[swift-users] Data(bytesNoCopy:count:deallocator)

[Andrew Trick]

> On Aug 23, 2016, at 8:40 AM, Stéphane Lizeray via swift-users <swift-users at swift.org> wrote:
> 
> Hello,
> 
> I create an UsafeMutableRawPointer using the allocate method.
> 
> Later on I want to create a Data struct from this pointer using the bytesNoCopy initializer. Which deallocator should I pass?
> 
> It looks like this:
> 
> let retPointer = UnsafeMutableRawPointer.allocate(bytes: size, alignedTo: MemoryLayout<UInt8>.alignment)
> ….
> 
> let d = Data(bytesNoCopy: retPointer, count: size,deallocator:Deallocator.free)

Hi Stéphane,

This should work:

let retPointer = UnsafeMutableRawPointer.allocate(bytes: size, alignedTo: MemoryLayout<UInt8>.alignment)

let d = Data(bytesNoCopy: retPointer, count: size, deallocator: .custom({ (ptr, size) in
      ptr.deallocate(bytes: size, alignedTo: 1)
    }))

-Andy

> 
> Thanks,
> 
> Stéphane
> 
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