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 #region Constructor
  54                 protected UnmanagedMemoryStream()
  55                 {
  56                         fileaccess = FileAccess.Read;
  57                         initial_position = 0;
  58                         canseek = true;
  59                         closed = false;
  60                         current_position = initial_position;
  61                 }
  62
  63                 public unsafe UnmanagedMemoryStream (byte *pointer, long length)
  64                 {
  65                         if (pointer == null)
  66                                 throw new ArgumentNullException("pointer");
  67                         if (length < 0)
  68                                 throw new ArgumentOutOfRangeException("length", "Non-negative number required.");
  69                         fileaccess = FileAccess.Read;
  70                         this.length = length;
  71                         capacity = length;
  72                         initial_position = 0;
  73                         current_position = initial_position;
  74                         canseek = true;
  75                         closed = false;
  76                         initial_pointer = new IntPtr((void*)pointer);
  77                 }
  78
  79                 public unsafe UnmanagedMemoryStream (byte *pointer, long length, long capacity, FileAccess access)
  80                 {
  81                         if (pointer == null)
  82                                 throw new ArgumentNullException("pointer");
  83                         if (length < 0)
  84                                 throw new ArgumentOutOfRangeException("length", "Non-negative number required.");
  85                         if (capacity < 0)
  86                                 throw new ArgumentOutOfRangeException("capacity", "Non-negative number required.");
  87                         if (length > capacity)
  88                                 throw new ArgumentOutOfRangeException("length", "The length cannot be greater than the capacity.");
  89                         if (!Enum.IsDefined (typeof (FileAccess), access))
  90                                 throw new ArgumentOutOfRangeException ("access", "Enum value was out of legal range.");
  91                         fileaccess = access;
  92                         this.length = length;
  93                         this.capacity = capacity;
  94                         initial_position = 0;
  95                         current_position = initial_position;
  96                         canseek = true;
  97                         initial_pointer = new IntPtr ((void*)pointer);
  98                         closed = false;
  99                         fileaccess = access;
 100                 }
 101 #endregion
 102
 103 #region Properties
 104                 public override bool CanRead {
 105                         get {
 106                                 if (closed)
 107                                         return false;
 108                                 return (fileaccess == FileAccess.Read || fileaccess == FileAccess.ReadWrite);
 109                         }
 110                 }
 111
 112                 public override bool CanSeek {
 113                         get {
 114                                 return !closed;
 115                         }
 116                 }
 117
 118                 public override bool CanWrite {
 119                         get {
 120                                 if (closed)
 121                                         return (false);
 122                                 return (fileaccess == FileAccess.Write || fileaccess == FileAccess.ReadWrite);
 123                         }
 124                 }
 125                 public long Capacity {
 126                         get {
 127                                 if (closed)
 128                                         throw new ObjectDisposedException("The stream is closed");
 129                                 else
 130                                         return (capacity);
 131                         }
 132                 }
 133                 public override long Length {
 134                         get {
 135                                 if (closed)
 136                                         throw new ObjectDisposedException("The stream is closed");
 137                                 else
 138                                         return (length);
 139                         }
 140                 }
 141                 public override long Position {
 142                         get {
 143                                 if (closed)
 144                                         throw new ObjectDisposedException("The stream is closed");
 145                                 return (current_position);
 146                         }
 147                         set {
 148                                 if (closed)
 149                                         throw new ObjectDisposedException("The stream is closed");
 150                                 if (value < 0)
 151                                         throw new ArgumentOutOfRangeException("value", "Non-negative number required.");
 152                                 if (value > (long)Int32.MaxValue)
 153                                         throw new ArgumentOutOfRangeException("value", "The position is larger than Int32.MaxValue.");
 154                                 current_position = value;
 155                         }
 156                 }
 157
 158                 public unsafe byte* PositionPointer {
 159                         get {
 160                                 throw new NotImplementedException("Error");
 161                         }
 162                         set {
 163                                 throw new NotImplementedException("Error");
 164                         }
 165                 }
 166 #endregion
 167
 168 #region Methods
 169                 public override int Read ([InAttribute] [OutAttribute] byte[] buffer, int offset, int count)
 170                          {
 171                                 if (closed)
 172                                         throw new ObjectDisposedException("The stream is closed");
 173
 174                                 if (buffer == null)
 175                                         throw new ArgumentNullException("buffer");
 176                                 if (offset < 0)
 177                                         throw new ArgumentOutOfRangeException("offset", "Non-negative number required.");
 178                                 if (count < 0)
 179                                         throw new ArgumentOutOfRangeException("count", "Non-negative number required.");
 180                                 if ((buffer.Length - offset) < count)
 181                                         throw new ArgumentException("The length of the buffer array minus the offset parameter is less than the count parameter");
 182
 183                                 if (fileaccess == FileAccess.Write)
 184                                         throw new NotSupportedException("Stream does not support reading");
 185                                 else {
 186                                         if (current_position >= length)
 187                                                 return (0);
 188                                         else {
 189                                                 int progress = current_position + count < length ? count : (int) (length - current_position);
 190                                                 for (int i = 0; i < progress; i++)
 191                                                         buffer [offset + i] = Marshal.ReadByte (initial_pointer, (int) current_position++);
 192                                                 return progress;
 193                                         }
 194                                 }
 195                         }
 196                 public override int ReadByte () {
 197                         if (closed)
 198                                 throw new ObjectDisposedException("The stream is closed");
 199
 200                         if (fileaccess== FileAccess.Write)
 201                                 throw new NotSupportedException("Stream does not support reading");
 202                         else {
 203                                 if (current_position >= length)
 204                                         return (-1);
 205                                 return (int) Marshal.ReadByte(initial_pointer, (int) current_position++);
 206                         }
 207                 }
 208                 public override long Seek (long offset, SeekOrigin loc) {
 209                         if (closed)
 210                                 throw new ObjectDisposedException("The stream is closed");
 211
 212                         long refpoint;
 213                         switch(loc) {
 214                         case SeekOrigin.Begin:
 215                                 if (offset < 0)
 216                                         throw new IOException("An attempt was made to seek before the beginning of the stream");
 217                                 refpoint = initial_position;
 218                                 break;
 219                         case SeekOrigin.Current:
 220                                 refpoint = current_position;
 221                                 break;
 222                         case SeekOrigin.End:
 223                                 refpoint = length;
 224                                 break;
 225                         default:
 226                                 throw new ArgumentException("Invalid SeekOrigin option");
 227                         }
 228                         refpoint += (int)offset;
 229                         if (refpoint < initial_position)
 230                                 throw new IOException("An attempt was made to seek before the beginning of the stream");
 231                         current_position = refpoint;
 232                         return(current_position);
 233                 }
 234
 235                 public override void SetLength (long value)
 236                 {
 237                         if (closed)
 238                                 throw new ObjectDisposedException("The stream is closed");
 239                         if (value < 0)
 240                                 throw new ArgumentOutOfRangeException("length", "Non-negative number required.");
 241                         if (value > capacity)
 242                                 throw new IOException ("Unable to expand length of this stream beyond its capacity.");
 243                         if (fileaccess == FileAccess.Read)
 244                                 throw new NotSupportedException ("Stream does not support writing.");
 245                         length = value;
 246                         if (length < current_position)
 247                                 current_position = length;
 248                 }
 249
 250                 public override void Flush ()
 251                 {
 252                         if (closed)
 253                                 throw new ObjectDisposedException("The stream is closed");
 254                         //This method performs no action for this class
 255                         //but is included as part of the Stream base class
 256                 }
 257
 258                 protected override void Dispose (bool disposing)
 259                 {
 260
 261                         closed = true;
 262                 }
 263
 264                 public override void Write (byte[] buffer, int offset, int count)
 265                 {
 266                         if (closed)
 267                                 throw new ObjectDisposedException("The stream is closed");
 268                         if (buffer == null)
 269                                 throw new ArgumentNullException("The buffer parameter is a null reference");
 270                         if ((current_position + count) > capacity)
 271                                 throw new NotSupportedException ("Unable to expand length of this stream beyond its capacity.");
 272                         if (offset < 0)
 273                                 throw new ArgumentOutOfRangeException("offset", "Non-negative number required.");
 274                         if (count < 0)
 275                                 throw new ArgumentOutOfRangeException("count", "Non-negative number required.");
 276                         if ((buffer.Length - offset) < count)
 277                                 throw new ArgumentException("The length of the buffer array minus the offset parameter is less than the count parameter");
 278                         if (fileaccess == FileAccess.Read)
 279                                 throw new NotSupportedException ("Stream does not support writing.");
 280                         else {
 281                                 unsafe {
 282                                         // use Marshal.WriteByte since that allow us to start writing
 283                                         // from the current position
 284                                         for (int i = 0; i < count; i++)
 285                                                 Marshal.WriteByte (initial_pointer, (int) current_position++, buffer [offset + i]);
 286
 287                                         if (current_position > length)
 288                                                 length = current_position;
 289                                 }
 290                         }
 291                 }
 292
 293                 public override void WriteByte (byte value)
 294                  {
 295                         if (closed)
 296                                 throw new ObjectDisposedException("The stream is closed");
 297
 298                         if (current_position == capacity)
 299                                 throw new NotSupportedException("The current position is at the end of the capacity of the stream");
 300                         if (fileaccess == FileAccess.Read)
 301                                 throw new NotSupportedException("Stream does not support writing.");
 302                         else {
 303                                 unsafe {
 304                                         Marshal.WriteByte(initial_pointer, (int)current_position, value);
 305                                         current_position++;
 306                                         if (current_position > length)
 307                                                 length = current_position;
 308                                 }
 309                         }
 310                 }
 311
 312                 protected unsafe void Initialize (byte* pointer, long length,
 313                                                   long capacity,
 314                                                   FileAccess access)
 315                 {
 316                         fileaccess = access;
 317                         this.length = length;
 318                         this.capacity = capacity;
 319                         initial_position = 0;
 320                         current_position = initial_position;
 321                         canseek = true;
 322                         initial_pointer = new IntPtr ((void *)pointer);
 323                         closed = false;
 324                 }
 325 #endregion
 326         }
 327 }
 328 #endif
 329