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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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*/
/*
* @test
* @bug 4495754
* @summary Basic test for int bit twiddling
* @author Josh Bloch
*/
import java.util.Random;
import static java.lang.Integer.*;
public class BitTwiddle {
private static final int N = 1000; // # of repetitions per test
public static void main(String args[]) {
Random rnd = new Random();
if (highestOneBit(0) != 0)
throw new RuntimeException("a");
if (highestOneBit(-1) != MIN_VALUE)
throw new RuntimeException("b");
if (highestOneBit(1) != 1)
throw new RuntimeException("c");
if (lowestOneBit(0) != 0)
throw new RuntimeException("d");
if (lowestOneBit(-1) != 1)
throw new RuntimeException("e");
if (lowestOneBit(MIN_VALUE) != MIN_VALUE)
throw new RuntimeException("f");
for (int i = 0; i < N; i++) {
int x = rnd.nextInt();
if (highestOneBit(x) != reverse(lowestOneBit(reverse(x))))
throw new RuntimeException("g: " + toHexString(x));
}
if (numberOfLeadingZeros(0) != SIZE)
throw new RuntimeException("h");
if (numberOfLeadingZeros(-1) != 0)
throw new RuntimeException("i");
if (numberOfLeadingZeros(1) != (SIZE - 1))
throw new RuntimeException("j");
if (numberOfTrailingZeros(0) != SIZE)
throw new RuntimeException("k");
if (numberOfTrailingZeros(1) != 0)
throw new RuntimeException("l");
if (numberOfTrailingZeros(MIN_VALUE) != (SIZE - 1))
throw new RuntimeException("m");
for (int i = 0; i < N; i++) {
int x = rnd.nextInt();
if (numberOfLeadingZeros(x) != numberOfTrailingZeros(reverse(x)))
throw new RuntimeException("n: " + toHexString(x));
}
if (bitCount(0) != 0)
throw new RuntimeException("o");
for (int i = 0; i < SIZE; i++) {
int pow2 = 1 << i;
if (bitCount(pow2) != 1)
throw new RuntimeException("p: " + i);
if (bitCount(pow2 -1) != i)
throw new RuntimeException("q: " + i);
}
for (int i = 0; i < N; i++) {
int x = rnd.nextInt();
if (bitCount(x) != bitCount(reverse(x)))
throw new RuntimeException("r: " + toHexString(x));
}
for (int i = 0; i < N; i++) {
int x = rnd.nextInt();
int dist = rnd.nextInt();
if (bitCount(x) != bitCount(rotateRight(x, dist)))
throw new RuntimeException("s: " + toHexString(x) +
toHexString(dist));
if (bitCount(x) != bitCount(rotateLeft(x, dist)))
throw new RuntimeException("t: " + toHexString(x) +
toHexString(dist));
if (rotateRight(x, dist) != rotateLeft(x, -dist))
throw new RuntimeException("u: " + toHexString(x) +
toHexString(dist));
if (rotateRight(x, -dist) != rotateLeft(x, dist))
throw new RuntimeException("v: " + toHexString(x) +
toHexString(dist));
}
if (signum(0) != 0 || signum(1) != 1 || signum(-1) != -1
|| signum(MIN_VALUE) != -1 || signum(MAX_VALUE) != 1)
throw new RuntimeException("w");
for (int i = 0; i < N; i++) {
int x = rnd.nextInt();
int sign = (x < 0 ? -1 : (x == 0 ? 0 : 1));
if (signum(x) != sign)
throw new RuntimeException("x: " + toHexString(x));
}
if(reverseBytes(0xaabbccdd) != 0xddccbbaa)
throw new RuntimeException("y");
for (int i = 0; i < N; i++) {
int x = rnd.nextInt();
if (bitCount(x) != bitCount(reverseBytes(x)))
throw new RuntimeException("z: " + toHexString(x));
}
}
}