xml.java

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package org.kxml;

import java.io.*;
import java.util.*;


/** A class containing several static xml methods, mainly for escaping
    special characters like angle brakets and quotes. This class
    contains also some (partially shared) constants for the parser and
    kDOM. */


public class Xml {

    public static final String NO_NAMESPACE = "";
   
    /** Integer constant for comments */

    public static final int COMMENT = 1;


    /** Integer constant for doctype */

    public static final int DOCTYPE = 2;


    /** Integer constant for elements */

    public static final int ELEMENT = 4;


    /** Integer constant returned by ParseEvent.getType if the end of
	the document has been reached */

    public static final int END_DOCUMENT = 8;
    

    /** Integer constant assigned to an EndTag parse event */

    public static final int END_TAG = 16;


    /** Integer constant assigned to a processing instruction */ 

    public static final int PROCESSING_INSTRUCTION = 32;
    

    /** Integer constant assigned to StartTag parse event */

    public static final int START_TAG = 64;


    /** Integer constant assigned to text nodes and events */

    public static final int TEXT = 128;


    /** Integer constant for whitespace nodes and events */

    public static final int WHITESPACE = 256;


    /** minimum escaping, quotes are not escaped */

    public static final int ENCODE_MIN = 0;

    /** forces escaping of quotes */

    public static final int ENCODE_QUOT = 1;

    /** forces escaping of all character coded greater than 127 */
    
    public static int ENCODE_128 = 2;

    /** Constant identifying wap extension events */

    public static final int WAP_EXTENSION = 1024;


    public static String normalize (String in) {
	StringBuffer result = new StringBuffer ();
	boolean first = true;
	int len = in.length ();
	for (int i = 0; i < len; i++) {

	    char c = in.charAt (i);
	    if (c <= ' ') {
		if (first) {
		    result.append (' ');
		    first = false;
		}
	    }
	    else {
		result.append (c);
		first = true;
	    }
	}
	return result.toString ();
    }

    /** unescapes an xml encoded string */
    
    public static String decode (String cooked) {
	
	StringBuffer result = new StringBuffer ();
	int i0 = 0;
	while (true) {
	    
	    int i1 = cooked.indexOf ('&', i0);
	    if (i1 == -1) break;
	    
	    result.append (cooked.substring (i0, i1));

	    int i2 = cooked.indexOf (';', i1);

	    if (i2 == -1) {
		result.append ("&amp;");
		i0 = i1+1;
		break;
	    }
	    
	    String decode = cooked.substring (i1 + 1, i2);
	    if (decode.startsWith ("#x"))
		result.append 
		    ((char) Integer.parseInt (decode.substring (2), 16));
		
	    else if (decode.startsWith ("#")) 
		result.append 
		    ((char) Integer.parseInt (decode.substring (1)));
	    
	    else if (decode.equals ("lt"))
		result.append ('<');
	    else if (decode.equals ("gt"))
		result.append ('>');
	    else if (decode.equals ("quot"))
		result.append ('"');
	    else if (decode.equals ("amp"))
		result.append ('&');
	    else if (decode.equals ("apos"))
		result.append ('\'');
	    else throw new RuntimeException 
		("illegal character entity: &"+decode+";");

	    i0 = i2+1;
	}
	result.append (cooked.substring (i0));

	return result.toString ();
    }


    /** convenience method for encode (String raw, ENCODE_MIN) */
    
    public static String encode (String raw) {
	return encode (raw, ENCODE_MIN);
    }


    /* encodes an attribute with the given name and value.  A single
	space is inserted before the name of the attribute 

    public static String encodeAttr (String name, String value) {
	return " "+name+"=\"" + encode (value, ENCODE_QUOT) + "\"";
    }
*/

    /** encodes a string escaping less than etc. */

    public static String encode (String raw, int flags) {
      
	int len = raw.length ();
    
	StringBuffer cooked = new StringBuffer (raw.length ());

	for (int i = 0; i < len; i++) {
	    char c = raw.charAt (i);
	  
	    switch (c) {
	    case '<': cooked.append ("&lt;"); break;
	    case '>': cooked.append ("&gt;"); break;
	    case '&': cooked.append ("&amp;"); break;
	    case '"': 
		{ 
		    if ((flags & ENCODE_QUOT) != 0) 
			cooked.append ("&quot;"); 
		    else
			cooked.append ('"');
		}
		break;
	    default:
		if (c >= 128 && ((flags & ENCODE_128) != 0)) 
		    cooked.append ("&#"+((int) c)+";");
		else
		    cooked.append (c);
	    }
	}
	return cooked.toString ();
    }


    /** quotes a string by adding quote chars at the beginning
	and the end and escaping all quotes and XML special
	chars contained in the string */

    public static String quote (String q) {
	return "\"" + encode (q, ENCODE_QUOT) + "\"";
    }



    /** like String.trim, but additionally all groups of one or more
	whitespace characters in the string are replaced by a single
	space (0x040) */

    public static String trim (String s) {
	
	char [] buf = new char [s.length ()]; 
	boolean ignoring = false;
	int targetPos = 0;

	for (int i = 0; i < s.length (); i++) {
	    char c = s.charAt (i);
	    
	    if (c <= ' ') 
		ignoring = true;
	    else {
		if (ignoring) {
		    if (targetPos != 0) buf [targetPos++] = ' '; 
		    ignoring = false;
		}
		buf [targetPos++] = c;
	    }
	}

	return new String (buf, 0, targetPos);
    }

}