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authorGuido van Rossum <guido@python.org>1990-10-13 19:23:40 (GMT)
committerGuido van Rossum <guido@python.org>1990-10-13 19:23:40 (GMT)
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+# module calendar
+
+##############################
+# Calendar support functions #
+##############################
+
+# This is based on UNIX ctime() et al. (also Standard C and POSIX)
+# Subtle but crucial differences:
+# - the order of the elements of a 'struct tm' differs, to ease sorting
+# - months numbers are 1-12, not 0-11; month arrays have a dummy element 0
+# - Monday is the first day of the week (numbered 0)
+
+# These are really parameters of the 'time' module:
+epoch = 1970 # Time began on January 1 of this year (00:00:00 UCT)
+day_0 = 3 # The epoch begins on a Thursday (Monday = 0)
+
+# 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)
+
+# 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)
+
+# Exception raised for bad input (with string parameter for details)
+error = 'calendar error'
+
+# Turn seconds since epoch into calendar time
+def gmtime(secs):
+ if secs < 0: raise error, 'negative input to gmtime()'
+ mins, secs = divmod(secs, 60)
+ hours, mins = divmod(mins, 60)
+ days, hours = divmod(hours, 24)
+ wday = (days + day_0) % 7
+ year = epoch
+ # XXX Most of the following loop can be replaced by one division
+ while 1:
+ yd = 365 + isleap(year)
+ if days < yd: break
+ days = days - yd
+ year = year + 1
+ yday = days
+ month = January
+ while 1:
+ md = mdays[month] + (month = February and isleap(year))
+ if days < md: break
+ days = days - md
+ month = month + 1
+ return year, month, days + 1, hours, mins, secs, yday, wday
+ # XXX Week number also?
+
+# 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
+
+# Inverse of gmtime():
+# Turn UCT calendar time (less yday, wday) into seconds since epoch
+def mktime(year, month, day, hours, mins, secs):
+ days = day - 1
+ for m in range(January, month): days = days + mdays[m]
+ if isleap(year) and month > February: days = days+1
+ days = days + (year-epoch)*365 + leapdays(epoch, year)
+ return ((days*24 + hours)*60 + mins)*60 + secs
+
+# Full and abbreviated names of weekdays
+day_name = ('Monday', 'Tuesday', 'Wednesday', 'Thursday')
+day_name = day_name + ('Friday', 'Saturday', 'Sunday')
+day_abbr = ('Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun')
+
+# Full and abbreviated of months (1-based arrays!!!)
+month_name = ('', 'January', 'February', 'March', 'April')
+month_name = month_name + ('May', 'June', 'July', 'August')
+month_name = month_name + ('September', 'October', 'November', 'December')
+month_abbr = (' ', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun')
+month_abbr = month_abbr + ('Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec')
+
+# Zero-fill string to two positions (helper for asctime())
+def dd(s):
+ while len(s) < 2: s = '0' + s
+ return s
+
+# Blank-fill string to two positions (helper for asctime())
+def zd(s):
+ while len(s) < 2: s = ' ' + s
+ return s
+
+# Turn calendar time as returned by gmtime() into a string
+# (the yday parameter is for compatibility with gmtime())
+def asctime(year, month, day, hours, mins, secs, yday, wday):
+ s = day_abbr[wday] + ' ' + month_abbr[month] + ' ' + zd(`day`)
+ s = s + ' ' + dd(`hours`) + ':' + dd(`mins`) + ':' + dd(`secs`)
+ return s + ' ' + `year`
+
+# Localization: Minutes West from Greenwich
+# timezone = -2*60 # Middle-European time with DST on
+timezone = 5*60 # EST (sigh -- THINK time() doesn't return UCT)
+
+# Local time ignores DST issues for now -- adjust 'timezone' to fake it
+def localtime(secs):
+ return gmtime(secs - timezone*60)
+
+# UNIX-style ctime (except it doesn't append '\n'!)
+def ctime(secs):
+ return asctime(localtime(secs))
+
+######################
+# Non-UNIX additions #
+######################
+
+# Calendar printing etc.
+
+# 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)
+ days = secs / (24*60*60)
+ return (days + day_0) % 7
+
+# Return weekday (0-6 ~ Mon-Sun) and number of days (28-31) for year, month
+def monthrange(year, month):
+ 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_abbr[month]
+ try:
+ return mc_cache[key]
+ except RuntimeError:
+ 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/2) + str + ' '*(n-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: print ' '*width,
+ else:
+ if width > 2: print ' '*(width-3),
+ if day < 10: print '',
+ print day,
+
+# Return a header for a week
+def weekheader(width):
+ str = ''
+ for i in range(7):
+ if str: str = str + ' '
+ str = str + day_abbr[i%7][:width]
+ return str
+
+# Print a month's calendar
+def prmonth(year, month):
+ print weekheader(3)
+ for week in monthcalendar(year, month):
+ prweek(week, 3)
+ print
+
+# Spacing between month columns
+spacing = ' '
+
+# 3-column formatting for year calendars
+def format3c(a, b, c):
+ print center(a, 20), spacing, center(b, 20), spacing, center(c, 20)
+
+# 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 ' '*20,
+ else:
+ prweek(cal[i], 2)
+ print spacing,
+ print