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

   1 //
   2 // System.IO.UnexceptionalStreamReader.cs
   3 //
   4 // Authors:
   5 //   Dietmar Maurer (dietmar@ximian.com)
   6 //   Miguel de Icaza (miguel@ximian.com)
   7 //   Dick Porter (dick@ximian.com)
   8 //   Sebastien Pouliot  <sebastien@ximian.com>
   9 //
  10 // (C) Ximian, Inc.  http://www.ximian.com
  11 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33
  34 // This is a wrapper around StreamReader used by System.Console that
  35 // catches IOException so that graphical applications don't suddenly
  36 // get IO errors when their terminal vanishes.  See
  37 // UnexceptionalStreamWriter too.
  38
  39 using System.Text;
  40 using System.Runtime.InteropServices;
  41
  42 namespace System.IO {
  43         internal class UnexceptionalStreamReader : StreamReader {
  44
  45                 private bool[] newline = new bool [Environment.NewLine.Length];
  46
  47                 public UnexceptionalStreamReader(Stream stream)
  48                         : base (stream)
  49                 {
  50                 }
  51
  52                 public UnexceptionalStreamReader(Stream stream, bool detect_encoding_from_bytemarks)
  53                         : base (stream, detect_encoding_from_bytemarks)
  54                 {
  55                 }
  56
  57                 public UnexceptionalStreamReader(Stream stream, Encoding encoding)
  58                         : base (stream, encoding)
  59                 {
  60                 }
  61
  62                 public UnexceptionalStreamReader(Stream stream, Encoding encoding, bool detect_encoding_from_bytemarks)
  63                         : base (stream, encoding, detect_encoding_from_bytemarks)
  64                 {
  65                 }
  66
  67                 public UnexceptionalStreamReader(Stream stream, Encoding encoding, bool detect_encoding_from_bytemarks, int buffer_size)
  68                         : base (stream, encoding, detect_encoding_from_bytemarks, buffer_size)
  69                 {
  70                 }
  71
  72                 public UnexceptionalStreamReader(string path)
  73                         : base (path)
  74                 {
  75                 }
  76
  77                 public UnexceptionalStreamReader(string path, bool detect_encoding_from_bytemarks)
  78                         : base (path, detect_encoding_from_bytemarks)
  79                 {
  80                 }
  81
  82                 public UnexceptionalStreamReader(string path, Encoding encoding)
  83                         : base (path, encoding)
  84                 {
  85                 }
  86
  87                 public UnexceptionalStreamReader(string path, Encoding encoding, bool detect_encoding_from_bytemarks)
  88                         : base (path, encoding, detect_encoding_from_bytemarks)
  89                 {
  90                 }
  91
  92                 public UnexceptionalStreamReader(string path, Encoding encoding, bool detect_encoding_from_bytemarks, int buffer_size)
  93                         : base (path, encoding, detect_encoding_from_bytemarks, buffer_size)
  94                 {
  95                 }
  96
  97                 public override int Peek ()
  98                 {
  99                         try {
 100                                 return(base.Peek ());
 101                         } catch (IOException) {
 102                         }
 103
 104                         return(-1);
 105                 }
 106
 107                 public override int Read ()
 108                 {
 109                         try {
 110                                 return(base.Read ());
 111                         } catch (IOException) {
 112                         }
 113
 114                         return(-1);
 115                 }
 116
 117                 public override int Read ([In, Out] char[] dest_buffer,
 118                                           int index, int count)
 119                 {
 120                         if (dest_buffer == null)
 121                                 throw new ArgumentNullException ("dest_buffer");
 122                         if (index < 0)
 123                                 throw new ArgumentOutOfRangeException ("index", "< 0");
 124                         if (count < 0)
 125                                 throw new ArgumentOutOfRangeException ("count", "< 0");
 126                         // ordered to avoid possible integer overflow
 127                         if (index > dest_buffer.Length - count)
 128                                 throw new ArgumentException ("index + count > dest_buffer.Length");
 129
 130                         int chars_read = 0;
 131                         while (count > 0) {
 132                                 int c = Read ();
 133                                 if (c < 0)
 134                                         break;
 135                                 chars_read++;
 136                                 count--;
 137
 138                                 dest_buffer [index] = (char) c;
 139                                 if (CheckEOL (dest_buffer [index++]))
 140                                         return chars_read;
 141                         }
 142                         return chars_read;
 143                 }
 144
 145                 private bool CheckEOL (char current)
 146                 {
 147                         // shortcut when a new line is only one character (e.g. Linux, Mac)
 148                         if (newline.Length == 1)
 149                                 return (current == Environment.NewLine [0]);
 150
 151                         // general case for any length (e.g. Windows)
 152                         for (int i=0; i < newline.Length; i++) {
 153                                 if (!newline [i]) {
 154                                         if (current == Environment.NewLine [i]) {
 155                                                 newline [i] = true;
 156                                                 return (i == newline.Length - 1);
 157                                         }
 158                                         break;
 159                                 }
 160                         }
 161                         for (int j=0; j < newline.Length; j++)
 162                                 newline [j] = false;
 163                         return false;
 164                 }
 165
 166                 public override string ReadLine()
 167                 {
 168                         try {
 169                                 return(base.ReadLine ());
 170                         } catch (IOException) {
 171                         }
 172
 173                         return(null);
 174                 }
 175
 176                 public override string ReadToEnd()
 177                 {
 178                         try {
 179                                 return(base.ReadToEnd ());
 180                         } catch (IOException) {
 181                         }
 182
 183                         return(null);
 184                 }
 185         }
 186 }