A little trouble with very large arrays.

[Shark8 <onewingedshark@gmail.com>]

I'm trying to implement a FITS library for work -- see https://fits.gsfc.nasa.gov/standard40/fits_standard40aa.pdf -- and have come across some rather interesting problems implementing it.

The main-problem right now is the "Primary Data Array" which can have a dimensionality in 1..999, each itself with some non-zero range. (In the files these are specified by keywords in the file like NAXIS = n, NAXIS1 = n_1, NAXIS2 = n_2, and so on until the NAXISn = n_n keyword/value pair is encountered.)

Relatively straightforward, no? Well, I'd thought I could handle everything with a dimensionality-array and generic like:


    Type Axis_Count is range 0..999 with Size => 10;
    Type Axis_Dimensions is Array (Axis_Count range <>) of Positive
      with Default_Component_Value => 1;
...
Generic
	Type Element is (<>);
	Dim : Axis_Dimensions:= (1..999 => 1);
Package FITS.Data with Pure is

	Type Data_Array is not null access Array(
			1..Dim( 1),1..Dim( 2),1..Dim( 3),1..Dim( 4),
  			1..Dim( 5),1..Dim( 6),1..Dim( 7),1..Dim( 8),
  			--...
			1..Dim( 997),1..Dim( 998),1..Dim( 999)
		) of Element
      with Convention => Fortran;
End FITS.Data;

But no dice.
GNAT won't even compile an array like this [999 indexes].


What's the proper way to go about doing this?
(As another interesting constraint, the file-format mandates a sort of block-structure of 2880 bytes [23040 bits], and while I don't anticipate this being an issue, something that might be relevant.)