org.obm.push.protocol.data.TZDecoder.java Source code

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Here is the source code for org.obm.push.protocol.data.TZDecoder.java

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/* ***** BEGIN LICENSE BLOCK *****
 * 
 * Copyright (C) 2011-2014  Linagora
 *
 * This program is free software: you can redistribute it and/or 
 * modify it under the terms of the GNU Affero General Public License as 
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version, provided you comply 
 * with the Additional Terms applicable for OBM connector by Linagora 
 * pursuant to Section 7 of the GNU Affero General Public License, 
 * subsections (b), (c), and (e), pursuant to which you must notably (i) retain 
 * the Message sent thanks to OBM, Free Communication by Linagora? 
 * signature notice appended to any and all outbound messages 
 * (notably e-mail and meeting requests), (ii) retain all hypertext links between 
 * OBM and obm.org, as well as between Linagora and linagora.com, and (iii) refrain 
 * from infringing Linagora intellectual property rights over its trademarks 
 * and commercial brands. Other Additional Terms apply, 
 * see <http://www.linagora.com/licenses/> for more details. 
 *
 * This program is distributed in the hope that it will be useful, 
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License 
 * for more details. 
 *
 * You should have received a copy of the GNU Affero General Public License 
 * and its applicable Additional Terms for OBM along with this program. If not, 
 * see <http://www.gnu.org/licenses/> for the GNU Affero General Public License version 3 
 * and <http://www.linagora.com/licenses/> for the Additional Terms applicable to 
 * OBM connectors. 
 * 
 * ***** END LICENSE BLOCK ***** */
package org.obm.push.protocol.data;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.TimeZone;

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

public class TZDecoder {

    public TimeZone decode(String b64) {
        // Doc : [MS-ASDTYPE] 2.7 TimeZone
        // Doc about types :
        // http://msdn.microsoft.com/fr-fr/library/bb469811.aspx
        // 1 LONG = 4 bytes
        // 1 WCHAR = 2 bytes
        // 1 SYSTEMTIME = 8 SHORT = 8 X 2 bytes
        // TOTAL TIMEZONE STRUCT must be 172 bytes

        byte tzstruct[] = Base64.decodeBase64(b64);

        ByteBuffer bfBias = ByteBuffer.wrap(tzstruct, 0, 4);
        // NOT YET USED
        //
        // ByteBuffer bfStandardName = ByteBuffer.wrap(tzstruct, 4, 64);
        // ByteBuffer bfStandardDate = ByteBuffer.wrap(tzstruct, 68, 16);
        // ByteBuffer bfStandardBias = ByteBuffer.wrap(tzstruct, 84, 4);
        // ByteBuffer bfDaylightName = ByteBuffer.wrap(tzstruct, 88, 64);
        // ByteBuffer bfDaylightDate = ByteBuffer.wrap(tzstruct, 152, 16);
        // ByteBuffer bfDaylightBias = ByteBuffer.wrap(tzstruct, 168, 4);

        bfBias.order(ByteOrder.LITTLE_ENDIAN);
        int bias = bfBias.getInt(); // Java integer is 4-bytes-long

        // NOT YET USED
        //
        // bfStandardBias.order(ByteOrder.LITTLE_ENDIAN);
        // int standardBias = bfStandardBias.getInt();
        //      
        // bfDaylightBias.order(ByteOrder.LITTLE_ENDIAN);
        // int daylightBias = bfDaylightBias.getInt();

        TimeZone timezone = TimeZone.getDefault();
        timezone.setRawOffset(bias * 60 * 1000);

        String timezones[] = TimeZone.getAvailableIDs(bias * 60 * 1000);
        if (timezones.length > 0) {
            timezone = TimeZone.getTimeZone(timezones[0]);
        }

        // USEFUL DEBUG LINES
        //
        // StringBuffer sb = new StringBuffer();
        // for (int i = 0; i < 172; i+=1) {
        // sb.append(Byte.valueOf(tzstruct[i]).intValue());
        // }
        //      
        // logger.info("b64: " + b64);
        // logger.info("tzstruct: "+ sb.toString());
        // logger.info("bias: " + bias);
        // logger.info("standardbias: " + standardBias);
        // logger.info("standardname: " +
        // bfStandardName.asCharBuffer().toString());
        // logger.info("daylightBias: " + daylightBias);

        return timezone;
    }

}