AMiRo-OS

/'

µRtWare is a lightweight publish/subscribe middleware for real-time

applications. It was developed as part of the software habitat for the

Autonomous Mini Robot [1] (AMiRo) but can be used for other purposes as well.

Copyright (C) 2018..2020  Thomas Schöpping et al.

This program is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation, either version 3 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program.  If not, see <http://www.gnu.org/licenses/>.

'/

/'### INTRO ##################################################################'/

@startuml

title **µRtWare**\nurtServiceDispatch()\n

/'### PARAMETERS & RETURN ####################################################'/

note

  -- **service** : urt_service_t* --

  The service to dispatch a request for.

  Must not be ""NULL"".

  -- **payload** : void* --

  Pointer where to store the payload (if any).

  May be ""NULL"" if the service expects no payload.

  -- **bytes** : size_t --

  Size of the payload in bytes.

  Must be 0 if the service expects no payload.

  ====

  -- **return** : urt_baserequest_t* --

  Pointer to the request to be processed next.

  May be ""NULL"" if there are no pending requests.

endnote

/'### PROCEDURE ##############################################################'/

start

:lock service;

if (Request list empty?) then (no)

  :access first request (""requestQueue_front"");

  note

    No need to lock the request because it is enqueued at this point.

    Enqueued requests must not be altered without the according service to be locked.

    Since the service has been locked, no enqueued requests will be modified externally.

  endnote

  :proceed ""requestQueue_front"" pointer;

  fork

    if (This was the last request (pointer became ""NULL"")?) then (yes)

      :set ""requestQueue_back"" to ""NULL"";

    else (no)

      :set request ""next"" pointer to ""NULL"";

    endif

  fork again

    if (This was the last HRT request?) then (yes)

      :set ""requestQueue_hrtBack"" to ""NULL"";

    elseif (This was the last FRT/SRT request?) then (yes)

      :set ""requestQueue_fsrtBack"" to ""NULL"";

    else (no)

    endif

  fork again

    :copy payload from request to argument;

  endfork

  :unlock service;

  stop

  note

    Returns pointer to the dispatched request.

  endnote

else (yes)

endif

:unlock service;

stop

note

  Returns ""NULL"".

endnote

/'### OUTRO ##################################################################'/

@enduml