mirror of
https://github.com/freebsd/freebsd-src
synced 2024-10-03 07:04:53 +00:00
72 lines
1.5 KiB
C
72 lines
1.5 KiB
C
/*
|
|
* mstolfp - convert an ascii string in milliseconds to an l_fp number
|
|
*/
|
|
#include <config.h>
|
|
#include <stdio.h>
|
|
#include <ctype.h>
|
|
|
|
#include "ntp_fp.h"
|
|
#include "ntp_stdlib.h"
|
|
|
|
int
|
|
mstolfp(
|
|
const char *str,
|
|
l_fp *lfp
|
|
)
|
|
{
|
|
int ch, neg = 0;
|
|
u_int32 q, r;
|
|
|
|
/*
|
|
* We understand numbers of the form:
|
|
*
|
|
* [spaces][-|+][digits][.][digits][spaces|\n|\0]
|
|
*
|
|
* This is kinda hack. We use 'atolfp' to do the basic parsing
|
|
* (after some initial checks) and then divide the result by
|
|
* 1000. The original implementation avoided that by
|
|
* hacking up the input string to move the decimal point, but
|
|
* that needed string manipulations prone to buffer overruns.
|
|
* To avoid that trouble we do the conversion first and adjust
|
|
* the result.
|
|
*/
|
|
|
|
while (isspace(ch = *(const unsigned char*)str))
|
|
++str;
|
|
|
|
switch (ch) {
|
|
case '-': neg = TRUE;
|
|
case '+': ++str;
|
|
default : break;
|
|
}
|
|
|
|
if (!isdigit(ch = *(const unsigned char*)str) && (ch != '.'))
|
|
return 0;
|
|
if (!atolfp(str, lfp))
|
|
return 0;
|
|
|
|
/* now do a chained/overlapping division by 1000 to get from
|
|
* seconds to msec. 1000 is small enough to go with temporary
|
|
* 32bit accus for Q and R.
|
|
*/
|
|
q = lfp->l_ui / 1000u;
|
|
r = lfp->l_ui - (q * 1000u);
|
|
lfp->l_ui = q;
|
|
|
|
r = (r << 16) | (lfp->l_uf >> 16);
|
|
q = r / 1000u;
|
|
r = ((r - q * 1000) << 16) | (lfp->l_uf & 0x0FFFFu);
|
|
lfp->l_uf = q << 16;
|
|
q = r / 1000;
|
|
lfp->l_uf |= q;
|
|
r -= q * 1000u;
|
|
|
|
/* fix sign */
|
|
if (neg)
|
|
L_NEG(lfp);
|
|
/* round */
|
|
if (r >= 500)
|
|
L_ADDF(lfp, (neg ? -1 : 1));
|
|
return 1;
|
|
}
|