The Sega static analyser now attempts to differentiate region and paging scheme.

Analyser/Static/Sega/StaticAnalyser.cpp

@@ -11,6 +11,9 @@
 #include "Target.hpp"
 
 Analyser::Static::TargetList Analyser::Static::Sega::GetTargets(const Media &media, const std::string &file_name, TargetPlatform::IntType potential_platforms) {
+	if(media.cartridges.empty())
+		return {};
+
 	TargetList targets;
 	std::unique_ptr<Target> target(new Target);
 
@@ -23,10 +26,53 @@ Analyser::Static::TargetList Analyser::Static::Sega::GetTargets(const Media &med
 		target->model = Target::Model::MasterSystem;
 	}
 
+	// If this is a Master System title, look for a ROM header.
+	if(target->model == Target::Model::MasterSystem) {
+		const auto &data = media.cartridges.front()->get_segments()[0].data;
+
+		// First try to locate a header.
+		size_t header_offset = 0;
+		size_t potential_offsets[] = {0x1ff0, 0x3ff0, 0x7ff0};
+		for(auto potential_offset: potential_offsets) {
+			if(!memcmp(&data[potential_offset], "TMR SEGA", 8)) {
+				header_offset = potential_offset;
+				break;
+			}
+		}
+
+		// If a header was found, use it to crib region.
+		if(header_offset) {
+			// Treat export titles as European by default; decline to
+			// do so only if (US) or (NTSC) is in the file name.
+			const uint8_t region = data[header_offset + 0x0f] >> 4;
+			switch(region) {
+				default: break;
+				case 4: {
+					std::string lowercase_name = file_name;
+					std::transform(lowercase_name.begin(), lowercase_name.end(), lowercase_name.begin(), ::tolower);
+					if(lowercase_name.find("(jp)") != std::string::npos) {
+						target->region =
+							(lowercase_name.find("(us)") == std::string::npos &&
+							lowercase_name.find("(ntsc)") == std::string::npos) ? Target::Region::Europe : Target::Region::USA;
+					}
+				} break;
+			}
+
+			// Also check for a Codemasters header.
+			// If one is found, set the paging scheme appropriately.
+			const uint16_t inverse_checksum = uint16_t(0x10000 - (data[0x7fe6] | (data[0x7fe7] << 8)));
+			if(
+				data[0x7fe3] >= 0x87 && data[0x7fe3] < 0x96 &&									// i.e. game is dated between 1987 and 1996
+				(inverse_checksum&0xff) == data[0x7fe8] &&
+				(inverse_checksum >> 8) == data[0x7fe9] &&										// i.e. the standard checksum appears to be present
+				!data[0x7fea] && !data[0x7feb] && !data[0x7fec] && !data[0x7fed] && !data[0x7fee] && !data[0x7fef]
+			) {
+				target->paging_scheme = Target::PagingScheme::Codemasters;
+			}
+		}
+	}
+
 	target->media.cartridges = media.cartridges;
-
-	if(!target->media.empty())
-		targets.push_back(std::move(target));
-
+	targets.push_back(std::move(target));
 	return targets;
 }

Analyser/Static/Sega/Target.hpp

@@ -19,7 +19,20 @@ struct Target: public ::Analyser::Static::Target {
 		SG1000
 	};
 
+	enum class Region {
+		Japan,
+		USA,
+		Europe
+	};
+
+	enum class PagingScheme {
+		Sega,
+		Codemasters
+	};
+
 	Model model = Model::MasterSystem;
+	Region region = Region::Japan;
+	PagingScheme paging_scheme = PagingScheme::Sega;
 };
 
 }