/**************************************************************************\
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 *  Copyright (C) 1998-2007 by Systems in Motion.  All rights reserved.
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 *  See the file LICENSE.GPL at the root directory of this source
 *  distribution for additional information about the GNU GPL.
 *
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 *  GPL, and for taking advantage of the additional benefits of our
 *  support services, please contact Systems in Motion about acquiring
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 *
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\**************************************************************************/

/*!
  \class SoCounter SoCounter.h Inventor/engines/SoCounter.h
  \brief The SoCounter class is an integer counter engine.
  \ingroup engines

  The engine counts from its \a min value to its \a max value, adding
  the value of \a step each time \a trigger is touched.

  SoCounter provides a convenient way of keeping track of the number
  of times some event in your application is triggered.
*/

/*!
  \var SoSFShort SoCounter::min
  Minimum value for counter.
*/

/*!
  \var SoSFShort SoCounter::max
  Maximum value for counter.
*/

/*!
  \var SoSFShort SoCounter::step
  Counter step value.
*/

/*!
  \var SoSFTrigger SoCounter::trigger
  Increment counter (using step).
*/

/*!
  \var SoSFShort SoCounter::reset
  Reset counter to this value. The value will be clamped between min
  and max, and step will be accounted for.
*/

/*!
  \var SoEngineOutput SoCounter::output
  (SoSFShort) Output which contains the current counter value.
*/


/*!
  \var SoEngineOutput SoCounter::syncOut
  (SoSFTrigger) Triggers every time counter restarts at SoCounter::min.
*/

#include <Inventor/engines/SoCounter.h>
#include <Inventor/lists/SoEngineOutputList.h>
#include <Inventor/engines/SoSubEngineP.h>

SO_ENGINE_SOURCE(SoCounter);

/*!
  Default constructor.
*/
SoCounter::SoCounter(void)
{
  SO_ENGINE_INTERNAL_CONSTRUCTOR(SoCounter);

  SO_ENGINE_ADD_INPUT(min, (0));
  SO_ENGINE_ADD_INPUT(max, (1));
  SO_ENGINE_ADD_INPUT(step, (1));
  SO_ENGINE_ADD_INPUT(trigger, ());
  SO_ENGINE_ADD_INPUT(reset, (0));

  SO_ENGINE_ADD_OUTPUT(output, SoSFShort);
  SO_ENGINE_ADD_OUTPUT(syncOut, SoSFTrigger);

  this->syncOut.enable(FALSE);  // Disable notification

  this->value = 0;
  this->numsteps = 0;
}

/*!
  Destructor.

  Protected, as engines are not supposed to be explicitly deleted, but
  rather take care of their own destiny by monitoring their reference
  count.
*/
SoCounter::~SoCounter()
{
}

// Documented in superclass.
void
SoCounter::initClass()
{
  SO_ENGINE_INTERNAL_INIT_CLASS(SoCounter);
}

// doc in parent
void
SoCounter::evaluate()
{
  SO_ENGINE_OUTPUT(output,SoSFShort,setValue(this->value));
}

// doc in parent
void
SoCounter::inputChanged(SoField *which)
{
  // Default to not notifying fields connected to the syncOut output.
  this->syncOut.enable(FALSE);

  if (which == &this->trigger) {
    this->numsteps += 1;
    this->value += this->step.getValue();
    if (this->value > this->max.getValue()) {
      this->value = this->min.getValue();
      this->numsteps = 0;
      this->syncOut.enable(TRUE);
    }
    else if (this->value < this->min.getValue()) {
      this->value = this->max.getValue();
      this->numsteps = 0;
      this->syncOut.enable(TRUE);
    }
  }
  else if (which == &this->reset) {
    short minval = this->min.getValue();
    short maxval = this->max.getValue();
    short resetval = this->reset.getValue();
    if (resetval < minval) {
      this->numsteps = 0;
      this->value = minval;
    }
    else {
      if (resetval > maxval) resetval = maxval;
      short stepval = this->step.getValue();
      this->numsteps = (resetval - minval) / stepval;
      this->value = minval + this->numsteps * stepval;
    }
  }
  else if (which == &this->max) {
    if (this->max.getValue() < this->min.getValue()) {
      this->min.setValue(this->max.getValue());
      this->value = this->max.getValue();
      this->numsteps = 0;
    }
    if (this->max.getValue() < this->value) {
      this->value = this->min.getValue();
      this->numsteps = 0;
    }
  }
  else if (which == &this->min) {
    if (this->max.getValue() < this->min.getValue()) {
      this->max.setValue(this->min.getValue());
      this->numsteps = 0;
    }
    this->value = this->min.getValue() + this->step.getValue() * this->numsteps;
    if (this->value > this->max.getValue()) {
      this->numsteps = 0;
      this->value = this->min.getValue();
    }
  }
  else if (which == &this->step) {
    this->value = this->min.getValue() + this->step.getValue() * this->numsteps;
    if (this->value > this->max.getValue()) {
      this->numsteps = 0;
      this->value = this->min.getValue();
    }
  }
}