UnexceptionalStreamReader.cs :  » 2.6.4-mono-.net-core » System.IO » System » IO » C# / CSharp Open Source

//
// System.IO.UnexceptionalStreamReader.cs
//
// Authors:
//   Dietmar Maurer (dietmar@ximian.com)
//   Miguel de Icaza (miguel@ximian.com)
//   Dick Porter (dick@ximian.com)
//   Sebastien Pouliot  <sebastien@ximian.com>
//
// (C) Ximian, Inc.  http://www.ximian.com
// Copyright (C) 2004-2005 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.
//


// This is a wrapper around StreamReader used by System.Console that
// catches IOException so that graphical applications don't suddenly
// get IO errors when their terminal vanishes.  See
// UnexceptionalStreamWriter too.

using System.Text;
using System.Runtime.InteropServices;

namespace System.IO{
  internal class UnexceptionalStreamReader : StreamReader {

    private static bool[] newline = new bool [Environment.NewLine.Length];

    private static char newlineChar;

    static UnexceptionalStreamReader () {
      string n = Environment.NewLine;
      if (n.Length == 1)
        newlineChar = n [0];
    }

    public UnexceptionalStreamReader(Stream stream)
      : base (stream)
    {
    }

    public UnexceptionalStreamReader(Stream stream, bool detect_encoding_from_bytemarks)
      : base (stream, detect_encoding_from_bytemarks)
    {
    }

    public UnexceptionalStreamReader(Stream stream, Encoding encoding)
      : base (stream, encoding)
    {
    }

    public UnexceptionalStreamReader(Stream stream, Encoding encoding, bool detect_encoding_from_bytemarks)
      : base (stream, encoding, detect_encoding_from_bytemarks)
    {
    }
    
    public UnexceptionalStreamReader(Stream stream, Encoding encoding, bool detect_encoding_from_bytemarks, int buffer_size)
      : base (stream, encoding, detect_encoding_from_bytemarks, buffer_size)
    {
    }

    public UnexceptionalStreamReader(string path)
      : base (path)
    {
    }

    public UnexceptionalStreamReader(string path, bool detect_encoding_from_bytemarks)
      : base (path, detect_encoding_from_bytemarks)
    {
    }

    public UnexceptionalStreamReader(string path, Encoding encoding)
      : base (path, encoding)
    {
    }

    public UnexceptionalStreamReader(string path, Encoding encoding, bool detect_encoding_from_bytemarks)
      : base (path, encoding, detect_encoding_from_bytemarks)
    {
    }
    
    public UnexceptionalStreamReader(string path, Encoding encoding, bool detect_encoding_from_bytemarks, int buffer_size)
      : base (path, encoding, detect_encoding_from_bytemarks, buffer_size)
    {
    }

    public override int Peek ()
    {
      try {
        return(base.Peek ());
      } catch (IOException) {
      }

      return(-1);
    }

    public override int Read ()
    {
      try {
        return(base.Read ());
      } catch (IOException) {
      }

      return(-1);
    }

    public override int Read ([In, Out] char[] dest_buffer,
            int index, int count)
    {
      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");
      // ordered to avoid possible integer overflow
      if (index > dest_buffer.Length - count)
        throw new ArgumentException ("index + count > dest_buffer.Length");

      int chars_read = 0;
      char nl = newlineChar;
      try {
        while (count > 0) {
          int c = base.Read ();
          if (c < 0)
            break;
          chars_read++;
          count--;

          dest_buffer [index] = (char) c;
          // shortcut when a new line is only one character (e.g. Linux, Mac)
          if (nl != (char)0) {
            if ((char)c == nl)
              return chars_read;
          } else {
            if (CheckEOL ((char)c))
              return chars_read;
          }
          index ++;
        }
      } catch (IOException) {
      }
      
      return chars_read;
    }

    private bool CheckEOL (char current)
    {
      // general case for any length (e.g. Windows)
      for (int i=0; i < newline.Length; i++) {
        if (!newline [i]) {
          if (current == Environment.NewLine [i]) {
            newline [i] = true;
            return (i == newline.Length - 1);
          }
          break;
        }
      }
      for (int j=0; j < newline.Length; j++)
        newline [j] = false;
      return false;
    }

    public override string ReadLine()
    {
      try {
        return(base.ReadLine ());
      } catch (IOException) {
      }

      return(null);
    }

    public override string ReadToEnd()
    {
      try {
        return(base.ReadToEnd ());
      } catch (IOException) {
      }

      return(null);
    }
  }
}