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authorLen Brown <len.brown@intel.com>2009-04-05 02:14:15 -0400
committerLen Brown <len.brown@intel.com>2009-04-05 02:14:15 -0400
commit478c6a43fcbc6c11609f8cee7c7b57223907754f (patch)
treea7f7952099da60d33032aed6de9c0c56c9f8779e /lib/decompress.c
parent8a3f257c704e02aee9869decd069a806b45be3f1 (diff)
parent6bb597507f9839b13498781e481f5458aea33620 (diff)
Merge branch 'linus' into release
Conflicts: arch/x86/kernel/cpu/cpufreq/longhaul.c Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'lib/decompress.c')
-rw-r--r--lib/decompress.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/lib/decompress.c b/lib/decompress.c
new file mode 100644
index 00000000000..d2842f57167
--- /dev/null
+++ b/lib/decompress.c
@@ -0,0 +1,54 @@
+/*
+ * decompress.c
+ *
+ * Detect the decompression method based on magic number
+ */
+
+#include <linux/decompress/generic.h>
+
+#include <linux/decompress/bunzip2.h>
+#include <linux/decompress/unlzma.h>
+#include <linux/decompress/inflate.h>
+
+#include <linux/types.h>
+#include <linux/string.h>
+
+#ifndef CONFIG_DECOMPRESS_GZIP
+# define gunzip NULL
+#endif
+#ifndef CONFIG_DECOMPRESS_BZIP2
+# define bunzip2 NULL
+#endif
+#ifndef CONFIG_DECOMPRESS_LZMA
+# define unlzma NULL
+#endif
+
+static const struct compress_format {
+ unsigned char magic[2];
+ const char *name;
+ decompress_fn decompressor;
+} compressed_formats[] = {
+ { {037, 0213}, "gzip", gunzip },
+ { {037, 0236}, "gzip", gunzip },
+ { {0x42, 0x5a}, "bzip2", bunzip2 },
+ { {0x5d, 0x00}, "lzma", unlzma },
+ { {0, 0}, NULL, NULL }
+};
+
+decompress_fn decompress_method(const unsigned char *inbuf, int len,
+ const char **name)
+{
+ const struct compress_format *cf;
+
+ if (len < 2)
+ return NULL; /* Need at least this much... */
+
+ for (cf = compressed_formats; cf->name; cf++) {
+ if (!memcmp(inbuf, cf->magic, 2))
+ break;
+
+ }
+ if (name)
+ *name = cf->name;
+ return cf->decompressor;
+}