diff options
Diffstat (limited to 'Lib/calendar.py')
| -rw-r--r-- | Lib/calendar.py | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/Lib/calendar.py b/Lib/calendar.py new file mode 100644 index 0000000..49e8e63 --- /dev/null +++ b/Lib/calendar.py @@ -0,0 +1,213 @@ +# 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 |