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

!include ../../functions.iuml

/'### PARAMETERS & START #####################################################'/

start

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.

end note

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

:lock topic;

:access next message;

while (HRT consumers left for the message\nor the message timestamp was modified\nand a timeout occurred?) is (yes)

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

    :iterate to next message;

  else (no)

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

  endif

endwhile (no)

if (Timeout occurred?) then (yes)

  :unlock topic;

  :return ""URT_STATUS_ERROR"";

else (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;

  :return ""URT_STATUS_OK"";

endif

/'### STOP & RETURN ##########################################################'/

stop

note

  -- **return** ""urt_status_t"" --

  Returns ""URT_STATUS_ERROR"" on timeout.

end note

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

@enduml