| 1 |
/* RCSid: $Id$ */ |
| 2 |
/* |
| 3 |
* Header file for general associative table lookup routines |
| 4 |
*/ |
| 5 |
|
| 6 |
typedef struct { |
| 7 |
char *key; /* key name */ |
| 8 |
long hval; /* key hash value (for efficiency) */ |
| 9 |
char *data; /* pointer to client data */ |
| 10 |
} LUENT; |
| 11 |
|
| 12 |
#ifdef NOPROTO |
| 13 |
typedef struct { |
| 14 |
unsigned long (*hashf)(); /* key hash function */ |
| 15 |
int (*keycmp)(); /* key comparison function */ |
| 16 |
void (*freek)(); /* free a key */ |
| 17 |
void (*freed)(); /* free the data */ |
| 18 |
int tsiz; /* current table size */ |
| 19 |
LUENT *tabl; /* table, if allocated */ |
| 20 |
int ndel; /* number of deleted entries */ |
| 21 |
} LUTAB; |
| 22 |
#else |
| 23 |
typedef struct { |
| 24 |
unsigned long (*hashf)(char *); /* key hash function */ |
| 25 |
int (*keycmp)(const char *, const char *); /* key comparison function */ |
| 26 |
void (*freek)(char *); /* free a key */ |
| 27 |
void (*freed)(char *); /* free the data */ |
| 28 |
int tsiz; /* current table size */ |
| 29 |
LUENT *tabl; /* table, if allocated */ |
| 30 |
int ndel; /* number of deleted entries */ |
| 31 |
} LUTAB; |
| 32 |
#endif |
| 33 |
|
| 34 |
#define LU_SINIT(fk,fd) {lu_shash,strcmp,(void (*)())(fk),\ |
| 35 |
(void (*)())(fd),0,NULL,0} |
| 36 |
|
| 37 |
/* |
| 38 |
* The lu_init routine is called to initialize a table. The number of |
| 39 |
* elements passed is not a limiting factor, as a table can grow to |
| 40 |
* any size permitted by memory. However, access will be more efficient |
| 41 |
* if this number strikes a reasonable balance between default memory use |
| 42 |
* and the expected (minimum) table size. The value returned is the |
| 43 |
* actual allocated table size (or zero if there was insufficient memory). |
| 44 |
* |
| 45 |
* The hashf, keycmp, freek and freed member functions must be assigned |
| 46 |
* separately. If the hash value is sufficient to guarantee equality |
| 47 |
* between keys, then the keycmp pointer may be NULL. Otherwise, it |
| 48 |
* should return 0 if the two passed keys match. If it is not necessary |
| 49 |
* (or possible) to free the key and/or data values, then the freek and/or |
| 50 |
* freed member functions may be NULL. |
| 51 |
* |
| 52 |
* It isn't fully necessary to call lu_init to initialize the LUTAB structure. |
| 53 |
* If tsiz is 0, then the first call to lu_find will allocate a minimal table. |
| 54 |
* The LU_SINIT macro provides a convenient static declaration for character |
| 55 |
* string keys. |
| 56 |
* |
| 57 |
* The lu_find routine returns the entry corresponding to the given |
| 58 |
* key. If the entry does not exist, the corresponding key field will |
| 59 |
* be NULL. If the entry has been previously deleted but not yet freed, |
| 60 |
* then only the data field will be NULL. It is the caller's |
| 61 |
* responsibility to (allocate and) assign the key and data fields when |
| 62 |
* creating a new entry. The only case where lu_find returns NULL is when |
| 63 |
* the system has run out of memory. |
| 64 |
* |
| 65 |
* The lu_delete routine frees an entry's data (if any) by calling |
| 66 |
* the freed member function, but does not free the key field. This |
| 67 |
* will be freed later during (or instead of) table reallocation. |
| 68 |
* It is therefore an error to reuse or do anything with the key |
| 69 |
* field after calling lu_delete. |
| 70 |
* |
| 71 |
* The lu_done routine calls the given free function once for each |
| 72 |
* assigned table entry (i.e. each entry with an assigned key value). |
| 73 |
* The user must define these routines to free the key and the data |
| 74 |
* in the LU_TAB structure. The final action of lu_done is to free the |
| 75 |
* allocated table itself. |
| 76 |
*/ |
| 77 |
|
| 78 |
#ifdef NOPROTO |
| 79 |
extern int lu_init(); |
| 80 |
extern LUENT *lu_find(); |
| 81 |
extern void lu_delete(); |
| 82 |
extern void lu_done(); |
| 83 |
extern unsigned long lu_shash(); |
| 84 |
#else |
| 85 |
extern int lu_init(LUTAB *, int); |
| 86 |
extern LUENT *lu_find(LUTAB *, char *); |
| 87 |
extern void lu_delete(LUTAB *, char *); |
| 88 |
extern void lu_done(LUTAB *); |
| 89 |
extern unsigned long lu_shash(char *); |
| 90 |
#endif |
