--- ray/src/cv/mgflib/lookup.h	1994/06/21 14:45:40	1.1
+++ ray/src/cv/mgflib/lookup.h	1996/06/24 09:14:36	1.7
@@ -3,19 +3,40 @@
 /* SCCSid "$SunId$ LBL" */
 
 /*
- * Header file for table lookup routines
+ * Header file for general associative table lookup routines
  */
 
 typedef struct {
-	char	*key;		/* key name (dynamically allocated) */
+	char	*key;		/* key name */
+	long	hval;		/* key hash value (for efficiency) */
 	char	*data;		/* pointer to client data */
 } LUENT;
 
+#ifdef NOPROTO
 typedef struct {
+	long	(*hashf)();	/* key hash function */
+	int	(*keycmp)();	/* key comparison function */
+	void	(*freek)();	/* free a key */
+	void	(*freed)();	/* free the data */
 	int	tsiz;		/* current table size */
 	LUENT	*tabl;		/* table, if allocated */
+	int	ndel;		/* number of deleted entries */
 } LUTAB;
+#else
+typedef struct {
+	long	(*hashf)();	/* key hash function */
+	int	(*keycmp)(const char *, const char *);	/* key comparison function */
+	void	(*freek)(char *);	/* free a key */
+	void	(*freed)(char *);	/* free the data */
+	int	tsiz;		/* current table size */
+	LUENT	*tabl;		/* table, if allocated */
+	int	ndel;		/* number of deleted entries */
+} LUTAB;
+#endif
 
+#define LU_SINIT(fk,fd)		{lu_shash,strcmp,(void (*)())(fk),\
+				(void (*)())(fd),0,NULL,0}
+
 /*
  * The lu_init routine is called to initialize a table.  The number of
  * elements passed is not a limiting factor, as a table can grow to
@@ -24,32 +45,51 @@ typedef struct {
  * and the expected (minimum) table size.  The value returned is the
  * actual allocated table size (or zero if there was insufficient memory).
  *
- * It isn't fully necessary to initialize the LUTAB structure.  If it
- * is cleared (tsiz = 0, tabl = NULL), then the first call to lu_find
- * will allocate a minimal table.
+ * The hashf, keycmp, freek and freed member functions must be assigned
+ * separately.  If the hash value is sufficient to guarantee equality
+ * between keys, then the keycmp pointer may be NULL.  Otherwise, it
+ * should return 0 if the two passed keys match.  If it is not necessary
+ * (or possible) to free the key and/or data values, then the freek and/or
+ * freed member functions may be NULL.
  *
+ * It isn't fully necessary to call lu_init to initialize the LUTAB structure.
+ * If tsiz is 0, then the first call to lu_find will allocate a minimal table.
+ * The LU_SINIT macro provides a convenient static declaration for character
+ * string keys.
+ *
  * The lu_find routine returns the entry corresponding to the given
- * key (any nul-terminated string).  If the entry does not exist, the
- * corresponding key field will be NULL.  It is the caller's responsibility
- * to (allocate and) assign the key field when creating a new entry.
- * If an entry exists, the corresponding data field indicates whether
- * or not it contains data, and this, too, is subject to user control
- * and interpretation.  The only case where lu_find returns NULL is
- * when the system has run out of memory.
+ * key.  If the entry does not exist, the corresponding key field will
+ * be NULL.  If the entry has been previously deleted but not yet freed,
+ * then only the data field will be NULL.  It is the caller's
+ * responsibility to (allocate and) assign the key and data fields when
+ * creating a new entry.  The only case where lu_find returns NULL is when
+ * the system has run out of memory.
  *
+ * The lu_delete routine frees an entry's data (if any) by calling
+ * the freed member function, but does not free the key field.  This
+ * will be freed later during (or instead of) table reallocation.
+ * It is therefore an error to reuse or do anything with the key
+ * field after calling lu_delete.
+ *
  * The lu_done routine calls the given free function once for each
  * assigned table entry (i.e. each entry with an assigned key value).
- * The user must define this routine to free the key and the data
- * as appropriate.  The final action of lu_done is to free the
+ * The user must define these routines to free the key and the data
+ * in the LU_TAB structure.  The final action of lu_done is to free the
  * allocated table itself.
  */
 
 #ifdef NOPROTO
 extern int	lu_init();
 extern LUENT	*lu_find();
+extern void	lu_delete();
 extern void	lu_done();
+extern long	lu_shash();
+extern int	strcmp();
 #else
 extern int	lu_init(LUTAB *, int);
 extern LUENT	*lu_find(LUTAB *, char *);
-extern void	lu_done(LUTAB *, void (*)(LUENT *));
+extern void	lu_delete(LUTAB *, char *);
+extern void	lu_done(LUTAB *);
+extern long	lu_shash(char *);
+extern int	strcmp(char *, char *);
 #endif