class TaskJuggler::IntervalList

# File lib/taskjuggler/IntervalList.rb, line 24
def &(list)
  res = IntervalList.new
  si = li = 0
  while si < length && li < list.length do
    if self[si].start < list[li].start
      # The current Interval of self starts earlier than the current
      # Interval of list.
      if self[si].end <= list[li].start
        # self[si] does not overlap with list[li]. Ignore it.
        si += 1
      elsif self[si].end < list[li].end
        # self[si] does overlap with list[li] but list[li] goes further
        res << self[si].class.new(list[li].start, self[si].end)
        si += 1
      else
        # self[si] does overlap with list[li] but self[si] goes further
        res << self[si].class.new(list[li].start, list[li].end)
        li += 1
      end
    elsif list[li].start < self[si].start
      # The current Interval of list starts earlier than the current
      # Interval of self.
      if list[li].end <= self[si].start
        # list[li] does not overlap with self[si]. Ignore it.
        li += 1
      elsif list[li].end < self[si].end
        # list[li] does overlap with self[si] but self[si] goes further
        res << self[si].class.new(self[si].start, list[li].end)
        li += 1
      else
        # list[li] does overlap with self[si] but list[li] goes further
        res << self[si].class.new(self[si].start, self[si].end)
        si += 1
      end
    else
      # self[si].start and list[li].start are identical
      if self[si].end == list[li].end
        # self[si] and list[li] are identical. Add the Interval and
        # increase both pointers.
        res << self[si]
        li += 1
        si += 1
      elsif self[si].end < list[li].end
        # self[si] ends earlier.
        res << self[si]
        si += 1
      else
        # list[li] ends earlier.
        res << list[li]
        li += 1
      end
    end
  end

  res
end

# File lib/taskjuggler/IntervalList.rb, line 83
def <<(iv)
  if last
    if last.end > iv.start
      raise "Intervals may not overlap and must be added in " +
            "ascending order."
    elsif last.end == iv.start
      self[-1] = last.class.new(last.start, iv.end)
      return self
    end
  end

  append(iv)
end