ROM

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;

/**
 * Represents a single Gameboy or Gameboy Color ROM.
 *
 * @author Ryan Greene
 *
 */
public final class ROM {

    /**
     * The file where the ROM is located.
     */
    private final File file;

    /**
     * The input stream used to read the ROM.
     */
    private final InputStream input;

    /**
     * The bytes which make up the ROM.
     */
    private final byte[] data;

    /**
     * Title of the game in UPPER CASE ASCII. If it is less than 16 characters
     * then the remaining bytes are filled with 00's. When inventing the CGB,
     * Nintendo has reduced the length of this area to 15 characters, and some
     * months later they had the fantastic idea to reduce it to 11 characters
     * only.
     */
    private final String title;

    /**
     * In older cartridges this area has been part of the Title, in newer
     * cartridges this area contains an 4 character uppercase manufacturer code.
     * Purpose and Deeper Meaning unknown.
     */
    private final String manufacturerCode;

    /**
     * In older cartridges this byte has been part of the Title. In CGB
     * cartridges the upper bit is used to enable CGB functions. This is
     * required, otherwise the CGB switches itself into Non-CGB-Mode.
     */
    private final boolean cgb;

    /**
     * Specifies a two character ASCII licensee code, indicating the company or
     * publisher of the game. These two bytes are used in newer games only
     * (games that have been released after the SGB has been invented). Older
     * games are using the header entry at 014B instead.
     */
    private final String newLicenseeCode;

    /**
     * Specifies whether the game supports SGB functions.
     */
    private final boolean sgb;

    /**
     * Constructs a new ROM from the specified directory.
     *
     * @param directory
     *            The directory the ROM is located.
     * @throws IOException
     *             If an exception occurs while constructing the ROM.
     */
    public ROM(final String directory) throws IOException {
        file = new File(directory);
        input = new FileInputStream(file);
        data = new byte[(int) file.length()];
        input.read(data);

        title = new String(data, 0x134, 11, Charset.forName("US-ASCII"));
        manufacturerCode = new String(data, 0x13F, 4);
        cgb = data[0x143] == 0xC0 ? true : false;
        newLicenseeCode = new String(data, 0x144, 2, Charset.forName("US-ASCII"));
        sgb = data[0x164] == 0x3 ? true : false;
    }
}