cv/mgflib/lookup.h

/* RCSid $Id: lookup.h,v 2.11 2003/07/30 10:11:06 schorsch 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 void lut_free_t(void*);

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)(char*);  /* key hash function */
        int (*keycmp)(const char*, const char*);        /* key comparison function */
        lut_free_t *freek;              /* free a key */
        lut_free_t *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,fk,\
                                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)(LUENT*));
extern void     lu_done(LUTAB *tbl);


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

Revision:	1.12
Committed:	Sat Nov 15 17:54:06 2003 UTC (20 years, 11 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R7P1, rad4R0, rad3R6, rad3R6P1, rad3R8, rad3R9, rad3R7P2
Changes since 1.11:	+33 -21 lines
Log Message:	Continued ANSIfication and reduced compile warnings.
#	Content
1	/* RCSid $Id: lookup.h,v 2.11 2003/07/30 10:11:06 schorsch Exp $ */
2	/*
3	* Header file for general associative table lookup routines
4	*/
5	#ifndef _RAD_LOOKUP_H_
6	#define _RAD_LOOKUP_H_
7
8	#include <string.h> /* strcmp() */
9
10	#ifdef __cplusplus
11	extern "C" {
12	#endif
13
14	typedef void lut_free_t(void*);
15
16	typedef struct {
17	char key; / key name */
18	unsigned long hval; /* key hash value (for efficiency) */
19	char data; / pointer to client data */
20	} LUENT;
21
22	typedef struct {
23	unsigned long (hashf)(char); /* key hash function */
24	int (keycmp)(const char, const char); / key comparison function */
25	lut_free_t freek; / free a key */
26	lut_free_t freed; / free the data */
27	int tsiz; /* current table size */
28	LUENT tabl; / table, if allocated */
29	int ndel; /* number of deleted entries */
30	} LUTAB;
31
32	#undef strcmp
33	#define LU_SINIT(fk,fd) {lu_shash,strcmp,fk,\
34	fd,0,NULL,0}
35
36	/*
37	* The lu_init routine is called to initialize a table. The number of
38	* elements passed is not a limiting factor, as a table can grow to
39	* any size permitted by memory. However, access will be more efficient
40	* if this number strikes a reasonable balance between default memory use
41	* and the expected (minimum) table size. The value returned is the
42	* actual allocated table size (or zero if there was insufficient memory).
43	*
44	* The hashf, keycmp, freek and freed member functions must be assigned
45	* separately. If the hash value is sufficient to guarantee equality
46	* between keys, then the keycmp pointer may be NULL. Otherwise, it
47	* should return 0 if the two passed keys match. If it is not necessary
48	* (or possible) to free the key and/or data values, then the freek and/or
49	* freed member functions may be NULL.
50	*
51	* It isn't fully necessary to call lu_init to initialize the LUTAB structure.
52	* If tsiz is 0, then the first call to lu_find will allocate a minimal table.
53	* The LU_SINIT macro provides a convenient static declaration for character
54	* string keys.
55	*
56	* The lu_find routine returns the entry corresponding to the given
57	* key. If the entry does not exist, the corresponding key field will
58	* be NULL. If the entry has been previously deleted but not yet freed,
59	* then only the data field will be NULL. It is the caller's
60	* responsibility to (allocate and) assign the key and data fields when
61	* creating a new entry. The only case where lu_find returns NULL is when
62	* the system has run out of memory.
63	*
64	* The lu_delete routine frees an entry's data (if any) by calling
65	* the freed member function, but does not free the key field. This
66	* will be freed later during (or instead of) table reallocation.
67	* It is therefore an error to reuse or do anything with the key
68	* field after calling lu_delete.
69	*
70	* The lu_doall routine loops through every filled table entry, calling
71	* the given function once on each entry. If a NULL pointer is passed
72	* for this function, then lu_doall simply returns the total number of
73	* active entries. Otherwise, it returns the sum of all the function
74	* evaluations.
75	*
76	* The lu_done routine calls the given free function once for each
77	* assigned table entry (i.e. each entry with an assigned key value).
78	* The user must define these routines to free the key and the data
79	* in the LU_TAB structure. The final action of lu_done is to free the
80	* allocated table itself.
81	*/
82
83	extern int lu_init(LUTAB *tbl, int nel);
84	extern unsigned long lu_shash(char *s);
85	extern LUENT lu_find(LUTAB tbl, char *key);
86	extern void lu_delete(LUTAB tbl, char key);
87	extern int lu_doall(LUTAB tbl, int (f)(LUENT*));
88	extern void lu_done(LUTAB *tbl);
89
90
91	#ifdef __cplusplus
92	}
93	#endif
94	#endif /* _RAD_LOOKUP_H_ */
95