BLI: add Map.lookup_or_add_default method

1 files changed, 13 insertions, 0 deletions

diff --git a/source/blender/blenlib/BLI_map.hh b/source/blender/blenlib/BLI_map.hh
index eb9c6372995..ea5e5da4099 100644
--- a/source/blender/blenlib/BLI_map.hh
+++ b/source/blender/blenlib/BLI_map.hh
@@ -408,6 +408,19 @@ class Map {
   }
 
   /**
+   * Return the value that corresponds to the given key.
+   * If it does not exist yet, insert a new default constructed value and return that.
+   */
+  ValueT &lookup_or_add_default(const KeyT &key)
+  {
+    return this->lookup_or_add(key, []() { return ValueT(); });
+  }
+  ValueT &lookup_or_add_default(const KeyT &&key)
+  {
+    return this->lookup_or_add(std::move(key), []() { return ValueT(); });
+  }
+
+  /**
    * Get the number of elements in the map.
    */
   uint32_t size() const