/*

 * Copyright (c) 1997, 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.

 *

 * 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.

 */

/* @test

   @bug 4016710

   @summary check for correct implementation of InputStream.skip

   */

import java.io.*;

public class Skip{

    private static void dotest(InputStream in , int curpos ,

                               long total , long toskip , long expected)

        throws Exception

    {

        try {

            System.err.println("\n\nCurrently at pos = " + curpos +

                               "\nTotal bytes in the Stream = " + total +

                               "\nNumber of bytes to skip = " + toskip +

                               "\nNumber of bytes that should be skipped = " +

                               expected);

            long skipped = in.skip(toskip);

            System.err.println("actual number skipped: "+ skipped);

            if ((skipped < 0) || (skipped > expected)) {

                throw new RuntimeException("Unexpected number of bytes skipped");

            }

        } catch (IOException e) {

            System.err.println("IOException is thrown - possible result");

        } catch (Throwable e) {

            throw new RuntimeException("Unexpected "+e+" is thrown!");

        }

    }

    public static void main( String argv[] ) throws Exception {

        MyInputStream in = new MyInputStream(11);

        /* test for negative skip */

        dotest(in,  0, 11, -23,  0);

        /* check for skip beyond EOF starting from before EOF */

        dotest(in,  0, 11,  20, 11);

        /* check for skip after EOF */

        dotest(in, -1, 11,  20,  0);

        in = new MyInputStream(9000);

        /* check for skip equal to the read chunk size in InputStream.java */

        dotest(in,  0, 9000, 2048, 2048);

        /* check for skip greater than the read chunk size in InputStream.java */

        dotest(in, 2048, 9000, 5000, 5000);

        /* check for skip beyond EOF starting from before EOF */

        dotest(in, 7048, 9000, 5000, 1952);

        in = new MyInputStream(5000);

        /* check for multiple chunk reads */

        dotest(in, 0, 5000, 6000, 5000);

        /*

         * check for skip larger than Integer.MAX_VALUE

         * (Takes about 2 hrs on a sparc ultra-1)

         * long total = (long)Integer.MAX_VALUE + (long)10;

         * long toskip = total - (long)6;

         * in = new MyInputStream(total);

         * dotest(in, 0, total, toskip, toskip);

         */

    }

}

class MyInputStream extends InputStream {

    private int readctr = 0;

    private long endoffile;

    public MyInputStream(long endoffile) {

        this.endoffile = endoffile;

    }

    public int read() {

        if (readctr == endoffile) {

            return -1;

        }

        else {

            readctr++;

            return 0;

        }

    }

    public int available() { return 0; }

}