-- filename hashtabl.ads 2:39PM  10/11/95

-- this generic HashTable package takes:
--			the Key and Contents types (as private)
--			the NumberOfBuckets to use
--			a hash function that maps a key to a bucket#
--			and Put procedures for the Key and Contents types
-- and defines a type Table, indexed by type Key and storing items of type
-- Contents.

with  list;
generic

  type Key is private;
  type Contents is private;
  NumberOfBuckets: Positive;
  with function Hash(S:Key) return Positive;
  with procedure putkey(S:key);
  with procedure putcontents(V:Contents);

package HashTable is

  type Table is private;

  procedure put(T:in Table);

  procedure Clear(T: in out Table);

  procedure AddEntry(S: in Key; V: in Contents; T: in out Table);

  procedure ChangeEntry(S:in Key; V: in Contents; T:in out Table);

  function Retrieve(S:in Key; T:in Table) return Contents;

  function IsBound(S: in Key; T:in Table) return Boolean;

  function IsEmpty(T: in Table) return Boolean;

  function Size(T: in Table) return Natural;

  multiple_binding, entry_not_found, Table_overflow : exception;

private
  type binding is record
                    index: key;
                    value: contents;
                  end record;

  procedure Put(B: in Binding);		

  package bindlist is new list(binding);
  type Bucket is new bindlist.pointer;

  type tabarray is array (Positive range 1..NumberOfBuckets) of Bucket;
  type Table is access tabarray;

end HashTable;