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// Copyright 2016 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#if defined(_WIN32) || defined(_WIN64)
#define _CRT_SECURE_NO_WARNINGS 1
#endif
#include "time_zone_libc.h"
#include <chrono>
#include <ctime>
#include <tuple>
#include <utility>
#include "absl/time/internal/cctz/include/cctz/civil_time.h"
#include "absl/time/internal/cctz/include/cctz/time_zone.h"
namespace absl {
namespace time_internal {
namespace cctz {
namespace {
// .first is seconds east of UTC; .second is the time-zone abbreviation.
using OffsetAbbr = std::pair<int, const char*>;
// Defines a function that can be called as follows:
//
// std::tm tm = ...;
// OffsetAbbr off_abbr = get_offset_abbr(tm);
//
#if defined(_WIN32) || defined(_WIN64)
// Uses the globals: '_timezone', '_dstbias' and '_tzname'.
OffsetAbbr get_offset_abbr(const std::tm& tm) {
const bool is_dst = tm.tm_isdst > 0;
const int off = _timezone + (is_dst ? _dstbias : 0);
const char* abbr = _tzname[is_dst];
return {off, abbr};
}
#elif defined(__sun)
// Uses the globals: 'timezone', 'altzone' and 'tzname'.
OffsetAbbr get_offset_abbr(const std::tm& tm) {
const bool is_dst = tm.tm_isdst > 0;
const int off = is_dst ? altzone : timezone;
const char* abbr = tzname[is_dst];
return {off, abbr};
}
#elif defined(__native_client__) || defined(__myriad2__) || \
defined(__EMSCRIPTEN__)
// Uses the globals: 'timezone' and 'tzname'.
OffsetAbbr get_offset_abbr(const std::tm& tm) {
const bool is_dst = tm.tm_isdst > 0;
const int off = _timezone + (is_dst ? 60 * 60 : 0);
const char* abbr = tzname[is_dst];
return {off, abbr};
}
#else
//
// Returns an OffsetAbbr using std::tm fields with various spellings.
//
#if !defined(tm_gmtoff) && !defined(tm_zone)
template <typename T>
OffsetAbbr get_offset_abbr(const T& tm, decltype(&T::tm_gmtoff) = nullptr,
decltype(&T::tm_zone) = nullptr) {
return {tm.tm_gmtoff, tm.tm_zone};
}
#endif // !defined(tm_gmtoff) && !defined(tm_zone)
#if !defined(__tm_gmtoff) && !defined(__tm_zone)
template <typename T>
OffsetAbbr get_offset_abbr(const T& tm, decltype(&T::__tm_gmtoff) = nullptr,
decltype(&T::__tm_zone) = nullptr) {
return {tm.__tm_gmtoff, tm.__tm_zone};
}
#endif // !defined(__tm_gmtoff) && !defined(__tm_zone)
#endif
} // namespace
TimeZoneLibC::TimeZoneLibC(const std::string& name)
: local_(name == "localtime") {}
time_zone::absolute_lookup TimeZoneLibC::BreakTime(
const time_point<seconds>& tp) const {
time_zone::absolute_lookup al;
std::time_t t = ToUnixSeconds(tp);
std::tm tm;
if (local_) {
#if defined(_WIN32) || defined(_WIN64)
localtime_s(&tm, &t);
#else
localtime_r(&t, &tm);
#endif
std::tie(al.offset, al.abbr) = get_offset_abbr(tm);
} else {
#if defined(_WIN32) || defined(_WIN64)
gmtime_s(&tm, &t);
#else
gmtime_r(&t, &tm);
#endif
al.offset = 0;
al.abbr = "UTC";
}
al.cs = civil_second(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
tm.tm_hour, tm.tm_min, tm.tm_sec);
al.is_dst = tm.tm_isdst > 0;
return al;
}
time_zone::civil_lookup TimeZoneLibC::MakeTime(const civil_second& cs) const {
time_zone::civil_lookup cl;
std::time_t t;
if (local_) {
// Does not handle SKIPPED/AMBIGUOUS or huge years.
std::tm tm;
tm.tm_year = static_cast<int>(cs.year() - 1900);
tm.tm_mon = cs.month() - 1;
tm.tm_mday = cs.day();
tm.tm_hour = cs.hour();
tm.tm_min = cs.minute();
tm.tm_sec = cs.second();
tm.tm_isdst = -1;
t = std::mktime(&tm);
} else {
t = cs - civil_second();
}
cl.kind = time_zone::civil_lookup::UNIQUE;
cl.pre = cl.trans = cl.post = FromUnixSeconds(t);
return cl;
}
bool TimeZoneLibC::NextTransition(const time_point<seconds>& tp,
time_zone::civil_transition* trans) const {
return false;
}
bool TimeZoneLibC::PrevTransition(const time_point<seconds>& tp,
time_zone::civil_transition* trans) const {
return false;
}
std::string TimeZoneLibC::Version() const {
return std::string(); // unknown
}
std::string TimeZoneLibC::Description() const {
return local_ ? "localtime" : "UTC";
}
} // namespace cctz
} // namespace time_internal
} // namespace absl
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