/*

 * Copyright (c) 2007, 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 6410729 6586631

 * @summary Test previousClearBit, previousSetBit

 */

import java.util.*;

public class PreviousBits {

    void testHashCode(final BitSet s) {

        long h = 1234;

        long[] words = s.toLongArray();

        for (int i = words.length; --i >= 0; )

            h ^= words[i] * (i + 1);

        equal((int)((h >> 32) ^ h), s.hashCode());

    }

    void testOutOfBounds(final BitSet s) {

        THROWS(IndexOutOfBoundsException.class,

               new F(){void f(){ s.previousSetBit(-2);}},

               new F(){void f(){ s.previousClearBit(-2);}},

               new F(){void f(){ s.previousSetBit(Integer.MIN_VALUE);}},

               new F(){void f(){ s.previousClearBit(Integer.MIN_VALUE);}},

               new F(){void f(){ s.nextSetBit(-1);}},

               new F(){void f(){ s.nextClearBit(-1);}},

               new F(){void f(){ s.nextSetBit(Integer.MIN_VALUE);}},

               new F(){void f(){ s.nextClearBit(Integer.MIN_VALUE);}});

    }

    void test(String[] args) throws Throwable {

        final BitSet s = new BitSet();

        // Test empty bitset

        testOutOfBounds(s);

        testHashCode(s);

        for (int i = -1; i < 93;) {

            equal(-1, s.previousSetBit(i));

            equal( i, s.previousClearBit(i));

            i++;

            equal(-1, s.nextSetBit(i));

            equal( i, s.nextClearBit(i));

        }

        // Test "singleton" bitsets

        for (int j = 0; j < 161; j++) {

            s.clear();

            s.set(j);

            testOutOfBounds(s);

            testHashCode(s);

            for (int i = -1; i < j; i++) {

                equal(-1, s.previousSetBit(i));

                equal( i, s.previousClearBit(i));

                if (i >= 0) {

                    equal(j, s.nextSetBit(i));

                    equal(i, s.nextClearBit(i));

                }

            }

            equal(j,   s.previousSetBit(j));

            equal(j-1, s.previousClearBit(j));

            equal(j,   s.nextSetBit(j));

            equal(j+1, s.nextClearBit(j));

            for (int i = j+1; i < j+100; i++) {

                equal(j, s.previousSetBit(i));

                equal(i, s.previousClearBit(i));

                equal(-1, s.nextSetBit(i));

                equal(i, s.nextClearBit(i));

            }

        }

        // set even bits

        s.clear();

        for (int i = 0; i <= 128; i+=2)

            s.set(i);

        testHashCode(s);

        for (int i = 1; i <= 128; i++) {

            equal(s.previousSetBit(i),

                  ((i & 1) == 0) ? i : i - 1);

            equal(s.previousClearBit(i),

                  ((i & 1) == 0) ? i - 1 : i);

        }

        // set odd bits as well

        for (int i = 1; i <= 128; i+=2)

            s.set(i);

        testHashCode(s);

        for (int i = 1; i <= 128; i++) {

            equal(s.previousSetBit(i), i);

            equal(s.previousClearBit(i), -1);

        }

        // Test loops documented in javadoc

        Random rnd = new Random();

        s.clear();

        for (int i = 0; i < 10; i++)

            s.set(rnd.nextInt(1066));

        List<Integer> down = new ArrayList<Integer>();

        for (int i = s.length(); (i = s.previousSetBit(i-1)) >= 0; )

            down.add(i);

        List<Integer> up = new ArrayList<Integer>();

        for (int i = s.nextSetBit(0); i >= 0; i = s.nextSetBit(i+1))

            up.add(i);

        Collections.reverse(up);

        equal(up, down);

    }

    //--------------------- Infrastructure ---------------------------

    volatile int passed = 0, failed = 0;

    void pass() {passed++;}

    void fail() {failed++; Thread.dumpStack();}

    void fail(String msg) {System.err.println(msg); fail();}

    void unexpected(Throwable t) {failed++; t.printStackTrace();}

    void check(boolean cond) {if (cond) pass(); else fail();}

    void equal(Object x, Object y) {

        if (x == null ? y == null : x.equals(y)) pass();

        else fail(x + " not equal to " + y);}

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

        new PreviousBits().instanceMain(args);}

    void instanceMain(String[] args) throws Throwable {

        try {test(args);} catch (Throwable t) {unexpected(t);}

        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);

        if (failed > 0) throw new AssertionError("Some tests failed");}

    abstract class F {abstract void f() throws Throwable;}

    void THROWS(Class<? extends Throwable> k, F... fs) {

        for (F f : fs)

            try {f.f(); fail("Expected " + k.getName() + " not thrown");}

            catch (Throwable t) {

                if (k.isAssignableFrom(t.getClass())) pass();

                else unexpected(t);}}

}