QByteArray throws bad allocation exception during prepend/append process.

QByteArray small;
small.resize(1024);
small.fill('s', 1024);

QByteArray big;
big.resize(1024*1024*1024);
big.fill('b');

//The below lines will not work.
big.append(small); //big += small;
small.append(big); //small += big; //big.prepend(small);

const int HALF_INT_MAX = INT_MAX / 2;
int combinedByteArraysSize = big.size() + small.size();
#if 1
    if(combinedByteArraysSize > HALF_INT_MAX && combinedByteArraysSize < INT_MAX) {
        big.reserve(combinedByteArraysSize);
        big.append(small); //big += small;
    }
#else //Below lines does not work on Windows system, but work on OS X system.
    if(combinedByteArraysSize > HALF_INT_MAX && combinedByteArraysSize < INT_MAX) {
        small.reserve(combinedByteArraysSize);
        small.append(big); //small += big; //big.prepend(small);
    }
#endif