freebsd-src/contrib/ntp/libntp/hextolfp.c
1999-12-09 13:01:21 +00:00

68 lines
1.3 KiB
C

/*
* hextolfp - convert an ascii hex string to an l_fp number
*/
#include <stdio.h>
#include <ctype.h>
#include "ntp_fp.h"
#include "ntp_string.h"
#include "ntp_stdlib.h"
int
hextolfp(
const char *str,
l_fp *lfp
)
{
register const char *cp;
register const char *cpstart;
register u_long dec_i;
register u_long dec_f;
char *ind = NULL;
static const char *digits = "0123456789abcdefABCDEF";
dec_i = dec_f = 0;
cp = str;
/*
* We understand numbers of the form:
*
* [spaces]8_hex_digits[.]8_hex_digits[spaces|\n|\0]
*/
while (isspace((int)*cp))
cp++;
cpstart = cp;
while (*cp != '\0' && (cp - cpstart) < 8 &&
(ind = strchr(digits, *cp)) != NULL) {
dec_i = dec_i << 4; /* multiply by 16 */
dec_i += ((ind - digits) > 15) ? (ind - digits) - 6
: (ind - digits);
cp++;
}
if ((cp - cpstart) < 8 || ind == NULL)
return 0;
if (*cp == '.')
cp++;
cpstart = cp;
while (*cp != '\0' && (cp - cpstart) < 8 &&
(ind = strchr(digits, *cp)) != NULL) {
dec_f = dec_f << 4; /* multiply by 16 */
dec_f += ((ind - digits) > 15) ? (ind - digits) - 6
: (ind - digits);
cp++;
}
if ((cp - cpstart) < 8 || ind == NULL)
return 0;
if (*cp != '\0' && !isspace((int)*cp))
return 0;
lfp->l_ui = dec_i;
lfp->l_uf = dec_f;
return 1;
}