freebsd-src/usr.sbin/xntpd/lib/hextoint.c
1994-09-29 23:04:24 +00:00

39 lines
601 B
C

/*
* hextoint - convert an ascii string in hex to an unsigned
* long, with error checking
*/
#include <ctype.h>
#include "ntp_stdlib.h"
int
hextoint(str, ival)
const char *str;
u_long *ival;
{
register u_long u;
register const char *cp;
cp = str;
if (*cp == '\0')
return 0;
u = 0;
while (*cp != '\0') {
if (!isxdigit(*cp))
return 0;
if (u >= 0x10000000)
return 0; /* overflow */
u <<= 4;
if (*cp <= '9') /* very ascii dependent */
u += *cp++ - '0';
else if (*cp >= 'a')
u += *cp++ - 'a' + 10;
else
u += *cp++ - 'A' + 10;
}
*ival = u;
return 1;
}