From bb45f1b2b8a21a8e6de705c9a68724a49563c66c Mon Sep 17 00:00:00 2001
From: tadf <tadf@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Sun, 19 Jul 2009 13:25:05 +0000
Subject: 	* rational.c (float_to_r): an improvement.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@24206 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 rational.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

(limited to 'rational.c')

diff --git a/rational.c b/rational.c
index c14bc94681..e5ae7301fc 100644
--- a/rational.c
+++ b/rational.c
@@ -1695,6 +1695,9 @@ float_decode(VALUE self)
 }
 #endif
 
+#define id_lshift rb_intern("<<")
+#define f_lshift(x,n) rb_funcall(x, id_lshift, 1, n)
+
 /*
  * call-seq:
  *    flt.to_r  ->  rational
@@ -1717,7 +1720,20 @@ float_to_r(VALUE self)
     VALUE f, n;
 
     float_decode_internal(self, &f, &n);
+#if FLT_RADIX == 2
+    {
+	long ln = FIX2LONG(n);
+
+	if (ln == 0)
+	    return f_to_r(f);
+	if (ln > 0)
+	    return f_to_r(f_lshift(f, n));
+	ln = -ln;
+	return rb_rational_new2(f, f_lshift(ONE, INT2FIX(ln)));
+    }
+#else
     return f_to_r(f_mul(f, f_expt(INT2FIX(FLT_RADIX), n)));
+#endif
 }
 
 static VALUE rat_pat, an_e_pat, a_dot_pat, underscores_pat, an_underscore;
-- 
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