builtins

lib/libft/srcs/format/ft_atol.c

@@ -0,0 +1,48 @@
+#include "../../libft.h"
+
+static int	is_signed(char c, int *sign)
+{
+	if (c == '+' || c == '-')
+	{
+		if (c == '-')
+			*sign *= -1;
+		return (1);
+	}
+	return (0);
+}
+
+long	ft_atol(const char *str)
+{
+	long	res;
+	int		sign;
+
+	res = 0;
+	sign = 1;
+	errno = 0;
+	while (*str && ((*str >= 9 && *str <= 13) || *str == 32))
+		str++;
+	if (is_signed(*str, &sign))
+		str++;
+	while (*str >= '0' && *str <= '9')
+	{
+		if (((sign > 0) && res >= (LONG_MAX  / 10) && 
+			(*str - '0' > LONG_MAX % 10))
+			|| (sign == -1 &&  res >= LONG_MAX / 10 && *str - '0' > LONG_MAX % 10 + 1))
+		{
+			errno = ERANGE;
+			break;
+		}
+		res = (res * 10) + (*str - '0');
+		str++;
+	}
+	return (res * sign);
+}
+//
+// #include <stdio.h>
+//
+// int main(int ac, char **av)
+// {
+// 	printf("res: %ld\n", ft_atol(av[1]));
+// 	printf("errno: %d\n", errno);
+//
+// }