/'
µRT 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 **µRT**\nurtTopicInit()\n

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

note
  -- **topic** : urt_topic_t* --
  The topic to initialize.
  Must not be ""NULL"".
  -- **id** : urt_topicid_t --
  Unique, numeric identifier of the topic.
  ====
  -- **return** : urt_status_t --
  Returns ""URT_STATUS_OK"" on success.
  Returns ""URT_STATUS_TOPIC_DUPLICATE"" if another topic with the same identifier already exists.
endnote

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

start
:initialize members;
note
  * **next** ← ""NULL""
  * **id** ← id
  * urtMutexInit(**lock**)
  * urtEventSourceInit(**evtSource**)
  * **numHrtSubscriber** ← 0
  * urtCondvarInit(**hrtReleased**)
  * urtMessageInit(**mandatoryMessage**)
  * **latestMessage** ← &mandatoryMessage
  .. URT_CFG_PUBSUB_QOS_RATECHECKS == true ..
  * **hrtSubscribers** ← ""NULL""
  * urtTimerInit(**qosRateTimer**)
  .. URT_CFG_PUBSUB_PROFILING == true ..
  * **numMessagesPublished** ← 0
  * **numMessagesDiscarded** ← 0
  * **numSubscribers** ← 0
endnote
:close circular message buffer;
note
  latestMessage""->""next ← latestMessage
endnote
:lock core;
:access first topic;
while (Topic is not ""NULL""\nand topic ID is lower?) is (yes)
  :proceed to next topic;
endwhile (no)
if (Current topic is ""NULL""?) then (yes)
  :append self to core's list of topic;
  :unlock core;
  stop
  note
    Returns ""URT_STATUS_OK"".
  endnote
elseif (Current topic ID is greater?) then (yes)
  :insert self in front of current topic;
  :unlock core;
  stop
  note
    Returns ""URT_STATUS_OK"".
  endnote
else (no)
  :unlock core;
  stop
  note
    Returns ""URT_STATUS_TOPIC_DUPLICATE"".
  endnote
endif

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

@enduml
