forked from suyu/suyu
3979c7daa4
Moves it from Settings to Common::TimeZone, since this algorithm doesn't depend on the setting. It also lets us use it in other libraries. common: Various fixes time_zone: Don't double up the std::abs Too many absolute values were causing mirrored time zones to resolve as the same.
115 lines
4 KiB
C++
115 lines
4 KiB
C++
// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
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// SPDX-License-Identifier: GPL-2.0-or-later
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#include <chrono>
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#include <iomanip>
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#include <sstream>
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#include <fmt/chrono.h>
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#include <fmt/core.h>
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#include "common/logging/log.h"
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#include "common/settings.h"
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#include "common/time_zone.h"
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namespace Common::TimeZone {
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// Time zone strings
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constexpr std::array timezones{
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"GMT", "GMT", "CET", "CST6CDT", "Cuba", "EET", "Egypt", "Eire",
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"EST", "EST5EDT", "GB", "GB-Eire", "GMT", "GMT+0", "GMT-0", "GMT0",
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"Greenwich", "Hongkong", "HST", "Iceland", "Iran", "Israel", "Jamaica", "Japan",
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"Kwajalein", "Libya", "MET", "MST", "MST7MDT", "Navajo", "NZ", "NZ-CHAT",
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"Poland", "Portugal", "PRC", "PST8PDT", "ROC", "ROK", "Singapore", "Turkey",
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"UCT", "Universal", "UTC", "W-SU", "WET", "Zulu",
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};
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const std::array<const char*, 46>& GetTimeZoneStrings() {
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return timezones;
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}
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std::string GetDefaultTimeZone() {
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return "GMT";
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}
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static std::string GetOsTimeZoneOffset() {
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const std::time_t t{std::time(nullptr)};
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const std::tm tm{*std::localtime(&t)};
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return fmt::format("{:%z}", tm);
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}
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static int ConvertOsTimeZoneOffsetToInt(const std::string& timezone) {
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try {
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return std::stoi(timezone);
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} catch (const std::invalid_argument&) {
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LOG_CRITICAL(Common, "invalid_argument with {}!", timezone);
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return 0;
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} catch (const std::out_of_range&) {
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LOG_CRITICAL(Common, "out_of_range with {}!", timezone);
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return 0;
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}
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}
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std::chrono::seconds GetCurrentOffsetSeconds() {
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const int offset{ConvertOsTimeZoneOffsetToInt(GetOsTimeZoneOffset())};
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int seconds{(offset / 100) * 60 * 60}; // Convert hour component to seconds
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seconds += (offset % 100) * 60; // Convert minute component to seconds
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return std::chrono::seconds{seconds};
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}
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std::string FindSystemTimeZone() {
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#if defined(MINGW)
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// MinGW has broken strftime -- https://sourceforge.net/p/mingw-w64/bugs/793/
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// e.g. fmt::format("{:%z}") -- returns "Eastern Daylight Time" when it should be "-0400"
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return timezones[0];
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#else
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// Time zone offset in seconds from GMT
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constexpr std::array offsets{
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0, 0, 3600, -21600, -19768, 7200, 7509, -1521, -18000, -18000, -75, -75,
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0, 0, 0, 0, 0, 27402, -36000, -968, 12344, 8454, -18430, 33539,
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40160, 3164, 3600, -25200, -25200, -25196, 41944, 44028, 5040, -2205, 29143, -28800,
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29160, 30472, 24925, 6952, 0, 0, 0, 9017, 0, 0,
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};
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// If the time zone recognizes Daylight Savings Time
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constexpr std::array dst{
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false, false, true, true, true, true, true, true, false, true, true, true,
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false, false, false, false, false, true, false, false, true, true, true, true,
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false, true, true, false, true, true, true, true, true, true, true, true,
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true, true, true, true, false, false, false, true, true, false,
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};
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static std::string system_time_zone_cached{};
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if (!system_time_zone_cached.empty()) {
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return system_time_zone_cached;
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}
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const auto now = std::time(nullptr);
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const struct std::tm& local = *std::localtime(&now);
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const s64 system_offset = GetCurrentOffsetSeconds().count() - (local.tm_isdst ? 3600 : 0);
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int min = std::numeric_limits<int>::max();
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int min_index = -1;
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for (u32 i = 2; i < offsets.size(); i++) {
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// Skip if system is celebrating DST but considered time zone does not
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if (local.tm_isdst && !dst[i]) {
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continue;
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}
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const auto offset = offsets[i];
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const int difference = static_cast<int>(std::abs(offset - system_offset));
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if (difference < min) {
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min = difference;
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min_index = i;
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}
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}
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system_time_zone_cached = GetTimeZoneStrings()[min_index];
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return system_time_zone_cached;
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#endif
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}
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} // namespace Common::TimeZone
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