Mercurial > hg > vamp-build-and-test
diff DEPENDENCIES/generic/include/boost/thread/latch.hpp @ 16:2665513ce2d3
Add boost headers
author | Chris Cannam |
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date | Tue, 05 Aug 2014 11:11:38 +0100 |
parents | |
children | c530137014c0 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/DEPENDENCIES/generic/include/boost/thread/latch.hpp Tue Aug 05 11:11:38 2014 +0100 @@ -0,0 +1,167 @@ +// Distributed under the Boost Software License, Version 1.0. (See +// accompanying file LICENSE_1_0.txt or copy at +// http://www.boost.org/LICENSE_1_0.txt) +// (C) Copyright 2013 Vicente J. Botet Escriba + +#ifndef BOOST_THREAD_LATCH_HPP +#define BOOST_THREAD_LATCH_HPP + +#include <boost/thread/detail/config.hpp> +#include <boost/thread/detail/delete.hpp> +#include <boost/thread/detail/counter.hpp> + +#include <boost/thread/mutex.hpp> +#include <boost/thread/lock_types.hpp> +#include <boost/thread/condition_variable.hpp> +#include <boost/chrono/duration.hpp> +#include <boost/chrono/time_point.hpp> +#include <boost/assert.hpp> + +#include <boost/config/abi_prefix.hpp> + +namespace boost +{ + class latch + { + /// @Requires: count_ must be greater than 0 + /// Effect: Decrement the count. Unlocks the lock and notify anyone waiting if we reached zero. + /// Returns: true if count_ reached the value 0. + /// @ThreadSafe ensured by the @c lk parameter + bool count_down(unique_lock<mutex> &lk) + /// pre_condition (count_ > 0) + { + BOOST_ASSERT(count_ > 0); + if (--count_ == 0) + { + ++generation_; + lk.unlock(); + cond_.notify_all(); + return true; + } + return false; + } + /// Effect: Decrement the count is > 0. Unlocks the lock notify anyone waiting if we reached zero. + /// Returns: true if count_ is 0. + /// @ThreadSafe ensured by the @c lk parameter + bool try_count_down(unique_lock<mutex> &lk) + { + if (count_ > 0) + { + return count_down(lk); + } + return true; + } + public: + BOOST_THREAD_NO_COPYABLE( latch) + + /// Constructs a latch with a given count. + latch(std::size_t count) : + count_(count), generation_(0) + { + } + + /// Destructor + /// Precondition: No threads are waiting or invoking count_down on @c *this. + + ~latch() + { + + } + + /// Blocks until the latch has counted down to zero. + void wait() + { + boost::unique_lock<boost::mutex> lk(mutex_); + std::size_t generation(generation_); + cond_.wait(lk, detail::not_equal(generation, generation_)); + } + + /// @return true if the internal counter is already 0, false otherwise + bool try_wait() + { + boost::unique_lock<boost::mutex> lk(mutex_); + return (count_ == 0); + } + + /// try to wait for a specified amount of time is elapsed. + /// @return whether there is a timeout or not. + template <class Rep, class Period> + cv_status wait_for(const chrono::duration<Rep, Period>& rel_time) + { + boost::unique_lock<boost::mutex> lk(mutex_); + std::size_t generation(generation_); + return cond_.wait_for(lk, rel_time, detail::not_equal(generation, generation_)) + ? cv_status::no_timeout + : cv_status::timeout; + } + + /// try to wait until the specified time_point is reached + /// @return whether there were a timeout or not. + template <class Clock, class Duration> + cv_status wait_until(const chrono::time_point<Clock, Duration>& abs_time) + { + boost::unique_lock<boost::mutex> lk(mutex_); + std::size_t generation(generation_); + return cond_.wait_until(lk, abs_time, detail::not_equal(generation, generation_)) + ? cv_status::no_timeout + : cv_status::timeout; + } + + /// Decrement the count and notify anyone waiting if we reach zero. + /// @Requires count must be greater than 0 + void count_down() + { + boost::unique_lock<boost::mutex> lk(mutex_); + count_down(lk); + } + /// Effect: Decrement the count if it is > 0 and notify anyone waiting if we reached zero. + /// Returns: true if count_ was 0 or reached 0. + bool try_count_down() + { + boost::unique_lock<boost::mutex> lk(mutex_); + return try_count_down(lk); + } + void signal() + { + count_down(); + } + + /// Decrement the count and notify anyone waiting if we reach zero. + /// Blocks until the latch has counted down to zero. + /// @Requires count must be greater than 0 + void count_down_and_wait() + { + boost::unique_lock<boost::mutex> lk(mutex_); + std::size_t generation(generation_); + if (count_down(lk)) + { + return; + } + cond_.wait(lk, detail::not_equal(generation, generation_)); + } + void sync() + { + count_down_and_wait(); + } + + /// Reset the counter + /// #Requires This method may only be invoked when there are no other threads currently inside the count_down_and_wait() method. + void reset(std::size_t count) + { + boost::lock_guard<boost::mutex> lk(mutex_); + //BOOST_ASSERT(count_ == 0); + count_ = count; + } + + private: + mutex mutex_; + condition_variable cond_; + std::size_t count_; + std::size_t generation_; + }; + +} // namespace boost + +#include <boost/config/abi_suffix.hpp> + +#endif