Cuckoo Hashing

An implementation of a hashmap in c using cuckoo hashing and a hashing algorithm based off md5 sums

Upsizes map when population is larger than 70% of the capacity of the hashtable
Downsizes when population is smaller than 30% of the capacity of the hashtable

Usage

Create cuckoo_table struct
Call init_cuckoo_table and pass the address of this struct
Use insert, delete and lookup for adding key value pairs, searching for key value pairs and deleting key value pairs
Call del_cuckoo_table to cleanup memory

Functions

void init_cuckoo_table(struct cuckoo_table *map)
Initialises cuckoo table and allocates memory
Parameters:

• map: address of cuckoo_table struct to initialise

Return value:

• void

void del_cuckoo_table(struct cuckoo_table *map)
Frees memory of cuckoo table struct allocated by init
Parameters:

• map: address of cuckoo_table to destruct

Return value:

• void

int insert(struct cuckoo_table *map, char *key, int value)
Inserts key value pair into map
Parameters:

• map: address of cuckoo_table struct to perform insert
• key: key to insert
• value: value to insert

Return value:

• RET_SUCCESS on successful insertion
• RET_FAILURE if key already exists

int lookup(struct cuckoo_table *map, const char *key, int *value_rv)
performs lookup on key in map, setting value_rv to be the corresponding value if a corresponding key exists and value_rv != NULL
Parameters:

• map: address of cuckoo_table struct to perform lookup within
• key: key to lookup
• value_rv: address of integer to store result

Return value:

• RET_SUCCESS on successful return
• RET_FAILURE if key is not found

int delete(struct cuckoo_table *map, char *key)
Deletes key from map if such a key exists
Parameters:

• map: address of cuckoo_table struct to perform deletion
• key: key to remove

Return value:

• RET_SUCCESS on successful deletion
• RET_FAILURE if key did not exist