Re: Newbie question : types , representation

[mcc@entropy.cs.princeton.edu (Martin C. Carlisle)]

You need to be very careful with the below.  This works fine if, like
Cohen, you are ONLY interested in these two representations.  I just
implemented a Base-64 converter this weekend, and I found the bit order
on Win 98 to be frustrating, and GNAT didn't support changing it (or
else I was doing it wrong).  The modular type worked best for me.
Here's what the bits looked like:

yyxxxxxx zzzzyyyy wwwwwwzz

Note the six bits making up y and z aren't even contiguous.

--Martin

In article <XFMail.990822164551.wilhelm.spickermann@t-online.de>,
Wilhelm Spickermann  <wilhelm.spickermann@t-online.de> wrote:
>The second problem may be solveable using the following parts
>(look into Cohen: Ada as a second language, 2nd Ed.; Part 19.4.5
>where he solved the problem of working with Microsofts FAT12 (12 Bit
>numbers in a packed array))
>
>type Char_64_Array is array (Sometype) of Char_64;
>type Packed_Char_64_Array is new Char_64_Array;
>for Packed_Char_64_Array'Component_Size use 6;
>pragma Pack (Packed_Char_64_Array);
-- 
Martin C. Carlisle, Asst Prof of Computer Science, US Air Force Academy
carlislem@acm.org, http://www.usafa.af.mil/dfcs/bios/carlisle.html
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