ft_atoi.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_atoi.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: aelphias <aelphias@student.42.fr>          +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2019/09/27 21:19:23 by aelphias          #+#    #+#             */
/*   Updated: 2019/10/21 16:12:05 by aelphias         ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"

int	ft_atoi(const char *str)
{
	long long	rs;
	int			negative;

	negative = 1;
	rs = 0;
	while (*str && (*str == ' ' || *str == '\n' || *str == '\t' ||
					*str == '\v' || *str == '\f' || *str == '\r'))
		++str;
	if (*str == '-')
		negative = -1;
	if (*str == '-' || *str == '+')
		++str;
	while (*str && *str >= '0' && *str <= '9')
	{
		rs = rs * 10 + (*str - 48);
		++str;
		if (rs < 0 && negative > 0)
			return (-1);
		if (rs < 0 && negative < 0)
			return (0);
	}
	return (rs * negative);
}