学步园

class CReadWriteSection<br /> {<br /> public:<br /> CReadWriteSection() {<br /> InitializeCriticalSection(&_csEnterRead);<br /> InitializeCriticalSection(&_csWriter);<br /> _lReaders = -1;<br /> }<br /> ~CReadWriteSection() {<br /> DeleteCriticalSection(&_csEnterRead);<br /> DeleteCriticalSection(&_csWriter);<br /> }<br /> void EnterRead()<br /> {<br /> EnterCriticalSection(&_csEnterRead);<br /> if (!InterlockedIncrement(&_lReaders))<br /> EnterCriticalSection(&_csWriter);<br /> LeaveCriticalSection(&_csEnterRead);<br /> }<br /> void LeaveRead()<br /> {<br /> if (InterlockedDecrement(&_lReaders)<0)<br /> LeaveCriticalSection(&_csWriter);<br /> }<br /> void EnterWrite()<br /> {<br /> EnterCriticalSection(&_csEnterRead);<br /> EnterCriticalSection(&_csWriter);<br /> }<br /> void LeaveWrite()<br /> {<br /> LeaveCriticalSection(&_csWriter);<br /> LeaveCriticalSection(&_csEnterRead);<br /> }<br /> // Note that readers will continue reading underneath this critical section<br /> CRITICAL_SECTION *GetPcs()<br /> {<br /> return &_csEnterRead;<br /> }<br /> private:<br /> CRITICAL_SECTION _csEnterRead;<br /> CRITICAL_SECTION _csWriter;<br /> LONG _lReaders;<br /> };<br /> class CReadLock<br /> {<br /> public:<br /> CReadLock(CReadWriteSection & crws) { (_prws = &crws)->EnterRead(); }<br /> ~CReadLock() { _prws->LeaveRead(); }<br /> private:<br /> CReadWriteSection * _prws;<br /> };<br /> class CWriteLock<br /> {<br /> public:<br /> CWriteLock(CReadWriteSection & crws) { (_prws = &crws)->EnterWrite(); }<br /> ~CWriteLock() { _prws->LeaveWrite(); }<br /> private:<br /> CReadWriteSection * _prws;<br /> };<br /> #define LOCK_READ(crws) CReadLock crws##_readlock(crws)<br /> #define LOCK_WRITE(crws) CWriteLock crws##_writelock(crws)