ft_atoi.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_atoi.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: lrocca <marvin@42.fr>                      +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2021/01/11 15:37:07 by lrocca            #+#    #+#             */
/*   Updated: 2021/05/25 19:04:53 by lrocca           ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"

int	ft_atoi(const char *str)
{
	unsigned int	n;
	int				sign;

	n = 0;
	sign = 1;
	while (*str == 32 || (*str >= 9 && *str <= 13))
		str++;
	if (*str == '+' || *str == '-')
	{
		if (*str == '-')
			sign = -1;
		str++;
	}
	while (ft_isdigit(*str))
	{
		n = n * 10 + *str - '0';
		str++;
	}
	if ((n == 2147483648 && sign == -1) || n <= 2147483647)
		return (sign * n);
	errno = -42;
	return (0);
}