/** * JWAP - A Java Implementation of the WAP Protocols * Copyright (C) 2001-2004 Niko Bender * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */package net.sourceforge.jwap.wsp;import java.io.ByteArrayOutputStream;import java.util.Date;/** * This class can be used to extract WSP Primitives from a byte array. The decoder * maintains a pointer (index) into the byte array which is increased when * calling one of the getter-methods. E.g. calling getUint8() to read a * octet will increase the index by one. * * @author Michel Marti */public class WSPDecoder {    private byte[] data;    private int offset;    private WSPDecoder() {    }    /**     * Construct a new WSP Decoder     * @param data the data to operate on     */    public WSPDecoder(byte[] data) {        this.data = data;    }    public byte getOctet() {        return data[offset++];    }    public short getUint8() {        return (short) (data[offset++] & 0xff); // Make it unsigned    }    public int getUint16() {        return (getUint8() << 8) | getUint8();    }    public int getUint32() {        return (getUint16() << 16) | getUint16();    }    public long getUintVar() {        int octet = 0;        long result = 0;        do {            octet = getOctet();            result <<= 7;            result |= (octet & 0x7f);        } while ((octet & 0x80) != 0);        return result;    }    public String getCString() {        ByteArrayOutputStream out = new ByteArrayOutputStream();        for (int i = getOctet(); i != 0; i = getOctet()) {            out.write(i);        }        String str = new String(out.toByteArray());        return ("".equals(str) ? null : str);    }    public String getTextString() {        int o = getOctet();        if( o != 127 ) {            seek(-1);        }            return getCString();    }        public byte[] getBytes(int count) {        byte[] ret = new byte[count];        System.arraycopy(data, offset, ret, 0, ret.length);        offset += count;        return ret;    }    public boolean isEOF() {        return offset >= data.length;    }    public int getRemainingOctets() {        int remain = data.length - offset;        return remain<0?0:remain;    }    /**     * Modify the array index     * @param offset the offset (might be negative to seek backwards)     * @return the new position of the index     */    public int seek(int offset) {        this.offset += offset;        if(this.offset < 0) {            this.offset=0;        }         return this.offset;    }    public int pos(int position) {        int last = offset;        offset=position;        return last;        }    public int pos() {        return offset;        }        public String getString(int length) {        return new String(data, offset, length);    }    /**     * Returns a short- or long-integer      */    public long getIntegerValue() {        long len = getUint8();        long ret = 0;        if( (len & 0x80) != 0 ) { // Short-Integer            ret = len & 0x7f;        } else {            seek(-1);            ret = getLongInteger();        }        return ret;    }        public long getValueLength()    {      long len = 0;      len = getUint8();      if( len == 31 ) {        len = getUintVar();      }      return len;    }        public short getShortInteger() {      return (short) (getUint8()&0x7f);          }        public long getLongInteger() {        long len = getUint8();        long ret = 0;        while(len > 0) {            len--;            ret  |= ((long)getUint8() << (len*8));        }        return ret;    }    public Date getDateValue() {        long delta = getLongInteger();        return new Date(delta*1000);    }    /** isShortInteger tests if the next value is a short int.     */    public boolean isShortInteger() {	return (data[offset] <0 ); // n.b. bytes are signed    }    /** isString tests if the next value is a string.     */    public boolean isString() {	return (data[offset] >=0x20 && data[offset] <0x80);    }}