> On Jun 26, 2017, at 12:00 AM, Roderick Mann via swift-users
> <swift-users@swift.org> wrote:
>
> I mean, it's as straightforward as my example. I have a Data of arbitrary
> size (anywhere from 3 to 29 bytes, let's say). The last two bytes form a
> UInt16 CRC. I need to get those last two out and compare them against the CRC
> I compute for the rest of the bytes.
>
> Having said that, I just used withUnsafeBytes() and grabbed the last two
> bytes, and assembled them into a UInt16 with shift and or.
>
> I'd like to be able to do something like value<Double>(at: 3), though.
You kinda can, although it’s a bit more verbose:
let crc = myData[(myData.endIndex - 2)…].withUnsafeBytes { UInt16(littleEndian:
$0.pointee) }
If you look at the source, withUnsafeBytes calls withMemoryRebound with the
inferred generic type (UInt16 in this case), so I think this should be safe.
Charles
_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users
