Merge pull request #819 from brendanzagaeski/patch-1

[mono.git] / mcs / class / corlib / System / Nullable.cs

diff --git a/mcs/class/corlib/System/Nullable.cs b/mcs/class/corlib/System/Nullable.cs
index 89fd585df5cfb330716a17ebb7e137abd8cbbd96..11f6c67dbd4e4d73c69b0a3b4a007025069ea7bd 100644 (file)
--- a/mcs/class/corlib/System/Nullable.cs
+++ b/mcs/class/corlib/System/Nullable.cs
@@ -1,7 +1,8 @@
 //
-// System.Nullable
+// System.Nullable.cs
 //
 // Martin Baulig (martin@ximian.com)
+// Marek Safar  (marek.safar@gmail.com)
 //
 // (C) 2004 Novell, Inc.
 //
@@ -30,46 +31,57 @@
 //
 
 using System.Reflection;
-#if NET_2_0
 using System.Collections.Generic;
-#endif
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using System.Diagnostics;
 
-#if NET_2_0
-namespace System {
+namespace System
+{
+       [ComVisible (true)]
        public static class Nullable {
-               public static int Compare<T> (Nullable<T> left, Nullable<T> right) where T: struct
+
+#if NET_2_1
+               [ComVisible (false)]
+#endif
+               public static int Compare<T> (T? n1, T? n2) where T: struct
                {
-                       IComparable icomparable = left.value as IComparable;
-                       if (icomparable == null)
-                               throw new ArgumentException ("At least one object must implement IComparable.");
-                       if (left.has_value == false && right.has_value == false)
-                               return 0;
-                       if (!left.has_value)
-                               return -1;
-                       if (!right.has_value)
-                               return 1;
+                       if (n1.has_value) {
+                               if (!n2.has_value)
+                                       return 1;
 
-                       return icomparable.CompareTo (right.value);
+                               return Comparer<T>.Default.Compare (n1.value, n2.value);
+                       }
+                       
+                       return n2.has_value ? -1 : 0;
                }
 
-               public static bool Equals<T> (Nullable <T> value1, Nullable<T> value2) where T: struct
+#if NET_2_1
+               [ComVisible (false)]
+#endif
+               public static bool Equals<T> (T? n1, T? n2) where T: struct
                {
-                       return value1.Equals (value2);
+                       if (n1.has_value != n2.has_value)
+                               return false;
+
+                       if (!n1.has_value)
+                               return true;
+
+                       return EqualityComparer<T>.Default.Equals (n1.value, n2.value);
                }
 
                public static Type GetUnderlyingType (Type nullableType)
                {
                        if (nullableType == null)
                                throw new ArgumentNullException ("nullableType");
-                       if (nullableType.IsGenericType && nullableType.GetGenericTypeDefinition () == typeof (Nullable<>))
-                               return nullableType.GetGenericArguments ()[0];
-                       else
-                               return null;
+
+                       return nullableType.IsGenericType && !nullableType.IsGenericTypeDefinition && nullableType.GetGenericTypeDefinition () == typeof(Nullable<>) ?
+                               nullableType.GetGenericArguments () [0] : null;
                }
        }
 
        [Serializable]
+       [DebuggerStepThrough]
        public struct Nullable<T> where T: struct
        {
                #region Sync with runtime code
@@ -108,14 +120,13 @@ namespace System {
 
                bool Equals (Nullable<T> other)
                {
-                       Nullable<T> no = (Nullable<T>) other;
-                       if (no.has_value != has_value)
+                       if (other.has_value != has_value)
                                return false;
 
                        if (has_value == false)
                                return true;
 
-                       return no.value.Equals (value);
+                       return other.value.Equals (value);
                }
 
                public override int GetHashCode ()
@@ -128,15 +139,12 @@ namespace System {
 
                public T GetValueOrDefault ()
                {
-                       return GetValueOrDefault (default (T));
+                       return value;
                }
 
-               public T GetValueOrDefault (T def_value)
+               public T GetValueOrDefault (T defaultValue)
                {
-                       if (!has_value)
-                               return def_value;
-                       else
-                               return value;
+                       return has_value ? value : defaultValue;
                }
 
                public override string ToString ()
@@ -157,14 +165,19 @@ namespace System {
                        return value.Value;
                }
 
+               //
                // These are called by the JIT
-               // Ironicly, the C#  code is the same for these two,
-               // however, on the inside they do somewhat different things
+               //
+#pragma warning disable 169
+               //
+               // JIT implementation of box valuetype System.Nullable`1<T>
+               //
                static object Box (T? o)
                {
-                       if (o == null)
+                       if (!o.has_value)
                                return null;
-                       return (T) o;
+                               
+                       return o.value;
                }
                
                static T? Unbox (object o)
@@ -173,6 +186,6 @@ namespace System {
                                return null;
                        return (T) o;
                }
+#pragma warning restore 169
        }
 }
-#endif