1/*
2 * Copyright (c) 2007, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24/*
25 * @test
26 * @bug 6410729 6586631
27 * @summary Test previousClearBit, previousSetBit
28 * @key randomness
29 */
30
31import java.util.*;
32
33public class PreviousBits {
34
35    void testHashCode(final BitSet s) {
36        long h = 1234;
37        long[] words = s.toLongArray();
38        for (int i = words.length; --i >= 0; )
39            h ^= words[i] * (i + 1);
40        equal((int)((h >> 32) ^ h), s.hashCode());
41    }
42
43    void testOutOfBounds(final BitSet s) {
44        THROWS(IndexOutOfBoundsException.class,
45               new F(){void f(){ s.previousSetBit(-2);}},
46               new F(){void f(){ s.previousClearBit(-2);}},
47               new F(){void f(){ s.previousSetBit(Integer.MIN_VALUE);}},
48               new F(){void f(){ s.previousClearBit(Integer.MIN_VALUE);}},
49               new F(){void f(){ s.nextSetBit(-1);}},
50               new F(){void f(){ s.nextClearBit(-1);}},
51               new F(){void f(){ s.nextSetBit(Integer.MIN_VALUE);}},
52               new F(){void f(){ s.nextClearBit(Integer.MIN_VALUE);}});
53    }
54
55    void test(String[] args) throws Throwable {
56        final BitSet s = new BitSet();
57
58        // Test empty bitset
59        testOutOfBounds(s);
60        testHashCode(s);
61
62        for (int i = -1; i < 93;) {
63            equal(-1, s.previousSetBit(i));
64            equal( i, s.previousClearBit(i));
65            i++;
66            equal(-1, s.nextSetBit(i));
67            equal( i, s.nextClearBit(i));
68        }
69
70        // Test "singleton" bitsets
71        for (int j = 0; j < 161; j++) {
72            s.clear();
73            s.set(j);
74            testOutOfBounds(s);
75            testHashCode(s);
76
77            for (int i = -1; i < j; i++) {
78                equal(-1, s.previousSetBit(i));
79                equal( i, s.previousClearBit(i));
80                if (i >= 0) {
81                    equal(j, s.nextSetBit(i));
82                    equal(i, s.nextClearBit(i));
83                }
84            }
85
86            equal(j,   s.previousSetBit(j));
87            equal(j-1, s.previousClearBit(j));
88            equal(j,   s.nextSetBit(j));
89            equal(j+1, s.nextClearBit(j));
90
91            for (int i = j+1; i < j+100; i++) {
92                equal(j, s.previousSetBit(i));
93                equal(i, s.previousClearBit(i));
94                equal(-1, s.nextSetBit(i));
95                equal(i, s.nextClearBit(i));
96            }
97        }
98
99        // set even bits
100        s.clear();
101        for (int i = 0; i <= 128; i+=2)
102            s.set(i);
103        testHashCode(s);
104        for (int i = 1; i <= 128; i++) {
105            equal(s.previousSetBit(i),
106                  ((i & 1) == 0) ? i : i - 1);
107            equal(s.previousClearBit(i),
108                  ((i & 1) == 0) ? i - 1 : i);
109        }
110
111        // set odd bits as well
112        for (int i = 1; i <= 128; i+=2)
113            s.set(i);
114        testHashCode(s);
115        for (int i = 1; i <= 128; i++) {
116            equal(s.previousSetBit(i), i);
117            equal(s.previousClearBit(i), -1);
118        }
119
120        // Test loops documented in javadoc
121        Random rnd = new Random();
122        s.clear();
123        for (int i = 0; i < 10; i++)
124            s.set(rnd.nextInt(1066));
125        List<Integer> down = new ArrayList<Integer>();
126        for (int i = s.length(); (i = s.previousSetBit(i-1)) >= 0; )
127            down.add(i);
128        List<Integer> up = new ArrayList<Integer>();
129        for (int i = s.nextSetBit(0); i >= 0; i = s.nextSetBit(i+1))
130            up.add(i);
131        Collections.reverse(up);
132        equal(up, down);
133    }
134
135    //--------------------- Infrastructure ---------------------------
136    volatile int passed = 0, failed = 0;
137    void pass() {passed++;}
138    void fail() {failed++; Thread.dumpStack();}
139    void fail(String msg) {System.err.println(msg); fail();}
140    void unexpected(Throwable t) {failed++; t.printStackTrace();}
141    void check(boolean cond) {if (cond) pass(); else fail();}
142    void equal(Object x, Object y) {
143        if (x == null ? y == null : x.equals(y)) pass();
144        else fail(x + " not equal to " + y);}
145    public static void main(String[] args) throws Throwable {
146        new PreviousBits().instanceMain(args);}
147    void instanceMain(String[] args) throws Throwable {
148        try {test(args);} catch (Throwable t) {unexpected(t);}
149        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
150        if (failed > 0) throw new AssertionError("Some tests failed");}
151    abstract class F {abstract void f() throws Throwable;}
152    void THROWS(Class<? extends Throwable> k, F... fs) {
153        for (F f : fs)
154            try {f.f(); fail("Expected " + k.getName() + " not thrown");}
155            catch (Throwable t) {
156                if (k.isAssignableFrom(t.getClass())) pass();
157                else unexpected(t);}}
158}
159