AndroidDigestFactory.java revision e6bf3e8dfa2804891a82075cb469b736321b4827 
1/*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package org.bouncycastle.crypto.digests;
18
19import org.bouncycastle.crypto.Digest;
20
21/**
22 * Level of indirection to let us select OpenSSLDigest implementations
23 * for libcore but fallback to BouncyCastle ones on the RI.
24 */
25public final class AndroidDigestFactory {
26    private static final String OpenSSLFactoryClassName
27            = AndroidDigestFactory.class.getName() + "OpenSSL";
28    private static final String BouncyCastleFactoryClassName
29            = AndroidDigestFactory.class.getName() + "BouncyCastle";
30
31    private static final AndroidDigestFactoryInterface FACTORY;
32    static {
33        Class factoryImplementationClass;
34        try {
35            factoryImplementationClass = Class.forName(OpenSSLFactoryClassName);
36        } catch (ClassNotFoundException e1) {
37            try {
38                factoryImplementationClass = Class.forName(BouncyCastleFactoryClassName);
39            } catch (ClassNotFoundException e2) {
40                throw new AssertionError("Failed to find AndroidDigestFactoryInterface "
41                                         + "implementation. Looked for "
42                                         + OpenSSLFactoryClassName + " and "
43                                         + BouncyCastleFactoryClassName);
44            }
45        }
46        if (!AndroidDigestFactoryInterface.class.isAssignableFrom(factoryImplementationClass)) {
47            throw new AssertionError(factoryImplementationClass
48                                     + "does not implement AndroidDigestFactoryInterface");
49        }
50        try {
51            FACTORY = (AndroidDigestFactoryInterface) factoryImplementationClass.newInstance();
52        } catch (InstantiationException e) {
53            throw new AssertionError(e);
54        } catch (IllegalAccessException e) {
55            throw new AssertionError(e);
56        }
57    }
58
59    public static Digest getMD5() {
60        return FACTORY.getMD5();
61    }
62
63    public static Digest getSHA1() {
64        return FACTORY.getSHA1();
65    }
66
67    public static Digest getSHA256() {
68        return FACTORY.getSHA256();
69    }
70
71    public static Digest getSHA384() {
72        return FACTORY.getSHA384();
73    }
74
75    public static Digest getSHA512() {
76        return FACTORY.getSHA512();
77    }
78}
79