added createDateTimeFromMillis method: Returns a DateTime object, build from

the number of milliseconds since epoch.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@16080 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/DateUtils.py

@@ -362,3 +362,29 @@ def convertDateToHour(date=None):
   ordinal_reference_date = datetime.toordinal(reference_date)
   hour = (ordinal_date - ordinal_reference_date) * number_of_hours_in_day + number_of_hours_in_day + date.hour()
   return int(hour)
+
+def createDateTimeFromMillis(millis):
+  """
+  Returns a DateTime object, build from the number of milliseconds since epoch.
+  Parameter should be a int or long.
+
+  This one should be used by solvers, as DateTime.__cmp__ actually only
+  compares the _millis parameter of the two DateTime objects.
+
+  This is currently not perfect: DateTime only supports creating a new object
+  from a floating point number of seconds since epoch, so a rounding issue is
+  still possible, that's why _millis is explicitely set to the same value
+  after the DateTime object has been created from (millis / 1000.)
+
+  A better way would be to compute (yr,mo,dy,hr,mn,sc,tz,t,d,s,millisecs) from
+  millis, and then create the DateTime object from it (see "elif ac == 11:" in
+  DateTime._parse_args).
+
+  Another solution would be a DateTime implementation that relies exclusively
+  on integer values internally.
+  """
+  millis = long(millis)
+  date = DateTime(millis / 1000.)
+  date._millis = millis
+  return date
+