NetBSD/dist/ntp/libntp/hextoint.c

42 lines
684 B
C

/* $NetBSD: hextoint.c,v 1.2 2003/12/04 16:23:36 drochner Exp $ */
/*
* hextoint - convert an ascii string in hex to an unsigned
* long, with error checking
*/
#include <ctype.h>
#include "ntp_stdlib.h"
int
hextoint(
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((int)*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;
}