libft

Reimplementation of a simplified C standard library for the 42 curriculum.
This project provides custom implementations of many libc functions, additional string/memory utilities, and a full linked list API.

Project developed at 42 Telefónica by Diego Valladares Ortega.

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🧩 Overview

libft is a static C library containing reusable low-level functions that are commonly needed in future projects. It includes:

• Character checks (ft_isalpha, ft_isdigit, …)
• Memory manipulation (ft_memset, ft_memcpy, ft_calloc, …)
• String handling (ft_strlen, ft_strlcpy, ft_split, …)
• Conversions (ft_atoi, ft_itoa)
• File descriptor helpers (ft_put* functions)
• A complete linked list implementation (t_list and operations)

The purpose is to avoid rewriting basic utilities in future projects and gain a deeper understanding of how standard library functions work internally.

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📁 Project Structure

src/        # All ft_*.c files (implementations)
include/    # Public header: libft.h
tests/      # Optional test files (not part of 42 requirement)
Makefile    # Builds the static library

🔧 Build Instructions

Clone the repository:

git clone https://github.com/<TU_USUARIO>/libft.git
cd libft

Build the library:

make

This will generate:

./libft.a

Clean object files:

make clean

Remove objects + library:

make fclean

Recompile everything:

make re

🧪 Testing (Optional) A simple test file is included in:

tests/main.c

Compile and run:

cc tests/main.c -L. -lft -Iinclude -o test_libft
./test_libft

You can add your own test cases to validate more functions.

📚 Implemented Functions Part 1 – Libc Functions ft_isalpha

ft_isdigit

ft_isalnum

ft_isascii

ft_isprint

ft_strlen

ft_memset

ft_bzero

ft_memcpy

ft_memmove

ft_strlcpy

ft_strlcat

ft_toupper

ft_tolower

ft_strchr

ft_strrchr

ft_strncmp

ft_memchr

ft_memcmp

ft_strnstr

ft_atoi

ft_calloc

ft_strdup

Part 2 – Additional Functions

ft_substr

ft_strjoin

ft_strtrim

ft_split

ft_itoa

ft_strmapi

ft_striteri

ft_putchar_fd

ft_putstr_fd

ft_putendl_fd

ft_putnbr_fd

Bonus – Linked List Functions

Using the structure:

typedef struct s_list
{
    void            *content;
    struct s_list   *next;
} t_list;

Implemented:

ft_lstnew

ft_lstadd_front

ft_lstsize

ft_lstlast

ft_lstadd_back

ft_lstdelone

ft_lstclear

ft_lstiter

ft_lstmap

🧠 What I Learned

Inner workings of common libc functions

Memory allocation and manual management

Handling strings and pointers safely

Static library creation (ar)

Data structures: singly linked lists

Writing clean, reusable C code following 42 Norm

📄 License

This project is licensed under the MIT License.
See the LICENSE file for more details.