"""Parse a timezone specification."""
# XXX Unfinished.
# XXX Only the typical form "XXXhhYYY;ddd/hh,ddd/hh" is currently supported.
tzpat = ('^([A-Z][A-Z][A-Z])([-+]?[0-9]+)([A-Z][A-Z][A-Z]);'
'([0-9]+)/([0-9]+),([0-9]+)/([0-9]+)$')
tzprog = None
def tzparse(tzstr):
"""Given a timezone spec, return a tuple of information
(tzname, delta, dstname, daystart, hourstart, dayend, hourend),
where 'tzname' is the name of the timezone, 'delta' is the offset
in hours from GMT, 'dstname' is the name of the daylight-saving
timezone, and 'daystart'/'hourstart' and 'dayend'/'hourend'
specify the starting and ending points for daylight saving time."""
global tzprog
if tzprog == None:
import re
tzprog = re.compile(tzpat)
match = tzprog.match(tzstr)
if not match:
raise ValueError, 'not the TZ syntax I understand'
subs = []
for i in range(1, 8):
subs.append(match.group(i))
for i in (1, 3, 4, 5, 6):
subs[i] = eval(subs[i])
[tzname, delta, dstname, daystart, hourstart, dayend, hourend] = subs
return (tzname, delta, dstname, daystart, hourstart, dayend, hourend)
def tzlocaltime(secs, params):
"""Given a Unix time in seconds and a tuple of information about
a timezone as returned by tzparse(), return the local time in the
form (year, month, day, hour, min, sec, yday, wday, tzname)."""
import time
(tzname, delta, dstname, daystart, hourstart, dayend, hourend) = params
year, month, days, hours, mins, secs, yday, wday, isdst = \
time.gmtime(secs - delta*3600)
if (daystart, hourstart) <= (yday+1, hours) < (dayend, hourend):
tzname = dstname
hours = hours + 1
return year, month, days, hours, mins, secs, yday, wday, tzname
def tzset():
"""Determine the current timezone from the "TZ" environment variable."""
global tzparams, timezone, altzone, daylight, tzname
import os
tzstr = os.environ['TZ']
tzparams = tzparse(tzstr)
timezone = tzparams[1] * 3600
altzone = timezone - 3600
daylight = 1
tzname = tzparams[0], tzparams[2]
def isdst(secs):
"""Return true if daylight-saving time is in effect for the given
Unix time in the current timezone."""
import time
(tzname, delta, dstname, daystart, hourstart, dayend, hourend) = \
tzparams
year, month, days, hours, mins, secs, yday, wday, isdst = \
time.gmtime(secs - delta*3600)
return (daystart, hourstart) <= (yday+1, hours) < (dayend, hourend)
tzset()
def localtime(secs):
"""Get the local time in the current timezone."""
return tzlocaltime(secs, tzparams)
def test():
from time import asctime,gmtime
import time, sys
now = time.time()
x = localtime(now)
tm = x[:-1] + (0,)
print 'now =', now, '=', asctime(tm), x[-1]
now = now - now % (24*3600)
if sys.argv[1:]: now = now + eval(sys.argv[1])
x = gmtime(now)
tm = x[:-1] + (0,)
print 'gmtime =', now, '=', asctime(tm), 'yday =', x[-2]
jan1 = now - x[-2]*24*3600
x = localtime(jan1)
tm = x[:-1] + (0,)
print 'jan1 =', jan1, '=', asctime(tm), x[-1]
for d in range(85, 95) + range(265, 275):
t = jan1 + d*24*3600
x = localtime(t)
tm = x[:-1] + (0,)
print 'd =', d, 't =', t, '=', asctime(tm), x[-1]
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