http://stxxl.sourceforge.net
<dementiev@mpi-sb.mpg.de>
<beckmann@cs.uni-frankfurt.de>
http://www.boost.org/LICENSE_1_0.txt
#ifndef STXXL_STATE_HEADER
#define STXXL_STATE_HEADER
#ifdef STXXL_BOOST_THREADS
#include <boost/thread/mutex.hpp>
#include <boost/thread/condition.hpp>
#else
#include <pthread.h>
#endif
#include <stxxl/bits/noncopyable.h>
#include <stxxl/bits/common/error_handling.h>
__STXXL_BEGIN_NAMESPACE
template <typename Tp = int>
class state : private noncopyable
{
typedef Tp value_type;
#ifdef STXXL_BOOST_THREADS
boost::mutex mutex;
boost::condition cond;
#else
pthread_mutex_t mutex;
pthread_cond_t cond;
#endif
value_type _state;
public:
state(value_type s) : _state(s)
{
#ifndef STXXL_BOOST_THREADS
check_pthread_call(pthread_mutex_init(&mutex, NULL));
check_pthread_call(pthread_cond_init(&cond, NULL));
#endif
}
~state()
{
#ifndef STXXL_BOOST_THREADS
int res = pthread_mutex_trylock(&mutex);
if (res == 0 || res == EBUSY) {
check_pthread_call(pthread_mutex_unlock(&mutex));
} else
stxxl_function_error(resource_error);
check_pthread_call(pthread_mutex_destroy(&mutex));
check_pthread_call(pthread_cond_destroy(&cond));
#endif
}
void set_to(value_type new_state)
{
#ifdef STXXL_BOOST_THREADS
boost::mutex::scoped_lock Lock(mutex);
_state = new_state;
Lock.unlock();
cond.notify_all();
#else
check_pthread_call(pthread_mutex_lock(&mutex));
_state = new_state;
check_pthread_call(pthread_mutex_unlock(&mutex));
check_pthread_call(pthread_cond_broadcast(&cond));
#endif
}
void wait_for(value_type needed_state)
{
#ifdef STXXL_BOOST_THREADS
boost::mutex::scoped_lock Lock(mutex);
while (needed_state != _state)
cond.wait(Lock);
#else
check_pthread_call(pthread_mutex_lock(&mutex));
while (needed_state != _state)
check_pthread_call(pthread_cond_wait(&cond, &mutex));
check_pthread_call(pthread_mutex_unlock(&mutex));
#endif
}
value_type operator () ()
{
#ifdef STXXL_BOOST_THREADS
boost::mutex::scoped_lock Lock(mutex);
return _state;
#else
value_type res;
check_pthread_call(pthread_mutex_lock(&mutex));
res = _state;
check_pthread_call(pthread_mutex_unlock(&mutex));
return res;
#endif
}
};
__STXXL_END_NAMESPACE
#endif