int needed_size = prime_size (ht->count * 3);
ht->size = MAX (old_size, needed_size);
int needed_size = prime_size (ht->count * 3);
ht->size = MAX (old_size, needed_size);
ht->mappings = xmalloc (ht->size * sizeof (struct mapping));
memset (ht->mappings, '\0', ht->size * sizeof (struct mapping));
ht->mappings = xmalloc (ht->size * sizeof (struct mapping));
memset (ht->mappings, '\0', ht->size * sizeof (struct mapping));