* ext/bigdecimal/bigdecimal.c (Init_bigdecimal): add two new constants BigDecimal::INFINITY and BigDecimal::NAN.

* ext/bigdecimal/lib/bigdecimal/math.rb (BigMath.exp): modify the behaviors for infinity arguments as same as Math.exp.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@28533 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 17 insertions, 1 deletions

diff --git a/ext/bigdecimal/bigdecimal.c b/ext/bigdecimal/bigdecimal.c
index 817fc13cfd..340ea8bb80 100644
--- a/ext/bigdecimal/bigdecimal.c
+++ b/ext/bigdecimal/bigdecimal.c
@@ -1902,6 +1902,8 @@ BigDecimal_sign(VALUE self)
 void
 Init_bigdecimal(void)
 {
+    VALUE arg;
+
     /* Initialize VP routines */
     VpInit((U_LONG)0);
 
@@ -2023,6 +2025,12 @@ Init_bigdecimal(void)
     /* -3: Indicates that a value is negative and infinite. See BigDecimal.sign. */
     rb_define_const(rb_cBigDecimal, "SIGN_NEGATIVE_INFINITE",INT2FIX(VP_SIGN_NEGATIVE_INFINITE));
 
+    arg = rb_str_new2("+Infinity");
+    rb_define_const(rb_cBigDecimal, "INFINITY", BigDecimal_global_new(1, &arg, rb_cBigDecimal));
+    arg = rb_str_new2("NaN");
+    rb_define_const(rb_cBigDecimal, "NAN", BigDecimal_global_new(1, &arg, rb_cBigDecimal));
+
+
     /* instance methods */
     rb_define_method(rb_cBigDecimal, "precs", BigDecimal_prec, 0);
 
diff --git a/ext/bigdecimal/lib/bigdecimal/math.rb b/ext/bigdecimal/lib/bigdecimal/math.rb
index 41fc69f66c..c17841fdb9 100644
--- a/ext/bigdecimal/lib/bigdecimal/math.rb
+++ b/ext/bigdecimal/lib/bigdecimal/math.rb
@@ -155,7 +155,15 @@ module BigMath
   # -> "0.271828182845904523536028752390026306410273E1"
   def exp(x, prec)
     raise ArgumentError, "Zero or negative precision for exp" if prec <= 0
-    return BigDecimal("NaN") if x.infinite? || x.nan?
+    if x.infinite?
+      if x < 0
+        return BigDecimal("0", prec)
+      else
+        return BigDecimal("+Infinity", prec)
+      end
+    elsif x.nan?
+      return BigDecimal("NaN", prec)
+    end
     n    = prec + BigDecimal.double_fig
     one  = BigDecimal("1")
     x = -x if neg = x < 0