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swiftunsafemutablepointer

In Swift 3.1, UnsafeMutablePointer.initialize(from:) is deprecated

In Swift 3.1, UnsafeMutablePointer.initialize(from:) is deprecated. Xcode suggests I use UnsafeMutableBufferPointer.initialize(from:) instead. I have a code block that looks like this:

let pointer = UnsafeMutablePointer<UInt8>.allocate(capacity: 64)
pointer.initialize(from: repeatElement(0, count: 64))

The code gives me a compile time warning because of the deprecation. So I'm going to change that to:

let pointer = UnsafeMutablePointer<UInt8>.allocate(capacity: 64)
let buffer = UnsafeMutableBufferPointer(start: pointer, count: 64)
_ = buffer.initialize(from: repeatElement(0, count: 64))

Is this the right way to do this? I just wanted to make sure that I'm doing it correctly.

Solution

  • It is correct, but you can allocate and initialize memory slightly simpler with

    let pointer = UnsafeMutablePointer<UInt8>.allocate(capacity: 64)
pointer.initialize(to: 0, count: 64)

    Creating a buffer pointer view can still be useful because that is a collection, has a count property and can be enumerated:

    let buffer = UnsafeMutableBufferPointer(start: pointer, count: 64)

for byte in buffer {
    // ...
}

    but that is independent of how the memory is initialized.