Binary Parsing - Null Terminated ASCII with Max bytes

[benjamin-hodgson]

Binary Parsing - Null Terminated ASCII with Max bytes

[benjamin-hodgson]

I don't think there's a combinator which'll do this for-break type of loop out of the box. You can code it up yourself using recursion:

Parser<byte, IEnumerable<byte>> NullTerminated()
    => NullTerminated(64);

Parser<byte, IEnumerable<byte>> NullTerminated(int count)
{
    if (count == 0)
    {
        return Return(new[] { });
    }
    return Byte.Then(b =>
        b == 0
            ? Return(new[] { })
            : NullTerminated(count - 1).Select(bs => new[]{ b }.Concat(bs))
    );
}

ofc that won't be very efficient cos you're building parsers at runtime and storing the output bytes in a linked list shaped structure. (Could perhaps tweak this by eg putting the bytes in a List or caching the recursive NullTerminated calls but that's messy.)

---

One way to design an API for this might be some sort of "bounded Many", which runs a parser in a loop until it fails without consuming input or some maximum number of repetitions is reached. Then your code would look like this:

Parser<byte, IEnumerable<byte>> NullTerminated
    => Token(b => b != 0).ManyUpTo(64);  // name TBD

I'd be happy to accept a PR implementing this ManyUpTo combinator.