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/*************************************************************************** |
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* * |
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* LinuxSampler - modular, streaming capable sampler * |
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* * |
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* Copyright (C) 2003, 2004 by Benno Senoner and Christian Schoenebeck * |
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* Copyright (C) 2005 - 2017 Christian Schoenebeck * |
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* * |
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* This program is free software; you can redistribute it and/or modify * |
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* it under the terms of the GNU General Public License as published by * |
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* the Free Software Foundation; either version 2 of the License, or * |
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* (at your option) any later version. * |
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* * |
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* This program is distributed in the hope that it will be useful, * |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of * |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
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* GNU General Public License for more details. * |
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* * |
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* You should have received a copy of the GNU General Public License * |
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* along with this program; if not, write to the Free Software * |
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, * |
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* MA 02111-1307 USA * |
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***************************************************************************/ |
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|
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#ifndef __CONDITION_H__ |
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#define __CONDITION_H__ |
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|
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#include "Mutex.h" |
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|
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#if defined(WIN32) |
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#include <windows.h> |
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#endif |
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|
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namespace LinuxSampler { |
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|
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#if defined(WIN32) |
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class ConditionInternal; |
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#endif |
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|
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/** |
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* Thread safe boolean condition. |
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* |
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* This is not meant to be used for real time operation! |
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*/ |
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class Condition : public Mutex { |
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public: |
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/** @brief Constructor |
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* |
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* Creates a new thread safe condition variable. |
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* |
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* Note that the default bahavior of the underlying mutex is |
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* @c NON_RECURSIVE by default, because in general if your design |
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* requires the Condition object's lock state to be recursive instead, |
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* then most probably this may result in dead locks or even undefined |
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* behavior, because the underlying OS API for conditions may not be |
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* compatible with recursive mutexes! |
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* |
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* @param bInitialCondition - optional: starting condition |
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* (default = false) |
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* @param mutexType - optional: fundamental behavior of underlying mutex |
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* (default: @c NON_RECURSIVE) |
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*/ |
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Condition(bool bInitialCondition = false, Mutex::type_t mutexType = Mutex::NON_RECURSIVE); |
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|
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/** |
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* Destructor |
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*/ |
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virtual ~Condition(); |
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|
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/** |
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* Blocks the calling thread if current condition equals |
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* \a bCondition, in this case the calling thread will be blocked |
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* until condition turns. Upon successful return the Condition |
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* object is locked, so the calling thread can safely run it's |
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* critical section and has to explicitly call Unlock() right after |
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* it left it's critcal section. |
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* |
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* @e Note: If you don't provide a timeout value or if you provide a |
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* timeout value of exactly 0s and 0ns, then this call will block |
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* without any timeout, or in other words: @e infinity! |
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* |
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* @param bCondition - block in case of this condition |
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* @param TimeoutSeconds - optional: max. wait time in seconds |
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* (default: 0s) |
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* @param TimeoutNanoSeconds - optional: max wait time in nano |
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* seconds (default: 0ns) |
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* @returns 0 on success, a value less than 0 if timeout exceeded |
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*/ |
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int WaitIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L); |
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|
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/** |
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* Same as WaitIf(), except that WaitAndUnlockIf() will unlock the |
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* Condition object, so only use this call if you don't need to |
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* enter a thread critical section, otherwise use WaitIf() instead! |
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* |
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* @e Note: If you don't provide a timeout value or if you provide a |
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* timeout value of exactly 0s and 0ns, then this call will block |
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* without any timeout, or in other words: @e infinity! |
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* |
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* @param bCondition - block in case of this condition |
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* @param TimeoutSeconds - optional: max. wait time in seconds |
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* (default: 0s) |
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* @param TimeoutNanoSeconds - optional: max wait time in nano |
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* seconds (default: 0ns) |
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* @returns 0 on success, a value less than 0 if timeout exceeded |
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* @see WaitIf() |
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*/ |
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int WaitAndUnlockIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L); |
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|
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/** |
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* You should use this method instead of WaitIf() in case the calling |
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* thread already owns the Condition object's underlying mutex lock by |
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* previously calling Lock() before. Essentially the only difference to |
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* WaitIf() is that PreLockedWaitIf() does not call Lock() by itself. |
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*/ |
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int PreLockedWaitIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L); |
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|
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/** |
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* You should use this method instead of WaitAndUnlockIf() in case the |
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* calling thread already owns the Condition object's underlying mutex |
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* lock by previously calling Lock() before. Essentially the only |
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* difference to WaitAndUnlockIf() is that PreLockedWaitAndUnlockIf() |
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* does not call Lock() by itself. |
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*/ |
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int PreLockedWaitAndUnlockIf(bool bCondition, long TimeoutSeconds = 0L, long TimeoutNanoSeconds = 0L); |
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|
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/** |
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* Set Condition object to \a bCondition. Upon change of the |
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* condition, other threads waiting for \a bCondition will be |
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* awakened. (Note the condition will not be locked for the calling |
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* thread after this method returns!) |
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* |
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* @param bCondition - new condition |
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*/ |
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void Set(bool bCondition); |
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|
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/** |
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* You should use this method instead of Set() in case the calling |
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* thread already owns the Condition object's underlying mutex lock by |
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* previously calling Lock() before. Essentially the only difference to |
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* Set() is that PreLockedSet() does not call Lock() by itself. |
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*/ |
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void PreLockedSet(bool bCondition); |
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|
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/** |
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* Returns the current boolean state of this condition object. This |
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* method never blocks, it returns immediately and doesn't use any |
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* system calls. |
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* |
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* @e Caution: this method is not thread safe! If you need to use |
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* the condition state in a thread critical context you must call |
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* @c Lock() and @c Unlock() respectively by yourself! |
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*/ |
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bool GetUnsafe(); |
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|
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#ifdef WIN32 |
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/** |
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* Resets the condition. This is only needed on Windows, after |
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* a thread waiting for a condition has been stopped with |
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* StopThread. |
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*/ |
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void Reset(); |
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#endif |
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|
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protected: |
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int WaitIfInternal(bool bLock, bool bCondition, long TimeoutSeconds, long TimeoutNanoSeconds); |
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void SetInternal(bool bLock, bool bCondition); |
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|
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#if defined(WIN32) |
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friend class ConditionInternal; |
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struct win32thread_cond_t { |
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int waiters_count_; ///< Number of waiting threads. |
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CRITICAL_SECTION waiters_count_lock_; ///< Serialize access to <waiters_count_>. |
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HANDLE sema_; ///< Semaphore used to queue up threads waiting for the condition to become signaled. |
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HANDLE waiters_done_; ///< An auto-reset event used by the broadcast/signal thread to wait for all the waiting thread(s) to wake up and be released from the semaphore. |
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size_t was_broadcast_; ///< Keeps track of whether we were broadcasting or signaling. This allows us to optimize the code if we're just signaling. |
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} __win32_true_condition, __win32_false_condition; |
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#else |
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pthread_cond_t __posix_true_condition; |
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pthread_cond_t __posix_false_condition; |
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#endif |
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bool bCondition; |
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}; |
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|
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} // namespace LinuxSampler |
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|
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#endif // __CONDITION_H__ |