8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util;
27
28 import java.net.NetworkInterface;
29 import java.util.concurrent.atomic.AtomicLong;
30 import java.util.function.IntConsumer;
31 import java.util.function.LongConsumer;
32 import java.util.function.DoubleConsumer;
33 import java.util.stream.StreamSupport;
34 import java.util.stream.IntStream;
35 import java.util.stream.LongStream;
36 import java.util.stream.DoubleStream;
37
38 /**
39 * A generator of uniform pseudorandom values applicable for use in
40 * (among other contexts) isolated parallel computations that may
41 * generate subtasks. Class {@code SplittableRandom} supports methods for
42 * producing pseudorandom numbers of type {@code int}, {@code long},
43 * and {@code double} with similar usages as for class
44 * {@link java.util.Random} but differs in the following ways:
45 *
46 * <ul>
47 *
48 * <li>Series of generated values pass the DieHarder suite testing
213 int n = Long.bitCount(z ^ (z >>> 1)); // ensure enough transitions
214 return (n < 24) ? z ^ 0xaaaaaaaaaaaaaaaaL : z;
215 }
216
217 /**
218 * Adds gamma to seed.
219 */
220 private long nextSeed() {
221 return seed += gamma;
222 }
223
224 /**
225 * The seed generator for default constructors.
226 */
227 private static final AtomicLong defaultGen = new AtomicLong(initialSeed());
228
229 private static long initialSeed() {
230 String pp = java.security.AccessController.doPrivileged(
231 new sun.security.action.GetPropertyAction(
232 "java.util.secureRandomSeed"));
233 if (pp != null && pp.equalsIgnoreCase("true")) {
234 byte[] seedBytes = java.security.SecureRandom.getSeed(8);
235 long s = (long)(seedBytes[0]) & 0xffL;
236 for (int i = 1; i < 8; ++i)
237 s = (s << 8) | ((long)(seedBytes[i]) & 0xffL);
238 return s;
239 }
240 long h = 0L;
241 try {
242 Enumeration<NetworkInterface> ifcs =
243 NetworkInterface.getNetworkInterfaces();
244 boolean retry = false; // retry once if getHardwareAddress is null
245 while (ifcs.hasMoreElements()) {
246 NetworkInterface ifc = ifcs.nextElement();
247 if (!ifc.isVirtual()) { // skip fake addresses
248 byte[] bs = ifc.getHardwareAddress();
249 if (bs != null) {
250 int n = bs.length;
251 int m = Math.min(n >>> 1, 4);
252 for (int i = 0; i < m; ++i)
253 h = (h << 16) ^ (bs[i] << 8) ^ bs[n-1-i];
254 if (m < 4)
255 h = (h << 8) ^ bs[n-1-m];
256 h = mix64(h);
257 break;
258 }
259 else if (!retry)
260 retry = true;
261 else
262 break;
263 }
264 }
265 } catch (Exception ignore) {
266 }
267 return (h ^ mix64(System.currentTimeMillis()) ^
268 mix64(System.nanoTime()));
|
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.util;
27
28 import sun.misc.JavaNetAccess;
29 import sun.misc.SharedSecrets;
30
31 import java.net.NetworkInterface;
32 import java.security.NoSuchAlgorithmException;
33 import java.security.NoSuchProviderException;
34 import java.security.SecureRandom;
35 import java.util.concurrent.atomic.AtomicLong;
36 import java.util.function.IntConsumer;
37 import java.util.function.LongConsumer;
38 import java.util.function.DoubleConsumer;
39 import java.util.stream.StreamSupport;
40 import java.util.stream.IntStream;
41 import java.util.stream.LongStream;
42 import java.util.stream.DoubleStream;
43
44 /**
45 * A generator of uniform pseudorandom values applicable for use in
46 * (among other contexts) isolated parallel computations that may
47 * generate subtasks. Class {@code SplittableRandom} supports methods for
48 * producing pseudorandom numbers of type {@code int}, {@code long},
49 * and {@code double} with similar usages as for class
50 * {@link java.util.Random} but differs in the following ways:
51 *
52 * <ul>
53 *
54 * <li>Series of generated values pass the DieHarder suite testing
219 int n = Long.bitCount(z ^ (z >>> 1)); // ensure enough transitions
220 return (n < 24) ? z ^ 0xaaaaaaaaaaaaaaaaL : z;
221 }
222
223 /**
224 * Adds gamma to seed.
225 */
226 private long nextSeed() {
227 return seed += gamma;
228 }
229
230 /**
231 * The seed generator for default constructors.
232 */
233 private static final AtomicLong defaultGen = new AtomicLong(initialSeed());
234
235 private static long initialSeed() {
236 String pp = java.security.AccessController.doPrivileged(
237 new sun.security.action.GetPropertyAction(
238 "java.util.secureRandomSeed"));
239 if (pp != null) {
240 SecureRandom sr;
241 if (pp.equalsIgnoreCase("true")) {
242 sr = new SecureRandom();
243 } else {
244 String[] args = pp.split(",", 2);
245 try {
246 sr = args.length > 1
247 ? SecureRandom.getInstance(args[0], args[1])
248 : SecureRandom.getInstance(args[0]);
249 } catch (NoSuchAlgorithmException | NoSuchProviderException e) {
250 throw new IllegalArgumentException(
251 "Invalid java.util.secureRandomSeed property: " + pp, e);
252 }
253 }
254 byte[] seedBytes = sr.generateSeed(8);
255 long s = (long)(seedBytes[0]) & 0xffL;
256 for (int i = 1; i < 8; ++i)
257 s = (s << 8) | ((long)(seedBytes[i]) & 0xffL);
258 return s;
259 }
260 long h = 0L;
261 try {
262 Enumeration<NetworkInterface> ifcs =
263 NetworkInterface.getNetworkInterfaces();
264 JavaNetAccess jna = SharedSecrets.getJavaNetAccess();
265 boolean retry = false; // retry once if getHardwareAddress is null
266 while (ifcs.hasMoreElements()) {
267 NetworkInterface ifc = ifcs.nextElement();
268 if (!ifc.isVirtual()) { // skip fake addresses
269 byte[] bs = jna.getHardwareAddress0(ifc);
270 if (bs != null) {
271 int n = bs.length;
272 int m = Math.min(n >>> 1, 4);
273 for (int i = 0; i < m; ++i)
274 h = (h << 16) ^ (bs[i] << 8) ^ bs[n-1-i];
275 if (m < 4)
276 h = (h << 8) ^ bs[n-1-m];
277 h = mix64(h);
278 break;
279 }
280 else if (!retry)
281 retry = true;
282 else
283 break;
284 }
285 }
286 } catch (Exception ignore) {
287 }
288 return (h ^ mix64(System.currentTimeMillis()) ^
289 mix64(System.nanoTime()));
|