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/'
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µRtWare is a lightweight publish/subscribe middleware for real-time
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applications. It was developed as part of the software habitat for the
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Autonomous Mini Robot [1] (AMiRo) but can be used for other purposes as well.
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Copyright (C) 2018..2020  Thomas Schöpping et al.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program.  If not, see <http://www.gnu.org/licenses/>.
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'/
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/'### INTRO ##################################################################'/
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@startuml
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title **µRtWare**\nurtSrtSubscriberSubscribe()\n
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!include ../../functions.iuml
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/'### PARAMETERS & RETURN ####################################################'/
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note
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  -- **subscriber** : urt_srtsubscriber_t* --
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  The SRT subscriber which shall subscribe to a topic.
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  Must not be ""NULL"".
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  -- **topic** : urt_topic_t* --
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  The topic to subscribe to.
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  Must not be ""NULL"".
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  -- **messages** : urt_message_t* --
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  ""NULL"" terminated list of messages to contribute to the topic.
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  Messages must not be associated to another topic.
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  Once a message has been contributed, it cannot be removed later.
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  May be ""NULL"" (no messages to contribute).
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  -- **usefulnesscb** : urt_srtusefulnessfunc_t* --
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  Pointer to a function to calculate usefulness of a message.
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  Must not be ""NULL"".
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  -- **cbparams** : void* --
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  Optional parameters for the usefulness callback.
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  May be ""NULL"" if the callback expects no parameters.
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  ====
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  -- **return** : urt_status_t --
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  Returns ""URT_STATUS_OK"" on success.
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  Returns ""URT_STATUS_SUBSCRIBE_TOPICSET"" if the subscriber is already associated to a topic.
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endnote
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/'### PROCEDURE ##############################################################'/
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start
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if (Is topic already set?) then (yes)
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  stop
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  note
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    Returns ""URT_STATUS_SUBSCRIBE_TOPICSET"".
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  endnote
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else (no)
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  fork
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    :set topic;
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  fork again
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    :initialize callback;
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    note
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      * **usefulnesscb** ← usefulnesscb
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      * **cbparams** ← cbparams
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    endnote
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  fork again
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    #EEEEEE:initialize members;
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    note #EEEEEE
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      -- urt_basesubscriber_t --
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      .. URT_CFG_PUBSUB_PROFILING == true ..
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      * **sumLatencies** ← 0
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      * **numMessagesReceived** ← 0
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      -- urt_srtsubscriber_t --
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      .. URT_CFG_PUBSUB_PROFILING == true ..
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      * **minLatency** ← ""URT_DELAY_INFINITE""
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      * **maxLatency** ← ""URT_DELAY_IMMEDIATE""
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    endnote
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  endfork
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  :lock topic;
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  fork
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    if (Messages to contribute?) then (yes)
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      $contribute_messages()
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    else (no)
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    endif
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  fork again
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    fork
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      :set message pointer to topic's latest message;
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    fork again
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      :copy timestamp from topic's latest message;
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    endfork
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  fork again
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    :register to topic's event source;
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  fork again
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    #EEEEEE:..//URT_CFG_PUBSUB_PROFILING == true//..\nincrement counter of subscribers (@topic);
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  endfork
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  :unlock topic;
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  stop
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  note
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    Returns ""URT_STATUS_OK"".
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  endnote
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endif
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/'### OUTRO ##################################################################'/
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@enduml