diff options
Diffstat (limited to '')
| -rw-r--r-- | src/common/time_zone.cpp | 64 |
1 files changed, 26 insertions, 38 deletions
diff --git a/src/common/time_zone.cpp b/src/common/time_zone.cpp index 717d751ba..d8d7896c6 100644 --- a/src/common/time_zone.cpp +++ b/src/common/time_zone.cpp @@ -2,8 +2,10 @@ // SPDX-License-Identifier: GPL-2.0-or-later #include <chrono> +#include <exception> #include <iomanip> #include <sstream> +#include <stdexcept> #include <fmt/chrono.h> #include <fmt/core.h> @@ -59,56 +61,42 @@ std::chrono::seconds GetCurrentOffsetSeconds() { return std::chrono::seconds{seconds}; } +// Key is [Hours * 100 + Minutes], multiplied by 100 if DST +const static std::map<s64, const char*> off_timezones = { + {530, "Asia/Calcutta"}, {930, "Australia/Darwin"}, {845, "Australia/Eucla"}, + {103000, "Australia/Adelaide"}, {1030, "Australia/Lord_Howe"}, {630, "Indian/Cocos"}, + {1245, "Pacific/Chatham"}, {134500, "Pacific/Chatham"}, {-330, "Canada/Newfoundland"}, + {-23000, "Canada/Newfoundland"}, {430, "Asia/Kabul"}, {330, "Asia/Tehran"}, + {43000, "Asia/Tehran"}, {545, "Asia/Kathmandu"}, {-930, "Asia/Marquesas"}, +}; + std::string FindSystemTimeZone() { #if defined(MINGW) // MinGW has broken strftime -- https://sourceforge.net/p/mingw-w64/bugs/793/ // e.g. fmt::format("{:%z}") -- returns "Eastern Daylight Time" when it should be "-0400" return timezones[0]; #else - // Time zone offset in seconds from GMT - constexpr std::array offsets{ - 0, 0, 3600, -21600, -19768, 7200, 7509, -1521, -18000, -18000, -75, -75, - 0, 0, 0, 0, 0, 27402, -36000, -968, 12344, 8454, -18430, 33539, - 40160, 3164, 3600, -25200, -25200, -25196, 41944, 44028, 5040, -2205, 29143, -28800, - 29160, 30472, 24925, 6952, 0, 0, 0, 9017, 0, 0, - }; - - // If the time zone recognizes Daylight Savings Time - constexpr std::array dst{ - false, false, true, true, true, true, true, true, false, true, true, true, - false, false, false, false, false, true, false, false, true, true, true, true, - false, true, true, false, true, true, true, true, true, true, true, true, - true, true, true, true, false, false, false, true, true, false, - }; - - static std::string system_time_zone_cached{}; - if (!system_time_zone_cached.empty()) { - return system_time_zone_cached; - } + const s64 seconds = static_cast<s64>(GetCurrentOffsetSeconds().count()); - const auto now = std::time(nullptr); - const struct std::tm& local = *std::localtime(&now); + const s64 minutes = seconds / 60; + const s64 hours = minutes / 60; - const s64 system_offset = GetCurrentOffsetSeconds().count() - (local.tm_isdst ? 3600 : 0); + const s64 minutes_off = minutes - hours * 60; - int min = std::numeric_limits<int>::max(); - int min_index = -1; - for (u32 i = 2; i < offsets.size(); i++) { - // Skip if system is celebrating DST but considered time zone does not - if (local.tm_isdst && !dst[i]) { - continue; - } + if (minutes_off != 0) { + const auto the_time = std::time(nullptr); + const struct std::tm& local = *std::localtime(&the_time); + const bool is_dst = local.tm_isdst != 0; + + const s64 tz_index = (hours * 100 + minutes_off) * (is_dst ? 100 : 1); - const auto offset = offsets[i]; - const int difference = static_cast<int>(std::abs(offset - system_offset)); - if (difference < min) { - min = difference; - min_index = i; + try { + return off_timezones.at(tz_index); + } catch (std::out_of_range&) { + LOG_ERROR(Common, "Time zone {} not handled, defaulting to hour offset.", tz_index); } } - - system_time_zone_cached = GetTimeZoneStrings()[min_index]; - return system_time_zone_cached; + return fmt::format("Etc/GMT{:s}{:d}", hours > 0 ? "-" : "+", std::abs(hours)); #endif } |