support re-use of thumbnail images

strukturag · Mar 23, 2024 · 26dbaf3 · 26dbaf3
1 parent b5c8179
commit 26dbaf3
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Showing 2 changed files with 20 additions and 27 deletions.
diff --git a/libheif/context.cc b/libheif/context.cc
@@ -656,34 +656,29 @@ Error HeifContext::interpret_heif_file()
           // --- this is a thumbnail image, attach to the main image
 
           std::vector<heif_item_id> refs = ref.to_item_ID;
-          if (refs.size() != 1) {
-            return Error(heif_error_Invalid_input,
-                         heif_suberror_Unspecified,
-                         "Too many thumbnail references");
-          }
+          for (heif_item_id ref: refs) {
+            image->set_is_thumbnail();
 
-          image->set_is_thumbnail_of(refs[0]);
-
-          auto master_iter = m_all_images.find(refs[0]);
-          if (master_iter == m_all_images.end()) {
-            return Error(heif_error_Invalid_input,
-                         heif_suberror_Nonexisting_item_referenced,
-                         "Thumbnail references a non-existing image");
-          }
+            auto master_iter = m_all_images.find(ref);
+            if (master_iter == m_all_images.end()) {
+              return Error(heif_error_Invalid_input,
+                          heif_suberror_Nonexisting_item_referenced,
+                          "Thumbnail references a non-existing image");
+            }
 
-          if (master_iter->second->is_thumbnail()) {
-            return Error(heif_error_Invalid_input,
-                         heif_suberror_Nonexisting_item_referenced,
-                         "Thumbnail references another thumbnail");
-          }
+            if (master_iter->second->is_thumbnail()) {
+              return Error(heif_error_Invalid_input,
+                          heif_suberror_Nonexisting_item_referenced,
+                          "Thumbnail references another thumbnail");
+            }
 
-          if (image.get() == master_iter->second.get()) {
-            return Error(heif_error_Invalid_input,
-                         heif_suberror_Nonexisting_item_referenced,
-                         "Recursive thumbnail image detected");
+            if (image.get() == master_iter->second.get()) {
+              return Error(heif_error_Invalid_input,
+                          heif_suberror_Nonexisting_item_referenced,
+                          "Recursive thumbnail image detected");
+            }
+            master_iter->second->add_thumbnail(image);
           }
-          master_iter->second->add_thumbnail(image);
-
           remove_top_level_image(image);
         }
         else if (type == fourcc("auxl")) {

diff --git a/libheif/context.h b/libheif/context.h
@@ -134,10 +134,9 @@ class HeifContext : public ErrorBuffer
 
     // -- thumbnails
 
-    void set_is_thumbnail_of(heif_item_id id)
+    void set_is_thumbnail()
     {
       m_is_thumbnail = true;
-      m_thumbnail_ref_id = id;
     }
 
     void add_thumbnail(const std::shared_ptr<Image>& img) { m_thumbnails.push_back(img); }
@@ -290,7 +289,6 @@ class HeifContext : public ErrorBuffer
     bool m_is_primary = false;
 
     bool m_is_thumbnail = false;
-    heif_item_id m_thumbnail_ref_id = 0;
 
     std::vector<std::shared_ptr<Image>> m_thumbnails;