// Copyright: 	Matra-Datavision 1991
// File:	GraphTools_TopologicalSortFromIterator.gxx
// Created:	Wed May 29 17:42:50 1991
// Author:	Denis PASCAL
//		<dp>

#include <Standard_NoMoreObject.hxx>
#include <Standard_NoSuchObject.hxx>
#include <Standard_DomainError.hxx>
#include <TColStd_QueueOfInteger.hxx>
#include <GraphTools_TSNode.hxx>

//=======================================================================
//function : GraphTools_TopologicalSortFromIterator
//purpose  : 
//=======================================================================

GraphTools_TopologicalSortFromIterator::GraphTools_TopologicalSortFromIterator () {}



//=======================================================================
//function : FromVertex
//purpose  : 
//=======================================================================

void GraphTools_TopologicalSortFromIterator::FromVertex (const Vertex& V) 
{
  GraphTools_TSNode newnode;
  myVertices.Add(V,newnode);    
}


//=======================================================================
//function : Perform
//purpose  : 
//=======================================================================

void GraphTools_TopologicalSortFromIterator::Perform 
  (const Graph& G,
   const Standard_Boolean ignoreSelfLoop,
   const Standard_Boolean processCycle)
{
  myIgnoreSelfLoop = ignoreSelfLoop;
  myProcessCycle   = processCycle;
  myCurrent        = 1;
  mySort.Clear();
  // algorithm DS
  Standard_Integer i, indexcurrent, indexadjacent, nbadjacent;
  indexcurrent = 1;
  while (indexcurrent <= myVertices.Extent()) {
    VIterator itV (G,myVertices.FindKey(indexcurrent));
    for ( ; itV.More(); itV.Next()) {
      indexadjacent = myVertices.FindIndex(itV.Value());
      if (indexadjacent == 0) {
        GraphTools_TSNode newnode;
        indexadjacent = myVertices.Add(itV.Value(),newnode);
      }
      if (! (indexcurrent == indexadjacent && myIgnoreSelfLoop)) {
	myVertices(indexcurrent).AddSuccessor(indexadjacent);
	myVertices(indexadjacent).IncreaseRef();
      }
    }
    indexcurrent++;
  }
  // current root vertices queue
  TColStd_QueueOfInteger processQueue;
  Standard_Integer nbVertices = myVertices.Extent();
  for (i = 1 ; i <= nbVertices; i++) {
    if (myVertices(i).NbRef() == 0) processQueue.Push(i);
  }
  // acyclic processing
  while (!processQueue.IsEmpty()) {
    indexcurrent = processQueue.Front();
    mySort.Append(indexcurrent);
    nbadjacent = myVertices(indexcurrent).NbSuccessors();
    for (i = 1; i <= nbadjacent; i++) { 
      indexadjacent = myVertices(indexcurrent).GetSuccessor(i);
      myVertices(indexadjacent).DecreaseRef();
      if (myVertices(indexadjacent).NbRef() == 0) {
	processQueue.Push (indexadjacent);
      }
    }
    processQueue.Pop();
  }
  // cyclic processing
  myCycles = mySort.Length() + 1;
  if (myProcessCycle) {
    for (i = 1 ; i <= nbVertices; i++) {
      if (myVertices(i).NbRef() != 0) mySort.Append(i);
    }
  }
}


//=======================================================================
//function : Reset
//purpose  : 
//=======================================================================

void GraphTools_TopologicalSortFromIterator::Reset ()
{
   myVertices.Clear();
//   myIgnoreSelfLoop : Boolean from Standard;
//   myProcessCycle   : Boolean from Standard;
   mySort.Clear();
//   myCycles         : Integer from Standard;
   myCurrent = 1;
}


//=======================================================================
//function : More
//purpose  : 
//=======================================================================

Standard_Boolean GraphTools_TopologicalSortFromIterator::More () const 
{
  return myCurrent <= mySort.Length();
}


//=======================================================================
//function : Next
//purpose  : 
//=======================================================================

void GraphTools_TopologicalSortFromIterator::Next () 
{
  if (!More()) Standard_NoMoreObject::Raise();
  myCurrent ++;
}


//=======================================================================
//function : Value
//purpose  : 
//=======================================================================

const Vertex& GraphTools_TopologicalSortFromIterator::Value () const {
  if (!More()) Standard_NoSuchObject::Raise();
  return myVertices.FindKey (mySort(myCurrent));
}


//=======================================================================
//function : IsInCycle
//purpose  : 
//=======================================================================

Standard_Boolean GraphTools_TopologicalSortFromIterator::IsInCycle () const 
{
  if (!More()) Standard_NoSuchObject::Raise();
  return myCurrent >= myCycles;
}