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 void gunzip(void *dst, int dstlen, unsigned char *src, int *lenp);
8
9 static void exit(void)
10 {
11 for (;;);
12 }
13
14 static void *zalloc(unsigned int size)
15 {
16 void *p = avail_ram;
17
18 size = (size + 7) & -8;
19 avail_ram += size;
20 if (avail_ram > end_avail) {
21 //puts("oops... out of memory\n");
22 //pause();
23 exit ();
24 }
25 return p;
26 }
27
28 #define HEAD_CRC 2
29 #define EXTRA_FIELD 4
30 #define ORIG_NAME 8
31 #define COMMENT 0x10
32 #define RESERVED 0xe0
33
34 #define DEFLATED 8
35
36 void gunzip (void *dst, int dstlen, unsigned char *src, int *lenp)
37 {
38 z_stream s;
39 int r, i, flags;
40
41 /* skip header */
42 i = 10;
43 flags = src[3];
44 if (src[2] != DEFLATED || (flags & RESERVED) != 0) {
45 //puts("bad gzipped data\n");
46 exit();
47 }
48 if ((flags & EXTRA_FIELD) != 0)
49 i = 12 + src[10] + (src[11] << 8);
50 if ((flags & ORIG_NAME) != 0)
51 while (src[i++] != 0)
52 ;
53 if ((flags & COMMENT) != 0)
54 while (src[i++] != 0)
55 ;
56 if ((flags & HEAD_CRC) != 0)
57 i += 2;
58 if (i >= *lenp) {
59 //puts("gunzip: ran out of data in header\n");
60 exit();
61 }
62
63 s.workspace = zalloc(zlib_inflate_workspacesize());
64 r = zlib_inflateInit2(&s, -MAX_WBITS);
65 if (r != Z_OK) {
66 //puts("inflateInit2 returned "); puthex(r); puts("\n");
67 exit();
68 }
69 s.next_in = src + i;
70 s.avail_in = *lenp - i;
71 s.next_out = dst;
72 s.avail_out = dstlen;
73 r = zlib_inflate(&s, Z_FINISH);
74 if (r != Z_OK && r != Z_STREAM_END) {
75 //puts("inflate returned "); puthex(r); puts("\n");
76 exit();
77 }
78 *lenp = s.next_out - (unsigned char *) dst;
79 zlib_inflateEnd(&s);
80 }
81
82
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