From: Rob Pike <r@golang.org>
Date: Sat, 28 Jun 2008 19:54:24 +0000 (-0700)
Subject: fix two (!) bugs printing floating point zero
X-Git-Tag: weekly.2009-11-06~3589
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=ff4b01b440221cc399ee4be02b185f47b4f31119;p=gostls13.git

fix two (!) bugs printing floating point zero

SVN=125260
---

diff --git a/src/lib/fmt.go b/src/lib/fmt.go
index c12c39b267..632fb95210 100644
--- a/src/lib/fmt.go
+++ b/src/lib/fmt.go
@@ -347,6 +347,9 @@ func pow10(n int) double {
 }
 
 func unpack(a double) (negative bool, exp int, num double) {
+	if a == 0 {
+		return false, 0, 0.0
+	}
 	neg := a < 0;
 	if neg {
 		a = -a;
@@ -380,9 +383,20 @@ func (f *Fmt) E(a double) *Fmt {
 		prec = f.prec;
 	}
 	prec++;  // one digit left of decimal
+	var s string;
 	// multiply by 10^prec to get decimal places; put decimal after first digit
-	g *= pow10(prec);
-	s := f.integer(int64(g + .5), 10, true, &ldigits);  // get the digits into a string
+	if g == 0 {
+		// doesn't work for zero - fake it
+		s = "000000000000000000000000000000000000000000000000000000000000";
+		if prec < len(s) {
+			s = s[0:prec];
+		} else {
+			prec = len(s);
+		}
+	} else {
+		g *= pow10(prec);
+		s = f.integer(int64(g + .5), 10, true, &ldigits);  // get the digits into a string
+	}
 	s = s[0:1] + "." + s[1:prec];  // insert a decimal point
 	// print exponent with leading 0 if appropriate.
 	es := New().p(2).integer(int64(exp), 10, true, &ldigits);