From 903788892ea0fc7fcaf7e8e5fac9a77379fc215b Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Date: Mon, 24 May 2010 14:33:23 -0700
Subject: [PATCH] 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>
---
include/linux/kernel.h | 2 ++
lib/hexdump.c | 18 ++++++++++++++++++
2 files changed, 20 insertions(+)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 05f332afc9e01..8317ec4b9f3b4 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 1bd6a97797744..5d7a4802c5623 100644
--- a/lib/hexdump.c
+++ b/lib/hexdump.c
@@ -15,6 +15,24 @@
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
--
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