1 files changed, 71 insertions, 0 deletions
diff --git a/lib/getrange.c b/lib/getrange.c
new file mode 100644
index 0000000..466e908
--- /dev/null
+++ b/lib/getrange.c
@@ -0,0 +1,71 @@
+// SPDX-FileCopyrightText: 2008, Nicolas François
+// SPDX-FileCopyrightText: 2023-2024, Alejandro Colomar <alx@kernel.org>
+// SPDX-License-Identifier: BSD-3-Clause
+
+
+#include <config.h>
+
+#ident "$Id: $"
+
+#include <ctype.h>
+#include <stdlib.h>
+
+#include "atoi/a2i.h"
+#include "defines.h"
+#include "prototypes.h"
+
+
+/*
+ * Parse a range and indicate if the range is valid.
+ * Valid ranges are in the form:
+ *     <long>          -> min=max=long         has_min  has_max
+ *     -<long>         -> max=long            !has_min  has_max
+ *     <long>-         -> min=long             has_min !has_max
+ *     <long1>-<long2> -> min=long1 max=long2  has_min  has_max
+ */
+int
+getrange(const char *range,
+         unsigned long *min, bool *has_min,
+         unsigned long *max, bool *has_max)
+{
+	const char  *end;
+
+	if (NULL == range)
+		return -1;
+
+	*min = 0;
+	*has_min = false;
+	*has_max = false;
+
+	if ('-' == range[0]) {
+		end = range + 1;
+		goto parse_max;
+	}
+
+	if (a2ul(min, range, &end, 10, 0, ULONG_MAX) == -1 && errno != ENOTSUP)
+		return -1;
+	*has_min = true;
+
+	switch (*end++) {
+	case '\0':
+		*has_max = true;
+		*max = *min;
+		return 0;  /* <long> */
+
+	case '-':
+		if ('\0' == *end)
+			return 0;  /* <long>- */
+parse_max:
+		if (!isdigit((unsigned char) *end))
+			return -1;
+
+		if (a2ul(max, end, NULL, 10, *min, ULONG_MAX) == -1)
+			return -1;
+		*has_max = true;
+
+		return 0;  /* <long>-<long>, or -<long> */
+
+	default:
+		return -1;
+	}
+}