## Copyright (C) 2004 Paul Kienzle
##
## This file is part of Octave.
##
## Octave is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2, or (at your option)
## any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING.  If not, write to the Free
## Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
## 02110-1301, USA.

## -*- texinfo -*-
## @deftypefn {Function File} {@var{e} =} eomday (@var{y}, @var{m})
## Return the last day of the month @var{m} for the year @var{y}.
## @seealso{datenum, datevec, weekday}
## @end deftypefn

## Author: pkienzle <pkienzle@users.sf.net>
## Created: 25 July 2004
## Adapted-By: William Poetra Yoga Hadisoeseno <williampoetra@gmail.com>

function e = eomday (y, m)

  if (nargin != 2)
    usage ("e = eomday (y, m)");
  endif

  eom = [31, 28, 31, 30 ,31, 30, 31, 31, 30, 31, 30, 31];
  e = eom(m);
  e += (m == 2) & (mod (y, 4) == 0 & (mod (y, 100) != 0 | mod (y, 400) == 0));

endfunction

# tests
%!assert(eomday([-4:4],2),[29,28,28,28,29,28,28,28,29])
%!assert(eomday([-901,901],2),[28,28])
%!assert(eomday([-100,100],2),[28,28])
%!assert(eomday([-900,900],2),[28,28])
%!assert(eomday([-400,400],2),[29,29])
%!assert(eomday([-800,800],2),[29,29])
%!assert(eomday(2001,1:12),[31,28,31,30,31,30,31,31,30,31,30,31])
%!assert(eomday(1:3,1:3),[31,28,31])
%!assert(eomday(1:2000,2)',datevec(datenum(1:2000,3,0))(:,3))
%!assert([1900:1999](find(eomday(1900:1999,2*ones(1,100))==29)),[1904,1908,1912,1916,1920,1924,1928,1932,1936,1940,1944,1948,1952,1956,1960,1964,1968,1972,1976,1980,1984,1988,1992,1996])
# demos
%!demo
%! y = 1900:1999;
%! e = eomday (y, 2 * ones (1, 100));
%! y (find (e == 29))