NAME¶

libtar_hash_new, libtar_hash_free, libtar_hash_next, libtar_hash_prev, libtar_hash_getkey, libtar_hash_search, libtar_hash_add, libtar_hash_del - hash table routines

SYNOPSIS¶

#include <libtar.h>

libtar_hash_t *libtar_hash_new(int num, int (*hashfunc)());
void libtar_hash_free(libtar_hash_t *h, void (*freefunc)());
int libtar_hash_next(libtar_hash_t *h, libtar_hashptr_t *hp);
int libtar_hash_prev(libtar_hash_t *h, libtar_hashptr_t *hp);
int libtar_hash_search(libtar_hash_t *h, libtar_hashptr_t *hp, void *data, int (*matchfunc)());
int libtar_hash_getkey(libtar_hash_t *h, libtar_hashptr_t *hp, void *data, int (*matchfunc)());
int libtar_hash_add(libtar_hash_t *h, void *data);
int libtar_hash_del(libtar_hash_t *h, libtar_hashptr_t *hp);

DESCRIPTION¶

The libtar_hash_new() function creates a new hash with num buckets and using hash function pointed to by hashfunc. If hashfunc is NULL, a default hash function designed for 7-bit ASCII strings is used.

The libtar_hash_free() function deallocates all memory associated with the hash structure h. If freefunc is not NULL, it is called to free memory associated with each node in the hash.

The libtar_hash_next() and libtar_hash_prev() functions are used to iterate through the hash. The libtar_hashptr_t structure has two fields: bucket, which indicates the current bucket in the hash, and node, which is a pointer to the current node in the current bucket. To start at the beginning or end of the hash, the caller should initialize hp.bucket to -1 and hp.node to NULL.

The libtar_hash_search() function searches iteratively through the hash h until it finds a node whose contents match data using the matching function matchfunc. Searching begins at the location pointed to by hp.

The libtar_hash_getkey() function uses the hash function associated with h to determine which bucket data should be in, and searches only that bucket for a matching node using matchfunc. Searching begins at the location pointed to by hp.

The libtar_hash_add() function adds data into hash h.

The libtar_hash_del() function removes the node referenced by hp.

RETURN VALUE¶

The libtar_hash_new() function returns a pointer to the new hash structure, or NULL on error.

The libtar_hash_next() and libtar_hash_prev() functions return 1 when valid data is returned, and 0 at the end of the hash.

The libtar_hash_getkey() and libtar_hash_search() functions return 1 when a match is found, or 0 otherwise.

The libtar_hash_add() function returns 0 on success, or -1 on error (and sets errno).

The libtar_hash_del() function returns 0 on success, or -1 on error (and sets errno).

SEE ALSO¶

libtar_list_new(3)