| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.codec.digest; |
| |
| import java.security.SecureRandom; |
| import java.util.Random; |
| |
| /** |
| * Base64-like method to convert binary bytes into ASCII chars. |
| * <p> |
| * TODO: Can Base64 be reused? |
| * </p> |
| * <p> |
| * This class is immutable and thread-safe. |
| * </p> |
| * |
| * @since 1.7 |
| */ |
| class B64 { |
| |
| /** |
| * Table with characters for Base64 transformation. |
| */ |
| static final String B64T_STRING = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"; |
| |
| /** |
| * Table with characters for Base64 transformation. |
| */ |
| static final char[] B64T_ARRAY = B64T_STRING.toCharArray(); |
| |
| /** |
| * Base64 like conversion of bytes to ASCII chars. |
| * |
| * @param b2 |
| * A byte from the result. |
| * @param b1 |
| * A byte from the result. |
| * @param b0 |
| * A byte from the result. |
| * @param outLen |
| * The number of expected output chars. |
| * @param buffer |
| * Where the output chars is appended to. |
| */ |
| static void b64from24bit(final byte b2, final byte b1, final byte b0, final int outLen, |
| final StringBuilder buffer) { |
| // The bit masking is necessary because the JVM byte type is signed! |
| int w = ((b2 << 16) & 0x00ffffff) | ((b1 << 8) & 0x00ffff) | (b0 & 0xff); |
| // It's effectively a "for" loop but kept to resemble the original C code. |
| int n = outLen; |
| while (n-- > 0) { |
| buffer.append(B64T_ARRAY[w & 0x3f]); |
| w >>= 6; |
| } |
| } |
| |
| /** |
| * Generates a string of random chars from the B64T set. |
| * <p> |
| * The salt is generated with {@link SecureRandom}. |
| * </p> |
| * |
| * @param num Number of chars to generate. |
| * @return a random salt {@link String}. |
| */ |
| static String getRandomSalt(final int num) { |
| return getRandomSalt(num, new SecureRandom()); |
| } |
| |
| /** |
| * Generates a string of random chars from the B64T set. |
| * <p> |
| * The salt is generated with the {@link Random} provided. |
| * </p> |
| * |
| * @param num Number of chars to generate. |
| * @param random an instance of {@link Random}. |
| * @return a random salt {@link String}. |
| */ |
| static String getRandomSalt(final int num, final Random random) { |
| final StringBuilder saltString = new StringBuilder(num); |
| for (int i = 1; i <= num; i++) { |
| saltString.append(B64T_STRING.charAt(random.nextInt(B64T_STRING.length()))); |
| } |
| return saltString.toString(); |
| } |
| } |