x3c/include/X3cFileBuf.h

/*
 * X3cFileBuf.h
 *
 *  Created on: Jan 23, 2011
 *      Author: nilham
 */

#ifndef X3CFILEBUF_H_
#define X3CFILEBUF_H_

#include <pthread.h>

/*
 * Forward declaration to avoid circular inclusions.
 */
class X3cFileThreadReader;

/*
 * Class for controlling access to buffer area.
 *
 * Notice that the methods all shall be synchronized
 * through mutex access. It may not be necessary
 * for some methods, but is there for consistency.
 */
class X3cFileBuf
{
public:
        /*
         * Construct and set buffer start and end pointers.
         */
        X3cFileBuf(X3cFileThreadReader *parent, unsigned int bufNum, char *start, size_t len);
        /*
         * Destroy, destroy, destroy...
         */
        virtual ~X3cFileBuf();
        /*
         * Close the buffer.
         * Assumption is that close is ONLY called from reader thread,
         * in which case we know that it's only the writer thread that
         * has to be released.
         */
        void close();
        /*
         * Wait until buffer is empty.
         * Returns true if wait was OK and false if buffer was closed.
         */
        bool waitForWrite();
        /*
         * Wait until buffer isn't empty.
         * Returns true if wait was OK and false if buffer was closed.
         */
        bool waitForRead();
        /*
         * Get length of real data in the buffer.
         * Notice: May be zero, which indicates either unloaded buffer or EOF.
         */
        size_t getDataLen();
        /*
         * Mark buffer as filled and release buffer for read.
         *
         * @realLen - Actual amount written into buffer,
         *            which may be less than the buffer size
         *            when EOF is encountered.
         */
        void setFilled(size_t realLen);
        /*
         * Mark buffer as empty and release buffer for write.
         */
        void setEmpty();
        /*
         * Get the pointer to the buffer.
         */
        char *getBufPtr();
        /*
         * Get the size of the buffer.
         */
        size_t getBufSize();
        /*
         * Set EOF flag.
         */
        void setEof(bool eof);
        /*
         * Check EOF flag.
         */
        bool isEof();
        /*
         * See if buf is flagged empty.
         */
        bool isEmpty();

private:
        X3cFileThreadReader *parent;
        bool valid;
        bool empty;
        bool busy;
        bool eof;
        char *start;
        size_t dataLen;
        size_t bufLen;
        pthread_mutex_t mRWMutex;
        pthread_cond_t writeWaiter;
        pthread_cond_t readWaiter;
        unsigned int bufNum;
};

#endif /* X3CFILEBUF_H_ */