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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**\nPublish-Subscribe System
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!include ./functions.iuml
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/'### ENTITIES ###############################################################'/
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!startsub ENTITIES
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/' Message type. '/
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$structure("urt_message_t") {
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    'Pointer to the next message in a list.
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  + {field} next : urt_message_t*
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    'Pointer to some arbitrary (reusable) payload object.
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  + {field} payload : void*
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    'Origin time of the message.
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  + {field} originTime : urt_osTime_t
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    'Counter of HRT subscribers that did not consume the message yet.
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  + {field} numHrtConsumersLeft : unsigned int
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  .. URT_CFG_PUBSUB_PROFILING == true ..
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    'Counter of overall subscribers that did not consume the message yet.
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  + {field} numConsumersLeft : unsigned int
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  __
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    'Initializes a urt_message_t object.
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  + {method} urtMessageInit (message : urt_message_t*, payload : void*) : void
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}
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$group("subscriber") {
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  /' Base subscriber type. '/
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  $structure("urt_basesubscriber_t") {
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      'Pointer to the topic, this subscriber subscribed to.
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    + {field} topic : urt_topic_t*
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      'Event listener to notify the node about new messages.
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    + {field} evtListener : urt_osEventListener_t
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      'Pointer to the message consumed most recently.
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    + {field} lastMessage : urt_message_t*
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      'Copy of the origin time of the message consumed most recently.
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    + {field} lastMessageTime : urt_osTime_t
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    .. URT_CFG_PUBSUB_PROFILING == true ..
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      'Sum of all latencies.
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    + {field} sumLatencies : uint64_t
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      'Number of messages received.
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    + {field} numMessagesReceived : uint64_t
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  }
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  /' NRT subscriber type. '/
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  $structure("urt_nrtsubscriber_t") {
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    .. URT_CFG_PUBSUB_PROFILING == true ..
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      'Minimum latency ever detected.
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    + {field} minLatency : urt_delay_t
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      'Maximum latency ever detected.
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    + {field} maxLatency : urt_delay_t
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    __
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      'Initializes a urt_nrtsubscriber_t object.
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    + {method} urtNrtSubscriberInit (subscriber : urt_nrtsubscriber_t*) : void
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      'Tries to subscribe to a topic and optionally contributes a list of messages to the topic.
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    + {method} urtNrtSubscriberSubscribe (subscriber : urt_nrtsubscriber_t*, topic : urt_topic_t*, messages : urt_message_t*) : urt_status_t
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      'Fetches the next message in the buffer, optionally copies the payload and optionally returns the latency.
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    + {method} urtNrtSubscriberFetchNextMessage (subscriber : urt_nrtsubscriber_t*, payload : void*, bytes : size_t, latency : urt_delay_t*) : urt_status_t
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      'Fetches the latest message, optionally copies the payload and optionally returns the latency.
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    + {method} urtNrtSubscriberFetchLatestMessage (subscriber : urt_nrtsubscriber_t*, payload : void*, bytes : size_t, latency : urt_delay_t*) : urt_status_t
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      'Unsubscribes from a topic.
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    + {method} urtNrtSubscriberUnsubscribe (subscriber : urt_nrtsubscriber_t*) : urt_status_t
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  }
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  /' SRT subscriber type. '/
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  $structure("urt_srtsubscriber_t") {
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      'Callback to calculate usefulness of a message
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    + {field} usefulnesscb : urt_usefulness_f*
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      'Optional parameters for the usefulness callback function.
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    + {field} cbparams : void*
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    .. URT_CFG_PUBSUB_PROFILING == true ..
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      'Minimum latency ever detected.
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    + {field} minLatency : urt_delay_t
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      'Maximum latency ever detected.
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    + {field} maxLatency : urt_delay_t
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    __
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      'Initializes a urt_srtsubscriber_t object.
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    + {method} urtSrtSubscriberInit (subscriber : urt_srtsubscriber_t*) : void
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      'Tries to subscribe to a topic, sets all parameters and optionally contributes a list of messages to the topic.
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    + {method} urtSrtSubscriberSubscribe (subscriber : urt_srtsubscriber_t*, topic : urt_topic_t*, messages : urt_message_t*, usefulnesscb : urt_usefulness_f*, cbparams : void*) : urt_status_t
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      'Fetches the next message in the buffer, optionally copies the payload and optionally returns the latency.
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    + {method} urtSrtSubscriberFetchNextMessage (subscriber : urt_srtsubscriber_t*, payload : void*, bytes : size_t, latency : urt_delay_t*) : urt_status_t
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      'Fetches the latest message, optionally copies the payload and optionally returns the latency.
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    + {method} urtSrtSubscriberFetchLatestMessage (subscriber : urt_srtsubscriber_t*, payload : void*, bytes : size_t, latency : urt_delay_t*) : urt_status_t
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      'Calculates the usefulness of a message after the specified delay.
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    + {method} urtSrtSubscriberCalculateUsefulness (subscriber : urt_srtsubscriber_t*, latency : urt_delay_t) : float
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      'Unsubscribes from a topic.
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    + {method} urtSrtSubscriberUnsubscribe (subscriber : urt_srtsubscriber_t*) : urt_status_t
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  }
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  /' FRT subscriber type. '/
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  $structure("urt_frtsubscriber_t") {
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    .. URT_CFG_PUBSUB_QOS_DEADLINECHECKS == true ..
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      'Maximum temporal offset between creation and consumption of messages.
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    + {field} deadlineOffset : urt_delay_t
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    .. URT_CFG_PUBSUB_QOS_JITTERCHECKS == true ..
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      'Maximum expected jitter.
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    + {field} maxJitter : urt_delay_t
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    .. URT_CFG_PUBSUB_QOS_JITTERCHECKS == true ||  URT_CFG_PUBSUB_PROFILING == true ..
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      'Minimum latency ever detected (to calculate jitter).
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    + {field} minLatency : urt_delay_t
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      'Maximum latency ever detected (to calculate jitter).
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    + {field} maxLatency : urt_delay_t
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    __
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      'Initializes a urt_frtsubscriber_t object.
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    + {method} urtFrtSubscriberInit (subscriber : urt_frtsubscriber_t*) : void
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      'Tries to subscribe to a topic, sets all parameters and optionally contributes a list of messages to the topic.
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    + {method} urtFrtSubscriberSubscribe (subscriber : urt_frtsubscriber_t*, topic : urt_topic_t*, messages : urt_message_t*, deadline : urt_delay_t, jitter : urt_delay_t) : urt_status_t
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      'Fetches the next message in the buffer, optionally copies the payload and optionally returns the latency.
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    + {method} urtFrtSubscriberFetchNextMessage (subscriber : urt_frtsubscriber_t*, payload : void*, bytes : size_t, latency : urt_delay_t*) : urt_status_t
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      'Fetches the latest message, optionally copies the payload and optionally returns the latency.
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    + {method} urtFrtSubscriberFetchLatestMessage (subscriber : urt_frtsubscriber_t*, payload : void*, bytes : size_t, latency : urt_delay_t*) : urt_status_t
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      'Checks whether a message is valid after the specified delay.
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    + {method} urtFrtSubscriberCalculateValidity (subscriber : urt_frtsubscriber_t*, latency : urt_delay_t) : bool
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      'Unsubscribes from a topic.
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    + {method} urtFrtSubscriberUnsubscribe (subscriber : urt_frtsubscriber_t*) : urt_status_t
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  }
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  /' HRT subscriber type. '/
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  $structure("urt_hrtsubscriber_t") {
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      'Pointer to the next HRT subscriber in a list.
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    + {field} next : urt_hrtsubscriber_t*
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    .. URT_CFG_PUBSUB_QOS_DEADLINECHECKS == true ..
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      'Maximum temporal offset between creation and consumption of messages.
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    + {field} deadlineOffset : urt_delay_t
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      'QoS Timer to detect missed deadlines.
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    + {field} qosDeadlineTimer : urt_osTimer_t
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    .. URT_CFG_PUBSUB_QOS_JITTERCHECKS == true ..
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      'Maximum expected jitter.
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    + {field} maxJitter : urt_delay_t
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    .. URT_CFG_PUBSUB_QOS_JITTERCHECKS == true || URT_CFG_PUBSUB_PROFILING == true..
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      'Minimum latency ever detected (to calculate jitter).
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    + {field} minLatency : urt_delay_t
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      'Maximum latency ever detected (to calculate jitter).
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    + {field} maxLatency : urt_delay_t
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    .. URT_CFG_PUBSUB_QOS_RATECHECKS == true ..
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      'Expected rate at which data is published.
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    + {field} expectedRate : urt_delay_t
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    __
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      'Initializes a urt_hrtsubscriber_t object.
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    + {method} urtHrtSubscriberInit (subscriber : urt_hrtsubscriber_t*) : void
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      'Tries to subscribe to a topic, sets all parameters and optionally contributes a list of messages to the topic.
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    + {method} urtHrtSubscriberSubscribe (subscriber : urt_hrtsubscriber_t*, topic : urt_topic_t*, messages : urt_message_t*, deadline : urt_delay_t, rate : urt_delay_t, jitter : urt_delay_t) : urt_status_t
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      'Fetches the next message in the buffer, optionally copies the payload and optionally returns the latency.
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    + {method} urtHrtSubscriberFetchNextMessage (subscriber : urt_hrtsubscriber_t*, payload : void*, bytes : size_t, latency : urt_delay_t*) : urt_status_t
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      'Fetches the latest message, optionally copies the payload and optionally returns the latency.
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    + {method} urtHrtSubscriberFetchLatestMessage (subscriber : urt_hrtsubscriber_t*, payload : void*, bytes : size_t, latency : urt_delay_t*) : urt_status_t
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      'Unsubscribes from a topic.
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    + {method} urtHrtSubscriberUnsubscribe (subscriber : urt_hrtsubscriber_t*) : urt_status_t
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  }
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} /'subscriber'/
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/' Publisher type. '/
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$structure("urt_publisher_t") {
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  'Flag, whether the publish() method supports timeout.
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  URT_PUBSUB_PUBLISHER_PUBLISH_TIMEOUT : bool
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  __
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    'Pointer to the topic for publishing.
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  + {field} topic : urt_topic_t*
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  .. URT_CFG_PUBSUB_PROFILING == true ..
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    'Counter of attempts to publish a message.
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  + {field} publishAttempts : uint64_t
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    'Counter of failed attempts to publish a message.
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  + {field} publishFails : uint64_t
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  __
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    'Initializes a urt_publisher_t object and contributes an optional list of messages.
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  + {method} urtPublisherInit (publisher : urt_publisher_t*, topic : urt_topic_t*, messages : urt_message_t*) : void
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  .. URT_PUBSUB_PUBLISHER_PUBLISH_TIMEOUT == false ..
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    'Publishes a message via the associated topic.
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  + {method} urtPublisherPublish (publisher : urt_publisher_t*, payload : void*, bytes : size_t, t : urt_osTime_t) : urt_status_t
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  .. URT_PUBSUB_PUBLISHER_PUBLISH_TIMEOUT == true ..
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    'Publishes a message via the associated topic with timeout.
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  + {method} urtPublisherPublish (publisher : urt_publisher_t*, payload : void*, bytes : size_t, t : urt_osTime_t, timeout : urt_delay_t) : urt_status_t
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}
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/' Topic type. '/
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$structure("urt_topic_t") {
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    'Pointer to the next topic in a list.
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  + {field} next : urt_topic_t*
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    'Identifier of the topic.
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  + {field} id : urt_topicid_t
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    'Mutex lock for exclusive access.
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  + {field} lock : urt_osMutex_t
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    'Event source to inform all subscribers when a new message is published.
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  + {field} evtSource : urt_osEventSource_t
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    'Number of HRT subscribers.
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  + {field} numHrtSubscribers : unsigned int
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    'Condition variable to inform waiting publishers when a blocked message becomes available.
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  + {field} hrtReleased : urt_osCondvar_t
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    'Mandatory message, each Topic holds.
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  + {field} mandatoryMessage : urt_message_t
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    'Pointer to the latest message.
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  + {field} latestMessage : urt_message_t*
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  .. URT_CFG_PUBSUB_QOS_RATECHECKS == true ..
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    'List of HRT subscribers, orderd by their expected rate (most critical first).
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  + {field} hrtSubscribers : urt_hrtsubscriber_t*
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    'Timer to check for missed rates.
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  + {field} qosRateTimer : urt_osTimer_t
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  .. URT_CFG_PUBSUB_PROFILING == true ..
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    'Number of overall published messages on this topic.
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  + {field} numMessagesPublished : uint64_t
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    'Variable to count how often (non-hrt) subscribers did not fetch a message before it was reused.
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  + {field} numMessagesDiscarded : uint64_t
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    'Number of overall subscribers.
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  + {field} numSubscribers : unsigned int
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  __
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    'Initializes an urt_topic_t object.
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  + {method} urtTopicInit (topic : urt_topic_t*, id : urt_topicid_t) : urt_status_t
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}
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!endsub
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/'### DEPENDENCIES & LAYOUT ##################################################'/
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!startsub DEPENDENCIES
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urt_message_t "1" o- "0,1" urt_message_t
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urt_basesubscriber_t "1" o-- "0,1" urt_message_t
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urt_nrtsubscriber_t --|> urt_basesubscriber_t
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urt_srtsubscriber_t --|> urt_basesubscriber_t
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urt_frtsubscriber_t --|> urt_basesubscriber_t
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urt_hrtsubscriber_t --|> urt_basesubscriber_t
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urt_hrtsubscriber_t "1" o- "0,1" urt_hrtsubscriber_t
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urt_publisher_t "1" o- "1" urt_topic_t
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urt_publisher_t ..> urt_message_t
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urt_topic_t "1" o- "0,1" urt_topic_t
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urt_topic_t "1" o- "0,1" urt_hrtsubscriber_t
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urt_topic_t "1" *-- "1" urt_message_t
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!endsub
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/'### OUTRO ##################################################################'/
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@enduml
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