https://github.com/ygor-sena/42cursus-get-next-line
The second project of 42 curriculum asks students to implement a function that returns a line read from one or more file descriptors.
https://github.com/ygor-sena/42cursus-get-next-line
42 42-get-next-line 42cursus 42saopaulo 42school 42sp ansi-c c ecole42
Last synced: about 2 months ago
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The second project of 42 curriculum asks students to implement a function that returns a line read from one or more file descriptors.
- Host: GitHub
- URL: https://github.com/ygor-sena/42cursus-get-next-line
- Owner: ygor-sena
- License: gpl-3.0
- Created: 2022-06-29T14:21:04.000Z (almost 3 years ago)
- Default Branch: main
- Last Pushed: 2023-07-05T17:57:05.000Z (almost 2 years ago)
- Last Synced: 2025-02-24T06:17:37.015Z (2 months ago)
- Topics: 42, 42-get-next-line, 42cursus, 42saopaulo, 42school, 42sp, ansi-c, c, ecole42
- Language: C
- Homepage:
- Size: 39.1 KB
- Stars: 2
- Watchers: 1
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
## 📣 About the project
_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**.
## 📈 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 last one because it was an opportunity to see how linked list are used.
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. It reads a line, saves the content and joins the line when it matches an `EOF` (end of file) or `'\n'` (new line break);
- `read_line()`: reads a line at a max length of _BUFFER_SIZE_, which is defined at compilation time. If _BUFFER_SIZE_ is not defined, the program sets the standard buffer value to 1024;
- `is_new_line()`: checks whether the chunk read is a new line (i. e., it has `\n`) or not. It returns one if true and zero if false;
- `create_line()`: creates a line by joining read buffer sized chunks of a line until `EOF` or `\n` is encountered;
- `refactor_line()`: 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 and singly linked lists.
## ⚒️ 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= .c
```
Where _\_ 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 1024 as standard value for the buffer size.
To reference the `get_next_line()` function inside your project, don't forget to add the header:
```c
#include "get_next_line.h"
```
If you want to use the mandatory project, that is. If you want to use the bonus project to read multiple file descriptors, add the header:
```c
#include "get_next_line_bonus.h"
```
## 📖 References
- [Acelera GNL](https://rodsmade.notion.site/Acelera-Get_next_line-4902aab835ef4b86a7c55d82cc5c19ec) by [rodsmade](https://github.com/rodsmade).
- To test the project and check for memory leaks, I used the [gnlTester](https://github.com/Tripouille/gnlTester), made by [jgambard](https://github.com/Tripouille).