/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *                                                                         *
 *   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 for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the Free Software           *
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston,                 *
 *   MA  02111-1307  USA                                                   *
 ***************************************************************************/

#ifndef __CONDITION_H__
#define __CONDITION_H__

#include "Mutex.h"

/**
 * Thread safe boolean condition.
 *
 * This is not meant to be used for real time operation!
 */
class Condition : public Mutex {
    public:
        /**
         * Constructor
         *
         * @param bInitialCondition - optional: starting condition
         *                            (default = false)
         */
        Condition(bool bInitialCondition = false);

        /**
         * Destructor
         */
        ~Condition();

        /**
         * Blocks the calling thread if current condition equals
         * \a bCondition, in this case the calling thread will be blocked
         * until condition turns. Upon successful return the Condition
         * object is locked, so the calling thread can safely run it's
         * critical section and has to explicitly call Unlock() right after
         * it left it's critcal section.
         *
         * @param bCondition         - block in case of this condition
         * @param TimeoutSeconds     - optional: max. wait time in seconds
         *                             (default: 0s)
         * @param TimeoutNanoSeconds - optional: max wait time in nano
         *                             seconds (default: 0ns)
         * @returns  0 on success, a value less than 0 if timeout exceeded
         */
        int WaitIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);

        /**
         * Same as WaitIf(), except that WaitAndUnlockIf() will unlock the
         * Condition object, so only use this call if you don't need to
         * enter a thread critical section, otherwise use WaitIf() instead!
         *
         * @param bCondition         - block in case of this condition
         * @param TimeoutSeconds     - optional: max. wait time in seconds
         *                             (default: 0s)
         * @param TimeoutNanoSeconds - optional: max wait time in nano
         *                             seconds (default: 0ns)
         * @returns  0 on success, a value less than 0 if timeout exceeded
         * @see WaitIf()
         */
        int WaitAndUnlockIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);

        /**
         * Set Condition object to \a bCondition. Upon change of the
         * condition, other threads waiting for \a bCondition will be
         * awakened.
         *
         * @param bCondition - new condition
         */
        void Set(bool bCondition);

    protected:
        pthread_cond_t __posix_true_condition;
        pthread_cond_t __posix_false_condition;
        bool bCondition;
};

#endif // __CONDITION_H__