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Diffstat (limited to 'dep/include/zthread/BiasedReadWriteLock.h')
| -rw-r--r-- | dep/include/zthread/BiasedReadWriteLock.h | 320 |
1 files changed, 0 insertions, 320 deletions
diff --git a/dep/include/zthread/BiasedReadWriteLock.h b/dep/include/zthread/BiasedReadWriteLock.h deleted file mode 100644 index f1877bb116b..00000000000 --- a/dep/include/zthread/BiasedReadWriteLock.h +++ /dev/null @@ -1,320 +0,0 @@ -/* - * 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 __ZTBIASEDREADWRITELOCK_H__ -#define __ZTBIASEDREADWRITELOCK_H__ - -#include "zthread/ReadWriteLock.h" -#include "zthread/Condition.h" -#include "zthread/Guard.h" -#include "zthread/FastMutex.h" - -namespace ZThread { - - /** - * @class BiasedReadWriteLock - * - * @author Eric Crahen <http://www.code-foo.com> - * @date <2003-07-16T10:22:34-0400> - * @version 2.2.7 - * - * A BiasedReadWriteLock has a bias toward writers. It will prefer read-write access over - * read-only access when many threads are contending for access to either Lockable this - * ReadWriteLock provides. - * - * @see ReadWriteLock - */ - class BiasedReadWriteLock : public ReadWriteLock { - - FastMutex _lock; - Condition _condRead; - Condition _condWrite; - - volatile int _activeWriters; - volatile int _activeReaders; - - volatile int _waitingReaders; - volatile int _waitingWriters; - - //! @class ReadLock - class ReadLock : public Lockable { - - BiasedReadWriteLock& _rwlock; - - public: - - ReadLock(BiasedReadWriteLock& rwlock) : _rwlock(rwlock) {} - - virtual ~ReadLock() {} - - virtual void acquire() { - _rwlock.beforeRead(); - } - - virtual bool tryAcquire(unsigned long timeout) { - return _rwlock.beforeReadAttempt(timeout); - } - - virtual void release() { - _rwlock.afterRead(); - } - - }; - - //! @class WriteLock - class WriteLock : public Lockable { - - BiasedReadWriteLock& _rwlock; - - public: - - WriteLock(BiasedReadWriteLock& rwlock) : _rwlock(rwlock) {} - - virtual ~WriteLock() {} - - - virtual void acquire() { - _rwlock.beforeWrite(); - } - - virtual bool tryAcquire(unsigned long timeout) { - return _rwlock.beforeWriteAttempt(timeout); - } - - virtual void release() { - _rwlock.afterWrite(); - } - - }; - - friend class ReadLock; - friend class WriteLock; - - ReadLock _rlock; - WriteLock _wlock; - - public: - - /** - * Create a BiasedReadWriteLock - * - * @exception Initialization_Exception thrown if resources could not be - * allocated for this object. - */ - BiasedReadWriteLock() : _condRead(_lock), _condWrite(_lock), _rlock(*this), _wlock(*this) { - - _activeWriters = 0; - _activeReaders = 0; - - _waitingReaders = 0; - _waitingWriters = 0; - - } - - //! Destroy this ReadWriteLock - virtual ~BiasedReadWriteLock() {} - - /** - * @see ReadWriteLock::getReadLock() - */ - virtual Lockable& getReadLock() { return _rlock; } - - /** - * @see ReadWriteLock::getWriteLock() - */ - virtual Lockable& getWriteLock() { return _wlock; } - - - protected: - - void beforeRead() { - - Guard<FastMutex> guard(_lock); - - ++_waitingReaders; - - while(!allowReader()) { - - try { - - // wait - _condRead.wait(); - - } catch(...) { - - --_waitingReaders; - throw; - - } - - } - - --_waitingReaders; - ++_activeReaders; - - } - - bool beforeReadAttempt(unsigned long timeout) { - - Guard<FastMutex> guard(_lock); - bool result = false; - - ++_waitingReaders; - - while(!allowReader()) { - - try { - - result = _condRead.wait(timeout); - - } catch(...) { - - --_waitingReaders; - throw; - - } - - } - - --_waitingReaders; - ++_activeReaders; - - return result; - } - - - void afterRead() { - - bool wakeReader = false; - bool wakeWriter = false; - - { - - Guard<FastMutex> guard(_lock); - - --_activeReaders; - - wakeReader = (_waitingReaders > 0); - wakeWriter = (_waitingWriters > 0); - - } - - if(wakeWriter) - _condWrite.signal(); - - else if(wakeReader) - _condRead.signal(); - - } - - void beforeWrite() { - - Guard<FastMutex> guard(_lock); - - ++_waitingWriters; - - while(!allowWriter()) { - - try { - - _condWrite.wait(); - - } catch(...) { - - --_waitingWriters; - throw; - - } - - } - - --_waitingWriters; - ++_activeWriters; - - } - - bool beforeWriteAttempt(unsigned long timeout) { - - Guard<FastMutex> guard(_lock); - bool result = false; - - ++_waitingWriters; - - while(!allowWriter()) { - - try { - - result = _condWrite.wait(timeout); - - } catch(...) { - - --_waitingWriters; - throw; - } - - } - - --_waitingWriters; - ++_activeWriters; - - return result; - - } - - void afterWrite() { - - bool wakeReader = false; - bool wakeWriter = false; - - { - - Guard<FastMutex> guard(_lock); - - --_activeWriters; - - wakeReader = (_waitingReaders > 0); - wakeWriter = (_waitingWriters > 0); - - } - - if(wakeWriter) - _condWrite.signal(); - - else if(wakeReader) - _condRead.signal(); - - } - - bool allowReader() { - return (_activeWriters == 0); - } - - bool allowWriter() { - return (_activeWriters == 0 && _activeReaders == 0); - } - - }; - -}; // __ZTBIASEDREADWRITELOCK_H__ - -#endif - |