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 | #ifndef ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_INFO_H_ |
16 | #define ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_INFO_H_ |
17 | |
18 | #include <atomic> |
19 | #include <cstddef> |
20 | #include <cstdint> |
21 | #include <string> |
22 | #include <vector> |
23 | |
24 | #include "absl/time/internal/cctz/include/cctz/civil_time.h" |
25 | #include "absl/time/internal/cctz/include/cctz/time_zone.h" |
26 | #include "absl/time/internal/cctz/include/cctz/zone_info_source.h" |
27 | #include "time_zone_if.h" |
28 | #include "tzfile.h" |
29 | |
30 | namespace absl { |
31 | namespace time_internal { |
32 | namespace cctz { |
33 | |
34 | // A transition to a new UTC offset. |
35 | struct Transition { |
36 | std::int_least64_t unix_time; // the instant of this transition |
37 | std::uint_least8_t type_index; // index of the transition type |
38 | civil_second civil_sec; // local civil time of transition |
39 | civil_second prev_civil_sec; // local civil time one second earlier |
40 | |
41 | struct ByUnixTime { |
42 | inline bool operator()(const Transition& lhs, const Transition& rhs) const { |
43 | return lhs.unix_time < rhs.unix_time; |
44 | } |
45 | }; |
46 | struct ByCivilTime { |
47 | inline bool operator()(const Transition& lhs, const Transition& rhs) const { |
48 | return lhs.civil_sec < rhs.civil_sec; |
49 | } |
50 | }; |
51 | }; |
52 | |
53 | // The characteristics of a particular transition. |
54 | struct TransitionType { |
55 | std::int_least32_t utc_offset; // the new prevailing UTC offset |
56 | civil_second civil_max; // max convertible civil time for offset |
57 | civil_second civil_min; // min convertible civil time for offset |
58 | bool is_dst; // did we move into daylight-saving time |
59 | std::uint_least8_t abbr_index; // index of the new abbreviation |
60 | }; |
61 | |
62 | // A time zone backed by the IANA Time Zone Database (zoneinfo). |
63 | class TimeZoneInfo : public TimeZoneIf { |
64 | public: |
65 | TimeZoneInfo() = default; |
66 | TimeZoneInfo(const TimeZoneInfo&) = delete; |
67 | TimeZoneInfo& operator=(const TimeZoneInfo&) = delete; |
68 | |
69 | // Loads the zoneinfo for the given name, returning true if successful. |
70 | bool Load(const std::string& name); |
71 | |
72 | // TimeZoneIf implementations. |
73 | time_zone::absolute_lookup BreakTime( |
74 | const time_point<seconds>& tp) const override; |
75 | time_zone::civil_lookup MakeTime( |
76 | const civil_second& cs) const override; |
77 | bool NextTransition(const time_point<seconds>& tp, |
78 | time_zone::civil_transition* trans) const override; |
79 | bool PrevTransition(const time_point<seconds>& tp, |
80 | time_zone::civil_transition* trans) const override; |
81 | std::string Version() const override; |
82 | std::string Description() const override; |
83 | |
84 | private: |
85 | struct { // counts of: |
86 | std::size_t ; // transition times |
87 | std::size_t ; // transition types |
88 | std::size_t ; // zone abbreviation characters |
89 | std::size_t ; // leap seconds (we expect none) |
90 | std::size_t ; // UTC/local indicators (unused) |
91 | std::size_t ; // standard/wall indicators (unused) |
92 | |
93 | bool (const tzhead& tzh); |
94 | std::size_t (std::size_t time_len) const; |
95 | }; |
96 | |
97 | void CheckTransition(const std::string& name, const TransitionType& tt, |
98 | std::int_fast32_t offset, bool is_dst, |
99 | const std::string& abbr) const; |
100 | bool EquivTransitions(std::uint_fast8_t tt1_index, |
101 | std::uint_fast8_t tt2_index) const; |
102 | void (const std::string& name, const Header& hdr); |
103 | |
104 | bool ResetToBuiltinUTC(const seconds& offset); |
105 | bool Load(const std::string& name, ZoneInfoSource* zip); |
106 | |
107 | // Helpers for BreakTime() and MakeTime(). |
108 | time_zone::absolute_lookup LocalTime(std::int_fast64_t unix_time, |
109 | const TransitionType& tt) const; |
110 | time_zone::absolute_lookup LocalTime(std::int_fast64_t unix_time, |
111 | const Transition& tr) const; |
112 | time_zone::civil_lookup TimeLocal(const civil_second& cs, |
113 | year_t c4_shift) const; |
114 | |
115 | std::vector<Transition> transitions_; // ordered by unix_time and civil_sec |
116 | std::vector<TransitionType> transition_types_; // distinct transition types |
117 | std::uint_fast8_t default_transition_type_; // for before first transition |
118 | std::string abbreviations_; // all the NUL-terminated abbreviations |
119 | |
120 | std::string version_; // the tzdata version if available |
121 | std::string future_spec_; // for after the last zic transition |
122 | bool extended_; // future_spec_ was used to generate transitions |
123 | year_t last_year_; // the final year of the generated transitions |
124 | |
125 | // We remember the transitions found during the last BreakTime() and |
126 | // MakeTime() calls. If the next request is for the same transition we |
127 | // will avoid re-searching. |
128 | mutable std::atomic<std::size_t> local_time_hint_ = {}; // BreakTime() hint |
129 | mutable std::atomic<std::size_t> time_local_hint_ = {}; // MakeTime() hint |
130 | }; |
131 | |
132 | } // namespace cctz |
133 | } // namespace time_internal |
134 | } // namespace absl |
135 | |
136 | #endif // ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_INFO_H_ |
137 | |