Libft

A custom implementation of essential C standard library functions, created as part of the curriculum at Codam (42 Amsterdam).

About

Libft is the first project at 42, where students recreate their own library of standard C functions. This library serves as a foundation for future projects throughout the 42 curriculum, providing essential tools for string manipulation, memory management, and more.

This extended version of Libft includes:

• Standard C Library Functions - Core functions for string, memory, and character operations
• Additional Utility Functions - Enhanced string manipulation and output functions
• ft_printf - Custom implementation of formatted output functions
• get_next_line - Line reading functionality for file descriptors

Project Information

• Author: rmengelb
• School: Codam (42 Amsterdam)
• Cohort: 2024
• Project: Libft

Functions

Part 1 - Libc Functions

These functions replicate the behavior of standard C library functions:

Character Checks & Conversions:

• ft_isalpha - checks for alphabetic character
• ft_isdigit - checks for digit character
• ft_isalnum - checks for alphanumeric character
• ft_isascii - checks for ASCII character
• ft_isprint - checks for printable character
• ft_toupper - converts character to uppercase
• ft_tolower - converts character to lowercase

String Functions:

• ft_strlen - calculates string length
• ft_strlcpy - size-bounded string copying
• ft_strlcat - size-bounded string concatenation
• ft_strchr - locates first occurrence of character in string
• ft_strrchr - locates last occurrence of character in string
• ft_strncmp - compares two strings up to n characters
• ft_strnstr - locates substring in string
• ft_strdup - duplicates a string

Memory Functions:

• ft_memset - fills memory with a constant byte
• ft_bzero - zeros a byte string
• ft_memcpy - copies memory area
• ft_memmove - copies memory area (handles overlap)
• ft_memchr - scans memory for a character
• ft_memcmp - compares memory areas

Conversion:

• ft_atoi - converts string to integer (returns long int)

Memory Allocation:

• ft_calloc - allocates and zeros memory

Part 2 - Additional Functions

Additional useful functions not in the standard library:

• ft_substr - extracts substring from string
• ft_strjoin - concatenates two strings
• ft_strjoin_array - joins array of strings with separator
• ft_strtrim - trims characters from beginning and end of string
• ft_split - splits string into array of strings by delimiter
• ft_itoa - converts integer to string
• ft_strmapi - applies function to each character of string
• ft_striteri - applies function to each character of string with index
• ft_putchar_fd - outputs character to file descriptor
• ft_putstr_fd - outputs string to file descriptor
• ft_putendl_fd - outputs string to file descriptor with newline
• ft_putnbr_fd - outputs integer to file descriptor

ft_printf

Custom implementation of printf with formatted output:

• ft_printf - outputs formatted string to stdout
• ft_dprintf - outputs formatted string to specified file descriptor

Supported format specifiers:

• %c - character
• %s - string
• %p - pointer address
• %d - decimal integer
• %i - integer
• %u - unsigned integer
• %x - hexadecimal (lowercase)
• %X - hexadecimal (uppercase)
• %% - percent sign
• %r - reverse string (custom specifier)

get_next_line

Reads a line from a file descriptor:

• get_next_line - reads and returns the next line from a file descriptor, including the newline character

Compilation

The library includes a Makefile with the following rules:

make        # Compiles the library (libft.a)
make clean  # Removes object files
make fclean # Removes object files and library
make re     # Recompiles the library

The compiled library (libft.a) includes all standard libft functions, ft_printf, and get_next_line.

Usage

1. Clone the repository:

git clone <repository-url> libft
cd libft

2. Compile the library:

make

3. Include in your project:

#include "libft.h"

4. Compile your project with the library:

gcc -Wall -Wextra -Werror your_file.c -L. -lft -o your_program

Project Structure

libft/
├── Makefile
├── README.md
├── libft.h
├── ft_*.c              # Standard libft functions
├── printf/
│   ├── ft_printf.c
│   └── ft_print_*.c    # Format specifier implementations
└── gnl/
    ├── ft_gnl.c
    └── ft_gnl_helpers.c

Norms

This project adheres to the 42 Norm, which includes:

• Maximum 25 lines per function
• Maximum 5 functions per file
• Forbidden: for, do-while, switch, case, goto
• All variables must be declared at the beginning of the function
• No more than 4 parameters per function

Testing

It's recommended to test your library with various testers available in the 42 community:

• Libft Unit Tests
• Libftest
• war-machine

Resources

• 42 Norm Documentation
• C Library Reference

License

This project is part of the 42 curriculum and is intended for educational purposes.

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Made with ☕ at Codam (42 Amsterdam) - 2024