source: flair-src/tags/latest/lib/FlairIpc/src/unexported/shm_receive.h@ 456

/**
 * \file ipc_receive.h
 * \brief definition de classe
 * \author {
 *                      Sébastien Ambroziak
 *                      Paul Sauvage
 *                      }
 * \version 0.1
 * \date 5 novembre 2020
 *
 * Definitions de la classe IpcReceiver ainsi que ses méthodes.
 * Cette classe permet de recevoir des structures ou des liste de structure par ipc
 * 
 * La classe IpcReceiver utilise une template à 2 paramètres, T et N
 *      le paramètre T correspond au type de donnée que le receiver doit recevoir
 *      le paramètre N correspond au nombre d'élément du tableau d'élément de type T à recevoir
 *              si N = 0 la fonction receive() retourne directement un objet de type T
 *              si N > 0 la fonction receive() retourne un pointeur de type T et donc un tableau d'élément T de N éléments
 * 
 * Le constructeur utilise 2 paramètres:
 *  Une chaîne de caractère contenant le nom du fichier ipc vers lequel lire les données
 *  Un entier correspond au numéro de canal Ipc
 * 
 */



#ifndef SHM_RECEIVE
#define SHM_RECEIVE

#include "ipc_base.h"

#include <functional>
#include <memory>
#include <iostream>
#include <stdio.h>
#include <type_traits>
#include <cstring>

#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/sem.h>
#include <sys/time.h>
#include <string>
#include <errno.h>

using namespace std;
using namespace ipc::type;

class ShmReceiverBase {
        public:
                ShmReceiverBase(size_t msg_size, const char* ipc_name, int proj_id=65){
                        cout << "Creating ShmReceiver" << endl;
                        system("mkdir -p /tmp/shmem");
                        system("chmod 777 /tmp/shmem");
                        string pathname = string("/tmp/shmem/") + string(ipc_name);
                        string command = string("> ") + pathname;
                        system(command.c_str());
                        command = string("chmod 666 ") + pathname;
                        system(command.c_str());

                        key_t ipc_key = ftok(pathname.c_str(), proj_id); //crete unique key
                        cout << "clé ipc" << ipc_key << endl;

                        _shmid = shmget(ipc_key, msg_size, 0666|IPC_CREAT); // shmget returns an identifier in shmid 
                        cout << "Shm Id : " << _shmid << endl;

                        _semid=semget(ipc_key,1,IPC_CREAT|0666);
                        cout << "Sem Id : " << _semid << endl;

                        /*struct shmid_ds buf;
                        shmctl(_shmid, IPC_STAT,&buf);
                        buf.shm_perm.mode = (S_IRWXU|S_IRWXG|S_IRWXO);
                        shmctl(_shmid, IPC_SET,&buf);*/
                }

                ~ShmReceiverBase(){
                        shmctl(_shmid, IPC_RMID, NULL); // destroy the shared memory 
                        semctl(_semid, 0, IPC_RMID); // destroy semaphore
                } 

        protected:
                int _shmid;
                int _semid;
                struct sembuf _semaphore; 
};

template <typename T>
class ShmReceiver : ShmReceiverBase {
        public:
                ShmReceiver(const char* ipc_name, int proj_id=65, bool auto_refresh = false): ShmReceiverBase(sizeof(ipc_message<T>), ipc_name, proj_id), _auto_refresh(auto_refresh) {}
                ~ShmReceiver() = default;

                int receive(){
                        int return_value = 0;
                        _semaphore.sem_num=0;
                        _semaphore.sem_op=-1; //getMutex
                        semop(_semid,&_semaphore,1);

                        if ((tmp.sec == _shm_ptr->data.stamp.sec) && (tmp.nanosec == _shm_ptr->data.stamp.nanosec)){
                                return_value = -1; //Donnée obsolète
                                
                                if(_auto_refresh == true){
                                        refreshTime();
                                }
                        }
                        else{
                                tmp.sec = _shm_ptr->data.stamp.sec;
                                tmp.nanosec = _shm_ptr->data.stamp.nanosec;
                                memcpy(&_message, _shm_ptr, sizeof(ipc_message<T>)); //write message
                        }
                        
                        _semaphore.sem_num=0;
                        _semaphore.sem_op=1; //release mutex
                        semop(_semid,&_semaphore,1);

                        return return_value;
                }

                timestamp getTimestamp() const {
                        return _message.data.stamp;
                }

                T getValue() const {return _message.data.value;}

                timestamp refreshTime(){
                        _message.time_now();
                        return _message.data.stamp;
                }


        protected:
                timestamp tmp;
                bool _auto_refresh;
                ipc_message<T> *_shm_ptr = (ipc_message<T>*) shmat(_shmid,(void*)0, SHM_RDONLY); // shmat to attach to shared memory 
                ipc_message<T> _message;
                bool _blocking;
};

template <typename T>
class ShmReceiverTab : ShmReceiverBase {
        public:
                ShmReceiverTab(size_t N, const char* ipc_name, int proj_id=65, bool auto_refresh = false): ShmReceiverBase(sizeof(ipc_tab<T>) + sizeof(T)*(N-1), ipc_name, proj_id), _N(N), _auto_refresh(auto_refresh) {
                        _message = (ipc_tab<T>*) malloc(sizeof(ipc_tab<T>) + sizeof(T)*N);
                }

                ~ShmReceiverTab() = default;

                int receive(){
                        
                        int return_value = 0;
                        _semaphore.sem_num=0;
                        _semaphore.sem_op=-1; //getMutex
                        semop(_semid,&_semaphore,1);

                        if ((tmp.sec == _shm_ptr->data.stamp.sec) && (tmp.nanosec == _shm_ptr->data.stamp.nanosec)){
                                return_value = -1; //Donnée obsolète
                                if(_auto_refresh == true)
                                        refreshTime();
                        }
                        else{
                                tmp.sec = _shm_ptr->data.stamp.sec;
                                tmp.nanosec = _shm_ptr->data.stamp.nanosec;
                                memcpy(_message, _shm_ptr, sizeof(ipc_tab<T>) + sizeof(T)*_N); //write message
                        }
                        
                        _semaphore.sem_num=0;
                        _semaphore.sem_op=1; //release mutex
                        semop(_semid,&_semaphore,1);

                        return return_value;
                }
                
                T getValue(size_t index) const {
                        return _message->data.values[index];
                }

                const T* getValues() const {
                        return _message->data.values;
                }

                timestamp getTimestamp() const {
                        return _message->data.stamp;
                }

                size_t getN() const {return _N;}

                timestamp refreshTime(){
                        _message->time_now();
                        return _message->data.stamp;
                }

                void setAll(T value) {
                        for (size_t i = 0; i < _N; i++)
                        {
                                _message->data.values[i] = value;
                        }
                }

        protected:
                timestamp tmp;
                size_t _N;
                bool _auto_refresh;
                ipc_tab<T> *_message;
                ipc_tab<T> *_shm_ptr = (ipc_tab<T>*) shmat(_shmid,(void*)0,SHM_RDONLY); // shmat to attach to shared memory 
                
};

#endif