cpython/Lib/calendar.py
1999-06-09 15:07:38 +00:00

171 lines
4.8 KiB
Python

###############################
# Calendar printing functions #
###############################
# Revision 2: uses funtions from built-in time module
# Import functions and variables from time module
from time import localtime, mktime
# Exception raised for bad input (with string parameter for details)
error = ValueError
# Note when comparing these calendars to the ones printed by cal(1):
# My calendars have Monday as the first day of the week, and Sunday as
# the last! (I believe this is the European convention.)
# Constants for months referenced later
January = 1
February = 2
# Number of days per month (except for February in leap years)
mdays = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
# Full and abbreviated names of weekdays
day_name = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', \
'Friday', 'Saturday', 'Sunday']
day_abbr = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
# Full and abbreviated names of months (1-based arrays!!!)
month_name = ['', 'January', 'February', 'March', 'April', \
'May', 'June', 'July', 'August', \
'September', 'October', 'November', 'December']
month_abbr = [' ', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', \
'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
# Return 1 for leap years, 0 for non-leap years
def isleap(year):
return year % 4 == 0 and (year % 100 <> 0 or year % 400 == 0)
# Return number of leap years in range [y1, y2)
# Assume y1 <= y2 and no funny (non-leap century) years
def leapdays(y1, y2):
return (y2+3)/4 - (y1+3)/4
# Return weekday (0-6 ~ Mon-Sun) for year (1970-...), month (1-12), day (1-31)
def weekday(year, month, day):
secs = mktime((year, month, day, 0, 0, 0, 0, 0, 0))
tuple = localtime(secs)
return tuple[6]
# Return weekday (0-6 ~ Mon-Sun) and number of days (28-31) for year, month
def monthrange(year, month):
if not 1 <= month <= 12: raise ValueError, 'bad month number'
day1 = weekday(year, month, 1)
ndays = mdays[month] + (month == February and isleap(year))
return day1, ndays
# Return a matrix representing a month's calendar
# Each row represents a week; days outside this month are zero
def _monthcalendar(year, month):
day1, ndays = monthrange(year, month)
rows = []
r7 = range(7)
day = 1 - day1
while day <= ndays:
row = [0, 0, 0, 0, 0, 0, 0]
for i in r7:
if 1 <= day <= ndays: row[i] = day
day = day + 1
rows.append(row)
return rows
# Caching interface to _monthcalendar
_mc_cache = {}
def monthcalendar(year, month):
key = (year, month)
if _mc_cache.has_key(key):
return _mc_cache[key]
else:
_mc_cache[key] = ret = _monthcalendar(year, month)
return ret
# Center a string in a field
def _center(str, width):
n = width - len(str)
if n <= 0: return str
return ' '*((n+1)/2) + str + ' '*((n)/2)
# XXX The following code knows that print separates items with space!
# Print a single week (no newline)
def prweek(week, width):
for day in week:
if day == 0: s = ''
else: s = `day`
print _center(s, width),
# Return a header for a week
def weekheader(width):
str = ''
if width >= 9: names = day_name
else: names = day_abbr
for i in range(7):
if str: str = str + ' '
str = str + _center(names[i%7][:width], width)
return str
# Print a month's calendar
def prmonth(year, month, w = 0, l = 0):
w = max(2, w)
l = max(1, l)
print _center(month_name[month] + ' ' + `year`, 7*(w+1) - 1),
print '\n'*l,
print weekheader(w),
print '\n'*l,
for week in monthcalendar(year, month):
prweek(week, w)
print '\n'*l,
# Spacing of month columns
_colwidth = 7*3 - 1 # Amount printed by prweek()
_spacing = ' '*4 # Spaces between columns
# 3-column formatting for year calendars
def format3c(a, b, c):
print _center(a, _colwidth),
print _spacing,
print _center(b, _colwidth),
print _spacing,
print _center(c, _colwidth)
# Print a year's calendar
def prcal(year):
header = weekheader(2)
format3c('', `year`, '')
for q in range(January, January+12, 3):
print
format3c(month_name[q], month_name[q+1], month_name[q+2])
format3c(header, header, header)
data = []
height = 0
for month in range(q, q+3):
cal = monthcalendar(year, month)
if len(cal) > height: height = len(cal)
data.append(cal)
for i in range(height):
for cal in data:
if i >= len(cal):
print ' '*_colwidth,
else:
prweek(cal[i], 2)
print _spacing,
print
# Unrelated but handy function to calculate Unix timestamp from GMT
EPOCH = 1970
def timegm(tuple):
year, month, day, hour, minute, second = tuple[:6]
assert year >= EPOCH
assert 1 <= month <= 12
days = 365*(year-EPOCH) + leapdays(EPOCH, year)
for i in range(1, month):
days = days + mdays[i]
if month > 2 and isleap(year):
days = days + 1
days = days + day - 1
hours = days*24 + hour
minutes = hours*60 + minute
seconds = minutes*60 + second
return seconds