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authorAndy Shevchenko <ext-andriy.shevchenko@nokia.com>2010-05-24 14:33:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-25 08:07:05 -0700
commit903788892ea0fc7fcaf7e8e5fac9a77379fc215b (patch)
tree6945c6e623bf6fec7cdcd895a881c4d5bf405fa6
parentdb0fd97c270f1e80321f7ae55234643ca0978c54 (diff)
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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>
-rw-r--r--include/linux/kernel.h2
-rw-r--r--lib/hexdump.c18
2 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 05f332afc9e0..8317ec4b9f3b 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -375,6 +375,8 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
return buf;
}
+extern int hex_to_bin(char ch);
+
#ifndef pr_fmt
#define pr_fmt(fmt) fmt
#endif
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