From 1d032f7b5e10132abdd29f231241016b6a7d27d7 Mon Sep 17 00:00:00 2001
From: Timo Schmidt <tischmid@student.42berlin.de>
Date: Fri, 31 Mar 2023 22:05:56 +0200
Subject: [PATCH] Implemented ft_atoi.c

---
 ex03/ft_atoi.c | 80 +++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 70 insertions(+), 10 deletions(-)

diff --git a/ex03/ft_atoi.c b/ex03/ft_atoi.c
index c64657a..2e5ff51 100644
--- a/ex03/ft_atoi.c
+++ b/ex03/ft_atoi.c
@@ -6,25 +6,85 @@
 /*   By: tischmid <marvin@42.fr>                    +#+  +:+       +#+        */
 /*                                                +#+#+#+#+#+   +#+           */
 /*   Created: 2023/03/27 19:51:48 by tischmid          #+#    #+#             */
-/*   Updated: 2023/03/28 14:39:34 by tischmid         ###   ########.fr       */
+/*   Updated: 2023/03/31 21:58:42 by tischmid         ###   ########.fr       */
 /*                                                                            */
 /* ************************************************************************** */
 
-int	ft_isspace(char c)
+unsigned int	char_count(const char *str, char c)
 {
-	return (c == ' '
-		|| c == '\t'
-		|| c == '\n'
-		|| c == '\r'
-		|| c == '\f'
-		|| c == '\v');
+	unsigned int	count;
+
+	count = 0;
+	while (*str)
+	{
+		if (*str == c)
+			++count;
+		++str;
+	}
+	return (count);
+}
+
+// Return 0 if the base is invalid or the length of the base otherwise
+unsigned int	is_valid_base(const char *base)
+{
+	unsigned int	size;
+
+	size = 0;
+	while (*base)
+	{
+		if (*base == '+' || *base == '-' || *base == ' ')
+			return (0);
+		if (char_count(base, *base) > 1)
+			return (0);
+		++size;
+		++base;
+	}
+	if (size < 2)
+		return (0);
+	return (size);
+}
+
+int	char_index(const char *str, const char c)
+{
+	int	idx;
+
+	idx = 0;
+	while (*str)
+	{
+		if (*str++ == c)
+			return (idx);
+		++idx;
+	}
+	return (-1);
 }
 
 int	ft_atoi(char *str)
 {
-	while (ft_isspace(*str))
+	int				sign;
+	int				abs;
+	int				index_in_base;
+	unsigned int	base_len;
+
+	abs = 0;
+	sign = 1;
+	base_len = is_valid_base("0123456789");
+	if (!base_len)
+		return (0);
+	while (*str == ' ' || *str == '\t'
+		|| *str == '\n' || *str == '\r'
+		|| *str == '\f' || *str == '\v')
 		++str;
-	return (0);
+	while (*str == '+' || *str == '-')
+		if (*str++ == '-')
+			sign *= -1;
+	index_in_base = char_index("0123456789", *str);
+	while (index_in_base >= 0)
+	{
+		abs = abs * base_len + index_in_base;
+		++str;
+		index_in_base = char_index("0123456789", *str);
+	}
+	return (sign * abs);
 }
 
 /* ////