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| author | Andy Shevchenko <ext-andriy.shevchenko@nokia.com> | 2010-05-24 23:33:23 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-25 17:07:05 +0200 |
| commit | 903788892ea0fc7fcaf7e8e5fac9a77379fc215b (patch) | |
| tree | 6945c6e623bf6fec7cdcd895a881c4d5bf405fa6 /lib/hexdump.c | |
| parent | lib/hexdump.c: reduce stack variable size and cleanups (diff) | |
| download | linux-903788892ea0fc7fcaf7e8e5fac9a77379fc215b.tar.xz linux-903788892ea0fc7fcaf7e8e5fac9a77379fc215b.zip | |
lib: introduce common method to convert hex digits
hex_to_bin() is a little method which converts hex digit to its actual
value. There are plenty of places where such functionality is needed.
[akpm@linux-foundation.org: use tolower(), saving 3 bytes, test the more common case first - it's quicker]
[akpm@linux-foundation.org: relocate tolower to make it even faster! (Joe)]
Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Cc: Tilman Schmidt <tilman@imap.cc>
Cc: Duncan Sands <duncan.sands@free.fr>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: "Richard Russon (FlatCap)" <ldm@flatcap.org>
Cc: John W. Linville <linville@tuxdriver.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/hexdump.c')
| -rw-r--r-- | lib/hexdump.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/lib/hexdump.c b/lib/hexdump.c index 1bd6a9779774..5d7a4802c562 100644 --- a/lib/hexdump.c +++ b/lib/hexdump.c @@ -16,6 +16,24 @@ const char hex_asc[] = "0123456789abcdef"; EXPORT_SYMBOL(hex_asc); /** + * hex_to_bin - convert a hex digit to its real value + * @ch: ascii character represents hex digit + * + * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad + * input. + */ +int hex_to_bin(char ch) +{ + if ((ch >= '0') && (ch <= '9')) + return ch - '0'; + ch = tolower(ch); + if ((ch >= 'a') && (ch <= 'f')) + return ch - 'a' + 10; + return -1; +} +EXPORT_SYMBOL(hex_to_bin); + +/** * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory * @buf: data blob to dump * @len: number of bytes in the @buf |