enum {
    DAY_MON = 0x01,
    DAY_TUE = 0x02,
    DAY_WED = 0x04,
    DAY_THU = 0x08,
    DAY_FRI = 0x10,
    DAY_SAT = 0x20,
    DAY_SUN = 0x40,

    MASK_WEEKEND = DAY_SAT|DAY_SUN,
    MASK_WORKDAYS = DAY_MON|DAY_TUE|DAY_WED|DAY_THU|DAY_FRI,
    MASK_EVERYDAY = DAY_MON|DAY_TUE|DAY_WED|DAY_THU|DAY_FRI|DAY_SAT|DAY_SUN
};