1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/zlib.h>
3
4 /* bits taken from ppc */
5
6 extern void *avail_ram, *end_avail;
7
exit(void)8 void exit (void)
9 {
10 for (;;);
11 }
12
zalloc(unsigned size)13 void *zalloc(unsigned size)
14 {
15 void *p = avail_ram;
16
17 size = (size + 7) & -8;
18 avail_ram += size;
19 if (avail_ram > end_avail) {
20 //puts("oops... out of memory\n");
21 //pause();
22 exit ();
23 }
24 return p;
25 }
26
27 #define HEAD_CRC 2
28 #define EXTRA_FIELD 4
29 #define ORIG_NAME 8
30 #define COMMENT 0x10
31 #define RESERVED 0xe0
32
33 #define DEFLATED 8
34
gunzip(void * dst,int dstlen,unsigned char * src,int * lenp)35 void gunzip (void *dst, int dstlen, unsigned char *src, int *lenp)
36 {
37 z_stream s;
38 int r, i, flags;
39
40 /* skip header */
41 i = 10;
42 flags = src[3];
43 if (src[2] != DEFLATED || (flags & RESERVED) != 0) {
44 //puts("bad gzipped data\n");
45 exit();
46 }
47 if ((flags & EXTRA_FIELD) != 0)
48 i = 12 + src[10] + (src[11] << 8);
49 if ((flags & ORIG_NAME) != 0)
50 while (src[i++] != 0)
51 ;
52 if ((flags & COMMENT) != 0)
53 while (src[i++] != 0)
54 ;
55 if ((flags & HEAD_CRC) != 0)
56 i += 2;
57 if (i >= *lenp) {
58 //puts("gunzip: ran out of data in header\n");
59 exit();
60 }
61
62 s.workspace = zalloc(zlib_inflate_workspacesize());
63 r = zlib_inflateInit2(&s, -MAX_WBITS);
64 if (r != Z_OK) {
65 //puts("inflateInit2 returned "); puthex(r); puts("\n");
66 exit();
67 }
68 s.next_in = src + i;
69 s.avail_in = *lenp - i;
70 s.next_out = dst;
71 s.avail_out = dstlen;
72 r = zlib_inflate(&s, Z_FINISH);
73 if (r != Z_OK && r != Z_STREAM_END) {
74 //puts("inflate returned "); puthex(r); puts("\n");
75 exit();
76 }
77 *lenp = s.next_out - (unsigned char *) dst;
78 zlib_inflateEnd(&s);
79 }
80
81