Get_next_line

This project is about programming a function that returns a line read from a file descriptor.

💡 About the project

_This project introduces the concepts of static variables, dynamic memory allocation, file descriptors and macros while solving one simple task: that of using the Linux standard function read() to scan a file for single lines (i.e. strings of chars with a single trailing \n (new line character)).

📁 Files/src

get_next_line.c Function implementation.
- ft_found_error finds an error in input
- ft_free de-allocate the memory
- ft_slice slice the string into pieces
- ft_substr returns a substring from a string
get_next_line_utils.c Auxiliary functions (project requirement).
- ft_strlen calculate the length of a string
- ft_strchr locate character in string
- ft_strjoin concatenates two strings
- ft_strlcpy concatenate string to an specific size
- ft_strdup creates a dupplicate for the string passed as parameter
get_next_line.h Header file.
main.c Printing loop iterating over the file : calls get_next_line to fetch each line, then prints.
*_bonus.c The files is exact copies of corresponding files but with the challenge you can read from the file descriptors 3, 4 and 5, to doing able to read from a different fd per call without losing the reading thread of each file descriptor or returning a line from another.

🛠️ Usage

Requirements

This project requires GNU Compiler Collection and GNU Make compiler.
❗️| Make sure you have all the required tools installed on your local machine then continue with these steps.

Instructions

This function is not a stand-alone program, its files must be included and compiled within another project.

0. Download the archives

Download the archives and go to the folder directory:

# Clone the repository
$ git clone https://github.com/mewmewdevart/get_next_line

# Enter into the directory
$ cd get_next_line/src/

1. Using it in your code

To use the function in your code, simply include its header:

#include "get_next_line.h"

And create a main with some inserts.
Example main.c:

#include "get_next_line.h"
#include <stdio.h>
#include <fcntl.h>

int	main(int argc, char **argv)
{
	int		fd;
	char	*line;

	(void)argc;
	fd = open(argv[1], O_RDONLY);
	if (fd == -1)
	{
		printf("open() error\n");
		return (1);
	}
	line = "";
	while (line != NULL)
	{
		line = get_next_line(fd);
		printf("%s", line);
		free(line);
	}
	fd = close(fd);
	if (fd == -1)
	{
		printf("close() error\n");
		return (1);
	}
	printf("%d", fd);
	return (0);
}

2. Compilation

When compiling your code, add the source files and the required flag:

$ gcc get_next_line_utils.c get_next_line.c main.c -D BUFFER_SIZE=<size> -o get_next_line

Here BUFFER_SIZE determines the size of the buffer used to read the file (in other words, how manny chars shall be read at once with every read() call). To run the program, enter the following in the command prompt:

$ ./get_next_line [file.txt]

Output should show the entire contents of the given file followed by a newline \n.

📋 Credits

Developed with love 💜 by Larissa Cristina Benedito (Mewmew/Larcrist).