SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.runtime.swm;

import java.io.ByteArrayInputStream;
import java.io.InputStream;

/**
 * This class provides a stream of a JAR file through a byte array.
 *
 * @since 2017/12/28
 */
public final class ByteArrayJarStreamSupplier
    implements JarStreamSupplier
{
    /** The offset. */
    protected final int offset;
    
    /** The length. */
    protected final int length;
    
    /** The byte array. */
    private final byte[] _data;
    
    /**
     * Initializes the stream supplier for a simple byte array.
     *
     * @param __b The byte array to wrap.
     * @param __o The offset into the array.
     * @param __l The number of bytes to read.
     * @throws ArrayIndexOutOfBoundsException If the offset and/or length
     * are negative or exceed the array bounds.
     * @throws NullPointerException On null arguments.
     * @since 2017/12/28
     */
    public ByteArrayJarStreamSupplier(byte[] __b, int __o, int __l)
        throws ArrayIndexOutOfBoundsException, NullPointerException
    {
        if (__b == null)
            throw new NullPointerException("NARG");
        if (__o < 0 || __l < 0 || (__o + __l) < 0 || (__o + __l) > __b.length)
            throw new ArrayIndexOutOfBoundsException("IOOB");
        
        this._data = __b;
        this.offset = __o;
        this.length = __l;
    }
    
    /**
     * {@inheritDoc}
     * @since 2017/12/28
     */
    @Override
    public InputStream get()
    {
        return new ByteArrayInputStream(this._data, this.offset, this.length);
    }
}