jdk/test/java/util/BitSet/PreviousBits.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/util/BitSet/PreviousBits.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,157 @@
+/*
+ * Copyright 2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.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);}}
+}