/'
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**\nurtFrtSubscriberSubscribe()\n

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

note
  -- **subscriber** : urt_frtsubscriber_t* --
  The FRT subscriber which shall subscribe to a topic.
  Must not be ""NULL"".
  -- **topic** : urt_topic_t* --
  The topic to subscribe to.
  Must not be ""NULL"".
  -- **messages** : urt_message_t* --
  ""NULL"" terminated list of messages to contribute to the topic.
  Messages must not be associated to another topic.
  Once a message has been contributed, it cannot be removed later.
  May be ""NULL"" (no messages to contribute).
  -- **deadline** : urt_delay_t --
  Maximum latency to consume messages.
  A value of 0 indicates that latency is of no concern.
  -- **jitter** : urt_delay_t --
  Maximum allowed jitter (difference between maximum and minimum latency) when consuming messages.
  A value of 0 indicates that jitter is of no concern.
  ====
  -- **return** : urt_status_t --
  Returns ""URT_STATUS_OK"" on success.
  Returns ""URT_STATUS_ERROR"" if the subscriber is already associated to a topic.
endnote

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

start
if (Is topic already set?) then (yes)
  stop
  note
    Returns ""URT_STATUS_ERROR"".
  endnote
else (no)
  fork
    :set topic;
  fork again
    :set deadline offset;
  fork again
    :set maximum jitter;
  endfork
  :lock topic;
  fork
    if (Messages to contribute?) then (yes)
      !include ../contributemessages.iuml
    else (no)
    endif
  fork again
    fork
      :set message pointer to topic's latest message;
    fork again
      :copy timestamp from topic's latest message;
    endfork
  fork again
    :register to topic's event source;
  endfork
  :unlock topic;
  stop
  note
    Returns ""URT_STATUS_OK"".
  endnote
endif

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

@enduml
