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| 1 | /* | ||
| 2 | * Copyright (c) 2003, 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. Oracle designates this | ||
| 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 sun.security.jca; | ||
| 27 | |||
| 28 | import java.lang.ref.*; | ||
| 29 | |||
| 30 | import java.security.*; | ||
| 31 | |||
| 32 | /** | ||
| 33 | * Collection of static utility methods used by the security framework. | ||
| 34 | * | ||
| 35 | * @author Andreas Sterbenz | ||
| 36 | * @since 1.5 | ||
| 37 | */ | ||
| 38 | public final class JCAUtil { | ||
| 39 | |||
| 40 | private JCAUtil() { | ||
| 41 | // no instantiation | ||
| 42 | } | ||
| 43 | |||
| 44 | // lock to use for synchronization | ||
| 45 | private static final Object LOCK = JCAUtil.class; | ||
| 46 | |||
| 47 | // cached SecureRandom instance | ||
| 48 | private static volatile SecureRandom secureRandom; | ||
| 49 | |||
| 50 | // size of the temporary arrays we use. Should fit into the CPU's 1st | ||
| 51 | // level cache and could be adjusted based on the platform | ||
| 52 | private final static int ARRAY_SIZE = 4096; | ||
| 53 | |||
| 54 | /** | ||
| 55 | * Get the size of a temporary buffer array to use in order to be | ||
| 56 | * cache efficient. totalSize indicates the total amount of data to | ||
| 57 | * be buffered. Used by the engineUpdate(ByteBuffer) methods. | ||
| 58 | */ | ||
| 59 | public static int getTempArraySize(int totalSize) { | ||
| 60 | return Math.min(ARRAY_SIZE, totalSize); | ||
| 61 | } | ||
| 62 | |||
| 63 | /** | ||
| 64 | * Get a SecureRandom instance. This method should me used by JDK | ||
| 65 | * internal code in favor of calling "new SecureRandom()". That needs to | ||
| 66 | * iterate through the provider table to find the default SecureRandom | ||
| 67 | * implementation, which is fairly inefficient. | ||
| 68 | */ | ||
| 69 | public static SecureRandom getSecureRandom() { | ||
| 70 | // we use double checked locking to minimize synchronization | ||
| 71 | // works because we use a volatile reference | ||
| 72 | SecureRandom r = secureRandom; | ||
| 73 | if (r == null) { | ||
| 74 | synchronized (LOCK) { | ||
| 75 | r = secureRandom; | ||
| 76 | if (r == null) { | ||
| 77 | r = new SecureRandom(); | ||
| 78 | secureRandom = r; | ||
| 79 | } | ||
| 80 | } | ||
| 81 | } | ||
| 82 | return r; | ||
| 83 | } | ||
| 84 | |||
| 85 | } | ||