82 lines
1.8 KiB
Text
82 lines
1.8 KiB
Text
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/**
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* PANDA 3D SOFTWARE
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* Copyright (c) Carnegie Mellon University. All rights reserved.
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*
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* All use of this software is subject to the terms of the revised BSD
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* license. You should have received a copy of this license along
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* with this source code in a file named "LICENSE."
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*
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* @file psemaphore.I
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* @author drose
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* @date 2008-10-13
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*/
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/**
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*
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*/
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INLINE Semaphore::
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Semaphore(int initial_count) :
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_lock("Semaphore::_lock"),
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_cvar(_lock),
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_count(initial_count)
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{
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nassertv(_count >= 0);
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}
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/**
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* Decrements the internal count. If the count was already at zero, blocks
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* until the count is nonzero, then decrements it.
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*/
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INLINE void Semaphore::
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acquire() {
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TAU_PROFILE("void Semaphore::acquire()", " ", TAU_USER);
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MutexHolder holder(_lock);
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nassertv(_count >= 0);
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while (_count <= 0) {
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_cvar.wait();
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}
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--_count;
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}
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/**
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* If the semaphore can be acquired without blocking, does so and returns
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* true. Otherwise, returns false.
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*/
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INLINE bool Semaphore::
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try_acquire() {
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TAU_PROFILE("void Semaphore::acquire(bool)", " ", TAU_USER);
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MutexHolder holder(_lock);
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nassertr(_count >= 0, false);
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if (_count <= 0) {
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return false;
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}
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--_count;
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return true;
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}
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/**
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* Increments the semaphore's internal count. This may wake up another thread
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* blocked on acquire().
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*
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* Returns the count of the semaphore upon release.
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*/
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INLINE int Semaphore::
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release() {
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TAU_PROFILE("void Semaphore::release()", " ", TAU_USER);
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MutexHolder holder(_lock);
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++_count;
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_cvar.notify();
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return _count;
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}
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/**
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* Returns the current semaphore count. Note that this call is not thread-
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* safe (the count may change at any time).
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*/
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INLINE int Semaphore::
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get_count() const {
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TAU_PROFILE("void Semaphore::get_count()", " ", TAU_USER);
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MutexHolder holder(_lock);
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return _count;
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}
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