Flush.java

/*
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 * 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.
 *
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 */

/* @test
 * @bug 6227608
 * @summary Test proper handling of flush()
 * @author Martin Buchholz
 */

import java.util.*;
import java.io.*;
import java.nio.*;
import java.nio.charset.*;

public class Flush {
    private static byte[] contents(ByteBuffer bb) {
        byte[] contents = new byte[bb.position()];
        ((ByteBuffer)(bb.duplicate().flip())).get(contents);
        return contents;
    }

    private static ByteBuffer extend(ByteBuffer bb) {
        ByteBuffer x = ByteBuffer.allocate(2*bb.capacity()+10);
        bb.flip();
        x.put(bb);
        return x;
    }

    private static void realMain(String[] args) throws Throwable {
        // A japanese character should decode as a 3-byte
        // switch-to-japanese escape sequence, followed by a 2-byte
        // encoding of the char itself, followed by a 3-byte return to
        // ASCII escape sequence.
        char[] jis0208 = {'\u3001'};
        CharBuffer cb = CharBuffer.wrap(jis0208);
        ByteBuffer bb = ByteBuffer.allocate(6);
        CharsetEncoder enc = Charset.forName("ISO-2022-JP").newEncoder();

        check(enc.encode(cb, bb, true).isUnderflow());

        System.out.println(Arrays.toString(contents(bb)));
        check(! cb.hasRemaining());
        equal(contents(bb).length, 3 + 2);
        equal(bb.get(0), (byte)0x1b);

        //----------------------------------------------------------------
        // We must be able to recover if flush() returns OVERFLOW
        //----------------------------------------------------------------
        check(enc.flush(bb).isOverflow());
        check(enc.flush(bb).isOverflow());
        equal(contents(bb).length, 3 + 2);

        bb = extend(bb);

        check(enc.flush(bb).isUnderflow());
        equal(bb.get(3 + 2), (byte)0x1b);
        System.out.println(Arrays.toString(contents(bb)));
        equal(contents(bb).length, 3 + 2 + 3);

        //----------------------------------------------------------------
        // A final redundant flush() is a no-op
        //----------------------------------------------------------------
        check(enc.flush(bb).isUnderflow());
        check(enc.flush(bb).isUnderflow());
        equal(contents(bb).length, 3 + 2 + 3);

        //----------------------------------------------------------------
        // CharsetEncoder.encode(ByteBuffer) must call flush(ByteBuffer)
        //----------------------------------------------------------------
        bb = enc.encode(CharBuffer.wrap(jis0208));
        byte[] expected = "\u001b$B!\"\u001b(B".getBytes("ASCII");
        byte[] contents = new byte[bb.limit()]; bb.get(contents);
        check(Arrays.equals(contents, expected));
    }

    //--------------------- Infrastructure ---------------------------
    static volatile int passed = 0, failed = 0;
    static void pass() { passed++; }
    static void fail() { failed++; Thread.dumpStack(); }
    static void fail(String msg) { System.out.println(msg); fail(); }
    static void unexpected(Throwable t) { failed++; t.printStackTrace(); }
    static void check(boolean cond) { if (cond) pass(); else fail(); }
    static void equal(Object x, Object y) {
        if (x == null ? y == null : x.equals(y)) pass();
        else {System.out.println(x + " not equal to " + y); fail(); }}

    public static void main(String[] args) throws Throwable {
        try { realMain(args); } catch (Throwable t) { unexpected(t); }

        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
        if (failed > 0) throw new Exception("Some tests failed");
    }
}