Mercurial > projects > ldc
view druntime/src/common/core/sync/barrier.d @ 1458:e0b2d67cfe7c
Added druntime (this should be removed once it works).
author | Robert Clipsham <robert@octarineparrot.com> |
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date | Tue, 02 Jun 2009 17:43:06 +0100 |
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/** * The barrier module provides a primitive for synchronizing the progress of * a group of threads. * * Copyright: Copyright Sean Kelly 2005 - 2009. * License: <a href="http://www.boost.org/LICENSE_1_0.txt>Boost License 1.0</a>. * Authors: Sean Kelly * * Copyright Sean Kelly 2005 - 2009. * 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) */ module core.sync.barrier; public import core.sync.exception; private import core.sync.condition; private import core.sync.mutex; version( Win32 ) { private import core.sys.windows.windows; } else version( Posix ) { private import core.stdc.errno; private import core.sys.posix.pthread; } //////////////////////////////////////////////////////////////////////////////// // Barrier // // void wait(); //////////////////////////////////////////////////////////////////////////////// /** * This class represents a barrier across which threads may only travel in * groups of a specific size. */ class Barrier { //////////////////////////////////////////////////////////////////////////// // Initialization //////////////////////////////////////////////////////////////////////////// /** * Initializes a barrier object which releases threads in groups of limit * in size. * * Params: * limit = The number of waiting threads to release in unison. * * Throws: * SyncException on error. */ this( uint limit ) in { assert( limit > 0 ); } body { m_lock = new Mutex; m_cond = new Condition( m_lock ); m_group = 0; m_limit = limit; m_count = limit; } //////////////////////////////////////////////////////////////////////////// // General Actions //////////////////////////////////////////////////////////////////////////// /** * Wait for the pre-determined number of threads and then proceed. * * Throws: * SyncException on error. */ void wait() { synchronized( m_lock ) { uint group = m_group; if( --m_count == 0 ) { m_group++; m_count = m_limit; m_cond.notifyAll(); } while( group == m_group ) m_cond.wait(); } } private: Mutex m_lock; Condition m_cond; uint m_group; uint m_limit; uint m_count; } //////////////////////////////////////////////////////////////////////////////// // Unit Tests //////////////////////////////////////////////////////////////////////////////// version( unittest ) { private import core.thread; unittest { int numThreads = 10; auto barrier = new Barrier( numThreads ); auto synInfo = new Object; int numReady = 0; int numPassed = 0; void threadFn() { synchronized( synInfo ) { ++numReady; } barrier.wait(); synchronized( synInfo ) { ++numPassed; } } auto group = new ThreadGroup; for( int i = 0; i < numThreads; ++i ) { group.create( &threadFn ); } group.joinAll(); assert( numReady == numThreads && numPassed == numThreads ); } }