get_next_line/get_next_line.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   get_next_line.c                                    :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: kcolin <marvin@42.fr>                      +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2024/10/23 20:32:46 by kcolin            #+#    #+#             */
/*   Updated: 2024/10/24 12:34:49 by kcolin           ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "get_next_line.h"
#include <stdlib.h>

static char	*ft_realloc(char *ptr, size_t new_size, size_t old_size)
{
	char	*outptr;
	size_t	i;

	outptr = malloc(new_size);
	if (outptr != NULL)
	{
		i = 0;
		while (i < old_size)
		{
			outptr[i] = ptr[i];
			i++;
		}
	}
	free(ptr);
	return (outptr);
}

static char	*ft_strchr(const char *s, int c)
{
	int	i;

	i = 0;
	while (s[i] != '\0')
	{
		if (s[i] == (char)c)
			return ((char *)s + i);
		i++;
	}
	if ((char)c == '\0')
		return ((char *)s + i);
	return (0);
}

char	*get_next_line(int fd)
{
	static char		*buffer = NULL;
	static size_t	buf_size = BUFFER_SIZE;
	static size_t	length = 0;
	int				num_bytes_read;
	char			*newline_addr;
	char			*out;
	long			i;

	if (buffer == NULL)
	{
		buffer = malloc(BUFFER_SIZE * sizeof(char));
		buf_size = BUFFER_SIZE;
		length = 0;
	}
	if (buffer == NULL)
		return (NULL);
	num_bytes_read = 1;
	while (num_bytes_read != 0)
	{
		if (length == buf_size)
		{
			buffer = ft_realloc(buffer, sizeof(char) * buf_size * 1.5, buf_size);
			if (buffer == NULL)
				return (NULL);
			buf_size *= 1.5;
		}
		num_bytes_read = read(fd, buffer + length, buf_size - length);
		if (num_bytes_read < 0)
		{
			free(buffer);
			buffer = NULL;
			return (NULL);
		}
		length += num_bytes_read;
		newline_addr = ft_strchr(buffer, '\n');
		if (newline_addr != NULL)
		{
			out = malloc((newline_addr - buffer + 1) * sizeof(char));
			out[(newline_addr - buffer)] = '\0';
			i = 0;
			while (i < (newline_addr - buffer))
			{
				out[i] = buffer[i];
				i++;
			}
			return (out);
		}
	}
	return (buffer);
}