Cleanup, add scanline mask builder

PortabilityLayer/ScanlineMask.h

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <stdint.h>
+
+namespace PortabilityLayer
+{
+	class ScanlineMaskBuilder;
+
+	class ScanlineMask
+	{
+	public:
+		void Destroy();
+
+		static ScanlineMask *Create(const ScanlineMaskBuilder &builder);
+
+	private:
+		enum DataStorage
+		{
+			DataStorage_UInt8,
+			DataStorage_UInt16,
+			DataStorage_UInt32,
+		};
+
+		explicit ScanlineMask(DataStorage dataStorage, const void *data, size_t numSpans);
+		~ScanlineMask();
+
+		const DataStorage m_dataStorage;
+		const void *m_data;
+		const size_t m_numSpans;
+	};
+}