/***************************  hashing-bool-ops.h  *****************************

  Purpose:	External declarations for boolean operations implemented
  		using hashing.

  Provenance:	Written and tested by S. Wartik, April 1991.

  Notes:	None.

**/

#ifndef TRUE
#   define TRUE 1
#   define FALSE 0
    typedef int boolean;
#endif

typedef int	elementType;	    /* This could be any valid type.	  */

typedef struct be_str {		    /* A link in the chain from a bucket. */
    elementType     datum;	    /* Implemented as a linked list.	  */
    struct be_str   *next_datum;
} bucket_element;

typedef struct {		/* A hashing-based set implementation. */
    int             Number_Of_Buckets;
    bucket_element  **buckets;
    int             (*hashing_function)(); /* The set's hashing function.    */
    boolean         (*comparator)();	   /* A tester for element equality. */
} set;

#ifdef __STDC__

extern void Create(int Number_Of_Buckets,
		   int (*Hashing_Function)(),
		   boolean (*Comparator)(),
		   set *s);

extern void Clear(set *s);
extern void Insert(set *s, elementType e);
extern void Delete(set *s, elementType e);

extern void Unite(set *s1, set *s2, set *s3);
extern void Intersect(set *s1, set *s2, set *s3);
extern void Subtract(set *s1, set *s2, set *s3);

extern boolean Empty(set *s);
extern boolean Member(set *s, elementType e);

extern void Copy(set *source, set *destination);

extern void Iterate(set *s, boolean (*f)());

boolean Error_Occurred();

#else

extern void Create();		/* Create a set.			*/

extern void Clear();		/* Make a set contain zero elements.	*/
extern void Insert();		/* Insert an element into a set.	*/
extern void Delete();		/* Remove an element from a set.	*/

extern void Unite();		/* Form the union of two sets.		*/
extern void Intersect();	/* Form the intersection of two sets.	*/
extern void Subtract();		/* Form the difference of two sets.	*/

extern boolean Empty();		/* Return TRUE iff a set has zero elements. */
extern boolean Member();	/* Return TRUE iff a specified value is	*/
				/* a member of a set.			*/

extern void Copy();		/* Make a copy of a set.		*/

extern void Iterate();		/* Invoke a function on every element	*
				/* in a set.				*/

extern boolean Error_Occurred(); /* Return TRUE iff the last		*/
				 /* operation caused an error.		*/
#endif