class/corlib/System/Object.cs

   1 //
   2 // System.Object.cs
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) Ximian, Inc.  http://www.ximian.com
   8 //
   9 //
  10
  11 //
  12 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  13 //
  14 // Permission is hereby granted, free of charge, to any person obtaining
  15 // a copy of this software and associated documentation files (the
  16 // "Software"), to deal in the Software without restriction, including
  17 // without limitation the rights to use, copy, modify, merge, publish,
  18 // distribute, sublicense, and/or sell copies of the Software, and to
  19 // permit persons to whom the Software is furnished to do so, subject to
  20 // the following conditions:
  21 //
  22 // The above copyright notice and this permission notice shall be
  23 // included in all copies or substantial portions of the Software.
  24 //
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  32 //
  33
  34 using System.Runtime.InteropServices;
  35 using System.Runtime.CompilerServices;
  36 using System.Runtime.ConstrainedExecution;
  37
  38 namespace System {
  39
  40         [Serializable]
  41         [ClassInterface (ClassInterfaceType.AutoDual)]
  42         [ComVisible (true)]
  43         public class Object {
  44
  45                 // <summary>
  46                 //   Compares this object to the specified object.
  47                 //   Returns true if they are equal, false otherwise.
  48                 // </summary>
  49                 public virtual bool Equals (object obj)
  50                 {
  51                         return this == obj;
  52                 }
  53
  54                 // <summary>
  55                 //   Compares two objects for equality
  56                 // </summary>
  57                 public static bool Equals (object objA, object objB)
  58                 {
  59                         if (objA == objB)
  60                                 return true;
  61
  62                         if (objA == null || objB == null)
  63                                 return false;
  64
  65                         return objA.Equals (objB);
  66                 }
  67
  68                 // <summary>
  69                 //   Initializes a new instance of the object class.
  70                 // </summary>
  71                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.MayFail)]
  72                 public Object ()
  73                 {
  74                 }
  75
  76                 // <summary>
  77                 //   Object destructor.
  78                 // </summary>
  79                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
  80                 ~Object ()
  81                 {
  82                 }
  83
  84                 // <summary>
  85                 //   Returns a hashcode for this object.  Each derived
  86                 //   class should return a hash code that makes sense
  87                 //   for that particular implementation of the object.
  88                 // </summary>
  89                 public virtual int GetHashCode () {
  90                         return InternalGetHashCode (this);
  91                 }
  92
  93                 // <summary>
  94                 //   Returns the Type associated with the object.
  95                 // </summary>
  96                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  97                 public extern Type GetType ();
  98
  99                 // <summary>
 100                 //   Shallow copy of the object.
 101                 // </summary>
 102                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 103                 protected extern object MemberwiseClone ();
 104
 105                 // <summary>
 106                 //   Returns a stringified representation of the object.
 107                 //   This is not supposed to be used for user presentation,
 108                 //   use Format() for that and IFormattable.
 109                 //
 110                 //   ToString is mostly used for debugging purposes.
 111                 // </summary>
 112                 public virtual string ToString ()
 113                 {
 114                         return GetType ().ToString ();
 115                 }
 116
 117                 // <summary>
 118                 //   Tests whether a is equal to b.
 119                 //   Can not figure out why this even exists
 120                 // </summary>
 121                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 122                 public static bool ReferenceEquals (object objA, object objB)
 123                 {
 124                         return (objA == objB);
 125                 }
 126
 127                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 128                 internal static extern int InternalGetHashCode (object o);
 129
 130                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
 131                 internal extern IntPtr obj_address ();
 132
 133 #pragma warning disable 169
 134                 void FieldGetter (string typeName, string fieldName, ref object val)
 135                 {
 136                         /* never called */
 137                 }
 138
 139                 void FieldSetter (string typeName, string fieldName, object val)
 140                 {
 141                         /* never called */
 142                 }
 143 #pragma warning restore 169
 144         }
 145 }