Memoire partagee interapplication

include/Utils/shared_mem.h

+/*******************************************************************************
+* CGoGN: Combinatorial and Geometric modeling with Generic N-dimensional Maps  *
+* version 0.1                                                                  *
+* Copyright (C) 2009, IGG Team, LSIIT, University of Strasbourg                *
+*                                                                              *
+* This library is free software; you can redistribute it and/or modify it      *
+* under the terms of the GNU Lesser General Public License as published by the *
+* Free Software Foundation; either version 2.1 of the License, or (at your     *
+* option) any later version.                                                   *
+*                                                                              *
+* This library 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 Lesser General Public License  *
+* for more details.                                                            *
+*                                                                              *
+* You should have received a copy of the GNU Lesser General Public License     *
+* along with this library; if not, write to the Free Software Foundation,      *
+* Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.           *
+*                                                                              *
+* Web site: https://iggservis.u-strasbg.fr/CGoGN/                              *
+* Contact information: cgogn@unistra.fr                                        *
+*                                                                              *
+*******************************************************************************/
+
+#ifndef __CGoGN_MEM_SHARED_
+#define __CGoGN_MEM_SHARED_
+
+
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/shm.h>
+#include <stdlib.h>
+#include <iostream>
+
+
+namespace CGoGN
+{
+
+namespace Utils
+{
+/**
+* Shared Memory Segment management
+* Example:
+*  in master:
+*    SharedMem<MY_DATA> shm;
+*    shm.initMaster(4321);
+*    ...
+*     *(shm.lockForWrite()) = localData;
+*     shm.release();
+*    ...
+*  in slave
+*    SharedMem<MY_DATA> shm;
+*    shm.initSlace(4321);
+*    ...
+*	 MY_DATA localData = *(shm.dataRead());
+*    ...
+*/
+template<typename DATA>
+class SharedMemSeg
+{
+protected:
+	int m_mem_id;
+	int* m_ptr;
+	DATA* m_ptr1;
+	DATA* m_ptr2;
+public:
+	
+	/**
+	* Constructor
+	*/
+	SharedMemSeg();
+
+	/**
+	* Destructor
+	*/
+	~SharedMemSeg();
+	
+	/**
+	* Initialization for master
+	* @param key key of shared mem zone
+	*/
+	bool initMaster(int key);
+
+	/**
+	* Initialization for master
+	* @param key key of shared mem zone
+	*/
+	bool initSlave(int key);
+
+	/**
+	* read data 
+	* @return a pointer on data (for copy or read)
+	*/
+	DATA* dataRead();
+	
+	/**
+	* lock data for writing. 
+	* @return a pointer on data (back buffer) to copy data in
+	*/	
+	DATA* lockForWrite();
+
+	/**
+	* release the data ( switch ptr from back to front)
+	*/
+	void release();
+
+};
+
+}
+}
+
+#include "Utils/shared_mem.hpp"
+
+#endif
+
+
+

include/Utils/shared_mem.hpp

+/*******************************************************************************
+* CGoGN: Combinatorial and Geometric modeling with Generic N-dimensional Maps  *
+* version 0.1                                                                  *
+* Copyright (C) 2009, IGG Team, LSIIT, University of Strasbourg                *
+*                                                                              *
+* This library is free software; you can redistribute it and/or modify it      *
+* under the terms of the GNU Lesser General Public License as published by the *
+* Free Software Foundation; either version 2.1 of the License, or (at your     *
+* option) any later version.                                                   *
+*                                                                              *
+* This library 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 Lesser General Public License  *
+* for more details.                                                            *
+*                                                                              *
+* You should have received a copy of the GNU Lesser General Public License     *
+* along with this library; if not, write to the Free Software Foundation,      *
+* Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.           *
+*                                                                              *
+* Web site: https://iggservis.u-strasbg.fr/CGoGN/                              *
+* Contact information: cgogn@unistra.fr                                        *
+*                                                                              *
+*******************************************************************************/
+
+
+namespace CGoGN
+{
+
+namespace Utils
+{
+
+
+template<typename DATA>
+SharedMemSeg<DATA>::SharedMemSeg():
+m_ptr(NULL) 
+{ }
+
+template<typename DATA>
+SharedMemSeg<DATA>::~SharedMemSeg()
+{ 
+	if (m_ptr !=NULL)
+	{
+		struct shmid_ds buf;
+		shmctl(m_mem_id,IPC_RMID, &buf);
+		shmdt(m_ptr);
+	}
+}
+
+template<typename DATA>
+bool SharedMemSeg<DATA>::initMaster(int key)
+{
+	m_mem_id = shmget(key, 2*sizeof(DATA)+2*sizeof(int), IPC_CREAT|0666);
+	if (m_mem_id < 0)
+	{
+		std::cerr << "Error shmget"<<std::endl;
+		return false;
+	}
+
+	m_ptr = reinterpret_cast<int*>(shmat(m_mem_id, NULL, 0));
+	if (m_ptr ==  (int*)-1)
+	{
+		std::cerr << "Error shmat"<<std::endl;
+		return false;
+	}
+
+	m_ptr1 = reinterpret_cast<DATA*>(m_ptr + 2);
+	m_ptr2 = m_ptr1+1;
+	*m_ptr = 0;
+}
+
+template<typename DATA>
+bool SharedMemSeg<DATA>::initSlave(int key)
+{
+	m_mem_id = shmget(key, 2*sizeof(DATA)+2*sizeof(int), 0444);
+	if (m_mem_id < 0)
+	{
+		std::cerr <<"Shared Memory "<< key << " does not exist can not read"<< std::endl;
+		return false;
+	}
+
+	m_ptr = reinterpret_cast<int*>(shmat(m_mem_id, NULL, 0));
+	if (m_ptr ==  (int*)-1)
+	{
+		std::cerr <<"Problem getting shared memory ptr for "<< key << std::endl;
+		return false;
+	}
+		
+	m_ptr1 = reinterpret_cast<DATA*>(m_ptr + 2);
+	m_ptr2 = m_ptr1+1;
+	*(int*)m_ptr = 0;
+}
+
+	
+template<typename DATA>
+DATA*  SharedMemSeg<DATA>::dataRead()
+{
+	if (*m_ptr == 0)
+		return m_ptr1;
+	return  m_ptr2;
+}
+
+
+template<typename DATA>
+DATA*  SharedMemSeg<DATA>::lockForWrite()
+{
+	if (*m_ptr == 0)
+		return m_ptr2;
+	return m_ptr1;
+}
+
+template<typename DATA>
+void  SharedMemSeg<DATA>::release()
+{
+	*m_ptr = 1 - *m_ptr;	//invert id		
+}
+
+
+}
+}
+
+