wire.cpp

/***************************************************************************
 *   Copyright (C) 2005 by David Saxton                                    *
 *   david@bluehaze.org                                                    *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 ***************************************************************************/

#include "pin.h"
#include "wire.h"
#include <cassert>
#include <kdebug.h>
#include <cmath>

using namespace std;

Wire::Wire( Pin *startPin, Pin *endPin )
{
        assert(startPin);
        assert(endPin);

        m_pStartPin = startPin;
        m_pEndPin = endPin;
        m_current = 0.;
        m_bCurrentIsKnown = false;

        m_pStartPin->addOutputWire(this);
        m_pEndPin->addInputWire(this);
}

Wire::~Wire()
{
}

bool Wire::calculateCurrent()
{
        if ( m_pStartPin->currentIsKnown() && m_pStartPin->numWires() < 2 ) {
                m_current = m_pStartPin->current();
                m_bCurrentIsKnown = true;
                return true;
        }

        if ( m_pEndPin->currentIsKnown() && m_pEndPin->numWires() < 2 ) {
                m_current = -m_pEndPin->current();
                m_bCurrentIsKnown = true;
                return true;
        }

        if ( m_pStartPin->currentIsKnown() ) {
                double i = m_pStartPin->current();
                bool ok = true;
                const WireList outlist = m_pStartPin->outputWireList();
                WireList::const_iterator end = outlist.end();
                for(WireList::const_iterator it = outlist.begin(); it != end && ok; ++it)
                {
                        if ( *it && (Wire*)*it != this ) {
                                if ( (*it)->currentIsKnown() )
                                        i -= (*it)->current();
                                else ok = false;
                        }
                }

                const WireList inlist = m_pStartPin->inputWireList();
                end = inlist.end();
                for(WireList::const_iterator it = inlist.begin(); it != end && ok; ++it) {
                        if ( *it && (Wire*)*it != this ) {
                                if ( (*it)->currentIsKnown() )
                                        i += (*it)->current();
                                else ok = false;
                        }
                }
                
                if(ok) {
                        m_current = i;
                        m_bCurrentIsKnown = true;
                        return true;
                }
        }

        if ( m_pEndPin->currentIsKnown() ) {
                double i = -m_pEndPin->current();
                bool ok = true;
                const WireList outlist = m_pEndPin->outputWireList();
                WireList::const_iterator end = outlist.end();
                for ( WireList::const_iterator it = outlist.begin(); it != end && ok; ++it ) {
                        if ( *it && (Wire*)*it != this ) {
                                if ( (*it)->currentIsKnown() )
                                        i += (*it)->current();
                                else ok = false;
                        }       
                }

                const WireList inlist = m_pEndPin->inputWireList();
                end = inlist.end();

                for ( WireList::const_iterator it = inlist.begin(); it != end && ok; ++it ) {
                        if ( *it && (Wire*)*it != this ) {
                                if ( (*it)->currentIsKnown() )
                                        i -= (*it)->current();
                                else ok = false;
                        }
                }

                if (ok) {
                        m_current = i;
                        m_bCurrentIsKnown = true;
                        return true;
                }
        }

        m_bCurrentIsKnown = false;
        return false;
}

double Wire::voltage() const
{
        // wires conduct, right?
        double error = fabs(m_pStartPin->voltage() - m_pEndPin->voltage());
        if(error > 1e-9) kdError() << "Wire not conducting right, voltage off by " << error << endl;
        return m_pStartPin->voltage();
}

void Wire::setCurrentKnown( bool known )
{
        m_bCurrentIsKnown = known;
        if (!known) m_current = 0.;
}

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