General integer-types.

[Shark8 <onewingedshark@gmail.com>]

I'm toying with the idea of making a SWF-player (I found the documentation for the format online) and was wondering about the integers. Sure I could write out all of them (8-bit, 16-bit, 32-bit)x(signed, unsigned) + 64-bit unsigned  = 7-types -- not too bad, but this is a lot of repetition so could I make a generic to qualify?

    Generic
	Size : Positive;
    Package SWF_Integer is
	Exp : Constant Positive := Size-1;
	
	-- For some reason adding the "New Long_Long_Integer" allows
	-- this to compile... but it might ignore the Size aspect.
	Type Signed is New Long_Long_Integer Range -2**Exp..2**Exp-1
	with Size => Size;
        
        -- This doesn't work at all; Size is not static.	
	Type Unsigned is Mod 0..2**Size
	with Size => Size;
	
    End SWF_Integer;

The specs are as follows:
> Integer types and byte order
> The SWF file format uses 8-bit, 16-bit, 32-bit, 64-bit, signed, 
> and unsigned integer types. All integer values are stored in the
> SWF file by using little-endian byte order: the least
> significant byte is stored first, and the most significant byte
> is stored last, in the same way as the Intel x86 architecture.
> The bit order within bytes in the SWF file format is big-endian:
> the most significant bit is stored first, and the least
> significant bit is stored last.
> 
> All integer types must be byte-aligned. That is, the first bit
> of an integer value must be stored in the first bit of a byte in
> the SWF file.

Would the bit_order definition work on ensuring the correct representation? The documentation seems to indicate it is for the bit-numbering in record-representations. Further, would the alignment definition (alignment => 1? 8?) be appropriate?