The only thing I've though of so far is to declare a class that
holds a bunch of abstract methods, and then have multiple
descendants that each have a special variant of the struct.
And even then I've either got to copy it again, or to cast it
each time I use it. (Though at least with this approach all
the casts are located in one area of the code.)
You don't need to cast it each time, you can do something like:
auto structPointer = cast(MyStruct*) byteArray.ptr;
and use structPointer after that (in D structPointer.foo will get
the member foo, same as (*structPointer).foo). So if you go with
the common parent approach , you can just store that pointer as a
field. This will require one extra pointer dereference each time
you access the struct, though. If you need to access it a lot it
may be more efficient to make a field of type MyStrtuct and just
copy the data to it. The time it takes to copy the struct
shouldn't really be significant anyway, since you are reading it
from a file and file IO is typically much slower than copying
memory.
By the way, if you use the common parent approach, the common
parent should probably be an interface
(http://dlang.org/interface.html), not a class.
