/*

 * Copyright (c) 2000, 2005, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.imageio.plugins.common;

import java.io.IOException;

import javax.imageio.stream.ImageInputStreamImpl;

import javax.imageio.stream.ImageInputStream;

public final class SubImageInputStream extends ImageInputStreamImpl {

    ImageInputStream stream;

    long startingPos;

    int startingLength;

    int length;

    public SubImageInputStream(ImageInputStream stream, int length)

        throws IOException {

        this.stream = stream;

        this.startingPos = stream.getStreamPosition();

        this.startingLength = this.length = length;

    }

    public int read() throws IOException {

        if (length == 0) { // Local EOF

            return -1;

        } else {

            --length;

            return stream.read();

        }

    }

    public int read(byte[] b, int off, int len) throws IOException {

        if (length == 0) { // Local EOF

            return -1;

        }

        len = Math.min(len, length);

        int bytes = stream.read(b, off, len);

        length -= bytes;

        return bytes;

    }

    public long length() {

        return startingLength;

    }

    public void seek(long pos) throws IOException {

        stream.seek(pos - startingPos);

        streamPos = pos;

    }

    protected void finalize() throws Throwable {

        // Empty finalizer (for improved performance; no need to call

        // super.finalize() in this case)

    }

}