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$Id: tzfile.py,v 1.1 2003/04/23 01:25:54 zenzen Exp $
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__rcs_id__ = '$Id: tzfile.py,v 1.1 2003/04/23 01:25:54 zenzen Exp $'
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__version__ = '$Revision: 1.1 $'[11:-2]
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from struct import unpack,calcsize
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''' Wrapper around a tzfile(5) format file as generated by zic(1) '''
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def __init__(self,filename):
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# See elsie.nci.nih.gov/src/tzfile.5 for details of the file format
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head_size = calcsize(head_fmt)
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(magic,ttisgmtcnt,ttisstdcnt,leapcnt,timecnt,typecnt,charcnt) = \
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unpack(head_fmt,inf.read(head_size))
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# Make sure it is a tzinfo(5) file
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assert magic == 'TZif'
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# Our transition times
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transitions_fmt = '>%dl' % (timecnt)
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transitions_size = calcsize(transitions_fmt)
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transitions = unpack(transitions_fmt,inf.read(transitions_size))
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# Our indexes into the local time structures
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lindexes = unpack('%dB' % (timecnt),inf.read(timecnt))
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# Our ttinfo structures, detailing gmtoffset, isdst and abbriv index
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ttinfo_size = calcsize(ttinfo_fmt)
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unpack(ttinfo_fmt,inf.read(ttinfo_size)) for i in xrange(0,typecnt)
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# Our timezone abbreviations, stored suckily as null terminated strings
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tznames = raw.split('\0',charcnt)[:-1]
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print '%d Transitions' % len(transitions)
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print '%d lindexes' % len(lindexes)
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print '%d ttinfo: %s' % (len(ttinfo),repr(ttinfo))
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print '%d tznames: %s' % (len(tznames),repr(tznames))
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self.transitions = [ (
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transitions[i], # epoch time of transition
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ttinfo[lindexes[i]][0], # utc offset in seconds
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ttinfo[lindexes[i]][1], # is DST
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tznames[ttinfo[lindexes[i]][2]] # timezone abbreviation
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) for i in xrange(0,len(transitions)) ]
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return repr(self.transitions)
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if __name__ == '__main__':
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base = os.path.join('elsie.nci.nih.gov','build','etc','zoneinfo')
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tz = TZFile(os.path.join(base,'Australia','Melbourne'))
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tz = TZFile(os.path.join(base,'US','Central'))
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tz = TZFile(os.path.join(base,'US','Eastern'))
added
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tzfile.py
