libtar_hash_new(3)						  C Library Calls						libtar_hash_new(3)

NAME

       libtar_hash_new,  libtar_hash_free,  libtar_hash_next,  libtar_hash_prev,  libtar_hash_getkey,  libtar_hash_search,  libtar_hash_add,  lib-
       tar_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  match-
       ing 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)

University of Illinois						     Jan 2000							libtar_hash_new(3)