avoid copy construction for cartridge

1 files changed, 18 insertions, 42 deletions

diff --git a/lib/nes/sys/cartridge.cc b/lib/nes/sys/cartridge.cc
index 43f9430..fcb7e84 100644
--- a/lib/nes/sys/cartridge.cc
+++ b/lib/nes/sys/cartridge.cc
@@ -5,68 +5,44 @@
 
 namespace nes::sys
 {
-	cartridge::cartridge(status const status)
-		: status_{ status }
-	{
-	}
-
-	auto cartridge::from_data(void const* data, u32 const length) -> cartridge
+	cartridge::cartridge(u8 const* data, u32 const length)
 	{
 		// See: https://www.nesdev.org/wiki/INES
 
 		auto const bytes = static_cast<u8 const*>(data);
-		auto res = cartridge{ status::success };
 
 		// Parse header.
-		if (length < header_length) { return cartridge{ status::error_invalid_ines_data }; }
+		if (length < header_length) { return; }
 		auto const h = header{ bytes };
 		if (h.get_magic_0() != 'N' || h.get_magic_1() != 'E' || h.get_magic_2() != 'S' || h.get_magic_3() != 0x1A)
 		{
-			return cartridge{ status::error_invalid_ines_data };
+			return;
 		}
 		auto const mapper_number = static_cast<u8>((h.get_mapper_high() << 4) | (h.get_mapper_low() << 0));
 
-		res.mapper_ = &mapper::get(mapper_number);
-		res.name_table_arrangement_ = h.get_name_table_arrangement();
+		mapper_ = &mapper::get(mapper_number);
+		name_table_arrangement_ = h.get_name_table_arrangement();
 
 		// Load program data.
 		auto offset = u32{ 16 };
 		if (h.get_has_trainer()) { offset += 512; }
 
-		res.prg_rom_size_ = h.get_prg_rom_banks() * prg_rom_bank_size;
-		if (length < offset + res.prg_rom_size_) { return cartridge{ status::error_invalid_ines_data }; }
-		if (res.prg_rom_size_ > max_prg_rom_size) { return cartridge{ status::error_invalid_ines_data }; }
-		std::copy_n(&bytes[offset], res.prg_rom_size_, res.prg_rom_);
+		prg_rom_size_ = h.get_prg_rom_banks() * prg_rom_bank_size;
+		if (length < offset + prg_rom_size_) { return; }
+		if (prg_rom_size_ > max_prg_rom_size) { return; }
+		std::copy_n(&bytes[offset], prg_rom_size_, prg_rom_);
 
-		offset += res.prg_rom_size_;
+		offset += prg_rom_size_;
 
-		res.chr_rom_size_ = h.get_chr_rom_banks() * chr_rom_bank_size;
-		if (length < offset + res.chr_rom_size_) { return cartridge{ status::error_invalid_ines_data }; }
-		if (res.chr_rom_size_ > max_chr_rom_size) { return cartridge{ status::error_invalid_ines_data }; }
-		std::copy_n(&bytes[offset], res.chr_rom_size_, res.chr_rom_);
-
-		res.ram_size_ = std::max(h.get_ram_banks(), 1u) * ram_bank_size;
-		if (res.ram_size_ > max_ram_size) { return cartridge{ status::error_invalid_ines_data }; }
-
-		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{ status::error_system_error }; }
+		chr_rom_size_ = h.get_chr_rom_banks() * chr_rom_bank_size;
+		if (length < offset + chr_rom_size_) { return; }
+		if (chr_rom_size_ > max_chr_rom_size) { return; }
+		std::copy_n(&bytes[offset], chr_rom_size_, chr_rom_);
 
-		stream.seekg(0, std::ios::end);
-		auto const length = stream.tellg();
-		stream.seekg(0, std::ios::beg);
-		auto data = std::vector<u8>(static_cast<u32>(length));
-		stream.read(reinterpret_cast<char*>(data.data()), length);
+		ram_size_ = std::max(h.get_ram_banks(), 1u) * ram_bank_size;
+		if (ram_size_ > max_ram_size) { return; }
 
-		return from_data(data.data(), static_cast<u32>(length));
+		status_ = get_mapper().validate(*this);
+		if (status_ != status::success) { return; }
 	}
 } // namespace nes::sys
\ No newline at end of file