Lib/calendar.py

   1 ###############################
   2 # Calendar printing functions #
   3 ###############################
   4
   5 # Revision 2: uses funtions from built-in time module
   6
   7 # Import functions and variables from time module
   8 from time import gmtime, localtime, mktime, asctime, ctime
   9
  10 # Exception raised for bad input (with string parameter for details)
  11 error = 'calendar.error'
  12
  13 # Note when comparing these calendars to the ones printed by cal(1):
  14 # My calendars have Monday as the first day of the week, and Sunday as
  15 # the last!  (I believe this is the European convention.)
  16
  17 # Constants for months referenced later
  18 January = 1
  19 February = 2
  20
  21 # Number of days per month (except for February in leap years)
  22 mdays = [0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
  23
  24 # Full and abbreviated names of weekdays
  25 day_name = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', \
  26             'Friday', 'Saturday', 'Sunday']
  27 day_abbr = ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun']
  28
  29 # Full and abbreviated names of months (1-based arrays!!!)
  30 month_name =          ['', 'January',   'February', 'March',    'April', \
  31                            'May',       'June',     'July',     'August', \
  32                            'September', 'October',  'November', 'December']
  33 month_abbr =       ['   ', 'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', \
  34                            'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
  35
  36 # Return 1 for leap years, 0 for non-leap years
  37 def isleap(year):
  38         return year % 4 == 0 and (year % 100 <> 0 or year % 400 == 0)
  39
  40 # Return number of leap years in range [y1, y2)
  41 # Assume y1 <= y2 and no funny (non-leap century) years
  42 def leapdays(y1, y2):
  43         return (y2+3)/4 - (y1+3)/4
  44
  45 # Return weekday (0-6 ~ Mon-Sun) for year (1970-...), month (1-12), day (1-31)
  46 def weekday(year, month, day):
  47         secs = mktime((year, month, day, 0, 0, 0, 0, 0, 0))
  48         tuple = localtime(secs)
  49         return tuple[6]
  50
  51 # Return weekday (0-6 ~ Mon-Sun) and number of days (28-31) for year, month
  52 def monthrange(year, month):
  53         if not 1 <= month <= 12: raise ValueError, 'bad month number'
  54         day1 = weekday(year, month, 1)
  55         ndays = mdays[month] + (month == February and isleap(year))
  56         return day1, ndays
  57
  58 # Return a matrix representing a month's calendar
  59 # Each row represents a week; days outside this month are zero
  60 def _monthcalendar(year, month):
  61         day1, ndays = monthrange(year, month)
  62         rows = []
  63         r7 = range(7)
  64         day = 1 - day1
  65         while day <= ndays:
  66                 row = [0, 0, 0, 0, 0, 0, 0]
  67                 for i in r7:
  68                         if 1 <= day <= ndays: row[i] = day
  69                         day = day + 1
  70                 rows.append(row)
  71         return rows
  72
  73 # Caching interface to _monthcalendar
  74 _mc_cache = {}
  75 def monthcalendar(year, month):
  76         key = (year, month)
  77         if _mc_cache.has_key(key):
  78                 return _mc_cache[key]
  79         else:
  80                 _mc_cache[key] = ret = _monthcalendar(year, month)
  81                 return ret
  82
  83 # Center a string in a field
  84 def _center(str, width):
  85         n = width - len(str)
  86         if n <= 0: return str
  87         return ' '*((n+1)/2) + str + ' '*((n)/2)
  88
  89 # XXX The following code knows that print separates items with space!
  90
  91 # Print a single week (no newline)
  92 def prweek(week, width):
  93         for day in week:
  94                 if day == 0: s = ''
  95                 else: s = `day`
  96                 print _center(s, width),
  97
  98 # Return a header for a week
  99 def weekheader(width):
 100         str = ''
 101         if width >= 9: names = day_name
 102         else: names = day_abbr
 103         for i in range(7):
 104                 if str: str = str + ' '
 105                 str = str + _center(names[i%7][:width], width)
 106         return str
 107
 108 # Print a month's calendar
 109 def prmonth(year, month, w = 0, l = 0):
 110         w = max(2, w)
 111         l = max(1, l)
 112         print _center(month_name[month] + ' ' + `year`, 7*(w+1) - 1),
 113         print '\n'*l,
 114         print weekheader(w),
 115         print '\n'*l,
 116         for week in monthcalendar(year, month):
 117                 prweek(week, w)
 118                 print '\n'*l,
 119
 120 # Spacing of month columns
 121 _colwidth = 7*3 - 1                     # Amount printed by prweek()
 122 _spacing = ' '*4                        # Spaces between columns
 123
 124 # 3-column formatting for year calendars
 125 def format3c(a, b, c):
 126         print _center(a, _colwidth),
 127         print _spacing,
 128         print _center(b, _colwidth),
 129         print _spacing,
 130         print _center(c, _colwidth)
 131
 132 # Print a year's calendar
 133 def prcal(year):
 134         header = weekheader(2)
 135         format3c('', `year`, '')
 136         for q in range(January, January+12, 3):
 137                 print
 138                 format3c(month_name[q], month_name[q+1], month_name[q+2])
 139                 format3c(header, header, header)
 140                 data = []
 141                 height = 0
 142                 for month in range(q, q+3):
 143                         cal = monthcalendar(year, month)
 144                         if len(cal) > height: height = len(cal)
 145                         data.append(cal)
 146                 for i in range(height):
 147                         for cal in data:
 148                                 if i >= len(cal):
 149                                         print ' '*_colwidth,
 150                                 else:
 151                                         prweek(cal[i], 2)
 152                                 print _spacing,
 153                         print