mono/mcs/class/corlib/System.IO/TextReader.cs

//
// System.IO.TextReader
//
// Authors:
//   Marcin Szczepanski ([email protected])
//   Miguel de Icaza ([email protected])
//

//
// 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.Runtime.InteropServices;

namespace System.IO {

	[Serializable]
	[ComVisible (true)]
#if NET_2_1
	public abstract class TextReader : IDisposable {
#else
	public abstract class TextReader : MarshalByRefObject, IDisposable {
#endif
		static TextReader ()
		{
			Null = new NullTextReader ();
		}

		protected TextReader() { }
		
		public static readonly TextReader Null;
		
		public virtual void Close()
		{ 
			Dispose(true);
		}

		public void Dispose ()
		{
			Dispose(true);
		}

		protected virtual void Dispose (bool disposing)
		{
			if (disposing){
				// If we are explicitly disposed, we can avoid finalization.
				GC.SuppressFinalize (this);
			}
			return;
		}
		
		public virtual int Peek()
		{
			return -1;
		}
		
		public virtual int Read()
		{
			return -1;
		}
		

		public virtual int Read ([In, Out] char[] buffer, int index, int count)
		{
			int c, i;
			
			for (i = 0; i < count; i++) {
				if ((c = Read ()) == -1)
					return i;
				buffer [index + i] = (char)c;
			}
			
			return i;
		}
		
		public virtual int ReadBlock ([In, Out] char [] buffer, int index, int count)
		{
			int total_read_count = 0;
                        int current_read_count = 0;

			do {
				current_read_count = Read (buffer, index, count);
				index += current_read_count;
				total_read_count += current_read_count;
				count -= current_read_count;
			} while (current_read_count != 0 && count > 0);

			return total_read_count;
		}

		public virtual string ReadLine()
		{ 
			return String.Empty;
		}

		public virtual string ReadToEnd()
		{ 
			return String.Empty;
		}

		public static TextReader Synchronized (TextReader reader)
		{
			if (reader == null)
				throw new ArgumentNullException ("reader is null");
			if (reader is SynchronizedReader)
				return reader;

			return new SynchronizedReader (reader);
		}	

		private class NullTextReader : System.IO.TextReader {

			public override string ReadLine ()
			{
				return null;
			}
		}
	}

	//
	// Synchronized Reader implementation, used internally.
	//
	[Serializable]
	internal class SynchronizedReader : TextReader {
		TextReader reader;
		
		public SynchronizedReader (TextReader reader)
		{
			this.reader = reader;
		}

		public override void Close ()
		{
			lock (this){
				reader.Close ();
			}
		}

		public override int Peek ()
		{
			lock (this){
				return reader.Peek ();
			}
		}

		public override int ReadBlock (char [] buffer, int index, int count)
		{
			lock (this){
				return reader.ReadBlock (buffer, index, count);
			}
		}

		public override string ReadLine ()
		{
			lock (this){
				return reader.ReadLine ();
			}
		}

		public override string ReadToEnd ()
		{
			lock (this){
				return reader.ReadToEnd ();
			}
		}
#region Read Methods
		public override int Read ()
		{
			lock (this){
				return reader.Read ();
			}
		}

		public override int Read (char [] buffer, int index, int count)
		{
			lock (this){
				return reader.Read (buffer, index, count);
			}
		}
#endregion
		
	}
}