whytofly
/
qt6-bb10
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Optimize QVector::mid 

Change-Id: Iff7d9ec85a095c6712e6045e7708bb88eac629e1
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
bb10
Jędrzej Nowacki 2014-02-19 11:27:50 +01:00 committed by The Qt Project
parent 7c17b0ad2b
commit 39efc7c3e3
2 changed files with 9 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
src/corelib/tools/qvector.h
View File

@ -833,11 +833,13 @@ Q_OUTOFLINE_TEMPLATE QVector<T> QVector<T>::mid(int pos, int len) const
break;
}
QVector<T> copy;
copy.reserve(len);
for (int i = pos; i < pos + len; ++i)
copy += at(i);
return copy;
QVector<T> midResult;
midResult.reallocData(0, len);
T *srcFrom = d->begin() + pos;
T *srcTo = d->begin() + pos + len;
midResult.copyConstruct(srcFrom, srcTo, midResult.data());
midResult.d->size = len;
return midResult;
}
template <typename T>

2
tests/auto/corelib/tools/qvector/tst_qvector.cpp
View File

@ -1379,6 +1379,8 @@ void tst_QVector::mid() const
list << "foo" << "bar" << "baz" << "bak" << "buck" << "hello" << "kitty";
QCOMPARE(list.mid(3, 3), QVector<QString>() << "bak" << "buck" << "hello");
QCOMPARE(list.mid(6, 10), QVector<QString>() << "kitty");
QCOMPARE(list.mid(-1, 20), list);
QCOMPARE(list.mid(4), QVector<QString>() << "buck" << "hello" << "kitty");
}