get_next_line

Overview

get_next_line is a project from the 42 Network curriculum designed to implement a function that reads one line at a time from a file descriptor (fd). This function handles edge cases and adheres to specific requirements, ensuring it works seamlessly for both files and standard input.

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Function Prototype

char *get_next_line(int fd);

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Project Structure

File	Description
get_next_line.c	Contains the main get_next_line logic.
get_next_line_utils.c	Contains helper functions for get_next_line.
get_next_line.h	Header file with function prototypes and macros.

For Bonus Part:

File	Description
get_next_line_bonus.c	Handles multiple file descriptors (fd).
get_next_line_utils_bonus.c	Helper functions for the bonus implementation.
get_next_line_bonus.h	Header file for the bonus implementation.

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Features

1. Line Reading:

   • Reads a single line from a given file descriptor.
   • The line includes the newline (\n) character, if present.
   • Returns NULL if the end of the file is reached or an error occurs.

2. Dynamic Buffer Size:

   • The buffer size is defined during compilation using the BUFFER_SIZE macro.
   • Supports varying buffer sizes to optimize performance.

3. Static Variable:

   • Efficiently manages leftover data between function calls.

4. File Descriptor Management (Bonus):

   • Can handle multiple file descriptors simultaneously without losing context.

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Usage

Compilation

Compile the mandatory files:

cc -Wall -Wextra -Werror -D BUFFER_SIZE=42 get_next_line.c get_next_line_utils.c -o gnl

For the bonus part:

cc -Wall -Wextra -Werror -D BUFFER_SIZE=42 get_next_line_bonus.c get_next_line_utils_bonus.c -o gnl_bonus

Function Behavior

• Call get_next_line(fd) repeatedly to read one line at a time from the file descriptor.
• The function continues until the end of the file is reached or an error occurs.

Example Usage

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

int main() {
    int fd = open("file.txt", O_RDONLY);
    char *line;

    if (fd < 0)
        return (1);

    while ((line = get_next_line(fd)) != NULL) {
        printf("%s", line);
        free(line);
    }
    close(fd);
    return (0);
}

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Bonus Implementation

Requirements:

• Manage multiple file descriptors independently.
• Use a single static variable.

Example Bonus Usage:

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

int main() {
    int fd1 = open("file1.txt", O_RDONLY);
    int fd2 = open("file2.txt", O_RDONLY);
    char *line1, *line2;

    if (fd1 < 0 || fd2 < 0)
        return (1);

    line1 = get_next_line(fd1);
    line2 = get_next_line(fd2);

    printf("File 1: %s", line1);
    printf("File 2: %s", line2);

    free(line1);
    free(line2);
    close(fd1);
    close(fd2);
    return (0);
}