vmqueue.cpp

TOOL (Tiny Object Oriented Language) is an easily-embedded, object-oriented, C++-like-language inter

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/*                              SOURCE FILE                                  */
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/*
       $Archive:   $

      $Revision:   $
          $Date:   $
        $Author:   $

    Description:   Implemenation for the queue class for VMVariant classes

                      TOOL And XML FORMS License
                      ==========================

                      Except where otherwise noted, all of the documentation 
                      and software included in the TOOL package is 
                      copyrighted by Michael Swartzendruber.

                      Copyright (C) 2005 Michael John Swartzendruber. 
                      All rights reserved.

                      Access to this code, whether intentional or accidental,
                      does NOT IMPLY any transfer of rights.

                      This software is provided "as-is," without any express 
                      or implied warranty. In no event shall the author be held
                      liable for any damages arising from the use of this software.

                      Permission is granted to anyone to use this software for 
                      any purpose, including commercial applications, and to 
                      alter and redistribute it, provided that the following 
                      conditions are met:

                      1. All redistributions of source code files must retain 
                         all copyright notices that are currently in place, 
                         and this list of conditions without modification.

                      2. The origin of this software must not be misrepresented;
                         you must not claim that you wrote the original software.

                      3. If you use this software in another product, an acknowledgment
                         in the product documentation would be appreciated but is
                         not required.

                      4. Modified versions in source or binary form must be plainly 
                         marked as such, and must not be misrepresented as being 
                         the original software.
*/
static char OBJECT_ID[] = "$Revision:   $ : $Date:   $";
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#include "../../../stdafx.h"
#include "../VMException.h"
#include "../VMCoreGlobal.h"
#include "VMQueue.h"



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/*
     FUNCTION NAME:  DeepCopy

       DESCRIPTION:  performs an elemental copy of another stack

             INPUT:  roOther - the stack to copy
            OUTPUT:  none

           RETURNS:  none
*/
void VMDataQueue::DeepCopy( VMDataQueue& roOther )
{
  if ( roOther.GetCount() == 0 )
  {
    m_pxHead = NULL;
    m_pxTail = NULL;
    m_xCount = 0;
    return;
  }

  m_pxHead = (PNODE)new NODE;
   
  if ( NULL == m_pxHead )
  {
    VMException  oError( __FILE__, 
                         __LINE__, 
                         ALLOCATION_ERROR, 
                         VMException::fatal );
    throw oError;
  }

  m_pxTail = m_pxHead;

  PNODE pxSource = roOther.m_pxHead;

  while ( true )
  {
    m_pxTail->m_oData.CloneValue( pxSource->m_oData );
    ++m_xCount;

    if ( NULL != pxSource->m_pxNext )
    {
       m_pxTail->m_pxNext = (PNODE) new NODE;
         
       if ( NULL == m_pxTail->m_pxNext )
       {
         VMException  oError( __FILE__, 
                              __LINE__, 
                              ALLOCATION_ERROR, 
                              VMException::fatal );
         throw oError;
       }

       m_pxTail = m_pxTail->m_pxNext;
       pxSource = pxSource->m_pxNext;
    }
    else
    {
      m_pxTail->m_pxNext = NULL;
      break;
    }
  }
}
/* End of function "VMDataQueue::DeepCopy"
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/*
     FUNCTION NAME:  Clear

       DESCRIPTION:  Pops all elements off the queue

             INPUT:  void
            OUTPUT:  none

           RETURNS:  none
*/
void VMDataQueue::Clear( void )
{
  VMVariant xIgnored;
  while ( m_xCount )
  {
    Dequeue( xIgnored );
  }
}
/* End of function "VMDataQueue::Clear"
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/*
     FUNCTION NAME:  VMDataQueue

       DESCRIPTION:  ctor.

             INPUT:  void
            OUTPUT:  none

           RETURNS:  none
*/
VMDataQueue::VMDataQueue( void )
{
  m_xCount = 0;
  m_pxHead = NULL;
  m_pxTail = NULL;
}
/* End of function "VMDataQueue::VMDataQueue"
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/*
     FUNCTION NAME:  VMDataQueue

       DESCRIPTION:  Copy ctor

             INPUT:  roOther - the stack to copy
            OUTPUT:  none

           RETURNS:  none
*/
VMDataQueue::VMDataQueue( VMDataQueue& roOther )
{
  m_xCount = 0;
  DeepCopy( roOther );
}
/* End of function "VMDataQueue::VMDataQueue"
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/*
     FUNCTION NAME:  operator =

       DESCRIPTION:  clears this then a deep copy (see above) of another stack

             INPUT:  roOther - the stack to copy
            OUTPUT:  none

           RETURNS:  none
*/
void VMDataQueue::operator =( VMDataQueue& roOther )
{
  Clear();
  DeepCopy( roOther );
}
/* End of function "="
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/*
     FUNCTION NAME:  ~VMDataQueue

       DESCRIPTION:  clears this 

             INPUT:  void
            OUTPUT:  none

           RETURNS:  none
*/
VMDataQueue::~VMDataQueue( void )
{
  Clear();
}
/* End of function "VMDataQueue::~VMDataQueue"
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/*****************************************************************************/
/*
     FUNCTION NAME:  Enqueue

       DESCRIPTION:  does the work required to add a new element to this 
                     by allocating a new node, copying the item into the node
                     data element and then linking the head/next pointers
                     appropriately.

                     NOTE: The item to be pushed MUST IMPLEMENT a copy constructor
             INPUT:  void
            OUTPUT:  none

           RETURNS:  none
*/
void VMDataQueue::Enqueue( VMVariant& roItem )
{
  PNODE pNewNode = new NODE;
 
  if ( NULL == pNewNode )
  {
    VMException  oError( __FILE__, 
                         __LINE__, 
                         ALLOCATION_ERROR, 
                         VMException::fatal );
    throw oError;
  }

  pNewNode->m_pxNext = NULL;
  pNewNode->m_oData.CloneValue( roItem );

  if ( NULL != m_pxTail )
  {
    m_pxTail->m_pxNext = pNewNode;
  }
  else
  {
    m_pxHead = pNewNode;
  }
  
  m_pxTail = pNewNode;

  ++m_xCount;
}
/* End of function "VMDataQueue::Enqueue"
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/*
     FUNCTION NAME:  Dequeue

       DESCRIPTION:  returns the item that is at the top of the stack

             INPUT:  void
            OUTPUT:  none

           RETURNS:  true if an item returned, false if not
*/
bool VMDataQueue::Dequeue( VMVariant& roOutput )
{
  if ( NULL == m_pxHead )
  {
    return( false );
  }

  roOutput.CloneValue( m_pxHead->m_oData );

  PNODE pNewHead = m_pxHead->m_pxNext;

  delete m_pxHead;

  m_pxHead = pNewHead;

  --m_xCount;

  if ( 0 == m_xCount )
  {
    m_pxTail = NULL;
  }

  return( true );
}
/* End of function "VMDataQueue::Dequeue"
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/*
     FUNCTION NAME:  GetCount

       DESCRIPTION:  returns the number of items stored in this 

             INPUT:  void
            OUTPUT:  none

           RETURNS:  the number of items
*/
size_t VMDataQueue::GetCount( void )
{
  return( m_xCount );
}
/* End of function "VMDataQueue::GetCount"
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/* Check-in history */
/*
 *$Log:  $
*/
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