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>
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@ -375,6 +375,8 @@ static inline char *pack_hex_byte(char *buf, u8 byte)
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return buf;
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}
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extern int hex_to_bin(char ch);
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#ifndef pr_fmt
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#define pr_fmt(fmt) fmt
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#endif
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@ -15,6 +15,24 @@
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const char hex_asc[] = "0123456789abcdef";
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EXPORT_SYMBOL(hex_asc);
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/**
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* hex_to_bin - convert a hex digit to its real value
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* @ch: ascii character represents hex digit
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*
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* hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
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* input.
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*/
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int hex_to_bin(char ch)
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{
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if ((ch >= '0') && (ch <= '9'))
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return ch - '0';
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ch = tolower(ch);
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if ((ch >= 'a') && (ch <= 'f'))
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return ch - 'a' + 10;
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return -1;
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}
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EXPORT_SYMBOL(hex_to_bin);
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/**
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* hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
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* @buf: data blob to dump
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