mcs/class/System.Drawing/System.Drawing/ComIStreamWrapper.cs

   1 //
   2 // System.Drawing.ComIStreamWrapper.cs
   3 //
   4 // Author:
   5 //   Kornél Pál <http://www.kornelpal.hu/>
   6 //
   7 // Copyright (C) 2005 Kornél Pál
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32 using System.IO;
  33 using System.Reflection;
  34 using System.Runtime.InteropServices;
  35 #if NET_2_0
  36 using System.Runtime.InteropServices.ComTypes;
  37 using STATSTG = System.Runtime.InteropServices.ComTypes.STATSTG;
  38 #else
  39 using IStream = System.Runtime.InteropServices.UCOMIStream;
  40 #endif
  41
  42 namespace System.Drawing
  43 {
  44         // Stream to IStream wrapper for COM interop
  45         internal sealed class ComIStreamWrapper : IStream
  46         {
  47                 private const int STG_E_INVALIDFUNCTION = unchecked((int)0x80030001);
  48
  49                 private readonly Stream baseStream;
  50                 private long position = -1;
  51
  52                 internal ComIStreamWrapper(Stream stream)
  53                 {
  54                         baseStream = stream;
  55                 }
  56
  57                 private void SetSizeToPosition()
  58                 {
  59                         if (position != -1)
  60                         {
  61                                 if (position > baseStream.Length)
  62                                         baseStream.SetLength(position);
  63                                 baseStream.Position = position;
  64                                 position = -1;
  65                         }
  66                 }
  67
  68                 public void Read(byte[] pv, int cb, IntPtr pcbRead)
  69                 {
  70                         int read = 0;
  71
  72                         if (cb != 0)
  73                         {
  74                                 SetSizeToPosition();
  75
  76                                 read = baseStream.Read(pv, 0, cb);
  77                         }
  78
  79                         if (pcbRead != IntPtr.Zero)
  80                                 Marshal.WriteInt32(pcbRead, read);
  81                 }
  82
  83                 public void Write(byte[] pv, int cb, IntPtr pcbWritten)
  84                 {
  85                         if (cb != 0)
  86                         {
  87                                 SetSizeToPosition();
  88
  89                                 baseStream.Write(pv, 0, cb);
  90                         }
  91
  92                         if (pcbWritten != IntPtr.Zero)
  93                                 Marshal.WriteInt32(pcbWritten, cb);
  94                 }
  95
  96                 public void Seek(long dlibMove, int dwOrigin, IntPtr plibNewPosition)
  97                 {
  98                         long newPosition;
  99
 100                         if (baseStream.CanWrite)
 101                         {
 102                                 switch ((SeekOrigin)dwOrigin)
 103                                 {
 104                                         case SeekOrigin.Begin:
 105                                                 newPosition = dlibMove;
 106                                                 break;
 107                                         case SeekOrigin.Current:
 108                                                 if ((newPosition = position) == -1)
 109                                                         newPosition = baseStream.Position;
 110                                                 newPosition += dlibMove;
 111                                                 break;
 112                                         case SeekOrigin.End:
 113                                                 newPosition = baseStream.Length + dlibMove;
 114                                                 break;
 115                                         default:
 116                                                 throw new ExternalException(null, STG_E_INVALIDFUNCTION);
 117                                 }
 118
 119                                 if (newPosition > baseStream.Length)
 120                                         position = newPosition;
 121                                 else
 122                                 {
 123                                         baseStream.Position = newPosition;
 124                                         position = -1;
 125                                 }
 126                         }
 127                         else
 128                         {
 129                                 try
 130                                 {
 131                                         newPosition = baseStream.Seek(dlibMove, (SeekOrigin)dwOrigin);
 132                                 }
 133                                 catch (ArgumentException)
 134                                 {
 135                                         throw new ExternalException(null, STG_E_INVALIDFUNCTION);
 136                                 }
 137                                 position = -1;
 138                         }
 139
 140                         if (plibNewPosition != IntPtr.Zero)
 141                                 Marshal.WriteInt64(plibNewPosition, newPosition);
 142                 }
 143
 144                 public void SetSize(long libNewSize)
 145                 {
 146                         baseStream.SetLength(libNewSize);
 147                 }
 148
 149                 public void CopyTo(IStream pstm, long cb, IntPtr pcbRead, IntPtr pcbWritten)
 150                 {
 151                         byte[] buffer = new byte[4096];
 152                         long written = 0;
 153                         int read;
 154
 155                         if (cb != 0)
 156                         {
 157                                 SetSizeToPosition();
 158                                 do
 159                                 {
 160                                         int count = 4096;
 161
 162                                         if (written + 4096 > cb)
 163                                                 count = (int)(cb - written);
 164
 165                                         if ((read = baseStream.Read(buffer, 0, count)) == 0)
 166                                                 break;
 167                                         pstm.Write(buffer, read, IntPtr.Zero);
 168                                         written += read;
 169                                 } while (written < cb);
 170                         }
 171
 172                         if (pcbRead != IntPtr.Zero)
 173                                 Marshal.WriteInt64(pcbRead, written);
 174                         if (pcbWritten != IntPtr.Zero)
 175                                 Marshal.WriteInt64(pcbWritten, written);
 176                 }
 177
 178                 public void Commit(int grfCommitFlags)
 179                 {
 180                         baseStream.Flush();
 181                 }
 182
 183                 public void Revert()
 184                 {
 185                         throw new ExternalException(null, STG_E_INVALIDFUNCTION);
 186                 }
 187
 188                 public void LockRegion(long libOffset, long cb, int dwLockType)
 189                 {
 190                         throw new ExternalException(null, STG_E_INVALIDFUNCTION);
 191                 }
 192
 193                 public void UnlockRegion(long libOffset, long cb, int dwLockType)
 194                 {
 195                         throw new ExternalException(null, STG_E_INVALIDFUNCTION);
 196                 }
 197
 198                 public void Stat(out STATSTG pstatstg, int grfStatFlag)
 199                 {
 200                         pstatstg = new STATSTG();
 201                         pstatstg.cbSize = baseStream.Length;
 202                 }
 203
 204                 public void Clone(out IStream ppstm)
 205                 {
 206                         ppstm = null;
 207                         throw new ExternalException(null, STG_E_INVALIDFUNCTION);
 208                 }
 209         }
 210 }