/*

 *

 *  Copyright (C) 1994-2021, OFFIS e.V.

 *  All rights reserved.  See COPYRIGHT file for details.

 *

 *  This software and supporting documentation were developed by

 *

 *    OFFIS e.V.

 *    R&D Division Health

 *    Escherweg 2

 *    D-26121 Oldenburg, Germany

 *

 *

 *  Module:  dcmdata

 *

 *  Author:  Gerd Ehlers

 *

 *  Purpose: stack class

 *

 */

#include "dcmtk/config/osconfig.h"    /* make sure OS specific configuration is included first */

#include "dcmtk/ofstd/ofcast.h"

#include "dcmtk/ofstd/ofstream.h"

#include "dcmtk/dcmdata/dcstack.h"

// ************************************************

// *** DcmStackNode() *****************************

// ************************************************

DcmStackNode::DcmStackNode( DcmObject *obj )

  : link(NULL),

    objNodeValue(obj)

{

}

// ********************************

DcmStackNode::~DcmStackNode()

{

}

// ********************************

DcmObject* DcmStackNode::value() const

{

    return objNodeValue;

}

// ************************************************

// *** DcmStack() *********************************

// ************************************************

DcmStack::DcmStack()

  : topNode_(NULL),

    cardinality_(0)

{

}

// ************************************************

DcmStack::DcmStack( const DcmStack & oldStack)

  : topNode_(NULL),

    cardinality_(oldStack.cardinality_)

{

    if (cardinality_)

    {

        topNode_ = new DcmStackNode(oldStack.topNode_->objNodeValue);

        DcmStackNode * oldPtr = oldStack.topNode_->link;

        DcmStackNode * newPtr = topNode_;

        while (oldPtr)

        {

            newPtr->link = new DcmStackNode(oldPtr->objNodeValue);

            oldPtr = oldPtr->link;

            newPtr = newPtr->link;

        }

    }

}

// ********************************

DcmStack::~DcmStack()

{

    clear();

}

// ********************************

void DcmStack::clear()

{

    DcmStackNode *node;

    while (topNode_ != NULL)

    {

        node = topNode_;

        topNode_ = topNode_->link;

        delete node;

    }

    cardinality_ = 0;

}

// ********************************

DcmObject* DcmStack::push( DcmObject *obj )

{

    if ( obj != NULL )

    {

        DcmStackNode *node = new DcmStackNode( obj );

        node->link = topNode_;

        topNode_ = node;

        cardinality_++;

    }

    return obj;

}

// ********************************

DcmObject* DcmStack::pop()

{

    DcmObject *obj;

    DcmStackNode *node;

    if ( topNode_ != NULL )

    {

        obj = topNode_->value();

        node = topNode_;

        topNode_ = topNode_->link;

        delete node;

        cardinality_--;

    }

    else

        obj = NULL;

    return obj;

}

// ********************************

DcmObject* DcmStack::elem(const unsigned long number) const

{

    unsigned long num = number;

    DcmObject *obj;

    DcmStackNode *node = topNode_;

    while ( num > 0 && node != NULL )

    {

         node = node->link;

         --num;

    }

    if ( node != NULL )

        obj = node->value();

    else

        obj = NULL;

    return obj;

}

// ********************************

DcmObject* DcmStack::top() const

{

    DcmObject *obj;

    if ( topNode_ != NULL )

        obj = topNode_->value();

    else

        obj = NULL;

    return obj;

}

// ********************************

unsigned long DcmStack::card() const

{

    return cardinality_;

}

// ********************************

OFBool DcmStack::empty() const

{

    return OFstatic_cast(OFBool, topNode_ == NULL );

}

DcmStack& DcmStack::operator=(const DcmStack& arg)

{

  if (this != &arg)

  {

    clear();

    cardinality_ = arg.cardinality_;

    if (cardinality_)

    {

        topNode_ = new DcmStackNode(arg.topNode_->objNodeValue);

        DcmStackNode * oldPtr = arg.topNode_->link;

        DcmStackNode * newPtr = topNode_;

        while (oldPtr)

        {

            newPtr->link = new DcmStackNode(oldPtr->objNodeValue);

            oldPtr = oldPtr->link;

            newPtr = newPtr->link;

        }

    }

  }

  return *this;

}

OFBool DcmStack::operator<(const DcmStack& arg) const

{

  if (cardinality_ < arg.cardinality_) return OFTrue;

  if (cardinality_ > arg.cardinality_) return OFFalse;

  // cardinality_ is equal. Now walk through stack and do pointer arithmetics

  DcmStackNode * thisPtr = topNode_;

  DcmStackNode * argPtr = arg.topNode_;

  while (thisPtr)

  {

      if (thisPtr->objNodeValue < argPtr->objNodeValue) return OFTrue;

      if (thisPtr->objNodeValue > argPtr->objNodeValue) return OFFalse;

      thisPtr = thisPtr->link;

      argPtr = argPtr->link;

  }

  return OFFalse; // stacks are equal

}

OFBool DcmStack::operator==(const DcmStack& arg) const

{

  if (cardinality_ != arg.cardinality_) return OFFalse;

  DcmStackNode * thisPtr = topNode_;

  DcmStackNode * argPtr = arg.topNode_;

  while (thisPtr)

  {

      if (thisPtr->objNodeValue != argPtr->objNodeValue) return OFFalse;

      thisPtr = thisPtr->link;

      argPtr = argPtr->link;

  }

  return OFTrue;

}