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CAGuard.cpp
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CAGuard.cpp
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/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Sam Lantinga
slouken@libsdl.org
*/
/*
Note: This file hasn't been modified so technically we have to keep the disclaimer :-(
Copyright: © Copyright 2002 Apple Computer, Inc. All rights reserved.
Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Computer, Inc.
("Apple") in consideration of your agreement to the following terms, and your
use, installation, modification or redistribution of this Apple software
constitutes acceptance of these terms. If you do not agree with these terms,
please do not use, install, modify or redistribute this Apple software.
In consideration of your agreement to abide by the following terms, and subject
to these terms, Apple grants you a personal, non-exclusive license, under AppleÕs
copyrights in this original Apple software (the "Apple Software"), to use,
reproduce, modify and redistribute the Apple Software, with or without
modifications, in source and/or binary forms; provided that if you redistribute
the Apple Software in its entirety and without modifications, you must retain
this notice and the following text and disclaimers in all such redistributions of
the Apple Software. Neither the name, trademarks, service marks or logos of
Apple Computer, Inc. may be used to endorse or promote products derived from the
Apple Software without specific prior written permission from Apple. Except as
expressly stated in this notice, no other rights or licenses, express or implied,
are granted by Apple herein, including but not limited to any patent rights that
may be infringed by your derivative works or by other works in which the Apple
Software may be incorporated.
The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO
WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
COMBINATION WITH YOUR PRODUCTS.
IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION
OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT
(INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*=============================================================================
CAGuard.cp
=============================================================================*/
//=============================================================================
// Includes
//=============================================================================
#include <stdio.h>
#define NDEBUG 1
#include <assert.h>
#include "CAGuard.h"
//#warning Need a try-based Locker too
//=============================================================================
// CAGuard
//=============================================================================
CAGuard::CAGuard()
{
OSStatus theError = pthread_mutex_init(&mMutex, NULL);
assert(theError == 0);
theError = pthread_cond_init(&mCondVar, NULL);
assert(theError == 0);
mOwner = 0;
}
CAGuard::~CAGuard()
{
pthread_mutex_destroy(&mMutex);
pthread_cond_destroy(&mCondVar);
}
bool CAGuard::Lock()
{
bool theAnswer = false;
if(pthread_self() != mOwner)
{
OSStatus theError = pthread_mutex_lock(&mMutex);
assert(theError == 0);
mOwner = pthread_self();
theAnswer = true;
}
return theAnswer;
}
void CAGuard::Unlock()
{
assert(pthread_self() == mOwner);
mOwner = 0;
OSStatus theError = pthread_mutex_unlock(&mMutex);
assert(theError == 0);
}
bool CAGuard::Try (bool& outWasLocked)
{
bool theAnswer = false;
outWasLocked = false;
if (pthread_self() == mOwner) {
theAnswer = true;
outWasLocked = false;
} else {
OSStatus theError = pthread_mutex_trylock(&mMutex);
if (theError == 0) {
mOwner = pthread_self();
theAnswer = true;
outWasLocked = true;
}
}
return theAnswer;
}
void CAGuard::Wait()
{
assert(pthread_self() == mOwner);
mOwner = 0;
OSStatus theError = pthread_cond_wait(&mCondVar, &mMutex);
assert(theError == 0);
mOwner = pthread_self();
}
void CAGuard::Notify()
{
OSStatus theError = pthread_cond_signal(&mCondVar);
assert(theError == 0);
}