ln.types/io/LineWriter.cs

using System;
using System.IO;
using System.Text;

namespace ln.types.io
{
    public delegate void LineReceivedDelegate(object sender, string line);

    public class LineWriter : TextWriter
    {
        public event LineReceivedDelegate LineReceived;
        public override Encoding Encoding => Encoding.UTF8;

        private void FireLineReceived(string line) => LineReceived?.Invoke(this, line);

        char[] lineBuffer = new char[8192];
        int cursor = 0;

        String CurrentLineBuffer => new string(lineBuffer, 0, cursor);

        public LineWriter()
        {
        }

        public override void Write(char value)
        {
            lock (this)
            {
                if (value == '\n')
                {
                    FireLineReceived(CurrentLineBuffer);
                    cursor = 0;
                } else if (cursor < lineBuffer.Length)
                {
                    lineBuffer[cursor++] = value;
                }
            }
        }

        public override void WriteLine() => Write('\n');
        public override void WriteLine(string value)
        {
            lock (this)
            {
                if (cursor > 0)
                {
                    value = CurrentLineBuffer + value;
                    cursor = 0;
                }
                FireLineReceived(value);
            }
        }

    }
}