C++ (Cpp) QVector::capacity Examples

Example #1

void tst_QVector::outOfMemory()
{
    fooCtor = 0;
    fooDtor = 0;

    const int N = 0x7fffffff / sizeof(Foo);

    {
        QVector<Foo> a;

        QSKIP("This test crashes on many of our machines.", SkipSingle);
        a.resize(N);
        if (a.size() == N) {
            QVERIFY(a.capacity() >= N);
            QCOMPARE(fooCtor, N);
            QCOMPARE(fooDtor, 0);

            for (int i = 0; i < N; i += 35000)
                a[i] = Foo();
        } else {
            // this is the case we're actually testing
            QCOMPARE(a.size(), 0);
            QCOMPARE(a.capacity(), 0);
            QCOMPARE(fooCtor, 0);
            QCOMPARE(fooDtor, 0);

            a.resize(5);
            QCOMPARE(a.size(), 5);
            QVERIFY(a.capacity() >= 5);
            QCOMPARE(fooCtor, 5);
            QCOMPARE(fooDtor, 0);

            const int Prealloc = a.capacity();
            a.resize(Prealloc + 1);
            QCOMPARE(a.size(), Prealloc + 1);
            QVERIFY(a.capacity() >= Prealloc + 1);
            QCOMPARE(fooCtor, Prealloc + 6);
            QCOMPARE(fooDtor, 5);

            a.resize(0x10000000);
            QCOMPARE(a.size(), 0);
            QCOMPARE(a.capacity(), 0);
            QCOMPARE(fooCtor, Prealloc + 6);
            QCOMPARE(fooDtor, Prealloc + 6);
        }
    }

    fooCtor = 0;
    fooDtor = 0;

    {
        QVector<Foo> a(N);
        if (a.size() == N) {
            QVERIFY(a.capacity() >= N);
            QCOMPARE(fooCtor, N);
            QCOMPARE(fooDtor, 0);

            for (int i = 0; i < N; i += 35000)
                a[i] = Foo();
        } else {
            // this is the case we're actually testing
            QCOMPARE(a.size(), 0);
            QCOMPARE(a.capacity(), 0);
            QCOMPARE(fooCtor, 0);
            QCOMPARE(fooDtor, 0);
        }
    }

    Foo foo;

    fooCtor = 0;
    fooDtor = 0;

    {
        QVector<Foo> a(N, foo);
        if (a.size() == N) {
            QVERIFY(a.capacity() >= N);
            QCOMPARE(fooCtor, N);
            QCOMPARE(fooDtor, 0);

            for (int i = 0; i < N; i += 35000)
                a[i] = Foo();
        } else {
            // this is the case we're actually testing
            QCOMPARE(a.size(), 0);
            QCOMPARE(a.capacity(), 0);
            QCOMPARE(fooCtor, 0);
            QCOMPARE(fooDtor, 0);
        }
    }

    fooCtor = 0;
    fooDtor = 0;

    {
        QVector<Foo> a;
        a.resize(10);
        QCOMPARE(fooCtor, 10);
        QCOMPARE(fooDtor, 0);

        QVector<Foo> b(a);
        QCOMPARE(fooCtor, 10);
        QCOMPARE(fooDtor, 0);

        a.resize(N);
        if (a.size() == N) {
            QCOMPARE(fooCtor, N + 10);
        } else {
            QCOMPARE(a.size(), 0);
            QCOMPARE(a.capacity(), 0);
            QCOMPARE(fooCtor, 10);
            QCOMPARE(fooDtor, 0);

            QCOMPARE(b.size(), 10);
            QVERIFY(b.capacity() >= 10);
        }
    }

    {
        QVector<int> a;
        a.resize(10);

        QVector<int> b(a);

        a.resize(N);
        if (a.size() == N) {
            for (int i = 0; i < N; i += 60000)
                a[i] = i;
        } else {
            QCOMPARE(a.size(), 0);
            QCOMPARE(a.capacity(), 0);

            QCOMPARE(b.size(), 10);
            QVERIFY(b.capacity() >= 10);
        }

        b.resize(N - 1);
        if (b.size() == N - 1) {
            for (int i = 0; i < N - 1; i += 60000)
                b[i] = i;
        } else {
            QCOMPARE(b.size(), 0);
            QCOMPARE(b.capacity(), 0);
        }
    }
}