Implement struct tm constructor and cast, offset accessor.

src/libqof/qof/gnc-datetime.cpp

@@ -79,16 +79,29 @@ LDT_from_unix_local(const time64 time)
     return LDT(temp, tz);
 }
 
+static LDT
+LDT_from_struct_tm(const struct tm tm)
+{
+    auto tdate = boost::gregorian::date_from_tm(tm);
+    auto tdur = boost::posix_time::time_duration(tm.tm_hour, tm.tm_min,
+						 tm.tm_sec, 0);
+    auto tz = tzp.get(tdate.year());
+    return LDT(PTime(tdate, tdur), tz);
+}
+
 class GncDateTimeImpl
 {
 public:
     GncDateTimeImpl() : m_time(unix_epoch, tzp.get(unix_epoch.date().year())) {}
     GncDateTimeImpl(const time64 time) : m_time(LDT_from_unix_local(time)) {}
+    GncDateTimeImpl(const struct tm tm) : m_time(LDT_from_struct_tm(tm)) {}
     GncDateTimeImpl(PTime&& pt) : m_time(pt, tzp.get(pt.date().year())) {}
     GncDateTimeImpl(LDT&& ldt) : m_time(ldt) {}
 
     operator time64() const;
+    operator struct tm() const;
     void now() { m_time = boost::local_time::local_sec_clock::local_time(tzp.get(boost::gregorian::day_clock::local_day().year())); }
+    long offset() const;
 
 private:
     LDT m_time;
@@ -102,6 +115,18 @@ GncDateTimeImpl::operator time64() const
     return secs;
 }
 
+GncDateTimeImpl::operator struct tm() const
+{
+    return to_tm(m_time);
+}
+
+long
+GncDateTimeImpl::offset() const
+{
+    auto offset = m_time.local_time() - m_time.utc_time();
+    return offset.total_seconds();
+}
+
 /* =================== Presentation-class Implementations ====================*/
 GncDate::GncDate() : m_impl{new GncDateImpl} {}
 GncDate::GncDate(int year, int month, int day) :
@@ -115,7 +140,10 @@ GncDate::today()
 }
 
 GncDateTime::GncDateTime() : m_impl(new GncDateTimeImpl) {}
-GncDateTime::GncDateTime(time64 time) : m_impl(new GncDateTimeImpl(time)) {}
+GncDateTime::GncDateTime(const time64 time) :
+    m_impl(new GncDateTimeImpl(time)) {}
+GncDateTime::GncDateTime(const struct tm tm) :
+    m_impl(new GncDateTimeImpl(tm)) {}
 GncDateTime::~GncDateTime() = default;
 
 void
@@ -128,3 +156,14 @@ GncDateTime::operator time64() const
 {
     return m_impl->operator time64();
 }
+
+GncDateTime::operator struct tm() const
+{
+    return m_impl->operator struct tm();
+}
+
+long
+GncDateTime::offset() const
+{
+    return m_impl->offset();
+}

src/libqof/qof/gnc-datetime.hpp

@@ -87,10 +87,13 @@ public:
  * @param time: Seconds from the POSIX epoch.
  * @exception std::invalid_argument if the year is outside the constraints.
  */
-    GncDateTime(time64 time);
+    GncDateTime(const time64 time);
+    GncDateTime(const struct tm tm);
     ~GncDateTime();
     void now();
     explicit operator time64() const;
+    explicit operator struct tm() const;
+    long offset() const;
     bool isnull (void) { return m_impl == nullptr; }
 
 private:

src/libqof/qof/test/gtest-gnc-datetime.cpp

@@ -50,3 +50,22 @@ TEST(gnc_datetime_constructors, test_time64_constructor)
     EXPECT_EQ(static_cast<time64>(atime), time);
 }
 
+TEST(gnc_datetime_constructors, test_struct_tm_constructor)
+{
+#ifdef HAVE_STRUCT_TM_GMTOFF
+    const struct tm tm {0, 0, 12, 13, 10, 145, 0, 0, 0, NULL, 0 };
+#else
+    const struct tm tm {0, 0, 12, 13, 10, 145, 0, 0, 0 };
+#endif
+
+    const time64 time = 2394187200; //2045-11-13 12:00:00 Z
+    GncDateTime atime(tm);
+    EXPECT_EQ(static_cast<time64>(atime), time);
+    const struct tm tm1 = static_cast<struct tm>(atime);
+    EXPECT_EQ(tm1.tm_year, tm.tm_year);
+    EXPECT_EQ(tm1.tm_mon, tm.tm_mon);
+    EXPECT_EQ(tm1.tm_mday, tm.tm_mday);
+// We have to contort this a bit to handle offsets > 12, e.g. New Zealand during DST.
+    EXPECT_EQ((24 + tm1.tm_hour - atime.offset() / 3600) % 24, tm.tm_hour);
+    EXPECT_EQ(tm1.tm_min, tm.tm_min);
+}