1 files changed, 123 insertions, 0 deletions
diff --git a/libmath/gfltconv.c b/libmath/gfltconv.c
new file mode 100644
index 00000000..497b71f9
--- /dev/null
+++ b/libmath/gfltconv.c
@@ -0,0 +1,123 @@
+#include "lib9.h"
+#include "mathi.h"
+extern char	*dtoa(double, int, int, int *, int *, char **);
+extern void	freedtoa(char*);
+extern int	_fmtcpy(Fmt*, void*, int, int);
+
+enum
+{
+	NONE	= -1000,
+	FDIGIT	= 20,
+	FDEFLT	= 6,
+	NSIGNIF	= 17
+};
+
+int
+gfltconv(Fmt *f)
+{
+	int flags = f->flags;
+	int precision;
+	int fmt = f->r;
+	double d;
+	int echr, exponent, sign, ndig, nout, i;
+	char *digits, *edigits, ebuf[32], *eptr;
+	char out[64], *pout;
+
+	d = va_arg(f->args, double);
+	echr = 'e';
+	precision = FDEFLT;
+	if(f->flags & FmtPrec)
+		precision = f->prec;
+	if(precision > FDIGIT)
+		precision = FDIGIT;
+	switch(fmt){
+	case 'f':
+		digits = dtoa(d, 3, precision, &exponent, &sign, &edigits);
+		break;
+	case 0x00c9:	/* L'É' */
+	case 'E':
+		echr = 'E';
+		fmt = 'e';
+		/* fall through */
+	case 'e':
+		digits = dtoa(d, 2, 1+precision, &exponent, &sign, &edigits);
+		break;
+	case 'G':
+		echr = 'E';
+		/* fall through */
+	default:
+	case 'g':
+		if((flags&(FmtWidth|FmtPrec)) == 0){
+			g_fmt(out, d, echr);
+			f->flags &= FmtWidth|FmtLeft;
+			return _fmtcpy(f, out, strlen(out), strlen(out));
+		}
+		if (precision > 0)
+			digits = dtoa(d, 2, precision, &exponent, &sign, &edigits);
+		else {
+			digits = dtoa(d, 0, precision, &exponent, &sign, &edigits);
+			precision = edigits - digits;
+			if (exponent > precision && exponent <= precision + 4)
+				precision = exponent;
+			}
+		if(exponent >= -3 && exponent <= precision){
+			fmt = 'f';
+			precision -= exponent;
+		}else{
+			fmt = 'e';
+			--precision;
+		}
+		break;
+	}
+	if (exponent == 9999) {
+		/* Infinity or Nan */
+		precision = 0;
+		exponent = edigits - digits;
+		fmt = 'f';
+	}
+	ndig = edigits-digits;
+	if((f->r=='g' || f->r=='G') && !(flags&FmtSharp)){ /* knock off trailing zeros */
+		if(fmt == 'f'){
+			if(precision+exponent > ndig) {
+				precision = ndig - exponent;
+				if(precision < 0)
+					precision = 0;
+			}
+		}
+		else{
+			if(precision > ndig-1) precision = ndig-1;
+		}
+	}
+	eptr = ebuf;
+	if(fmt != 'f'){					/* exponent */
+		for(i=exponent<=0?1-exponent:exponent-1; i; i/=10)
+			*eptr++ = '0' + i%10;
+		while(eptr<ebuf+2) *eptr++ = '0';
+	}
+	pout = out;
+	if(sign) *pout++ = '-';
+	else if(flags&FmtSign) *pout++ = '+';
+	else if(flags&FmtSpace) *pout++ = ' ';
+	if(fmt == 'f'){
+		for(i=0; i<exponent; i++) *pout++ = i<ndig?digits[i]:'0';
+		if(i == 0) *pout++ = '0';
+		if(precision>0 || flags&FmtSharp) *pout++ = '.';
+		for(i=0; i!=precision; i++)
+			*pout++ = 0<=i+exponent && i+exponent<ndig?digits[i+exponent]:'0';
+	}
+	else{
+		*pout++ = digits[0];
+		if(precision>0 || flags&FmtSharp) *pout++ = '.';
+		for(i=0; i!=precision; i++) *pout++ = i<ndig-1?digits[i+1]:'0';
+	}
+	if(fmt != 'f'){
+		*pout++ = echr;
+		*pout++ = exponent<=0?'-':'+';
+		while(eptr>ebuf) *pout++ = *--eptr;
+	}
+	*pout = 0;
+	freedtoa(digits);
+	f->flags &= FmtWidth|FmtLeft;
+	nout = pout-out;
+	return _fmtcpy(f, out, nout, nout);
+}