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**\nurtPublisherPublish()\n

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

note

  -- **publisher** : urt_publisher_t* --

  Pointer to the publisher to use.

  Must not be ""NULL"".

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

  Pointer to the data to be published.

  May be ""NULL"" for messages without payload.

  -- **n** : size_t --

  Size of the payload in bytes.

  -- **t** : urt_osTime_t --

  Timestamp to be set for the message.

  -- **timeout** : urt_delay_t --

  Timeout delay in case the message cannot be published.

  ====

  -- **return** : urt_status_t --

  Returns ""URT_STATUS_OK"" on success.

  Returns ""URT_STATUS_ERROR"" on timeout.

endnote

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

start

:lock topic;

:access topic's next message;

while (HRT consumers left for the message?) is (yes)

  :wait for topic's condition variable (using topic's mutex) to be signaled or timeout;

  if (Timeout occurred?) then (yes)

    :unlock topic;

    stop

    note

      Returns ""URT_STATUS_ERROR"".

    endnote

  else (no)

    if (Message timestamp was modified?) then (yes)

      :access topic's next message;

    else (no)

    endif

  endif

endwhile (no)

fork

  fork

    :iterate topic pointer to this message;

  fork again

    :copy payload to message;

  fork again

    :set origin time of message;

  fork again

    :set number of HRT consumers (from topic);

  endfork

fork again

  :set QoS rate timer (@topic) wrt. most critical HRT subscriber;

fork again

  while (HRT subscribers left?) is (yes)

    if (QoS delay timer (@subscriber) is not armed?) then (yes)

      :set QoS delay timer (@subscriber) wrt. origin time of the message;

      note: No lock required since this timer is only accessed when the topic is locked.

    else (no)

    endif

    :iterate to next HRT subscriber;

  endwhile (no)

endfork

:fire event;

note: Msut be within topic lock because of HRT counter.

:unlock topic;

stop

note

 Returns ""URT_STATUS_OK"".

endnote

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

@enduml