1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun #include <linux/zlib.h>
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun /* bits taken from ppc */
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun extern void *avail_ram, *end_avail;
7*4882a593Smuzhiyun
exit(void)8*4882a593Smuzhiyun void exit (void)
9*4882a593Smuzhiyun {
10*4882a593Smuzhiyun for (;;);
11*4882a593Smuzhiyun }
12*4882a593Smuzhiyun
zalloc(unsigned size)13*4882a593Smuzhiyun void *zalloc(unsigned size)
14*4882a593Smuzhiyun {
15*4882a593Smuzhiyun void *p = avail_ram;
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun size = (size + 7) & -8;
18*4882a593Smuzhiyun avail_ram += size;
19*4882a593Smuzhiyun if (avail_ram > end_avail) {
20*4882a593Smuzhiyun //puts("oops... out of memory\n");
21*4882a593Smuzhiyun //pause();
22*4882a593Smuzhiyun exit ();
23*4882a593Smuzhiyun }
24*4882a593Smuzhiyun return p;
25*4882a593Smuzhiyun }
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun #define HEAD_CRC 2
28*4882a593Smuzhiyun #define EXTRA_FIELD 4
29*4882a593Smuzhiyun #define ORIG_NAME 8
30*4882a593Smuzhiyun #define COMMENT 0x10
31*4882a593Smuzhiyun #define RESERVED 0xe0
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun #define DEFLATED 8
34*4882a593Smuzhiyun
gunzip(void * dst,int dstlen,unsigned char * src,int * lenp)35*4882a593Smuzhiyun void gunzip (void *dst, int dstlen, unsigned char *src, int *lenp)
36*4882a593Smuzhiyun {
37*4882a593Smuzhiyun z_stream s;
38*4882a593Smuzhiyun int r, i, flags;
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun /* skip header */
41*4882a593Smuzhiyun i = 10;
42*4882a593Smuzhiyun flags = src[3];
43*4882a593Smuzhiyun if (src[2] != DEFLATED || (flags & RESERVED) != 0) {
44*4882a593Smuzhiyun //puts("bad gzipped data\n");
45*4882a593Smuzhiyun exit();
46*4882a593Smuzhiyun }
47*4882a593Smuzhiyun if ((flags & EXTRA_FIELD) != 0)
48*4882a593Smuzhiyun i = 12 + src[10] + (src[11] << 8);
49*4882a593Smuzhiyun if ((flags & ORIG_NAME) != 0)
50*4882a593Smuzhiyun while (src[i++] != 0)
51*4882a593Smuzhiyun ;
52*4882a593Smuzhiyun if ((flags & COMMENT) != 0)
53*4882a593Smuzhiyun while (src[i++] != 0)
54*4882a593Smuzhiyun ;
55*4882a593Smuzhiyun if ((flags & HEAD_CRC) != 0)
56*4882a593Smuzhiyun i += 2;
57*4882a593Smuzhiyun if (i >= *lenp) {
58*4882a593Smuzhiyun //puts("gunzip: ran out of data in header\n");
59*4882a593Smuzhiyun exit();
60*4882a593Smuzhiyun }
61*4882a593Smuzhiyun
62*4882a593Smuzhiyun s.workspace = zalloc(zlib_inflate_workspacesize());
63*4882a593Smuzhiyun r = zlib_inflateInit2(&s, -MAX_WBITS);
64*4882a593Smuzhiyun if (r != Z_OK) {
65*4882a593Smuzhiyun //puts("inflateInit2 returned "); puthex(r); puts("\n");
66*4882a593Smuzhiyun exit();
67*4882a593Smuzhiyun }
68*4882a593Smuzhiyun s.next_in = src + i;
69*4882a593Smuzhiyun s.avail_in = *lenp - i;
70*4882a593Smuzhiyun s.next_out = dst;
71*4882a593Smuzhiyun s.avail_out = dstlen;
72*4882a593Smuzhiyun r = zlib_inflate(&s, Z_FINISH);
73*4882a593Smuzhiyun if (r != Z_OK && r != Z_STREAM_END) {
74*4882a593Smuzhiyun //puts("inflate returned "); puthex(r); puts("\n");
75*4882a593Smuzhiyun exit();
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun *lenp = s.next_out - (unsigned char *) dst;
78*4882a593Smuzhiyun zlib_inflateEnd(&s);
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun
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