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 // This should probably be implemented in IL instead of C#, to
  10 // use internalcalls to get its hands on the underlying Type
  11 // of an object.
  12 //
  13
  14 using System.Runtime.CompilerServices;
  15
  16 namespace System {
  17
  18         public class Object {
  19
  20                 // <summary>
  21                 //   Compares this object to the specified object.
  22                 //   Returns true if they are equal, false otherwise.
  23                 // </summary>
  24                 public virtual bool Equals (object o)
  25                 {
  26                         return this == o;
  27                 }
  28
  29                 // <summary>
  30                 //   Compares two objects for equality
  31                 // </summary>
  32                 public static bool Equals (object a, object b)
  33                 {
  34                         if (a == b)
  35                                 return true;
  36
  37                         if (a == null) {
  38                                 if (b == null)
  39                                         return true;
  40                                 return false;
  41                         } else {
  42                                 if (b == null)
  43                                         return false;
  44                                 return a.Equals (b);
  45                         }
  46                 }
  47
  48                 // <summary>
  49                 //   Initializes a new instance of the object class.
  50                 // </summary>
  51                 public Object ()
  52                 {
  53                 }
  54
  55                 // <summary>
  56                 //   Object destructor.
  57                 // </summary>
  58                 ~Object ()
  59                 {
  60                 }
  61
  62                 // <summary>
  63                 //   Returns a hashcode for this object.  Each derived
  64                 //   class should return a hash code that makes sense
  65                 //   for that particular implementation of the object.
  66                 // </summary>
  67                 public virtual int GetHashCode ()
  68                 {
  69                         return 0;
  70                 }
  71
  72                 // <summary>
  73                 //   Returns the Type associated with the object.
  74                 // </summary>
  75                 public Type GetType ()
  76                 {
  77                         return new MonoType (this);
  78                 }
  79
  80                 // <summary>
  81                 //   Shallow copy of the object.
  82                 // </summary>
  83                 [MethodImplAttribute(MethodImplOptions.InternalCall)]
  84                 protected extern object MemberwiseClone ();
  85
  86                 // <summary>
  87                 //   Returns a stringified representation of the object.
  88                 //   This is not supposed to be used for user presentation,
  89                 //   use Format() for that and IFormattable.
  90                 //
  91                 //   ToString is mostly used for debugging purposes.
  92                 // </summary>
  93                 public virtual string ToString ()
  94                 {
  95                         return GetType().FullName;
  96                 }
  97
  98                 // <summary>
  99                 //   Tests whether a is equal to b.
 100                 //   Can not figure out why this even exists
 101                 // </summary>
 102                 public static bool ReferenceEquals (object a, object b)
 103                 {
 104                         return (a == b);
 105                 }
 106         }
 107 }