package sshtun

type handshakePerLineReader struct {
	buf []byte
	off int
	cb  func(line string)
}

func newHandshakePerLineReader(cb func(string)) func([]byte) {
	if cb == nil {
		return nil
	}
	lr := &handshakePerLineReader{cb: cb, buf: make([]byte, 1024)}
	return lr.packet
}

func (h *handshakePerLineReader) packet(p []byte) {
	for _, char := range p {
		if (char == 10 || char == 13) && len(h.buf) > 0 {
			h.cb(string(h.buf[:h.off]))
			h.off = 0
		}
		if cap(h.buf) <= (h.off + 1) {
			newBuf := make([]byte, cap(h.buf)+256)
			copy(newBuf, h.buf)
			h.buf = newBuf
		}
		h.buf[h.off] = char
		h.off++
	}
}