MIDIPacketNext UB: Accessing Fields of Unaligned Struct
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The Problem
As listed in the RFC for raw references it is:
...essentially impossible to create a raw pointer pointing to an unaligned struct field: &packed.field as *const _ creates an intermediate unaligned reference, triggering undefined behavior because it is not aligned.
Assuming that MIDIPackets could be unaligned as discussed in #10, then our accessing the .length field triggers this UB.
Potential Fixes
The most direct route would be to copy the MIDIPacket (or part of it) to the stack, where reading its fields is not UB (see the very bottom of this section). I don't know if this is feasible because of the flexible-array-member .data field.
So it seems to me that this likely depends on #10 being fixed first. We need some way to refer to MIDIPacket before we can access its fields.
If we can get a raw pointer to the .length field, it seems like we might be able to read it using std::ptr::read_unaligned().