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comparison CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/lib/python3.8/site-packages/pytz/tzfile.py @ 69:33d812a61356

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planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d
author jpayne
date Tue, 18 Mar 2025 17:55:14 -0400
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67:0e9998148a16 69:33d812a61356
1 '''
2 $Id: tzfile.py,v 1.8 2004/06/03 00:15:24 zenzen Exp $
3 '''
4
5 from datetime import datetime
6 from struct import unpack, calcsize
7
8 from pytz.tzinfo import StaticTzInfo, DstTzInfo, memorized_ttinfo
9 from pytz.tzinfo import memorized_datetime, memorized_timedelta
10
11
12 def _byte_string(s):
13 """Cast a string or byte string to an ASCII byte string."""
14 return s.encode('ASCII')
15
16 _NULL = _byte_string('\0')
17
18
19 def _std_string(s):
20 """Cast a string or byte string to an ASCII string."""
21 return str(s.decode('ASCII'))
22
23
24 def build_tzinfo(zone, fp):
25 head_fmt = '>4s c 15x 6l'
26 head_size = calcsize(head_fmt)
27 (magic, format, ttisgmtcnt, ttisstdcnt, leapcnt, timecnt,
28 typecnt, charcnt) = unpack(head_fmt, fp.read(head_size))
29
30 # Make sure it is a tzfile(5) file
31 assert magic == _byte_string('TZif'), 'Got magic %s' % repr(magic)
32
33 # Read out the transition times, localtime indices and ttinfo structures.
34 data_fmt = '>%(timecnt)dl %(timecnt)dB %(ttinfo)s %(charcnt)ds' % dict(
35 timecnt=timecnt, ttinfo='lBB' * typecnt, charcnt=charcnt)
36 data_size = calcsize(data_fmt)
37 data = unpack(data_fmt, fp.read(data_size))
38
39 # make sure we unpacked the right number of values
40 assert len(data) == 2 * timecnt + 3 * typecnt + 1
41 transitions = [memorized_datetime(trans)
42 for trans in data[:timecnt]]
43 lindexes = list(data[timecnt:2 * timecnt])
44 ttinfo_raw = data[2 * timecnt:-1]
45 tznames_raw = data[-1]
46 del data
47
48 # Process ttinfo into separate structs
49 ttinfo = []
50 tznames = {}
51 i = 0
52 while i < len(ttinfo_raw):
53 # have we looked up this timezone name yet?
54 tzname_offset = ttinfo_raw[i + 2]
55 if tzname_offset not in tznames:
56 nul = tznames_raw.find(_NULL, tzname_offset)
57 if nul < 0:
58 nul = len(tznames_raw)
59 tznames[tzname_offset] = _std_string(
60 tznames_raw[tzname_offset:nul])
61 ttinfo.append((ttinfo_raw[i],
62 bool(ttinfo_raw[i + 1]),
63 tznames[tzname_offset]))
64 i += 3
65
66 # Now build the timezone object
67 if len(ttinfo) == 1 or len(transitions) == 0:
68 ttinfo[0][0], ttinfo[0][2]
69 cls = type(zone, (StaticTzInfo,), dict(
70 zone=zone,
71 _utcoffset=memorized_timedelta(ttinfo[0][0]),
72 _tzname=ttinfo[0][2]))
73 else:
74 # Early dates use the first standard time ttinfo
75 i = 0
76 while ttinfo[i][1]:
77 i += 1
78 if ttinfo[i] == ttinfo[lindexes[0]]:
79 transitions[0] = datetime.min
80 else:
81 transitions.insert(0, datetime.min)
82 lindexes.insert(0, i)
83
84 # calculate transition info
85 transition_info = []
86 for i in range(len(transitions)):
87 inf = ttinfo[lindexes[i]]
88 utcoffset = inf[0]
89 if not inf[1]:
90 dst = 0
91 else:
92 for j in range(i - 1, -1, -1):
93 prev_inf = ttinfo[lindexes[j]]
94 if not prev_inf[1]:
95 break
96 dst = inf[0] - prev_inf[0] # dst offset
97
98 # Bad dst? Look further. DST > 24 hours happens when
99 # a timzone has moved across the international dateline.
100 if dst <= 0 or dst > 3600 * 3:
101 for j in range(i + 1, len(transitions)):
102 stdinf = ttinfo[lindexes[j]]
103 if not stdinf[1]:
104 dst = inf[0] - stdinf[0]
105 if dst > 0:
106 break # Found a useful std time.
107
108 tzname = inf[2]
109
110 # Round utcoffset and dst to the nearest minute or the
111 # datetime library will complain. Conversions to these timezones
112 # might be up to plus or minus 30 seconds out, but it is
113 # the best we can do.
114 utcoffset = int((utcoffset + 30) // 60) * 60
115 dst = int((dst + 30) // 60) * 60
116 transition_info.append(memorized_ttinfo(utcoffset, dst, tzname))
117
118 cls = type(zone, (DstTzInfo,), dict(
119 zone=zone,
120 _utc_transition_times=transitions,
121 _transition_info=transition_info))
122
123 return cls()
124
125 if __name__ == '__main__':
126 import os.path
127 from pprint import pprint
128 base = os.path.join(os.path.dirname(__file__), 'zoneinfo')
129 tz = build_tzinfo('Australia/Melbourne',
130 open(os.path.join(base, 'Australia', 'Melbourne'), 'rb'))
131 tz = build_tzinfo('US/Eastern',
132 open(os.path.join(base, 'US', 'Eastern'), 'rb'))
133 pprint(tz._utc_transition_times)