SharedMemory.h

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/*
 * This file is part of ArmarX.
 *
 * ArmarX is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * ArmarX 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/>.
 *
 * @package    ...
 * @author     Andre Meixner ( andre dot meixner at kit dot edu )
 * @date       2024
 * @copyright  http://www.gnu.org/licenses/gpl-2.0.txt
 *             GNU General Public License
 */
 
#pragma once
 
#include <boost/interprocess/creation_tags.hpp>
#include <boost/interprocess/detail/os_file_functions.hpp>
#include <boost/interprocess/interprocess_fwd.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <boost/interprocess/shared_memory_object.hpp>
#include <boost/interprocess/sync/named_semaphore.hpp>
 
#include <ArmarXCore/core/logging/Logging.h>
 
namespace armarx::control::njoint_controller::task_space
{
    inline boost::interprocess::shared_memory_object
    InitSHM(const std::string& sharedMemoryName)
    {
        boost::interprocess::shared_memory_object::remove(sharedMemoryName.c_str());
        boost::interprocess::permissions permissions;
        //permissions.set_unrestricted(); // potential way to activate permissions for other users
        return boost::interprocess::shared_memory_object(boost::interprocess::create_only,
                                                         sharedMemoryName.c_str(),
                                                         boost::interprocess::read_write,
                                                         permissions);
    }
 
    inline boost::interprocess::named_semaphore
    InitSem(const std::string& semName)
    {
        boost::interprocess::named_semaphore::remove(semName.c_str());
        return boost::interprocess::named_semaphore(
            boost::interprocess::create_only, semName.c_str(), 0);
    }
 
    template <typename T>
    class SharedMemoryWriter
    {
    public:
        SharedMemoryWriter(const std::string& sharedMemoryName, const std::string& semName) :
            sem(InitSem(semName)), shm(InitSHM(sharedMemoryName))
        {
            ARMARX_INFO << "Initializing SharedMemoryWriter";
 
            shm.truncate(T::size());
            region = boost::interprocess::mapped_region(shm, boost::interprocess::read_write);
 
            ARMARX_INFO << "Finished creation of SharedMemoryWriter of size " << T::size();
        }
 
        inline void
        updateNonLocking(const T& data) const
        {
            std::memcpy(region.get_address(), &data, sizeof(T));
        }
 
        boost::interprocess::named_semaphore sem;
 
    private:
        boost::interprocess::shared_memory_object shm;
        boost::interprocess::mapped_region region;
    };
 
    template <typename T>
    class SharedMemoryReader
    {
    public:
        SharedMemoryReader(const std::string& sharedMemoryName, const std::string& semName) :
            sem(InitSem(semName)), shm(InitSHM(sharedMemoryName))
        {
            ARMARX_INFO << "Initializing SharedMemoryReader";
 
            shm.truncate(T::size());
            region = boost::interprocess::mapped_region(shm, boost::interprocess::read_write);
 
            ARMARX_INFO << "Finished creation of SharedMemoryReader of size" << T::size();
        }
 
        inline void
        updateNonLocking(T& data) const
        {
            std::memcpy(&data, region.get_address(), T::size());
        }
 
        boost::interprocess::named_semaphore sem;
 
    private:
        boost::interprocess::shared_memory_object shm;
        boost::interprocess::mapped_region region;
    };
 
} // namespace armarx::control::njoint_controller::task_space