NetBSD/dist/ntp/libntp/dofptoa.c

121 lines
1.8 KiB
C

/* $NetBSD: dofptoa.c,v 1.2 2003/12/04 16:23:36 drochner Exp $ */
/*
* dofptoa - do the grunge work to convert an fp number to ascii
*/
#include <stdio.h>
#include "ntp_fp.h"
#include "lib_strbuf.h"
#include "ntp_string.h"
#include "ntp_stdlib.h"
char *
dofptoa(
u_fp fpv,
int neg,
short ndec,
int msec
)
{
register u_char *cp, *cpend;
register u_long val;
register short dec;
u_char cbuf[12];
u_char *cpdec;
char *buf;
char *bp;
/*
* Get a string buffer before starting
*/
LIB_GETBUF(buf);
/*
* Zero out the buffer
*/
memset((char *)cbuf, 0, sizeof cbuf);
/*
* Set the pointers to point at the first
* decimal place. Get a local copy of the value.
*/
cp = cpend = &cbuf[5];
val = fpv;
/*
* If we have to, decode the integral part
*/
if (!(val & 0xffff0000))
cp--;
else {
register u_short sv = (u_short)(val >> 16);
register u_short tmp;
register u_short ten = 10;
do {
tmp = sv;
sv = (u_short) (sv/ten);
*(--cp) = (u_char)(tmp - ((sv<<3) + (sv<<1)));
} while (sv != 0);
}
/*
* Figure out how much of the fraction to do
*/
if (msec) {
dec = (short)(ndec + 3);
if (dec < 3)
dec = 3;
cpdec = &cbuf[8];
} else {
dec = ndec;
cpdec = cpend;
}
if (dec > 6)
dec = 6;
if (dec > 0) {
do {
val &= 0xffff;
val = (val << 3) + (val << 1);
*cpend++ = (u_char)(val >> 16);
} while (--dec > 0);
}
if (val & 0x8000) {
register u_char *tp;
/*
* Round it. Ick.
*/
tp = cpend;
*(--tp) += 1;
while (*tp >= 10) {
*tp = 0;
*(--tp) += 1;
}
}
/*
* Remove leading zeroes if necessary
*/
while (cp < (cpdec -1) && *cp == 0)
cp++;
/*
* Copy it into the buffer, asciizing as we go.
*/
bp = buf;
if (neg)
*bp++ = '-';
while (cp < cpend) {
if (cp == cpdec)
*bp++ = '.';
*bp++ = (char)(*cp++ + '0');
}
*bp = '\0';
return buf;
}