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_IF_H_
16#define ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_IF_H_
17
18#include <chrono>
19#include <cstdint>
20#include <memory>
21#include <string>
22
23#include "absl/time/internal/cctz/include/cctz/civil_time.h"
24#include "absl/time/internal/cctz/include/cctz/time_zone.h"
25
26namespace absl {
27namespace time_internal {
28namespace cctz {
29
30// A simple interface used to hide time-zone complexities from time_zone::Impl.
31// Subclasses implement the functions for civil-time conversions in the zone.
32class TimeZoneIf {
33 public:
34 // A factory function for TimeZoneIf implementations.
35 static std::unique_ptr<TimeZoneIf> Load(const std::string& name);
36
37 virtual ~TimeZoneIf();
38
39 virtual time_zone::absolute_lookup BreakTime(
40 const time_point<seconds>& tp) const = 0;
41 virtual time_zone::civil_lookup MakeTime(
42 const civil_second& cs) const = 0;
43
44 virtual bool NextTransition(const time_point<seconds>& tp,
45 time_zone::civil_transition* trans) const = 0;
46 virtual bool PrevTransition(const time_point<seconds>& tp,
47 time_zone::civil_transition* trans) const = 0;
48
49 virtual std::string Version() const = 0;
50 virtual std::string Description() const = 0;
51
52 protected:
53 TimeZoneIf() {}
54};
55
56// Convert between time_point<seconds> and a count of seconds since the
57// Unix epoch. We assume that the std::chrono::system_clock and the
58// Unix clock are second aligned, but not that they share an epoch.
59inline std::int_fast64_t ToUnixSeconds(const time_point<seconds>& tp) {
60 return (tp - std::chrono::time_point_cast<seconds>(
61 std::chrono::system_clock::from_time_t(0))).count();
62}
63inline time_point<seconds> FromUnixSeconds(std::int_fast64_t t) {
64 return std::chrono::time_point_cast<seconds>(
65 std::chrono::system_clock::from_time_t(0)) + seconds(t);
66}
67
68} // namespace cctz
69} // namespace time_internal
70} // namespace absl
71
72#endif // ABSL_TIME_INTERNAL_CCTZ_TIME_ZONE_IF_H_
73