ofxsMultiThread.cpp

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/*
 * OFX Support Library, a library that skins the OFX plug-in API with C++ classes.
 * Copyright (C) 2004-2005 The Open Effects Association Ltd
 * Author Bruno Nicoletti bruno@thefoundry.co.uk
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * Neither the name The Open Effects Association Ltd, nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The Open Effects Association Ltd
 * 1 Wardour St
 * London W1D 6PA
 * England
 *
 *
 */

#include "ofxsSupportPrivate.h"
#include "ofxsUtilities.h"
#include <iostream>

namespace OFX {

namespace MultiThread {

////////////////////////////////////////////////////////////////////////////////
// SMP class

/** @brief ctor */
Processor::Processor( void )
{}

/** @brief dtor */
Processor::~Processor()
{}

/** @brief Function to pass to the multi thread suite */
void Processor::staticMultiThreadFunction( unsigned int threadIndex, unsigned int threadMax, void* customArg )
{
        // cast the custom arg to one of me
        Processor* me = (Processor*)  customArg;

        // and call my thread function
        me->multiThreadFunction( threadIndex, threadMax );
}

/** @brief Function to pass to the multi thread suite */
void Processor::multiThread( const unsigned int nCPUs )
{
        unsigned int realNbCPUs = nCPUs;
        // if 0, use all the CPUs we can
        if( realNbCPUs == 0 )
                realNbCPUs = OFX::MultiThread::getNumCPUs();

        if( realNbCPUs == 0 )
        {
                OFXS_COUT_ERROR( "Run process on 0 cpus... it seems to be a problem." );
        }
        else if( realNbCPUs == 1 ) // if 1 cpu, don't bother with the threading
        {
                multiThreadFunction( 0, 1 );
        }
        else
        {
                // OK do it
                OfxStatus stat = OFX::Private::gThreadSuite->multiThread( staticMultiThreadFunction, realNbCPUs, (void*)this );

                // did we do it?
                throwSuiteStatusException( stat );
        }
}

////////////////////////////////////////////////////////////////////////////////
// futility functions

/** @brief Has the current thread been spawned from an MP */
bool isSpawnedThread( void )
{
        int v = OFX::Private::gThreadSuite->multiThreadIsSpawnedThread();

        return v != 0;
}

/** @brief The number of CPUs that can be used for MP-ing */
unsigned int getNumCPUs( void )
{
        unsigned int n = 1;
        OfxStatus stat = OFX::Private::gThreadSuite->multiThreadNumCPUs( &n );

        if( stat != kOfxStatOK )
                n = 1;
        return n;
}

/** @brief The index of the current thread. From 0 to numCPUs() - 1 */
unsigned int getThreadIndex( void )
{
        unsigned int n = 0;
        OfxStatus stat = OFX::Private::gThreadSuite->multiThreadIndex( &n );

        if( stat != kOfxStatOK )
                n = 0;
        return n;
}

////////////////////////////////////////////////////////////////////////////////
// MUTEX class

/** @brief ctor */
Mutex::Mutex( int lockCount )
        : _handle( 0 )
{
        OfxStatus stat = OFX::Private::gThreadSuite->mutexCreate( &_handle, lockCount );

        throwSuiteStatusException( stat );
}

/** @brief dtor */
Mutex::~Mutex( void )
{
        /*OfxStatus stat = */OFX::Private::gThreadSuite->mutexDestroy( _handle );
}

/** @brief lock it, blocks until lock is gained */
void Mutex::lock()
{
        OfxStatus stat = OFX::Private::gThreadSuite->mutexLock( _handle );

        throwSuiteStatusException( stat );
}

/** @brief unlock it */
void Mutex::unlock()
{
        OfxStatus stat = OFX::Private::gThreadSuite->mutexUnLock( _handle );

        throwSuiteStatusException( stat );
}

/** @brief attempt to lock, non-blocking */
bool Mutex::tryLock()
{
        OfxStatus stat = OFX::Private::gThreadSuite->mutexTryLock( _handle );

        return stat == kOfxStatOK;
}

};
};