Merge pull request #2216 from akoeplinger/fix-array-sort
[mono.git] / mcs / 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 #pragma warning disable 169
131                 void FieldGetter (string typeName, string fieldName, ref object val)
132                 {
133                         /* never called */
134                 }
135
136                 void FieldSetter (string typeName, string fieldName, object val)
137                 {
138                         /* never called */
139                 }
140 #pragma warning restore 169
141         }
142 }