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 regex
  14                 tzprog = regex.compile(tzpat)
  15         if tzprog.match(tzstr) < 0:
  16                 raise ValueError, 'not the TZ syntax I understand'
  17         regs = tzprog.regs
  18         subs = []
  19         for i in range(1, 8):
  20                 a, b = regs[i]
  21                 subs.append(tzstr[a:b])
  22         for i in (1, 3, 4, 5, 6):
  23                 subs[i] = eval(subs[i])
  24         [tzname, delta, dstname, daystart, hourstart, dayend, hourend] = subs
  25         return (tzname, delta, dstname, daystart, hourstart, dayend, hourend)
  26
  27 def tzlocaltime(secs, params):
  28         import time
  29         (tzname, delta, dstname, daystart, hourstart, dayend, hourend) = params
  30         year, month, days, hours, mins, secs, yday, wday, isdst = \
  31                 time.gmtime(secs - delta*3600)
  32         if (daystart, hourstart) <= (yday+1, hours) < (dayend, hourend):
  33                 tzname = dstname
  34                 hours = hours + 1
  35         return year, month, days, hours, mins, secs, yday, wday, tzname
  36
  37 def tzset():
  38         global tzparams, timezone, altzone, daylight, tzname
  39         import os
  40         tzstr = os.environ['TZ']
  41         tzparams = tzparse(tzstr)
  42         timezone = tzparams[1] * 3600
  43         altzone = timezone - 3600
  44         daylight = 1
  45         tzname = tzparams[0], tzparams[2]
  46
  47 def isdst(secs):
  48         import time
  49         (tzname, delta, dstname, daystart, hourstart, dayend, hourend) = \
  50                 tzparams
  51         year, month, days, hours, mins, secs, yday, wday, isdst = \
  52                 time.gmtime(secs - delta*3600)
  53         return (daystart, hourstart) <= (yday+1, hours) < (dayend, hourend)
  54
  55 tzset()
  56
  57 def localtime(secs):
  58         return tzlocaltime(secs, tzparams)
  59
  60 def test():
  61         from time import asctime, gmtime
  62         import time, sys
  63         now = time.time()
  64         x = localtime(now)
  65         tm = x[:-1] + (0,)
  66         print 'now =', now, '=', asctime(tm), x[-1]
  67         now = now - now % (24*3600)
  68         if sys.argv[1:]: now = now + eval(sys.argv[1])
  69         x = gmtime(now)
  70         tm = x[:-1] + (0,)
  71         print 'gmtime =', now, '=', asctime(tm), 'yday =', x[-2]
  72         jan1 = now - x[-2]*24*3600
  73         x = localtime(jan1)
  74         tm = x[:-1] + (0,)
  75         print 'jan1 =', jan1, '=', asctime(tm), x[-1]
  76         for d in range(85, 95) + range(265, 275):
  77                 t = jan1 + d*24*3600
  78                 x = localtime(t)
  79                 tm = x[:-1] + (0,)
  80                 print 'd =', d, 't =', t, '=', asctime(tm), x[-1]