memory_info.h

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/****************************************************************************
* VCGLib                                                            o o     *
* Visual and Computer Graphics Library                            o     o   *
*                                                                _   O  _   *
* Copyright(C) 2004                                                \/)\/    *
* Visual Computing Lab                                            /\/|      *
* ISTI - Italian National Research Council                           |      *
*                                                                    \      *
* All rights reserved.                                                      *
*                                                                           *
* 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 (http://www.gnu.org/licenses/gpl.txt)          *
* for more details.                                                         *
*                                                                           *
****************************************************************************/

#ifndef __MEMORY_INFO_H
#define __MEMORY_INFO_H

#include <stdexcept>

namespace vcg 
{
        //WARNING: All the classes derived from MemoryInfo has been intended to be instantiated as a singleton in the host application 
        //(i.e. in every application using it just an instance of a class derived from MemoryInfo should be declared).

        class MemoryInfo
        {
        public:
                class MemoryInfoException : public std::exception
                {
                public:
                        MemoryInfoException(const char* text)
                                :std::exception(),_exctext(text){}

                        ~MemoryInfoException() throw() {}
                        inline const char* what() const throw() {return _exctext;}
                private:
                        const char* _exctext;
                };

                MemoryInfo(std::ptrdiff_t originalmem)
                        :_originaltotalmemory(originalmem),_currentfreememory(_originaltotalmemory)
                {       
                }

                virtual ~MemoryInfo() {}
                virtual void acquiredMemory(std::ptrdiff_t mem) = 0;
                virtual std::ptrdiff_t usedMemory() const = 0;
                virtual std::ptrdiff_t currentFreeMemory() const = 0;
                virtual void releasedMemory(std::ptrdiff_t mem = 0) = 0;
                virtual bool isAdditionalMemoryAvailable(std::ptrdiff_t mem) = 0;

        protected:
                const std::ptrdiff_t _originaltotalmemory;
                std::ptrdiff_t _currentfreememory;
        };

        //WARNING: this is not a thread safe class. The object derived from MemoryInfo are intended to be used inside GLMeshAttributeFeeder as static variable in order to manage the available GPUMemory.
        //We strongly recommend you to define in your code a thread safe version of the class, defining mutexed access member functions. 
        //This class should be consider just as a basic example for the implementations of the required functionalities. 
        //It is safe to use it just when the user has only one mesh to pass to the GPU.

        class NotThreadSafeMemoryInfo : public MemoryInfo
        {
        public:
                NotThreadSafeMemoryInfo(std::ptrdiff_t originalmem)
                        :MemoryInfo(originalmem)
                {
                }

                ~NotThreadSafeMemoryInfo() {}

                void acquiredMemory(std::ptrdiff_t mem)
                {
                        if (mem > _originaltotalmemory)
                                throw MemoryInfo::MemoryInfoException("It has been requested more memory than the total one.\\n");
                        else 
                                if (mem > _currentfreememory)
                                        throw MemoryInfo::MemoryInfoException("It has been requested more memory than the free available one.\\n");
                                else
                                        _currentfreememory -= mem;
                }

                std::ptrdiff_t usedMemory() const
                {
                        return _originaltotalmemory - _currentfreememory;
                }

                std::ptrdiff_t currentFreeMemory() const
                {
                        return _currentfreememory;
                }

                void releasedMemory(std::ptrdiff_t mem = 0)
                {
                        if (mem > _originaltotalmemory)
                                throw MemoryInfo::MemoryInfoException("It has been released more memory than the total one. Something strange happened!\\n");
                        else
                                _currentfreememory += mem;
                }

                bool isAdditionalMemoryAvailable(std::ptrdiff_t mem)
                {
                        return (_currentfreememory >= mem);
                }
        };
};

#endif