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fnum.c
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/*
* _fnum() - converts floating numbers to ascii decimal
* representations.
*/
#define uchar unsigned char
#define putc(c) (*pputc)(c)
#define buf (xbuf+2)
extern double _frndint();
extern int strlen(char *);
extern int abs(int);
_fnum(val, prec, width, efmt, pputc)
double val;
char width, prec, efmt;
void (* pputc)();
{
register char * cp, * xp;
int exp;
char digs;
short twid;
uchar sign;
char xbuf[60];
if(prec < 0)
prec = 6;
twid = 0;
if(val < 0.0) {
val = -val;
sign = 1;
} else
sign = 0;
exp = 0;
/*
if(efmt == 0 && prec == 0)
val = _frndint(val); /* round to integer */
_fbcd(val, &exp, buf);
cp = buf;
while(*cp == '0')
cp++;
if(*cp == 0) /* all zero */
cp--;
if(strlen(cp) > 1) {
xp = cp+strlen(cp)-1;
while(*xp == '0') { /* remove traiing zeros */
*xp-- = 0;
exp++;
}
} else if(*cp == '0')
exp = 0;
cp[-1] = '0';
digs = strlen(cp); /* number of significant digits */
if(efmt == 0 && prec == 0 || efmt == 1 && exp >= 0 && exp <= 5+prec) {
/* use d format */
if(exp < 0) { /* too much precision */
char c;
xp = cp+digs+exp;
c = *xp;
*xp = 0;
if(c >= '5')
for(;;)
if((*--xp += 1) == '9'+1)
*xp = '0';
else
break;
if(xp < cp)
cp = xp;
digs = strlen(cp);
exp = 0;
}
width -= (twid = digs + exp + sign);
while(width > 0) {
putc(' ');
width--;
twid++;
}
if(sign)
putc('-');
while(*cp)
putc(*cp++);
while(exp > 0) {
putc('0');
exp--;
}
return twid;
}
if(efmt == 1 && exp >= 5 || exp + digs < -4)
efmt++;
if(efmt >= 2) { /* use e format */
width -= (twid = sign + prec + 6);
if(digs > prec+1) { /* need to round it */
char c;
loop:
xp = cp+prec+1;
exp += digs-(prec+1);
c = *xp;
*xp = 0;
if(c >= '5')
for(;;)
if((*--xp += 1) == '9'+1)
*xp = '0';
else
break;
if(xp < cp)
cp = xp;
digs = strlen(cp);
if(digs > prec+1)
goto loop;
}
exp += digs - 1; /* allow for moving dec. pt. */
if(abs(exp) >= 100) /* 3 digit exponent */
width--;
prec -= digs - 1;
while(width > 0) {
putc(' ');
width--;
twid++;
}
if(sign)
putc('-');
putc(*cp++);
putc('.');
while(*cp)
putc(*cp++);
while(prec > 0) {
putc('0');
prec--;
}
putc('e');
if(exp < 0) {
exp = -exp;
putc('-');
} else
putc('+');
if(exp >= 100) {
putc(exp / 100 + '0');
exp %= 100;
}
putc(exp / 10 + '0');
putc(exp % 10 + '0');
return twid;
}
/* here for f format */
if(exp + prec < 0) { /* too much precision */
char c;
xp = cp+digs+exp+prec;
c = *xp;
*xp = 0;
if(c >= '5')
for(;;)
if((*--xp += 1) == '9'+1)
*xp = '0';
else
break;
if(xp < cp)
cp = xp;
digs = strlen(cp);
exp = -prec;
}
prec += exp;
twid = 1 + prec + sign + digs;
digs = -digs;
if(exp <= digs)
twid += digs - exp + 1;
width -= twid;
while(width > 0) {
putc(' ');
width--;
}
if(sign)
putc('-');
if(exp <= digs) {
putc('0');
putc('.');
while(exp < digs) {
putc('0');
exp++;
}
}
while(*cp) {
putc(*cp++);
if(++digs == exp)
putc('.');
}
while(exp > 0) {
putc('0');
prec--;
if(--exp == 0)
putc('.');
}
while(prec > 0) {
putc('0');
prec--;
}
return twid;
}