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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Dynamically reallocated buffer
Newsgroups: comp.lang.ada
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Date: Fri, 1 Jun 2007 09:30:04 +0200
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Date: 2007-06-01T09:27:45+02:00
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On Thu, 31 May 2007 23:33:46 -0700, Maciej Sobczak wrote:

> I need a dynamically reallocated buffer of bytes, which I can extend
> at run-time by appending new fragments to the whole buffer. The
> purpose of the buffer is to pass it later to the subprogram that
> writes it "en bloc" to some external device.
> 
> For those of you who know C++ I need something like:
> 
> vector<unsigned char> buffer;
> // fill the buffer with push_back or insert at end
> // ...
> write_to_device(&buffer[0], buffer.size());
> 
> The problem is that Ada.Containers.Vectors does not provide the
> necessary guarantees to be any useful in this context.
> 
> What are your suggestions?

type Device_Buffer is array (Positiver range <>)
   of Interfaces.C.unsigned_char;

The maximal block size is usually known. If not, then device is
stream-oriented and blocks can be safely split into chucks of known size.
In that case Device_Buffer is a segmented buffer. In most cases you don't
need to realloc anything.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de