UHashTable(3U)						    InterViews Reference Manual 					    UHashTable(3U)

NAME

       UHashTable, UHashElem - hash table classes

SYNOPSIS

       #include <Unidraw/uhash.h>

DESCRIPTION

       UHashTable  implements  a  simple  open	hash  table.   The  number of slots can be specified when the table is created.  UHashTable stores
       UHashElem instances, which contain the key that is hashed.  Code that uses UHashTables may derive from UHashElem to store data in  addition
       to the key.  UHashTable also provides operations for iterating over the elements in the hash table.

UHASHELEM OPERATIONS

       UHashElem(void* = nil)
	      Create a UHashElem with the given key value.

       void* GetKey()
       void SetKey(void*)
	      Explicitly get and set the element's key value.

UHASHTABLE PUBLIC OPERATIONS

       UHashTable(int nslots)
	      Create a new UHashTable, specifying its number of slots.

       virtual void Register(void* key, UHashElem* = nil)
	      Make  an	entry  into  the hash table.  If no UHashElem is supplied, this function call the CreateElem function (described below) to
	      create one, and it will call SetKey (with key as its argument) on the result.

       virtual void Unregister(void* key)
	      Remove the element with the matching key from the hash table and delete it.

       void First(Iterator&)
       void Next(Iterator&)
       boolean Done(Iterator)
       UHashElem* GetElem(Iterator)
	      Operations for iterating over the elements in the hash table.  These operation do not guarantee a particular ordering for the itera-
	      tion.   First  initializes  an iterator to point to the first element in the traversal, Next increments the iterator to point to the
	      following element, and Done returns whether or not the iterator points beyond the last element in the  traversal.   GetElem  returns
	      the element to which the given iterator points.

       UHashElem* Find(void* key)
	      Find the element with the matching key (as defined by the Equal operation, described below) in the hash table.

UHASHTABLE PROTECTED OPERATIONS

       virtual UHashElem* CreateElem()
	      Return a new UHashElem instance.	Subclasses of UHashTable should redefine this function if they use subclasses of UHashElem.

       virtual int Hash(void* key)
	      Hash the specified key to return a slot index.  This value should be less than the value of the _nslots member variable.

       virtual boolean Equal(void* key1, void* key2)
	      Return  whether  the  specified  keys  are equivalent.  By default, Equal simply compares the pointers for equality.  Subclasses may
	      redefine this operation to make more sophisticated comparisons.

SEE ALSO

       Iterator(3U)

Unidraw 							  3 October 1990						    UHashTable(3U)