Adding new function that gets the parent of a current node in a recursive structure

3 files changed, 55 insertions, 0 deletions

diff --git a/include/dtree/dtree.h b/include/dtree/dtree.h
index 7662412..a315014 100644
--- a/include/dtree/dtree.h
+++ b/include/dtree/dtree.h
@@ -189,6 +189,19 @@ dt_err dtree_merge_trees(dtree *data, dtree *merge);
 
 
 /**
+ * You can use this function to search the structure of a root node to find the
+ * parent of the node you provide as "data". It will leave the search pointer
+ * blanked if the node can't be found in the structure.
+ *
+ * @param root Root reference to search
+ * @param data The node we are searching for
+ * @param parent The node parent we are interested in
+ * @return
+ */
+dt_err dtree_parent(dtree *root, dtree *data, dtree **parent);
+
+
+/**
  * Recursive tree search function that will return the first occurence match
  * to a provided payload (with an exact type). If you have data duplication
  * in your tree this _might_ return some false positives.
diff --git a/lib/dtree.c b/lib/dtree.c
index 466c8c0..e45d453 100644
--- a/lib/dtree.c
+++ b/lib/dtree.c
@@ -335,6 +335,48 @@ dt_err dtree_copy_deep(dtree *data, dtree *(*copy))
     return err;
 }
 
+
+dt_err dtree_parent(dtree *root, dtree *data, dtree **parent)
+{
+    if(root == NULL || data == NULL) return INVALID_PARAMS;
+
+    /* Blank the search pointer for easy error checking */
+    (*parent) = NULL;
+
+    switch(data->type) {
+
+        /* Dead-end data stores automatically return @{NODE_NOT_FOUND} */
+        case POINTER:
+        case LITERAL:
+        case NUMERIC:
+            return NODE_NOT_FOUND;
+
+        case PAIR:
+        case LIST:
+            {
+                int i;
+                for(i = 0; i < root->used; i++) {
+
+                    /* Check if the node we're looking at is what we're searching for */
+                    if(root->payload.list[i] == data) {
+                        (*parent) = root;
+                        return SUCCESS;
+                    }
+
+                    dt_err err = dtree_parent(root->payload.list[i], data, parent);
+                    if(err == SUCCESS) return SUCCESS;
+                }
+            }
+            break;
+
+        default:
+            return INVALID_PAYLOAD;
+    }
+
+    return NODE_NOT_FOUND;
+}
+
+
 dt_err dtree_copy(dtree *data, dtree *(*copy))
 {
     if(data == NULL) return INVALID_PARAMS;
diff --git a/lib/dyn_utils.c b/lib/dtree_utils.c
index 6912dd2..6912dd2 100644
--- a/lib/dyn_utils.c
+++ b/lib/dtree_utils.c