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#ifndef _sys_Semaphore_h
#define _sys_Semaphore_h
/*
*
* Copyright (c) 2006 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include "qpid/sys/Monitor.h"
namespace qpid {
namespace sys {
class Semaphore
{
public:
Semaphore(uint c = 1) : count(c) {}
void lock() { acquire(); }
void unlock() { release(); }
bool trylock() { return tryAcquire(); }
bool tryAcquire()
{
Monitor::ScopedLock l(monitor);
if (count) {
count--;
return true;
} else {
return false;
}
}
void acquire()
{
Monitor::ScopedLock l(monitor);
while (count == 0) monitor.wait();
count--;
}
void release(uint n)
{
Monitor::ScopedLock l(monitor);
if (count==0) monitor.notifyAll();
count+=n;
}
void release()
{
release(1);
}
void forceLock()
{
Monitor::ScopedLock l(monitor);
count = 0;
}
private:
Monitor monitor;
uint count;
};
}}
#endif /*!_sys_Semaphore_h*/
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