ft_atoi.c

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/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_atoi.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: tspoof <tspoof@student.hive.fi>            +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2022/11/02 14:03:13 by tspoof            #+#    #+#             */
/*   Updated: 2022/11/30 16:45:21 by tspoof           ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */
 
#include "libft.h"
 
int ft_atoi(const char *str)
{
    int             i;
    int             sign;
    unsigned long   val;
 
    sign = 1;
    val = 0;
    i = 0;
    while ((str[i] >= 9 && str[i] <= 13) || str[i] == 32)
        i++;
    if (str[i] == '-')
        sign = -1;
    if (str[i] == '-' || str[i] == '+')
        i++;
    while (str[i] >= '0' && str[i] <= '9' && str[i] != '\n')
    {
        val = val * 10 + (str[i] - '0');
        if (sign == 1 && val > 9223372036854775807)
            return (-1);
        if (sign == -1 && val > 9223372036854775807)
            return (0);
        i++;
    }
    return ((int)(sign * val));
}