C# StreamReader, “ReadLine” For Custom Delimiters

Question

What is the best way to have the functionality of the StreamReader.ReadLine() method, but with custom (String) delimiters?

I\'d like to do something like:

Answer 1

This code should work for any string separator.

public static IEnumerable ReadChunks(this TextReader reader, string chunkSep)
{
    var sb = new StringBuilder();

    var sepbuffer = new Queue(chunkSep.Length);
    var sepArray = chunkSep.ToCharArray();

    while (reader.Peek() >= 0)
    {
        var nextChar = (char)reader.Read();
        if (nextChar == chunkSep[sepbuffer.Count])
        {
            sepbuffer.Enqueue(nextChar);
            if (sepbuffer.Count == chunkSep.Length)
            {
                yield return sb.ToString();
                sb.Length = 0;
                sepbuffer.Clear();
            }
        }
        else
        {
            sepbuffer.Enqueue(nextChar);
            while (sepbuffer.Count > 0)
            {
                sb.Append(sepbuffer.Dequeue());
                if (sepbuffer.SequenceEqual(chunkSep.Take(sepbuffer.Count)))
                    break;
            }
        }
    }
    yield return sb.ToString() + new string(sepbuffer.ToArray());
}

Disclaimer:

I made a little testing on this and is actually slower than ReadLine method, but I suspect it is due to the enqueue/dequeue/sequenceEqual calls that in the ReadLine method can be avoided (because the separator is always \r\n).

Again, I made few tests and it should work, but don't take it as perfect, and feel free to correct it. ;)