tdlight/tdutils/td/utils/port/Clocks.cpp
2022-01-01 03:35:39 +03:00

99 lines
2.7 KiB
C++

//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2022
//
// 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 "td/utils/port/platform.h"
#include <chrono>
#include <ctime>
#if TD_PORT_POSIX
#include <time.h>
#endif
namespace td {
double Clocks::monotonic() {
#if TD_PORT_POSIX
// use system specific functions, because std::chrono::steady_clock is steady only under Windows
#ifdef CLOCK_BOOTTIME
{
static bool skip = [] {
struct timespec spec;
return clock_gettime(CLOCK_BOOTTIME, &spec) != 0;
}();
struct timespec spec;
if (!skip && clock_gettime(CLOCK_BOOTTIME, &spec) == 0) {
return static_cast<double>(spec.tv_nsec) * 1e-9 + static_cast<double>(spec.tv_sec);
}
}
#endif
#ifdef CLOCK_MONOTONIC_RAW
{
static bool skip = [] {
struct timespec spec;
return clock_gettime(CLOCK_MONOTONIC_RAW, &spec) != 0;
}();
struct timespec spec;
if (!skip && clock_gettime(CLOCK_MONOTONIC_RAW, &spec) == 0) {
return static_cast<double>(spec.tv_nsec) * 1e-9 + static_cast<double>(spec.tv_sec);
}
}
#endif
#endif
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;
}
namespace detail {
int init_tz_offset_private = Clocks::tz_offset();
} // namespace detail
} // namespace td