libpear 🍐

A lightweight hash table library written in C, built from scratch. Supports key-value pair storage with double hashing for collision resolution and dynamic resizing.

Table of contents

• Requirements
• Installation
• Usage
• API
• How it works
• Maintainers

Requirements

• GCC
• Make

Installation

1. Clone the repository:

git clone https://github.com/Peposg/libpear.git
cd libpear

2. Build the static library:

make build

This compiles src/libpear.c into a static library libpear.a.

Usage

Include the header in your program:

#include "libpear.h"

Compile your program against the library:

gcc -I src your_file.c -L. -lpear -lm -o output

Or use the test target with your file:

make test FILE=your_file.c

API

// Create a new hash table
pear_t* pt_new();

// Delete a hash table and free all memory
void pt_delete(pear_t* pt);

// Insert a key-value pair
void insert_p(pear_t* pt, char* key, char* value);

// Search for a value by key — returns NULL if not found
char* search_p(pear_t* pt, char* key);

// Delete a key-value pair — returns 0 on success, 1 if not found
int delete_p(pear_t* pt, char* key);

// Resize the hash table to a new capacity
pear_t* pt_resize(pear_t* pt, int new_size);

Example

pear_t* pt = pt_new();

insert_p(pt, "name", "alice");
insert_p(pt, "city", "london");

char* result = search_p(pt, "name");  // returns "alice"

delete_p(pt, "city");

pt_delete(pt);

How it works

• Keys and values are stored as strings (char*)
• The table uses double hashing to resolve collisions, using two different prime numbers (151 and 163) to calculate slot indices
• The default table size is 53 (a prime number chosen for even distribution)
• The table can be manually resized with pt_resize

Maintainers

• Sam - Peposg