/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   ft_atoi.c                                          :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: thrieg <thrieg@student.42mulhouse.fr>      +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2024/10/14 18:37:49 by thrieg            #+#    #+#             */
/*   Updated: 2025/02/16 19:02:53 by thrieg           ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"
#include <errno.h>

static int	ft_is_space(char c)
{
	if (c == '\t' || c == '\n' || c == '\v'
		|| c == '\f' || c == '\r' || c == ' ')
		return (1);
	else
		return (0);
}

static int	ft_convert_to_int(const char *str, int sign, int *overflow_flag)
{
	int	value;

	value = 0;
	while (ft_isdigit(*str))
	{
		if (sign == 1)
		{
			if (value > (INT_MAX - (*str - '0')) / 10)
				if (overflow_flag)
					*overflow_flag = 1;
			value = value * 10 + (*str - '0');
		}
		else
		{
			if (value < (INT_MIN + (*str - '0')) / 10)
				if (overflow_flag)
					*overflow_flag = 1;
			value = value * 10 - (*str - '0');
		}
		str++;
	}
	return (value);
}

int	ft_atoi(const char *nptr, int *overflow_flag)
{
	int	sign;

	if (overflow_flag)
		*overflow_flag = 0;
	while ((*nptr != '\0') && ft_is_space(*nptr))
	{
		nptr++;
	}
	sign = 1;
	if ((*nptr != '\0') && (*nptr == '-' || *nptr == '+'))
	{
		if (*nptr == '-')
			sign = -sign;
		nptr++;
	}
	if (!ft_isdigit(*nptr))
		return (0);
	return (ft_convert_to_int(nptr, sign, overflow_flag));
}