* bignum.c (rb_big_float_cmp): compare an integer and float precisely.

  [ruby-core:31376] [Bug #3589] reported by Tomasz Wegrzanowski.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@36404 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 83 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 411717a77c..c4b8fb1133 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Jul 16 17:57:54 2012  Tanaka Akira  <akr@fsij.org>
+
+	* bignum.c (rb_big_float_cmp): compare an integer and float precisely.
+	  [ruby-core:31376] [Bug #3589] reported by Tomasz Wegrzanowski.
+
 Mon Jul 16 17:29:45 2012  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (rb_big_float_cmp): support fixnum for argument x.
diff --git a/bignum.c b/bignum.c
index 32dace5d6f..18d564ebb5 100644
--- a/bignum.c
+++ b/bignum.c
@@ -1435,6 +1435,8 @@ VALUE
 rb_big_float_cmp(VALUE x, VALUE y)
 {
     double a = RFLOAT_VALUE(y);
+    double yi, yf;
+    VALUE rel;
 
     if (isnan(a))
         return Qnil;
@@ -1442,15 +1444,41 @@ rb_big_float_cmp(VALUE x, VALUE y)
         if (a > 0.0) return INT2FIX(-1);
         else return INT2FIX(1);
     }
+    yf = modf(a, &yi);
     if (FIXNUM_P(x)) {
+#if SIZEOF_LONG * CHAR_BIT < DBL_MANT_DIG /* assume FLT_RADIX == 2 */
         double xd = (double)FIX2LONG(x);
         if (xd < a)
             return INT2FIX(-1);
         if (xd > a)
             return INT2FIX(1);
         return INT2FIX(0);
+#else
+        long xl, yl;
+        if (yi < LONG_MIN)
+            return INT2FIX(1);
+        if (LONG_MAX < yi)
+            return INT2FIX(-1);
+        xl = FIX2LONG(x);
+        yl = (long)yi;
+        if (xl < yl)
+            return INT2FIX(-1);
+        if (xl > yl)
+            return INT2FIX(1);
+        if (yf < 0.0)
+            return INT2FIX(1);
+        if (0.0 < yf)
+            return INT2FIX(-1);
+        return INT2FIX(0);
+#endif
     }
-    return rb_dbl_cmp(rb_big2dbl(x), a);
+    y = rb_dbl2big(yi);
+    rel = rb_big_cmp(x, y);
+    if (yf == 0.0 || rel != INT2FIX(0))
+        return rel;
+    if (yf < 0.0)
+        return INT2FIX(1);
+    return INT2FIX(-1);
 }
 
 /*
diff --git a/test/ruby/test_float.rb b/test/ruby/test_float.rb
index f561d00158..a63c18f8bc 100644
--- a/test/ruby/test_float.rb
+++ b/test/ruby/test_float.rb
@@ -57,6 +57,55 @@ class TestFloat < Test::Unit::TestCase
     assert_equal(a == b, b == a)
   end
 
+  def test_cmp_int
+    100.times {|i|
+      int0 = 1 << i
+      [int0, -int0].each {|int|
+        flt = int.to_f
+        bigger = int + 1
+        smaller = int - 1
+        assert_operator(flt, :==, int)
+        assert_operator(flt, :>, smaller)
+        assert_operator(flt, :>=, smaller)
+        assert_operator(flt, :<, bigger)
+        assert_operator(flt, :<=, bigger)
+        assert_equal(0, flt <=> int)
+        assert_equal(-1, flt <=> bigger)
+        assert_equal(1, flt <=> smaller)
+        assert_operator(int, :==, flt)
+        assert_operator(bigger, :>, flt)
+        assert_operator(bigger, :>=, flt)
+        assert_operator(smaller, :<, flt)
+        assert_operator(smaller, :<=, flt)
+        assert_equal(0, int <=> flt)
+        assert_equal(-1, smaller <=> flt)
+        assert_equal(1, bigger <=> flt)
+        [
+          [int, flt + 0.5, bigger],
+          [smaller, flt - 0.5, int]
+        ].each {|smaller2, flt2, bigger2|
+          next if flt2 == flt2.round
+          assert_operator(flt2, :!=, smaller2)
+          assert_operator(flt2, :!=, bigger2)
+          assert_operator(flt2, :>, smaller2)
+          assert_operator(flt2, :>=, smaller2)
+          assert_operator(flt2, :<, bigger2)
+          assert_operator(flt2, :<=, bigger2)
+          assert_equal(-1, flt2 <=> bigger2)
+          assert_equal(1, flt2 <=> smaller2)
+          assert_operator(smaller2, :!=, flt2)
+          assert_operator(bigger2, :!=, flt2)
+          assert_operator(bigger2, :>, flt2)
+          assert_operator(bigger2, :>=, flt2)
+          assert_operator(smaller2, :<, flt2)
+          assert_operator(smaller2, :<=, flt2)
+          assert_equal(-1, smaller2 <=> flt2)
+          assert_equal(1, bigger2 <=> flt2)
+        }
+      }
+    }
+  end
+
   def test_strtod
     a = Float("0")
     assert(a.abs < Float::EPSILON)