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-rw-r--r--lib/decompress.c50
1 files changed, 50 insertions, 0 deletions
diff --git a/lib/decompress.c b/lib/decompress.c
new file mode 100644
index 000000000000..edac55cc7823
--- /dev/null
+++ b/lib/decompress.c
@@ -0,0 +1,50 @@
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
16static const struct compress_format {
17 unsigned char magic[2];
18 const char *name;
19 decompress_fn decompressor;
20} compressed_formats[] = {
21#ifdef CONFIG_DECOMPRESS_GZIP
22 { {037, 0213}, "gzip", gunzip },
23 { {037, 0236}, "gzip", gunzip },
24#endif
25#ifdef CONFIG_DECOMPRESS_BZIP2
26 { {0x42, 0x5a}, "bzip2", bunzip2 },
27#endif
28#ifdef CONFIG_DECOMPRESS_LZMA
29 { {0x5d, 0x00}, "lzma", unlzma },
30#endif
31 { {0, 0}, NULL, NULL }
32};
33
34decompress_fn decompress_method(const unsigned char *inbuf, int len,
35 const char **name)
36{
37 const struct compress_format *cf;
38
39 if (len < 2)
40 return NULL; /* Need at least this much... */
41
42 for (cf = compressed_formats; cf->decompressor; cf++) {
43 if (!memcmp(inbuf, cf->magic, 2))
44 break;
45
46 }
47 if (name)
48 *name = cf->name;
49 return cf->decompressor;
50}