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freebsd/contrib/ntp/libntp/hextolfp.c
Xin LI 3311ff84ea MFV r293415:
ntp 4.2.8p5

Reviewed by:	cy, roberto
Relnotes:	yes
Differential Revision:	https://reviews.freebsd.org/D4828
2016-01-08 15:53:48 +00:00

71 lines
1.4 KiB
C

/*
* hextolfp - convert an ascii hex string to an l_fp number
*/
#include <config.h>
#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((unsigned char)*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)
? (u_long)(ind - digits - 6)
: (u_long)(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)
? (u_long)(ind - digits - 6)
: (u_long)(ind - digits);
cp++;
}
if ((cp - cpstart) < 8 || ind == NULL)
return 0;
if (*cp != '\0' && !isspace((unsigned char)*cp))
return 0;
lfp->l_ui = dec_i;
lfp->l_uf = dec_f;
return 1;
}