How do I cast array of unsigned short to an array of int?

Question

I have 2 arrays:

unsigned short* array1;
int* array2;

Is there a quick way to get all the data in array1 into array2 such that the values of array2[0]=array1[0], array2[1] = array1[1] ...etc.

My question mentions casting but I think that's wishful thinking! Obviously I can do this element by element using a for loop but I'm writing an image processing application and speed is key. If not casting then is there any other solution? Thanks.

Answer 1

if (sizeof (int) == sizeof (short)) {
    array2 = (int*)array1; // UB: this may not work on some implementations
} else {
    // allocate memory for array2
    for (i = 0; i < nelems; i++) {
        array2[i] = array1[i];
    }
    // possibly release resources for array1
}

Answer 2

How do I cast array of unsigned short to an array of int?

You don't. If you do, and you use the result, you'll have some nice undefined behavior at hand.

Is there a quick way to get all the data in array1 into array2

Yes, copy the array elements. It will be fast on any decent modern computer.