es.rickyepoderi.wbxml.document.opaque.WVIntegerOpaque Maven / Gradle / Ivy

Go to download
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *    
 * Linking this library statically or dynamically with other modules 
 * is making a combined work based on this library. Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *    
 * As a special exception, the copyright holders of this library give 
 * you permission to link this library with independent modules to 
 * produce an executable, regardless of the license terms of these 
 * independent modules, and to copy and distribute the resulting 
 * executable under terms of your choice, provided that you also meet, 
 * for each linked independent module, the terms and conditions of the 
 * license of that module.  An independent module is a module which 
 * is not derived from or based on this library.  If you modify this 
 * library, you may extend this exception to your version of the 
 * library, but you are not obligated to do so.  If you do not wish 
 * to do so, delete this exception statement from your version.
 *
 * Project: github.com/rickyepoderi/wbxml-stream
 * 
 */
package es.rickyepoderi.wbxml.document.opaque;

import es.rickyepoderi.wbxml.document.OpaqueContentPlugin;
import es.rickyepoderi.wbxml.document.WbXmlContent;
import es.rickyepoderi.wbxml.document.WbXmlElement;
import es.rickyepoderi.wbxml.document.WbXmlEncoder;
import es.rickyepoderi.wbxml.document.WbXmlParser;
import java.io.IOException;
import java.util.Arrays;

/**
 * Again the WV language let encode integers as opaque data. The especification
 * says the following:
 * 
 * An integer number can be encoded as OPAQUE (0xC3) followed by an 
 * mb_u_int32 that contains the length of the integer, then the actual bytes 
 * of the integer in big -endian order (most significant bytes first).
 * Example : The 2001 (0x07D1) number would be encoded as: 0xC3 0x02 0x07 0xD1
 * 
 * In this case integers are always encoded as opaque.
 * 
 * @author ricky
 */
public class WVIntegerOpaque implements OpaqueContentPlugin {

    /**
     * The method get the string, decode as long and then write the bytes one
     * by one (until the four bytes are written or zero reached.
     * @param encoder The encoder being used in the encoding process
     * @param element The element which content or attribute is being encoded 
     * @param content The content with the integer value as a string
     * @throws IOException Some error
     */
    @Override
    public void encode(WbXmlEncoder encoder, WbXmlElement element, WbXmlContent content) throws IOException {
        if (!content.isString()) {
            throw new IOException("The content is not a String value!");
        }
        long v = Long.decode(content.getString());    
        byte[] bytes = new byte[4];
        int i;
        for (i = 3; i >= 0 && v > 0; i--) {
            bytes[i] = (byte) (v & 0xFF);
            v >>= 8;
        }
        int start = i + 1;
        encoder.writeOpaque(Arrays.copyOfRange(bytes, start, bytes.length));
    }

    /**
     * Method that gat the opaque data and reconstructs the integer as a
     * string content.
     * @param parser The parser doing the parsing/decoding process
     * @param data The data with the integer bytes (four at maximum)
     * @return The string content with the numeric value
     * @throws IOException Some error
     */
    @Override
    public WbXmlContent parse(WbXmlParser parser, byte[] data) throws IOException {
        long v = 0;
        for (int i = 0; i< data.length; i++) {
            v = (v << 8) | (data[i] & 0xFF);
        }
        return new WbXmlContent(Long.toString(v));
    }
    
}