2 files changed, 4 insertions, 4 deletions

diff --git a/include/plist/Array.h b/include/plist/Array.h
index 69ff26f..745b750 100644
--- a/include/plist/Array.h
+++ b/include/plist/Array.h
@@ -44,7 +44,7 @@ public :
     void Insert(Node* node, unsigned int pos);
     void Remove(Node* node);
     void Remove(unsigned int pos);
-    unsigned int GetNodeIndex(Node* node);
+    unsigned int GetNodeIndex(Node* node) const;
 
 private :
     std::vector<Node*> _array;
diff --git a/include/plist/Structure.h b/include/plist/Structure.h
index 8e609da..eded8b2 100644
--- a/include/plist/Structure.h
+++ b/include/plist/Structure.h
@@ -34,10 +34,10 @@ class Structure : public Node
 public :
     virtual ~Structure();
 
-    uint32_t GetSize();
+    uint32_t GetSize() const;
 
-    std::string ToXml();
-    std::vector<char> ToBin();
+    std::string ToXml() const;
+    std::vector<char> ToBin() const;
 
     virtual void Remove(Node* node) = 0;