get_next_line.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   get_next_line.c                                    :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: scosta-j <scosta-j@student.42.fr>          +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2023/02/10 22:32:57 by scosta-j          #+#    #+#             */
/*   Updated: 2023/02/17 22:56:46 by scosta-j         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

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

/**
 * BUFFER_SIZE + 1 para o /0 e /n ? confirmar
 * //exceptions buffersize<0 && that condition from read if the file exists
 * check if the buffer has something already 
*/
char	*get_next_line(int fd)
{
	static char	buffer[BUFFER_SIZE + 1];
	char		*line;
	int			i;

	i = 0;
	if (read(fd, 0, 0) < 0 || BUFFER_SIZE <= 0)
	{
		while (buffer[i])
		{
			buffer[i] = 0;
			i++;
		}
		return (NULL);
	}
	line = NULL;
	while (buffer[0] || read(fd, buffer, BUFFER_SIZE) > 0)
	{
		line = ft_strjoin(line, buffer);
		if (update_buffer(buffer))
			break ;
	}
	return (line);
}

// char	*treat_buffer_newline(char *buffer, char *line)
// {
// 	int	i;
// 	int	j;

// 	i = 0;
// 	j = 0;
// 	while (buffer[i])
// 	{
// 		if (i <= find_chr_index(buffer, 10))
// 			line[i] = buffer[i];
// 		else
// 		{
// 			buffer[j] = buffer[i];
// 			j++;
// 		}
// 		i++;
// 	}
// 	while (buffer[j])
// 	{
// 			buffer[j] = 0;
// 			j++;
// 	}
// 	line[i] = '\0';
// 	return (line);
// }

// /**
//  * this function reads the file until it reaches the end of it
//  * or it reaches a new line character
// */
// char	*read_line(int fd, char *buffer, char *line)
// {
// 	int	nchr_read;
// 	int	nline_flag;

// 	nchr_read = 0;
// 	nline_flag = 0;
// 	while (1)
// 	{
// 		nchr_read = read (fd, buffer, BUFFER_SIZE);
// 		buffer[nchr_read] = '\0';
// 		if (nchr_read == 0)
// 			return (line);
// 		nline_flag = find_chr_index(buffer, 10);
// 		if (nline_flag == -1)
// 			line = update_line(buffer, line, BUFFER_SIZE);
// 		else
// 			return (update_line(buffer, line, nline_flag));
// 	}
// }

/**
 * this function returns the index of the char
 * @param str its the string where the possible char might be 
 * @param c its the char that we are searching in the string 
 * but there is an exception if we want to find the '\0' the function will
 * return the string lenght
 * @returns the index where char was found or -1 if the chr isn't found
*/
int	find_chr_index(char *str)
{
	int	i;

	i = 0;
	if (!str)
		return (0);
	while (str[i] && str[i] != '\n')
		i++;
	if (str[i] == '\n')
		i++;
	return (i);
}

/**
 * with the help of the auxiliar index size the function updates the
 * array that is going to be printed until the new line 
 * and after that cleans the static buffer erasing the new line and
 * everthing that is before that 
 * @param size the index that marks the end of the buffer 
 * that is going to be copied to line 
 * and after that point what is going to be kept after cleaning the buffer
*/
int	update_buffer(char *buffer)
{
	int	i;
	int	j;
	int	new_line;

	i = 0;
	j = 0;
	new_line = 0;
	while (buffer[i])
	{
		if (new_line)
			buffer[j++] = buffer[i];
		if (buffer[i] == '\n')
			new_line = 1;
		buffer[i++] = 0;
	}
	return (new_line);
}

/**
 * @pre s1 must be dynamically allocated because its going to be free'd
 * acts like the realloc function but for strings returns a concatenated string 
 * @param s1 string thats going to be concatented as the suffix
 * @param s2 string thats going to be concatented as the preffix
 * @param size refers to the size of the s2 string thats going to be concatenated
*/
char	*ft_strjoin(char *s1, char *s2)
{
	int		i;
	int		strindex;
	char	*str;

	i = 0;
	strindex = 0;
	str = malloc(find_chr_index(s1) + find_chr_index(s2) + 1);
	if (!str)
		return (0);
	while (s1 && s1[i])
		str[strindex++] = s1[i++];
	free (s1);
	i = 0;
	while (*s2)
	{
		str[strindex++] = *s2;
		if (*s2++ == '\n')
			break ;
	}
	str[strindex] = '\0';
	return (str);
}

int	main(void)
{
	int		fd;
	char	*line;

	fd = open("text1.txt", O_RDONLY);
	line = get_next_line(fd);
	printf("line 1: %s \n", line);
	free(line);
		line = get_next_line(fd);
	printf("line 2: %s \n", line);
	free(line);
		line = get_next_line(fd);
	printf("line 3: %s \n", line);
	free(line);
		line = get_next_line(fd);
	printf("line 4: %s \n", line);
	free(line);
		line = get_next_line(fd);
	printf("line 5: %s \n", line);
	free(line);
}

// int main(void)
// {
// 	static	char str[6] = "abc\nd";
	
// 	printf("%d \n",find_chr_index(NULL));
// 	printf("%s" , ft_strjoin(NULL, "Abc\nD"));
// 	printf("%d :number new line :string %s", update_buffer(str), str);
// 	return (0);
// }