calloc in Swift

Question

How do I transform the following ObjectiveC statements into SWIFT:

UInt32 *pixels;
pixels = (UInt32 *) calloc(height * width, sizeof(UInt32));

Answer 1

If you really know what you are doing and insist in allocating memory unsafely using calloc:

var pixels: UnsafeMutablePointer<UInt32>
pixels = calloc(height * width, sizeof(UInt32))

or just

var pixels = calloc(height * width, sizeof(UInt32))

Answer 2

Here's an easier way of allocating that array in swift:

var pixels = [UInt32](count: height * width, repeatedValue: 0)

If that's what you actually want to do.

But, if you need a pointer from calloc for some reason, go with:

let pixels = calloc(UInt(height * width), UInt(sizeof(UInt32)))

The type of pixels though must be a type of UnsafeMutablePointer<T>, and you would handle it like a swift pointer in the rest of your code.

Answer 3

For Swift-3 : UnsafeMutablePointer is replace by UnsafeMutableRawPointer

 var pixels = UnsafeMutableRawPointer( calloc(height * width, MemoryLayout<UInt32>.size) )

Reference