rohanrhu / libhash

A fast and efficient non-iterating hashmap library

libhash: a fast and efficient non-iterating hashmap library

Libhash is a fast and efficient non-iterating hashmap library

Usage

Usage is easy and simple. You can look to examples/ directory. You can build examples with make command.

Including

#include "libhash/include/libhash.h"

Building with source

gcc -o application libhash/src/libhash.c application.c

Linking libhash.o

Build libhash:

make

and use libhash.o:

gcc -o application application.c libhash/libhash.o

Simple Hashmap

Here is an example for simple hashmap.

#include <stdio.h>

#include "libhash/include/libhash.h"

int main() {
    libhash_t* movies = libhash_init();
    libhash_set(movies, "Alien", "The best movie ever!");
    libhash_set(movies, "Prometheus", "The worst movie ever!");
    libhash_set(movies, "こんにちは世界", "Hello World!");

    libhash_node_t* alien = libhash_get(movies, "Alien");
    libhash_node_t* prometheus = libhash_get(movies, "Prometheus");
    libhash_node_t* hello = libhash_get(movies, "こんにちは世界");

    hello && printf("こんにちは世界: %s\n", hello->value);
    alien && printf("Alien: %s\n", alien->value);
    prometheus && printf("Prometheus: %s\n", prometheus->value);

    libhash_free(movies);

    return 0;
}

Hash Algorithm

It hashes NULL-terminated strings (I was lazy for making another binary one that works with length lol...) to 32-bit unsigned scalars.

I made some tests about conflictions and it looked oki. And I just made this hash algorithm in a coffee break and note sure how decent it is.

UTF-8 Support

Since I added hashing feature it always uses unsigned char indexes and support UTF-8.

Benchmark

There is a benchmark in examples/benchmark directory. You can just do:

cd examples/benchmark
make clean; make; ./benchmark

Functions

libhash_t* libhash_init()

Creates a hashmap.

libhash_node_t* libhash_set(libhash_t* hashmap, char* key, void* value)

Sets a key-value pair and returns the node.

void libhash_unset(libhash_t* hashmap, char* key)

Unsets a key-value pair.

libhash_node_t* libhash_get(libhash_t* hashmap, char* key)

Gets the value of key.

void libhash_free(libhash_t* hashmap)

Frees hashmap.

void libhash_node_free(libhash_node_t* node)

Frees node.

uint32_t libhash_hash32(char* str)

Accepts NULL-terminated string and returns a 32-bit unsigned scalar hash.

Types

libhash_t

The hashmap type.

typedef struct libhash libhash_t;
struct libhash {
    libhash_node_t* root;
};

libhash_node_t

typedef struct libhash_node libhash_node_t;
struct libhash_node {
    libhash_node_t* map[256];
    libhash_node_t* parent;
    void* value;
    int len;
};

License

Copyright (c) 2021 Oğuzhan Eroğlu [e-mail] (https://oguzhaneroglu.com). All rights reserved.

This work is licensed under the terms of the MIT license.
For a copy, see https://opensource.org/licenses/MIT.