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

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