Re: Stream_Element_Array

[Alexander Korolev <antonovkablog@gmail.com>]

On Sep 15, 12:13 am, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:
> On Wed, 14 Sep 2011 10:16:09 -0700 (PDT), Alexander Korolev wrote:
> > I've been advised and that worked out for many in few cases to use
> > Volatile_Streams.Memory_Resident_Stream.
>
> This is not what you need. It is a stream backed by the memory. I also
> implemented such, backed by a String object, that is when you write, you do
> into the string, when you read then from the string.
>
> In your case the other end is not the memory but the wire. This is what
> Serial_Port of GNAT.Serial_Communications is, an implementation of stream.
>
> So you simply derive or aggregate a new type from/into it, place there an
> output buffer of Stream_Element_Array of the maximal message size, and
> Stream_Element_Array for the input, usually just one element length.
>
> The pattern is:
>
>    Root_Stream_Type -- abstract stream
>      |
>    Serial_Port -- concrete stream, transport layer
>      |
>    your type -- specific protocol implementation
>
> --
> Regards,
> Dmitry A. Kazakovhttp://www.dmitry-kazakov.de

"It is a stream backed by the memory"
yes

"In your case the other end is not the memory but the wire"
I am not sure I undestand you complitly. What's wrong, at least for
now, to build \ construct in memory the Buffer (Stream_Element_Array)
with full command (according the format I posted) inside and after
that send it over any stream (including GNAT.Serial, Socket etc)
derived from Root_Stream_Type. Basicly, I don't need even a Type -
I am using it just get Unsigned_16 serialized into Stream Elements.
That's it. It's kind of hadcrafting. I also can override My_Type'Write
attribute and send to Serial port ... Your approach is to create a new
stream actully, which will take into account the PROTOCOL specifics.
Absolutly agree with that. But what is wrong with manual approach I am
implementing.