tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * decompress.c
3 *
4 * Detect the decompression method based on magic number
5 */
6
7#include <linux/decompress/generic.h>
8
9#include <linux/decompress/bunzip2.h>
10#include <linux/decompress/unlzma.h>
11#include <linux/decompress/inflate.h>
12
13#include <linux/types.h>
14#include <linux/string.h>
15
16#ifndef CONFIG_DECOMPRESS_GZIP
17# define gunzip NULL
18#endif
19#ifndef CONFIG_DECOMPRESS_BZIP2
20# define bunzip2 NULL
21#endif
22#ifndef CONFIG_DECOMPRESS_LZMA
23# define unlzma NULL
24#endif
25
26static const struct compress_format {
27 unsigned char magic[2];
28 const char *name;
29 decompress_fn decompressor;
30} compressed_formats[] = {
31 { {037, 0213}, "gzip", gunzip },
32 { {037, 0236}, "gzip", gunzip },
33 { {0x42, 0x5a}, "bzip2", bunzip2 },
34 { {0x5d, 0x00}, "lzma", unlzma },
35 { {0, 0}, NULL, NULL }
36};
37
38decompress_fn decompress_method(const unsigned char *inbuf, int len,
39 const char **name)
40{
41 const struct compress_format *cf;
42
43 if (len < 2)
44 return NULL; /* Need at least this much... */
45
46 for (cf = compressed_formats; cf->name; cf++) {
47 if (!memcmp(inbuf, cf->magic, 2))
48 break;
49
50 }
51 if (name)
52 *name = cf->name;
53 return cf->decompressor;
54}