mcs/class/corlib/System.Runtime.InteropServices/SafeBuffer.cs

   1 //
   2 // SafeBuffer.cs
   3 //
   4 // Authors:
   5 //      Zoltan Varga (vargaz@gmail.com)
   6 //
   7 // Copyright (C) 2009, Novell, Inc (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 #if NET_4_0
  30
  31 using System;
  32 using System.IO;
  33 using System.Collections.Generic;
  34 using Microsoft.Win32.SafeHandles;
  35 using System.Runtime.ConstrainedExecution;
  36
  37 namespace System.Runtime.InteropServices
  38 {
  39         public abstract class SafeBuffer : SafeHandleZeroOrMinusOneIsInvalid, IDisposable {
  40                 ulong byte_length;
  41                 unsafe byte *last_byte;
  42                 bool inited;
  43
  44                 protected SafeBuffer (bool ownsHandle) : base (ownsHandle)
  45                 {
  46                 }
  47
  48                 [CLSCompliant (false)]
  49                 public void Initialize (ulong numBytes)
  50                 {
  51                         if (numBytes == 0)
  52                                 throw new ArgumentOutOfRangeException ("numBytes");
  53
  54                         inited = true;
  55                         byte_length = numBytes;
  56                         unsafe {
  57                                 last_byte = (byte *) (((byte *) handle) + numBytes);
  58                         }
  59                 }
  60
  61                 [CLSCompliant (false)]
  62                 public void Initialize (uint numElements, uint sizeOfEachElement)
  63                 {
  64                         Initialize (numElements * sizeOfEachElement);
  65                 }
  66
  67                 [CLSCompliant (false)]
  68                 public void Initialize<T> (uint numElements) where T : struct
  69                 {
  70                         Initialize (numElements, (uint)Marshal.SizeOf (typeof (T)));
  71                 }
  72
  73                 [CLSCompliant (false)]
  74                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
  75                 public unsafe void AcquirePointer (ref byte* pointer) {
  76                         if (!inited)
  77                                 throw new InvalidOperationException ();
  78                         bool success = false;
  79
  80                         DangerousAddRef (ref success);
  81                         if (success)
  82                                 pointer = (byte*)handle;
  83                 }
  84
  85                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.Success)]
  86                 public void ReleasePointer () {
  87                         if (!inited)
  88                                 throw new InvalidOperationException ();
  89                         DangerousRelease ();
  90                 }
  91
  92                 [CLSCompliant (false)]
  93                 public ulong ByteLength {
  94                         get {
  95                                 return byte_length;
  96                         }
  97                 }
  98
  99                 [CLSCompliant (false)]
 100                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
 101                 public T Read<T> (ulong byteOffset) where T : struct
 102                 {
 103                         if (!inited)
 104                                 throw new InvalidOperationException ();
 105
 106                         unsafe {
 107                                 byte *source = (((byte *) handle) + byteOffset);
 108                                 if (source >= last_byte || source + Marshal.SizeOf (typeof (T)) > last_byte){
 109                                         throw new ArgumentException ("byteOffset");
 110                                 }
 111
 112                                 return (T) Marshal.PtrToStructure ((IntPtr) source, typeof (T));
 113                         }
 114                 }
 115
 116                 [CLSCompliant (false)]
 117                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
 118                 public void ReadArray<T> (ulong byteOffset, T[] array, int index, int count) where T : struct {
 119                         if (!inited)
 120                                 throw new InvalidOperationException ();
 121
 122                         unsafe {
 123                                 int size = Marshal.SizeOf (typeof (T)) * count;
 124                                 byte *source = (((byte *) handle) + byteOffset);
 125                                 if (source >= last_byte || source + size > last_byte)
 126                                         throw new ArgumentException ("byteOffset");
 127
 128                                 Marshal.copy_from_unmanaged ((IntPtr) source, index, array, count);
 129                         }
 130                 }
 131
 132                 [CLSCompliant (false)]
 133                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
 134                 public void Write<T> (ulong byteOffset, T value) where T : struct {
 135                         if (!inited)
 136                                 throw new InvalidOperationException ();
 137
 138                         unsafe {
 139                                 byte *target = (((byte *) handle) + byteOffset);
 140                                 if (target >= last_byte || target + Marshal.SizeOf (typeof (T)) > last_byte)
 141                                         throw new ArgumentException ("byteOffset");
 142
 143                                 Marshal.StructureToPtr (value, (IntPtr) target, false);
 144                         }
 145                 }
 146
 147                 [CLSCompliant (false)]
 148                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
 149                 public void WriteArray<T> (ulong byteOffset, T[] array, int index, int count) where T : struct
 150                 {
 151                         if (!inited)
 152                                 throw new InvalidOperationException ();
 153
 154                         unsafe {
 155                                 byte *target = ((byte *) handle) + byteOffset;
 156                                 int size = Marshal.SizeOf (typeof (T)) * count;
 157                                 if (target >= last_byte || target + size > last_byte)
 158                                         throw new ArgumentException ("would overrite");
 159
 160                                 Marshal.copy_to_unmanaged (array, index, (IntPtr) target, count);
 161                         }
 162                 }
 163         }
 164 }
 165
 166 #endif