/*

 * Copyright (c) 1997, 2008, 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.

 */

/*

 * The Original Code is HAT. The Initial Developer of the

 * Original Code is Bill Foote, with contributions from others

 * at JavaSoft/Sun.

 */

package com.sun.tools.hat.internal.parser;

import java.io.*;

import com.sun.tools.hat.internal.model.*;

/**

 * Abstract base class for reading object dump files.  A reader need not be

 * thread-safe.

 *

 * @author      Bill Foote

 */

public abstract class Reader {

    protected PositionDataInputStream in;

    protected Reader(PositionDataInputStream in) {

        this.in = in;

    }

    /**

     * Read a snapshot from a data input stream.  It is assumed that the magic

     * number has already been read.

     */

    abstract public Snapshot read() throws IOException;

    /**

     * Read a snapshot from a file.

     *

     * @param heapFile The name of a file containing a heap dump

     * @param callStack If true, read the call stack of allocaation sites

     */

    public static Snapshot readFile(String heapFile, boolean callStack,

                                    int debugLevel)

            throws IOException {

        int dumpNumber = 1;

        int pos = heapFile.lastIndexOf('#');

        if (pos > -1) {

            String num = heapFile.substring(pos+1, heapFile.length());

            try {

                dumpNumber = Integer.parseInt(num, 10);

            } catch (java.lang.NumberFormatException ex) {

                String msg = "In file name \"" + heapFile

                             + "\", a dump number was "

                             + "expected after the :, but \""

                             + num + "\" was found instead.";

                System.err.println(msg);

                throw new IOException(msg);

            }

            heapFile = heapFile.substring(0, pos);

        }

        PositionDataInputStream in = new PositionDataInputStream(

            new BufferedInputStream(new FileInputStream(heapFile)));

        try {

            int i = in.readInt();

            if (i == HprofReader.MAGIC_NUMBER) {

                Reader r

                    = new HprofReader(heapFile, in, dumpNumber,

                                      callStack, debugLevel);

                return r.read();

            } else {

                throw new IOException("Unrecognized magic number: " + i);

            }

        } finally {

            in.close();

        }

    }

}