From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff Woods <kazrak+kernel@cesmail.net>
Subject: Re: Newbie Question -> writing Hexadecimal values
Date: Thu, 25 Sep 2003 15:36:42 -0700
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Cc: Luciano Moreira - igLnx <lucianolnx@ig.com.br>, linux-c-programming@vger.kernel.org

There is at least one bug in your code below:

At 9/25/2003 06:35 PM -0300, Sapuglha wrote:
>#define DecValFromHexaChar(c) ((c)>='A' && (c)<='F' ?'A'-(c)+10 :(c))
>         int hexaVal=0;


I think you mean:
#define DecValFromHexaChar(c) ((c)>='A' && (c)<='F' ?(c)-'A'+10:(c)-'0')
         char hexaVal=0;


Simple function to convert an arbitrary ASCII string from any numeric base 
(up to 36) to an unsigned binary:

int str2int(const char *str, const int base)
{
         int     result = 0;
         char    digit;
         assert(base>1);
         assert(str != NULL);
         while (digit = *str++) {
                 if (digit >= '0' && digit <= '9') digit -= '0';
                 else if (digit >= 'A' && digit <= 'Z') digit -= 'A'-10;
                 else if (digit >= 'a' && digit <= 'z') digit -= 'a'-10;
                 else assert(("invalid digit",0));
                 assert(digit<base);
                 result=result*base+digit;
         }
         return result;
}

int main(void) {        /* sample call */
         printf("%X\n", str2int("DeadBeef", 16));
         return 0;
}

P.S.  That's off the top of my head and there may be logic or other errors, 
but you probably get the gist of the code.

--
Jeff Woods <kazrak+kernel@cesmail.net>