It's undefined behaviour. It might work, either by design or accident, or it could be really slow or stop working in the next OS update or hardware revision. Just avoid it.
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if it works by design it's quite pity to see the man-years(?) of hardware designers cumulative time wasted for a feature that they considered needed and that we end up not using, because it might not work in the future!
UnsafeMutableRawPointer.copyMemory(from:byteCount:) simply forwards its parameters to memmove as (essentially) memmove(baseAddress, from, byteCount).
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Hi Karl,
For the time being I'm not concerned with the data representation of my packet structures. I just need to encode my packets into Data and decode them into the same typealias or struct on the receiving system. I will eventually need to be concerned with the representation, but for now I can assume the receiving system will be of the same type as the sending system. I see some other posts from telecommunication developers trying to use Swift, but they may have match particular data layouts. I only added the "packed" attribute to trade off some CPU time for communication bandwidth. I'm not trying to use unaligned pointers, but I was expecting the Swift compiler to generate bit shifting and masking as the Obj C compiler does. I can build up packets using the data.append and avoid variable length arrays in my structs.
Thanks,
Bob Rice
consider MessagePack or a similar beast. it's like JSON, but binary, smaller and quicker.
The only difference is that copyMemory allows overlapping memory regions. It has memmove semantics.
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