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107 lines
3.6 KiB
107 lines
3.6 KiB
4 months ago
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#ifndef _DESEMAPHORE_HPP
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#define _DESEMAPHORE_HPP
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/*-------------------------------------------------------------------------
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* drawElements C++ Base Library
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* -----------------------------
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*
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* Copyright 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*//*!
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* \file
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* \brief deSemaphore C++ wrapper.
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*//*--------------------------------------------------------------------*/
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#include "deDefs.hpp"
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#include "deSemaphore.h"
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namespace de
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{
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/*--------------------------------------------------------------------*//*!
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* \brief Semaphore
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*
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* Semaphore provides standard semaphore functionality.
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*
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* Semaphore is thread-safe counter that can be used to control access
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* to a set of resources. The count can be incremented and decremented.
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* When decrementing causes counter to reach negative value, it will
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* block until increment has been called from an another thread.
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*//*--------------------------------------------------------------------*/
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class Semaphore
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{
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public:
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Semaphore (int initialValue, deUint32 flags = 0);
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~Semaphore (void);
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void increment (void) throw();
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void decrement (void) throw();
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bool tryDecrement (void) throw();
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private:
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Semaphore (const Semaphore& other); // Not allowed!
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Semaphore& operator= (const Semaphore& other); // Not allowed!
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deSemaphore m_semaphore;
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};
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// Inline implementations.
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/*--------------------------------------------------------------------*//*!
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* \brief Increment semaphore count.
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*
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* Incremeting increases semaphore value by 1. If a value is currently
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* negative (there is a thread waiting in decrement) the waiting thread
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* will be resumed.
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*
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* Incrementing semaphore will never block.
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*//*--------------------------------------------------------------------*/
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inline void Semaphore::increment (void) throw()
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{
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deSemaphore_increment(m_semaphore);
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}
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/*--------------------------------------------------------------------*//*!
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* \brief Decrement semaphore count.
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*
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* Decrementing decreases semaphore value by 1. If resulting value is negative
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* (only -1 is possible) decrement() will block until the value is again 0
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* (increment() has been called).
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*
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* If there is an another thread waiting in decrement(), the current thread
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* will block until other thread(s) have been resumed.
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*//*--------------------------------------------------------------------*/
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inline void Semaphore::decrement (void) throw()
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{
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deSemaphore_decrement(m_semaphore);
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}
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/*--------------------------------------------------------------------*//*!
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* \brief Try to decrement semaphore value.
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* \return true if decrementing was successful without blocking, false
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* otherwise
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*
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* This function will never block, i.e. it will return false if decrementing
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* semaphore counter would result in negative value or there is already
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* one or more threads waiting for this semaphore.
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*//*--------------------------------------------------------------------*/
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inline bool Semaphore::tryDecrement (void) throw()
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{
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return deSemaphore_tryDecrement(m_semaphore) == DE_TRUE;
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}
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} // de
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#endif // _DESEMAPHORE_HPP
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