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

   1 //\r
   2 // System.IO.StreamWriter.cs\r
   3 //\r
   4 // Authors:\r
   5 //   Dietmar Maurer (dietmar@ximian.com)\r
   6 //   Paolo Molaro (lupus@ximian.com)\r
   7 //   Marek Safar (marek.safar@gmail.com)\r
   8 //\r
   9 // (C) Ximian, Inc.  http://www.ximian.com\r
  10 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)\r
  11 // Copyright 2011 Xamarin Inc.\r
  12 //\r
  13 // Permission is hereby granted, free of charge, to any person obtaining\r
  14 // a copy of this software and associated documentation files (the\r
  15 // "Software"), to deal in the Software without restriction, including\r
  16 // without limitation the rights to use, copy, modify, merge, publish,\r
  17 // distribute, sublicense, and/or sell copies of the Software, and to\r
  18 // permit persons to whom the Software is furnished to do so, subject to\r
  19 // the following conditions:\r
  20 // \r
  21 // The above copyright notice and this permission notice shall be\r
  22 // included in all copies or substantial portions of the Software.\r
  23 // \r
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,\r
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF\r
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND\r
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE\r
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION\r
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION\r
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\r
  31 //\r
  32 \r
  33 using System.Text;\r
  34 using System.Runtime.InteropServices;\r
  35 #if NET_4_5
  36 using System.Threading.Tasks;
  37 #endif\r
  38 \r
  39 namespace System.IO {\r
  40         \r
  41         [Serializable]\r
  42         [ComVisible (true)]\r
  43         public class StreamWriter : TextWriter {\r
  44 \r
  45                 private Encoding internalEncoding;\r
  46 \r
  47                 private Stream internalStream;\r
  48 \r
  49                 private const int DefaultBufferSize = 1024;\r
  50                 private const int DefaultFileBufferSize = 4096;\r
  51                 private const int MinimumBufferSize = 256;\r
  52 \r
  53                 private byte[] byte_buf;\r
  54                 private char[] decode_buf;\r
  55                 private int byte_pos;\r
  56                 private int decode_pos;\r
  57 \r
  58                 private bool iflush;\r
  59                 private bool DisposedAlready;\r
  60                 private bool preamble_done;\r
  61 \r
  62 #if NET_4_5\r
  63                 readonly bool leave_open;\r
  64                 Task async_task;\r
  65 #endif\r
  66 \r
  67                 public new static readonly StreamWriter Null = new StreamWriter (Stream.Null, Encoding.UTF8Unmarked, 1);\r
  68 \r
  69                 public StreamWriter (Stream stream)\r
  70                         : this (stream, Encoding.UTF8Unmarked, DefaultBufferSize) {}\r
  71 \r
  72                 public StreamWriter (Stream stream, Encoding encoding)\r
  73                         : this (stream, encoding, DefaultBufferSize) {}\r
  74 \r
  75                 internal void Initialize(Encoding encoding, int bufferSize) {\r
  76                         internalEncoding = encoding;\r
  77                         decode_pos = byte_pos = 0;\r
  78                         int BufferSize = Math.Max(bufferSize, MinimumBufferSize);\r
  79                         decode_buf = new char [BufferSize];\r
  80                         byte_buf = new byte [encoding.GetMaxByteCount (BufferSize)];\r
  81 \r
  82                         // Fixes bug http://bugzilla.ximian.com/show_bug.cgi?id=74513\r
  83                         if (internalStream.CanSeek && internalStream.Position > 0)\r
  84                                 preamble_done = true;\r
  85                 }\r
  86 \r
  87 #if NET_4_5\r
  88                 public StreamWriter (Stream stream, Encoding encoding, int bufferSize)\r
  89                         : this (stream, encoding, bufferSize, false)\r
  90                 {\r
  91                 }\r
  92                 \r
  93                 public StreamWriter (Stream stream, Encoding encoding, int bufferSize, bool leaveOpen)\r
  94 #else\r
  95                 const bool leave_open = false;\r
  96 \r
  97                 public StreamWriter (Stream stream, Encoding encoding, int bufferSize)\r
  98 #endif\r
  99                 {\r
 100                         if (null == stream)\r
 101                                 throw new ArgumentNullException("stream");\r
 102                         if (null == encoding)\r
 103                                 throw new ArgumentNullException("encoding");\r
 104                         if (bufferSize <= 0)\r
 105                                 throw new ArgumentOutOfRangeException("bufferSize");\r
 106                         if (!stream.CanWrite)\r
 107                                 throw new ArgumentException ("Can not write to stream");\r
 108 \r
 109 #if NET_4_5\r
 110                         leave_open = leaveOpen;\r
 111 #endif\r
 112                         internalStream = stream;\r
 113 \r
 114                         Initialize(encoding, bufferSize);\r
 115                 }\r
 116 \r
 117                 public StreamWriter (string path)\r
 118                         : this (path, false, Encoding.UTF8Unmarked, DefaultFileBufferSize) {}\r
 119 \r
 120                 public StreamWriter (string path, bool append)\r
 121                         : this (path, append, Encoding.UTF8Unmarked, DefaultFileBufferSize) {}\r
 122 \r
 123                 public StreamWriter (string path, bool append, Encoding encoding)\r
 124                         : this (path, append, encoding, DefaultFileBufferSize) {}\r
 125 \r
 126                 public StreamWriter (string path, bool append, Encoding encoding, int bufferSize)\r
 127                 {\r
 128                         if (null == encoding)\r
 129                                 throw new ArgumentNullException("encoding");\r
 130                         if (bufferSize <= 0)\r
 131                                 throw new ArgumentOutOfRangeException("bufferSize");\r
 132 \r
 133                         FileMode mode;\r
 134 \r
 135                         if (append)\r
 136                                 mode = FileMode.Append;\r
 137                         else\r
 138                                 mode = FileMode.Create;\r
 139                         \r
 140                         internalStream = new FileStream (path, mode, FileAccess.Write, FileShare.Read);\r
 141 \r
 142                         if (append)\r
 143                                 internalStream.Position = internalStream.Length;\r
 144                         else\r
 145                                 internalStream.SetLength (0);\r
 146 \r
 147                         Initialize(encoding, bufferSize);\r
 148                 }\r
 149 \r
 150                 public virtual bool AutoFlush {\r
 151                         get {\r
 152                                 return iflush;\r
 153                         }\r
 154                         set {\r
 155                                 iflush = value;\r
 156                                 if (iflush)\r
 157                                         Flush ();\r
 158                         }\r
 159                 }\r
 160 \r
 161                 public virtual Stream BaseStream {\r
 162                         get {\r
 163                                 return internalStream;\r
 164                         }\r
 165                 }\r
 166 \r
 167                 public override Encoding Encoding {\r
 168                         get {\r
 169                                 return internalEncoding;\r
 170                         }\r
 171                 }\r
 172 \r
 173                 protected override void Dispose (bool disposing) \r
 174                 {\r
 175                         Exception exc = null;\r
 176                         if (!DisposedAlready && disposing && internalStream != null && !leave_open) {\r
 177                                 try {\r
 178                                         Flush();\r
 179                                 } catch (Exception e) {\r
 180                                         exc = e;\r
 181                                 }\r
 182                                 DisposedAlready = true;\r
 183                                 try {\r
 184                                         internalStream.Close ();\r
 185                                 } catch (Exception e) {\r
 186                                         if (exc == null)\r
 187                                                 exc = e;\r
 188                                 }\r
 189                         }\r
 190 \r
 191                         internalStream = null;\r
 192                         byte_buf = null;\r
 193                         internalEncoding = null;\r
 194                         decode_buf = null;\r
 195                         if (exc != null)\r
 196                                 throw exc;\r
 197                 }\r
 198 \r
 199                 public override void Flush ()\r
 200                 {\r
 201                         CheckState ();\r
 202 \r
 203                         Decode ();\r
 204                         if (byte_pos > 0) {\r
 205                                 FlushBytes ();\r
 206                                 internalStream.Flush ();\r
 207                         }\r
 208                 }\r
 209 \r
 210                 // how the speedup works:\r
 211                 // the Write () methods simply copy the characters in a buffer of chars (decode_buf)\r
 212                 // Decode () is called when the buffer is full or we need to flash.\r
 213                 // Decode () will use the encoding to get the bytes and but them inside\r
 214                 // byte_buf. From byte_buf the data is finally outputted to the stream.\r
 215                 void FlushBytes () \r
 216                 {\r
 217                         // write the encoding preamble only at the start of the stream\r
 218                         if (!preamble_done && byte_pos > 0) {\r
 219                                 byte[] preamble = internalEncoding.GetPreamble ();\r
 220                                 if (preamble.Length > 0)\r
 221                                         internalStream.Write (preamble, 0, preamble.Length);\r
 222                                 preamble_done = true;\r
 223                         }\r
 224                         internalStream.Write (byte_buf, 0, byte_pos);\r
 225                         byte_pos = 0;\r
 226                 }\r
 227                 \r
 228                 void Decode () \r
 229                 {\r
 230                         if (byte_pos > 0)\r
 231                                 FlushBytes ();\r
 232                         if (decode_pos > 0) {\r
 233                                 int len = internalEncoding.GetBytes (decode_buf, 0, decode_pos, byte_buf, byte_pos);\r
 234                                 byte_pos += len;\r
 235                                 decode_pos = 0;\r
 236                         }\r
 237                 }\r
 238                 \r
 239                 public override void Write (char[] buffer, int index, int count) \r
 240                 {\r
 241                         if (buffer == null)\r
 242                                 throw new ArgumentNullException ("buffer");\r
 243                         if (index < 0)\r
 244                                 throw new ArgumentOutOfRangeException ("index", "< 0");\r
 245                         if (count < 0)\r
 246                                 throw new ArgumentOutOfRangeException ("count", "< 0");\r
 247                         // re-ordered to avoid possible integer overflow\r
 248                         if (index > buffer.Length - count)\r
 249                                 throw new ArgumentException ("index + count > buffer.Length");\r
 250 \r
 251                         CheckState ();\r
 252 \r
 253                         LowLevelWrite (buffer, index, count);\r
 254                         if (iflush)\r
 255                                 Flush();\r
 256                 }\r
 257                 \r
 258                 void LowLevelWrite (char[] buffer, int index, int count)\r
 259                 {\r
 260                         while (count > 0) {\r
 261                                 int todo = decode_buf.Length - decode_pos;\r
 262                                 if (todo == 0) {\r
 263                                         Decode ();\r
 264                                         todo = decode_buf.Length;\r
 265                                 }\r
 266                                 if (todo > count)\r
 267                                         todo = count;\r
 268                                 Buffer.BlockCopy (buffer, index * 2, decode_buf, decode_pos * 2, todo * 2);\r
 269                                 count -= todo;\r
 270                                 index += todo;\r
 271                                 decode_pos += todo;\r
 272                         }\r
 273                 }\r
 274                 \r
 275                 void LowLevelWrite (string s)\r
 276                 {\r
 277                         int count = s.Length;\r
 278                         int index = 0;\r
 279                         while (count > 0) {\r
 280                                 int todo = decode_buf.Length - decode_pos;\r
 281                                 if (todo == 0) {\r
 282                                         Decode ();\r
 283                                         todo = decode_buf.Length;\r
 284                                 }\r
 285                                 if (todo > count)\r
 286                                         todo = count;\r
 287                                 \r
 288                                 for (int i = 0; i < todo; i ++)\r
 289                                         decode_buf [i + decode_pos] = s [i + index];\r
 290                                 \r
 291                                 count -= todo;\r
 292                                 index += todo;\r
 293                                 decode_pos += todo;\r
 294                         }\r
 295                 }\r
 296 \r
 297                 public override void Write (char value)\r
 298                 {\r
 299                         CheckState ();\r
 300 \r
 301                         // the size of decode_buf is always > 0 and\r
 302                         // we check for overflow right away\r
 303                         if (decode_pos >= decode_buf.Length)\r
 304                                 Decode ();\r
 305                         decode_buf [decode_pos++] = value;\r
 306                         if (iflush)\r
 307                                 Flush ();\r
 308                 }\r
 309 \r
 310                 public override void Write (char[] buffer)\r
 311                 {\r
 312                         CheckState ();\r
 313 \r
 314                         if (buffer != null)\r
 315                                 LowLevelWrite (buffer, 0, buffer.Length);\r
 316                         if (iflush)\r
 317                                 Flush ();\r
 318                 }\r
 319 \r
 320                 public override void Write (string value) \r
 321                 {\r
 322                         CheckState ();\r
 323 \r
 324                         if (value != null)\r
 325                                 LowLevelWrite (value);\r
 326                         \r
 327                         if (iflush)\r
 328                                 Flush ();\r
 329                 }\r
 330 \r
 331                 public override void Close()\r
 332                 {\r
 333                         Dispose (true);\r
 334                 }\r
 335 \r
 336                 ~StreamWriter ()\r
 337                 {\r
 338                         Dispose(false);\r
 339                 }\r
 340 \r
 341                 void CheckState ()\r
 342                 {\r
 343                         if (DisposedAlready)\r
 344                                 throw new ObjectDisposedException ("StreamWriter");\r
 345 \r
 346 #if NET_4_5\r
 347                         if (async_task != null && async_task.IsCompleted)\r
 348                                 throw new InvalidOperationException ();\r
 349 #endif\r
 350                 }\r
 351 \r
 352 #if NET_4_5\r
 353                 public override Task FlushAsync ()\r
 354                 {\r
 355                         CheckState ();\r
 356                         return async_task = base.FlushAsync ();\r
 357                 }\r
 358 \r
 359                 public override Task WriteAsync (char value)\r
 360                 {\r
 361                         CheckState ();\r
 362                         return async_task = base.WriteAsync (value);\r
 363                 }\r
 364 \r
 365                 public override Task WriteAsync (char[] buffer, int index, int count)\r
 366                 {\r
 367                         CheckState ();\r
 368                         return async_task = base.WriteAsync (buffer, index, count);\r
 369                 }\r
 370 \r
 371                 public override Task WriteAsync (string value)\r
 372                 {\r
 373                         CheckState ();\r
 374                         return async_task = base.WriteAsync (value);\r
 375                 }\r
 376 \r
 377                 public override Task WriteLineAsync ()\r
 378                 {\r
 379                         CheckState ();\r
 380                         return async_task = base.WriteLineAsync ();\r
 381                 }\r
 382 \r
 383                 public override Task WriteLineAsync (char value)\r
 384                 {\r
 385                         CheckState ();\r
 386                         return async_task = base.WriteLineAsync (value);\r
 387                 }\r
 388 \r
 389                 public override Task WriteLineAsync (char[] buffer, int index, int count)\r
 390                 {\r
 391                         CheckState ();\r
 392                         return async_task = base.WriteLineAsync (buffer, index, count);\r
 393                 }\r
 394 \r
 395                 public override Task WriteLineAsync (string value)\r
 396                 {\r
 397                         CheckState ();\r
 398                         return async_task = base.WriteLineAsync (value);\r
 399                 }\r
 400 #endif\r
 401         }\r
 402 }\r