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https://github.com/winterrdog/c-hash-map
this is a pure C project i took on to learn the details of how to implement a hash table aka hash map aka associative array.
https://github.com/winterrdog/c-hash-map
computer-science data-structures hash hashmap hashtable
Last synced: about 2 months ago
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this is a pure C project i took on to learn the details of how to implement a hash table aka hash map aka associative array.
- Host: GitHub
- URL: https://github.com/winterrdog/c-hash-map
- Owner: winterrdog
- License: mit
- Created: 2024-04-20T09:28:57.000Z (9 months ago)
- Default Branch: main
- Last Pushed: 2024-05-05T15:11:56.000Z (9 months ago)
- Last Synced: 2024-05-05T16:27:16.265Z (9 months ago)
- Topics: computer-science, data-structures, hash, hashmap, hashtable
- Language: C
- Homepage:
- Size: 37.1 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# ABOUT REPO
This is a hash table implementation in C with functions to _insert/update, search, create, get size,_ and _delete_ the hash table. It only operates on string keys and string values ONLY. It handles collisions using _open addressing with double hashing_ which is the most used technique for most production-level hash tables. The hash table is implemented using a _dynamic array_ so it can grow and shrink as needed based on the current load factor. Inspired by @jamesroutley's [implementation](https://github.com/jamesroutley/algorithms-and-data-structures/tree/master/hash-table). _I made drastic changes in some algorithms and fixed all memory bugs_.
No memory leaks or `OOB` writes are possible in this program ( _at least to the limit of my knowledge_ ), you can verify that with:
```sh
cd src && gcc -ggdb3 -fsanitize=address -o hash_table hash_table.c main.c prime.c xmalloc.c -lm
```
In short, this C program can be considered _memory-safe_.
## Requirements
- `gcc`
- Compatible with any operating system that supports `gcc`
## Hash Table C API
These are the functions provided by the hashmap as of now( all located in `src/hash_table.h` ):
```c
// custom types
typedef struct
{
const char* key;
const char* value;
} ht_item; // hash table entry -- represents a key-value pair
typedef struct
{
size_t size;
size_t base_size;
size_t count;
ht_item** items;
} ht_hash_table; // hash table structure -- represents the hash table
// function prototypes
ht_hash_table* ht_new(); // 'creates' new hash table
void ht_del_hash_table(ht_hash_table* t); // 'deletes' an existing hash table
void ht_insert(ht_hash_table* table, const char* k, const char* v); // 'inserts' a new key-value pair
void ht_delete(ht_hash_table* table, const char* k); // 'deletes' a key-value pair from the hash table
const char* ht_search(ht_hash_table* table, const char* k); // 'searches' for a key in the hash table
size_t ht_size(ht_hash_table* table); // get number of elements in hash table
```
## Usage
- Run the following command to compile the program:
```bash
./compile.sh
```
- Run the following command to execute the program:
```bash
./hash_table
```
This will run the driver program in `src/main.c` which demonstrates the usage of the hash table functions but it won't output anything to the console. You can modify the `main.c` file to test the hash table functions as you like. No output will indicate that the program ran successfully otherwise it will throw an error and exit.
## TODO
- Add support for multiple data types
## NOTE
This hashmap can be used in production-level code. It can be used as a good base to make another custom hash table.
For any issues or PRs you can always let me know.