1 files changed, 76 insertions, 0 deletions
diff --git a/lib/fstree/fstree_sort.c b/lib/fstree/fstree_sort.c
new file mode 100644
index 0000000..9f07c92
--- /dev/null
+++ b/lib/fstree/fstree_sort.c
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+#include "fstree.h"
+
+#include <string.h>
+
+static tree_node_t *sort_list(tree_node_t *head)
+{
+	tree_node_t *it, *prev, *lhs, *rhs;
+	size_t i, count = 0;
+
+	for (it = head; it != NULL; it = it->next)
+		++count;
+
+	if (count < 2)
+		return head;
+
+	prev = NULL;
+	it = head;
+
+	for (i = 0; i < count / 2; ++i) {
+		prev = it;
+		it = it->next;
+	}
+
+	prev->next = NULL;
+
+	lhs = sort_list(head);
+	rhs = sort_list(it);
+
+	head = NULL;
+	prev = NULL;
+
+	while (lhs != NULL && rhs != NULL) {
+		if (strcmp(lhs->name, rhs->name) <= 0) {
+			it = lhs;
+			lhs = lhs->next;
+		} else {
+			it = rhs;
+			rhs = rhs->next;
+		}
+
+		it->next = NULL;
+
+		if (prev != NULL) {
+			prev->next = it;
+			prev = it;
+		} else {
+			prev = head = it;
+		}
+	}
+
+	it = (lhs != NULL ? lhs : rhs);
+
+	if (prev != NULL) {
+		prev->next = it;
+	} else {
+		head = it;
+	}
+
+	return head;
+}
+
+static void sort_directory(tree_node_t *n)
+{
+	n->data.dir->children = sort_list(n->data.dir->children);
+
+	for (n = n->data.dir->children; n != NULL; n = n->next) {
+		if (S_ISDIR(n->mode))
+			sort_directory(n);
+	}
+}
+
+void fstree_sort(fstree_t *fs)
+{
+	sort_directory(fs->root);
+}