1/*
2 * Copyright (c) 2003, 2015, 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
26package sun.security.jca;
27
28import java.lang.ref.*;
29
30import 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 */
38public final class JCAUtil {
39
40    private JCAUtil() {
41        // no instantiation
42    }
43
44    // size of the temporary arrays we use. Should fit into the CPU's 1st
45    // level cache and could be adjusted based on the platform
46    private static final int ARRAY_SIZE = 4096;
47
48    /**
49     * Get the size of a temporary buffer array to use in order to be
50     * cache efficient. totalSize indicates the total amount of data to
51     * be buffered. Used by the engineUpdate(ByteBuffer) methods.
52     */
53    public static int getTempArraySize(int totalSize) {
54        return Math.min(ARRAY_SIZE, totalSize);
55    }
56
57    // cached SecureRandom instance
58    private static class CachedSecureRandomHolder {
59        public static SecureRandom instance = new SecureRandom();
60    }
61
62    /**
63     * Get a SecureRandom instance. This method should be used by JDK
64     * internal code in favor of calling "new SecureRandom()". That needs to
65     * iterate through the provider table to find the default SecureRandom
66     * implementation, which is fairly inefficient.
67     */
68    public static SecureRandom getSecureRandom() {
69        return CachedSecureRandomHolder.instance;
70    }
71
72}
73