QDate::toStdSysDays is needlessly behind __cpp_lib_chrono >= 201907L

scwx-qt/source/scwx/qt/util/time.cpp

@@ -0,0 +1,24 @@
+#include <scwx/qt/util/time.hpp>
+
+namespace scwx
+{
+namespace qt
+{
+namespace util
+{
+
+std::chrono::sys_days SysDays(const QDate& date)
+{
+   using namespace std::chrono;
+   using sys_days             = time_point<system_clock, days>;
+   constexpr auto julianEpoch = sys_days {-4713y / November / 24d};
+   constexpr auto unixEpoch   = sys_days {1970y / January / 1d};
+   constexpr auto offset      = std::chrono::days(julianEpoch - unixEpoch);
+
+   return std::chrono::sys_days(std::chrono::days(date.toJulianDay()) +
+                                julianEpoch);
+}
+
+} // namespace util
+} // namespace qt
+} // namespace scwx