From 45ac758cc9336168fee1ce24e144347babafeda7 Mon Sep 17 00:00:00 2001
From: James Turner <zakalawe@mac.com>
Date: Tue, 27 Dec 2016 11:09:07 +0000
Subject: [PATCH] Expose position on SGPropertyNode.

---
 simgear/props/props.cxx      | 14 ++++++++++++--
 simgear/props/props.hxx      |  4 ++++
 simgear/props/props_test.cxx |  9 +++++++++
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/simgear/props/props.cxx b/simgear/props/props.cxx
index aa1baf31..49dbdad8 100644
--- a/simgear/props/props.cxx
+++ b/simgear/props/props.cxx
@@ -1100,7 +1100,7 @@ SGPropertyNode::addChildren( const std::string& name,
 }
 
 /**
- * Get a non-const child by index.
+ * Get a non-const child by position.
  */
 SGPropertyNode *
 SGPropertyNode::getChild (int position)
@@ -1113,7 +1113,7 @@ SGPropertyNode::getChild (int position)
 
 
 /**
- * Get a const child by index.
+ * Get a const child by position.
  */
 const SGPropertyNode *
 SGPropertyNode::getChild (int position) const
@@ -1124,6 +1124,16 @@ SGPropertyNode::getChild (int position) const
     return 0;
 }
 
+unsigned int SGPropertyNode::getPosition() const
+{
+    if (_parent == nullptr) {
+        return 0;
+    }
+
+    auto it = std::find(_parent->_children.begin(), _parent->_children.end(), this);
+    assert(it != _parent->_children.end());
+    return std::distance(_parent->_children.begin(), it);
+}
 
 /**
  * Get a non-const child by name and index, creating if necessary.
diff --git a/simgear/props/props.hxx b/simgear/props/props.hxx
index dcbd9a24..84552a32 100644
--- a/simgear/props/props.hxx
+++ b/simgear/props/props.hxx
@@ -848,6 +848,10 @@ public:
    */
   const SGPropertyNode * getParent () const { return _parent; }
 
+    /**
+     * Get node's position in parent (*NOT* index)
+     */
+    unsigned int getPosition() const;
 
   //
   // Children.
diff --git a/simgear/props/props_test.cxx b/simgear/props/props_test.cxx
index a6f41b8b..0cc63450 100644
--- a/simgear/props/props_test.cxx
+++ b/simgear/props/props_test.cxx
@@ -310,12 +310,19 @@ test_property_nodes ()
   grandchild->setDoubleValue(100);
   grandchild = child->getChild("bar", 3, true);
   grandchild->setDoubleValue(200);
+
+    SG_CHECK_EQUAL(grandchild->getPosition(), 1);
+
+
   grandchild = child->getChild("bar", 1, true);
   grandchild->setDoubleValue(300);
   grandchild = child->getChild("bar", 2, true);
   grandchild->setDoubleValue(400);
   dump_node(&root);
 
+    SG_CHECK_EQUAL(child->getPosition(), 1);
+    SG_CHECK_EQUAL(grandchild->getPosition(), 3);
+
   cout << "Trying path (expect /foo[0]/bar[0])" << endl;
   grandchild = root.getNode("/hack/../foo/./bar[0]");
   cout << "Path is " << grandchild->getPath() << endl;
@@ -333,6 +340,8 @@ test_property_nodes ()
     cerr << "** FAILED to create /a/b/c" << endl;
   dump_node(&root);
   cout << endl;
+
+
 }
 
 void test_addChild()