class/corlib/System/IntPtr.cs

   1 //
   2 // System.IntPtr.cs
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // Maintainer:
   8 //       Michael Lambert, michaellambert@email.com
   9 //
  10 // (C) Ximian, Inc.  http://www.ximian.com
  11 //
  12 // Remarks:
  13 //   Requires '/unsafe' compiler option.  This class uses void*,
  14 //   in overloaded constructors, conversion, and cast members in
  15 //   the public interface.  Using pointers is not valid CLS and
  16 //   the methods in question have been marked with  the
  17 //   CLSCompliant attribute that avoid compiler warnings.
  18 //
  19 // FIXME: How do you specify a native int in C#?  I am going to have to do some figuring out
  20 //
  21
  22 //
  23 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  24 //
  25 // Permission is hereby granted, free of charge, to any person obtaining
  26 // a copy of this software and associated documentation files (the
  27 // "Software"), to deal in the Software without restriction, including
  28 // without limitation the rights to use, copy, modify, merge, publish,
  29 // distribute, sublicense, and/or sell copies of the Software, and to
  30 // permit persons to whom the Software is furnished to do so, subject to
  31 // the following conditions:
  32 //
  33 // The above copyright notice and this permission notice shall be
  34 // included in all copies or substantial portions of the Software.
  35 //
  36 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  37 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  38 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  39 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  40 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  41 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  42 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  43 //
  44
  45 using System.Globalization;
  46 using System.Runtime.Serialization;
  47 using System.Runtime.ConstrainedExecution;
  48
  49 namespace System
  50 {
  51         [Serializable]
  52         [System.Runtime.InteropServices.ComVisible (true)]
  53         public unsafe struct IntPtr : ISerializable
  54         {
  55                 private void *m_value;
  56
  57                 public static readonly IntPtr Zero;
  58
  59                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
  60                 public IntPtr (int value)
  61                 {
  62                         m_value = (void *) value;
  63                 }
  64
  65                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
  66                 public IntPtr (long value)
  67                 {
  68                         /* FIXME: Needs to figure the exact check which works on all architectures */
  69                         /*
  70                         if (((value >> 32 > 0) || (value < 0)) && (IntPtr.Size < 8)) {
  71                                 throw new OverflowException (
  72                                         Locale.GetText ("This isn't a 64bits machine."));
  73                         }
  74                         */
  75
  76                         m_value = (void *) value;
  77                 }
  78
  79                 [CLSCompliant (false)]
  80                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
  81                 unsafe public IntPtr (void *value)
  82                 {
  83                         m_value = value;
  84                 }
  85
  86                 private IntPtr (SerializationInfo info, StreamingContext context)
  87                 {
  88                         long savedValue = info.GetInt64 ("value");
  89                         m_value = (void *) savedValue;
  90                 }
  91
  92                 public static int Size {
  93                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
  94                         get {
  95                                 return sizeof (void *);
  96                         }
  97                 }
  98
  99                 void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
 100                 {
 101                         if (info == null)
 102                                 throw new ArgumentNullException ("info");
 103
 104                         info.AddValue ("value", ToInt64 ());
 105                 }
 106
 107                 public override bool Equals (object obj)
 108                 {
 109                         if (!(obj is System.IntPtr))
 110                                 return false;
 111
 112                         return ((IntPtr) obj).m_value == m_value;
 113                 }
 114
 115                 public override int GetHashCode ()
 116                 {
 117                         return (int) m_value;
 118                 }
 119
 120                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 121                 public int ToInt32 ()
 122                 {
 123                         return (int) m_value;
 124                 }
 125
 126                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 127                 public long ToInt64 ()
 128                 {
 129                         // pointer to long conversion is done using conv.u8 by the compiler
 130                         if (Size == 4)
 131                                 return (long)(int)m_value;
 132                         else
 133                                 return (long)m_value;
 134                 }
 135
 136                 [CLSCompliant (false)]
 137                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 138                 unsafe public void *ToPointer ()
 139                 {
 140                         return m_value;
 141                 }
 142
 143                 override public string ToString ()
 144                 {
 145                         return ToString (null);
 146                 }
 147
 148                 public string ToString (string format)
 149                 {
 150                         if (Size == 4)
 151                                 return ((int) m_value).ToString (format);
 152                         else
 153                                 return ((long) m_value).ToString (format);
 154                 }
 155
 156                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 157                 public static bool operator == (IntPtr value1, IntPtr value2)
 158                 {
 159                         return (value1.m_value == value2.m_value);
 160                 }
 161
 162                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 163                 public static bool operator != (IntPtr value1, IntPtr value2)
 164                 {
 165                         return (value1.m_value != value2.m_value);
 166                 }
 167
 168                 [ReliabilityContractAttribute (Consistency.MayCorruptInstance, Cer.MayFail)]
 169                 public static explicit operator IntPtr (int value)
 170                 {
 171                         return new IntPtr (value);
 172                 }
 173
 174                 [ReliabilityContractAttribute (Consistency.MayCorruptInstance, Cer.MayFail)]
 175                 public static explicit operator IntPtr (long value)
 176                 {
 177                         return new IntPtr (value);
 178                 }
 179
 180                 [ReliabilityContractAttribute (Consistency.MayCorruptInstance, Cer.MayFail)]
 181                 [CLSCompliant (false)]
 182                 unsafe public static explicit operator IntPtr (void *value)
 183                 {
 184                         return new IntPtr (value);
 185                 }
 186
 187                 public static explicit operator int (IntPtr value)
 188                 {
 189                         return (int) value.m_value;
 190                 }
 191
 192                 public static explicit operator long (IntPtr value)
 193                 {
 194                         return value.ToInt64 ();
 195                 }
 196
 197                 [CLSCompliant (false)]
 198                 unsafe public static explicit operator void * (IntPtr value)
 199                 {
 200                         return value.m_value;
 201                 }
 202
 203 #if NET_4_0
 204                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
 205                 public static IntPtr Add (IntPtr pointer, int offset)
 206                 {
 207                         return (IntPtr) (unchecked (((byte *) pointer) + offset));
 208                 }
 209
 210                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
 211                 public static IntPtr Subtract (IntPtr pointer, int offset)
 212                 {
 213                         return (IntPtr) (unchecked (((byte *) pointer) - offset));
 214                 }
 215
 216                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
 217                 public static IntPtr operator + (IntPtr pointer, int offset)
 218                 {
 219                         return (IntPtr) (unchecked (((byte *) pointer) + offset));
 220                 }
 221
 222                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
 223                 public static IntPtr operator - (IntPtr pointer, int offset)
 224                 {
 225                         return (IntPtr) (unchecked (((byte *) pointer) - offset));
 226                 }
 227 #endif
 228         }
 229 }