001/*
002 * The contents of this file are subject to the terms of the Common Development and
003 * Distribution License (the License). You may not use this file except in compliance with the
004 * License.
005 *
006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
007 * specific language governing permission and limitations under the License.
008 *
009 * When distributing Covered Software, include this CDDL Header Notice in each file and include
010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
011 * Header, with the fields enclosed by brackets [] replaced by your own identifying
012 * information: "Portions copyright [year] [name of copyright owner]".
013 *
014 * Copyright 2015-2016 ForgeRock AS.
015 */
016
017package org.forgerock.util.encode;
018
019/**
020 * Makes use of the very fast and memory efficient Base64 class to encode and
021 * decode to and from BASE64 in full accordance with RFC 2045. And then replaces
022 * + and / for - and _ respectively and removes the padding character = to be in
023 * accordance with RFC 4648.
024 */
025public final class Base64url {
026    /**
027     * Decodes the given Base64url encoded String into a byte array.
028     *
029     * @param content
030     *            The Base64url encoded String to decode.
031     * @return The decoded byte[] array.
032     */
033    public static byte[] decode(final String content) {
034        final StringBuilder builder =
035                new StringBuilder(content.replaceAll("-", "+").replaceAll("_", "/"));
036        final int modulus = builder.length() % 4;
037        final int numberOfPaddingChars = 4 - modulus;
038        if (modulus != 0) {
039            for (int i = 0; i < numberOfPaddingChars; i++) {
040                builder.append('=');
041            }
042        }
043        return Base64.decode(builder.toString());
044    }
045
046    /**
047     * Encodes the given byte array into a Base64url encoded String.
048     *
049     * @param content
050     *            The byte array to encode.
051     * @return The Base64url encoded byte array.
052     */
053    public static String encode(final byte[] content) {
054        return Base64.encode(content).replaceAll("\\+", "-").replaceAll("/", "_").replaceAll("=",
055                "");
056    }
057
058    private Base64url() {
059        // No impl.
060    }
061}