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)

University of Illinois                              Jan 2000                                  libtar_hash_new(3)