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/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-v10.html
*
* Contributors: Details at https://graphviz.org
*************************************************************************/
#include <limits.h>
#include <sfio/sfhdr.h>
#include <stdio.h>
#include <string.h>
/* Convert a floating point value to ASCII
**
** Written by Kiem-Phong Vo
*/
static char *Inf = "Inf", *Zero = "0";
#define SF_INTPART (SF_IDIGITS/2)
#define SF_INFINITE ((_Sfi = 3), Inf)
#define SF_ZERO ((_Sfi = 1), Zero)
/**
* @param dv value to convert
* @param n_digit number of digits wanted
* @param decpt return decimal point
* @param sign return sign
* @param format conversion format
*/
char *_sfcvt(void * dv, int n_digit, int *decpt, int *sign, int format)
{
char *sp;
long n, v;
char *ep, *buf, *endsp;
static char Buf[SF_MAXDIGITS];
*sign = *decpt = 0;
{
double dval = *(double *)dv;
if (dval == 0.)
return SF_ZERO;
else if ((*sign = dval < 0.)) /* assignment = */
dval = -dval;
n = 0;
if (dval >= (double)LONG_MAX) { /* scale to a small enough number to fit an int */
v = SF_MAXEXP10 - 1;
do {
if (dval < _Sfpos10[v])
v -= 1;
else {
dval *= _Sfneg10[v];
if ((n += 1 << v) >= SF_IDIGITS)
return SF_INFINITE;
}
} while (dval >= (double)LONG_MAX);
}
*decpt = (int) n;
buf = sp = Buf + SF_INTPART;
if ((v = (int) dval) != 0) { /* translate the integer part */
dval -= (double) v;
n = snprintf(Buf, sizeof(Buf), "%ld", v);
memmove(Buf + SF_INTPART - n, Buf, n);
if ((*decpt += (int) n) >= SF_IDIGITS)
return SF_INFINITE;
buf = Buf + SF_INTPART - n;
sp = Buf + SF_INTPART;
} else
n = 0;
/* remaining number of digits to compute; add 1 for later rounding */
n = (((format & SFFMT_EFORMAT)
|| *decpt <= 0) ? 1 : *decpt + 1) - n;
if (n_digit > 0)
n += n_digit;
if ((ep = sp + n) > (endsp = Buf + (SF_MAXDIGITS - 2)))
ep = endsp;
if (sp > ep)
sp = ep;
else {
if ((format & SFFMT_EFORMAT) && *decpt == 0 && dval > 0.) {
double d;
while ((int) (d = dval * 10.) == 0) {
dval = d;
*decpt -= 1;
}
}
while (sp < ep) { /* generate fractional digits */
if (dval <= 0.) { /* fill with 0's */
do {
*sp++ = '0';
} while (sp < ep);
goto done;
} else if ((n = (int) (dval *= 10.)) < 10) {
*sp++ = (char) ('0' + n);
dval -= n;
} else { /* n == 10 */
do {
*sp++ = '9';
} while (sp < ep);
}
}
}
}
if (ep <= buf)
ep = buf + 1;
else if (ep < endsp) { /* round the last digit */
*--sp += 5;
while (*sp > '9') {
*sp = '0';
if (sp > buf)
*--sp += 1;
else { /* next power of 10 */
*sp = '1';
*decpt += 1;
if (!(format & SFFMT_EFORMAT)) { /* add one more 0 for %f precision */
ep[-1] = '0';
ep += 1;
}
}
}
}
done:
*--ep = '\0';
_Sfi = ep - buf;
return buf;
}
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