tdlight/tdutils/td/utils/port/Clocks.cpp

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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2020
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/utils/port/Clocks.h"
#include <chrono>
#include <ctime>
namespace td {
double Clocks::monotonic() {
// TODO write system specific functions, because std::chrono::steady_clock is steady only under Windows
auto duration = std::chrono::steady_clock::now().time_since_epoch();
return static_cast<double>(std::chrono::duration_cast<std::chrono::nanoseconds>(duration).count()) * 1e-9;
}
double Clocks::system() {
auto duration = std::chrono::system_clock::now().time_since_epoch();
return static_cast<double>(std::chrono::duration_cast<std::chrono::nanoseconds>(duration).count()) * 1e-9;
}
int Clocks::tz_offset() {
// not thread-safe on POSIX, so calculate the offset only once
static int offset = [] {
auto now = std::time(nullptr);
auto time_ptr = std::localtime(&now);
if (time_ptr == nullptr) {
return 0;
}
auto local_time = *time_ptr;
time_ptr = std::gmtime(&now);
if (time_ptr == nullptr) {
return 0;
}
auto utc_time = *time_ptr;
int minute_offset = local_time.tm_min - utc_time.tm_min;
int hour_offset = local_time.tm_hour - utc_time.tm_hour;
int day_offset = local_time.tm_mday - utc_time.tm_mday;
if (day_offset >= 20) {
day_offset = -1;
} else if (day_offset <= -20) {
day_offset = 1;
}
int sec_offset = day_offset * 86400 + hour_offset * 3600 + minute_offset * 60;
if (sec_offset >= 15 * 3600 || sec_offset <= -15 * 3600) {
return 0;
}
return sec_offset / 900 * 900; // round to 900 just in case
}();
return offset;
}
static int init_tz_offset = Clocks::tz_offset();
} // namespace td