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From: Ludovic Brenta <ludovic@ludovic-brenta.org>
Newsgroups: comp.lang.ada
Subject: Re: Load an object from a file
Date: Sun, 19 Apr 2009 12:52:33 -0700 (PDT)
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Date: 2009-04-19T12:52:33-07:00
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Olivier Scalbert wrote on comp.lang.ada:
> I have an endianness problem. In the file, The u2 data are stored in
> big-endian order. As I am working on a Pentium, the reading is done in
> little-endian order. Is it possible to fix it with the representation
> stuff ?

No; Ada's representation clauses only allow you to control bit order,
not
byte order.  On little-endian architectures, you'll have to resort to
something like

procedure Read (Stream : access Ada.Streams.Root_Stream_Type'Class;
                Item : out u2) is
   type Byte is mod 2**8;
   for Byte'Size use 8;
   High_Order, Low_Order : Byte;
begin
   Byte'Read (Stream, High_Order); -- call the predefined Read for
type Byte
   Byte'Read (Stream, Low_Order);
   Item := High_Order * 2**8 + Low_Order;
end Read;

for u2'Read use Read;

HTH

--
Ludovic Brenta.