From 8ebd0d4320a633c520eb94fe4a31e6dc16e4ce42 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Mon, 6 Apr 2009 16:08:23 +0000
Subject: * numeric.c (flo_to_s): reduce fragments if no precision lost.   c.f.
 [ruby-core:23075]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@23144 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 numeric.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

(limited to 'numeric.c')

diff --git a/numeric.c b/numeric.c
index dad085e890..5b051f1452 100644
--- a/numeric.c
+++ b/numeric.c
@@ -522,7 +522,7 @@ static VALUE
 flo_to_s(VALUE flt)
 {
     enum {decimal_mant = DBL_MANT_DIG-DBL_DIG};
-    enum {float_dig = DBL_DIG+2};
+    enum {float_dig = DBL_DIG+1};
     char buf[float_dig + (decimal_mant + CHAR_BIT - 1) / CHAR_BIT + 10];
     double value = RFLOAT_VALUE(flt);
     char *p, *e;
@@ -532,12 +532,15 @@ flo_to_s(VALUE flt)
     else if(isnan(value))
 	return rb_usascii_str_new2("NaN");
 
-    snprintf(buf, sizeof(buf), "%#.*g", float_dig, value); /* ensure to print decimal point */
+# define FLOFMT(buf, size, fmt, prec, val) snprintf(buf, size, fmt, prec, val), \
+    (void)((atof(buf) == val) || snprintf(buf, size, fmt, (prec)+1, val))
+
+    FLOFMT(buf, sizeof(buf), "%#.*g", float_dig, value); /* ensure to print decimal point */
     if (!(e = strchr(buf, 'e'))) {
 	e = buf + strlen(buf);
     }
     if (!ISDIGIT(e[-1])) { /* reformat if ended with decimal point (ex 111111111111111.) */
-	snprintf(buf, sizeof(buf), "%#.*e", float_dig - 1, value);
+	FLOFMT(buf, sizeof(buf), "%#.*e", float_dig - 1, value);
 	if (!(e = strchr(buf, 'e'))) {
 	    e = buf + strlen(buf);
 	}
-- 
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