* roottypes.cs: Rename from tree.cs.
[mono.git] / mcs / class / corlib / System.IO / StreamReader.cs
index 794e19b43a4aee75645811052f11ae278ed3b8ac..13246bf916dc624c3a04d9864209c47edd61393f 100644 (file)
-//\r
-// System.IO.StreamReader.cs\r
-//\r
-// Author:\r
-//   Dietmar Maurer (dietmar@ximian.com)\r
-//\r
-// (C) Ximian, Inc.  http://www.ximian.com\r
-//\r
-\r
-using System;\r
-using System.Text;\r
-\r
-namespace System.IO {\r
-       [Serializable]\r
-       public class StreamReader : TextReader {\r
-\r
-               private const int DefaultBufferSize = 1024;\r
-               private const int DefaultFileBufferSize = 4096;\r
-               private const int MinimumBufferSize = 128;\r
-\r
-               // buffering members\r
-               private byte [] rgbEncoded;\r
-//             private int cbEncoded;\r
-               private char [] rgchDecoded;\r
-               private int cchDecoded;\r
-\r
-               private int pos;\r
-\r
-\r
-               private Encoding internalEncoding;\r
-               private Decoder decoder;\r
-\r
-               private Stream internalStream;\r
-\r
-               [MonoTODO("Make Read methods return 0, etc.")]\r
-               private class NullStreamReader : StreamReader {\r
-               }\r
-\r
-               public new static readonly StreamReader Null = (StreamReader)(new NullStreamReader());\r
-\r
-               internal StreamReader() {}\r
-\r
-               public StreamReader(Stream stream)\r
-                       : this (stream, null, false, DefaultBufferSize) { }\r
-\r
-               public StreamReader(Stream stream, bool detectEncodingFromByteOrderMarks)\r
-                       : this (stream, null, detectEncodingFromByteOrderMarks, DefaultBufferSize) { }\r
-\r
-               public StreamReader(Stream stream, Encoding encoding)\r
-                       : this (stream, encoding, false, DefaultBufferSize) { }\r
-\r
-               public StreamReader(Stream stream, Encoding encoding, bool detectEncodingFromByteOrderMarks)\r
-                       : this (stream, encoding, detectEncodingFromByteOrderMarks, DefaultBufferSize) { }\r
-               \r
-               public StreamReader(Stream stream, Encoding encoding, bool detectEncodingFromByteOrderMarks, int bufferSize)\r
-               {\r
-                       Initialize (stream, encoding, detectEncodingFromByteOrderMarks, bufferSize);\r
-               }\r
-\r
-               public StreamReader(string path)\r
-                       : this (path, null, false, DefaultFileBufferSize) { }\r
-\r
-               public StreamReader(string path, bool detectEncodingFromByteOrderMarks)\r
-                       : this (path, null, detectEncodingFromByteOrderMarks, DefaultFileBufferSize) { }\r
-\r
-               public StreamReader(string path, Encoding encoding)\r
-                       : this (path, encoding, false, DefaultFileBufferSize) { }\r
-\r
-               public StreamReader(string path, Encoding encoding, bool detectEncodingFromByteOrderMarks)\r
-                       : this (path, encoding, detectEncodingFromByteOrderMarks, DefaultFileBufferSize) { }\r
-               \r
-               [MonoTODO]\r
-               public StreamReader(string path, Encoding encoding, bool detectEncodingFromByteOrderMarks, int bufferSize)\r
-               {\r
-                       if (null == path)\r
-                               throw new ArgumentNullException();\r
-                       if (String.Empty == path)\r
-                               throw new ArgumentException();\r
-                       if (path.IndexOfAny (Path.InvalidPathChars) != -1)\r
-                               throw new ArgumentException("path contains invalid characters");\r
-\r
-                       string DirName = Path.GetDirectoryName(path);\r
-                       if (DirName != String.Empty && !Directory.Exists(DirName))\r
-                               throw new DirectoryNotFoundException();\r
-                       if (!File.Exists(path))\r
-                               throw new FileNotFoundException(path);\r
-\r
-                       Stream stream = (Stream) File.OpenRead (path);\r
-                       Initialize (stream, encoding, detectEncodingFromByteOrderMarks, bufferSize);\r
-               }\r
-\r
-               [MonoTODO]\r
-               protected void Initialize (Stream stream, Encoding encoding, bool detectEncodingFromByteOrderMarks, int bufferSize)\r
-               {\r
-                       if (null == stream)\r
-                               throw new ArgumentNullException();\r
-                       if (!stream.CanRead)\r
-                               throw new ArgumentException("Cannot read stream");\r
-\r
-                       internalStream = stream;\r
-\r
-                       // use detect encoding flag\r
-                       if (encoding == null) {\r
-                               internalEncoding = Encoding.UTF8;\r
-                               decoder = Encoding.UTF8.GetDecoder ();\r
-                       } else {\r
-                               internalEncoding = encoding;\r
-                               decoder = encoding.GetDecoder ();\r
-                       }\r
-\r
-                       if (bufferSize < MinimumBufferSize)\r
-                               bufferSize = MinimumBufferSize;\r
-\r
-                       rgbEncoded = new byte [bufferSize];\r
-                       rgchDecoded = new char [internalEncoding.GetMaxCharCount (bufferSize)];\r
-                       pos = 0;\r
-                       cchDecoded = 0;\r
-               }\r
-\r
-               public virtual Stream BaseStream\r
-               {\r
-                       get {\r
-                               return internalStream;\r
-                       }\r
-               }\r
-\r
-               public virtual Encoding CurrentEncoding\r
-               {\r
-                       get {\r
-                               return internalEncoding;\r
-                       }\r
-               }\r
-\r
-               public override void Close ()\r
-               {\r
-                       Dispose (true);\r
-               }\r
-\r
-               public void DiscardBufferedData ()\r
-               {\r
-                       pos = 0;\r
-                       cchDecoded = 0;\r
-\r
-/* I'm sure there's no need to do all this\r
-                       if ((cchDecoded == null) || (pos == cchDecoded.Length))\r
-                               return;\r
-\r
-                       if (!internalStream.CanSeek)\r
-                               return;\r
-\r
-                       int seek_back = pos - cchDecoded.Length;\r
-                       internalStream.Seek (seek_back, SeekOrigin.Current);\r
-*/\r
-               }\r
-\r
-\r
-               // the buffer is empty, fill it again\r
-               [MonoTODO ("handle byte order marks here")]\r
-               private int ReadBuffer ()\r
-               {\r
-                       pos = 0;\r
-                       int cbEncoded = 0;\r
-                       cchDecoded = 0;\r
-                       do      // keep looping until the decoder gives us some chars\r
-                       {\r
-                               cbEncoded = internalStream.Read (rgbEncoded, 0, rgbEncoded.Length);\r
-                               // TODO: remove this line when iconv is fixed\r
-                               int bufcnt = decoder.GetCharCount (rgbEncoded, 0, cbEncoded);\r
-\r
-                               if (cbEncoded == 0)\r
-                                       return 0;\r
-                               // TODO: remove byte order marks here\r
-                               cchDecoded += decoder.GetChars (rgbEncoded, 0, cbEncoded, rgchDecoded, 0);\r
-                       } while (cchDecoded == 0);\r
-\r
-                       return cchDecoded;\r
-               }\r
-\r
-               public override int Peek ()\r
-               {\r
-                       if (!internalStream.CanSeek)\r
-                               return -1;\r
-\r
-                       if (pos >= cchDecoded && ReadBuffer () == 0)\r
-                               return -1;\r
-\r
-                       return rgchDecoded [pos];\r
-               }\r
-\r
-               public override int Read ()\r
-               {\r
-                       if (pos >= cchDecoded && ReadBuffer () == 0)\r
-                               return -1;\r
-\r
-                       return rgchDecoded [pos++];\r
-               }\r
-\r
-               public override int Read (char[] dest_buffer, int index, int count)\r
-               {\r
-                       if (dest_buffer == null)\r
-                               throw new ArgumentException ();\r
-\r
-                       if ((index < 0) || (count < 0))\r
-                               throw new ArgumentOutOfRangeException ();\r
-\r
-                       if (index + count > dest_buffer.Length)\r
-                               throw new ArgumentException ();\r
-\r
-                       int cchRead = 0;\r
-                       while (count > 0)\r
-                       {\r
-                               if (pos >= cchDecoded && ReadBuffer () == 0)\r
-                                       return cchRead > 0? cchRead: -1;\r
-\r
-                               int cch = Math.Min (cchDecoded - pos, count);\r
-                               Array.Copy (rgchDecoded, pos, dest_buffer, index, cch);\r
-                               pos += cch;\r
-                               index += cch;\r
-                               count -= cch;\r
-                               cchRead += cch;\r
-                       }\r
-                       return cchRead;\r
-               }\r
-\r
-               public override string ReadLine()\r
-               {\r
-                       StringBuilder text = new StringBuilder ();\r
-\r
-                       while (true) {\r
-                               int c = Read ();\r
-\r
-                               if (c == -1) {                          // end of stream\r
-                                       if (text.Length == 0)\r
-                                               return null;\r
-\r
-                                       break;\r
-                               }\r
-\r
-                               if (c == '\n') {                        // newline\r
-                                       if ((text.Length > 0) && (text [text.Length - 1] == '\r'))\r
-                                               text.Length--;\r
-                                       break;\r
-                               }\r
-\r
-                               text.Append ((char) c);\r
-                       }\r
-\r
-                       return text.ToString ();\r
-               }\r
-\r
-               public override string ReadToEnd()\r
-               {\r
-                       StringBuilder text = new StringBuilder ();\r
-\r
-                       int c;\r
-                       while ((c = Read ()) != -1) {\r
-                               text.Append ((char) c);\r
-                       }\r
-\r
-                       if (text.Length == 0)\r
-                               return String.Empty;\r
-                       return text.ToString ();\r
-               }\r
-       }\r
-}\r
+//
+// System.IO.StreamReader.cs
+//
+// Author:
+//   Dietmar Maurer (dietmar@ximian.com)
+//   Miguel de Icaza (miguel@ximian.com) 
+//
+// (C) Ximian, Inc.  http://www.ximian.com
+// Copyright (C) 2004 Novell (http://www.novell.com)
+//
+
+//
+// Copyright (C) 2004 Novell, Inc (http://www.novell.com)
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+// 
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+using System;
+using System.Text;
+using System.Runtime.InteropServices;
+
+namespace System.IO {
+       [Serializable]
+       public class StreamReader : TextReader {
+
+               const int DefaultBufferSize = 1024;
+               const int DefaultFileBufferSize = 4096;
+               const int MinimumBufferSize = 128;
+
+               //
+               // The input buffer
+               //
+               byte [] input_buffer;
+
+               //
+               // The decoded buffer from the above input buffer
+               //
+               char [] decoded_buffer;
+
+               //
+               // Decoded bytes in decoded_buffer.
+               //
+               int decoded_count;
+
+               //
+               // Current position in the decoded_buffer
+               //
+               int pos;
+
+               //
+               // The buffer size that we are using
+               //
+               int buffer_size;
+
+               int do_checks;
+               
+               Encoding encoding;
+               Decoder decoder;
+
+               Stream base_stream;
+               bool mayBlock;
+               StringBuilder line_builder;
+
+               private class NullStreamReader : StreamReader {
+                       public override int Peek ()
+                       {
+                               return -1;
+                       }
+
+                       public override int Read ()
+                       {
+                               return -1;
+                       }
+
+                       public override int Read ([In, Out] char[] buffer, int index, int count)
+                       {
+                               return 0;
+                       }
+
+                       public override string ReadLine ()
+                       {
+                               return null;
+                       }
+
+                       public override string ReadToEnd ()
+                       {
+                               return String.Empty;
+                       }
+
+                       public override Stream BaseStream
+                       {
+                               get { return Stream.Null; }
+                       }
+
+                       public override Encoding CurrentEncoding
+                       {
+                               get { return Encoding.Unicode; }
+                       }
+               }
+
+               public new static readonly StreamReader Null =  (StreamReader)(new NullStreamReader());
+               
+               internal StreamReader() {}
+
+               public StreamReader(Stream stream)
+                       : this (stream, Encoding.UTF8Unmarked, true, DefaultBufferSize) { }
+
+               public StreamReader(Stream stream, bool detect_encoding_from_bytemarks)
+                       : this (stream, Encoding.UTF8Unmarked, detect_encoding_from_bytemarks, DefaultBufferSize) { }
+
+               public StreamReader(Stream stream, Encoding encoding)
+                       : this (stream, encoding, true, DefaultBufferSize) { }
+
+               public StreamReader(Stream stream, Encoding encoding, bool detect_encoding_from_bytemarks)
+                       : this (stream, encoding, detect_encoding_from_bytemarks, DefaultBufferSize) { }
+               
+               public StreamReader(Stream stream, Encoding encoding, bool detect_encoding_from_bytemarks, int buffer_size)
+               {
+                       Initialize (stream, encoding, detect_encoding_from_bytemarks, buffer_size);
+               }
+
+               public StreamReader(string path)
+                       : this (path, Encoding.UTF8Unmarked, true, DefaultFileBufferSize) { }
+
+               public StreamReader(string path, bool detect_encoding_from_bytemarks)
+                       : this (path, Encoding.UTF8Unmarked, detect_encoding_from_bytemarks, DefaultFileBufferSize) { }
+
+               public StreamReader(string path, Encoding encoding)
+                       : this (path, encoding, true, DefaultFileBufferSize) { }
+
+               public StreamReader(string path, Encoding encoding, bool detect_encoding_from_bytemarks)
+                       : this (path, encoding, detect_encoding_from_bytemarks, DefaultFileBufferSize) { }
+               
+               public StreamReader(string path, Encoding encoding, bool detect_encoding_from_bytemarks, int buffer_size)
+               {
+                       if (null == path)
+                               throw new ArgumentNullException("path");
+                       if (String.Empty == path)
+                               throw new ArgumentException("Empty path not allowed");
+                       if (path.IndexOfAny (Path.InvalidPathChars) != -1)
+                               throw new ArgumentException("path contains invalid characters");
+                       if (null == encoding)
+                               throw new ArgumentNullException ("encoding");
+                       if (buffer_size <= 0)
+                               throw new ArgumentOutOfRangeException ("buffer_size", "The minimum size of the buffer must be positive");
+
+                       string DirName = Path.GetDirectoryName(path);
+                       if (DirName != String.Empty && !Directory.Exists(DirName))
+                               throw new DirectoryNotFoundException ("Directory '" + DirName + "' not found.");
+                       if (!File.Exists(path))
+                               throw new FileNotFoundException("File not found.", path);
+
+                       Stream stream = (Stream) File.OpenRead (path);
+                       Initialize (stream, encoding, detect_encoding_from_bytemarks, buffer_size);
+               }
+
+               internal void Initialize (Stream stream, Encoding encoding, bool detect_encoding_from_bytemarks, int buffer_size)
+               {
+                       if (null == stream)
+                               throw new ArgumentNullException ("stream");
+                       if (null == encoding)
+                               throw new ArgumentNullException ("encoding");
+                       if (!stream.CanRead)
+                               throw new ArgumentException ("Cannot read stream");
+                       if (buffer_size <= 0)
+                               throw new ArgumentOutOfRangeException ("buffer_size", "The minimum size of the buffer must be positive");
+
+                       if (buffer_size < MinimumBufferSize)
+                               buffer_size = MinimumBufferSize;
+
+                       base_stream = stream;
+                       input_buffer = new byte [buffer_size];
+                       this.buffer_size = buffer_size;
+                       this.encoding = encoding;
+                       decoder = encoding.GetDecoder ();
+
+                       byte [] preamble = encoding.GetPreamble ();
+                       do_checks = detect_encoding_from_bytemarks ? 1 : 0;
+                       do_checks += (preamble.Length == 0) ? 0 : 2;
+                       
+                       decoded_buffer = new char [encoding.GetMaxCharCount (buffer_size)];
+                       decoded_count = 0;
+                       pos = 0;
+               }
+
+               public virtual Stream BaseStream
+               {
+                       get {
+                               return base_stream;
+                       }
+               }
+
+               public virtual Encoding CurrentEncoding
+               {
+                       get {
+                               if (encoding == null)
+                                       throw new Exception ();
+                               return encoding;
+                       }
+               }
+
+#if NET_2_0
+               public bool EndOfStream {
+                       get { return Peek () < 0; }
+               }
+#endif
+
+               public override void Close ()
+               {
+                       Dispose (true);
+               }
+
+               protected override void Dispose (bool disposing)
+               {
+                       if (disposing && base_stream != null)
+                               base_stream.Close ();
+                       
+                       input_buffer = null;
+                       decoded_buffer = null;
+                       encoding = null;
+                       decoder = null;
+                       base_stream = null;
+                       base.Dispose (disposing);
+               }
+
+               //
+               // Provides auto-detection of the encoding, as well as skipping over
+               // byte marks at the beginning of a stream.
+               //
+               int DoChecks (int count)
+               {
+                       if ((do_checks & 2) == 2){
+                               byte [] preamble = encoding.GetPreamble ();
+                               int c = preamble.Length;
+                               if (count >= c){
+                                       int i;
+                                       
+                                       for (i = 0; i < c; i++)
+                                               if (input_buffer [i] != preamble [i])
+                                                       break;
+
+                                       if (i == c)
+                                               return i;
+                               }
+                       }
+
+                       if ((do_checks & 1) == 1){
+                               if (count < 2)
+                                       return 0;
+
+                               if (input_buffer [0] == 0xfe && input_buffer [1] == 0xff){
+                                       this.encoding = Encoding.BigEndianUnicode;
+                                       return 2;
+                               }
+
+                               if (input_buffer [0] == 0xff && input_buffer [1] == 0xfe){
+                                       this.encoding = Encoding.Unicode;
+                                       return 2;
+                               }
+
+                               if (count < 3)
+                                       return 0;
+
+                               if (input_buffer [0] == 0xef && input_buffer [1] == 0xbb && input_buffer [2] == 0xbf){
+                                       this.encoding = Encoding.UTF8Unmarked;
+                                       return 3;
+                               }
+                       }
+
+                       return 0;
+               }
+
+               public void DiscardBufferedData ()
+               {
+                       pos = decoded_count = 0;
+                       mayBlock = false;
+                       // Discard internal state of the decoder too.
+                       decoder = encoding.GetDecoder ();
+               }
+               
+               // the buffer is empty, fill it again
+               private int ReadBuffer ()
+               {
+                       pos = 0;
+                       int cbEncoded = 0;
+
+                       // keep looping until the decoder gives us some chars
+                       decoded_count = 0;
+                       int parse_start = 0;
+                       do      
+                       {
+                               cbEncoded = base_stream.Read (input_buffer, 0, buffer_size);
+                               
+                               if (cbEncoded == 0)
+                                       return 0;
+
+                               mayBlock = (cbEncoded < buffer_size);
+                               if (do_checks > 0){
+                                       Encoding old = encoding;
+                                       parse_start = DoChecks (cbEncoded);
+                                       if (old != encoding){
+                                               decoder = encoding.GetDecoder ();
+                                       }
+                                       do_checks = 0;
+                                       cbEncoded -= parse_start;
+                               }
+                               
+                               decoded_count += decoder.GetChars (input_buffer, parse_start, cbEncoded, decoded_buffer, 0);
+                               parse_start = 0;
+                       } while (decoded_count == 0);
+
+                       return decoded_count;
+               }
+
+               public override int Peek ()
+               {
+                       if (base_stream == null)
+                               throw new ObjectDisposedException ("StreamReader", "Cannot read from a closed StreamReader");
+                       if (pos >= decoded_count && (mayBlock || ReadBuffer () == 0))
+                               return -1;
+
+                       return decoded_buffer [pos];
+               }
+
+               public override int Read ()
+               {
+                       if (base_stream == null)
+                               throw new ObjectDisposedException ("StreamReader", "Cannot read from a closed StreamReader");
+                       if (pos >= decoded_count && ReadBuffer () == 0)
+                               return -1;
+
+                       return decoded_buffer [pos++];
+               }
+
+               public override int Read ([In, Out] char[] dest_buffer, int index, int count)
+               {
+                       if (base_stream == null)
+                               throw new ObjectDisposedException ("StreamReader", "Cannot read from a closed StreamReader");
+                       if (dest_buffer == null)
+                               throw new ArgumentNullException ("dest_buffer");
+                       if (index < 0)
+                               throw new ArgumentOutOfRangeException ("index", "< 0");
+                       if (count < 0)
+                               throw new ArgumentOutOfRangeException ("count", "< 0");
+                       // re-ordered to avoid possible integer overflow
+                       if (index > dest_buffer.Length - count)
+                               throw new ArgumentException ("index + count > dest_buffer.Length");
+
+                       int chars_read = 0;
+                       while (count > 0)
+                       {
+                               if (pos >= decoded_count && ReadBuffer () == 0)
+                                       return chars_read > 0 ? chars_read : 0;
+
+                               int cch = Math.Min (decoded_count - pos, count);
+                               Array.Copy (decoded_buffer, pos, dest_buffer, index, cch);
+                               pos += cch;
+                               index += cch;
+                               count -= cch;
+                               chars_read += cch;
+                       }
+                       return chars_read;
+               }
+
+               bool foundCR;
+               int FindNextEOL ()
+               {
+                       char c = '\0';
+                       for (; pos < decoded_count; pos++) {
+                               c = decoded_buffer [pos];
+                               if (c == '\n') {
+                                       pos++;
+                                       int res = (foundCR) ? (pos - 2) : (pos - 1);
+                                       if (res < 0)
+                                               res = 0; // if a new buffer starts with a \n and there was a \r at
+                                                       // the end of the previous one, we get here.
+                                       foundCR = false;
+                                       return res;
+                               } else if (foundCR) {
+                                       foundCR = false;
+                                       return pos - 1;
+                               }
+
+                               foundCR = (c == '\r');
+                       }
+
+                       return -1;
+               }
+
+               public override string ReadLine()
+               {
+                       if (base_stream == null)
+                               throw new ObjectDisposedException ("StreamReader", "Cannot read from a closed StreamReader");
+
+                       if (pos >= decoded_count && ReadBuffer () == 0)
+                               return null;
+
+                       int begin = pos;
+                       int end = FindNextEOL ();
+                       if (end < decoded_count && end >= begin)
+                               return new string (decoded_buffer, begin, end - begin);
+
+                       if (line_builder == null)
+                               line_builder = new StringBuilder ();
+                       else
+                               line_builder.Length = 0;
+
+                       while (true) {
+                               if (foundCR) // don't include the trailing CR if present
+                                       decoded_count--;
+
+                               line_builder.Append (decoded_buffer, begin, decoded_count - begin);
+                               if (ReadBuffer () == 0) {
+                                       if (line_builder.Capacity > 32768) {
+                                               StringBuilder sb = line_builder;
+                                               line_builder = null;
+                                               return sb.ToString (0, sb.Length);
+                                       }
+                                       return line_builder.ToString (0, line_builder.Length);
+                               }
+
+                               begin = pos;
+                               end = FindNextEOL ();
+                               if (end < decoded_count && end >= begin) {
+                                       line_builder.Append (decoded_buffer, begin, end - begin);
+                                       if (line_builder.Capacity > 32768) {
+                                               StringBuilder sb = line_builder;
+                                               line_builder = null;
+                                               return sb.ToString (0, sb.Length);
+                                       }
+                                       return line_builder.ToString (0, line_builder.Length);
+                               }
+                       }
+               }
+
+               public override string ReadToEnd()
+               {
+                       if (base_stream == null)
+                               throw new ObjectDisposedException ("StreamReader", "Cannot read from a closed StreamReader");
+
+                       StringBuilder text = new StringBuilder ();
+
+                       int size = decoded_buffer.Length;
+                       char [] buffer = new char [size];
+                       int len;
+                       
+                       while ((len = Read (buffer, 0, size)) > 0)
+                               text.Append (buffer, 0, len);
+
+                       return text.ToString ();
+               }
+       }
+}