org.mozilla.android.sync.crypto.Utils.java Source code

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Here is the source code for org.mozilla.android.sync.crypto.Utils.java

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/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Android Sync Client.
 *
 * The Initial Developer of the Original Code is
 * the Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2011
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 * Jason Voll
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

package org.mozilla.android.sync.crypto;

import java.io.UnsupportedEncodingException;
import java.util.Arrays;

import org.apache.commons.codec.binary.Base32;
import org.apache.commons.codec.binary.Base64;

public class Utils {

    /**
     * Helper to convert Hex String to Byte Array
     *
     * @param str a HEX string
     * @return byte[] version of hex string
     */
    public static byte[] hex2Byte(String str) {
        if (str.length() % 2 == 1) {
            str = "0" + str;
        }

        byte[] bytes = new byte[str.length() / 2];
        for (int i = 0; i < bytes.length; i++) {
            bytes[i] = (byte) Integer.parseInt(str.substring(2 * i, 2 * i + 2), 16);
        }
        return bytes;
    }

    /**
     * Helper to convert Byte Array to a Hex String
     *
     * @param b A byte array
     * @return Hex string
     */
    public static String byte2hex(byte[] b) {
        // String Buffer can be used instead
        String hs = "";
        String stmp;

        for (int n = 0; n < b.length; n++) {
            stmp = java.lang.Integer.toHexString(b[n] & 0XFF);

            if (stmp.length() == 1) {
                hs = hs + "0" + stmp;
            } else {
                hs = hs + stmp;
            }

            if (n < b.length - 1) {
                hs = hs + "";
            }
        }

        return hs;
    }

    /**
     * Helper for array concatenation.
     *
     * @param first first byte array
     * @param rest  at least one byte array
     * @return A concatenated version of all byte arrays
     */
    public static byte[] concatAll(byte[] first, byte[]... rest) {
        int totalLength = first.length;
        for (byte[] array : rest) {
            totalLength += array.length;
        }

        byte[] result = Arrays.copyOf(first, totalLength);
        int offset = first.length;

        for (byte[] array : rest) {
            System.arraycopy(array, 0, result, offset, array.length);
            offset += array.length;
        }
        return result;
    }

    /**
     * Decode a friendly base32 string.
     * see http://docs.services.mozilla.com/sync/storageformat5.html#the-sync-key
     *
     * @param base32 a friendly base32 string
     * @return the bytes of the encoded string
     */
    public static byte[] decodeFriendlyBase32(String base32) {
        Base32 converter = new Base32();
        return converter.decode(base32.replace('8', 'l').replace('9', 'o').replaceAll("-", "").toUpperCase());
    }

    /**
     * Utility for Base64 decoding. Should ensure that the correct
     * Apache Commons version is used.
     *
     * @param base64 An input string. Will be decoded as UTF-8.
     * @return A byte array of decoded values.
     * @throws UnsupportedEncodingException Should not occur.
     */
    public static byte[] decodeBase64(String base64) throws UnsupportedEncodingException {
        return Base64.decodeBase64(base64.getBytes("UTF-8"));
    }
}