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