view loadtools/hexdecode.c @ 7:aa1f6fe16fef

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author Michael Spacefalcon <msokolov@ivan.Harhan.ORG>
date Tue, 30 Apr 2013 07:19:48 +0000
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/*
 * This module contains the decode_hex_byte() function,
 * which is used by the SREC file reader and will likely be used
 * by other code as well, such as the dump-to-file function
 * of loadtool.
 */

#include <ctype.h>

decode_hex_byte(s)
	char *s;
{
	register int u, l;

	if (!isxdigit(s[0]) || !isxdigit(s[1]))
		return(-1);
	if (isdigit(s[0]))
		u = s[0] - '0';
	else if (isupper(s[0]))
		u = s[0] - 'A' + 10;
	else
		u = s[0] - 'a' + 10;
	if (isdigit(s[1]))
		l = s[1] - '0';
	else if (isupper(s[1]))
		l = s[1] - 'A' + 10;
	else
		l = s[1] - 'a' + 10;
	return((u << 4) | l);
}