qtools_p.h File Reference

#include "QtCore/qglobal.h"

Go to the source code of this file.

Functions
int Q_CORE_EXPORT	qAllocMore (int alloc, int extra)

Function Documentation

qAllocMore()

int Q_CORE_EXPORT qAllocMore	(	int	alloc,
		int	extra
	)

Definition at line 70 of file qbytearray.cpp.

Referenced by QByteArray::append(), QFragmentMapData< QTextBlockData >::createFragment(), grow(), QVectorData::grow(), QString::grow(), and QByteArray::prepend().

{
    Q_ASSERT(alloc >= 0 && extra >= 0);
    Q_ASSERT_X(alloc < (1 << 30) - extra, "qAllocMore", "Requested size is too large!");

    if (alloc == 0 && extra == 0)
        return 0;
    const int page = 1 << 12;
    int nalloc;
    alloc += extra;
    if (alloc < 1<<6) {
        nalloc = (1<<3) + ((alloc >>3) << 3);
    } else  {
        // don't do anything if the loop will overflow signed int.
        if (alloc >= INT_MAX/2)
            return INT_MAX;
        nalloc = (alloc < page) ? 1 << 3 : page;
        while (nalloc < alloc) {
            if (nalloc <= 0)
                return INT_MAX;
            nalloc *= 2;
        }
    }
    return nalloc - extra;
}