Get Next Line

A function that reads content line by line from a file descriptor, one line at a time.

Description

Get Next Line is a project that teaches you how to read from a file descriptor and return one line at a time, efficiently managing memory and handling various edge cases. This function is useful for reading large files without loading the entire content into memory.

Features

• Reads one line at a time from any file descriptor
• Efficient buffer management
• Handles multiple file descriptors simultaneously
• Memory leak protection
• Works with files, standard input, and pipes

Function Prototype

int get_next_line(int fd, char **line);

Return Values

• 1: A line was read
• 0: EOF reached
• -1: An error occurred

Compilation

gcc -Wall -Wextra -Werror -D BUFFER_SIZE=42 get_next_line.c get_next_line_utils.c

Usage

1. Clone the repository:

git clone https://github.com/bratzwitch/get_next_line.git
cd get_next_line

2. Include in your project:

#include "get_next_line.h"

3. Compile with your program:

gcc -Wall -Wextra -Werror -D BUFFER_SIZE=1024 your_file.c get_next_line.c get_next_line_utils.c

Example Usage

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

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

    if (argc != 2)
        return (1);
    
    fd = open(argv[1], O_RDONLY);
    if (fd == -1)
        return (1);
    
    while ((ret = get_next_line(fd, &line)) > 0)
    {
        printf("%s\n", line);
        free(line);
    }
    
    if (ret == 0)
        printf("%s\n", line);
    free(line);
    close(fd);
    
    return (0);
}

Buffer Size

The buffer size can be modified during compilation using the -D BUFFER_SIZE=n flag. Different buffer sizes will affect performance:

• Small buffer (1): More system calls, slower
• Large buffer (1000000): Less system calls, more memory usage
• Optimal buffer (1024-8192): Good balance

Files

• get_next_line.c: Main function implementation
• get_next_line_utils.c: Helper functions
• get_next_line.h: Header file with prototypes and includes

Requirements

• Must work with any file descriptor
• Must handle multiple file descriptors
• Must not lose data between calls
• Memory must be properly managed (no leaks)

Author

Viacheslav Moroz - 42 Student