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
31 import java.util.*;
32
33 public 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 }