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simgear/simgear/io/SGDataDistributionService.hxx
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/**
* \file SGDataDistributionService.hxx
* Data Distribution Service (DDS) I/O routines
*/
// Written by Erik Hofman, started March 2021.
//
// Copyright (C) 2021 by Erik Hofman <erik@ehofman.com>
//
// 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 2 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, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
//
// $Id$
#ifndef _SG_DDS_Topic_HXX
#define _SG_DDS_Topic_HXX
#include <string>
#include <vector>
#include <dds/dds.h>
#include <simgear/compiler.h>
#include <simgear/math/sg_types.hxx>
#include <simgear/io/iochannel.hxx>
#include <simgear/structure/intern.hxx>
#define FG_DDS_DOMAIN DDS_DOMAIN_DEFAULT
// Data Distribution Service (DDS) class based on SGIOChannel.
class SG_DDS_Topic : public SGIOChannel {
private:
std::string topic_name;
const dds_topic_descriptor_t *descriptor = nullptr;
size_t packet_size = 0;
uint32_t status = 0;
bool shared_participant = true;
dds_entity_t participant = -1;
dds_entity_t topic = -1;
dds_entity_t entry = -1;
public:
/** Create an instance of SG_DDS_Topic. */
SG_DDS_Topic();
SG_DDS_Topic(const char* topic, const dds_topic_descriptor_t *desc, size_t size);
template<typename T>
SG_DDS_Topic(T& type, const dds_topic_descriptor_t *desc) : SG_DDS_Topic() {
setup<T>(desc);
}
/** Destructor */
virtual ~SG_DDS_Topic();
// Set the paramaters which weren't available at creation time and use
// a custom topic name.
void setup(const char* topic, const dds_topic_descriptor_t *desc, size_t size);
template<typename T>
void setup(const dds_topic_descriptor_t *desc) {
std::string type = simgear::getTypeName<T>();
setup(type.c_str(), desc, sizeof(T));
}
// If specified as a server start a publishing participant.
// If specified as a client start a subscribing participant.
bool open(const SGProtocolDir d);
// If specified as a server start publishing to a participant.
// If specified as a client start subscribing to a participant.
bool open(dds_entity_t p, const SGProtocolDir d);
// read data from the topic.
int read(char *buf, int length);
template<typename T>
bool read(T& sample) {
return (read((char*)&sample, sizeof(T)) == sizeof(T)) ? true : false;
}
// write data to the topic.
int write(const char *buf, const int length);
template<typename T>
bool write(const T& sample) {
return (write((char*)&sample, sizeof(T)) == sizeof(T)) ? true : false;
}
// close the participant.
bool close();
dds_entity_t get() { return entry; }
};
// a class to manage multiple DDS topics
class SG_DDS {
private:
dds_entity_t participant = -1;
dds_domainid_t domain = FG_DDS_DOMAIN;
dds_entity_t waitset = -1;
std::vector<SG_DDS_Topic*> readers;
std::vector<SG_DDS_Topic*> writers;
public:
SG_DDS(dds_domainid_t d = FG_DDS_DOMAIN);
~SG_DDS();
bool add(SG_DDS_Topic *topic, const SGProtocolDir d);
bool close();
const std::vector<SG_DDS_Topic*>& get_readers() { return readers; }
const std::vector<SG_DDS_Topic*>& get_writers() { return writers; }
bool wait(float dt = 0.0f);
};
#endif // _SG_DDS_Topic_HXX