1 files changed, 22 insertions, 15 deletions

diff --git a/lib/nes/cartridge.cc b/lib/nes/cartridge.cc
index d4ade23..6a60741 100644
--- a/lib/nes/cartridge.cc
+++ b/lib/nes/cartridge.cc
@@ -1,36 +1,38 @@
 #include "nes/cartridge.hh"
+#include "nes/util/status.hh"
 #include <fstream>
 
 namespace nes
 {
-	namespace
+	cartridge::cartridge(status const status)
+		: status_{ status }
 	{
-		constexpr auto prg_rom_bank_size = std::size_t{ 16 * 1024 };
-		constexpr auto chr_rom_bank_size = std::size_t{ 8 * 1024 };
-		constexpr auto ram_bank_size = std::size_t{ 8 * 1024 };
-	} // namespace
+	}
 
 	auto cartridge::from_data(void const* data, std::size_t const length) -> cartridge
 	{
 		// See: https://www.nesdev.org/wiki/INES
 
 		auto const bytes = static_cast<std::uint8_t const*>(data);
-		auto res = cartridge{};
-		res.is_valid_ = true;
+		auto res = cartridge{ status::success };
 
 		// Parse header.
-		if (length < 16) { return cartridge{}; }
-		if (bytes[0] != 'N' || bytes[1] != 'E' || bytes[2] != 'S' || bytes[3] != 0x1A) { return cartridge{}; }
+		if (length < 16) { return cartridge{ status::error_invalid_ines_data }; }
+		if (bytes[0] != 'N' || bytes[1] != 'E' || bytes[2] != 'S' || bytes[3] != 0x1A)
+		{
+			return cartridge{ status::error_invalid_ines_data };
+		}
 		auto const prg_rom_banks = bytes[4];
 		auto const chr_rom_banks = bytes[5];
 		auto const control_1 = bytes[6];
 		auto const control_2 = bytes[7];
 		auto const ram_banks = (bytes[8] != 0) ? bytes[8] : 1u;
 		auto const has_trainer = (control_1 & 0b00000100) != 0;
-
-		res.mapper_number_ =
+		auto const mapper_number = static_cast<std::uint8_t>(
 			(control_1 & 0b11110000) >> 4 |
-			(control_2 & 0b11110000) >> 0;
+			(control_2 & 0b11110000) >> 0);
+
+		res.mapper_ = &mapper::get(mapper_number);
 		res.name_table_arrangement_ = (control_1 & 0b00000001) != 0
 			? name_table_arrangement::vertical
 			: name_table_arrangement::horizontal;
@@ -40,24 +42,29 @@ namespace nes
 		if (has_trainer) { offset += 512; }
 
 		auto const prg_rom_size = prg_rom_banks * prg_rom_bank_size;
-		if (length < offset + prg_rom_size) { return cartridge{}; }
+		if (length < offset + prg_rom_size) { return cartridge{ status::error_invalid_ines_data }; }
 		res.prg_rom_ = std::vector(&bytes[offset], &bytes[offset + prg_rom_size]);
 
 		offset += prg_rom_size;
 
 		auto const chr_rom_size = chr_rom_banks * chr_rom_bank_size;
-		if (length < offset + chr_rom_size) { return cartridge{}; }
+		if (length < offset + chr_rom_size) { return cartridge{ status::error_invalid_ines_data }; }
 		res.chr_rom_ = std::vector(&bytes[offset], &bytes[offset + chr_rom_size]);
 
 		res.ram_ = std::vector(ram_banks * ram_bank_size, std::uint8_t{ 0 });
 
+		if (auto const status = res.get_mapper().validate(res); status != status::success)
+		{
+			return cartridge{ status };
+		}
+
 		return res;
 	}
 
 	auto cartridge::from_file(std::string_view const path) -> cartridge
 	{
 		auto stream = std::ifstream{ path, std::ios::binary };
-		if (!stream.good()) { return cartridge{}; }
+		if (!stream.good()) { return cartridge{ status::error_system_error }; }
 
 		stream.seekg(0, std::ios::end);
 		auto const length = stream.tellg();