mcs/class/corlib/System.IO/UnmanagedMemoryStream.cs

   1 //
   2 // System.IO.UnmanagedMemoryStream.cs
   3 //
   4 // Copyright (C) 2006 Sridhar Kulkarni, All Rights Reserved
   5 //
   6 // Authors:
   7 //      Sridhar Kulkarni (sridharkulkarni@gmail.com)
   8 //      Gert Driesen (drieseng@users.sourceforge.net)
   9 //
  10 // Copyright (C) 2005-2006 Novell, Inc (http://www.novell.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 #if NET_2_0
  33
  34 using System;
  35 using System.IO;
  36 using System.Runtime.InteropServices;
  37
  38 namespace System.IO
  39 {
  40         [CLSCompliantAttribute(false)]
  41         public class UnmanagedMemoryStream : Stream
  42         {
  43                 long length;
  44                 bool closed;
  45                 bool canseek = false;
  46                 long capacity;
  47                 FileAccess fileaccess;
  48                 IntPtr initial_pointer;
  49                 IntPtr pointer_position;
  50                 long initial_position;
  51                 long current_position;
  52
  53                 internal event EventHandler Closed;
  54
  55 #region Constructor
  56                 protected UnmanagedMemoryStream()
  57                 {
  58                         fileaccess = FileAccess.Read;
  59                         initial_position = 0;
  60                         canseek = true;
  61                         closed = false;
  62                         current_position = initial_position;
  63                 }
  64
  65                 public unsafe UnmanagedMemoryStream (byte *pointer, long length)
  66                 {
  67                         if (pointer == null)
  68                                 throw new ArgumentNullException("pointer");
  69                         if (length < 0)
  70                                 throw new ArgumentOutOfRangeException("length", "Non-negative number required.");
  71                         fileaccess = FileAccess.Read;
  72                         this.length = length;
  73                         capacity = length;
  74                         initial_position = 0;
  75                         current_position = initial_position;
  76                         canseek = true;
  77                         closed = false;
  78                         initial_pointer = new IntPtr((void*)pointer);
  79                 }
  80
  81                 public unsafe UnmanagedMemoryStream (byte *pointer, long length, long capacity, FileAccess access)
  82                 {
  83                         if (pointer == null)
  84                                 throw new ArgumentNullException("pointer");
  85                         if (length < 0)
  86                                 throw new ArgumentOutOfRangeException("length", "Non-negative number required.");
  87                         if (capacity < 0)
  88                                 throw new ArgumentOutOfRangeException("capacity", "Non-negative number required.");
  89                         if (length > capacity)
  90                                 throw new ArgumentOutOfRangeException("length", "The length cannot be greater than the capacity.");
  91                         if (!Enum.IsDefined (typeof (FileAccess), access))
  92                                 throw new ArgumentOutOfRangeException ("access", "Enum value was out of legal range.");
  93                         fileaccess = access;
  94                         this.length = length;
  95                         this.capacity = capacity;
  96                         initial_position = 0;
  97                         current_position = initial_position;
  98                         canseek = true;
  99                         initial_pointer = new IntPtr ((void*)pointer);
 100                         closed = false;
 101                         fileaccess = access;
 102                 }
 103 #endregion
 104
 105 #region Properties
 106                 public override bool CanRead {
 107                         get {
 108                                 if (closed)
 109                                         return false;
 110                                 return (fileaccess == FileAccess.Read || fileaccess == FileAccess.ReadWrite);
 111                         }
 112                 }
 113
 114                 public override bool CanSeek {
 115                         get {
 116                                 return !closed;
 117                         }
 118                 }
 119
 120                 public override bool CanWrite {
 121                         get {
 122                                 if (closed)
 123                                         return (false);
 124                                 return (fileaccess == FileAccess.Write || fileaccess == FileAccess.ReadWrite);
 125                         }
 126                 }
 127                 public long Capacity {
 128                         get {
 129                                 if (closed)
 130                                         throw new ObjectDisposedException("The stream is closed");
 131                                 else
 132                                         return (capacity);
 133                         }
 134                 }
 135                 public override long Length {
 136                         get {
 137                                 if (closed)
 138                                         throw new ObjectDisposedException("The stream is closed");
 139                                 else
 140                                         return (length);
 141                         }
 142                 }
 143                 public override long Position {
 144                         get {
 145                                 if (closed)
 146                                         throw new ObjectDisposedException("The stream is closed");
 147                                 return (current_position);
 148                         }
 149                         set {
 150                                 if (closed)
 151                                         throw new ObjectDisposedException("The stream is closed");
 152                                 if (value < 0)
 153                                         throw new ArgumentOutOfRangeException("value", "Non-negative number required.");
 154                                 if (value > (long)Int32.MaxValue)
 155                                         throw new ArgumentOutOfRangeException("value", "The position is larger than Int32.MaxValue.");
 156                                 current_position = value;
 157                         }
 158                 }
 159
 160                 public unsafe byte* PositionPointer {
 161                         get {
 162                                 throw new NotImplementedException("Error");
 163                         }
 164                         set {
 165                                 throw new NotImplementedException("Error");
 166                         }
 167                 }
 168 #endregion
 169
 170 #region Methods
 171                 public override int Read ([InAttribute] [OutAttribute] byte[] buffer, int offset, int count)
 172                          {
 173                                 if (closed)
 174                                         throw new ObjectDisposedException("The stream is closed");
 175
 176                                 if (buffer == null)
 177                                         throw new ArgumentNullException("buffer");
 178                                 if (offset < 0)
 179                                         throw new ArgumentOutOfRangeException("offset", "Non-negative number required.");
 180                                 if (count < 0)
 181                                         throw new ArgumentOutOfRangeException("count", "Non-negative number required.");
 182                                 if ((buffer.Length - offset) < count)
 183                                         throw new ArgumentException("The length of the buffer array minus the offset parameter is less than the count parameter");
 184
 185                                 if (fileaccess == FileAccess.Write)
 186                                         throw new NotSupportedException("Stream does not support reading");
 187                                 else {
 188                                         if (current_position >= length)
 189                                                 return (0);
 190                                         else {
 191                                                 int progress = current_position + count < length ? count : (int) (length - current_position);
 192                                                 for (int i = 0; i < progress; i++)
 193                                                         buffer [offset + i] = Marshal.ReadByte (initial_pointer, (int) current_position++);
 194                                                 return progress;
 195                                         }
 196                                 }
 197                         }
 198                 public override int ReadByte () {
 199                         if (closed)
 200                                 throw new ObjectDisposedException("The stream is closed");
 201
 202                         if (fileaccess== FileAccess.Write)
 203                                 throw new NotSupportedException("Stream does not support reading");
 204                         else {
 205                                 if (current_position >= length)
 206                                         return (-1);
 207                                 return (int) Marshal.ReadByte(initial_pointer, (int) current_position++);
 208                         }
 209                 }
 210                 public override long Seek (long offset, SeekOrigin loc) {
 211                         if (closed)
 212                                 throw new ObjectDisposedException("The stream is closed");
 213
 214                         long refpoint;
 215                         switch(loc) {
 216                         case SeekOrigin.Begin:
 217                                 if (offset < 0)
 218                                         throw new IOException("An attempt was made to seek before the beginning of the stream");
 219                                 refpoint = initial_position;
 220                                 break;
 221                         case SeekOrigin.Current:
 222                                 refpoint = current_position;
 223                                 break;
 224                         case SeekOrigin.End:
 225                                 refpoint = length;
 226                                 break;
 227                         default:
 228                                 throw new ArgumentException("Invalid SeekOrigin option");
 229                         }
 230                         refpoint += (int)offset;
 231                         if (refpoint < initial_position)
 232                                 throw new IOException("An attempt was made to seek before the beginning of the stream");
 233                         current_position = refpoint;
 234                         return(current_position);
 235                 }
 236
 237                 public override void SetLength (long value)
 238                 {
 239                         if (closed)
 240                                 throw new ObjectDisposedException("The stream is closed");
 241                         if (value < 0)
 242                                 throw new ArgumentOutOfRangeException("length", "Non-negative number required.");
 243                         if (value > capacity)
 244                                 throw new IOException ("Unable to expand length of this stream beyond its capacity.");
 245                         if (fileaccess == FileAccess.Read)
 246                                 throw new NotSupportedException ("Stream does not support writing.");
 247                         length = value;
 248                         if (length < current_position)
 249                                 current_position = length;
 250                 }
 251
 252                 public override void Flush ()
 253                 {
 254                         if (closed)
 255                                 throw new ObjectDisposedException("The stream is closed");
 256                         //This method performs no action for this class
 257                         //but is included as part of the Stream base class
 258                 }
 259
 260                 protected override void Dispose (bool disposing)
 261                 {
 262                         if (closed)
 263                                 return;
 264                         closed = true;
 265                         if (Closed != null)
 266                                 Closed (this, null);
 267                 }
 268
 269                 public override void Write (byte[] buffer, int offset, int count)
 270                 {
 271                         if (closed)
 272                                 throw new ObjectDisposedException("The stream is closed");
 273                         if (buffer == null)
 274                                 throw new ArgumentNullException("The buffer parameter is a null reference");
 275                         if ((current_position + count) > capacity)
 276                                 throw new NotSupportedException ("Unable to expand length of this stream beyond its capacity.");
 277                         if (offset < 0)
 278                                 throw new ArgumentOutOfRangeException("offset", "Non-negative number required.");
 279                         if (count < 0)
 280                                 throw new ArgumentOutOfRangeException("count", "Non-negative number required.");
 281                         if ((buffer.Length - offset) < count)
 282                                 throw new ArgumentException("The length of the buffer array minus the offset parameter is less than the count parameter");
 283                         if (fileaccess == FileAccess.Read)
 284                                 throw new NotSupportedException ("Stream does not support writing.");
 285                         else {
 286                                 unsafe {
 287                                         // use Marshal.WriteByte since that allow us to start writing
 288                                         // from the current position
 289                                         for (int i = 0; i < count; i++)
 290                                                 Marshal.WriteByte (initial_pointer, (int) current_position++, buffer [offset + i]);
 291
 292                                         if (current_position > length)
 293                                                 length = current_position;
 294                                 }
 295                         }
 296                 }
 297
 298                 public override void WriteByte (byte value)
 299                  {
 300                         if (closed)
 301                                 throw new ObjectDisposedException("The stream is closed");
 302
 303                         if (current_position == capacity)
 304                                 throw new NotSupportedException("The current position is at the end of the capacity of the stream");
 305                         if (fileaccess == FileAccess.Read)
 306                                 throw new NotSupportedException("Stream does not support writing.");
 307                         else {
 308                                 unsafe {
 309                                         Marshal.WriteByte(initial_pointer, (int)current_position, value);
 310                                         current_position++;
 311                                         if (current_position > length)
 312                                                 length = current_position;
 313                                 }
 314                         }
 315                 }
 316
 317                 protected unsafe void Initialize (byte* pointer, long length,
 318                                                   long capacity,
 319                                                   FileAccess access)
 320                 {
 321                         fileaccess = access;
 322                         this.length = length;
 323                         this.capacity = capacity;
 324                         initial_position = 0;
 325                         current_position = initial_position;
 326                         canseek = true;
 327                         initial_pointer = new IntPtr ((void *)pointer);
 328                         closed = false;
 329                 }
 330 #endregion
 331         }
 332 }
 333 #endif
 334