/*

 * Copyright (c) 2001, 2010, 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

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 * questions.

 */

/* @test

   @bug 4452020 4629048 4638365 4869859

 * @summary Test FileChannel scattering reads

 * @run main/othervm ScatteringRead

 */

import java.nio.channels.*;

import java.nio.*;

import java.io.*;

public class ScatteringRead {

    private static final int NUM_BUFFERS = 3;

    private static final int BUFFER_CAP = 3;

    private static final int BIG_BUFFER_CAP = Integer.MAX_VALUE / 3 + 10;

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

        test1(); // for bug 4452020

        test2(); // for bug 4629048

        System.gc();

        // Test 3 proves that the system is capable of reading

        // more than MAX_INT bytes in one shot. But it is unsuitable

        // for automated testing because oftentimes less bytes are

        // read for various reasons, and this is allowed by the spec.

        // test3(); // for bug 4638365

    }

    private static void test1() throws Exception {

        ByteBuffer dstBuffers[] = new ByteBuffer[NUM_BUFFERS];

        for (int i=0; i<NUM_BUFFERS; i++)

            dstBuffers[i] = ByteBuffer.allocateDirect(BUFFER_CAP);

        File blah = File.createTempFile("blah1", null);

        blah.deleteOnExit();

        createTestFile(blah);

        FileInputStream fis = new FileInputStream(blah);

        FileChannel fc = fis.getChannel();

        byte expectedResult = -128;

        for (int k=0; k<20; k++) {

            long bytesRead = fc.read(dstBuffers);

            for (int i=0; i<NUM_BUFFERS; i++) {

                for (int j=0; j<BUFFER_CAP; j++) {

                    byte b = dstBuffers[i].get(j);

                    if (b != expectedResult++)

                        throw new RuntimeException("Test failed");

                }

                dstBuffers[i].flip();

            }

        }

        fis.close();

    }

    private static void createTestFile(File blah) throws Exception {

        FileOutputStream fos = new FileOutputStream(blah);

        for(int i=-128; i<128; i++)

            fos.write((byte)i);

        fos.flush();

        fos.close();

    }

    private static void test2() throws Exception {

        ByteBuffer dstBuffers[] = new ByteBuffer[2];

        for (int i=0; i<2; i++)

            dstBuffers[i] = ByteBuffer.allocateDirect(10);

        File blah = File.createTempFile("blah2", null);

        blah.deleteOnExit();

        FileOutputStream fos = new FileOutputStream(blah);

        for(int i=0; i<15; i++)

            fos.write((byte)92);

        fos.flush();

        fos.close();

        FileInputStream fis = new FileInputStream(blah);

        FileChannel fc = fis.getChannel();

        long bytesRead = fc.read(dstBuffers);

        if (dstBuffers[1].limit() != 10)

            throw new Exception("Scattering read changed buf limit.");

        fis.close();

    }

    private static void test3() throws Exception {

        // Only works on 64 bit Solaris

        String osName = System.getProperty("os.name");

        if (!osName.startsWith("SunOS"))

            return;

        String dataModel = System.getProperty("sun.arch.data.model");

        if (!dataModel.startsWith("64"))

            return;

        ByteBuffer dstBuffers[] = new ByteBuffer[NUM_BUFFERS];

        File f = File.createTempFile("test3", null);

        f.deleteOnExit();

        prepTest3File(f, (long)BIG_BUFFER_CAP);

        RandomAccessFile raf = new RandomAccessFile(f, "rw");

        FileChannel fc = raf.getChannel();

        MappedByteBuffer mbb = fc.map(FileChannel.MapMode.READ_WRITE, 0,

                                      BIG_BUFFER_CAP);

        for (int i=0; i<NUM_BUFFERS; i++) {

            dstBuffers[i] = mbb;

        }

        fc.close();

        raf.close();

        // Source must be large

        FileInputStream fis = new FileInputStream("/dev/zero");

        fc = fis.getChannel();

        long bytesRead = fc.read(dstBuffers);

        if (bytesRead <= Integer.MAX_VALUE)

            throw new RuntimeException("Test 3 failed "+bytesRead+" < "+Integer.MAX_VALUE);

        fc.close();

        fis.close();

    }

    static void prepTest3File(File blah, long testSize) throws Exception {

        RandomAccessFile raf = new RandomAccessFile(blah, "rw");

        FileChannel fc = raf.getChannel();

        fc.write(ByteBuffer.wrap("Use the source!".getBytes()), testSize - 40);

        fc.close();

        raf.close();

    }

}