Saveload: Add wrapper to simplify conditionally upstream chunks

Where they're always saved as upstream and conditional on a feature

src/settings.cpp

@@ -3693,28 +3693,9 @@ static void Check_PATX()
 	LoadSettingsPatx(&_load_check_data.settings);
 }
 
-struct PATSChunkInfo
-{
-	static SaveLoadVersion GetLoadVersion()
-	{
-		extern SaveLoadVersion _sl_xv_upstream_version;
-		return _sl_xv_upstream_version;
-	}
-
-	static bool SaveUpstream()
-	{
-		return true;
-	}
-
-	static bool LoadUpstream()
-	{
-		return SlXvIsFeaturePresent(XSLFI_TABLE_PATS);
-	}
-};
-
 static const ChunkHandler setting_chunk_handlers[] = {
 	{ 'OPTS', nullptr,   Load_OPTS, nullptr, nullptr,    CH_RIFF },
-	MakeConditionallyUpstreamChunkHandler<'PATS', PATSChunkInfo>(nullptr, Load_PATS, nullptr, Check_PATS, CH_RIFF),
+	MakeSaveUpstreamFeatureConditionalLoadUpstreamChunkHandler<'PATS', XSLFI_TABLE_PATS>(Load_PATS, nullptr, Check_PATS),
 	{ 'PATX', nullptr,   Load_PATX, nullptr, Check_PATX, CH_RIFF },
 };
 

src/sl/saveload.h

@@ -133,6 +133,26 @@ void SlExecWithSlVersion(SaveLoadVersion use_version, F proc)
 	proc();
 }
 
+template <SlXvFeatureIndex feature, uint16_t min_version, uint16_t max_version>
+struct SaveUpstreamFeatureConditionalLoadUpstreamChunkInfo
+{
+	static SaveLoadVersion GetLoadVersion()
+	{
+		extern SaveLoadVersion _sl_xv_upstream_version;
+		return _sl_xv_upstream_version;
+	}
+
+	static bool SaveUpstream()
+	{
+		return true;
+	}
+
+	static bool LoadUpstream()
+	{
+		return SlXvIsFeaturePresent(feature, min_version, max_version);
+	}
+};
+
 namespace upstream_sl {
 	template <uint32_t id, typename F>
 	ChunkHandler MakeUpstreamChunkHandler()
@@ -220,10 +240,17 @@ namespace upstream_sl {
 		};
 		return ch;
 	}
+
+	template <uint32_t id, SlXvFeatureIndex feature, uint16_t min_version = 1, uint16_t max_version = 0xFFFF>
+	ChunkHandler MakeSaveUpstreamFeatureConditionalLoadUpstreamChunkHandler(ChunkSaveLoadProc *load_proc, ChunkSaveLoadProc *ptrs_proc, ChunkSaveLoadProc *load_check_proc)
+	{
+		return MakeConditionallyUpstreamChunkHandler<id, SaveUpstreamFeatureConditionalLoadUpstreamChunkInfo<feature, min_version, max_version>>(nullptr, load_proc, ptrs_proc, load_check_proc, CH_UNUSED);
+	}
 }
 
 using upstream_sl::MakeUpstreamChunkHandler;
 using upstream_sl::MakeConditionallyUpstreamChunkHandler;
+using upstream_sl::MakeSaveUpstreamFeatureConditionalLoadUpstreamChunkHandler;
 
 struct NullStruct {
 	byte null;