/** \ingroup dbprim_hash
* \brief Find an entry in a hash table.
*
* This function looks up an entry matching the given \p key.
*
* \param table A pointer to a #hash_table_t.
* \param entry_p
* A pointer to a pointer to a #hash_entry_t. This is a
* result parameter. If \c NULL is passed, the lookup
* will be performed and an appropriate error code
* returned.
* \param key A pointer to a #db_key_t describing the item to find.
*
* \retval DB_ERR_BADARGS An argument was invalid.
* \retval DB_ERR_NOENTRY No matching entry was found.
*/
unsigned long
ht_find(hash_table_t *table, hash_entry_t **entry_p, db_key_t *key)
{
unsigned long hash;
link_elem_t *elem;
initialize_dbpr_error_table(); /* initialize error table */
if (!ht_verify(table) || !key) /* verify arguments */
return DB_ERR_BADARGS;
if (!table->ht_count) /* no entries in table... */
return DB_ERR_NOENTRY;
hash = (*table->ht_func)(table, key) % table->ht_modulus; /* get hash */
/* walk through each element in that section */
for (elem = ll_first(&table->ht_table[hash]); elem; elem = le_next(elem))
/* compare keys... */
if (!(*table->ht_comp)(table, key,
he_key((hash_entry_t *)le_object(elem)))) {
/* found one, return it */
if (entry_p)
*entry_p = le_object(elem);
return 0;
}
return DB_ERR_NOENTRY; /* couldn't find a matching entry */
}
/** \ingroup dbprim_hash
* \brief Iterate over each entry in a hash table.
*
* This function iterates over every entry in a hash table (in an
* unspecified order), executing the given \p iter_func on each entry.
*
* \param table A pointer to a #hash_table_t.
* \param iter_func
* A pointer to a callback function used to perform
* user-specified actions on an entry in a hash table. \c
* NULL is an invalid value. See the documentation for
* #hash_iter_t for more information.
* \param extra A \c void pointer that will be passed to \p
* iter_func.
*
* \retval DB_ERR_BADARGS An argument was invalid.
* \retval DB_ERR_FROZEN The hash table is frozen.
*/
unsigned long
ht_iter(hash_table_t *table, hash_iter_t iter_func, void *extra)
{
unsigned long retval;
int i;
link_elem_t *elem;
initialize_dbpr_error_table(); /* initialize error table */
if (!ht_verify(table) || !iter_func) /* verify arguments */
return DB_ERR_BADARGS;
if (table->ht_flags & HASH_FLAG_FREEZE) /* don't mess with frozen tables */
return DB_ERR_FROZEN;
table->ht_flags |= HASH_FLAG_FREEZE; /* freeze the table */
/* walk through all the elements and call the iteration function */
for (i = 0; i < table->ht_modulus; i++)
for (elem = ll_first(&table->ht_table[i]); elem; elem = le_next(elem))
if ((retval = (*iter_func)(table, le_object(elem), extra))) {
table->ht_flags &= ~HASH_FLAG_FREEZE; /* unfreeze the table */
return retval;
}
table->ht_flags &= ~HASH_FLAG_FREEZE; /* unfreeze the table */
return 0;
}
static unsigned long
_sh_flush_iter(link_head_t *head, link_elem_t *elem, void *extra)
{
unsigned long retval = 0;
struct _sh_flush_s *sf;
sf = extra;
/* Remove the object from all lists first */
if (_st_remove(sf->sf_table, le_object(elem), ST_REM_HASH |
(sf->sf_elem == SMAT_LOC_FIRST ? ST_REM_SECOND :
ST_REM_FIRST)))
return DB_ERR_UNRECOVERABLE;
/* call the user flush function if so desired */
if (sf->sf_flush)
retval = (*sf->sf_flush)(sf->sf_table, le_object(elem), sf->sf_extra);
_smat_free(le_object(elem)); /* destroy the entry */
return retval;
}
