Days_Before : constant
  array (Is_Leap_Year, Month_Number)
  of Ada.Calendar.Arithmetic.Day_Count :=
  (False => (0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334),
   True  => (0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335));

Month_Length : constant
  array (Is_Leap_Year, Month_Number)
  of Ada.Calendar.Arithmetic.Day_Count :=
  (False => (31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31),
   True  => (31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31));

subtype Is_Leap_Year is
   Boolean;

subtype Day_Number_In_Era is
  Arithmetic.Day_Count range 1 .. Arithmetic.Day_Count'Last;

function Is_A_Leap_Year (Year : Integer)
                         return Boolean;

function Julian_Day (T : Time)
                     return Day_Number_In_Era;

function Julian_Day (Year  : Year_Number;
                     Month : Month_Number;
                     Day   : Day_Number)
                     return Integer;