-- File:	GraphTools_SortedStrgCmptsFromIterator.cdl
-- Created:	Wed Oct 23 12:07:20 1991
-- Author:	Denis PASCAL
--		<dp@topsn2>
---Copyright:	 Matra Datavision 1991, 1992


generic class SortedStrgCmptsFromIterator from GraphTools
             (Graph     as any;
    	      Vertex    as any;
	      VHasher   as any;
	      VIterator as any)

    ---Purposes: This generic  class  implements the Strong Components
    --           Research  algorithm  from a  set   of  vertices.   An
    --           iterator on  adjacent vertices  of  a given one,  are
    --           requested.   Each   Strong Component     encapsulates
    --           vertices which are part of a cycle, in the underlying
    --           graph.  The interface of this algorithm is made as an
    --           iterator.  A each step it  is possible  to  know  the
    --           number of vertices, which are members  of the current
    --           Strong Components,  and  to  visit each  one.  Strong
    --           Components are visited in such an order than noone is
    --           returned before an other which point to it.


uses StackOfInteger from TColStd,
     ListOfSequenceOfInteger from GraphTools,
     ListIteratorOfListOfSequenceOfInteger from GraphTools     
     
raises NoMoreObject from Standard,
       NoSuchObject from Standard,
       DomainError from Standard


    private class SCMap instantiates IndexedDataMap from TCollection 
                                    (Vertex,Integer,VHasher); 

is

    Create	
    	---Purpose: Create an empty algorithm.
    returns SortedStrgCmptsFromIterator from GraphTools;

    FromVertex (me : in out; V : Vertex)    	
    	---Purpose: Add  <V>  as  initial  condition.  This method  is
	--          cumulative.  Use Perform method before visting the
	--          result of the algorithm.  
	---Level: Public
    raises DomainError from Standard;
    
    Reset (me : in out);
    	---Purpose: Reset the algorithm.  It   may be reused  with new
    	--          conditions.  
    	---Level: Public

    Perform (me : in out; G : Graph);       
    	---Purpose: Peform the  algorithm  in  <G> from initial  setted
       	--          conditions.  
       	---Level: Public
    
    More(me) 
    returns Boolean from Standard;
        ---Purpose: returns  True   if  there are   others  strong
        --          components.
       ---Level: Public

    Next(me : in out) 
        ---Purpose: Set the iterator to the next strong component.
       ---Level: Public
    raises NoMoreObject from Standard;
    
    NbVertices (me) 
    returns Integer from Standard
	---Purpose: Returns number  of vertices of  the current Strong
	--          Components.
        ---Level: Public
    raises NoSuchObject from Standard;

    Value(me; index : Integer from Standard) 
    returns any Vertex
	---Purpose: returns  the vertex of  index <I> of  the  current
	--          Strong Component.
        ---Level: Public
	---C++: return const &          
    raises NoSuchObject from Standard;
	
    Visit (me : in out; k : Integer from Standard;
                        G : Graph) 
       ---Level: Internal
    returns Integer from Standard;
    
fields

-- conditions
    myVertices : SCMap from GraphTools;
-- algorithm    
    myNowIndex : Integer from Standard;
    myStack    : StackOfInteger from TColStd;
-- result    
    mySort     : ListOfSequenceOfInteger from GraphTools;
    myIterator : ListIteratorOfListOfSequenceOfInteger from GraphTools;
    
end SortedStrgCmptsFromIterator;