Mastering Algorithms with C

Name

chtbl_init

Synopsis

int chtbl_init(CHTbl *htbl, int buckets, int (*h)(const void *key), 
   int (*match)(const void *key1, const void *key2), 
   void (*destroy)(void *data));

Return Value

0 if initializing the hash table is successful, or -1 otherwise.

Description

Initializes the chained hash table specified by htbl. This operation must be called for a chained hash table before the hash table can be used with any other operation. The number of buckets allocated in the hash table is specified by buckets. The function pointer h specifies a user-defined hash function for hashing keys. The function pointer match specifies a user-defined function to determine whether two keys match. It should return 1 if key1 is equal to key2, and otherwise. The destroy argument provides a way to free dynamically allocated data when chtbl_destroy is called. For example, if the hash table contains data dynamically allocated using malloc, destroy should be set to free to free the data as the hash table is destroyed. For structured data containing several dynamically allocated members, destroy should be set to a user-defined function that calls free for each dynamically allocated member as well as for the structure itself. For a hash table containing data that should not be freed, destroy should be set to NULL.

Complexity

O (m), where m is the number of buckets in the hash table.