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Sourcecode: qt4-x11 version File versions

SegmentMergeQueue.cpp

/*------------------------------------------------------------------------------
* Copyright (C) 2003-2006 Ben van Klinken and the CLucene Team
* 
* Distributable under the terms of either the Apache License (Version 2.0) or 
* the GNU Lesser General Public License, as specified in the COPYING file.
------------------------------------------------------------------------------*/
#include "CLucene/StdHeader.h"
#include "SegmentMergeQueue.h"

#include "SegmentMergeInfo.h"
CL_NS_DEF(index)


      SegmentMergeQueue::SegmentMergeQueue(const int32_t size) {
      //Func - Constructor
      //       Creates a queue of length size
      //Pre  - size >= 0
      //Post - The queue has been created of length size

            //BVK: bug. changed condition from size > 0 to size >= 0
            //if size is 0, as it is  when retrieving a TermEnum 
            //from an empty index this should this should not fail.
        CND_PRECONDITION(size >= 0, "size is too small");

            //Call the initialize method of its superclass. The boolean value  passed here
            //indicates that the superclass PriorityQueue takes the responsibility to have its elements deleted
            //The destructor of SegmentMergInfo will make sure that each intstance it will be closed properly 
            //before it is deleted
            initialize(size,true);
      }

      SegmentMergeQueue::~SegmentMergeQueue(){
      //Func - Destructor
      //       Does nothing as its parent class will clean up everything
      //Pre  - true
      //Post - true
        close();
      }

      void SegmentMergeQueue::close() {
      //Func - Closes and destroyes all SegmentMergeInfo Instances in the queue
    //Pre  - true
      //post - All SegmentMergeInfo Instances in the queue have been closed and  deleted 
      //       The queue is now empty but can still be used

            //call the clear method of the parent class PriorityQueue
        clear();
      }

      bool SegmentMergeQueue::lessThan(SegmentMergeInfo* stiA, SegmentMergeInfo* stiB) {
   //Func - Overloaded method that implements the lessThan operator for the parent class
   //       This method is used by the parent class Priority queue to reorder its internal
   //       data structures. This implementation check if stiA is less than the current term of stiB.
   //Pre  - stiA != NULL
   //       stiB != NULL
   //Post - true is returned if stiA < stiB otherwise false

        CND_PRECONDITION(stiA != NULL, "stiA is NULL");
        CND_PRECONDITION(stiB != NULL, "stiB is NULL");

            //Compare the two terms 
            int32_t comparison = stiA->term->compareTo(stiB->term);
            //Check if they match
            if (comparison == 0){ //todo: can we do an optimized compare here? compare using equals, then compare properly?
                  //If the match check if the base of stiA is smaller than the base of stiB
                  //Note that different bases means that the terms of stiA an stiB ly in different segments
                  return stiA->base < stiB->base; 
            }else{
                  //Terms didn't match so return the difference in positions
                  return comparison < 0;
            }
      }

CL_NS_END

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