/*

 * Copyright (c) 1998, 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 4090383

   @summary Ensure that BufferedReader's read method will fill the target array

            whenever possible

 */

import java.io.IOException;

import java.io.Reader;

import java.io.BufferedReader;

public class Fill {

    /**

     * A simple Reader that is always ready but may read fewer than the

     * requested number of characters

     */

    static class Source extends Reader {

        int shortFall;

        char next = 0;

        Source(int shortFall) {

            this.shortFall = shortFall;

        }

        public int read(char[] cbuf, int off, int len) throws IOException {

            int n = len - shortFall;

            for (int i = off; i < n; i++)

                cbuf[i] = next++;

            return n;

        }

        public boolean ready() {

            return true;

        }

        public void close() throws IOException {

        }

    }

    /**

     * Test BufferedReader with an underlying source that always reads

     * shortFall fewer characters than requested

     */

    static void go(int shortFall) throws Exception {

        Reader r = new BufferedReader(new Source(shortFall), 10);

        char[] cbuf = new char[8];

        int n1 = r.read(cbuf);

        int n2 = r.read(cbuf);

        System.err.println("Shortfall " + shortFall

                           + ": Read " + n1 + ", then " + n2 + " chars");

        if (n1 != cbuf.length)

            throw new Exception("First read returned " + n1);

        if (n2 != cbuf.length)

            throw new Exception("Second read returned " + n2);

    }

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

        for (int i = 0; i < 8; i++) go(i);

    }

}