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 || BOOTSTRAP_NET_4_0
  30
  31 using System;
  32 using System.IO;
  33 using System.Collections.Generic;
  34 using Microsoft.Win32.SafeHandles;
  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                 public unsafe void AcquirePointer (ref byte* pointer) {
  74                         if (!inited)
  75                                 throw new InvalidOperationException ();
  76                         bool success = false;
  77
  78                         DangerousAddRef (ref success);
  79                         if (success)
  80                                 pointer = (byte*)handle;
  81                 }
  82
  83                 public void ReleasePointer () {
  84                         if (!inited)
  85                                 throw new InvalidOperationException ();
  86                         DangerousRelease ();
  87                 }
  88
  89                 [CLSCompliant (false)]
  90                 public ulong ByteLength {
  91                         get {
  92                                 return byte_length;
  93                         }
  94                 }
  95
  96                 [CLSCompliant (false)]
  97                 public T Read<T> (ulong byteOffset) where T : struct
  98                 {
  99                         if (!inited)
 100                                 throw new InvalidOperationException ();
 101
 102                         unsafe {
 103                                 byte *source = (((byte *) handle) + byteOffset);
 104                                 if (source >= last_byte || source + Marshal.SizeOf (typeof (T)) > last_byte){
 105                                         throw new ArgumentException ("byteOffset");
 106                                 }
 107
 108                                 return (T) Marshal.PtrToStructure ((IntPtr) source, typeof (T));
 109                         }
 110                 }
 111
 112                 [CLSCompliant (false)]
 113                 public void ReadArray<T> (ulong byteOffset, T[] array, int index, int count) where T : struct {
 114                         if (!inited)
 115                                 throw new InvalidOperationException ();
 116
 117                         unsafe {
 118                                 int size = Marshal.SizeOf (typeof (T)) * count;
 119                                 byte *source = (((byte *) handle) + byteOffset);
 120                                 if (source >= last_byte || source + size > last_byte)
 121                                         throw new ArgumentException ("byteOffset");
 122
 123                                 Marshal.copy_from_unmanaged ((IntPtr) source, index, array, count);
 124                         }
 125                 }
 126
 127                 [CLSCompliant (false)]
 128                 public void Write<T> (ulong byteOffset, T value) where T : struct {
 129                         if (!inited)
 130                                 throw new InvalidOperationException ();
 131
 132                         unsafe {
 133                                 byte *target = (((byte *) handle) + byteOffset);
 134                                 if (target >= last_byte || target + Marshal.SizeOf (typeof (T)) > last_byte)
 135                                         throw new ArgumentException ("byteOffset");
 136
 137                                 Marshal.StructureToPtr (value, (IntPtr) target, false);
 138                         }
 139                 }
 140
 141                 [CLSCompliant (false)]
 142                 public void WriteArray<T> (ulong byteOffset, T[] array, int index, int count) where T : struct
 143                 {
 144                         if (!inited)
 145                                 throw new InvalidOperationException ();
 146
 147                         unsafe {
 148                                 byte *target = ((byte *) handle) + byteOffset;
 149                                 int size = Marshal.SizeOf (typeof (T)) * count;
 150                                 if (target >= last_byte || target + size > last_byte)
 151                                         throw new ArgumentException ("would overrite");
 152
 153                                 Marshal.copy_to_unmanaged (array, index, (IntPtr) target, count);
 154                         }
 155                 }
 156         }
 157 }
 158
 159 #endif