Hi,
I have some issues using the new raw memory API. For instance, let's
suppose I want to call the `SecRandomCopyBytes` API to generate a
cryptographically secure random 32-bit number. The difficulty is its 3rd
argument, which is declared as UnsafeMutablePointer<UInt8>. Here is a
function that does that:
func entropicRandom() -> UInt32 {
let randomWordPT = UnsafeMutablePointer<UInt32>.allocate(capacity: 1)
let _ = randomWordPT.withMemoryRebound(to: UInt8.self, capacity: 4) {
(p: UnsafeMutablePointer<UInt8>) -> Int32 in
let result = SecRandomCopyBytes(kSecRandomDefault, MemoryLayout<
UInt32>.size, p)
return result
}
let randomInt32 = randomWordPT[0]
randomWordPT.deallocate(capacity: 1)
return randomInt32
}
apparently, the calls to allocate and then deallocate suggest that there is
some heap allocation happening behind the scene here, possibly malloc/free.
Is that correct?
If so, this is quite wasteful. Is there a way to use a local variable on
the stack to achieve the same result?
Thanks,
Jean-Denis
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