mcs/class/corlib/System/Nullable.cs

   1 //
   2 // System.Nullable
   3 //
   4 // Martin Baulig (martin@ximian.com)
   5 //
   6 // (C) 2004 Novell, Inc.
   7 //
   8
   9 //
  10 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System.Reflection;
  33 #if GENERICS
  34 using System.Collections.Generic;
  35 #endif
  36 using System.Runtime.CompilerServices;
  37
  38 #if GENERICS
  39 namespace System
  40 {
  41         [CLSCompliant(false)]
  42         public struct Nullable<T>
  43         {
  44                 T value;
  45                 bool has_value;
  46
  47                 public Nullable (T value)
  48                 {
  49                         this.value = value;
  50                         this.has_value = true;
  51                 }
  52
  53                 public bool HasValue {
  54                         get { return has_value; }
  55                 }
  56
  57                 public T Value {
  58                         get { return value; }
  59                 }
  60
  61                 public T GetValueOrDefault ()
  62                 {
  63                         if (has_value)
  64                                 return value;
  65                         return default (T);
  66                 }
  67
  68                 public T GetValueOrDefault (T def_value)
  69                 {
  70                         if (has_value)
  71                                 return value;
  72                         else
  73                                 return def_value;
  74                 }
  75         }
  76 }
  77 #endif