使用event与无锁算法实现windows平台上的critical section-Windows教程-爱易网页

使用event与无锁算法实现windows平台上的critical section

日期：2014-05-17　浏览次数：21317 次

使用event与无锁算法实现windows平台下的critical section

//#include "own_cs.h"
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <assert.h>
#include <malloc.h>
#include <stdlib.h>
#include <stdio.h>


struct own_critical_section
{
	long   own_lock_count;          // count of locked thread, -1 means unlock , other means lock.
	HANDLE own_event;               // auto-reset
	DWORD  own_owning_thread_id;    // owner thread of lock
	long   own_recursion_count;     // count of recursion
};


void InitialOwnCriticalSection( own_critical_section** own_cs)
{
	*own_cs = (own_critical_section*)malloc( sizeof( own_critical_section ) );
	(*own_cs)->own_lock_count = -1;
	(*own_cs)->own_event = CreateEventW( NULL, FALSE, FALSE, NULL );
	(*own_cs)->own_owning_thread_id = 0;
	(*own_cs)->own_recursion_count  = 0;
}

void DeleteOwnCriticalSection( own_critical_section* own_cs )
{
	assert( own_cs != NULL );

	CloseHandle( own_cs->own_event );
	free( own_cs );
}

void EnterOwnCriticalSection( own_critical_section* own_cs )
{
	assert( own_cs->own_lock_count>=-1L );
	for ( int spin_count = 0; spin_count < 500; ++ spin_count )
	{//spinlock
		if ( -1L == InterlockedCompareExchange( &own_cs->own_lock_count, -1L, -1L ) )
			break;
		Sleep(0);
	}

	DWORD current_thread_id = ::GetCurrentThreadId();

	if( 0 < InterlockedIncrement( &own_cs->own_lock_count ) &&
		( own_cs->own_owning_thread_id != current_thread_id ) )
	{   
		//locked
		WaitForSingleObject( own_cs->own_event, INFINITE ); 
	}

	own_cs->own_owning_thread_id = current_thread_id;
	++own_cs->own_recursion_count;
}

void LeaveOwnCriticalSection( own_critical_section* own_cs )
{
	assert( own_cs->own_lock_count>=-1L );

	if ( --own_cs->own_recursion_count == 0 )
		own_cs->own_owning_thread_id = 0;

	if( -1L != InterlockedDecrement( &own_cs->own_lock_count ) &&
		(::GetCurrentThreadId() == own_cs->own_owning_thread_id ) )
	{
		SetEvent( own_cs->own_event );
	}
}

bool TryEnterOwnCriticalSection( own_critical_section* own_cs )
{
	assert( own_cs->own_lock_count>=-1L );

	DWORD current_thread_id = GetCurrentThreadId();
	if ( current_thread_id == own_cs->own_owning_thread_id )
	{ // inside the lock
		InterlockedIncrement( &own_cs->own_lock_count );
		return true;
	}
	else{ 
		if ( -1L == InterlockedCompareExchange( &own_cs->own_lock_count, 0, -1L ) )
			return false;
		own_cs->own_owning_thread_id = current_thread_id;
	}

	++own_cs->own_recursion_count;
	return true;
}

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使用event与无锁算法实现windows平台上的critical section

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