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/*
* 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
* @key randomness
*/
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);}}
}
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