Add linecmp()

libutil/linecmp.c

@@ -0,0 +1,20 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdio.h>
+#include <string.h>
+
+#include "../text.h"
+#include "../util.h"
+
+int
+linecmp(struct line *a, struct line *b)
+{
+	int res = 0;
+
+	if (!(res = memcmp(a->data, b->data, MIN(a->len, b->len))) &&
+	    a->len != b->len) {
+		res = a->data[MIN(a->len, b->len) - 1] -
+		      b->data[MIN(a->len, b->len) - 1];
+	}
+
+	return res;
+}