#--------------------------------------#
# Edgar Date conversions.              #
#--------------------------------------#
# These functions are copied from
# "Practical astronomy with your calculator"
# Peter Duffett-Smith
# Cambridge University Press
# Second Edition
#
# EDGAR Modification:  don't allow fractional answers, round and take integers.
#

package date;

# Convert date to julian day number.

sub main'dtoj
{
     ($d, $m, $y) = split('-', $_[0]);

     if ($m == 1 || $m == 2)
     {
          $y--;
          $m += 12;
     }

     if ($y > 1582 || ($y == 1582 && $m > 10) || ($y == 1582 && $m == 10 && $d > 15))

{
          $A = int $y / 100;
          $B = 2 - $A + int $A / 4;
     }

     $C = int 365.25 * $y;
     $D = int 30.6001 * ($m + 1);

     $B + $C + $D + $d + 1720994;  # Here, truncate the annoying 0.5 at end
}

# Convert julian day number to date.

sub main'jtod
{
     $_[0] += 0.5;
     $I = int $_[0];
     $F = $_[0] - $I;

     if ($I > 2299160)
     {
          $A = int (($I - 1867216.25) / 36524.25);
          $B = $I + 1 + $A - int $A / 4;
     }
     else
     {
          $B = $I;
     }

     $C = $B + 1524;
     $D = int (($C - 122.1) / 365.25);
     $E = int 365.25 * $D;
     $G = int (($C - $E) / 30.6001);

     $d = $C - $E + $F - int 30.6001 * $G;
        $d = int($d);  # EDGAR mod:  stop annoying fractional answers.
     $m = $G < 13.5 ? $G - 1 : $G - 13;
     $y = $m > 2.5 ? $D - 4716 : $D - 4715;

     "$d-$m-$y";
}

# Convert date to day of week (0 = Sun 6 = Sat).

sub main'd2w
{
     $A = (&main'dtoj($_[0]) + 1.5) / 7;
     $X = ($A - int $A) * 7;
     $Y = $X - int $X;

     if ($Y > .5)
     {
          $X = int $X + 1;
     }
     elsif ($X > 0)
     {
          $X = int $X;
     }

     $X;
}

1;