sort properties such that descriptive properties precede transformative properties (#1443)

Author: farindk

libheif/box.cc

@@ -3147,6 +3147,27 @@ void Box_ipma::insert_entries_from_other_ipma_box(const Box_ipma& b)
 }
 
 
+void Box_ipma::sort_properties(const std::shared_ptr<Box_ipco>& ipco)
+{
+  auto properties = ipco->get_all_child_boxes();
+
+  for (auto& item : m_entries) {
+    size_t nAssoc = item.associations.size();
+
+    // simple Bubble sort as a stable sorting algorithm
+
+    for (size_t n = 0; n < nAssoc - 1; n++)
+      for (size_t i = 0; i < nAssoc - 1 - n; i++) {
+        // If transformative property preceds descriptive property, swap them.
+        if (properties[item.associations[i].property_index - 1]->is_transformative_property() &&
+            !properties[item.associations[i + 1].property_index - 1]->is_transformative_property()) {
+          std::swap(item.associations[i], item.associations[i+1]);
+        }
+      }
+  }
+}
+
+
 Error Box_auxC::parse(BitstreamRange& range, const heif_security_limits* limits)
 {
   parse_full_box_header(range);

libheif/box.h

@@ -260,6 +260,8 @@ class Box : public BoxHeader
 
   void set_is_essential(bool flag) { m_is_essential = flag; }
 
+  virtual bool is_transformative_property() const { return false; } // only used for properties
+
 protected:
   virtual Error parse(BitstreamRange& range, const heif_security_limits* limits);
 
@@ -802,6 +804,9 @@ class Box_ipma : public FullBox
 
   void insert_entries_from_other_ipma_box(const Box_ipma& b);
 
+  // sorts properties such that descriptive properties precede the transformative properties
+  void sort_properties(const std::shared_ptr<Box_ipco>&);
+
 protected:
   Error parse(BitstreamRange& range, const heif_security_limits*) override;
 
@@ -854,6 +859,8 @@ class Box_irot : public Box
 
   bool is_essential() const override { return true; }
 
+  bool is_transformative_property() const override { return true; }
+
   std::string dump(Indent&) const override;
 
   int get_rotation_ccw() const { return m_rotation; }
@@ -883,6 +890,8 @@ class Box_imir : public Box
 
   bool is_essential() const override { return true; }
 
+  bool is_transformative_property() const override { return true; }
+
   heif_transform_mirror_direction get_mirror_direction() const { return m_axis; }
 
   void set_mirror_direction(heif_transform_mirror_direction dir) { m_axis = dir; }
@@ -911,6 +920,8 @@ class Box_clap : public Box
 
   bool is_essential() const override { return true; }
 
+  bool is_transformative_property() const override { return true; }
+
   std::string dump(Indent&) const override;
 
   int left_rounded(uint32_t image_width) const;  // first column

libheif/context.cc

@@ -276,6 +276,10 @@ void HeifContext::write(StreamWriter& writer)
     img.second->process_before_write();
   }
 
+  // --- sort item properties
+
+  m_heif_file->get_ipma_box()->sort_properties(m_heif_file->get_ipco_box());
+
   // --- write to file
 
   m_heif_file->write(writer);