Lib/tzparse.py

   1 # Parse a timezone specification.
   2 # XXX Unfinished.
   3 # XXX Only the typical form "XXXhhYYY;ddd/hh,ddd/hh" is currently supported.
   4
   5 tzpat = ('^([A-Z][A-Z][A-Z])([-+]?[0-9]+)([A-Z][A-Z][A-Z]);'
   6           '([0-9]+)/([0-9]+),([0-9]+)/([0-9]+)$')
   7
   8 tzprog = None
   9
  10 def tzparse(tzstr):
  11         global tzprog
  12         if tzprog == None:
  13                 import re
  14                 tzprog = re.compile(tzpat)
  15         match = tzprog.match(tzstr)
  16         if not match:
  17                 raise ValueError, 'not the TZ syntax I understand'
  18         subs = []
  19         for i in range(1, 8):
  20                 subs.append(match.group(i))
  21         for i in (1, 3, 4, 5, 6):
  22                 subs[i] = eval(subs[i])
  23         [tzname, delta, dstname, daystart, hourstart, dayend, hourend] = subs
  24         return (tzname, delta, dstname, daystart, hourstart, dayend, hourend)
  25
  26 def tzlocaltime(secs, params):
  27         import time
  28         (tzname, delta, dstname, daystart, hourstart, dayend, hourend) = params
  29         year, month, days, hours, mins, secs, yday, wday, isdst = \
  30                 time.gmtime(secs - delta*3600)
  31         if (daystart, hourstart) <= (yday+1, hours) < (dayend, hourend):
  32                 tzname = dstname
  33                 hours = hours + 1
  34         return year, month, days, hours, mins, secs, yday, wday, tzname
  35
  36 def tzset():
  37         global tzparams, timezone, altzone, daylight, tzname
  38         import os
  39         tzstr = os.environ['TZ']
  40         tzparams = tzparse(tzstr)
  41         timezone = tzparams[1] * 3600
  42         altzone = timezone - 3600
  43         daylight = 1
  44         tzname = tzparams[0], tzparams[2]
  45
  46 def isdst(secs):
  47         import time
  48         (tzname, delta, dstname, daystart, hourstart, dayend, hourend) = \
  49                 tzparams
  50         year, month, days, hours, mins, secs, yday, wday, isdst = \
  51                 time.gmtime(secs - delta*3600)
  52         return (daystart, hourstart) <= (yday+1, hours) < (dayend, hourend)
  53
  54 tzset()
  55
  56 def localtime(secs):
  57         return tzlocaltime(secs, tzparams)
  58
  59 def test():
  60         from time import asctime, gmtime
  61         import time, sys
  62         now = time.time()
  63         x = localtime(now)
  64         tm = x[:-1] + (0,)
  65         print 'now =', now, '=', asctime(tm), x[-1]
  66         now = now - now % (24*3600)
  67         if sys.argv[1:]: now = now + eval(sys.argv[1])
  68         x = gmtime(now)
  69         tm = x[:-1] + (0,)
  70         print 'gmtime =', now, '=', asctime(tm), 'yday =', x[-2]
  71         jan1 = now - x[-2]*24*3600
  72         x = localtime(jan1)
  73         tm = x[:-1] + (0,)
  74         print 'jan1 =', jan1, '=', asctime(tm), x[-1]
  75         for d in range(85, 95) + range(265, 275):
  76                 t = jan1 + d*24*3600
  77                 x = localtime(t)
  78                 tm = x[:-1] + (0,)
  79                 print 'd =', d, 't =', t, '=', asctime(tm), x[-1]