Buffer.hpp

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/*******************************************************************************
 *
 * Copyright (c) 2010-2015   Edans Sandes
 *
 * This file is part of MASA-Core.
 * 
 * MASA-Core 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 3 of the License, or
 * (at your option) any later version.
 * 
 * MASA-Core 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 MASA-Core.  If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/

#ifndef BUFFER_H
#define BUFFER_H

#include <pthread.h>
#include <string>
using namespace std;

#include "../io/CellsReader.hpp"
#include "../io/CellsWriter.hpp"

struct buffer_statistics_t {
        float time;
        int bufferUsage;
        int totalBytes;
        float blockingTime;

        const buffer_statistics_t operator-(const buffer_statistics_t &other) const {
                buffer_statistics_t ret;
                ret.time = this->time - other.time;
                ret.bufferUsage = this->bufferUsage - other.bufferUsage;
                ret.totalBytes = this->totalBytes - other.totalBytes;
                ret.blockingTime = this->blockingTime - other.blockingTime;
                return ret;
        }
};



class Buffer : public CellsReader, public CellsWriter
{
public:
        Buffer();
        virtual ~Buffer();
        
        virtual int read(cell_t* data, int nmemb);
        virtual int write(const cell_t* data, int nmemb);
        virtual int getType();

        int readBuffer(char* data, int size, int nmemb);
        int writeBuffer(const char* data, int size, int nmemb);
        void waitEmptyBuffer();
        
        void destroy();
        bool isDestroyed();

    virtual void autoFlushThread() = 0;
    virtual void autoLoadThread() = 0;
    
    virtual void initAutoFlush() = 0;
    virtual void initAutoLoad() = 0;

    /**
     * This method is called prior to the auto-load thread destruction.
     * See the Buffer::destroyAutoLoad() method description.
     */
    virtual void destroyAutoFlush() = 0;

    /**
     * This method is called prior to the auto-load thread destruction.
     * For example, if the auto-load thread is waiting for a socket input,
     * then the destroyAutoLoad must destroy the socket in order to wake
     * the thread execution. Note that during and after this method is called,
     * the Buffer::isDestroyed() method will always return true.
     */
    virtual void destroyAutoLoad() = 0;
    
        void autoFlush();
        void autoLoad();
        
        /**
         * Use this method only for statistics purpose, since the returned value
         * is volatile and not synchronized (without mutex).
         * @return the number of bytes in the buffer.
         */
        int getUsage();

        /**
         * Returns the maximum capacity in bytes of the buffer.
         * @return The size of the buffer in bytes.
         */
        int getCapacity();

        /**
         * Returns the number of milliseconds that was blocked waiting for data.
         * @return blocking time in readBuffer method.
         */
        float getBlockingReadTime();

        /**
         * Returns the number of milliseconds that was blocked waiting for space.
         * @return blocking time in writeBuffer method.
         */
        float getBlockingWriteTime();

        /**
         * Returns the amount of bytes written in the buffer since its creation.
         * @return the number of bytes written.
         */
        int getBytesWritten();

        /**
         * Returns the amount of bytes read from the buffer since its creation.
         * @return the number of bytes read.
         */
        int getBytesRead();

        /**
         * Returns a struct containing statistics of the buffer.
         * @return statistics of the buffer.
         */
        buffer_statistics_t getStatistics();

        /**
         * Defines a logfile to receive the buffer statistics in each
         * interval period.
         *
         * @param logFile the filename of the log file.
         * @param interval The period in seconds to log the statistics.
         */
    void setLogFile(string logFile, int interval);

        private:
                float blockingReadTime;
                float blockingWriteTime;
                int volatileUsage;
                int bytesRead;
                int bytesWritten;

        float tempBlockingWriteTime;
        float tempBlockingReadTime;


                pthread_mutex_t mutex;
                pthread_cond_t notFullCond;
                pthread_cond_t notEmptyCond;
                pthread_cond_t emptyCond;
                pthread_cond_t loggerCond;
                
                bool destroyed;
                
                char* buffer;
                int buffer_size;
                int buffer_start;
                int buffer_end;
                int buffer_max;

        pthread_t threadId;
        bool inputBuffer;
        
        pthread_t loggerThread;
        string logFile;
        bool isLogging;
        int logInterval; // in seconds

                int circularLoad(char *dst, int len);
                int circularStore(const char *src, int len);
                int sizeUsed();
                int sizeAvailable();

        static void* staticFlushThread(void *arg);
        static void* staticLoadThread(void *arg);
        static void* staticLogThread(void *arg);

        void createAutoLoadThread();
        void createAutoFlushThread();
            void logThread();

                void joinThreads();
};

#endif // BUFFER_H