src/common/lookup.h

/* RCSid $Id: lookup.h,v 2.10 2003/07/14 22:23:59 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:	2.11
Committed:	Wed Jul 30 10:11:06 2003 UTC (20 years, 9 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.10:	+10 -8 lines
Log Message:	Added prototypes submitted by Randolph Fritz.
#	User	Rev	Content
1	schorsch	2.11	/* RCSid $Id: lookup.h,v 2.10 2003/07/14 22:23:59 schorsch 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	schorsch	2.11	typedef void lut_free_t(void*);
15
16	greg	2.1	typedef struct {
17	gwlarson	2.5	char key; / key name */
18			unsigned long hval; /* key hash value (for efficiency) */
19			char data; / pointer to client data */
20	greg	2.1	} LUENT;
21
22			typedef struct {
23	schorsch	2.11	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	gwlarson	2.5	int tsiz; /* current table size */
28			LUENT tabl; / table, if allocated */
29			int ndel; /* number of deleted entries */
30	greg	2.1	} LUTAB;
31
32	gregl	2.3	#undef strcmp
33	schorsch	2.11	#define LU_SINIT(fk,fd) {lu_shash,strcmp,fk,\
34			fd,0,NULL,0}
35	greg	2.1
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	greg	2.2	* It is therefore an error to reuse or do anything with the key
68			* field after calling lu_delete.
69	greg	2.1	*
70	gwlarson	2.4	* 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	greg	2.1	* 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	greg	2.6
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	schorsch	2.11	extern int lu_doall(LUTAB tbl, int (f)(LUENT*));
88	greg	2.6	extern void lu_done(LUTAB *tbl);
89
90	schorsch	2.8
91			#ifdef __cplusplus
92			}
93	greg	2.6	#endif
94	schorsch	2.8	#endif /* _RAD_LOOKUP_H_ */
95