libfdt: Add fdt_parent_offset() and supporting functions

This patch adds an fdt_parent_offset() function which returns an
offset to the parent node of a given node.  It also adds two helper
functions which are used to implement fdt_parent_offset() but are also
exported: fdt_supernode_atdepth_offset() which returns the ancestor of
a given node at a specified depth from the root of the tree, and
fdt_node_depth() which returns the depth of a given node.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 90 insertions, 0 deletions

diff --git a/tests/parent_offset.c b/tests/parent_offset.c
new file mode 100644
index 0000000..f3d2c32
--- /dev/null
+++ b/tests/parent_offset.c
@@ -0,0 +1,90 @@
+/*
+ * libfdt - Flat Device Tree manipulation
+ *	Testcase for fdt_parent_offset()
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#define _GNU_SOURCE
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "tests.h"
+#include "testdata.h"
+
+int path_parent_len(const char *path)
+{
+	const char *p = strrchr(path, '/');
+
+	if (!p)
+		TEST_BUG();
+	if (p == path)
+		return 1;
+	else
+		return p - path;
+}
+
+void check_path(struct fdt_header *fdt, const char *path)
+{
+	char *parentpath;
+	int nodeoffset, parentoffset, parentpathoffset;
+
+	parentpath = strndupa(path, path_parent_len(path));
+
+	verbose_printf("Path: \"%s\"\tParent: \"%s\"\n", path, parentpath);
+
+	nodeoffset = fdt_path_offset(fdt, path);
+	if (nodeoffset < 0)
+		FAIL("fdt_path_offset(%s): %s", path, fdt_strerror(nodeoffset));
+
+	parentpathoffset = fdt_path_offset(fdt, parentpath);
+	if (parentpathoffset < 0)
+		FAIL("fdt_path_offset(%s): %s", parentpath,
+		     fdt_strerror(parentpathoffset));
+
+	parentoffset = fdt_parent_offset(fdt, nodeoffset);
+	if (parentoffset < 0)
+		FAIL("fdt_parent_offset(): %s", fdt_strerror(parentoffset));
+
+	if (parentoffset != parentpathoffset)
+		FAIL("fdt_parent_offset() returns %d instead of %d",
+		     parentoffset, parentpathoffset);
+}
+
+int main(int argc, char *argv[])
+{
+	void *fdt;
+	int err;
+
+	test_init(argc, argv);
+	fdt = load_blob_arg(argc, argv);
+
+	check_path(fdt, "/subnode1");
+	check_path(fdt, "/subnode2");
+	check_path(fdt, "/subnode1/subsubnode");
+	check_path(fdt, "/subnode2/subsubnode");
+	err = fdt_parent_offset(fdt, 0);
+	if (err != -FDT_ERR_NOTFOUND)
+		FAIL("fdt_parent_offset(/) returns %d instead of "
+		     "-FDT_ERR_NOTFOUND", err);
+
+	PASS();
+}