qvector.cpp

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#include "qvector.h"
#include "qtools_p.h"
#include <string.h>

QT_BEGIN_NAMESPACE

static inline int alignmentThreshold()
{
    // malloc on 32-bit platforms should return pointers that are 8-byte aligned or more
    // while on 64-bit platforms they should be 16-byte aligned or more
    return 2 * sizeof(void*);
}

QVectorData QVectorData::shared_null = { Q_BASIC_ATOMIC_INITIALIZER(1), 0, 0, true, false, 0 };

QVectorData *QVectorData::malloc(int sizeofTypedData, int size, int sizeofT, QVectorData *init)
{
    QVectorData* p = (QVectorData *)qMalloc(sizeofTypedData + (size - 1) * sizeofT);
    Q_CHECK_PTR(p);
    ::memcpy(p, init, sizeofTypedData + (qMin(size, init->alloc) - 1) * sizeofT);
    return p;
}

QVectorData *QVectorData::allocate(int size, int alignment)
{
    return static_cast<QVectorData *>(alignment > alignmentThreshold() ? qMallocAligned(size, alignment) : qMalloc(size));
}

QVectorData *QVectorData::reallocate(QVectorData *x, int newsize, int oldsize, int alignment)
{
    if (alignment > alignmentThreshold())
        return static_cast<QVectorData *>(qReallocAligned(x, newsize, oldsize, alignment));
    return static_cast<QVectorData *>(qRealloc(x, newsize));
}

void QVectorData::free(QVectorData *x, int alignment)
{
    if (alignment > alignmentThreshold())
        qFreeAligned(x);
    else
        qFree(x);
}

int QVectorData::grow(int sizeofTypedData, int size, int sizeofT, bool excessive)
{
    if (excessive)
        return size + size / 2;
    return qAllocMore(size * sizeofT, sizeofTypedData - sizeofT) / sizeofT;
}

QT_END_NAMESPACE