base struct

lib/libft/srcs/format/ft_atoi.c

@@ -0,0 +1,72 @@
+/* ************************************************************************** */
+/*                                                                            */
+/*                                                        :::      ::::::::   */
+/*   ft_atoi.c                                          :+:      :+:    :+:   */
+/*                                                    +:+ +:+         +:+     */
+/*   By: nalebrun <nalebrun@student.s19.be>         +#+  +:+       +#+        */
+/*                                                +#+#+#+#+#+   +#+           */
+/*   Created: 2024/10/14 14:00:41 by nalebrun          #+#    #+#             */
+/*   Updated: 2024/11/27 12:59:01 by nalebrun         ###   ########.fr       */
+/*                                                                            */
+/* ************************************************************************** */
+
+#include "../../libft.h"
+
+static int	ft_isspace(char c)
+{
+	if (c == ' ' || c == '\t' || c == '\n' || c == '\v' || c == '\f'
+		|| c == '\r')
+		return (1);
+	else
+		return (0);
+}
+
+static int	ft_signer(char c, int *i)
+{
+	int	sign;
+
+	sign = 1;
+	if (c == '-')
+	{
+		sign *= -1;
+		(*i)++;
+	}
+	else if (c == '+')
+		(*i)++;
+	return (sign);
+}
+
+static int	ft_signed(int sign)
+{
+	if (sign == -1)
+		return (0);
+	else
+		return (-1);
+}
+
+int	ft_atoi(const char *str)
+{
+	int		i;
+	int		sign;
+	long	res;
+	int		current_digit;
+
+	if (!str)
+		return (-1);
+	res = 0;
+	i = 0;
+	while (ft_isspace(str[i]))
+		i++;
+	sign = ft_signer(str[i], &i);
+	while (str[i] == '0')
+		i++;
+	while (ft_isdigit(str[i]))
+	{
+		current_digit = str[i] - '0';
+		if (res > (LONG_MAX - current_digit) / 10)
+			return (ft_signed(sign));
+		res = (res * 10) + current_digit;
+		i++;
+	}
+	return ((int)(res *= sign));
+}