mouadd55/Get_next_line-42Cursus

Get_next_line

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💡 About the project

The aim of this project is to make you code a function that returns a line, read from a file descriptor.

Because reading a line from a fd is way too tedious, this project is about creating your own function that returns a line read from one file descriptor or more, if you consider the bonus project requirement. The function get_next_line() returns NULL, if there is nothing else to read or if an error occurred. It should work as expected both when reading a file and when reading from the standard output.

The main objetive of this project is to make students learn about static variables.

For more detailed information, look at the subject of this project.

How it was implemented

There are many ways to solve the problem stated. Either using an array or a singly linked list as a data structure. I decided to implement the first one.

The project contains six files. The ones that ends with _bonus are the bonus project that reads a line from two or more file descriptors at the same time. To sum up,

• get_next_line.h: contains the prototypes of all necessary functions to the project.
• get_next_line.c: it has five functions. They are:
  • get_next_line(): it's the project main function.
  • read_line(): reads a line at a max length of BUFFER_SIZE which is defined at compilation time and creates a line by joining read buffer sized chunks of a line until EOF or \n is encountered. If BUFFER_SIZE is not defined, the program sets the standard buffer value to 5;
  • ft_substr(): takes the full line which contains the '\n' and create a substring from the beginning of the line until the '\n' ('\n' is included in the substring) and returns a clean line.
  • save_rest(): if a buffer sized chunk has \n, the function will save the content after \n to create the next line of the file descriptor by the time the get_next_line() function is called again. That's the reason why we need a static variable, the information isn't lost by the time the function ends.
• get_next_line_utils.c: implements helper functions to manipulate heap(or dynamic) memory.

How to use the project

To use the get_next_line() in your project it's necessary to include the three files mentioned above to be compiled, either the mandatory or the bonus files, and be sure to include the following flags:

$> gcc -Wall -Wextra -Werror -D BUFFER_SIZE=<length> <files>.c

Where <length> can be substituted by the number of bytes read at a time into the buffer for the read function. If BUFFER_SIZE is not defined, it will be defined to 5 as standard value for the buffer size.

To reference the get_next_line() function inside your project, don't forget to add the header:

#include "get_next_line.h"