Libft

Libft is a custom library written in C as part of the 42 London curriculum. It replicates a selection of standard C library functions and introduces additional functionality for handling linked lists. The project is designed to reinforce understanding of memory allocation, string manipulation, and data structures.

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Table of Contents

1. Introduction
2. Mandatory Functions
3. Bonus Functions
4. Usage
5. Compilation
6. License

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Introduction

The Libft project involves recreating functions from the standard C library (libc) as well as implementing additional utility functions. It is divided into two parts:

• Mandatory Part: Reimplement common standard C functions.
• Bonus Part: Create a set of functions to manipulate linked lists.

This library can be reused in future 42 projects.

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Mandatory Functions

Standard C Library Replications

The following functions are implemented in the mandatory part of the project:

Function Name	Description
isalpha	Checks if a character is alphabetic.
isdigit	Checks if a character is a digit.
isalnum	Checks if a character is alphanumeric.
isascii	Checks if a character is an ASCII character.
isprint	Checks if a character is printable.
strlen	Returns the length of a string.
memset	Fills memory with a constant byte.
bzero	Zeros out a block of memory.
memcpy	Copies memory from one location to another.
memmove	Copies memory, handling overlapping regions safely.
strlcpy	Copies a string with size limiting.
strlcat	Concatenates two strings with size limiting.
toupper	Converts a character to uppercase.
tolower	Converts a character to lowercase.
strchr	Locates the first occurrence of a character in a string.
strrchr	Locates the last occurrence of a character in a string.
strncmp	Compares two strings up to a specified number of characters.
memchr	Searches memory for a specific byte.
memcmp	Compares two blocks of memory.
strnstr	Locates a substring within a string, up to a given length.
atoi	Converts a string to an integer.

Additional Memory Management Functions

These functions use malloc for dynamic memory allocation:

Function Name	Description
calloc	Allocates and zeroes out memory.
strdup	Duplicates a string by allocating memory for the copy.

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Bonus Functions

In the bonus part of the project, the following linked list functions were implemented:

Function Name	Description
ft_lstnew	Creates a new node with a given content.
ft_lstadd_front	Adds a new node at the beginning of a list.
ft_lstsize	Counts the number of nodes in a list.
ft_lstlast	Returns the last node in a list.
ft_lstadd_back	Adds a new node at the end of a list.
ft_lstdelone	Deletes a node and frees its content.
ft_lstclear	Deletes and frees a list and its contents.
ft_lstiter	Iterates through a list, applying a function to each node's content.
ft_lstmap	Creates a new list by applying a function to each node's content.

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Usage

Include the Library

To use Libft, include its header file in your C program:

#include "libft.h"

Example Usage

To demonstrate how to use some of the functions implemented in Libft, you can write a simple program like the following:

#include "libft.h"
#include <stdio.h>

int main(void)
{
    // Example: Using ft_strlen to find the length of a string
    char *str = "Hello, Libft!";
    size_t length = ft_strlen(str);
    printf("Length of string: %zu\n", length);

    // Example: Creating a linked list node using ft_lstnew
    t_list *node = ft_lstnew("Node content");
    if (node)
        printf("Node content: %s\n", (char *)node->content);

    return 0;
}

Compile and run this program with:

gcc -o test_program test_program.c -L. -lft
./test_program

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Compilation

To build the Libft library, follow these steps:

1. Run the make command in the project directory:

   make

2. This will create a static library file named libft.a.

3. To clean up the object files, use:

   make clean

4. To remove all compiled files, including libft.a, use:

   make fclean

5. To recompile everything from scratch, use:

   make re

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Integration

To integrate Libft into your project:

1. Include the libft.h header file in your source files:

   #include "libft.h"

2. Link the libft.a static library during compilation:

   gcc -o your_program your_program.c -L. -lft

3. Ensure the libft.a file is in the same directory or adjust the -L path accordingly.

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Testing

You can write your own test files to verify the behavior of the library functions. For example:

#include "libft.h"
#include <stdio.h>

int main(void)
{
    // Testing ft_atoi
    char *num_str = "42";
    int num = ft_atoi(num_str);
    printf("String '%s' converted to integer: %d\n", num_str, num);

    // Testing ft_memset
    char buffer[10];
    ft_memset(buffer, 'A', sizeof(buffer) - 1);
    buffer[9] = '\0';
    printf("Buffer after memset: %s\n", buffer);

    return 0;
}

Compile and run this file as described in the Compilation section.

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License

This project is part of the 42 curriculum and is intended for educational purposes. You are free to use, modify, and share the code for learning and personal projects. Attribution to the author is appreciated but not required.

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Happy coding! 🚀