source: trunk/greenstone3-extensions/gs3build/src/org/greenstone/gsdl3/gs3build/util/HTMLParser.java@ 12188

package org.greenstone.gsdl3.gs3build.util;

import java.applet.*;

public class HTMLParser
{ 
    HTMLDoc document;
    int pos;
    int lastpos;

    public HTMLParser(HTMLDoc document)
    { 
    this.document = document;
    this.pos = 0;
    }
    
    public void startParse()
    { 
    this.pos = 0;
    this.lastpos = -1;
    //System.out.println("Starting "+document.urlString());
    }

    public int atParse()
    { 
    return this.pos;
    }

    public int lastParse()
    { 
    return this.lastpos;
    }

    // do a full text/tag parse
    public String fullParse()
    { 
    String reply = null;
    int end;
    int start;

    this.lastpos = this.pos;
    
    if (this.pos >= this.document.getContent().length()){
        return reply;
    }
    
    if (this.document.getContent().charAt(this.pos) == '<'){
        start = this.pos;
        
        // if we're not at the end of the document,
        // read the rest of the tag
        if (this.pos == this.document.getContent().length() - 1){
        this.pos = this.document.getContent().length();
        return reply;
        }
        
        // if the tag is a comment
        if (this.pos < this.document.getContent().length() - 3 &&
        this.document.getContent().substring(this.pos, this.pos+4).equals("<!--")){
        end = this.document.getContent().substring(this.pos).indexOf("-->") + 3 + this.pos;
        reply = this.document.getContent().substring(this.pos, end);
        this.pos = end;
        }
        else 
        { // read up to the end of the tag
            end = this.pos + 1;
            while (end < this.document.getContent().length() &&
               this.document.getContent().charAt(end) != '>'){
            end ++;
            }

            // get the whole of the tag into 'reply', and
            // set the current pos to immediately after the tag
            if (end < this.document.getContent().length()){
            reply = this.document.getContent().substring(this.pos, end + 1);
            this.pos = end + 1;
            }
            // patch the trailing > onto the tag string
            else {
            reply = this.document.getContent().substring(this.pos, end) + ">";
            this.pos = end;
            }
        }
    }
    else
        { // hunt for the beginning of the next tag
        start = this.pos;
        while ((this.pos < this.document.getContent().length()) &&
               (this.document.getContent().charAt(this.pos) != '<')){
            this.pos ++;
        }
        
        // return everything up to that tag
        reply = this.document.getContent().substring(start, this.pos);
        }
    return reply;
    }

    // Get the next tag to parse
    public String nextParse()
    { 
    String reply = null;
    int end;

    this.lastpos = this.pos;

    if (this.document.getContent() == null){
        return null;
    }
    
    if (this.pos >= this.document.getContent().length()){
        return reply;
    }
    
    // hunt for the beginning of the next tag
    while ((this.pos < this.document.getContent().length()) &&
           (this.document.getContent().charAt(this.pos) != '<')){
        this.pos ++;
    }
    
    // if we're not at the end of the document,
    // read the rest of the tag
    if (this.pos < this.document.getContent().length()){
        if (this.pos == this.document.getContent().length() - 1){
        this.pos = this.document.getContent().length();
        return reply;
        }
        
        end = this.pos + 1;
        while (end < this.document.getContent().length() &&
            this.document.getContent().charAt(end) != '>'){
        end ++;
        }
        
        // get the whole of the tag into 'reply', and
        // set the current pos to immediately after the tag
        if (end < this.document.getContent().length()){
        reply = this.document.getContent().substring(this.pos, end + 1);
        this.pos = end + 1;
        }
        else{ 
        this.pos = end;
        }
    }
    return reply;
    }
    
    
    /* --
       -- return next HREF value we come across in the document
       --
       -- NB: the checking of the quotes etc is rather lazy - and should be tidied
       --
    */
    public String nextHREF()
    { 
    String reply;
    int start, end;
    boolean quoted;
    HTMLTag tag;
    
    reply = this.nextParse();
    while (this.pos < this.document.getContent().length()){
        tag = new HTMLTag(reply);
        
        if (tag.tagName().equals("a")) {
        start = reply.indexOf("href");
        if (start == -1) {
            start = reply.indexOf("HREF");
        }
        
        if (start >= 0) {
            start += 4;
            quoted = false;
            while (reply.charAt(start) == ' ' ||
               reply.charAt(start) == '=' ||
               reply.charAt(start) == '"') {
            if (reply.charAt(start) == '"') {
                quoted = true;
            }
            start ++;
            }
            
            end = -1;
            if (quoted) {
            end = reply.indexOf('"', start+1);
            }
            if (end == -1) {
            end = reply.indexOf(' ', start+1);
            if (end == -1) {
                end = reply.length() - 1;
            }
            }
            
            reply = reply.substring(start, end);
            return reply;
        }
        }
        reply = this.nextParse();
    }
    return null;
    }

    // Return the next link in the page
    public String nextLink(AppletContext ac)
    { 
    String reply, reply2;
    int start, end;
    boolean quoted;
    HTMLTag tag;
    
    if (this.document.getContent() == null){
        return null;
    }
    
    reply = this.nextParse();
    while (this.pos < this.document.getContent().length()){
        tag = new HTMLTag(reply);
        if (tag.tagName().equals("a")){
        reply = tag.idValue("href");
        }
        else if (tag.tagName().equals("frame")){ // image tag
        reply = tag.idValue("src");
        }
        else if (tag.tagName().equals("area")) { // image map area
        reply = tag.idValue("href");
        }
        else if (tag.tagName().equals("frame")){
        reply = tag.idValue("src");
        }
        else {
        reply   = null;
        }
        
        if (reply != null){
        return reply;
        }
 
        reply = this.nextParse();
    }
    return null;
    }
}