->nlen + state->ndist) {
392
this = state->lencode[BITS(state->lenbits)];
393
if ((unsigned)(this.bits) <= bits) break;
399
state->lens[state->have++] = this.val;
402
if (this.val == 16) {
403
NEEDBITS(this.bits + 2);
405
if (state->have == 0) {
406
strm->msg = (char *)"invalid bit length repeat";
410
len = (unsigned)(state->lens[state->have - 1]);
414
else if (this.val == 17) {
415
NEEDBITS(this.bits + 3);
422
NEEDBITS(this.bits + 7);
428
if (state->have + copy > state->nlen + state->ndist) {
429
strm->msg = (char *)"invalid bit length repeat";
434
state->lens[state->have++] = (unsigned short)len;
438
/* handle error breaks in while */
439
if (state->mode == BAD) break;
441
/* build code tables */
442
state->next = state->codes;
443
state->lencode = (code const FAR *)(state->next);
445
ret = inflate_table(LENS, state->lens, state->nlen, &(state->next),
446
&(state->lenbits), state->work);
448
strm->msg = (char *)"invalid literal/lengths set";
452
state->distcode = (code const FAR *)(state->next);
454
ret = inflate_table(DISTS, state->lens + state->nlen, state->ndist,
455
&(state->next), &(state->distbits), state->work);
457
strm->msg = (char *)"invalid distances set";
461
Tracev((stderr, "inflate: codes ok\n"));
465
/* use inflate_fast() if we have enough input and output */
466
if (have >= 6 && left >= 258) {
468
if (state->whave < state->wsize)
469
state->whave = state->wsize - left;
470
inflate_fast(strm, state->wsize);
475
/* get a literal, length, or end-of-block code */
477
this = state->lencode[BITS(state->lenbits)];
478
if ((unsigned)(this.bits) <= bits) break;
481
if (this.op && (this.op & 0xf0) == 0) {
484
this = state->lencode[last.val +
485
(BITS(last.bits + last.op) >> last.bits)];
486
if ((unsigned)(last.bits + this.bits) <= bits) break;
492
state->length = (unsigned)this.val;
494
/* process literal */
496
Tracevv((stderr, this.val >= 0x20 && this.val < 0x7f ?
497
"inflate: literal '%c'\n" :
498
"inflate: literal 0x%02x\n", this.val));
500
*put++ = (unsigned char)(state->length);
506
/* process end of block */
508
Tracevv((stderr, "inflate: end of block\n"));
515
strm->msg = (char *)"invalid literal/length code";
520
/* length code -- get extra bits, if any */
521
state->extra = (unsigned)(this.op) & 15;
522
if (state->extra != 0) {
523
NEEDBITS(state->extra);
524
state->length += BITS(state->extra);
525
DROPBITS(state->extra);
527
Tracevv((stderr, "inflate: length %u\n", state->length));
529
/* get distance code */
531
this = state->distcode[BITS(state->distbits)];
532
if ((unsigned)(this.bits) <= bits) break;
535
if ((this.op & 0xf0) == 0) {
538
this = state->distcode[last.val +
539
(BITS(last.bits + last.op) >> last.bits)];
540
if ((unsigned)(last.bits + this.bits) <= bits) break;
547
strm->msg = (char *)"invalid distance code";
551
state->offset = (unsigned)this.val;
553
/* get distance extra bits, if any */
554
state->extra = (unsigned)(this.op) & 15;
555
if (state->extra != 0) {
556
NEEDBITS(state->extra);
557
state->offset += BITS(state->extra);
558
DROPBITS(state->extra);
560
if (state->offset > state->wsize - (state->whave < state->wsize ?
562
strm->msg = (char *)"invalid distance too far back";
566
Tracevv((stderr, "inflate: distance %u\n", state->offset));
568
/* copy match from window to output */
571
copy = state->wsize - state->offset;
577
from = put - state->offset;
580
if (copy > state->length) copy = state->length;
581
state->length -= copy;
586
} while (state->length != 0);
590
/* inflate stream terminated properly -- write leftover output */
592
if (left < state->wsize) {
593
if (out(out_desc, state->window, state->wsize - left))
602
default: /* can't happen, but makes compilers happy */
603
ret = Z_STREAM_ERROR;
607
/* Return unused input */
609
strm->next_in = next;
610
strm->avail_in = have;
614
int ZEXPORT inflateBackEnd(strm)
617
if (strm == Z_NULL || strm->state == Z_NULL || strm->zfree == (free_func)0)
618
return Z_STREAM_ERROR;
619
ZFREE(strm, strm->state);
620
strm->state = Z_NULL;
621
Tracev((stderr, "inflate: end\n"));