From db66484c4300f5f0e857eff01d15fd3593002a79 Mon Sep 17 00:00:00 2001
From: David Härdeman <david@hardeman.nu>
Date: Fri, 5 Jun 2020 14:09:18 +0200
Subject: Initial commit

---
 utils.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100644 utils.c

(limited to 'utils.c')

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;
+}
+
-- 
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