/[svn]/linuxsampler/trunk/src/common/ConditionServer.h
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revision 1763 by schoenebeck, Sun Oct 14 22:00:17 2007 UTC revision 1764 by persson, Sat Sep 6 14:55:18 2008 UTC
# Line 3  Line 3 
3   *   LinuxSampler - modular, streaming capable sampler                     *   *   LinuxSampler - modular, streaming capable sampler                     *
4   *                                                                         *   *                                                                         *
5   *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *   *   Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck   *
6   *   Copyright (C) 2005 - 2007 Christian Schoenebeck                       *   *   Copyright (C) 2005 - 2008 Christian Schoenebeck                       *
7   *                                                                         *   *                                                                         *
8   *   This program is free software; you can redistribute it and/or modify  *   *   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  *   *   it under the terms of the GNU General Public License as published by  *
# Line 25  Line 25 
25  #define __CONDITIONSERVER_H__  #define __CONDITIONSERVER_H__
26    
27  #include "Mutex.h"  #include "Mutex.h"
28  #include "Condition.h"  #include "SynchronizedConfig.h"
29    
30  namespace LinuxSampler {  namespace LinuxSampler {
31    
# Line 41  namespace LinuxSampler { Line 41  namespace LinuxSampler {
41   * method will immediately return if the current condition already equals   * method will immediately return if the current condition already equals
42   * the desired condition given with Push(), if it's not equal then Push()   * the desired condition given with Push(), if it's not equal then Push()
43   * will cause a request to change the condition and will block until the   * will cause a request to change the condition and will block until the
44   * condition actually changed, which happens when the RTT calls the Pop()   * condition actually changed, which happens when the RTT is outside its
45   * method, which will also return the new condition to the RTT.   * critical region, or has called the Pop() method, which will also return
46     * the new condition to the RTT.
47   *   *
48   * Advantage of this technique is that the RTT doesn't has to execute system   * Advantage of this technique is that the RTT doesn't has to execute system
49   * calls whenever it wants to check for a condition change, the RTT only has   * calls whenever it wants to check for a condition change. Disadvantage on
50   * to execute one system call when the condition changed. Disadvantage on   * the other hand is that the NRTTs might be blocked for some time, but this
51   * the other hand is that the NRTTs might be blocked for a long time, but   * is usually unproblematic for NRTTs.
  * this is usually unproblematic for NRTTs.  
52   */   */
53  class ConditionServer {  class ConditionServer {
54      public:      public:
# Line 62  class ConditionServer { Line 62  class ConditionServer {
62           * equals \a bCondition, then this method will immediately return,           * equals \a bCondition, then this method will immediately return,
63           * if not it will block the calling thread until the condition           * if not it will block the calling thread until the condition
64           * actually changed to the requested condition (which happens when           * actually changed to the requested condition (which happens when
65           * Pop() is called by the real time thread). If there are multiple           * Pop() has been called by the real time thread, or when the real
66             * time thread is outside its critical region). If there are multiple
67           * non real time threads calling Push() only one by one will be           * non real time threads calling Push() only one by one will be
68           * served, all others blocked meanwhile. When the calling thread           * served, all others blocked meanwhile. When the calling thread
69           * returns from Push() the Push() method will still be blocked           * returns from Push() the Push() method will still be blocked
# Line 119  class ConditionServer { Line 120  class ConditionServer {
120          // method for real time thread (1 RTT)          // method for real time thread (1 RTT)
121    
122          /**          /**
123           * Should frequently be called by the real time thread (RTT) to           * Should be called by the real time thread (RTT) at the
124           * check for a condition change. If a NRTT requested a condition           * beginning of the critical region to check for a condition
125           * change by calling Push() ot PushAndUnlock() the NRTT wil be           * change. If an NRTT requested a condition change by calling
126           * blocked until the RTT calls Pop(), means until the RTT actually           * Push() or PushAndUnlock() the NRTT will be blocked until
127           * knows about the condition change.           * it knows that the RTT will not go into its critical region
128             * without being notified about the condition change.
129           *           *
130           * @returns  current condition           * @returns  current condition
131           */           */
132          bool Pop();          bool Pop() {
133                return Reader.Lock();
134            }
135    
136            /**
137             * Should be called by the real time thread (RTT) at the end of
138             * the critical region.
139             */
140            void RttDone() {
141                Reader.Unlock();
142            }
143    
144      protected:      protected:
145          bool      bConditionQuick;          SynchronizedConfig<bool> Condition;
146          bool      bChangeRequest;          SynchronizedConfig<bool>::Reader Reader;
147          bool      bOldCondition;          bool      bOldCondition;
         Condition SyncCondition;  
148          Mutex     PushMutex;          Mutex     PushMutex;
149  };  };
150    
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