02.05.2016, 10:44, "Thiago Macieira" <[email protected]>: > Hello > > https://codereview.qt-project.org/157714 > > I've just pushed one large commit that changes QDateTime to support a "short > QDateTime Optimisation". Inspired by the SSO mechanism used in libc++ and > similar to what we've done to QVersionNumber, I've made QDateTime not allocate > memory for most uses (local time or UTC, within 2 million years of 1970). > > The optimisation is only for 64-bit systems, since QDateTime simply wasn't > wide enough to accommodate the data. 32 bits isn't enough for storing seconds > since 1970, much less milliseconds and the extra information we needed. But on > 64-bit systems, the pointer is split in two: 8 bits for status flags > (including > the LSB indicating it's a short QDateTime) and 56 bits for the millisecond > count. > > The commit is quite large. I will spend some time during the next week seeing > if I can split it up into bite-sized chunks. > > Meanwhile, I'd like to ask for help testing this. Since I've dropped the use > of QSharedDataPointer, I might have introduced sharing issues. And I'd really > like someone to run the unit tests on a big-endian system.
Do you mean 64-bit big-endian system, or both 32-bit and 64-bit? > > -- > Thiago Macieira - thiago.macieira (AT) intel.com > Software Architect - Intel Open Source Technology Center > > _______________________________________________ > Development mailing list > [email protected] > http://lists.qt-project.org/mailman/listinfo/development -- Regards, Konstantin _______________________________________________ Development mailing list [email protected] http://lists.qt-project.org/mailman/listinfo/development
