WinGpuInfoLoader.java

import java.util.List;
import java.util.Optional;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.github.robtimus.os.windows.registry.BinaryValue;
import com.github.robtimus.os.windows.registry.DWordValue;
import com.github.robtimus.os.windows.registry.QWordValue;
import com.github.robtimus.os.windows.registry.RegistryKey;
import com.github.robtimus.os.windows.registry.RegistryValue;

public class WinGpuInfoLoader {
    public static final Logger LOG = LoggerFactory.getLogger(WinGpuInfoLoader.class);
    public static final String DISPLAY_DEVICES_REGISTRY_PATH =
            "SYSTEM\\CurrentControlSet\\Control\\Class\\{4d36e968-e325-11ce-bfc1-08002be10318}";
    public static final String ADAPTER_STRING = "HardwareInformation.AdapterString";
    public static final String DRIVER_DESC = "DriverDesc";
    public static final String QW_MEMORY_SIZE = "HardwareInformation.qwMemorySize";
    public static final String MEMORY_SIZE = "HardwareInformation.MemorySize";

    public List<GraphicCard> load() {
        RegistryKey gpuDevicesRegistryKey = RegistryKey.HKEY_LOCAL_MACHINE.resolve(DISPLAY_DEVICES_REGISTRY_PATH);

        return gpuDevicesRegistryKey
                .subKeys()
                .filter(sk -> sk.name().startsWith("0"))
                .filter(sk -> sk.findValue(ADAPTER_STRING, RegistryValue.class).isPresent())
                .map(sk -> {
                    String name = sk.findStringValue(DRIVER_DESC).orElse("<Unknown>");

                    long vram = getRegistryValueAsLong(sk.findValue(QW_MEMORY_SIZE, RegistryValue.class))
                            .orElseGet(() -> getRegistryValueAsLong(sk.findValue(MEMORY_SIZE, RegistryValue.class)).orElse(0L));

                    return new GraphicCard(name, vram);
                }).toList();
    }

    private static Optional<Long> getRegistryValueAsLong(Optional<RegistryValue> optionalValue) {
        if (optionalValue.isEmpty()) {
            return Optional.empty();
        }

        Long result = null;
        try {
            RegistryValue registryValue = optionalValue.get();
            if (registryValue instanceof QWordValue qWordValue) {
                result = qWordValue.value();
            } else if (registryValue instanceof DWordValue dWordValue) {
                result = (long) dWordValue.value();
            } else if (registryValue instanceof BinaryValue binaryValue) {
                result = bytesToLong(binaryValue.data());
            }
        } catch (RuntimeException e) {
            LOG.debug(e.getMessage(), e);
        }

        return Optional.ofNullable(result);
    }

    private static long bytesToLong(byte[] bytes) {
        long result = 0;

        if (bytes.length > 8) {
            throw new IllegalArgumentException("Oops! bytes length > 8");
        }

        for (byte i = 0; i < bytes.length; ++i) {
            result += (long) (bytes[i] & 255) << 8 * i;
        }

        return result;
    }
}