Grsaiago / hashmapC

This is my implementation of a hashmap in C

C Hash Table

This is my implementation of a hashmap in C

Installation

Although this project wasn't made to be used, if you want to, you just have to clone this repo and copy the only file into your project src folder

cp hashmap.c <path to your C source files>

Usage/Examples

int main(void) {
    struct s_hash_table    *table;
    void                    *str;

    table = malloc_table(10); // First you have to allocate the hash table.
    str = strdup("example_value");  // creating a sample value.
    table_insert(table, "example_key", str); // inserting is easy as passing the key and a pointer to the value.
    printf("%s\n", (char *)table_access(table, "key")); // accessing is as easy as passing the key you want to access.
    freeTable(table); // don't forget to free the requested memory, just as in malloc/free api ;)
}

Roadmap

• Colision resolution.

• Make the internal array into a vector to allow dynamic growth of size.

• Implement a decent hashing algorithm

Documentation

struct s_hash_table *malloc_table(unsigned int size, void (*free_func)(void *))

Description: Creates an instance of the hashTable with initial size ammount of buckets.

Parameters:

• size: The initial size of the hash table.
• free_func: A pointer to a function that frees the data structure you're going to store as the value in the table. This is used in the table destruction, to ensure that there is no data leaks.

Return: A hash table instance.

void free_table(struct s_hash_table *table)

Description: Frees the table instance and calls the free_func on every existing bucket.

Parameters:

• table: The hash table to be freed.

• Return: n/a

struct void *tableInsert(struct s_hash_table *table, char *key, void *value)

Description: Inserts in the given table the value value with key as the access key to said value.

Parameters:

• table: The hash table to be operated on.
• key: A string that will become the key of the new bucket.
• value: The new value to be associated with the key and inserted in the bucket.

Return: the inserted value

int table_remove(void *table, char *key)

Description: Calls the free_func on the value assotiated with key, and delete said key.

Parameters:

• table: The hash table to be operated on.
• key: A string that has the same name as a key in the hash table.

Return: 0 if the value existed before being deleted, 1 otherwise.

void *table_access(struct s_hash_table *table, char *key)

Description: Retrieves from table the value associated with key - if so exists.

Parameters:

• table: the table to be operated on.
• key: A string that has the same name as a key in the hash table.

Return: A pointer to the associated value of the key/value pair or NULL if key doesn't exist on table