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-rw-r--r--src/common/time_zone.cpp64
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
}