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 //\r
   8 // (C) Ximian, Inc.  http://www.ximian.com\r
   9 //\r
  10 \r
  11 //\r
  12 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)\r
  13 //\r
  14 // Permission is hereby granted, free of charge, to any person obtaining\r
  15 // a copy of this software and associated documentation files (the\r
  16 // "Software"), to deal in the Software without restriction, including\r
  17 // without limitation the rights to use, copy, modify, merge, publish,\r
  18 // distribute, sublicense, and/or sell copies of the Software, and to\r
  19 // permit persons to whom the Software is furnished to do so, subject to\r
  20 // the following conditions:\r
  21 // \r
  22 // The above copyright notice and this permission notice shall be\r
  23 // included in all copies or substantial portions of the Software.\r
  24 // \r
  25 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,\r
  26 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF\r
  27 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND\r
  28 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE\r
  29 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION\r
  30 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION\r
  31 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.\r
  32 //\r
  33 \r
  34 using System.Text;\r
  35 using System;\r
  36 \r
  37 #if NET_2_0\r
  38 using System.Runtime.InteropServices;\r
  39 #endif\r
  40 \r
  41 namespace System.IO {\r
  42         \r
  43         [Serializable]\r
  44 #if NET_2_0\r
  45         [ComVisible (true)]\r
  46 #endif\r
  47         public class StreamWriter : TextWriter {\r
  48 \r
  49                 private Encoding internalEncoding;\r
  50 \r
  51                 private Stream internalStream;\r
  52                 private bool closed = false;\r
  53 \r
  54                 private bool iflush;\r
  55                 \r
  56                 private const int DefaultBufferSize = 1024;\r
  57                 private const int DefaultFileBufferSize = 4096;\r
  58                 private const int MinimumBufferSize = 256;\r
  59 \r
  60                 private byte[] byte_buf;\r
  61                 private int byte_pos;\r
  62                 private char[] decode_buf;\r
  63                 private int decode_pos;\r
  64 \r
  65                 private bool DisposedAlready = false;\r
  66                 private bool preamble_done = false;\r
  67 \r
  68                 public new static readonly StreamWriter Null = new StreamWriter (Stream.Null, Encoding.UTF8Unmarked, 0);\r
  69 \r
  70                 public StreamWriter (Stream stream)\r
  71                         : this (stream, Encoding.UTF8Unmarked, DefaultBufferSize) {}\r
  72 \r
  73                 public StreamWriter (Stream stream, Encoding encoding)\r
  74                         : this (stream, encoding, DefaultBufferSize) {}\r
  75 \r
  76                 internal void Initialize(Encoding encoding, int bufferSize) {\r
  77                         internalEncoding = encoding;\r
  78                         decode_pos = byte_pos = 0;\r
  79                         int BufferSize = Math.Max(bufferSize, MinimumBufferSize);\r
  80                         decode_buf = new char [BufferSize];\r
  81                         byte_buf = new byte [encoding.GetMaxByteCount (BufferSize)];\r
  82 \r
  83                         // Fixes bug http://bugzilla.ximian.com/show_bug.cgi?id=74513\r
  84                         if (internalStream.CanSeek && internalStream.Position > 0)\r
  85                                 preamble_done = true;\r
  86                 }\r
  87 \r
  88                 //[MonoTODO("Nothing is done with bufferSize")]\r
  89                 public StreamWriter (Stream stream, Encoding encoding, int bufferSize) {\r
  90                         if (null == stream)\r
  91                                 throw new ArgumentNullException("stream");\r
  92                         if (null == encoding)\r
  93                                 throw new ArgumentNullException("encoding");\r
  94                         if (bufferSize < 0)\r
  95                                 throw new ArgumentOutOfRangeException("bufferSize");\r
  96                         if (!stream.CanWrite)\r
  97                                 throw new ArgumentException("Can not write to stream", "stream");\r
  98 \r
  99                         internalStream = stream;\r
 100 \r
 101                         Initialize(encoding, bufferSize);\r
 102                 }\r
 103 \r
 104                 public StreamWriter (string path)\r
 105                         : this (path, false, Encoding.UTF8Unmarked, DefaultFileBufferSize) {}\r
 106 \r
 107                 public StreamWriter (string path, bool append)\r
 108                         : this (path, append, Encoding.UTF8Unmarked, DefaultFileBufferSize) {}\r
 109 \r
 110                 public StreamWriter (string path, bool append, Encoding encoding)\r
 111                         : this (path, append, encoding, DefaultFileBufferSize) {}\r
 112                 \r
 113                 public StreamWriter (string path, bool append, Encoding encoding, int bufferSize) {\r
 114                         if (null == path)\r
 115                                 throw new ArgumentNullException("path");\r
 116                         if (String.Empty == path)\r
 117                                 throw new ArgumentException("path cannot be empty string");\r
 118                         if (path.IndexOfAny (Path.InvalidPathChars) != -1)\r
 119                                 throw new ArgumentException("path contains invalid characters");\r
 120 \r
 121                         if (null == encoding)\r
 122                                 throw new ArgumentNullException("encoding");\r
 123                         if (bufferSize < 0)\r
 124                                 throw new ArgumentOutOfRangeException("bufferSize");\r
 125 \r
 126                         string DirName = Path.GetDirectoryName(path);\r
 127                         if (DirName != String.Empty && !Directory.Exists(DirName))\r
 128                                 throw new DirectoryNotFoundException();\r
 129 \r
 130                         FileMode mode;\r
 131 \r
 132                         if (append)\r
 133                                 mode = FileMode.Append;\r
 134                         else\r
 135                                 mode = FileMode.Create;\r
 136                         \r
 137                         internalStream = new FileStream (path, mode, FileAccess.Write, FileShare.Read);\r
 138 \r
 139                         if (append)\r
 140                                 internalStream.Position = internalStream.Length;\r
 141                         else\r
 142                                 internalStream.SetLength (0);\r
 143 \r
 144                         Initialize(encoding, bufferSize);\r
 145                 }\r
 146 \r
 147                 public virtual bool AutoFlush {\r
 148                         get {\r
 149                                 return iflush;\r
 150                         }\r
 151                         set {\r
 152                                 if (DisposedAlready)\r
 153                                         throw new ObjectDisposedException("StreamWriter");\r
 154                                 iflush = value;\r
 155 \r
 156                                 if (iflush) {\r
 157                                         Flush ();\r
 158                                 }\r
 159                         }\r
 160                 }\r
 161 \r
 162                 public virtual Stream BaseStream {\r
 163                         get {\r
 164                                 return internalStream;\r
 165                         }\r
 166                 }\r
 167 \r
 168                 public override Encoding Encoding {\r
 169                         get {\r
 170                                 return internalEncoding;\r
 171                         }\r
 172                 }\r
 173 \r
 174                 protected override void Dispose (bool disposing) \r
 175                 {\r
 176                         if (!DisposedAlready && disposing && internalStream != null) {\r
 177                                 Flush();\r
 178                                 DisposedAlready = true;\r
 179                                 internalStream.Close ();\r
 180                         }\r
 181 \r
 182                         internalStream = null;\r
 183                         byte_buf = null;\r
 184                         internalEncoding = null;\r
 185                         decode_buf = null;\r
 186                 }\r
 187 \r
 188                 public override void Flush ()\r
 189                 {\r
 190                         if (DisposedAlready)\r
 191                                 throw new ObjectDisposedException("StreamWriter");\r
 192 \r
 193                         Decode ();\r
 194                         if (byte_pos > 0) {\r
 195                                 FlushBytes ();\r
 196                                 internalStream.Flush ();\r
 197                         }\r
 198                 }\r
 199 \r
 200                 // how the speedup works:\r
 201                 // the Write () methods simply copy the characters in a buffer of chars (decode_buf)\r
 202                 // Decode () is called when the buffer is full or we need to flash.\r
 203                 // Decode () will use the encoding to get the bytes and but them inside\r
 204                 // byte_buf. From byte_buf the data is finally outputted to the stream.\r
 205                 void FlushBytes () \r
 206                 {\r
 207                         // write the encoding preamble only at the start of the stream\r
 208                         if (!preamble_done && byte_pos > 0) {\r
 209                                 byte[] preamble = internalEncoding.GetPreamble ();\r
 210                                 if (preamble.Length > 0)\r
 211                                         internalStream.Write (preamble, 0, preamble.Length);\r
 212                                 preamble_done = true;\r
 213                         }\r
 214                         internalStream.Write (byte_buf, 0, byte_pos);\r
 215                         byte_pos = 0;\r
 216                 }\r
 217                 \r
 218                 void Decode () \r
 219                 {\r
 220                         if (byte_pos > 0)\r
 221                                 FlushBytes ();\r
 222                         if (decode_pos > 0) {\r
 223                                 int len = internalEncoding.GetBytes (decode_buf, 0, decode_pos, byte_buf, byte_pos);\r
 224                                 byte_pos += len;\r
 225                                 decode_pos = 0;\r
 226                         }\r
 227                 }\r
 228                 \r
 229                 public override void Write (char[] buffer, int index, int count) \r
 230                 {\r
 231                         if (DisposedAlready)\r
 232                                 throw new ObjectDisposedException("StreamWriter");\r
 233                         if (buffer == null)\r
 234                                 throw new ArgumentNullException ("buffer");\r
 235                         if (index < 0)\r
 236                                 throw new ArgumentOutOfRangeException ("index", "< 0");\r
 237                         if (count < 0)\r
 238                                 throw new ArgumentOutOfRangeException ("count", "< 0");\r
 239                         // re-ordered to avoid possible integer overflow\r
 240                         if (index > buffer.Length - count)\r
 241                                 throw new ArgumentException ("index + count > buffer.Length");\r
 242 \r
 243                         LowLevelWrite (buffer, index, count);\r
 244                         if (iflush)\r
 245                                 Flush();\r
 246                 }\r
 247                 \r
 248                 void LowLevelWrite (char[] buffer, int index, int count)\r
 249                 {\r
 250                         while (count > 0) {\r
 251                                 int todo = decode_buf.Length - decode_pos;\r
 252                                 if (todo == 0) {\r
 253                                         Decode ();\r
 254                                         todo = decode_buf.Length;\r
 255                                 }\r
 256                                 if (todo > count)\r
 257                                         todo = count;\r
 258                                 Buffer.BlockCopy (buffer, index * 2, decode_buf, decode_pos * 2, todo * 2);\r
 259                                 count -= todo;\r
 260                                 index += todo;\r
 261                                 decode_pos += todo;\r
 262                         }\r
 263                 }\r
 264                 \r
 265                 void LowLevelWrite (string s)\r
 266                 {\r
 267                         int count = s.Length;\r
 268                         int index = 0;\r
 269                         while (count > 0) {\r
 270                                 int todo = decode_buf.Length - decode_pos;\r
 271                                 if (todo == 0) {\r
 272                                         Decode ();\r
 273                                         todo = decode_buf.Length;\r
 274                                 }\r
 275                                 if (todo > count)\r
 276                                         todo = count;\r
 277                                 \r
 278                                 for (int i = 0; i < todo; i ++)\r
 279                                         decode_buf [i + decode_pos] = s [i + index];\r
 280                                 \r
 281                                 count -= todo;\r
 282                                 index += todo;\r
 283                                 decode_pos += todo;\r
 284                         }\r
 285                 }\r
 286 \r
 287                 public override void Write (char value)\r
 288                 {\r
 289                         if (DisposedAlready)\r
 290                                 throw new ObjectDisposedException("StreamWriter");\r
 291 \r
 292                         // the size of decode_buf is always > 0 and\r
 293                         // we check for overflow right away\r
 294                         if (decode_pos >= decode_buf.Length)\r
 295                                 Decode ();\r
 296                         decode_buf [decode_pos++] = value;\r
 297                         if (iflush)\r
 298                                 Flush ();\r
 299                 }\r
 300 \r
 301                 public override void Write (char[] value)\r
 302                 {\r
 303                         if (DisposedAlready)\r
 304                                 throw new ObjectDisposedException("StreamWriter");\r
 305 \r
 306                         if (value != null)\r
 307                                 LowLevelWrite (value, 0, value.Length);\r
 308                         if (iflush)\r
 309                                 Flush ();\r
 310                 }\r
 311 \r
 312                 public override void Write (string value) \r
 313                 {\r
 314                         if (DisposedAlready)\r
 315                                 throw new ObjectDisposedException("StreamWriter");\r
 316 \r
 317                         if (value != null)\r
 318                                 LowLevelWrite (value);\r
 319                         \r
 320                         if (iflush)\r
 321                                 Flush ();\r
 322                 }\r
 323 \r
 324                 public override void Close()\r
 325                 {\r
 326                         closed = true;\r
 327                         Dispose (true);\r
 328                 }\r
 329 \r
 330                 ~StreamWriter ()\r
 331                 {\r
 332                         Dispose(false);\r
 333                 }\r
 334         }\r
 335 }\r