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// File: NCollection_UBTreeFiller.hxx
// Created: 18.10.02 10:34:57
// Author: Michael SAZONOV
// Copyright: Open CASCADE 2002
#ifndef NCollection_UBTreeFiller_HeaderFile
#define NCollection_UBTreeFiller_HeaderFile
#include <NCollection_UBTree.hxx>
#include <NCollection_Vector.hxx>
#include <stdlib.h>
#include <stdio.h>
/**
* This class is used to fill an UBTree in a random order.
* The quality of a tree is much better (from the point of view of
* the search time) if objects are added to it in a random order to
* avoid adding a chain of neerby objects one following each other.
*
* This class collects objects to be added, and then add them to the tree
* in a random order.
*/
template <class TheObjType, class TheBndType> class NCollection_UBTreeFiller
{
public:
// ---------- PUBLIC TYPES ----------
//! Structure of pair (object, bnd box)
struct ObjBnd
{
TheObjType myObj;
TheBndType myBnd;
ObjBnd (const TheObjType& theObj, const TheBndType& theBnd)
: myObj(theObj), myBnd(theBnd) {}
ObjBnd ()
: myObj(TheObjType()), myBnd(TheBndType()) {}
};
//! UBTree algorithm
typedef NCollection_UBTree<TheObjType, TheBndType> UBTree;
typedef TYPENAME UBTree::TreeNode UBTreeNode;
// ---------- PUBLIC METHODS ----------
/**
* Constructor.
* @param theTree
* Tree instance that is to be filled.
* @param isFullRandom
* Takes effect when the number of items is large (order of 50,000). When
* it is True, the code uses the maximal randomization allowing a better
* balanced tree. If False, the randomization/tree balance are worse but
* the tree filling is faster due to better utilisation of CPU L1/L2 cache.
*/
NCollection_UBTreeFiller (UBTree& theTree,
const Standard_Boolean isFullRandom = Standard_True)
: myTree(theTree), mySeed(1), myIsFullRandom (isFullRandom)
{
#ifndef _REENTRANT
// We use srand/rand for a single threaded application
// and rand_r for a multi threaded one.
// _REENTRANT must be defined for a multi threaded application.
srand (mySeed);
#endif
}
//! Adds a pair (theObj, theBnd) to my sequence
void Add (const TheObjType& theObj, const TheBndType& theBnd)
{ mySeqPtr.Append (ObjBnd (theObj, theBnd)); }
/**
* Fills the tree with the objects from my sequence. This method clears
* the internal buffer of added items making sure that no item would be added
* twice.
* @return
* the number of objects added to the tree.
*/
Standard_EXPORT Standard_Integer Fill ();
/**
* Check the filled tree for the total number of items and the balance
* outputting these results to ostream.
* @return
* the tree size (the same value is returned by method Fill()).
*/
Standard_EXPORT Standard_Integer CheckTree (Standard_OStream& theStream);
/**
* Destructor. Fills the tree with accumulated items if they have not been
* passed by a previous call of method Fill().
*/
~NCollection_UBTreeFiller ()
{
if (mySeqPtr.Length() > 0)
#ifdef DEB_UBTREE
cout << "~NCollection_UBTreeFiller: " << Fill()
<< " objects added to the tree" << endl;
#else
Fill();
#endif
}
private:
// Assignment operator is made empty and private in order to
// avoid warning on MSVC (C4512)
void operator = (const NCollection_UBTreeFiller&) {}
static Standard_Real checkNode (const UBTreeNode& theNode,
const Standard_Integer theLength,
Standard_Integer& theNumber);
private:
// ---------- PRIVATE FIELDS ----------
UBTree& myTree;
NCollection_Vector<ObjBnd> mySeqPtr;
int mySeed; //!< seed for rand
Standard_Boolean myIsFullRandom;
};
#ifdef _REENTRANT
inline int take_random (int * theSeed)
{
return rand_r ((unsigned *) theSeed);
}
#else
inline int take_random (int *)
{
return rand();
}
#endif
//=======================================================================
//function : Fill
//purpose :
//=======================================================================
template <class TheObjType, class TheBndType>
Standard_Integer NCollection_UBTreeFiller<TheObjType,TheBndType>::Fill ()
{
Standard_Integer i, nbAdd = mySeqPtr.Length();
// Fisher-Yates randomization
if (myIsFullRandom)
for (i = nbAdd; i > 0; i--) {
unsigned int ind = take_random(&mySeed);
if (i > RAND_MAX) {
const unsigned int ind1 = take_random(&mySeed);
ind += (ind1 << 15);
}
ind = ind % i;
const ObjBnd& aObjBnd = mySeqPtr(ind);
myTree.Add (aObjBnd.myObj, aObjBnd.myBnd);
mySeqPtr(ind) = mySeqPtr(i-1);
}
else
for (i = nbAdd; i > 0; i--) {
unsigned int ind = take_random(&mySeed);
ind = i - (ind % i) - 1;
const ObjBnd& aObjBnd = mySeqPtr(ind);
myTree.Add (aObjBnd.myObj, aObjBnd.myBnd);
mySeqPtr(ind) = mySeqPtr(i-1);
}
mySeqPtr.Clear();
return nbAdd;
}
//=======================================================================
//function : CheckTree
//purpose :
//=======================================================================
template <class TheObjType, class TheBndType>
Standard_Integer NCollection_UBTreeFiller<TheObjType,TheBndType>::CheckTree
(Standard_OStream& theStream)
{
Standard_Integer aNumber(0);
const Standard_Real aLen = checkNode (myTree.Root(), 0, aNumber);
const Standard_Real num = (double) aNumber;
const Standard_Real aLen1 = sqrt (aLen / num);
const Standard_Real aLen0 = log(num) / log(2.);
char buf[128];
sprintf (buf, "Checking UBTree:%8d leaves, balance =%7.2f",
aNumber, aLen1 / aLen0);
theStream << buf << endl;
return aNumber;
}
//=======================================================================
//function : checkNode
//purpose :
//=======================================================================
template <class TheObjType, class TheBndType>
Standard_Real NCollection_UBTreeFiller<TheObjType,TheBndType>::checkNode
(const TYPENAME NCollection_UBTree<TheObjType, TheBndType>::TreeNode& theNode,
const Standard_Integer theLength,
Standard_Integer& theNumber)
{
Standard_Real aLength;
if (!theNode.IsLeaf())
aLength = (checkNode (theNode.Child(0), theLength+1, theNumber) +
checkNode (theNode.Child(1), theLength+1, theNumber));
else {
theNumber++;
aLength = theLength * theLength;
}
return aLength;
}
#endif
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