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From: "Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: Performance of the Streams 'Read and 'Write
Date: Fri, 30 Oct 2009 12:12:18 -0700
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Date: 2009-10-30T12:12:18-07:00
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Gautier write-only wrote:
> On 30 Okt., 01:39, "Jeffrey R. Carter"
> <spam.jrcarter....@spam.acm.org> wrote:
> 
>> And if you overlay the Stream_Element_Array onto the Buffer, thus eliminating
>> the copying and the stream attribute operations?
> 
> With an Unchecked_conversion ?

No, that still does a copy.

Type Buffer, as a simple array of bytes, should have Buffer'Component_Size = 
Unsigned_8'Size by default; but you can specify it if you're paranoid. If you're 
really paranoid, you can add a test that Unsigned_8'Size = Stream_Element'Size, 
which you seem to be assuming. Then

procedure Put (B : in Buffer) is -- Terrible naming scheme.
    subtype Buffer_Stream is Stream_Element_Array (1 .. B'Length);

    S : Buffer_Stream;
    for S'Address use B'Address;
    pragma Import (Ada, S);
begin -- Put
    Write (S);
end Put;

-- 
Jeff Carter
"I spun around, and there I was, face to face with a
six-year-old kid. Well, I just threw my guns down and
walked away. Little bastard shot me in the ass."
Blazing Saddles
40