Initial commit

1 files changed, 37 insertions, 0 deletions

diff --git a/utils.c b/utils.c
new file mode 100644
index 0000000..a84f63b
--- /dev/null
+++ b/utils.c
@@ -0,0 +1,37 @@
+#include <stdlib.h>
+#include <errno.h>
+#include <stdint.h>
+#include <limits.h>
+
+int
+strtou16_strict(const char *str, uint16_t *result)
+{
+	char *end;
+	long val;
+
+	if (!str)
+		return -EINVAL;
+
+	errno = 0;
+	val = strtol(str, &end, 10);
+
+	if (errno == ERANGE && (val == LONG_MAX || val == LONG_MIN))
+		return -EINVAL;
+	
+	if (errno != 0 && val == 0)
+		return -EINVAL;
+
+	if (end == str)
+		return -EINVAL;
+
+	if (*end != '\0')
+		return -EINVAL;
+
+	if (val < 1 || val > UINT16_MAX)
+		return -EINVAL;
+
+	if (result)
+		*result = val;
+	return 0;
+}
+