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
  30 using System;
  31 using System.IO;
  32 using System.Collections.Generic;
  33 using Microsoft.Win32.SafeHandles;
  34 using System.Runtime.ConstrainedExecution;
  35
  36 namespace System.Runtime.InteropServices
  37 {
  38         public abstract class SafeBuffer : SafeHandleZeroOrMinusOneIsInvalid, IDisposable {
  39                 ulong byte_length;
  40                 unsafe byte *last_byte;
  41                 bool inited;
  42
  43                 protected SafeBuffer (bool ownsHandle) : base (ownsHandle)
  44                 {
  45                 }
  46
  47                 [CLSCompliant (false)]
  48                 public void Initialize (ulong numBytes)
  49                 {
  50                         if (numBytes == 0)
  51                                 throw new ArgumentOutOfRangeException ("numBytes");
  52
  53                         inited = true;
  54                         byte_length = numBytes;
  55                         unsafe {
  56                                 last_byte = (byte *) (((byte *) handle) + numBytes);
  57                         }
  58                 }
  59
  60                 [CLSCompliant (false)]
  61                 public void Initialize (uint numElements, uint sizeOfEachElement)
  62                 {
  63                         Initialize (numElements * sizeOfEachElement);
  64                 }
  65
  66                 [CLSCompliant (false)]
  67                 public void Initialize<T> (uint numElements) where T : struct
  68                 {
  69                         Initialize (numElements, (uint)Marshal.SizeOf (typeof (T)));
  70                 }
  71
  72                 [CLSCompliant (false)]
  73                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
  74                 public unsafe void AcquirePointer (ref byte* pointer) {
  75                         if (!inited)
  76                                 throw new InvalidOperationException ();
  77                         bool success = false;
  78
  79                         DangerousAddRef (ref success);
  80                         if (success)
  81                                 pointer = (byte*)handle;
  82                 }
  83
  84                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.Success)]
  85                 public void ReleasePointer () {
  86                         if (!inited)
  87                                 throw new InvalidOperationException ();
  88                         DangerousRelease ();
  89                 }
  90
  91                 [CLSCompliant (false)]
  92                 public ulong ByteLength {
  93                         get {
  94                                 return byte_length;
  95                         }
  96                 }
  97
  98                 [CLSCompliant (false)]
  99                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
 100                 public T Read<T> (ulong byteOffset) where T : struct
 101                 {
 102                         if (!inited)
 103                                 throw new InvalidOperationException ();
 104
 105                         unsafe {
 106                                 byte *source = (((byte *) handle) + byteOffset);
 107                                 if (source >= last_byte || source + Marshal.SizeOf (typeof (T)) > last_byte){
 108                                         throw new ArgumentException ("byteOffset");
 109                                 }
 110
 111                                 return (T) Marshal.PtrToStructure ((IntPtr) source, typeof (T));
 112                         }
 113                 }
 114
 115                 [CLSCompliant (false)]
 116                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
 117                 public void ReadArray<T> (ulong byteOffset, T[] array, int index, int count) where T : struct {
 118                         if (!inited)
 119                                 throw new InvalidOperationException ();
 120
 121                         unsafe {
 122                                 int size = Marshal.SizeOf (typeof (T)) * count;
 123                                 byte *source = (((byte *) handle) + byteOffset);
 124                                 if (source >= last_byte || source + size > last_byte)
 125                                         throw new ArgumentException ("byteOffset");
 126
 127                                 Marshal.copy_from_unmanaged ((IntPtr) source, index, array, count);
 128                         }
 129                 }
 130
 131                 [CLSCompliant (false)]
 132                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
 133                 public void Write<T> (ulong byteOffset, T value) where T : struct {
 134                         if (!inited)
 135                                 throw new InvalidOperationException ();
 136
 137                         unsafe {
 138                                 byte *target = (((byte *) handle) + byteOffset);
 139                                 if (target >= last_byte || target + Marshal.SizeOf (typeof (T)) > last_byte)
 140                                         throw new ArgumentException ("byteOffset");
 141
 142                                 Marshal.StructureToPtr (value, (IntPtr) target, false);
 143                         }
 144                 }
 145
 146                 [CLSCompliant (false)]
 147                 [ReliabilityContract (Consistency.WillNotCorruptState, Cer.MayFail)]
 148                 public void WriteArray<T> (ulong byteOffset, T[] array, int index, int count) where T : struct
 149                 {
 150                         if (!inited)
 151                                 throw new InvalidOperationException ();
 152
 153                         unsafe {
 154                                 byte *target = ((byte *) handle) + byteOffset;
 155                                 int size = Marshal.SizeOf (typeof (T)) * count;
 156                                 if (target >= last_byte || target + size > last_byte)
 157                                         throw new ArgumentException ("would overrite");
 158
 159                                 Marshal.copy_to_unmanaged (array, index, (IntPtr) target, count);
 160                         }
 161                 }
 162         }
 163 }
 164