Rework an assertion to eliminate a common sub-expression using a lambda

This take more lines but makes the condition clearer and the lines
shorter, even after converting to use the names for constants in the
condition.

Change-Id: I9e5b7b79ff62095ed11b8723be238444fd32d9c1
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 9 insertions, 8 deletions

diff --git a/src/corelib/time/qdatetime.cpp b/src/corelib/time/qdatetime.cpp
index 9e9f0912a1..6818837e8c 100644
--- a/src/corelib/time/qdatetime.cpp
+++ b/src/corelib/time/qdatetime.cpp
@@ -3203,14 +3203,15 @@ inline qint64 QDateTimePrivate::zoneMSecsToEpochMSecs(qint64 zoneMSecs, const QT
     // Get the effective data from QTimeZone
     QTimeZonePrivate::Data data = zone.d->dataForLocalTime(zoneMSecs, int(hint));
     Q_ASSERT(zone.d->offsetFromUtc(data.atMSecsSinceEpoch) == data.offsetFromUtc);
-    Q_ASSERT((zoneMSecs - data.atMSecsSinceEpoch) / 1000 == data.offsetFromUtc
-             // If zoneMSecs fell in a spring-forward's gap, we get this instead:
-             || (zoneMSecs - data.atMSecsSinceEpoch) / 1000 == data.standardTimeOffset
-             // If we have a second DST, like in Europe/Berlin 1947 (mid-summer time).
-             // If zoneMSecs fell in a gap at beginning of mid-summer time, we get this instead:
-             || (zoneMSecs - data.atMSecsSinceEpoch) / 1000 == 2 * data.standardTimeOffset
-             // If it fell in a skipped day (Pacific date-line crossings), this happens:
-             || (data.offsetFromUtc - (zoneMSecs - data.atMSecsSinceEpoch) / 1000) % 86400 == 0);
+    Q_ASSERT(([data](qint64 offset) {
+                return offset == data.offsetFromUtc
+                    // When zoneMSecs falls in a spring-forward's gap:
+                    || offset == data.standardTimeOffset
+                    // When it falls in the gap leading into double-DST:
+                    || offset == 2 * data.standardTimeOffset
+                    // When it falls in a skipped day (Pacific date-line crossings):
+                    || (data.offsetFromUtc - offset) % SECS_PER_DAY == 0;
+                    })((zoneMSecs - data.atMSecsSinceEpoch) / MSECS_PER_SEC));
     // Docs state any time before 1970-01-01 will *not* have any DST applied
     // but all affected times afterwards will have DST applied.
     if (data.atMSecsSinceEpoch < 0) {