dt: tm <-> datetime conversion

code/espurna/datetime.cpp

@@ -152,10 +152,34 @@ Seconds to_seconds(const Date& date, const HhMmSs& hh_mm_ss) noexcept {
  return out;
 }
 
+tm DateHhMmSs::c_value() const noexcept {
+ tm out{};
+ out.tm_isdst = -1;
+
+ out.tm_year = year - 1900;
+ out.tm_mon = month - 1;
+ out.tm_mday = day;
+
+ out.tm_hour = hours;
+ out.tm_min = minutes;
+ out.tm_sec = seconds;
+
+ return out;
+}
+
 Seconds to_seconds(const tm& t) noexcept {
  return to_seconds(make_date(t), make_hh_mm_ss(t));
 }
 
+Seconds to_seconds(const DateHhMmSs& datetime, bool utc) noexcept {
+ if (utc) {
+ return to_seconds(Date(datetime), HhMmSs(datetime));
+ }
+
+ auto c_value = datetime.c_value();
+ return Seconds{ mktime(&c_value) };
+}
+
 Context make_context(Seconds seconds) {
  return make_context(seconds.count());
 }

code/espurna/datetime.h

@@ -68,6 +68,10 @@ constexpr HhMmSs make_hh_mm_ss(const tm& t) {
  };
 }
 
+struct DateHhMmSs : public Date, public HhMmSs {
+ tm c_value() const noexcept;
+};
+
 Date from_days(const Days&) noexcept;
 
 // on esp8266 this is a usually an internal timestamp timeshift'ed with `micros64()`
@@ -185,6 +189,9 @@ constexpr Weekday next(Weekday day) {
 Seconds to_seconds(const Date&, const HhMmSs&) noexcept;
 Seconds to_seconds(const tm&) noexcept;
 
+// Either local or UTC conversion
+Seconds to_seconds(const DateHhMmSs&, bool) noexcept;
+
 // main use-case is scheduler, and it needs both tm results
 struct Context {
  time_t timestamp;