src/common/Condition.h

/***************************************************************************
 *                                                                         *
 *   LinuxSampler - modular, streaming capable sampler                     *
 *                                                                         *
 *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
 *   Copyright (C) 2005 - 2007 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"

namespace LinuxSampler {

/**
 * 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
         */
        virtual ~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.
         *
         * @e Note: If you don't provide a timeout value or if you provide a
         * timeout value of exactly 0s and 0ns, then this call will block
         * without any timeout!
         *
         * @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!
         *
         * @e Note: If you don't provide a timeout value or if you provide a
         * timeout value of exactly 0s and 0ns, then this call will block
         * without any timeout!
         *
         * @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. (Note the condition will not be locked for the calling
         * thread after this method returns!)
         *
         * @param bCondition - new condition
         */
        void Set(bool bCondition);

        /**
         * Returns the current boolean state of this condition object.
         * @e Caution: this method is not thread safe! If you need to use
         * the condition state in a thread critical context you must call
         * @c Lock() and @c Unlock() respectively by yourself!
         */
        bool GetUnsafe();

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

} // namespace LinuxSampler

#endif // __CONDITION_H__
1	/***************************************************************************
2	* *
3	* LinuxSampler - modular, streaming capable sampler *
4	* *
5	* Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck *
6	* Copyright (C) 2005 - 2007 Christian Schoenebeck *
7	* *
8	* This program is free software; you can redistribute it and/or modify *
9	* it under the terms of the GNU General Public License as published by *
10	* the Free Software Foundation; either version 2 of the License, or *
11	* (at your option) any later version. *
12	* *
13	* This program is distributed in the hope that it will be useful, *
14	* but WITHOUT ANY WARRANTY; without even the implied warranty of *
15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
16	* GNU General Public License for more details. *
17	* *
18	* You should have received a copy of the GNU General Public License *
19	* along with this program; if not, write to the Free Software *
20	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, *
21	* MA 02111-1307 USA *
22	***************************************************************************/
23
24	#ifndef __CONDITION_H__
25	#define __CONDITION_H__
26
27	#include "Mutex.h"
28
29	namespace LinuxSampler {
30
31	/**
32	* Thread safe boolean condition.
33	*
34	* This is not meant to be used for real time operation!
35	*/
36	class Condition : public Mutex {
37	public:
38	/**
39	* Constructor
40	*
41	* @param bInitialCondition - optional: starting condition
42	* (default = false)
43	*/
44	Condition(bool bInitialCondition = false);
45
46	/**
47	* Destructor
48	*/
49	virtual ~Condition();
50
51	/**
52	* Blocks the calling thread if current condition equals
53	* \a bCondition, in this case the calling thread will be blocked
54	* until condition turns. Upon successful return the Condition
55	* object is locked, so the calling thread can safely run it's
56	* critical section and has to explicitly call Unlock() right after
57	* it left it's critcal section.
58	*
59	* @e Note: If you don't provide a timeout value or if you provide a
60	* timeout value of exactly 0s and 0ns, then this call will block
61	* without any timeout!
62	*
63	* @param bCondition - block in case of this condition
64	* @param TimeoutSeconds - optional: max. wait time in seconds
65	* (default: 0s)
66	* @param TimeoutNanoSeconds - optional: max wait time in nano
67	* seconds (default: 0ns)
68	* @returns 0 on success, a value less than 0 if timeout exceeded
69	*/
70	int WaitIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);
71
72	/**
73	* Same as WaitIf(), except that WaitAndUnlockIf() will unlock the
74	* Condition object, so only use this call if you don't need to
75	* enter a thread critical section, otherwise use WaitIf() instead!
76	*
77	* @e Note: If you don't provide a timeout value or if you provide a
78	* timeout value of exactly 0s and 0ns, then this call will block
79	* without any timeout!
80	*
81	* @param bCondition - block in case of this condition
82	* @param TimeoutSeconds - optional: max. wait time in seconds
83	* (default: 0s)
84	* @param TimeoutNanoSeconds - optional: max wait time in nano
85	* seconds (default: 0ns)
86	* @returns 0 on success, a value less than 0 if timeout exceeded
87	* @see WaitIf()
88	*/
89	int WaitAndUnlockIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L);
90
91	/**
92	* Set Condition object to \a bCondition. Upon change of the
93	* condition, other threads waiting for \a bCondition will be
94	* awakened. (Note the condition will not be locked for the calling
95	* thread after this method returns!)
96	*
97	* @param bCondition - new condition
98	*/
99	void Set(bool bCondition);
100
101	/**
102	* Returns the current boolean state of this condition object.
103	* @e Caution: this method is not thread safe! If you need to use
104	* the condition state in a thread critical context you must call
105	* @c Lock() and @c Unlock() respectively by yourself!
106	*/
107	bool GetUnsafe();
108
109	protected:
110	pthread_cond_t __posix_true_condition;
111	pthread_cond_t __posix_false_condition;
112	bool bCondition;
113	};
114
115	} // namespace LinuxSampler
116
117	#endif // __CONDITION_H__