gramps/src/Julian.py
Don Allingham 1e1ef8dc73 Calendar updates
svn: r1247
2003-01-09 04:41:08 +00:00

120 lines
3.5 KiB
Python

#
# Gramps - a GTK+/GNOME based genealogy program
#
# Copyright (C) 2001 Donald N. Allingham
#
# This program 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 of the License, or
# (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
"""
Gregorian calendar module for GRAMPS.
The original algorithms for this module came from Scott E. Lee's
C implementation. The original C source can be found at Scott's
web site at http://www.scottlee.com
"""
__author__ = "Donald N. Allingham"
__version__ = "$Revision$"
#-------------------------------------------------------------------------
#
# Gramps Modules
#
#-------------------------------------------------------------------------
import Calendar
from intl import gettext as _
#-------------------------------------------------------------------------
#
# Julian
#
#-------------------------------------------------------------------------
class Julian(Calendar.Calendar):
"""Julian calendar"""
SDN_OFFSET = 32083
DAYS_PER_5_MONTHS = 153
DAYS_PER_4_YEARS = 1461
NAME = "Julian"
TNAME = _("Julian")
def quote_display(self,year,month,day,mode):
return "%s (%s)" % (self.display(year,month,day,mode),Julian.NAME)
def mlen(self):
return 3
def get_ymd(self,sdn):
"""Converts an SDN number to a Julian date"""
if sdn <= 0 :
return (0,0,0)
temp = (sdn + Julian.SDN_OFFSET) * 4 - 1
# Calculate the year and day of year (1 <= dayOfYear <= 366)
year = temp / Julian.DAYS_PER_4_YEARS
dayOfYear = (temp % Julian.DAYS_PER_4_YEARS) / 4 + 1
# Calculate the month and day of month
temp = dayOfYear * 5 - 3;
month = temp / Julian.DAYS_PER_5_MONTHS;
day = (temp % Julian.DAYS_PER_5_MONTHS) / 5 + 1;
# Convert to the normal beginning of the year
if month < 10:
month = month + 3
else:
year = year + 1
month = month - 9
# Adjust to the B.C./A.D. type numbering
year = year - 4800
if year <= 0:
year = year - 1
return (year,month,day)
def get_sdn(self,iyear,imonth,iday):
"""Converts a Julian calendar date to an SDN number"""
# check for invalid dates
if iyear==0 or iyear<-4713 or imonth<=0 or imonth>12 or iday<=0 or iday>31:
return 0
# check for dates before SDN 1 (Jan 2, 4713 B.C.)
if iyear == -4713:
if imonth == 1 and iday == 1:
return 0
# Make year always a positive number
if iyear < 0:
year = iyear + 4801
else:
year = iyear + 4800
# Adjust the start of the year
if imonth > 2:
month = imonth - 3
else:
month = imonth + 9
year = year - 1
return (year*Julian.DAYS_PER_4_YEARS)/4 + \
(month*Julian.DAYS_PER_5_MONTHS+2)/5 + \
iday - Julian.SDN_OFFSET
Calendar.register(Julian)