ft_atoi.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_atoi.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: wbertoni <marvin@42.fr>                    +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2020/01/30 11:44:13 by wbertoni          #+#    #+#             */
/*   Updated: 2020/02/07 13:44:31 by wbertoni         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"

int	ft_atoi(const char *str)
{
	unsigned long long int	nbr;
	int						index;
	int						sign;

	nbr = 0;
	sign = 1;
	index = 0;
	while (ft_isspace(str[index]))
		index++;
	if (str[index] == '-' || str[index] == '+')
	{
		sign = (str[index] == '-') ? -1 : 1;
		index++;
	}
	while (ft_isdigit(str[index]))
	{
		nbr *= 10;
		nbr += str[index++] - '0';
	}
	if (nbr > (unsigned long long int)LONG_MAX && sign == 1)
		return (-1);
	if (nbr > (unsigned long long int)(-LONG_MIN) && sign == -1)
		return (0);
	return ((int)(nbr * sign));
}