"""Read completed Single records once, without interfering with acquisition."""
class CaptureState:
    def __init__(self):
        self.armed = False
        self.delivered = None

    def arm(self):
        self.armed = True

    def ready(self, status):
        running, single, count = status
        if not single:
            self.armed = False
            self.delivered = None
            return running
        if running or count == 0:
            self.armed = True
            return False
        return count > 0 and (self.armed or self.delivered != count)

    def consumed(self, status):
        if status[1]:
            self.delivered = status[2]
            self.armed = False