src/common/lookup.h

/* RCSid $Id: lookup.h,v 2.9 2003/06/27 06:53:21 greg Exp $ */
/*
 * Header file for general associative table lookup routines
 */
#ifndef _RAD_LOOKUP_H_
#define _RAD_LOOKUP_H_

#include <string.h> /* strcmp() */

#ifdef __cplusplus
extern "C" {
#endif

typedef struct {
        char    *key;                   /* key name */
        unsigned long   hval;           /* key hash value (for efficiency) */
        char    *data;                  /* pointer to client data */
} LUENT;

typedef struct {
        unsigned 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;

#undef strcmp
#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
 * any size permitted by memory.  However, access will be more efficient
 * if this number strikes a reasonable balance between default memory use
 * and the expected (minimum) table size.  The value returned is the
 * actual allocated table size (or zero if there was insufficient memory).
 *
 * 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.  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_doall routine loops through every filled table entry, calling
 * the given function once on each entry.  If a NULL pointer is passed
 * for this function, then lu_doall simply returns the total number of
 * active entries.  Otherwise, it returns the sum of all the function
 * evaluations.
 *
 * 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 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.
 */

extern int      lu_init(LUTAB *tbl, int nel);
extern unsigned long    lu_shash(char *s);
extern LUENT    *lu_find(LUTAB *tbl, char *key);
extern void     lu_delete(LUTAB *tbl, char *key);
extern int      lu_doall(LUTAB *tbl, int (*f)());
extern void     lu_done(LUTAB *tbl);


#ifdef __cplusplus
}
#endif
#endif /* _RAD_LOOKUP_H_ */

Revision:	2.10
Committed:	Mon Jul 14 22:23:59 2003 UTC (20 years, 9 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.9:	+4 -3 lines
Log Message:	Instrumented headers against multiple inclusion and for use from C++. Moved includes in headers out of "C" scope.
#	User	Rev	Content
1	schorsch	2.10	/* RCSid $Id: lookup.h,v 2.9 2003/06/27 06:53:21 greg Exp $ */
2	greg	2.1	/*
3			* Header file for general associative table lookup routines
4			*/
5	schorsch	2.8	#ifndef _RAD_LOOKUP_H_
6			#define _RAD_LOOKUP_H_
7	schorsch	2.10
8			#include <string.h> /* strcmp() */
9
10	schorsch	2.8	#ifdef __cplusplus
11			extern "C" {
12			#endif
13	greg	2.6
14	greg	2.1	typedef struct {
15	gwlarson	2.5	char key; / key name */
16			unsigned long hval; /* key hash value (for efficiency) */
17			char data; / pointer to client data */
18	greg	2.1	} LUENT;
19
20			typedef struct {
21	gwlarson	2.5	unsigned long (hashf)(); / key hash function */
22			int (keycmp)(); / key comparison function */
23			void (freek)(); / free a key */
24			void (freed)(); / free the data */
25			int tsiz; /* current table size */
26			LUENT tabl; / table, if allocated */
27			int ndel; /* number of deleted entries */
28	greg	2.1	} LUTAB;
29
30	gregl	2.3	#undef strcmp
31	greg	2.1	#define LU_SINIT(fk,fd) {lu_shash,strcmp,(void (*)())(fk),\
32			(void (*)())(fd),0,NULL,0}
33
34			/*
35			* The lu_init routine is called to initialize a table. The number of
36			* elements passed is not a limiting factor, as a table can grow to
37			* any size permitted by memory. However, access will be more efficient
38			* if this number strikes a reasonable balance between default memory use
39			* and the expected (minimum) table size. The value returned is the
40			* actual allocated table size (or zero if there was insufficient memory).
41			*
42			* The hashf, keycmp, freek and freed member functions must be assigned
43			* separately. If the hash value is sufficient to guarantee equality
44			* between keys, then the keycmp pointer may be NULL. Otherwise, it
45			* should return 0 if the two passed keys match. If it is not necessary
46			* (or possible) to free the key and/or data values, then the freek and/or
47			* freed member functions may be NULL.
48			*
49			* It isn't fully necessary to call lu_init to initialize the LUTAB structure.
50			* If tsiz is 0, then the first call to lu_find will allocate a minimal table.
51			* The LU_SINIT macro provides a convenient static declaration for character
52			* string keys.
53			*
54			* The lu_find routine returns the entry corresponding to the given
55			* key. If the entry does not exist, the corresponding key field will
56			* be NULL. If the entry has been previously deleted but not yet freed,
57			* then only the data field will be NULL. It is the caller's
58			* responsibility to (allocate and) assign the key and data fields when
59			* creating a new entry. The only case where lu_find returns NULL is when
60			* the system has run out of memory.
61			*
62			* The lu_delete routine frees an entry's data (if any) by calling
63			* the freed member function, but does not free the key field. This
64			* will be freed later during (or instead of) table reallocation.
65	greg	2.2	* It is therefore an error to reuse or do anything with the key
66			* field after calling lu_delete.
67	greg	2.1	*
68	gwlarson	2.4	* The lu_doall routine loops through every filled table entry, calling
69			* the given function once on each entry. If a NULL pointer is passed
70			* for this function, then lu_doall simply returns the total number of
71			* active entries. Otherwise, it returns the sum of all the function
72			* evaluations.
73			*
74	greg	2.1	* The lu_done routine calls the given free function once for each
75			* assigned table entry (i.e. each entry with an assigned key value).
76			* The user must define these routines to free the key and the data
77			* in the LU_TAB structure. The final action of lu_done is to free the
78			* allocated table itself.
79			*/
80	greg	2.6
81			extern int lu_init(LUTAB *tbl, int nel);
82			extern unsigned long lu_shash(char *s);
83			extern LUENT lu_find(LUTAB tbl, char *key);
84			extern void lu_delete(LUTAB tbl, char key);
85			extern int lu_doall(LUTAB tbl, int (f)());
86			extern void lu_done(LUTAB *tbl);
87
88	schorsch	2.8
89			#ifdef __cplusplus
90			}
91	greg	2.6	#endif
92	schorsch	2.8	#endif /* _RAD_LOOKUP_H_ */
93