class FlightLogReader

  FLIGHT_LOG_LABELS = [
      :Time,           # GPS時刻(秒)
      :Longitude,
      :Latitude,
      :Altitude,
      :VNorth,
      :VEast,
      :VDown,
      :Yaw,
      :Pitch,
      :Roll,
      :Azimuth,
      :TAS,
      :AoAttack,
      :SideSlip,
      :Input,
      :Output,
      :AccX,          # 加速度(m/s^2) x軸(前)
      :AccY,          #               y軸(右)
      :AccZ,          #               z軸(下)
      :RollRate,
      :PitchRate,
      :YawRate,
      :RollAccel,
      :PitchAccel,
      :YawAccel
    ]
  
  def FlightLogReader.read(input, denom = 10)
    data = []
    line_no = 0
    
    op = proc{|io|
      io.each{|line|
        temp = line.chop.split(/,/)
        if temp.size >= FLIGHT_LOG_LABELS::size then
          line_no += 1
          if line_no % denom != 0 then  next end # データを間引く
          temp.collect!{|item| item.to_f}
          from_index = 0
          to_index = FLIGHT_LOG_LABELS.index(:Input)
          temp2 = temp[from_index...to_index]
          from_index = to_index
          to_index = to_index + 8
          temp2 << temp[from_index...to_index]
          from_index = to_index
          to_index = to_index + 8
          temp2 << temp[from_index...to_index]
          from_index = to_index
          temp2.push(*temp[from_index..-1])
          if block_given? then
            next unless (temp2 = yield temp2)
          end
          data << temp2
      end
      }
    }
    
    if input.kind_of?(String) # ファイル
      open(input){|fin|
        op.call(fin)
      }
    else
      op.call(input) # ストリーム
    end
    
    return data
  end
end