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From: tmoran@bix.com
Subject: Re: S'Write and How To Count Bytes
Date: 2000/10/02
Message-ID: <878C5.275815$i5.3825407@news1.frmt1.sfba.home.com>#1/1
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Date: 2000-10-02T00:00:00+00:00
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>... I will get out what I expect.
  type Temperature is new Integer range 60 .. 80;
  for Temperature'size use 8; -- or 7
Is a Temperature'Write going to produce one byte, because that's how
big Temperature is, or 4 bytes, because that's how big Integer is?
  type R is record
    Speed : Long_Integer;
  end record;
  for R use record
    S at 0 range 0 .. 7;
  end record;
Will an R'Write produce one byte for S, or 8 or what?

>A perfect solution would be controlled representation of the (tagged)
>record types and a fast overlay of a Stream_Element_Array.
  I remember this discussion, but not the bottom line.  What's wrong
with
  TAG_SIZE : constant := 4;
  ...
  type This_Buffer is new Buffer with record
    Speed : Integer;
    T : Temperature;
  end record;
  for This_Buffer use record
    Speed at TAG_SIZE range 0 .. 7;
    T at Tag_Size+1 range 0 .. 7;
  end record;
and then overlay a Stream_Element_Array?  (Or a
System.Storage_Elements.Storage_Array?)
  I'd rather trust to TAG_SIZE being 4, or at least a single thing to
change, as I move between compilers, rather than trusting Stream stuff.