1 files changed, 99 insertions, 0 deletions
diff --git a/utils.c b/utils.c
index 8b13789..9e8d4e9 100644
--- a/utils.c
+++ b/utils.c
@@ -1 +1,100 @@
+#include <stdlib.h>
+#include "header.h"
 
+#define MIN_INT (1 << 31)
+#define MAX_INT (~(1 << 31))
+
+static int	precheck(const char **str)
+{
+	int is_negative;
+
+	while (**str == ' ' || **str == '\t' || **str == '\n'
+			|| **str == '\v' || **str == '\f' || **str == '\r')
+		(*str)++;
+	is_negative = 0;
+	if (**str == '-' || **str == '+')
+	{
+		if (**str == '-')
+			is_negative = 1;
+		(*str)++;
+	}
+	return (is_negative);
+}
+
+int			ft_atoi(const char *str)
+{
+	unsigned int	nb;
+	int				i;
+	int				is_negative;
+
+	is_negative = precheck(&str);
+	i = 0;
+	nb = 0;
+	while (str[i] >= '0' && str[i] <= '9')
+	{
+		if (!is_negative && nb > (unsigned int)MAX_INT)
+			return (-1);
+		else if (nb > (unsigned int)MIN_INT)
+			return (0);
+		nb *= 10;
+		nb += str[i] - '0';
+		i++;
+	}
+	return ((int)(is_negative ? -nb : nb));
+}
+
+char	*ft_strndup(const char *s1, int n)
+{
+	char	*clone;
+	int	i;
+
+	if ((clone = (char*)malloc(sizeof(char) * (n + 1))) == NULL)
+		return (NULL);
+	i = 0;
+	while (i < n)
+	{
+		clone[i] = s1[i];
+		i++;
+	}
+	clone[i] = '\0';
+	return (clone);
+}
+
+char	*ft_strrchr(const char *s, int c)
+{
+	int i;
+
+	i = ft_strlen(s) - 1;
+	while (s[i] != (char)c)
+	{
+		if (i == 0)
+			return (NULL);
+		i--;
+	}
+	return ((char*)s + i);
+}
+
+int		strrchr_index(const char *s, char c)
+{
+	int i;
+
+	i = ft_strlen(s) - 1;
+	while (s[i] != c)
+	{
+		if (i == 0)
+			return (-1);
+		i--;
+	}
+	return (i);
+
+}
+
+int		ft_strlen(char *str)
+{
+	int	counter;
+
+	counter = 0;
+	while (str[counter])
+		counter++;
+	return (counter);
+}