def _version_compare_split_comp(comp_a, comp_b, conv):
    """
    Compare a single component of split version numbers.
    """
    if comp_a != '':
        if comp_b != '':
            if conv(comp_a) < conv(comp_b):
                return -1
            if conv(comp_a) > conv(comp_b):
                return 1
        else:
            return 1
    elif comp_b != '':
        return -1
    return None
