This project has been created as part of the 42 curriculum by .

Libft

Description

Libft is a custom C library. Its purpose is to reimplement essential standard C library functions, extend them with additional utility functions, and introduce a basic implementation of linked lists.

• low-level memory management
• string manipulation
• dynamic allocation
• pointer arithmetic
• linked list data structures
• code organization and modularity
• Makefile usage and static library creation

The final result is the library "libft.a".

Instructions

To compile the library, you must provide a "Makefile" that produces "libft.a" using:

-Wall -Wextra -Werror

Makefile rules: -NAME -> of the target file -all -> to create use the command "make all" -clean -> remove objects files with the command "make clean" -fclean -> remove objects files and archive file with the command "make fclean" -re -> recreate the files using the commands "fclean + all" -ar rcs libft.a *.o -> to create the libft.a file

Resources

Manual pages man 3 memset, man 3 memcpy, man 3 calloc,
man 3 strdup, man 3 strlcpy, man 3 strlcat

Memory management references

• Understanding malloc, free, and dynamic allocation
• Articles about pointer safety and memory leaks

String manipulation references

• Documentation on C strings and buffer handling

Linked list references

• Guides explaining node structures, pointer traversal, and list operations

Use of AI

AI was used to: -Help with the structuring of this README -Debug memory-related functions such as "ft_split", "ft_strdup", and other functions
-Understanding concepts: linked lists, structures, and nodes

Functions Overview

PART 1 — Standard C Library Functions

Character checks

• ft_isalpha – checks if a character is alphabetical
• ft_isdigit – checks if a character is a digit
• ft_isalnum – checks if a character is alphanumeric
• ft_isascii – checks if a character is a valid ASCII character
• ft_isprint – checks if a character is printable

Character conversion

• ft_toupper – converts a character to uppercase
• ft_tolower – converts a character to lowercase

Memory functions

• ft_memset – fills bytes in memory with a constant value
• ft_bzero – writes zeroes to a memory area
• ft_memcpy – copies memory from source to destination
• ft_memmove – safely copies overlapping memory areas
• ft_memchr – locates a byte in memory
• ft_memcmp – compares two memory areas

String functions

• ft_strlen – returns the length of a string
• ft_strlcpy – copies a string with size limitation
• ft_strlcat – concatenates strings with size limitation
• ft_strchr – locates a character in a string
• ft_strrchr – locates the last occurrence of a character
• ft_strncmp – compares two strings
• ft_strnstr – locates a substring within a string
• ft_strdup – duplicates a string (uses malloc)

Conversion

• ft_atoi – converts a string to an integer

Memory allocation

• ft_calloc – allocates memory and sets it to zero

PART 2 — Additional Functions

String manipulation

• ft_substr – extracts a substring
• ft_strjoin – concatenates two strings
• ft_strtrim – trims characters from both ends of a string
• ft_split – splits a string into an array of substrings
• ft_itoa – converts an integer into a string
• ft_strmapi – applies a function to each character of a string
• ft_striteri – applies a function to each character of a string (in place)

Output functions

• ft_putchar_fd – outputs a character to a file descriptor
• ft_putstr_fd – outputs a string to a file descriptor
• ft_putendl_fd – outputs a string followed by a newline
• ft_putnbr_fd – outputs an integer to a file descriptor

PART 3 — Linked List Functions

All linked list functions operate on the t_list structure:

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

List creation and manipulation

• ft_lstnew – creates a new list node
• ft_lstadd_front – adds a node to the beginning of the list
• ft_lstadd_back – adds a node to the end of the list
• ft_lstsize – returns the number of nodes in the list
• ft_lstlast – returns the last node of the list

List deletion and cleanup

• ft_lstdelone – deletes a single node using a function
• ft_lstclear – deletes all nodes and frees memory
• ft_lstiter – applies a function to each node's content

List mapping

• ft_lstmap – creates a new list by applying a function to each node's content