mcs/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 using System.Diagnostics.Contracts;
  49
  50 namespace System
  51 {
  52         [Serializable]
  53         [System.Runtime.InteropServices.ComVisible (true)]
  54         public unsafe struct IntPtr : ISerializable
  55         {
  56                 private void *m_value;
  57
  58                 public static readonly IntPtr Zero;
  59
  60                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
  61                 public IntPtr (int value)
  62                 {
  63                         m_value = (void *) value;
  64                 }
  65
  66                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
  67                 public IntPtr (long value)
  68                 {
  69                         /* FIXME: Needs to figure the exact check which works on all architectures */
  70                         /*
  71                         if (((value >> 32 > 0) || (value < 0)) && (IntPtr.Size < 8)) {
  72                                 throw new OverflowException (
  73                                         Locale.GetText ("This isn't a 64bits machine."));
  74                         }
  75                         */
  76
  77                         m_value = (void *) value;
  78                 }
  79
  80                 [CLSCompliant (false)]
  81                 [ReliabilityContract (Consistency.MayCorruptInstance, Cer.MayFail)]
  82                 unsafe public IntPtr (void *value)
  83                 {
  84                         m_value = value;
  85                 }
  86
  87                 private IntPtr (SerializationInfo info, StreamingContext context)
  88                 {
  89                         long savedValue = info.GetInt64 ("value");
  90                         m_value = (void *) savedValue;
  91                 }
  92
  93                 public static int Size {
  94                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
  95                         get {
  96                                 return sizeof (void *);
  97                         }
  98                 }
  99
 100                 void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
 101                 {
 102                         if (info == null)
 103                                 throw new ArgumentNullException ("info");
 104
 105                         info.AddValue ("value", ToInt64 ());
 106                 }
 107
 108                 public override bool Equals (object obj)
 109                 {
 110                         if (!(obj is System.IntPtr))
 111                                 return false;
 112
 113                         return ((IntPtr) obj).m_value == m_value;
 114                 }
 115
 116                 public override int GetHashCode ()
 117                 {
 118                         return (int) m_value;
 119                 }
 120
 121                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 122                 public int ToInt32 ()
 123                 {
 124                         return (int) m_value;
 125                 }
 126
 127                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 128                 public long ToInt64 ()
 129                 {
 130                         // pointer to long conversion is done using conv.u8 by the compiler
 131                         if (Size == 4)
 132                                 return (long)(int)m_value;
 133                         else
 134                                 return (long)m_value;
 135                 }
 136
 137                 [CLSCompliant (false)]
 138                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 139                 unsafe public void *ToPointer ()
 140                 {
 141                         return m_value;
 142                 }
 143
 144                 override public string ToString ()
 145                 {
 146                         return ToString (null);
 147                 }
 148
 149                 public string ToString (string format)
 150                 {
 151                         if (Size == 4)
 152                                 return ((int) m_value).ToString (format, null);
 153                         else
 154                                 return ((long) m_value).ToString (format, null);
 155                 }
 156
 157                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 158                 public static bool operator == (IntPtr value1, IntPtr value2)
 159                 {
 160                         return (value1.m_value == value2.m_value);
 161                 }
 162
 163                 [ReliabilityContractAttribute (Consistency.WillNotCorruptState, Cer.Success)]
 164                 public static bool operator != (IntPtr value1, IntPtr value2)
 165                 {
 166                         return (value1.m_value != value2.m_value);
 167                 }
 168
 169                 [ReliabilityContractAttribute (Consistency.MayCorruptInstance, Cer.MayFail)]
 170                 public static explicit operator IntPtr (int value)
 171                 {
 172                         return new IntPtr (value);
 173                 }
 174
 175                 [ReliabilityContractAttribute (Consistency.MayCorruptInstance, Cer.MayFail)]
 176                 public static explicit operator IntPtr (long value)
 177                 {
 178                         return new IntPtr (value);
 179                 }
 180
 181                 [ReliabilityContractAttribute (Consistency.MayCorruptInstance, Cer.MayFail)]
 182                 [CLSCompliant (false)]
 183                 unsafe public static explicit operator IntPtr (void *value)
 184                 {
 185                         return new IntPtr (value);
 186                 }
 187
 188                 public static explicit operator int (IntPtr value)
 189                 {
 190                         return (int) value.m_value;
 191                 }
 192
 193                 public static explicit operator long (IntPtr value)
 194                 {
 195                         return value.ToInt64 ();
 196                 }
 197
 198                 [CLSCompliant (false)]
 199                 unsafe public static explicit operator void * (IntPtr value)
 200                 {
 201                         return value.m_value;
 202                 }
 203
 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
 228                 // fast way to compare IntPtr to (IntPtr)0 while IntPtr.Zero doesn't work due to slow statics access
 229                 [Pure]
 230                 [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
 231                 internal unsafe bool IsNull()
 232                 {
 233                         return m_value == null;
 234                 }
 235         }
 236 }