// Copyright (C) 2002-2003 // David Moore, William E. Kempf // Copyright (C) 2007-8 Anthony Williams // // 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) #ifndef BOOST_BARRIER_JDM030602_HPP #define BOOST_BARRIER_JDM030602_HPP #include <boost/thread/detail/config.hpp> #include <boost/throw_exception.hpp> #include <boost/thread/mutex.hpp> #include <boost/thread/condition_variable.hpp> #include <string> #include <stdexcept> #include <boost/config/abi_prefix.hpp> namespace boost { class barrier { public: barrier(unsigned int count) : m_threshold(count), m_count(count), m_generation(0) { if (count == 0) boost::throw_exception(std::invalid_argument("count cannot be zero.")); } bool wait() { boost::mutex::scoped_lock lock(m_mutex); unsigned int gen = m_generation; if (--m_count == 0) { m_generation++; m_count = m_threshold; m_cond.notify_all(); return true; } while (gen == m_generation) m_cond.wait(lock); return false; } private: mutex m_mutex; condition_variable m_cond; unsigned int m_threshold; unsigned int m_count; unsigned int m_generation; }; } // namespace boost #include <boost/config/abi_suffix.hpp> #endif