content: // COPIED FROM org.eclipse.jface.internal.text.html
  // to get around "discouraged access" errors
  /*******************************************************************************
   * Copyright (c) 2000, 2007 IBM Corporation and others.
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * which accompanies this distribution, and is available at
   * http://www.eclipse.org/legal/epl-v10.html
   *
   * Contributors:
   *     IBM Corporation - initial API and implementation
   *******************************************************************************/
  
  package org.eclipse.wst.jsdt.internal.ui.text.html;
  
  
  import java.io.IOException;
  import java.io.PushbackReader;
  import java.io.Reader;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  
  import org.eclipse.swt.SWT;
  import org.eclipse.swt.custom.StyleRange;
  
  import org.eclipse.jface.text.TextPresentation;
  
  
  /**
   * Reads the text contents from a reader of HTML contents and translates
   * the tags or cut them out.
   * <p>
   * Moved into this package from <code>org.eclipse.jface.internal.text.revisions</code>.</p>
   */
  public class HTML2TextReader extends SubstitutionTextReader {
  
  	private static final String EMPTY_STRING= ""; //$NON-NLS-1$
  	private static final Map fgEntityLookup;
  	private static final Set fgTags;
  
  	static {
  
  		fgTags= new HashSet();
  		fgTags.add("b"); //$NON-NLS-1$
  		fgTags.add("br"); //$NON-NLS-1$
  		fgTags.add("br/"); //$NON-NLS-1$
  		fgTags.add("div"); //$NON-NLS-1$
  		fgTags.add("h1"); //$NON-NLS-1$
  		fgTags.add("h2"); //$NON-NLS-1$
  		fgTags.add("h3"); //$NON-NLS-1$
  		fgTags.add("h4"); //$NON-NLS-1$
  		fgTags.add("h5"); //$NON-NLS-1$
  		fgTags.add("p"); //$NON-NLS-1$
  		fgTags.add("dl"); //$NON-NLS-1$
  		fgTags.add("dt"); //$NON-NLS-1$
  		fgTags.add("dd"); //$NON-NLS-1$
  		fgTags.add("li"); //$NON-NLS-1$
  		fgTags.add("ul"); //$NON-NLS-1$
  		fgTags.add("pre"); //$NON-NLS-1$
  		fgTags.add("head"); //$NON-NLS-1$
  
  		fgEntityLookup= new HashMap(7);
  		fgEntityLookup.put("lt", "<"); //$NON-NLS-1$ //$NON-NLS-2$
  		fgEntityLookup.put("gt", ">"); //$NON-NLS-1$ //$NON-NLS-2$
  		fgEntityLookup.put("nbsp", " "); //$NON-NLS-1$ //$NON-NLS-2$
  		fgEntityLookup.put("amp", "&"); //$NON-NLS-1$ //$NON-NLS-2$
  		fgEntityLookup.put("circ", "^"); //$NON-NLS-1$ //$NON-NLS-2$
  		fgEntityLookup.put("tilde", "~"); //$NON-NLS-2$ //$NON-NLS-1$
  		fgEntityLookup.put("quot", "\"");		 //$NON-NLS-1$ //$NON-NLS-2$
  	}
  
  	private int fCounter= 0;
  	private TextPresentation fTextPresentation;
  	private int fBold= 0;
  	private int fStartOffset= -1;
  	private boolean fInParagraph= false;
  	private boolean fIsPreformattedText= false;
  	private boolean fIgnore= false;
  	private boolean fHeaderDetected= false;
  
  	/**
  	 * Transforms the HTML text from the reader to formatted text.
  	 *
  	 * @param reader the reader
  	 * @param presentation If not <code>null</code>, formattings will be applied to
  	 * the presentation.
  	*/
  	public HTML2TextReader(Reader reader, TextPresentation presentation) {
  		super(new PushbackReader(reader));
  		fTextPresentation= presentation;
  	}
  
  	public int read() throws IOException {
  		int c= super.read();
  		if (c != -1)
  			++ fCounter;
  		return c;
  	}
  
  	protected void startBold() {
  		if (fBold == 0)
  			fStartOffset= fCounter;
  		++ fBold;
  	}
  
  	protected void startPreformattedText() {
  		fIsPreformattedText= true;
  		setSkipWhitespace(false);
  	}
  
  	protected void stopPreformattedText() {
  		fIsPreformattedText= false;
  		setSkipWhitespace(true);
  	}
  
  	protected void stopBold() {
  		-- fBold;
  		if (fBold == 0) {
  			if (fTextPresentation != null) {
  				fTextPresentation.addStyleRange(new StyleRange(fStartOffset, fCounter - fStartOffset, null, null, SWT.BOLD));
  			}
  			fStartOffset= -1;
  		}
  	}
  
  	/*
  	 * @see org.eclipse.jdt.internal.ui.text.SubstitutionTextReader#computeSubstitution(int)
  	 */
  	protected String computeSubstitution(int c) throws IOException {
  
  		if (c == '<')
  			return  processHTMLTag();
  		else if (fIgnore)
  			return EMPTY_STRING;
  		else if (c == '&')
  			return processEntity();
  		else if (fIsPreformattedText)
  			return processPreformattedText(c);
  
  		return null;
  	}
  
  	private String html2Text(String html) {
  
  		if (html == null || html.length() == 0)
  			return EMPTY_STRING;
  
  		html= html.toLowerCase();
  		
  		String tag= html;
  		if ('/' == tag.charAt(0))
  			tag= tag.substring(1);
  
  		if (!fgTags.contains(tag))
  			return EMPTY_STRING;
  
  
  		if ("pre".equals(html)) { //$NON-NLS-1$
  			startPreformattedText();
  			return EMPTY_STRING;
  		}
  
  		if ("/pre".equals(html)) { //$NON-NLS-1$
  			stopPreformattedText();
  			return EMPTY_STRING;
  		}
  
  		if (fIsPreformattedText)
  			return EMPTY_STRING;
  
  		if ("b".equals(html)) { //$NON-NLS-1$
  			startBold();
  			return EMPTY_STRING;
  		}
  
  		if ((html.length() > 1 && html.charAt(0) == 'h' && Character.isDigit(html.charAt(1))) || "dt".equals(html)) { //$NON-NLS-1$
  			startBold();
  			return EMPTY_STRING;
  		}
  
  		if ("dl".equals(html)) //$NON-NLS-1$
  			return LINE_DELIM;
  
  		if ("dd".equals(html)) //$NON-NLS-1$
  			return "\t"; //$NON-NLS-1$
  
  		if ("li".equals(html)) //$NON-NLS-1$
  			// FIXME: this hard-coded prefix does not work for RTL languages, see https://bugs.eclipse.org/bugs/show_bug.cgi?id=91682
  			return LINE_DELIM + HTMLMessages.getString("HTML2TextReader.listItemPrefix"); //$NON-NLS-1$
  
  		if ("/b".equals(html)) { //$NON-NLS-1$
  			stopBold();
  			return EMPTY_STRING;
  		}
  
  		if ("p".equals(html))  { //$NON-NLS-1$
  			fInParagraph= true;
  			return LINE_DELIM;
  		}
  
  		if ("br".equals(html) || "br/".equals(html) || "div".equals(html)) //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
  			return LINE_DELIM;
  
  		if ("/p".equals(html))  { //$NON-NLS-1$
  			boolean inParagraph= fInParagraph;
  			fInParagraph= false;
  			return inParagraph ? EMPTY_STRING : LINE_DELIM;
  		}
  
  		if ((html.startsWith("/h") && html.length() > 2 && Character.isDigit(html.charAt(2))) || "/dt".equals(html)) { //$NON-NLS-1$ //$NON-NLS-2$
  			stopBold();
  			return LINE_DELIM;
  		}
  
  		if ("/dd".equals(html)) //$NON-NLS-1$
  			return LINE_DELIM;
  		
  		if ("head".equals(html) && !fHeaderDetected) { //$NON-NLS-1$
  			fHeaderDetected= true;
  			fIgnore= true;
  			return EMPTY_STRING;
  		}
  		
  		if ("/head".equals(html) && fHeaderDetected && fIgnore) { //$NON-NLS-1$
  			fIgnore= false;
  			return EMPTY_STRING;
  		}
  
  		return EMPTY_STRING;
  	}
  
  	/*
  	 * A '<' has been read. Process a html tag
  	 */
  	private String processHTMLTag() throws IOException {
  
  		StringBuffer buf= new StringBuffer();
  		int ch;
  		do {
  
  			ch= nextChar();
  
  			while (ch != -1 && ch != '>') {
  				buf.append(Character.toLowerCase((char) ch));
  				ch= nextChar();
  				if (ch == '"'){
  					buf.append(Character.toLowerCase((char) ch));
  					ch= nextChar();
  					while (ch != -1 && ch != '"'){
  						buf.append(Character.toLowerCase((char) ch));
  						ch= nextChar();
  					}
  				}
  				if (ch == '<'){
  					unread(ch);
  					return '<' + buf.toString();
  				}
  			}
  
  			if (ch == -1)
  				return null;
  
  			int tagLen= buf.length();
  			// needs special treatment for comments
  			if ((tagLen >= 3 && "!--".equals(buf.substring(0, 3))) //$NON-NLS-1$
  				&& !(tagLen >= 5 && "--".equals(buf.substring(tagLen - 2)))) { //$NON-NLS-1$
  				// unfinished comment
  				buf.append(ch);
  			} else {
  				break;
  			}
  		} while (true);
  
  		return html2Text(buf.toString());
  	}
  
  	private String processPreformattedText(int c) {
  		if  (c == '\r' || c == '\n')
  			fCounter++;
  		return null;
  	}
  
  
  	private void unread(int ch) throws IOException {
  		((PushbackReader) getReader()).unread(ch);
  	}
  
  	protected String entity2Text(String symbol) {
  		if (symbol.length() > 1 && symbol.charAt(0) == '#') {
  			int ch;
  			try {
  				if (symbol.charAt(1) == 'x') {
  					ch= Integer.parseInt(symbol.substring(2), 16);
  				} else {
  					ch= Integer.parseInt(symbol.substring(1), 10);
  				}
  				return EMPTY_STRING + (char)ch;
  			} catch (NumberFormatException e) {
  			}
  		} else {
  			String str= (String) fgEntityLookup.get(symbol);
  			if (str != null) {
  				return str;
  			}
  		}
  		return "&" + symbol; // not found //$NON-NLS-1$
  	}
  
  	/*
  	 * A '&' has been read. Process a entity
  	 */
  	private String processEntity() throws IOException {
  		StringBuffer buf= new StringBuffer();
  		int ch= nextChar();
  		while (Character.isLetterOrDigit((char)ch) || ch == '#') {
  			buf.append((char) ch);
  			ch= nextChar();
  		}
  
  		if (ch == ';')
  			return entity2Text(buf.toString());
  
  		buf.insert(0, '&');
  		if (ch != -1)
  			buf.append((char) ch);
  		return buf.toString();
  	}
  }
  