--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@time/datenum.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,41 @@
+% DATENUM Converts a time object into MATLAB serial date representation
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% DESCRIPTION: Converts a time object into MATLAB serial date number.  A serial
+% date number of 1 corresponds to Jan-01-0000.  The year 0000 is merely a
+% reference point and is not intended to be interpreted as a real year.
+% 
+% NOTE: time objects formatting routines use the timezone specified in the LTPDA
+% toolbox preferences, while MATLAB time routines always work in the local time
+% zone, as specified by the operating system.  This conversion routine is built
+% so that the time string representation obtained by time.format() and the one
+% obtained from datestr(datenum(time)) are equivalent:
+%
+%   >> t1 = time();
+%   >> datestr(datenum(t1)) === t1.format('dd-mmm-yyyy HH:MM:SS')
+%
+% However, except in the cases where the timezone is set to UTC in the LTPDA
+% toolbox preferences, this implies that:
+%
+%   >> datenum(time()) ~= now()
+%
+% VERSION: $Id: datenum.m,v 1.2 2010/07/29 18:07:55 nicolodi Exp $
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+function num = datenum(obj)
+  
+  % number of seconds since 1970-01-01 00:00:00.000 UTC
+  num = double(obj);
+  
+  % take care of timezone offset
+  num = num + time.timezone.getOffset(num * 1000)/1000;
+  
+  % divide by 60*60*24 to convert into days and add offset computed in local time
+  num = num / 86400 + datenummx(1970,01,01,00,00,00);
+
+  % NOTE: the MEX function datenummx() is used instead of the datenum() MATLAB
+  % function to save time of the expensive input arguments checks performed by
+  % the later
+
+end
+