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Diffstat (limited to 'dep/include/zthread/CountingSemaphore.h')
-rw-r--r-- | dep/include/zthread/CountingSemaphore.h | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/dep/include/zthread/CountingSemaphore.h b/dep/include/zthread/CountingSemaphore.h new file mode 100644 index 00000000000..f580a65f726 --- /dev/null +++ b/dep/include/zthread/CountingSemaphore.h @@ -0,0 +1,138 @@ +/* + * Copyright (c) 2005, Eric Crahen + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is furnished + * to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in all + * copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, + * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + * + */ + +#ifndef __ZTCOUNTINGSEMAPHORE_H__ +#define __ZTCOUNTINGSEMAPHORE_H__ + +#include "zthread/Lockable.h" +#include "zthread/NonCopyable.h" + +namespace ZThread { + + class FifoSemaphoreImpl; + + /** + * @class CountingSemaphore + * @author Eric Crahen <http://www.code-foo.com> + * @date <2003-07-16T15:26:18-0400> + * @version 2.2.1 + * + * A CountingSemaphore is an owner-less Lockable object. + * + * It differs from a normal Semaphore in that there is no upper bound on the count + * and it will not throw an exception because a maximum value has been exceeded. + * + * @see Semaphore + * + * Threads blocked on a CountingSemaphore are resumed in FIFO order. + */ + class ZTHREAD_API CountingSemaphore : public Lockable, private NonCopyable { + + FifoSemaphoreImpl* _impl; + + public: + + /** + * Create a new CountingSemaphore. + * + * @param count - initial count + */ + CountingSemaphore(int initialCount = 0); + + //! Destroy the CountingSemaphore + virtual ~CountingSemaphore(); + + /** + * <i>Provided to reflect the traditional Semaphore semantics</i> + * + * @see acquire() + */ + void wait(); + + + /** + * <i>Provided to reflect the traditional Semaphore semantics</i> + * + * @see tryAcquire(unsigned long timeout) + */ + bool tryWait(unsigned long timeout); + + /** + * <i>Provided to reflect the traditional Semaphore semantics</i> + * + * @see release() + */ + void post(); + + + /** + * Get the current count of the semaphore. + * + * This value may change immediately after this function returns to the calling thread. + * + * @return <em>int</em> count + */ + virtual int count(); + + /** + * Decrement the count, blocking that calling thread if the count becomes 0 or + * less than 0. The calling thread will remain blocked until the count is + * raised above 0, an exception is thrown or the given amount of time expires. + * + * @param timeout maximum amount of time (milliseconds) this method could block + * + * @return + * - <em>true</em> if the Semaphore was acquired before <i>timeout</i> milliseconds elapse. + * - <em>false</em> otherwise. + * + * @exception Interrupted_Exception thrown when the calling thread is interrupted. + * A thread may be interrupted at any time, prematurely ending any wait. + * + * @see Lockable::tryAcquire(unsigned long timeout) + */ + virtual bool tryAcquire(unsigned long timeout); + + /** + * Decrement the count, blocking that calling thread if the count becomes 0 or + * less than 0. The calling thread will remain blocked until the count is + * raised above 0 or if an exception is thrown. + * + * @exception Interrupted_Exception thrown when the calling thread is interrupted. + * A thread may be interrupted at any time, prematurely ending any wait. + * + * @see Lockable::acquire() + */ + virtual void acquire(); + + /** + * Increment the count, unblocking one thread if count is positive. + * + * @see Lockable::release() + */ + virtual void release(); + + }; + + +} // namespace ZThread + +#endif // __ZTCOUNTINGSEMAPHORE_H__ |