UMap - maintains a mapping between two sets of pointers

SYNOPSIS

       #include <Unidraw/umap.h>

DESCRIPTION

       UMap  is an abstract class for objects that store an arbi-
       trary number of pointer  pairs  and  can  search  to  find
       either  member  of  a  pair  given  the other.  A UMapElem
       object stores each pointer pair in the UMap.  UMapElem  is
       an  abstract  class  that  defines  virtuals for returning
       either member of the pair, referred to as the id  and  the
       tag.   Subclasses  of  UMapElem redefine these virtuals to
       return either member of the pair they store.

UMAPELEM PUBLIC OPERATIONS

       UMapElem()
              The base class constructor does nothing by default.

       virtual void* id()
       virtual void* tag()
              Return  the id or the tag that the UMapElem stores.
              Subclasses typically define  two  member  variables
              that  store pair's values and redefine these opera-
              tions to return them.

UMAP PUBLIC OPERATIONS

       virtual ~UMap()
              The destructor deletes all UMapElem objects in  the
              UMap.

       int Count()
              Return  the  number of mappings in the UMap, corre-
              sponding to the number of UMapElems that have  been
              registered.

       void Clear()
              Delete  all the UMapElem mappings in the UMap with-
              out destroying the UMap.

UMAP PROTECTED OPERATIONS

       UMap() The base class constructor does nothing by default.

       void Register(UMapElem*)
       void Unregister(UMapElem*)
              Register or remove a UMapElem from the UMap.

       int Index(UMapElem*)
       UMapElem* Elem(int index)
              A  UMap  stores  its  UMapElem in its _elems UArray
              protected member variable.   The  Index  operations
              returns the index of the given UMapElem in the UAr-
              sponding operations on the UArray.

       virtual UMapElem* FindId(void* id)
       virtual UMapElem* FindTag(void* tag)
              FindId searches the UMap for the  UMapElem  element
              containing the given id, while FindTag searches for
              the one with the given tag.  These operations  per-
              form  linear  searches  by default, comparing their
              arguments against the values that the UMapElems' id
              and tag operations return.  The comparison is based
              on the  pointer  values;  subclasses  can  redefine
              these operations to make more sophisticated compar-
              isons based on the id or  tags  actual  type.   For
              example,  if either the id is a string, then FindId
              might do a string comparison to detect a match.

SEE ALSO

       UArray(3U)