2007-11-14 Zoltan Varga <vargaz@gmail.com>

[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 b114ee5abcd9633fca620c3781d84d7f86f2a579..b981afb00596bb21fb9788cce4c8513c2a355adc 100644 (file)
--- a/mcs/class/corlib/System/Nullable.cs
+++ b/mcs/class/corlib/System/Nullable.cs
@@ -34,11 +34,15 @@ using System.Reflection;
 using System.Collections.Generic;
 #endif
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 
 #if NET_2_0
 namespace System {
+#if NET_2_0
+       [ComVisible (true)]
+#endif
        public static class Nullable {
-               public static int Compare<T> (Nullable<T> left, Nullable<T> right)
+               public static int Compare<T> (Nullable<T> left, Nullable<T> right) where T: struct
                {
                        IComparable icomparable = left.value as IComparable;
                        if (icomparable == null)
@@ -53,58 +57,33 @@ namespace System {
                        return icomparable.CompareTo (right.value);
                }
 
-               public static bool Equals<T> (Nullable <T> value1, Nullable<T> value2)
+               public static bool Equals<T> (Nullable <T> value1, Nullable<T> value2) where T: struct
                {
                        return value1.Equals (value2);
                }
 
-               public static Nullable<T> FromObject<T> (object value)
-               {
-                       if (!(value is T))
-                               throw new ArgumentException ("Object type can not be converted to target type.");
-
-                       return new Nullable<T> ((T) value);
-               }
-
-               public static T GetValueOrDefault<T>(Nullable<T> value)
-               {
-                       return GetValueOrDefault<T> (value, default (T));
-               }
-
-               public static T GetValueOrDefault<T> (Nullable<T> value, T defaultValue)
-               {
-                       if (!value.has_value)
-                               return defaultValue;
-
-                       return value.value;
-               }
-
-               public static bool HasValue<T> (Nullable <T> value)
-               {
-                       return value.has_value;
-               }
-
-               public static object ToObject<T> (Nullable<T> value)
+               public static Type GetUnderlyingType (Type nullableType)
                {
-                       if (!value.has_value)
+                       if (nullableType == null)
+                               throw new ArgumentNullException ("nullableType");
+                       if (nullableType.IsGenericType && nullableType.GetGenericTypeDefinition () == typeof (Nullable<>))
+                               return nullableType.GetGenericArguments ()[0];
+                       else
                                return null;
-
-                       return (object)value.value;
                }
        }
-       
-       public struct Nullable<T> : IComparable, INullableValue
+
+       [Serializable]
+       public struct Nullable<T> where T: struct
        {
+               #region Sync with runtime code
                internal T value;
                internal bool has_value;
+               #endregion
 
                public Nullable (T value)
                {
-                       if (value == null)
-                               this.has_value = false;
-                       else
-                               this.has_value = true;
-                       
+                       this.has_value = true;
                        this.value = value;
                }
 
@@ -121,50 +100,26 @@ namespace System {
                        }
                }
 
-               object INullableValue.Value {
-                       get {
-                               return (object)Value;
-                       }
-               }
-               
-               [Obsolete]
-               public int CompareTo (Nullable<T> other)
-               {
-                       return Nullable.Compare<T> (this, other);
-               }
-
-               [Obsolete]
-               public int CompareTo (object other)
-               {
-                       if (!(other is Nullable<T>))
-                               throw new ArgumentException ("Object type can not be converted to target type.");
-
-                       return Nullable.Compare<T> (this, (Nullable<T>) other);
-               }
-
                public override bool Equals (object other)
                {
+                       if (other == null)
+                               return has_value == false;
                        if (!(other is Nullable<T>))
                                return false;
 
                        return Equals ((Nullable <T>) other);
                }
 
-               public bool Equals (Nullable<T> other)
+               bool Equals (Nullable<T> other)
                {
-                       if (other.has_value != has_value)
+                       Nullable<T> no = (Nullable<T>) other;
+                       if (no.has_value != has_value)
                                return false;
 
                        if (has_value == false)
                                return true;
 
-                       return other.value.Equals (value);
-               }
-
-               [Obsolete]
-               public static Nullable<T> FromObject (object value)
-               {
-                       return Nullable.FromObject<T> (value);
+                       return no.value.Equals (value);
                }
 
                public override int GetHashCode ()
@@ -175,24 +130,17 @@ namespace System {
                        return value.GetHashCode ();
                }
 
-               [Obsolete]
                public T GetValueOrDefault ()
                {
-                       return Nullable.GetValueOrDefault<T> (this, default (T));
+                       return GetValueOrDefault (default (T));
                }
 
-               [Obsolete]
                public T GetValueOrDefault (T def_value)
-               {
-                       return Nullable.GetValueOrDefault<T> (this, def_value);
-               }
-
-               public object ToObject ()
                {
                        if (!has_value)
-                               return null;
-
-                       return (object)value;
+                               return def_value;
+                       else
+                               return value;
                }
 
                public override string ToString ()
@@ -200,7 +148,7 @@ namespace System {
                        if (has_value)
                                return value.ToString ();
                        else
-                               return "";
+                               return String.Empty;
                }
 
                public static implicit operator Nullable<T> (T value)
@@ -213,14 +161,21 @@ namespace System {
                        return value.Value;
                }
 
-               public static bool operator == (Nullable<T> left, Nullable<T> right)
+               // 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
+               static object Box (T? o)
                {
-                       return left.Equals (right);
+                       if (o == null)
+                               return null;
+                       return (T) o;
                }
-
-               public static bool operator != (Nullable<T> left, Nullable<T> right)
+               
+               static T? Unbox (object o)
                {
-                       return !left.Equals (right);
+                       if (o == null)
+                               return null;
+                       return (T) o;
                }
        }
 }