Rom.java

/**
 *  @author Clément Petit (282626)
 *  @author Yanis Berkani (271348)
 */

package ch.epfl.gameboj.component.memory;

import java.util.Arrays;
import java.util.Objects;

public final class Rom {
    private final byte[] rom;

    /**
     * builds the read-only memory which content and size are those of the
     * parameter.
     * 
     * @param data
     *            the array that provides the size and the content of the ROM
     *            (must not be null)
     * @throw the exception NullPointerException if it is null
     */
    public Rom(byte[] data) {
        Objects.requireNonNull(data);
        rom = Arrays.copyOf(data, data.length);
    }

    /**
     * return the size of the memory in bytes.
     * 
     * @return the size of the memory in bytes
     */
    public int size() {
        return rom.length;
    }

    /**
     * return the byte located at the index given.
     * 
     * @param index
     *            the index (must be included between 0 and FF)
     * @throws IndexOutOfBoundsException
     *             if the index is invalid
     * @return the byte located at the index given
     */
    public int read(int index) {
        if (index < 0 || index >= rom.length) {
            throw new IndexOutOfBoundsException();
        }
        return Byte.toUnsignedInt(rom[index]);
    }

}