enh(Any): reduce memory usage for small object optimisation.

pocoproject · Dec 20, 2024 · 4f4520f · 4f4520f
1 parent c19156e
commit 4f4520f
Showing 1 changed file with 10 additions and 5 deletions.
diff --git a/Foundation/include/Poco/Any.h b/Foundation/include/Poco/Any.h
@@ -78,7 +78,7 @@ union Placeholder
 
 #ifndef POCO_NO_SOO
 
-	Placeholder(): pHolder(nullptr)
+	Placeholder()
 	{
 		// Forces to use optimised memset internally
 		// https://travisdowns.github.io/blog/2020/01/20/zero.html
@@ -168,6 +168,7 @@ union Placeholder
 			break;
 		case Allocation::POCO_ANY_LOCAL:
 			{
+				// Do not deallocate, just explicitly call destructor
 				auto* h { reinterpret_cast<PlaceholderT*>(holder) };
 				h->~PlaceholderT();
 			}
@@ -183,16 +184,20 @@ union Placeholder
 			poco_bugcheck();
 			break;
 		}
+		setAllocation(Allocation::POCO_ANY_EMPTY);
 		if (clear)
 		{
 			// Force to use optimised memset internally
 			std::fill(std::begin(holder), std::end(holder), static_cast<char>(0));
 		}
-		setAllocation(Allocation::POCO_ANY_EMPTY);
 	}
 
-	mutable unsigned char holder[SizeV+1];
-	AlignerType           aligner;
+	// Either store small object or a pointer to a placeholder
+	union
+	{
+		mutable unsigned char holder[SizeV+1];
+		PlaceholderT* pHolder;
+	};
 
 #else // POCO_NO_SOO
 
@@ -239,8 +244,8 @@ union Placeholder
 	}
 
 private:
-#endif // POCO_NO_SOO
 	PlaceholderT* pHolder;
+#endif // POCO_NO_SOO
 };