1889c92d2SH. Peter Anvin /* 2889c92d2SH. Peter Anvin * decompress.c 3889c92d2SH. Peter Anvin * 4889c92d2SH. Peter Anvin * Detect the decompression method based on magic number 5889c92d2SH. Peter Anvin */ 6889c92d2SH. Peter Anvin 7889c92d2SH. Peter Anvin #include <linux/decompress/generic.h> 8889c92d2SH. Peter Anvin 9889c92d2SH. Peter Anvin #include <linux/decompress/bunzip2.h> 10889c92d2SH. Peter Anvin #include <linux/decompress/unlzma.h> 11889c92d2SH. Peter Anvin #include <linux/decompress/inflate.h> 12889c92d2SH. Peter Anvin 13889c92d2SH. Peter Anvin #include <linux/types.h> 14889c92d2SH. Peter Anvin #include <linux/string.h> 15889c92d2SH. Peter Anvin 16*23a22d57SH. Peter Anvin #ifndef CONFIG_DECOMPRESS_GZIP 17*23a22d57SH. Peter Anvin # define gunzip NULL 18*23a22d57SH. Peter Anvin #endif 19*23a22d57SH. Peter Anvin #ifndef CONFIG_DECOMPRESS_BZIP2 20*23a22d57SH. Peter Anvin # define bunzip2 NULL 21*23a22d57SH. Peter Anvin #endif 22*23a22d57SH. Peter Anvin #ifndef CONFIG_DECOMPRESS_LZMA 23*23a22d57SH. Peter Anvin # define unlzma NULL 24*23a22d57SH. Peter Anvin #endif 25*23a22d57SH. Peter Anvin 26889c92d2SH. Peter Anvin static const struct compress_format { 27889c92d2SH. Peter Anvin unsigned char magic[2]; 28889c92d2SH. Peter Anvin const char *name; 29889c92d2SH. Peter Anvin decompress_fn decompressor; 30889c92d2SH. Peter Anvin } compressed_formats[] = { 31889c92d2SH. Peter Anvin { {037, 0213}, "gzip", gunzip }, 32889c92d2SH. Peter Anvin { {037, 0236}, "gzip", gunzip }, 33889c92d2SH. Peter Anvin { {0x42, 0x5a}, "bzip2", bunzip2 }, 34889c92d2SH. Peter Anvin { {0x5d, 0x00}, "lzma", unlzma }, 35889c92d2SH. Peter Anvin { {0, 0}, NULL, NULL } 36889c92d2SH. Peter Anvin }; 37889c92d2SH. Peter Anvin 38889c92d2SH. Peter Anvin decompress_fn decompress_method(const unsigned char *inbuf, int len, 39889c92d2SH. Peter Anvin const char **name) 40889c92d2SH. Peter Anvin { 41889c92d2SH. Peter Anvin const struct compress_format *cf; 42889c92d2SH. Peter Anvin 43889c92d2SH. Peter Anvin if (len < 2) 44889c92d2SH. Peter Anvin return NULL; /* Need at least this much... */ 45889c92d2SH. Peter Anvin 46889c92d2SH. Peter Anvin for (cf = compressed_formats; cf->decompressor; cf++) { 47889c92d2SH. Peter Anvin if (!memcmp(inbuf, cf->magic, 2)) 48889c92d2SH. Peter Anvin break; 49889c92d2SH. Peter Anvin 50889c92d2SH. Peter Anvin } 51889c92d2SH. Peter Anvin if (name) 52889c92d2SH. Peter Anvin *name = cf->name; 53889c92d2SH. Peter Anvin return cf->decompressor; 54889c92d2SH. Peter Anvin } 55