tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
Log | Files | Refs | README | LICENSE

time_zone_posix.h (4023B)

      1 // Copyright 2016 Google Inc. All Rights Reserved.
      2 //
      3 // Licensed under the Apache License, Version 2.0 (the "License");
      4 // you may not use this file except in compliance with the License.
      5 // You may obtain a copy of the License at
      6 //
      7 //   https://www.apache.org/licenses/LICENSE-2.0
      8 //
      9 //   Unless required by applicable law or agreed to in writing, software
     10 //   distributed under the License is distributed on an "AS IS" BASIS,
     11 //   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     12 //   See the License for the specific language governing permissions and
     13 //   limitations under the License.
     14 
     15 // Parsing of a POSIX zone spec as described in the TZ part of section 8.3 in
     16 // http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap08.html.
     17 //
     18 // The current POSIX spec for America/Los_Angeles is "PST8PDT,M3.2.0,M11.1.0",
     19 // which would be broken down as ...
     20 //
     21 //   PosixTimeZone {
     22 //     std_abbr = "PST"
     23 //     std_offset = -28800
     24 //     dst_abbr = "PDT"
     25 //     dst_offset = -25200
     26 //     dst_start = PosixTransition {
     27 //       date {
     28 //         m {
     29 //           month = 3
     30 //           week = 2
     31 //           weekday = 0
     32 //         }
     33 //       }
     34 //       time {
     35 //         offset = 7200
     36 //       }
     37 //     }
     38 //     dst_end = PosixTransition {
     39 //       date {
     40 //         m {
     41 //           month = 11
     42 //           week = 1
     43 //           weekday = 0
     44 //         }
     45 //       }
     46 //       time {
     47 //         offset = 7200
     48 //       }
     49 //     }
     50 //   }
     51 
     52 #ifndef ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_POSIX_H_
     53 #define ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_POSIX_H_
     54 
     55 #include <cstdint>
     56 #include <string>
     57 
     58 #include "absl/base/config.h"
     59 
     60 namespace absl {
     61 ABSL_NAMESPACE_BEGIN
     62 namespace time_internal {
     63 namespace cctz {
     64 
     65 // The date/time of the transition. The date is specified as either:
     66 // (J) the Nth day of the year (1 <= N <= 365), excluding leap days, or
     67 // (N) the Nth day of the year (0 <= N <= 365), including leap days, or
     68 // (M) the Nth weekday of a month (e.g., the 2nd Sunday in March).
     69 // The time, specified as a day offset, identifies the particular moment
     70 // of the transition, and may be negative or >= 24h, and in which case
     71 // it would take us to another day, and perhaps week, or even month.
     72 struct PosixTransition {
     73  enum DateFormat { J, N, M };
     74 
     75  struct Date {
     76    struct NonLeapDay {
     77      std::int_fast16_t day;  // day of non-leap year [1:365]
     78    };
     79    struct Day {
     80      std::int_fast16_t day;  // day of year [0:365]
     81    };
     82    struct MonthWeekWeekday {
     83      std::int_fast8_t month;    // month of year [1:12]
     84      std::int_fast8_t week;     // week of month [1:5] (5==last)
     85      std::int_fast8_t weekday;  // 0==Sun, ..., 6=Sat
     86    };
     87 
     88    DateFormat fmt;
     89 
     90    union {
     91      NonLeapDay j;
     92      Day n;
     93      MonthWeekWeekday m;
     94    };
     95  };
     96 
     97  struct Time {
     98    std::int_fast32_t offset;  // seconds before/after 00:00:00
     99  };
    100 
    101  Date date;
    102  Time time;
    103 };
    104 
    105 // The entirety of a POSIX-string specified time-zone rule. The standard
    106 // abbreviation and offset are always given. If the time zone includes
    107 // daylight saving, then the daylight abbreviation is non-empty and the
    108 // remaining fields are also valid. Note that the start/end transitions
    109 // are not ordered---in the southern hemisphere the transition to end
    110 // daylight time occurs first in any particular year.
    111 struct PosixTimeZone {
    112  std::string std_abbr;
    113  std::int_fast32_t std_offset;
    114 
    115  std::string dst_abbr;
    116  std::int_fast32_t dst_offset;
    117  PosixTransition dst_start;
    118  PosixTransition dst_end;
    119 };
    120 
    121 // Breaks down a POSIX time-zone specification into its constituent pieces,
    122 // filling in any missing values (DST offset, or start/end transition times)
    123 // with the standard-defined defaults. Returns false if the specification
    124 // could not be parsed (although some fields of *res may have been altered).
    125 bool ParsePosixSpec(const std::string& spec, PosixTimeZone* res);
    126 
    127 }  // namespace cctz
    128 }  // namespace time_internal
    129 ABSL_NAMESPACE_END
    130 }  // namespace absl
    131 
    132 #endif  // ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_POSIX_H_