C Hash Table Implementation (Based on Ben Hoyt's Tutorial)

This repository contains a simple, efficient hash table implementation in C that follows Ben Hoyt's excellent Build Your Own Hash Table in C tutorial. The purpose of this project is educational: to understand low-level data structure design and memory management in C by building a hash table from scratch.

💡 This implementation was directly inspired by and adapted from Ben Hoyt’s original work. All credit for the design and guiding principles belongs to him.

📦 Features

• Uses open addressing with linear probing for collision resolution.
• Automatically expands the table when it's more than half full.
• Stores key-value pairs where:
  • Keys are const char* (strings, copied via strdup)
  • Values are void* (user-provided pointers)
• Iteration support via a simple iterator type.
• Uses the FNV-1a hash function for good distribution and speed.

📚 File Structure

File	Description
ht.c	Implementation of the hash table (ht) and its iterator (hti)
ht.h	Public interface for using the hash table
main.c	Optional: your test/demo file goes here
README.md	This file

🛠️ How It Works

• ht_create: Allocates and initializes an empty hash table.
• ht_set: Inserts a key–value pair. Expands the table if it becomes more than half full.
• ht_get: Looks up a key and returns the corresponding value.
• ht_destroy: Frees all allocated memory — including the keys.
• ht_iterator / it_next: Iterates through all items in the hash table.

Internally, the hash table keeps an array of ht_entry structs. Each ht_entry stores a key and value. When inserting, it uses the FNV-1a hash of the key to find the initial slot and then probes forward until it finds an empty slot or an existing matching key.

🔁 Example Usage

ht* table = ht_create();
ht_set(table, "name", "Mateo");
ht_set(table, "language", "C");

printf("%s\n", (char*)ht_get(table, "name"));  // Output: Mateo

ht_destroy(table);

To iterate:

hti it = ht_iterator(table);
while (it_next(&it)) {
    printf("%s => %s\n", it.key, (char*)it.value);
}

📎 Credit

This project is a derivative and learning-based reimplementation of:

Ben Hoyt, Build Your Own Hash Table in C

Ben graciously released his work under the public domain. This adaptation is shared in that same spirit — to educate and encourage low-level programming skills.

📜 License

This project is released under the terms of the MIT License, with credit to Ben Hoyt for the original tutorial and inspiration.