/*

 * 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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import java.io.ByteArrayInputStream;

import java.io.FilterInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.util.Arrays;

import java.util.Random;

import jdk.test.lib.RandomFactory;

/*

 * @test

 * @library /test/lib

 * @build jdk.test.lib.RandomFactory

 * @run main ReadNBytes

 * @summary Basic test for InputStream.readNBytes

 * @key randomness

 */

public class ReadNBytes {

    private static Random generator = RandomFactory.getRandom();

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

        test(new byte[]{1, 2, 3});

        test(createRandomBytes(1024));

    }

    static void test(byte[] inputBytes) throws IOException {

        int length = inputBytes.length;

        WrapperInputStream in = new WrapperInputStream(new ByteArrayInputStream(inputBytes));

        byte[] readBytes = new byte[(length / 2) + 1];

        int nread = in.readNBytes(readBytes, 0, readBytes.length);

        int x;

        byte[] tmp;

        check(nread == readBytes.length,

              "Expected number of bytes read: " + readBytes.length + ", got: " + nread);

        check(Arrays.equals((tmp = Arrays.copyOf(inputBytes, nread)), readBytes),

              "Expected[" + tmp + "], got:[" + readBytes + "]");

        check(!in.isClosed(), "Stream unexpectedly closed");

        // Read again

        nread = in.readNBytes(readBytes, 0, readBytes.length);

        check(nread == length - readBytes.length,

              "Expected number of bytes read: " + (length - readBytes.length) + ", got: " + nread);

        check(Arrays.equals((tmp = Arrays.copyOfRange(inputBytes, readBytes.length, length)),

                            Arrays.copyOf(readBytes, nread)),

              "Expected[" + tmp + "], got:[" + readBytes + "]");

        // Expect end of stream

        check((x = in.read()) == -1,

              "Expected end of stream from read(), got " + x);

        check((x = in.read(tmp)) == -1,

              "Expected end of stream from read(byte[]), got " + x);

        check((x = in.read(tmp, 0, tmp.length)) == -1,

              "Expected end of stream from read(byte[], int, int), got " + x);

        check((x = in.readNBytes(tmp, 0, tmp.length)) == 0,

              "Expected end of stream, 0, from readNBytes(byte[], int, int), got " + x);

        check(!in.isClosed(), "Stream unexpectedly closed");

    }

    static byte[] createRandomBytes(int size) {

        byte[] bytes = new byte[size];

        generator.nextBytes(bytes);

        return bytes;

    }

    static void check(boolean cond, Object ... failedArgs) {

        if (cond)

            return;

        StringBuilder sb = new StringBuilder();

        for (Object o : failedArgs)

            sb.append(o);

        throw new RuntimeException(sb.toString());

    }

    static class WrapperInputStream extends FilterInputStream {

        private boolean closed;

        WrapperInputStream(InputStream in) { super(in); }

        @Override public void close() throws IOException { closed = true; in.close(); }

        boolean isClosed() { return closed; }

    }

}