summaryrefslogtreecommitdiffstats
path: root/src/corelib/tools
diff options
context:
space:
mode:
authorEdward Welbourne <edward.welbourne@qt.io>2017-11-07 17:17:59 +0100
committerEdward Welbourne <edward.welbourne@qt.io>2017-11-30 20:20:10 +0000
commit35176c22896a6c633408907e8113c3f1b9a846b0 (patch)
treeb24d177879be03b07246feb7d5c9208b651883e9 /src/corelib/tools
parent68bcccac228b73c54137304718c3c92460bc1f4b (diff)
Avoid underflow on arithmetic with possibly-first transition times
A transition time may represent the beginning of time; as such, arithmetic on it might underflow, e.g. on adding a negative zone offset to compare with a given time. So move the arithmetic to the other side of the comparison in such cases. Change-Id: I1697a03ebf74679ff86059664dd2b173b9c4c367 Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'src/corelib/tools')
-rw-r--r--src/corelib/tools/qtimezoneprivate.cpp4
1 files changed, 2 insertions, 2 deletions
diff --git a/src/corelib/tools/qtimezoneprivate.cpp b/src/corelib/tools/qtimezoneprivate.cpp
index e45dd48de0..1a5135f103 100644
--- a/src/corelib/tools/qtimezoneprivate.cpp
+++ b/src/corelib/tools/qtimezoneprivate.cpp
@@ -329,7 +329,7 @@ QTimeZonePrivate::Data QTimeZonePrivate::dataForLocalTime(qint64 forLocalMSecs,
// Only around the transition times might we need another.
Data tran = previousTransition(forLocalMSecs - sixteenHoursInMSecs);
Q_ASSERT(forLocalMSecs < 0 || // Pre-epoch TZ info may be unavailable
- forLocalMSecs >= tran.atMSecsSinceEpoch + tran.offsetFromUtc * 1000);
+ forLocalMSecs - tran.offsetFromUtc * 1000 >= tran.atMSecsSinceEpoch);
Data nextTran = nextTransition(tran.atMSecsSinceEpoch);
/*
Now walk those forward until they bracket forLocalMSecs with transitions.
@@ -363,7 +363,7 @@ QTimeZonePrivate::Data QTimeZonePrivate::dataForLocalTime(qint64 forLocalMSecs,
fail life's tricky.
*/
Q_ASSERT(forLocalMSecs < 0
- || forLocalMSecs > tran.atMSecsSinceEpoch + tran.offsetFromUtc * 1000);
+ || forLocalMSecs - tran.offsetFromUtc * 1000 > tran.atMSecsSinceEpoch);
const qint64 nextStart = nextTran.atMSecsSinceEpoch;
// Work out the UTC values it might make sense to return:
nextTran.atMSecsSinceEpoch = forLocalMSecs - nextTran.offsetFromUtc * 1000;