/**
* Fetch an item with a given key value from the hash table
*
* @param table The hash table
* @param key The key value
* @return The item or NULL if the item was not found
*/
void *
hashtable_fetch(HASHTABLE *table, void *key)
{
unsigned int hashkey;
HASHENTRIES *entry;
if (table == NULL || key == NULL || 0 == table->hashsize)
{
return NULL;
}
hashkey = table->hashfn(key) % table->hashsize;
hashtable_read_lock(table);
entry = table->entries[hashkey % table->hashsize];
while (entry && entry->key && table->cmpfn(key, entry->key) != 0)
{
entry = entry->next;
}
if (entry == NULL)
{
hashtable_read_unlock(table);
return NULL;
}
else
{
hashtable_read_unlock(table);
return entry->value;
}
}
/**
* Return the next key for a hashtable iterator
*
* @param iter The hashtable iterator
* @return The next key value or NULL
*/
void *
hashtable_next(HASHITERATOR *iter)
{
int i;
HASHENTRIES *entries;
iter->depth++;
while (iter->chain < iter->table->hashsize)
{
if ((entries = iter->table->entries[iter->chain]) != NULL)
{
i = 0;
hashtable_read_lock(iter->table);
while (entries && i < iter->depth)
{
entries = entries->next;
i++;
}
hashtable_read_unlock(iter->table);
if (entries)
return entries->key;
}
iter->depth = 0;
iter->chain++;
}
return NULL;
}
/**
* Produces stat output about hashtable
*
* Parameters:
* @param table - <usage>
* <description>
*
* @param hashsize - <usage>
* <description>
*
* @param nelems - <usage>
* <description>
*
* @param longest - <usage>
* <description>
*
* @return void
*
*
*/
void hashtable_get_stats(
void* table,
int* hashsize,
int* nelems,
int* longest)
{
HASHTABLE* ht;
HASHENTRIES* entries;
int i;
int j;
ht = (HASHTABLE *)table;
CHK_HASHTABLE(ht);
*nelems = 0;
*longest = 0;
hashtable_read_lock(ht);
for (i = 0; i < ht->hashsize; i++)
{
j = 0;
entries = ht->entries[i];
while (entries)
{
j++;
entries = entries->next;
}
*nelems += j;
if (j > *longest) {
*longest = j;
}
}
*hashsize = ht->hashsize;
hashtable_read_unlock(ht);
}
/**
* Print hash table statistics to the standard output
*
* @param table The hash table
*/
void
hashtable_stats(HASHTABLE *table)
{
int total, longest, i, j;
HASHENTRIES *entries;
printf("Hashtable: %p, size %d\n", table, table->hashsize);
total = 0;
longest = 0;
hashtable_read_lock(table);
for (i = 0; i < table->hashsize; i++)
{
j = 0;
entries = table->entries[i];
while (entries)
{
j++;
entries = entries->next;
}
total += j;
if (j > longest)
longest = j;
}
hashtable_read_unlock(table);
printf("\tNo. of entries: %d\n", total);
printf("\tAverage chain length: %.1f\n", (float)total / table->hashsize);
printf("\tLongest chain length: %d\n", longest);
}