ft_atoi.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_atoi.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: smonroe <marvin@42.fr>                     +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2018/04/16 08:10:38 by smonroe           #+#    #+#             */
/*   Updated: 2019/04/16 21:10:28 by smonroe          ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"

int		ft_atoi(const char *str)
{
	int			i;
	int			l;
	long long	n;

	i = 0;
	n = 0;
	l = 0;
	while (str[i] == '\r' || str[i] == '\n' || str[i] == '\t' ||
			str[i] == '\f' || str[i] == '\v' || str[i] == ' ')
		i++;
	if (str[i] == '-' || str[i] == '+')
		l = i++;
	while (str[i] != '\0')
	{
		if (n >= 922337203685477580 && (((str[i] - '0') > 8 && str[l] == '-') ||
										((str[i] - '0') > 7 && str[l] != '-')))
			return (str[l] == '-' ? 0 : -1);
		if (str[i] >= '0' && str[i] <= '9')
			n = n * 10 + (str[i] - '0');
		else if (!(str[i] >= '0' && str[i] <= '9'))
			break ;
		i++;
	}
	return (str[l] == '-' ? (n * -1) : n);
}