/*
 * @(#)CSS.java	1.54 04/07/24
 *
 * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package javax.swing.text.html;

import java.awt.Color;
import java.awt.Font;
import java.awt.GraphicsEnvironment;
import java.awt.Toolkit;
import java.awt.HeadlessException;
import java.io.*;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.MalformedURLException;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;
import javax.swing.ImageIcon;
import javax.swing.SizeRequirements;
import javax.swing.text.*;

/**
 * Defines a set of
 * <a href="http://www.w3.org/TR/REC-CSS1">CSS attributes</a>
 * as a typesafe enumeration.  The HTML View implementations use
 * CSS attributes to determine how they will render. This also defines
 * methods to map between CSS/HTML/StyleConstants. Any shorthand
 * properties, such as font, are mapped to the intrinsic properties.
 * <p>The following describes the CSS properties that are suppored by the
 * rendering engine:
 * <ul><li>font-family
 *   <li>font-style
 *   <li>font-size (supports relative units)
 *   <li>font-weight
 *   <li>font
 *   <li>color
 *   <li>background-color (with the exception of transparent)
 *   <li>background-image
 *   <li>background-repeat
 *   <li>background-position
 *   <li>background
 *   <li>background-repeat
 *   <li>text-decoration (with the exception of blink and overline)
 *   <li>vertical-align (only sup and super)
 *   <li>text-align (justify is treated as center)
 *   <li>margin-top
 *   <li>margin-right
 *   <li>margin-bottom
 *   <li>margin-left
 *   <li>margin
 *   <li>padding-top
 *   <li>padding-right
 *   <li>padding-bottom
 *   <li>padding-left
 *   <li>border-style (only supports inset, outset and none)
 *   <li>list-style-type
 *   <li>list-style-position
 * </ul>
 * The following are modeled, but currently not rendered.
 * <ul><li>font-variant
 *   <li>background-attachment (background always treated as scroll)
 *   <li>word-spacing
 *   <li>letter-spacing
 *   <li>text-indent
 *   <li>text-transform
 *   <li>line-height
 *   <li>border-top-width (this is used to indicate if a border should be used)
 *   <li>border-right-width
 *   <li>border-bottom-width
 *   <li>border-left-width
 *   <li>border-width
 *   <li>border-top
 *   <li>border-right
 *   <li>border-bottom
 *   <li>border-left
 *   <li>border
 *   <li>width
 *   <li>height
 *   <li>float
 *   <li>clear
 *   <li>display
 *   <li>white-space
 *   <li>list-style
 * </ul>
 * <p><b>Note: for the time being we do not fully support relative units,
 * unless noted, so that
 * p { margin-top: 10% } will be treated as if no margin-top was specified.
 *
 * @author  Timothy Prinzing
 * @author  Scott Violet
 * @version 1.54 07/24/04
 * @see StyleSheet
 */
public class CSS implements Serializable {

    /**
     * Definitions to be used as a key on AttributeSet's
     * that might hold CSS attributes.  Since this is a
     * closed set (i.e. defined exactly by the specification),
     * it is final and cannot be extended.
     */
    public static final class Attribute {

	private Attribute(String name, String defaultValue, boolean inherited) {
	    this.name = name;
	    this.defaultValue = defaultValue;
	    this.inherited = inherited;
	}

	/**
	 * The string representation of the attribute.  This
	 * should exactly match the string specified in the
	 * CSS specification.
	 */
	public String toString() {
	    return name;
	}

	/**
	 * Fetch the default value for the attribute.
	 * If there is no default value (such as for
	 * composite attributes), null will be returned.
	 */
	public String getDefaultValue() {
	    return defaultValue;
	}

	/**
	 * Indicates if the attribute should be inherited
	 * from the parent or not.
	 */
	public boolean isInherited() {
	    return inherited;
	}

	private String name;
	private String defaultValue;
	private boolean inherited;


	public static final Attribute BACKGROUND =
	    new Attribute("background", null, false);

	public static final Attribute BACKGROUND_ATTACHMENT =
	    new Attribute("background-attachment", "scroll", false);

	public static final Attribute BACKGROUND_COLOR =
	    new Attribute("background-color", "transparent", false);

	public static final Attribute BACKGROUND_IMAGE =
	    new Attribute("background-image", "none", false);

	public static final Attribute BACKGROUND_POSITION =
	    new Attribute("background-position", null, false);

	public static final Attribute BACKGROUND_REPEAT =
	    new Attribute("background-repeat", "repeat", false);

	public static final Attribute BORDER =
	    new Attribute("border", null, false);

	public static final Attribute BORDER_BOTTOM =
	    new Attribute("border-bottom", null, false);

	public static final Attribute BORDER_BOTTOM_WIDTH =
	    new Attribute("border-bottom-width", "medium", false);

	public static final Attribute BORDER_COLOR =
	    new Attribute("border-color", null, false);

	public static final Attribute BORDER_LEFT =
	    new Attribute("border-left", null, false);

	public static final Attribute BORDER_LEFT_WIDTH =
	    new Attribute("border-left-width", "medium", false);

	public static final Attribute BORDER_RIGHT =
	    new Attribute("border-right", null, false);

	public static final Attribute BORDER_RIGHT_WIDTH =
	    new Attribute("border-right-width", "medium", false);

	public static final Attribute BORDER_STYLE =
	    new Attribute("border-style", "none", false);

	public static final Attribute BORDER_TOP =
	    new Attribute("border-top", null, false);

	public static final Attribute BORDER_TOP_WIDTH =
	    new Attribute("border-top-width", "medium", false);

	public static final Attribute BORDER_WIDTH =
	    new Attribute("border-width", "medium", false);

	public static final Attribute CLEAR =
	    new Attribute("clear", "none", false);

	public static final Attribute COLOR =
	    new Attribute("color", null, true);

	public static final Attribute DISPLAY =
	    new Attribute("display", "block", false);

	public static final Attribute FLOAT =
	    new Attribute("float", "none", false);

	public static final Attribute FONT =
	    new Attribute("font", null, true);

	public static final Attribute FONT_FAMILY =
	    new Attribute("font-family", null, true);

	public static final Attribute FONT_SIZE =
	    new Attribute("font-size", "medium", true);

	public static final Attribute FONT_STYLE =
	    new Attribute("font-style", "normal", true);

	public static final Attribute FONT_VARIANT =
	    new Attribute("font-variant", "normal", true);

	public static final Attribute FONT_WEIGHT =
	    new Attribute("font-weight", "normal", true);

	public static final Attribute HEIGHT =
	    new Attribute("height", "auto", false);

	public static final Attribute LETTER_SPACING =
	    new Attribute("letter-spacing", "normal", true);

	public static final Attribute LINE_HEIGHT =
	    new Attribute("line-height", "normal", true);

	public static final Attribute LIST_STYLE =
	    new Attribute("list-style", null, true);

	public static final Attribute LIST_STYLE_IMAGE =
	    new Attribute("list-style-image", "none", true);

	public static final Attribute LIST_STYLE_POSITION =
	    new Attribute("list-style-position", "outside", true);

	public static final Attribute LIST_STYLE_TYPE =
	    new Attribute("list-style-type", "disc", true);

	public static final Attribute MARGIN =
	    new Attribute("margin", null, false);

	public static final Attribute MARGIN_BOTTOM =
	    new Attribute("margin-bottom", "0", false);

	public static final Attribute MARGIN_LEFT =
	    new Attribute("margin-left", "0", false);

	public static final Attribute MARGIN_RIGHT =
	    new Attribute("margin-right", "0", false);

	public static final Attribute MARGIN_TOP =
	    new Attribute("margin-top", "0", false);

	public static final Attribute PADDING =
	    new Attribute("padding", null, false);

	public static final Attribute PADDING_BOTTOM =
	    new Attribute("padding-bottom", "0", false);

	public static final Attribute PADDING_LEFT =
	    new Attribute("padding-left", "0", false);

	public static final Attribute PADDING_RIGHT =
	    new Attribute("padding-right", "0", false);

	public static final Attribute PADDING_TOP =
	    new Attribute("padding-top", "0", false);

	public static final Attribute TEXT_ALIGN =
	    new Attribute("text-align", null, true);

	public static final Attribute TEXT_DECORATION =
	    new Attribute("text-decoration", "none", true);

	public static final Attribute TEXT_INDENT =
	    new Attribute("text-indent", "0", true);

	public static final Attribute TEXT_TRANSFORM =
	    new Attribute("text-transform", "none", true);

	public static final Attribute VERTICAL_ALIGN =
	    new Attribute("vertical-align", "baseline", false);

	public static final Attribute WORD_SPACING =
	    new Attribute("word-spacing", "normal", true);

	public static final Attribute WHITE_SPACE =
	    new Attribute("white-space", "normal", true);

	public static final Attribute WIDTH =
	    new Attribute("width", "auto", false);

	/*public*/ static final Attribute BORDER_SPACING = 
	    new Attribute("border-spacing", "0", true);

	/*public*/ static final Attribute CAPTION_SIDE = 
	    new Attribute("caption-side", "left", true);

	// All possible CSS attribute keys.
	static final Attribute[] allAttributes = {
	    BACKGROUND, BACKGROUND_ATTACHMENT, BACKGROUND_COLOR,
	    BACKGROUND_IMAGE, BACKGROUND_POSITION, BACKGROUND_REPEAT,
	    BORDER, BORDER_BOTTOM, BORDER_BOTTOM_WIDTH, BORDER_COLOR,
	    BORDER_LEFT, BORDER_LEFT_WIDTH, BORDER_RIGHT, BORDER_RIGHT_WIDTH,
	    BORDER_STYLE, BORDER_TOP, BORDER_TOP_WIDTH, BORDER_WIDTH,
	    CLEAR, COLOR, DISPLAY, FLOAT, FONT, FONT_FAMILY, FONT_SIZE,
	    FONT_STYLE, FONT_VARIANT, FONT_WEIGHT, HEIGHT, LETTER_SPACING,
	    LINE_HEIGHT, LIST_STYLE, LIST_STYLE_IMAGE, LIST_STYLE_POSITION,
	    LIST_STYLE_TYPE, MARGIN, MARGIN_BOTTOM, MARGIN_LEFT, MARGIN_RIGHT,
	    MARGIN_TOP, PADDING, PADDING_BOTTOM, PADDING_LEFT, PADDING_RIGHT,
	    PADDING_TOP, TEXT_ALIGN, TEXT_DECORATION, TEXT_INDENT, TEXT_TRANSFORM,
	    VERTICAL_ALIGN, WORD_SPACING, WHITE_SPACE, WIDTH, 
	    BORDER_SPACING, CAPTION_SIDE
	};

	private static final Attribute[] ALL_MARGINS =
	        { MARGIN_TOP, MARGIN_RIGHT, MARGIN_BOTTOM, MARGIN_LEFT };
	private static final Attribute[] ALL_PADDING =
	        { PADDING_TOP, PADDING_RIGHT, PADDING_BOTTOM, PADDING_LEFT };
	private static final Attribute[] ALL_BORDER_WIDTHS =
	        { BORDER_TOP_WIDTH, BORDER_RIGHT_WIDTH, BORDER_BOTTOM_WIDTH,
		  BORDER_LEFT_WIDTH };

    }

    static final class Value {

	private Value(String name) {
	    this.name = name;
	}

	/**
	 * The string representation of the attribute.  This
	 * should exactly match the string specified in the
	 * CSS specification.
	 */
	public String toString() {
	    return name;
	}

	static final Value INHERITED = new Value("inherited");
	static final Value NONE = new Value("none");
	static final Value DOTTED = new Value("dotted");
	static final Value DASHED = new Value("dashed");
	static final Value SOLID = new Value("solid");
	static final Value DOUBLE = new Value("double");
	static final Value GROOVE = new Value("groove");
	static final Value RIDGE = new Value("ridge");
	static final Value INSET = new Value("inset");
	static final Value OUTSET = new Value("outset");
	// Lists.
	static final Value BLANK_LIST_ITEM = new Value("none");
	static final Value DISC = new Value("disc");
	static final Value CIRCLE = new Value("circle");
	static final Value SQUARE = new Value("square");
	static final Value DECIMAL = new Value("decimal");
	static final Value LOWER_ROMAN = new Value("lower-roman");
	static final Value UPPER_ROMAN = new Value("upper-roman");
	static final Value LOWER_ALPHA = new Value("lower-alpha");
	static final Value UPPER_ALPHA = new Value("upper-alpha");
	// background-repeat
	static final Value BACKGROUND_NO_REPEAT = new Value("no-repeat");
	static final Value BACKGROUND_REPEAT = new Value("repeat");
	static final Value BACKGROUND_REPEAT_X = new Value("repeat-x");
	static final Value BACKGROUND_REPEAT_Y = new Value("repeat-y");
	// background-attachment
	static final Value BACKGROUND_SCROLL = new Value("scroll");
	static final Value BACKGROUND_FIXED = new Value("fixed");

	private String name;

	static final Value[] allValues = {
	    INHERITED, NONE, DOTTED, DASHED, SOLID, DOUBLE, GROOVE,
	    RIDGE, INSET, OUTSET, DISC, CIRCLE, SQUARE, DECIMAL,
	    LOWER_ROMAN, UPPER_ROMAN, LOWER_ALPHA, UPPER_ALPHA,
	    BLANK_LIST_ITEM, BACKGROUND_NO_REPEAT, BACKGROUND_REPEAT,
	    BACKGROUND_REPEAT_X, BACKGROUND_REPEAT_Y,
	    BACKGROUND_FIXED, BACKGROUND_FIXED
	};
    }

    public CSS() {
	baseFontSize = baseFontSizeIndex + 1;
	// setup the css conversion table
	valueConvertor = new Hashtable();
	valueConvertor.put(CSS.Attribute.FONT_SIZE, new FontSize());
	valueConvertor.put(CSS.Attribute.FONT_FAMILY, new FontFamily());
	valueConvertor.put(CSS.Attribute.FONT_WEIGHT, new FontWeight());
	valueConvertor.put(CSS.Attribute.BORDER_STYLE, new BorderStyle());
	Object cv = new ColorValue();
	valueConvertor.put(CSS.Attribute.COLOR, cv);
	valueConvertor.put(CSS.Attribute.BACKGROUND_COLOR, cv);
	valueConvertor.put(CSS.Attribute.BORDER_COLOR, cv);
	Object lv = new LengthValue();
	valueConvertor.put(CSS.Attribute.MARGIN_TOP, lv);
	valueConvertor.put(CSS.Attribute.MARGIN_BOTTOM, lv);
	valueConvertor.put(CSS.Attribute.MARGIN_LEFT, lv);
	valueConvertor.put(CSS.Attribute.MARGIN_RIGHT, lv);
	valueConvertor.put(CSS.Attribute.PADDING_TOP, lv);
	valueConvertor.put(CSS.Attribute.PADDING_BOTTOM, lv);
	valueConvertor.put(CSS.Attribute.PADDING_LEFT, lv);
	valueConvertor.put(CSS.Attribute.PADDING_RIGHT, lv);
	Object bv = new BorderWidthValue(null, 0);
	valueConvertor.put(CSS.Attribute.BORDER_WIDTH, lv);
	valueConvertor.put(CSS.Attribute.BORDER_TOP_WIDTH, bv);
	valueConvertor.put(CSS.Attribute.BORDER_BOTTOM_WIDTH, bv);
	valueConvertor.put(CSS.Attribute.BORDER_LEFT_WIDTH, bv);
	valueConvertor.put(CSS.Attribute.BORDER_RIGHT_WIDTH, bv);
	Object nlv = new LengthValue(true);
	valueConvertor.put(CSS.Attribute.TEXT_INDENT, nlv);
	valueConvertor.put(CSS.Attribute.WIDTH, lv);
	valueConvertor.put(CSS.Attribute.HEIGHT, lv);
	valueConvertor.put(CSS.Attribute.BORDER_SPACING, lv);
	Object sv = new StringValue();
	valueConvertor.put(CSS.Attribute.FONT_STYLE, sv);
	valueConvertor.put(CSS.Attribute.TEXT_DECORATION, sv);
	valueConvertor.put(CSS.Attribute.TEXT_ALIGN, sv);
	valueConvertor.put(CSS.Attribute.VERTICAL_ALIGN, sv);
	Object valueMapper = new CssValueMapper();
	valueConvertor.put(CSS.Attribute.LIST_STYLE_TYPE,
			   valueMapper);
	valueConvertor.put(CSS.Attribute.BACKGROUND_IMAGE,
			   new BackgroundImage());
	valueConvertor.put(CSS.Attribute.BACKGROUND_POSITION,
			   new BackgroundPosition());
	valueConvertor.put(CSS.Attribute.BACKGROUND_REPEAT,
			   valueMapper);
	valueConvertor.put(CSS.Attribute.BACKGROUND_ATTACHMENT,
			   valueMapper);
	Object generic = new CssValue();
	int n = CSS.Attribute.allAttributes.length;
	for (int i = 0; i < n; i++) {
	    CSS.Attribute key = CSS.Attribute.allAttributes[i];
	    if (valueConvertor.get(key) == null) {
		valueConvertor.put(key, generic);
	    }
	}
    }

    /**
     * Sets the base font size. <code>sz</code> is a CSS value, and is
     * not necessarily the point size. Use getPointSize to determine the
     * point size corresponding to <code>sz</code>.
     */
    void setBaseFontSize(int sz) {
	if (sz < 1)
	  baseFontSize = 0;
	else if (sz > 7)
	  baseFontSize = 7;
	else
	  baseFontSize = sz;
    }

    /**
     * Sets the base font size from the passed in string.
     */
    void setBaseFontSize(String size) {
	int relSize, absSize, diff;

	if (size != null) {
	    if (size.startsWith("+")) {
		relSize = Integer.valueOf(size.substring(1)).intValue();
		setBaseFontSize(baseFontSize + relSize);
	    } else if (size.startsWith("-")) {
		relSize = -Integer.valueOf(size.substring(1)).intValue();
		setBaseFontSize(baseFontSize + relSize);
	    } else {
		setBaseFontSize(Integer.valueOf(size).intValue());
	    }
	}
    }

    /**
     * Returns the base font size.
     */
    int getBaseFontSize() {
	return baseFontSize;
    }

    /**
     * Parses the CSS property <code>key</code> with value
     * <code>value</code> placing the result in <code>att</code>.
     */
    void addInternalCSSValue(MutableAttributeSet attr,
			     CSS.Attribute key, String value) {
	if (key == CSS.Attribute.FONT) {
	    ShorthandFontParser.parseShorthandFont(this, value, attr);
	}
	else if (key == CSS.Attribute.BACKGROUND) {
	    ShorthandBackgroundParser.parseShorthandBackground
		               (this, value, attr);
	}
	else if (key == CSS.Attribute.MARGIN) {
	    ShorthandMarginParser.parseShorthandMargin(this, value, attr,
					   CSS.Attribute.ALL_MARGINS);
	}
	else if (key == CSS.Attribute.PADDING) {
	    ShorthandMarginParser.parseShorthandMargin(this, value, attr,
					   CSS.Attribute.ALL_PADDING);
	}
	else if (key == CSS.Attribute.BORDER_WIDTH) {
	    ShorthandMarginParser.parseShorthandMargin(this, value, attr,
					   CSS.Attribute.ALL_BORDER_WIDTHS);
	}
	else {
	    Object iValue = getInternalCSSValue(key, value);
	    if (iValue != null) {
		attr.addAttribute(key, iValue);
	    }
	}
    }

    /**
     * Gets the internal CSS representation of <code>value</code> which is
     * a CSS value of the CSS attribute named <code>key</code>. The receiver
     * should not modify <code>value</code>, and the first <code>count</code>
     * strings are valid.
     */
    Object getInternalCSSValue(CSS.Attribute key, String value) {
	CssValue conv = (CssValue) valueConvertor.get(key);
        Object r = conv.parseCssValue(value);
        return r != null ? r : conv.parseCssValue(key.getDefaultValue());
    }

    /**
     * Maps from a StyleConstants to a CSS Attribute.
     */
    Attribute styleConstantsKeyToCSSKey(StyleConstants sc) {
	return (Attribute)styleConstantToCssMap.get(sc);
    }

    /**
     * Maps from a StyleConstants value to a CSS value.
     */
    Object styleConstantsValueToCSSValue(StyleConstants sc,
					 Object styleValue) {
	Object cssKey = styleConstantsKeyToCSSKey(sc);
	if (cssKey != null) {
	    CssValue conv = (CssValue)valueConvertor.get(cssKey);
	    return conv.fromStyleConstants(sc, styleValue);
	}
	return null;
    }

    /**
     * Converts the passed in CSS value to a StyleConstants value.
     * <code>key</code> identifies the CSS attribute being mapped.
     */
    Object cssValueToStyleConstantsValue(StyleConstants key, Object value) {
	if (value instanceof CssValue) {
	    return ((CssValue)value).toStyleConstants((StyleConstants)key,
						      null);
	}
	return null;
    }

    /**
     * Returns the font for the values in the passed in AttributeSet.
     * It is assumed the keys will be CSS.Attribute keys.
     * <code>sc</code> is the StyleContext that will be messaged to get
     * the font once the size, name and style have been determined.
     */
    Font getFont(StyleContext sc, AttributeSet a, int defaultSize, StyleSheet ss) {
	int size = getFontSize(a, defaultSize, ss);

	/*
	 * If the vertical alignment is set to either superscirpt or
	 * subscript we reduce the font size by 2 points.
	 */
	StringValue vAlignV = (StringValue)a.getAttribute
	                      (CSS.Attribute.VERTICAL_ALIGN);
	if ((vAlignV != null)) {
	    String vAlign = vAlignV.toString();
	    if ((vAlign.indexOf("sup") >= 0) ||
		(vAlign.indexOf("sub") >= 0)) {
		size -= 2;
	    }
	}
	
	FontFamily familyValue = (FontFamily)a.getAttribute
	                                    (CSS.Attribute.FONT_FAMILY);
	String family = (familyValue != null) ? familyValue.getValue() :
	                          "SansSerif";
	int style = Font.PLAIN;
	FontWeight weightValue = (FontWeight) a.getAttribute
	                          (CSS.Attribute.FONT_WEIGHT);
	if ((weightValue != null) && (weightValue.getValue() > 400)) {
	    style |= Font.BOLD;
	}
	Object fs = a.getAttribute(CSS.Attribute.FONT_STYLE);
	if ((fs != null) && (fs.toString().indexOf("italic") >= 0)) {
	    style |= Font.ITALIC;
	}
	Font f = sc.getFont(family, style, size);
	return f;
    }

    static int getFontSize(AttributeSet attr, int defaultSize, StyleSheet ss) {
	// PENDING(prinz) this is a 1.1 based implementation, need to also
	// have a 1.2 version.
	FontSize sizeValue = (FontSize)attr.getAttribute(CSS.Attribute.
							 FONT_SIZE);

	return (sizeValue != null) ? (int)sizeValue.getValue(attr, ss) :
	                             defaultSize;
    }

    /**
     * Takes a set of attributes and turn it into a color
     * specification.  This might be used to specify things
     * like brighter, more hue, etc.
     * This will return null if there is no value for <code>key</code>.
     *
     * @param key CSS.Attribute identifying where color is stored.
     * @param a the set of attributes
     * @return the color
     */
    Color getColor(AttributeSet a, CSS.Attribute key) {
	ColorValue cv = (ColorValue) a.getAttribute(key);
	if (cv != null) {
	    return cv.getValue();
	}
	return null;
    }

    /**
     * Returns the size of a font from the passed in string.
     *
     * @param size CSS string describing font size
     * @param baseFontSize size to use for relative units.
     */
    float getPointSize(String size, StyleSheet ss) {
	int relSize, absSize, diff, index;
	if (size != null) {
	    if (size.startsWith("+")) {
		relSize = Integer.valueOf(size.substring(1)).intValue();
		return getPointSize(baseFontSize + relSize, ss);
	    } else if (size.startsWith("-")) {
		relSize = -Integer.valueOf(size.substring(1)).intValue();
		return getPointSize(baseFontSize + relSize, ss);
	    } else {
		absSize = Integer.valueOf(size).intValue();
		return getPointSize(absSize, ss);
	    }
	}
	return 0;
    }

    /**
     * Returns the length of the attribute in <code>a</code> with
     * key <code>key</code>.
     */
    float getLength(AttributeSet a, CSS.Attribute key, StyleSheet ss) {
	LengthValue lv = (LengthValue) a.getAttribute(key);
	float len = (lv != null) ? lv.getValue(ss.isW3CLengthUnits()) : 0;
	return len;
    }

    /**
     * Convert a set of HTML attributes to an equivalent
     * set of CSS attributes.
     *
     * @param AttributeSet containing the HTML attributes.
     * @return AttributeSet containing the corresponding CSS attributes.
     *        The AttributeSet will be empty if there are no mapping
     *        CSS attributes.
     */
    AttributeSet translateHTMLToCSS(AttributeSet htmlAttrSet) {
	MutableAttributeSet cssAttrSet = new SimpleAttributeSet();
	Element elem = (Element)htmlAttrSet;
	HTML.Tag tag = getHTMLTag(htmlAttrSet);
	if ((tag == HTML.Tag.TD) || (tag == HTML.Tag.TH)) {
	    // translate border width into the cells
	    AttributeSet tableAttr = elem.getParentElement().
		                     getParentElement().getAttributes();
	    translateAttribute(HTML.Attribute.BORDER, tableAttr, cssAttrSet);
	    String pad = (String)tableAttr.getAttribute(HTML.Attribute.CELLPADDING);
	    if (pad != null) {
		LengthValue v = 
		    (LengthValue)getInternalCSSValue(CSS.Attribute.PADDING_TOP, pad);
		v.span = (v.span < 0) ? 0 : v.span;
		cssAttrSet.addAttribute(CSS.Attribute.PADDING_TOP, v);
		cssAttrSet.addAttribute(CSS.Attribute.PADDING_BOTTOM, v);
		cssAttrSet.addAttribute(CSS.Attribute.PADDING_LEFT, v);
		cssAttrSet.addAttribute(CSS.Attribute.PADDING_RIGHT, v);
	    }
	}
	if (elem.isLeaf()) {
	    translateEmbeddedAttributes(htmlAttrSet, cssAttrSet);
	} else {
	    translateAttributes(tag, htmlAttrSet, cssAttrSet);
	}
	if (tag == HTML.Tag.CAPTION) {
	    /* 
	     * Navigator uses ALIGN for caption placement and IE uses VALIGN.
	     */
	    Object v = htmlAttrSet.getAttribute(HTML.Attribute.ALIGN);
	    if ((v != null) && (v.equals("top") || v.equals("bottom"))) {
		cssAttrSet.addAttribute(CSS.Attribute.CAPTION_SIDE, v);
		cssAttrSet.removeAttribute(CSS.Attribute.TEXT_ALIGN);
	    } else {
		v = htmlAttrSet.getAttribute(HTML.Attribute.VALIGN);
		if (v != null) {
		    cssAttrSet.addAttribute(CSS.Attribute.CAPTION_SIDE, v);
		}
	    }
	}
	return cssAttrSet;
    }

    private static final Hashtable attributeMap = new Hashtable();
    private static final Hashtable valueMap = new Hashtable();

    /**
     * The hashtable and the static initalization block below,
     * set up a mapping from well-known HTML attributes to
     * CSS attributes.  For the most part, there is a 1-1 mapping
     * between the two.  However in the case of certain HTML
     * attributes for example HTML.Attribute.VSPACE or
     * HTML.Attribute.HSPACE, end up mapping to two CSS.Attribute's.
     * Therefore, the value associated with each HTML.Attribute.
     * key ends up being an array of CSS.Attribute.* objects.
     */
    private static final Hashtable htmlAttrToCssAttrMap = new Hashtable(20);

    /**
     * The hashtable and static initialization that follows sets
     * up a translation from StyleConstants (i.e. the <em>well known</em>
     * attributes) to the associated CSS attributes.
     */
    private static final Hashtable styleConstantToCssMap = new Hashtable(17);
    /** Maps from HTML value to a CSS value. Used in internal mapping. */
    private static final Hashtable htmlValueToCssValueMap = new Hashtable(8);
    /** Maps from CSS value (string) to internal value. */
    private static final Hashtable cssValueToInternalValueMap = new Hashtable(13);

    /** Used to indicate if a font family name is valid. */
    private static Hashtable fontMapping = new Hashtable();

    static {
	// load the attribute map
	for (int i = 0; i < Attribute.allAttributes.length; i++ ) {
	    attributeMap.put(Attribute.allAttributes[i].toString(),
			     Attribute.allAttributes[i]);
	}
	// load the value map
	for (int i = 0; i < Value.allValues.length; i++ ) {
	    valueMap.put(Value.allValues[i].toString(), 
			     Value.allValues[i]);
	}

	htmlAttrToCssAttrMap.put(HTML.Attribute.COLOR,
				 new CSS.Attribute[]{CSS.Attribute.COLOR});
	htmlAttrToCssAttrMap.put(HTML.Attribute.TEXT,
				 new CSS.Attribute[]{CSS.Attribute.COLOR});
	htmlAttrToCssAttrMap.put(HTML.Attribute.CLEAR,
				 new CSS.Attribute[]{CSS.Attribute.CLEAR});
	htmlAttrToCssAttrMap.put(HTML.Attribute.BACKGROUND,
				 new CSS.Attribute[]{CSS.Attribute.BACKGROUND_IMAGE});
	htmlAttrToCssAttrMap.put(HTML.Attribute.BGCOLOR,
				 new CSS.Attribute[]{CSS.Attribute.BACKGROUND_COLOR});
	htmlAttrToCssAttrMap.put(HTML.Attribute.WIDTH,
				 new CSS.Attribute[]{CSS.Attribute.WIDTH});
	htmlAttrToCssAttrMap.put(HTML.Attribute.HEIGHT,
				 new CSS.Attribute[]{CSS.Attribute.HEIGHT});
	htmlAttrToCssAttrMap.put(HTML.Attribute.BORDER,
				 new CSS.Attribute[]{CSS.Attribute.BORDER_TOP_WIDTH, CSS.Attribute.BORDER_RIGHT_WIDTH, CSS.Attribute.BORDER_BOTTOM_WIDTH, CSS.Attribute.BORDER_LEFT_WIDTH});
	htmlAttrToCssAttrMap.put(HTML.Attribute.CELLPADDING,
				 new CSS.Attribute[]{CSS.Attribute.PADDING});
	htmlAttrToCssAttrMap.put(HTML.Attribute.CELLSPACING,
				 new CSS.Attribute[]{CSS.Attribute.BORDER_SPACING});
	htmlAttrToCssAttrMap.put(HTML.Attribute.MARGINWIDTH,
				 new CSS.Attribute[]{CSS.Attribute.MARGIN_LEFT,
						     CSS.Attribute.MARGIN_RIGHT});
	htmlAttrToCssAttrMap.put(HTML.Attribute.MARGINHEIGHT,
				 new CSS.Attribute[]{CSS.Attribute.MARGIN_TOP,
						     CSS.Attribute.MARGIN_BOTTOM});
	htmlAttrToCssAttrMap.put(HTML.Attribute.HSPACE,
				 new CSS.Attribute[]{CSS.Attribute.PADDING_LEFT,
						     CSS.Attribute.PADDING_RIGHT});
	htmlAttrToCssAttrMap.put(HTML.Attribute.VSPACE,
				 new CSS.Attribute[]{CSS.Attribute.PADDING_BOTTOM,
						     CSS.Attribute.PADDING_TOP});
	htmlAttrToCssAttrMap.put(HTML.Attribute.FACE,
				 new CSS.Attribute[]{CSS.Attribute.FONT_FAMILY});
	htmlAttrToCssAttrMap.put(HTML.Attribute.SIZE,
				 new CSS.Attribute[]{CSS.Attribute.FONT_SIZE});
	htmlAttrToCssAttrMap.put(HTML.Attribute.VALIGN,
				 new CSS.Attribute[]{CSS.Attribute.VERTICAL_ALIGN});
	htmlAttrToCssAttrMap.put(HTML.Attribute.ALIGN,
				 new CSS.Attribute[]{CSS.Attribute.VERTICAL_ALIGN,
						     CSS.Attribute.TEXT_ALIGN,
						     CSS.Attribute.FLOAT});
	htmlAttrToCssAttrMap.put(HTML.Attribute.TYPE,
				 new CSS.Attribute[]{CSS.Attribute.LIST_STYLE_TYPE});
	htmlAttrToCssAttrMap.put(HTML.Attribute.NOWRAP,
				 new CSS.Attribute[]{CSS.Attribute.WHITE_SPACE});

	// initialize StyleConstants mapping 
	styleConstantToCssMap.put(StyleConstants.FontFamily, 
				  CSS.Attribute.FONT_FAMILY);
	styleConstantToCssMap.put(StyleConstants.FontSize, 
				  CSS.Attribute.FONT_SIZE);
	styleConstantToCssMap.put(StyleConstants.Bold, 
				  CSS.Attribute.FONT_WEIGHT);
	styleConstantToCssMap.put(StyleConstants.Italic, 
				  CSS.Attribute.FONT_STYLE);
	styleConstantToCssMap.put(StyleConstants.Underline, 
				  CSS.Attribute.TEXT_DECORATION);
	styleConstantToCssMap.put(StyleConstants.StrikeThrough, 
				  CSS.Attribute.TEXT_DECORATION);
	styleConstantToCssMap.put(StyleConstants.Superscript, 
				  CSS.Attribute.VERTICAL_ALIGN);
	styleConstantToCssMap.put(StyleConstants.Subscript, 
				  CSS.Attribute.VERTICAL_ALIGN);
	styleConstantToCssMap.put(StyleConstants.Foreground, 
				  CSS.Attribute.COLOR);
	styleConstantToCssMap.put(StyleConstants.Background, 
				  CSS.Attribute.BACKGROUND_COLOR);
	styleConstantToCssMap.put(StyleConstants.FirstLineIndent, 
				  CSS.Attribute.TEXT_INDENT);
	styleConstantToCssMap.put(StyleConstants.LeftIndent, 
				  CSS.Attribute.MARGIN_LEFT);
	styleConstantToCssMap.put(StyleConstants.RightIndent, 
				  CSS.Attribute.MARGIN_RIGHT);
	styleConstantToCssMap.put(StyleConstants.SpaceAbove, 
				  CSS.Attribute.MARGIN_TOP);
	styleConstantToCssMap.put(StyleConstants.SpaceBelow, 
				  CSS.Attribute.MARGIN_BOTTOM);
	styleConstantToCssMap.put(StyleConstants.Alignment, 
				  CSS.Attribute.TEXT_ALIGN);

	// HTML->CSS
	htmlValueToCssValueMap.put("disc", CSS.Value.DISC);
	htmlValueToCssValueMap.put("square", CSS.Value.SQUARE);
	htmlValueToCssValueMap.put("circle", CSS.Value.CIRCLE);
	htmlValueToCssValueMap.put("1", CSS.Value.DECIMAL);
	htmlValueToCssValueMap.put("a", CSS.Value.LOWER_ALPHA);
	htmlValueToCssValueMap.put("A", CSS.Value.UPPER_ALPHA);
	htmlValueToCssValueMap.put("i", CSS.Value.LOWER_ROMAN);
	htmlValueToCssValueMap.put("I", CSS.Value.UPPER_ROMAN);

	// CSS-> internal CSS
	cssValueToInternalValueMap.put("none", CSS.Value.NONE);
	cssValueToInternalValueMap.put("disc", CSS.Value.DISC);
	cssValueToInternalValueMap.put("square", CSS.Value.SQUARE);
	cssValueToInternalValueMap.put("circle", CSS.Value.CIRCLE);
	cssValueToInternalValueMap.put("decimal", CSS.Value.DECIMAL);
	cssValueToInternalValueMap.put("lower-roman", CSS.Value.LOWER_ROMAN);
	cssValueToInternalValueMap.put("upper-roman", CSS.Value.UPPER_ROMAN);
	cssValueToInternalValueMap.put("lower-alpha", CSS.Value.LOWER_ALPHA);
	cssValueToInternalValueMap.put("upper-alpha", CSS.Value.UPPER_ALPHA);
	cssValueToInternalValueMap.put("repeat", CSS.Value.BACKGROUND_REPEAT);
	cssValueToInternalValueMap.put("no-repeat",
				       CSS.Value.BACKGROUND_NO_REPEAT);
	cssValueToInternalValueMap.put("repeat-x",
				       CSS.Value.BACKGROUND_REPEAT_X);
	cssValueToInternalValueMap.put("repeat-y",
				       CSS.Value.BACKGROUND_REPEAT_Y);
	cssValueToInternalValueMap.put("scroll",
				       CSS.Value.BACKGROUND_SCROLL);
	cssValueToInternalValueMap.put("fixed",
				       CSS.Value.BACKGROUND_FIXED);

        // Register all the CSS attribute keys for archival/unarchival
	Object[] keys = CSS.Attribute.allAttributes;
	try {
	    for (int i = 0; i < keys.length; i++) {
		StyleContext.registerStaticAttributeKey(keys[i]);
	    }
	} catch (Throwable e) {
	    e.printStackTrace();
	}

        // Register all the CSS Values for archival/unarchival
	keys = CSS.Value.allValues;
	try {
	    for (int i = 0; i < keys.length; i++) {
		StyleContext.registerStaticAttributeKey(keys[i]);
	    }
	} catch (Throwable e) {
	    e.printStackTrace();
	}
    }

    /**
     * Return the set of all possible CSS attribute keys.
     */
    public static Attribute[] getAllAttributeKeys() {
	Attribute[] keys = new Attribute[Attribute.allAttributes.length];
	System.arraycopy(Attribute.allAttributes, 0, keys, 0, Attribute.allAttributes.length);
	return keys;
    }

    /**
     * Translates a string to a <code>CSS.Attribute</code> object.
     * This will return <code>null</code> if there is no attribute
     * by the given name.
     *
     * @param name the name of the CSS attribute to fetch the
     *  typesafe enumeration for
     * @return the <code>CSS.Attribute</code> object,
     *  or <code>null</code> if the string
     *  doesn't represent a valid attribute key
     */
    public static final Attribute getAttribute(String name) {
	return (Attribute) attributeMap.get(name);
    }

    /**
     * Translates a string to a <code>CSS.Value</code> object.
     * This will return <code>null</code> if there is no value
     * by the given name.
     *
     * @param name the name of the CSS value to fetch the
     *  typesafe enumeration for
     * @return the <code>CSS.Value</code> object, 
     *  or <code>null</code> if the string
     *  doesn't represent a valid CSS value name; this does
     *  not mean that it doesn't represent a valid CSS value
     */
    static final Value getValue(String name) {
	return (Value) valueMap.get(name);
    }


    //
    // Conversion related methods/classes
    //

    /**
     * Returns a URL for the given CSS url string. If relative,
     * <code>base</code> is used as the parent. If a valid URL can not
     * be found, this will not throw a MalformedURLException, instead 
     * null will be returned.
     */
    static URL getURL(URL base, String cssString) {
	if (cssString == null) {
	    return null;
	}
	if (cssString.startsWith("url(") &&
	    cssString.endsWith(")")) {
	    cssString = cssString.substring(4, cssString.length() - 1);
	}
	// Absolute first
	try {
	    URL url = new URL(cssString);
	    if (url != null) {
		return url;
	    }
	} catch (MalformedURLException mue) {
	}
	// Then relative
	if (base != null) {
	    // Relative URL, try from base
	    try {
		URL url = new URL(base, cssString);
		return url;
	    }
	    catch (MalformedURLException muee) {
	    }
	}
	return null;
    }

    /**
     * Converts a type Color to a hex string
     * in the format "#RRGGBB"
     */
    static String colorToHex(Color color) {

      String colorstr = new String("#");

      // Red
      String str = Integer.toHexString(color.getRed());
      if (str.length() > 2)
	str = str.substring(0, 2);
      else if (str.length() < 2)
	colorstr += "0" + str;
      else
	colorstr += str;

      // Green
      str = Integer.toHexString(color.getGreen());
      if (str.length() > 2)
	str = str.substring(0, 2);
      else if (str.length() < 2)
	colorstr += "0" + str;
      else
	colorstr += str;

      // Blue
      str = Integer.toHexString(color.getBlue());
      if (str.length() > 2)
	str = str.substring(0, 2);
      else if (str.length() < 2)
	colorstr += "0" + str;
      else
	colorstr += str;

      return colorstr;
    }

     /**
      * Convert a "#FFFFFF" hex string to a Color.
      * If the color specification is bad, an attempt
      * will be made to fix it up.
      */
    static final Color hexToColor(String value) {
	String digits;
	int n = value.length();
	if (value.startsWith("#")) {
	    digits = value.substring(1, Math.min(value.length(), 7));
	} else {
	    digits = value;
	}
	String hstr = "0x" + digits;
	Color c;
	try {
	    c = Color.decode(hstr);
	} catch (NumberFormatException nfe) {
	    c = null;
	}
	 return c;
     }

    /**
     * Convert a color string such as "RED" or "#NNNNNN" or "rgb(r, g, b)"
     * to a Color.
     */
    static Color stringToColor(String str) {
      Color color = null;

      if (str.length() == 0)
        color = Color.black;
      else if (str.startsWith("rgb(")) {
          color = parseRGB(str);
      }
      else if (str.charAt(0) == '#')
        color = hexToColor(str);
      else if (str.equalsIgnoreCase("Black"))
        color = hexToColor("#000000");
      else if(str.equalsIgnoreCase("Silver"))
        color = hexToColor("#C0C0C0");
      else if(str.equalsIgnoreCase("Gray"))
        color = hexToColor("#808080");
      else if(str.equalsIgnoreCase("White"))
        color = hexToColor("#FFFFFF");
      else if(str.equalsIgnoreCase("Maroon"))
        color = hexToColor("#800000");
      else if(str.equalsIgnoreCase("Red"))
        color = hexToColor("#FF0000");
      else if(str.equalsIgnoreCase("Purple"))
        color = hexToColor("#800080");
      else if(str.equalsIgnoreCase("Fuchsia"))
        color = hexToColor("#FF00FF");
      else if(str.equalsIgnoreCase("Green"))
        color = hexToColor("#008000");
      else if(str.equalsIgnoreCase("Lime"))
        color = hexToColor("#00FF00");
      else if(str.equalsIgnoreCase("Olive"))
        color = hexToColor("#808000");
      else if(str.equalsIgnoreCase("Yellow"))
        color = hexToColor("#FFFF00");
      else if(str.equalsIgnoreCase("Navy"))
        color = hexToColor("#000080");
      else if(str.equalsIgnoreCase("Blue"))
        color = hexToColor("#0000FF");
      else if(str.equalsIgnoreCase("Teal"))
        color = hexToColor("#008080");
      else if(str.equalsIgnoreCase("Aqua"))
        color = hexToColor("#00FFFF");
      else
	  color = hexToColor(str); // sometimes get specified without leading #
      return color;
    }

    /**
     * Parses a String in the format <code>rgb(r, g, b)</code> where
     * each of the Color components is either an integer, or a floating number
     * with a % after indicating a percentage value of 255. Values are
     * constrained to fit with 0-255. The resulting Color is returned.
     */
    private static Color parseRGB(String string) {
        // Find the next numeric char
        int[] index = new int[1];

        index[0] = 4;
        int red = getColorComponent(string, index);
        int green = getColorComponent(string, index);
        int blue = getColorComponent(string, index);

        return new Color(red, green, blue);
    }

    /**
     * Returns the next integer value from <code>string</code> starting
     * at <code>index[0]</code>. The value can either can an integer, or
     * a percentage (floating number ending with %), in which case it is
     * multiplied by 255.
     */
    private static int getColorComponent(String string, int[] index) {
        int length = string.length();
        char aChar;

        // Skip non-decimal chars
        while(index[0] < length && (aChar = string.charAt(index[0])) != '-' &&
              !Character.isDigit(aChar) && aChar != '.') {
            index[0]++;
        }

        int start = index[0];

        if (start < length && string.charAt(index[0]) == '-') {
            index[0]++;
        }
        while(index[0] < length &&
                         Character.isDigit(string.charAt(index[0]))) {
            index[0]++;
        }
        if (index[0] < length && string.charAt(index[0]) == '.') {
            // Decimal value
            index[0]++;
            while(index[0] < length &&
                  Character.isDigit(string.charAt(index[0]))) {
                index[0]++;
            }
        }
        if (start != index[0]) {
            try {
                float value = Float.parseFloat(string.substring
                                               (start, index[0]));

                if (index[0] < length && string.charAt(index[0]) == '%') {
                    index[0]++;
                    value = value * 255f / 100f;
                }
                return Math.min(255, Math.max(0, (int)value));
            } catch (NumberFormatException nfe) {
                // Treat as 0
            }
        }
        return 0;
    }

    static int getIndexOfSize(float pt, int[] sizeMap) {
        for (int i = 0; i < sizeMap.length; i ++ )
                if (pt <= sizeMap[i])
                        return i + 1;
        return sizeMap.length;
    }

    static int getIndexOfSize(float pt, StyleSheet ss) {
        return getIndexOfSize(pt, ss.getSizeMap());
    }


    /**
     * @return an array of all the strings in <code>value</code>
     *         that are separated by whitespace.
     */
    static String[] parseStrings(String value) {
	int         current, last;
	int         length = (value == null) ? 0 : value.length();
	Vector      temp = new Vector(4);

	current = 0;
	while (current < length) {
	    // Skip ws
	    while (current < length && Character.isWhitespace
		   (value.charAt(current))) {
		current++;
	    }
	    last = current;
	    while (current < length && !Character.isWhitespace
		   (value.charAt(current))) {
		current++;
	    }
	    if (last != current) {
		temp.addElement(value.substring(last, current));
	    }
	    current++;
	}
	String[] retValue = new String[temp.size()];
	temp.copyInto(retValue);
	return retValue;
    }

    /**
     * Return the point size, given a size index. Legal HTML index sizes
     * are 1-7.
     */
    float getPointSize(int index, StyleSheet ss) {
        int[] sizeMap = (ss != null) ? ss.getSizeMap() : 
            StyleSheet.sizeMapDefault;
        --index;
	if (index < 0)
	  return sizeMap[0];
	else if (index > sizeMap.length - 1)
	  return sizeMap[sizeMap.length - 1];
	else
	  return sizeMap[index];
    }


    private void translateEmbeddedAttributes(AttributeSet htmlAttrSet,
					     MutableAttributeSet cssAttrSet) {
	Enumeration keys = htmlAttrSet.getAttributeNames();
	if (htmlAttrSet.getAttribute(StyleConstants.NameAttribute) ==
	    HTML.Tag.HR) {
	    // HR needs special handling due to us treating it as a leaf.
	    translateAttributes(HTML.Tag.HR, htmlAttrSet, cssAttrSet);
	}
	while (keys.hasMoreElements()) {
	    Object key = keys.nextElement();
	    if (key instanceof HTML.Tag) {
		HTML.Tag tag = (HTML.Tag)key;
		Object o = htmlAttrSet.getAttribute(tag);
		if (o != null && o instanceof AttributeSet) {
		    translateAttributes(tag, (AttributeSet)o, cssAttrSet);
		}
	    } else if (key instanceof CSS.Attribute) {
		cssAttrSet.addAttribute(key, htmlAttrSet.getAttribute(key));
	    }
	}
    }

    private void translateAttributes(HTML.Tag tag,
					    AttributeSet htmlAttrSet,
					    MutableAttributeSet cssAttrSet) {
	Enumeration names = htmlAttrSet.getAttributeNames();
	while (names.hasMoreElements()) {
	    Object name = names.nextElement();

	    if (name instanceof HTML.Attribute) {
		HTML.Attribute key = (HTML.Attribute)name;

		/*
		 * HTML.Attribute.ALIGN needs special processing.
		 * It can map to to 1 of many(3) possible CSS attributes
		 * depending on the nature of the tag the attribute is
		 * part off and depending on the value of the attribute.
		 */
		if (key == HTML.Attribute.ALIGN) {
		    String htmlAttrValue = (String)htmlAttrSet.getAttribute(HTML.Attribute.ALIGN);
		    if (htmlAttrValue != null) {
			CSS.Attribute cssAttr = getCssAlignAttribute(tag, htmlAttrSet);
			if (cssAttr != null) {
			    Object o = getCssValue(cssAttr, htmlAttrValue);
			    if (o != null) {
				cssAttrSet.addAttribute(cssAttr, o);
			    }
			}
		    }
		} else {

		    /*
		     * The html size attribute has a mapping in the CSS world only
		     * if it is par of a font or base font tag.
		     */

		    if (key == HTML.Attribute.SIZE && !isHTMLFontTag(tag)) {
			continue;
		    }

		    translateAttribute(key, htmlAttrSet, cssAttrSet);
		}
	    } else if (name instanceof CSS.Attribute) {
		cssAttrSet.addAttribute(name, htmlAttrSet.getAttribute(name));
	    }
	}
    }

    private void translateAttribute(HTML.Attribute key,
					   AttributeSet htmlAttrSet,
					   MutableAttributeSet cssAttrSet) {
	/*
	 * In the case of all remaining HTML.Attribute's they
	 * map to 1 or more CCS.Attribute.
	 */
	CSS.Attribute[] cssAttrList = getCssAttribute(key);
	
	String htmlAttrValue = (String)htmlAttrSet.getAttribute(key);
	
	if (cssAttrList == null || htmlAttrValue == null) {
	    return;
	}
	for (int i = 0; i < cssAttrList.length; i++) {
	    Object o = getCssValue(cssAttrList[i], htmlAttrValue);
	    if (o != null) {
		cssAttrSet.addAttribute(cssAttrList[i], o);
	    }
	}
    }

    /**
     * Given a CSS.Attribute object and its corresponding HTML.Attribute's
     * value, this method returns a CssValue object to associate with the
     * CSS attribute.
     *
     * @param the CSS.Attribute
     * @param a String containing the value associated HTML.Attribtue.
     */
    Object getCssValue(CSS.Attribute cssAttr, String htmlAttrValue) {
	CssValue value = (CssValue)valueConvertor.get(cssAttr);
	Object o = value.parseHtmlValue(htmlAttrValue);
	return o;
    }

    /**
     * Maps an HTML.Attribute object to its appropriate CSS.Attributes.
     *
     * @param HTML.Attribute
     * @return CSS.Attribute[]
     */
    private CSS.Attribute[] getCssAttribute(HTML.Attribute hAttr) {
	return (CSS.Attribute[])htmlAttrToCssAttrMap.get(hAttr);
    }

    /**
     * Maps HTML.Attribute.ALIGN to either:
     *     CSS.Attribute.TEXT_ALIGN
     *     CSS.Attribute.FLOAT
     *     CSS.Attribute.VERTICAL_ALIGN
     * based on the tag associated with the attribute and the
     * value of the attribute.
     *
     * @param AttributeSet containing HTML attributes.
     * @return CSS.Attribute mapping for HTML.Attribute.ALIGN.
     */
    private CSS.Attribute getCssAlignAttribute(HTML.Tag tag,
						   AttributeSet htmlAttrSet) {
	return CSS.Attribute.TEXT_ALIGN;
/*
	String htmlAttrValue = (String)htmlAttrSet.getAttribute(HTML.Attribute.ALIGN);
	CSS.Attribute cssAttr = CSS.Attribute.TEXT_ALIGN;
	if (htmlAttrValue != null && htmlAttrSet instanceof Element) {
	    Element elem = (Element)htmlAttrSet;
	    if (!elem.isLeaf() && tag.isBlock() && validTextAlignValue(htmlAttrValue)) {
		return CSS.Attribute.TEXT_ALIGN;
	    } else if (isFloater(htmlAttrValue)) {
		return CSS.Attribute.FLOAT;
	    } else if (elem.isLeaf()) {
		return CSS.Attribute.VERTICAL_ALIGN;
	    }
 	}
	return null;
	*/
    }

    /**
     * Fetches the tag associated with the HTML AttributeSet.
     *
     * @param  AttributeSet containing the HTML attributes.
     * @return HTML.Tag
     */
    private HTML.Tag getHTMLTag(AttributeSet htmlAttrSet) {
	Object o = htmlAttrSet.getAttribute(StyleConstants.NameAttribute);
	if (o instanceof HTML.Tag) {
	    HTML.Tag tag = (HTML.Tag) o;
	    return tag;
	}
	return null;
    }


    private boolean isHTMLFontTag(HTML.Tag tag) {
	return (tag != null && ((tag == HTML.Tag.FONT) || (tag == HTML.Tag.BASEFONT)));
    }


    private boolean isFloater(String alignValue) {
	return (alignValue.equals("left") || alignValue.equals("right"));
    }

    private boolean validTextAlignValue(String alignValue) {
	return (isFloater(alignValue) || alignValue.equals("center"));
    }

    /**
     * Base class to CSS values in the attribute sets.  This
     * is intended to act as a convertor to/from other attribute
     * formats.
     * <p>
     * The CSS parser uses the parseCssValue method to convert
     * a string to whatever format is appropriate a given key
     * (i.e. these convertors are stored in a map using the
     * CSS.Attribute as a key and the CssValue as the value).
     * <p>
     * The HTML to CSS conversion process first converts the
     * HTML.Attribute to a CSS.Attribute, and then calls
     * the parseHtmlValue method on the value of the HTML
     * attribute to produce the corresponding CSS value.
     * <p>
     * The StyleConstants to CSS conversion process first 
     * converts the StyleConstants attribute to a 
     * CSS.Attribute, and then calls the fromStyleConstants
     * method to convert the StyleConstants value to a 
     * CSS value.
     * <p>
     * The CSS to StyleConstants conversion process first
     * converts the StyleConstants attribute to a 
     * CSS.Attribute, and then calls the toStyleConstants
     * method to convert the CSS value to a StyleConstants
     * value.
     */
    static class CssValue implements Serializable {

	/**
	 * Convert a CSS value string to the internal format
	 * (for fast processing) used in the attribute sets.
	 * The fallback storage for any value that we don't
	 * have a special binary format for is a String. 
	 */
	Object parseCssValue(String value) {
	    return value;
	}

	/**
	 * Convert an HTML attribute value to a CSS attribute
	 * value.  If there is no conversion, return null.
	 * This is implemented to simply forward to the CSS
	 * parsing by default (since some of the attribute
	 * values are the same).  If the attribute value
	 * isn't recognized as a CSS value it is generally
	 * returned as null.
	 */
	Object parseHtmlValue(String value) {
	    return parseCssValue(value);
	}

	/**
	 * Converts a <code>StyleConstants</code> attribute value to
	 * a CSS attribute value.  If there is no conversion,
	 * returns <code>null</code>.  By default, there is no conversion.
	 * 
	 * @param key the <code>StyleConstants</code> attribute
	 * @param value the value of a <code>StyleConstants</code>
         *   attribute to be converted
	 * @return the CSS value that represents the 
         *   <code>StyleConstants</code> value
	 */
	Object fromStyleConstants(StyleConstants key, Object value) {
	    return null;
	}

	/**
	 * Converts a CSS attribute value to a 
         * <code>StyleConstants</code>
	 * value.  If there is no conversion, returns
         * <code>null</code>.
	 * By default, there is no conversion.
	 *
	 * @param key the <code>StyleConstants</code> attribute
	 * @param v the view containing <code>AttributeSet</code>
	 * @return the <code>StyleConstants</code> attribute value that 
	 *   represents the CSS attribute value
	 */
	Object toStyleConstants(StyleConstants key, View v) {
	    return null;
	}

	/**
	 * Return the CSS format of the value
	 */
        public String toString() {
	    return svalue;
	}

	/**
	 * The value as a string... before conversion to a
	 * binary format.
	 */
	String svalue;
    }

    /**
     * By default CSS attributes are represented as simple
     * strings.  They also have no conversion to/from
     * StyleConstants by default. This class represents the 
     * value as a string (via the superclass), but 
     * provides StyleConstants conversion support for the 
     * CSS attributes that are held as strings.
     */
    static class StringValue extends CssValue {

	/**
	 * Convert a CSS value string to the internal format
	 * (for fast processing) used in the attribute sets.
	 * This produces a StringValue, so that it can be
	 * used to convert from CSS to StyleConstants values.
	 */
	Object parseCssValue(String value) {
	    StringValue sv = new StringValue();
	    sv.svalue = value;
	    return sv;
	}

	/**
	 * Converts a <code>StyleConstants</code> attribute value to
	 * a CSS attribute value.  If there is no conversion
	 * returns <code>null</code>. 
	 * 
	 * @param key the <code>StyleConstants</code> attribute
	 * @param value the value of a <code>StyleConstants</code>
	 *   attribute to be converted
	 * @return the CSS value that represents the 
         *   <code>StyleConstants</code> value
	 */
	Object fromStyleConstants(StyleConstants key, Object value) {
	    if (key == StyleConstants.Italic) {
		if (value.equals(Boolean.TRUE)) {
		    return parseCssValue("italic");
		}
		return parseCssValue("");
	    } else if (key == StyleConstants.Underline) {
		if (value.equals(Boolean.TRUE)) {
		    return parseCssValue("underline");
		} 
		return parseCssValue("");
	    } else if (key == StyleConstants.Alignment) {
		int align = ((Integer)value).intValue();
		String ta;
		switch(align) {
		case StyleConstants.ALIGN_LEFT:
		    ta = "left";
		    break;
		case StyleConstants.ALIGN_RIGHT:
		    ta = "right";
		    break;
		case StyleConstants.ALIGN_CENTER:
		    ta = "center";
		    break;
		case StyleConstants.ALIGN_JUSTIFIED:
		    ta = "justify";
		    break;
		default:
		    ta = "left";
		}
		return parseCssValue(ta);
	    } else if (key == StyleConstants.StrikeThrough) {
		if (value.equals(Boolean.TRUE)) {
		    return parseCssValue("line-through");
		} 
		return parseCssValue("");
	    } else if (key == StyleConstants.Superscript) {
		if (value.equals(Boolean.TRUE)) {
		    return parseCssValue("super");
		}
		return parseCssValue("");
	    } else if (key == StyleConstants.Subscript) {
		if (value.equals(Boolean.TRUE)) {
		    return parseCssValue("sub");
		}
		return parseCssValue("");
	    }
	    return null;
	}

	/**
	 * Converts a CSS attribute value to a 
         * <code>StyleConstants</code> value. 
         * If there is no conversion, returns <code>null</code>.
	 * By default, there is no conversion.
	 *
	 * @param key the <code>StyleConstants</code> attribute
	 * @return the <code>StyleConstants</code> attribute value that 
	 *   represents the CSS attribute value
	 */
	Object toStyleConstants(StyleConstants key, View v) {
	    if (key == StyleConstants.Italic) {
		if (svalue.indexOf("italic") >= 0) {
		    return Boolean.TRUE;
		}
		return Boolean.FALSE;
	    } else if (key == StyleConstants.Underline) {
		if (svalue.indexOf("underline") >= 0) {
		    return Boolean.TRUE;
		} 
		return Boolean.FALSE;
	    } else if (key == StyleConstants.Alignment) {
		if (svalue.equals("right")) {
		    return new Integer(StyleConstants.ALIGN_RIGHT);
		} else if (svalue.equals("center")) {
		    return new Integer(StyleConstants.ALIGN_CENTER);
		} else if  (svalue.equals("justify")) {
		    return new Integer(StyleConstants.ALIGN_JUSTIFIED);
		}
		return new Integer(StyleConstants.ALIGN_LEFT);
	    } else if (key == StyleConstants.StrikeThrough) {
		if (svalue.indexOf("line-through") >= 0) {
		    return Boolean.TRUE;
		} 
		return Boolean.FALSE;
	    } else if (key == StyleConstants.Superscript) {
		if (svalue.indexOf("super") >= 0) {
		    return Boolean.TRUE;
		} 
		return Boolean.FALSE;
	    } else if (key == StyleConstants.Subscript) {
		if (svalue.indexOf("sub") >= 0) {
		    return Boolean.TRUE;
		} 
		return Boolean.FALSE;
	    }
	    return null;
	}

	// Used by ViewAttributeSet
	boolean isItalic() {
	    return (svalue.indexOf("italic") != -1);
	}

	boolean isStrike() {
	    return (svalue.indexOf("line-through") != -1);
	}

	boolean isUnderline() {
	    return (svalue.indexOf("underline") != -1);
	}

	boolean isSub() {
	    return (svalue.indexOf("sub") != -1);
	}

	boolean isSup() {
	    return (svalue.indexOf("sup") != -1);
	}
    }

    /**
     * Represents a value for the CSS.FONT_SIZE attribute.
     * The binary format of the value can be one of several
     * types.  If the type is Float,
     * the value is specified in terms of point or
     * percentage, depending upon the ending of the
     * associated string.
     * If the type is Integer, the value is specified
     * in terms of a size index.
     */
    class FontSize extends CssValue {

	/**
	 * Returns the size in points.  This is ultimately
	 * what we need for the purpose of creating/fetching
	 * a Font object.
	 *
	 * @param a the attribute set the value is being
	 *  requested from.  We may need to walk up the
	 *  resolve hierarchy if it's relative.
	 */
	float getValue(AttributeSet a, StyleSheet ss) {
	    if (index) {
		// it's an index, translate from size table
		return getPointSize((int) value, ss);
	    }
	    else if (lu == null) {
		return value;
	    }
	    else {
		if (lu.type == 0) {
		    return lu.getValue(ss.isW3CLengthUnits());
		}
		if (a != null) {
		    AttributeSet resolveParent = a.getResolveParent();

		    if (resolveParent != null) {
			int pValue = StyleConstants.getFontSize(resolveParent);

			float retValue;
			if (lu.type == 1 || lu.type == 3) {
			    retValue = lu.value * (float)pValue;
			}
			else {
			    retValue = lu.value + (float)pValue;
			}
			return retValue;
		    }
		}
		// a is null, or no resolve parent.
		return 12;
	    }
	}

	Object parseCssValue(String value) {
	    FontSize fs = new FontSize();
	    fs.svalue = value;
	    try {
		if (value.equals("xx-small")) {
		    fs.value = 1;
		    fs.index = true;
		} else if (value.equals("x-small")) {
		    fs.value = 2;
		    fs.index = true;
		} else if (value.equals("small")) {
		    fs.value = 3;
		    fs.index = true;
		} else if (value.equals("medium")) {
		    fs.value = 4;
		    fs.index = true;
		} else if (value.equals("large")) {
		    fs.value = 5;
		    fs.index = true;
		} else if (value.equals("x-large")) {
		    fs.value = 6;
		    fs.index = true;
		} else if (value.equals("xx-large")) {
		    fs.value = 7;
		    fs.index = true;
		} else {
		    fs.lu = new LengthUnit(value, (short)1, 1f);
		}
		// relative sizes, larger | smaller (adjust from parent by
		// 1.5 pixels)
		// em, ex refer to parent sizes
		// lengths: pt, mm, cm, pc, in, px
		//          em (font height 3em would be 3 times font height)
		//          ex (height of X)
		// lengths are (+/-) followed by a number and two letter
		// unit identifier
	    } catch (NumberFormatException nfe) {
		fs = null;
	    }
	    return fs;
	}

	Object parseHtmlValue(String value) {
	    FontSize fs = new FontSize();
	    fs.svalue = value;

	    try {
		/*
		 * relative sizes in the size attribute are relative
		 * to the <basefont>'s size.
		 */
		int baseFontSize = getBaseFontSize();
		if ((value != null) && (value.charAt(0) == '+')) {
		    int relSize = Integer.valueOf(value.substring(1)).intValue();
		    fs.value = baseFontSize + relSize;
		    fs.index = true;
		} else if ((value != null) && (value.charAt(0) == '-')) {
		    int relSize = -Integer.valueOf(value.substring(1)).intValue();
		    fs.value = baseFontSize + relSize;
		    fs.index = true;
		} else {
		    fs.value = Integer.parseInt(value);
		    if (fs.value > 7) {
			fs.value = 7;
		    } else if (fs.value < 0) {
			fs.value = 0;
		    }
		    fs.index = true;
		}

	    } catch (NumberFormatException nfe) {
		fs = null;
	    }
	    return fs;
	}

	/**
	 * Converts a <code>StyleConstants</code> attribute value to
	 * a CSS attribute value.  If there is no conversion
	 * returns <code>null</code>.  By default, there is no conversion.
	 * 
	 * @param key the <code>StyleConstants</code> attribute
	 * @param value the value of a <code>StyleConstants</code>
	 *   attribute to be converted
	 * @return the CSS value that represents the 
         *   <code>StyleConstants</code> value
	 */
	Object fromStyleConstants(StyleConstants key, Object value) {
            if (value instanceof Number) {
                FontSize fs = new FontSize();

                fs.value = getIndexOfSize(((Number)value).floatValue(), StyleSheet.sizeMapDefault);
                fs.svalue = Integer.toString((int)fs.value);
                fs.index = true;
                return fs;
            }
            return parseCssValue(value.toString());
	}

	/**
	 * Converts a CSS attribute value to a <code>StyleConstants</code>
	 * value.  If there is no conversion, returns <code>null</code>.
	 * By default, there is no conversion.
	 *
	 * @param key the <code>StyleConstants</code> attribute
	 * @return the <code>StyleConstants</code> attribute value that 
	 *   represents the CSS attribute value
	 */
	Object toStyleConstants(StyleConstants key, View v) {
	    if (v != null) {
		return new Integer((int) getValue(v.getAttributes(), null));
	    }
	    return new Integer((int) getValue(null, null));
	}

	float value;
	boolean index;
	LengthUnit lu;
    }

    static class FontFamily extends CssValue {

	/**
	 * Returns the font family to use.  This is expected
	 * to be a legal font for this platform.
	 */
	String getValue() {
	    return family;
	}

	Object parseCssValue(String value) {
	    int cIndex = value.indexOf(',');
	    FontFamily ff = new FontFamily();
	    ff.svalue = value;
	    ff.family = null;

	    if (cIndex == -1) {
		setFontName(ff, value);
	    }
	    else {
		boolean done = false;
		int lastIndex;
		int length = value.length();
		cIndex = 0;
		while (!done) {
		    // skip ws.
		    while (cIndex < length &&
			   Character.isWhitespace(value.charAt(cIndex)))
			cIndex++;
		    // Find next ','
		    lastIndex = cIndex;
		    cIndex = value.indexOf(',', cIndex);
		    if (cIndex == -1) {
			cIndex = length;
		    }
		    if (lastIndex < length) {
			if (lastIndex != cIndex) {
			    int lastCharIndex = cIndex;
			    if (cIndex > 0 && value.charAt(cIndex - 1) == ' '){
				lastCharIndex--;
			    }
			    setFontName(ff, value.substring
					(lastIndex, lastCharIndex));
			    done = (ff.family != null);
			}
			cIndex++;
		    }
		    else {
			done = true;
		    }
		}
	    }
	    if (ff.family == null) {
		ff.family = "SansSerif";
	    }
	    return ff;
	}

	private void setFontName(FontFamily ff, String fontName) {
	    ff.family = (String)fontMapping.get(fontName);
	    if (ff.family != null) {
		return;
	    }
	    String lcFontName = mapFontName(fontName.toLowerCase());
	    Font f = new Font(lcFontName, Font.PLAIN, 12);
	    ff.family = f.getFamily();
	    if (ff.family.equals("Dialog") && !lcFontName.equals("dialog")) {
		ff.family = "SansSerif";
	    }
	    fontMapping.put(fontName, ff.family);
	}

	private String mapFontName(String name) {
	    if (name.equals("monospace")) {
		return "monospaced";
	    }
	    return name;
	}

	Object parseHtmlValue(String value) {
	    // TBD
	    return parseCssValue(value);
	}

	/**
	 * Converts a <code>StyleConstants</code> attribute value to
	 * a CSS attribute value.  If there is no conversion
	 * returns <code>null</code>.  By default, there is no conversion.
	 * 
	 * @param key the <code>StyleConstants</code> attribute
	 * @param value the value of a <code>StyleConstants</code>
	 *   attribute to be converted
	 * @return the CSS value that represents the 
         *   <code>StyleConstants</code> value
	 */
	Object fromStyleConstants(StyleConstants key, Object value) {
	    return parseCssValue(value.toString());
	}

	/**
	 * Converts a CSS attribute value to a <code>StyleConstants</code>
	 * value.  If there is no conversion, returns <code>null</code>.
	 * By default, there is no conversion.
	 *
	 * @param key the <code>StyleConstants</code> attribute
	 * @return the <code>StyleConstants</code> attribute value that 
	 *   represents the CSS attribute value
	 */
	Object toStyleConstants(StyleConstants key, View v) {
	    return family;
	}

	String family;
    }

    static class FontWeight extends CssValue {

	int getValue() {
	    return weight;
	}

	Object parseCssValue(String value) {
	    FontWeight fw = new FontWeight();
	    fw.svalue = value;
	    if (value.equals("bold")) {
		fw.weight = 700;
	    } else if (value.equals("normal")) {
		fw.weight = 400;
	    } else {
		// PENDING(prinz) add support for relative values
		try {
		    fw.weight = Integer.parseInt(value);
		} catch (NumberFormatException nfe) {
		    fw = null;
		}
	    }
	    return fw;
	}

	/**
	 * Converts a <code>StyleConstants</code> attribute value to
	 * a CSS attribute value.  If there is no conversion
	 * returns <code>null</code>.  By default, there is no conversion.
	 * 
	 * @param key the <code>StyleConstants</code> attribute
	 * @param value the value of a <code>StyleConstants</code>
	 *   attribute to be converted
	 * @return the CSS value that represents the 
         *   <code>StyleConstants</code> value
	 */
	Object fromStyleConstants(StyleConstants key, Object value) {
	    if (value.equals(Boolean.TRUE)) {
		return parseCssValue("bold");
	    }
	    return parseCssValue("normal");
	}

	/**
	 * Converts a CSS attribute value to a <code>StyleConstants</code>
	 * value.  If there is no conversion, returns <code>null</code>.
	 * By default, there is no conversion.
	 *
	 * @param key the <code>StyleConstants</code> attribute
	 * @return the <code>StyleConstants</code> attribute value that 
	 *   represents the CSS attribute value
	 */
	Object toStyleConstants(StyleConstants key, View v) {
	    return (weight > 500) ? Boolean.TRUE : Boolean.FALSE;
	}

	boolean isBold() {
	    return (weight > 500);
	}

	int weight;
    }

    static class ColorValue extends CssValue {

	/**
	 * Returns the color to use.
	 */
	Color getValue() {
	    return c;
	}

	Object parseCssValue(String value) {

	    Color c = stringToColor(value);
	    if (c != null) {
		ColorValue cv = new ColorValue();
		cv.svalue = value;
		cv.c = c;
		return cv;
	    }
	    return null;
	}

	Object parseHtmlValue(String value) {
	    return parseCssValue(value);
	}

	/**
	 * Converts a <code>StyleConstants</code> attribute value to
	 * a CSS attribute value.  If there is no conversion
	 * returns <code>null</code>.  By default, there is no conversion.
	 * 
	 * @param key the <code>StyleConstants</code> attribute
	 * @param value the value of a <code>StyleConstants</code>
	 *   attribute to be converted
	 * @return the CSS value that represents the 
         *   <code>StyleConstants</code> value
	 */
	Object fromStyleConstants(StyleConstants key, Object value) {
	    ColorValue colorValue = new ColorValue();
	    colorValue.c = (Color)value;
	    colorValue.svalue = colorToHex(colorValue.c);
	    return colorValue;
	}

	/**
	 * Converts a CSS attribute value to a <code>StyleConstants</code>
	 * value.  If there is no conversion, returns <code>null</code>.
	 * By default, there is no conversion.
	 *
	 * @param key the <code>StyleConstants</code> attribute
	 * @return the <code>StyleConstants</code> attribute value that 
	 *   represents the CSS attribute value
	 */
	Object toStyleConstants(StyleConstants key, View v) {
	    return c;
	}

	Color c;
    }

    static class BorderStyle extends CssValue {

	CSS.Value getValue() {
	    return style;
	}

	Object parseCssValue(String value) {
	    CSS.Value cssv = CSS.getValue(value);
	    if (cssv != null) {
		if ((cssv == CSS.Value.INSET) ||
		    (cssv == CSS.Value.OUTSET) ||
		    (cssv == CSS.Value.NONE) ||
		    (cssv == CSS.Value.DOTTED) ||
		    (cssv == CSS.Value.DASHED) ||
		    (cssv == CSS.Value.SOLID) ||
		    (cssv == CSS.Value.DOUBLE) ||
		    (cssv == CSS.Value.GROOVE) ||
		    (cssv == CSS.Value.RIDGE)) {

		    BorderStyle bs = new BorderStyle();
		    bs.svalue = value;
		    bs.style = cssv;
		    return bs;
		}
	    }
	    return null;
	}

	private void writeObject(java.io.ObjectOutputStream s)
	             throws IOException {
	    s.defaultWriteObject();
	    if (style == null) {
		s.writeObject(null);
	    }
	    else {
		s.writeObject(style.toString());
	    }
	}

	private void readObject(ObjectInputStream s)
		throws ClassNotFoundException, IOException {
	    s.defaultReadObject();
	    Object value = s.readObject();
	    if (value != null) {
		style = CSS.getValue((String)value);
	    }
	}

	// CSS.Values are static, don't archive it.
	transient private CSS.Value style;
    }

    static class LengthValue extends CssValue {

        /**
	 * if this length value may be negative.
	 */
	boolean mayBeNegative;

	LengthValue() {
	    this(false);
	}

	LengthValue(boolean mayBeNegative) {
	    this.mayBeNegative = mayBeNegative;
	}

	/**
	 * Returns the length (span) to use.
	 */
        float getValue() {
            return getValue(false);
        }

	float getValue(boolean isW3CLengthUnits) {
	    return getValue(0, isW3CLengthUnits);
	}
        
	/**
	 * Returns the length (span) to use. If the value represents
	 * a percentage, it is scaled based on <code>currentValue</code>.
	 */
	float getValue(float currentValue) {
            return getValue(currentValue, false);
        }
	float getValue(float currentValue, boolean isW3CLengthUnits) {
	    if (percentage) {
		return span * currentValue;
	    }
	    return LengthUnit.getValue(span, units, isW3CLengthUnits);
	}

	/**
	 * Returns true if the length represents a percentage of the
	 * containing box.
	 */
	boolean isPercentage() {
	    return percentage;
	}

	Object parseCssValue(String value) {
	    LengthValue lv;
	    try {
		// Assume pixels
		float absolute = Float.valueOf(value).floatValue();
		lv = new LengthValue();
		lv.span = absolute;
	    } catch (NumberFormatException nfe) {
		// Not pixels, use LengthUnit
		LengthUnit lu = new LengthUnit(value,
					       LengthUnit.UNINITALIZED_LENGTH,
					       0);

		// PENDING: currently, we only support absolute values and
		// percentages.
		switch (lu.type) {
		case 0:
		    // Absolute
		    lv = new LengthValue();
		    lv.span = 
			(mayBeNegative) ? lu.value : Math.max(0, lu.value);
                    lv.units = lu.units;
		    break;
		case 1:
		    // %
		    lv = new LengthValue();
		    lv.span = Math.max(0, Math.min(1, lu.value));
		    lv.percentage = true;
		    break;
		default:
		    return null;
		}
	    }
	    lv.svalue = value;
	    return lv;
	}

	Object parseHtmlValue(String value) {
	    if (value.equals(HTML.NULL_ATTRIBUTE_VALUE)) {
		value = "1";
	    }
	    return parseCssValue(value);
	}
	/**
	 * Converts a <code>StyleConstants</code> attribute value to
	 * a CSS attribute value.  If there is no conversion,
	 * returns <code>null</code>.  By default, there is no conversion.
	 * 
	 * @param key the <code>StyleConstants</code> attribute
	 * @param value the value of a <code>StyleConstants</code>
	 *   attribute to be converted
	 * @return the CSS value that represents the 
         *   <code>StyleConstants</code> value
	 */
	Object fromStyleConstants(StyleConstants key, Object value) {
	    LengthValue v = new LengthValue();
	    v.svalue = value.toString();
	    v.span = ((Float)value).floatValue();
	    return v;
	}

	/**
	 * Converts a CSS attribute value to a <code>StyleConstants</code>
	 * value.  If there is no conversion, returns <code>null</code>.
	 * By default, there is no conversion.
	 *
	 * @param key the <code>StyleConstants</code> attribute
	 * @return the <code>StyleConstants</code> attribute value that 
	 *   represents the CSS attribute value
	 */
	Object toStyleConstants(StyleConstants key, View v) {
 	    return new Float(getValue(false));
	}

	/** If true, span is a percentage value, and that to determine
	 * the length another value needs to be passed in. */
	boolean percentage;
	/** Either the absolute value (percentage == false) or 
	 * a percentage value. */
	float span;

        String units = null;
    }


    /**
     * BorderWidthValue is used to model BORDER_XXX_WIDTH and adds support
     * for the thin/medium/thick values.
     */
    static class BorderWidthValue extends LengthValue { 
	BorderWidthValue(String svalue, int index) {
	    this.svalue = svalue;
	    this.index = index;
	}

	float getValue() {
	    return values[index];
	}

	float getValue(float currentValue) {
	    return values[index];
	}

	Object parseCssValue(String value) {
	    if (value != null) {
		if (value.equals("thick")) {
		    return new BorderWidthValue(value, 2);
		}
		else if (value.equals("medium")) {
		    return new BorderWidthValue(value, 1);
		}
		else if (value.equals("thin")) {
		    return new BorderWidthValue(value, 0);
		}
	    }
	    // Assume its a length.
	    return super.parseCssValue(value);
	}

	Object parseHtmlValue(String value) {
	    if (value == HTML.NULL_ATTRIBUTE_VALUE) {
		return parseCssValue("medium");
	    }
	    return parseCssValue(value);
	}

	/** Index into values. */
	private int index;
	/** Values used to represent border width. */
	private static final float[] values = { 1, 2, 4 };
   }


    /**
     * Handles uniquing of CSS values, like lists, and background image
     * repeating.
     */
    static class CssValueMapper extends CssValue {
	Object parseCssValue(String value) {
	    Object retValue = cssValueToInternalValueMap.get(value);
	    if (retValue == null) {
		retValue = cssValueToInternalValueMap.get(value.toLowerCase());
	    }
	    return retValue;
	}


	Object parseHtmlValue(String value) {
	    Object retValue = htmlValueToCssValueMap.get(value);
	    if (retValue == null) {
		retValue = htmlValueToCssValueMap.get(value.toLowerCase());
	    }
	    return retValue;
	}
    }


    /**
     * Used for background images, to represent the position.
     */
    static class BackgroundPosition extends CssValue {
	float horizontalPosition;
	float verticalPosition;
	// bitmask: bit 0, horizontal relative, bit 1 horizontal relative to
	// font size, 2 vertical relative to size, 3 vertical relative to
	// font size.
	// 
	short relative;

	Object parseCssValue(String value) {
	    // 'top left' and 'left top' both mean the same as '0% 0%'. 
	    // 'top', 'top center' and 'center top' mean the same as '50% 0%'. 
	    // 'right top' and 'top right' mean the same as '100% 0%'. 
	    // 'left', 'left center' and 'center left' mean the same as
	    //        '0% 50%'. 
	    // 'center' and 'center center' mean the same as '50% 50%'. 
	    // 'right', 'right center' and 'center right' mean the same as 
	    //        '100% 50%'. 
	    // 'bottom left' and 'left bottom' mean the same as '0% 100%'. 
	    // 'bottom', 'bottom center' and 'center bottom' mean the same as
	    //        '50% 100%'. 
	    // 'bottom right' and 'right bottom' mean the same as '100% 100%'. 
	    String[]  strings = CSS.parseStrings(value);
	    int count = strings.length;
	    BackgroundPosition bp = new BackgroundPosition();
	    bp.relative = 5;
	    bp.svalue = value;

	    if (count > 0) {
		// bit 0 for vert, 1 hor, 2 for center
		short found = 0;
		int index = 0;
		while (index < count) {
		    // First, check for keywords
		    String string = strings[index++];
		    if (string.equals("center")) {
			found |= 4;
			continue;
		    }
		    else {
			if ((found & 1) == 0) {
			    if (string.equals("top")) {
				found |= 1;
			    }
			    else if (string.equals("bottom")) {
				found |= 1;
				bp.verticalPosition = 1;
				continue;
			    }
			}
			if ((found & 2) == 0) {
			    if (string.equals("left")) {
				found |= 2;
				bp.horizontalPosition = 0;
			    }
			    else if (string.equals("right")) {
				found |= 2;
				bp.horizontalPosition = 1;
			    }
			}
		    }
		}
		if (found != 0) {
		    if ((found & 1) == 1) {
			if ((found & 2) == 0) {
			    // vert and no horiz.
			    bp.horizontalPosition = .5f;
			}
		    }
		    else if ((found & 2) == 2) {
			// horiz and no vert.
			bp.verticalPosition = .5f;
		    }
		    else {
			// no horiz, no vert, but center
			bp.horizontalPosition = bp.verticalPosition = .5f;
		    }
		}
		else {
		    // Assume lengths
		    LengthUnit lu = new LengthUnit(strings[0], (short)0, 0f);

		    if (lu.type == 0) {
			bp.horizontalPosition = lu.value;
			bp.relative = (short)(1 ^ bp.relative);
		    }
		    else if (lu.type == 1) {
			bp.horizontalPosition = lu.value;
		    }
		    else if (lu.type == 3) {
			bp.horizontalPosition = lu.value;
			bp.relative = (short)((1 ^ bp.relative) | 2);
		    }
		    if (count > 1) {
			lu = new LengthUnit(strings[1], (short)0, 0f);

			if (lu.type == 0) {
			    bp.verticalPosition = lu.value;
			    bp.relative = (short)(4 ^ bp.relative);
			}
			else if (lu.type == 1) {
			    bp.verticalPosition = lu.value;
			}
			else if (lu.type == 3) {
			    bp.verticalPosition = lu.value;
			    bp.relative = (short)((4 ^ bp.relative) | 8);
			}
		    }
		    else {
			bp.verticalPosition = .5f;
		    }
		}
	    }
	    return bp;
	}

	boolean isHorizontalPositionRelativeToSize() {
	    return ((relative & 1) == 1);
	}

	boolean isHorizontalPositionRelativeToFontSize() {
	    return ((relative & 2) == 2);
	}

	float getHorizontalPosition() {
	    return horizontalPosition;
	}

	boolean isVerticalPositionRelativeToSize() {
	    return ((relative & 4) == 4);
	}

	boolean isVerticalPositionRelativeToFontSize() {
	    return ((relative & 8) == 8);
	}

	float getVerticalPosition() {
	    return verticalPosition;
	}
    }


    /**
     * Used for BackgroundImages.
     */
    static class BackgroundImage extends CssValue {
	private boolean    loadedImage;
	private ImageIcon  image;

	Object parseCssValue(String value) {
	    BackgroundImage retValue = new BackgroundImage();
	    retValue.svalue = value;
	    return retValue;
	}

	Object parseHtmlValue(String value) {
	    return parseCssValue(value);
	}

	// PENDING: this base is wrong for linked style sheets.
	ImageIcon getImage(URL base) {
	    if (!loadedImage) {
		synchronized(this) {
		    if (!loadedImage) {
			URL url = CSS.getURL(base, svalue);
			loadedImage = true;
			if (url != null) {
			    image = new ImageIcon(url);
			}
		    }
		}
	    }
	    return image;
	}
    }

    /**
     * Parses a length value, this is used internally, and never added
     * to an AttributeSet or returned to the developer.
     */
    static class LengthUnit implements Serializable {
	static Hashtable lengthMapping = new Hashtable(6);
        static Hashtable w3cLengthMapping = new Hashtable(6);
	static {
            lengthMapping.put("pt", new Float(1f)); 
            // Not sure about 1.3, determined by experiementation. 
            lengthMapping.put("px", new Float(1.3f)); 
            lengthMapping.put("mm", new Float(2.83464f)); 
            lengthMapping.put("cm", new Float(28.3464f)); 
            lengthMapping.put("pc", new Float(12f)); 
            lengthMapping.put("in", new Float(72f)); 
	    int res = 72;
            try {
                res = Toolkit.getDefaultToolkit().getScreenResolution();
            } catch (HeadlessException e) {
            }
	    // mapping according to the CSS2 spec
	    w3cLengthMapping.put("pt", new Float(res72f));
	    w3cLengthMapping.put("px", new Float(1f));
	    w3cLengthMapping.put("mm", new Float(res25.4f));
	    w3cLengthMapping.put("cm", new Float(res2.54f));
	    w3cLengthMapping.put("pc", new Float(res6f));
	    w3cLengthMapping.put("in", new Float(res));
	}

	LengthUnit(String value, short defaultType, float defaultValue) {
	    parse(value, defaultType, defaultValue);
	}

	void parse(String value, short defaultType, float defaultValue) {
	    type = defaultType;
	    this.value = defaultValue;

	    int length = value.length();
	    if (length > 0 && value.charAt(length - 1) == '%') {
		try {
		    this.value = Float.valueOf(value.substring(0, length - 1)).
			                       floatValue() / 100.0f;
		    type = 1;
		}
		catch (NumberFormatException nfe) { }
	    }
	    if (length >= 2) {
		units = value.substring(length - 2, length);
		Float scale = (Float)lengthMapping.get(units);
		if (scale != null) {
		    try {
			this.value = Float.valueOf(value.substring(0,
                               length - 2)).floatValue();
			type = 0;
		    }
		    catch (NumberFormatException nfe) { }
		}
		else if (units.equals("em") ||
			 units.equals("ex")) {
		    try {
			this.value = Float.valueOf(value.substring(0,
				      length - 2)).floatValue();
			type = 3;
		    }
		    catch (NumberFormatException nfe) { }
		}
		else if (value.equals("larger")) {
		    this.value = 2f;
		    type = 2;
		}
		else if (value.equals("smaller")) {
		    this.value = -2;
		    type = 2;
		}
		else {
		    // treat like points.
		    try {
			this.value = Float.valueOf(value).floatValue();
			type = 0;
		    } catch (NumberFormatException nfe) {}
		}
	    }
            else if (length > 0) {
                // treat like points.
                try {
                    this.value = Float.valueOf(value).floatValue();
                    type = 0;
                } catch (NumberFormatException nfe) {}
            }
	}

        float getValue(boolean w3cLengthUnits) {
            Hashtable mapping = (w3cLengthUnits) ? w3cLengthMapping : lengthMapping;
            float scale = 1;
            if (units != null) {
                Float scaleFloat = (Float)mapping.get(units);
                if (scaleFloat != null) {
                    scale = scaleFloat.floatValue();
                }
            }
            return this.value * scale;
            
        }
        
        static float getValue(float value, String units, Boolean w3cLengthUnits) {
            Hashtable mapping = (w3cLengthUnits) ? w3cLengthMapping : lengthMapping;
            float scale = 1;
            if (units != null) {
                Float scaleFloat = (Float)mapping.get(units);
                if (scaleFloat != null) {
                    scale = scaleFloat.floatValue();
                }
            }
            return value * scale;
        }
        
	public String toString() {
	    return type + " " + value;
	}

	// 0 - value indicates real value
	// 1 - % value, value relative to depends upon key.
	//     50% will have a value = .5
	// 2 - add value to parent value.
	// 3 - em/ex relative to font size of element (except for
	//     font-size, which is relative to parent).
	short type;
	float value;
        String units = null;
        

	static final short UNINITALIZED_LENGTH = (short)10;
    }


    /**
     * Class used to parse font property. The font property is shorthand
     * for the other font properties. This expands the properties, placing
     * them in the attributeset.
     */
    static class ShorthandFontParser {
	/**
	 * Parses the shorthand font string <code>value</code>, placing the
	 * result in <code>attr</code>.
	 */
	static void parseShorthandFont(CSS css, String value,
				       MutableAttributeSet attr) {
	    // font is of the form:
	    // [ <font-style> || <font-variant> || <font-weight> ]? <font-size>
	    //   [ / <line-height> ]? <font-family>
	    String[]   strings = CSS.parseStrings(value);
	    int        count = strings.length;
	    int        index = 0;
	    // bitmask, 1 for style, 2 for variant, 3 for weight
	    short      found = 0;
	    int        maxC = Math.min(3, count);

	    // Check for font-style font-variant font-weight
	    while (index < maxC) {
		if ((found & 1) == 0 && isFontStyle(strings[index])) {
		    css.addInternalCSSValue(attr, CSS.Attribute.FONT_STYLE,
					    strings[index++]);
		    found |= 1;
		}
		else if ((found & 2) == 0 && isFontVariant(strings[index])) {
		    css.addInternalCSSValue(attr, CSS.Attribute.FONT_VARIANT,
					    strings[index++]);
		    found |= 2;
		}
		else if ((found & 4) == 0 && isFontWeight(strings[index])) {
		    css.addInternalCSSValue(attr, CSS.Attribute.FONT_WEIGHT,
					    strings[index++]);
		    found |= 4;
		}
		else if (strings[index].equals("normal")) {
		    index++;
		}
		else {
		    break;
		}
	    }
	    if ((found & 1) == 0) {
		css.addInternalCSSValue(attr, CSS.Attribute.FONT_STYLE,
					"normal");
	    }
	    if ((found & 2) == 0) {
		css.addInternalCSSValue(attr, CSS.Attribute.FONT_VARIANT,
					"normal");
	    }
	    if ((found & 4) == 0) {
		css.addInternalCSSValue(attr, CSS.Attribute.FONT_WEIGHT,
					"normal");
	    }

	    // string at index should be the font-size
	    if (index < count) {
		String fontSize = strings[index];
		int slashIndex = fontSize.indexOf('/');

		if (slashIndex != -1) {
		    fontSize = fontSize.substring(0, slashIndex);
		    strings[index] = strings[index].substring(slashIndex);
		}
		else {
		    index++;
		}
		css.addInternalCSSValue(attr, CSS.Attribute.FONT_SIZE,
					fontSize);
	    }
	    else {
		css.addInternalCSSValue(attr, CSS.Attribute.FONT_SIZE,
					"medium");
	    }

	    // Check for line height
	    if (index < count && strings[index].startsWith("/")) {
		String lineHeight = null;
		if (strings[index].equals("/")) {
		    if (++index < count) {
			lineHeight = strings[index++];
		    }
		}
		else {
		    lineHeight = strings[index++].substring(1);
		}
		// line height
		if (lineHeight != null) {
		    css.addInternalCSSValue(attr, CSS.Attribute.LINE_HEIGHT,
					    lineHeight);
		}
		else {
		    css.addInternalCSSValue(attr, CSS.Attribute.LINE_HEIGHT,
					    "normal");
		}
	    }
	    else {
		css.addInternalCSSValue(attr, CSS.Attribute.LINE_HEIGHT,
					"normal");
	    }

	    // remainder of strings are font-family
	    if (index < count) {
		String family = strings[index++];

		while (index < count) {
		    family += " " + strings[index++];
		}
		css.addInternalCSSValue(attr, CSS.Attribute.FONT_FAMILY,
					family);
	    }
	    else {
		css.addInternalCSSValue(attr, CSS.Attribute.FONT_FAMILY,
					"SansSerif");
	    }
	}

	private static boolean isFontStyle(String string) {
	    return (string.equals("italic") ||
		    string.equals("oblique"));
	}

	private static boolean isFontVariant(String string) {
	    return (string.equals("small-caps"));
	}

	private static boolean isFontWeight(String string) {
	    if (string.equals("bold") || string.equals("bolder") ||
		string.equals("italic") || string.equals("lighter")) {
		return true;
	    }
	    // test for 100-900
	    return (string.length() == 3 &&
		    string.charAt(0) >= '1' && string.charAt(0) <= '9' &&
		    string.charAt(1) == '0' && string.charAt(2) == '0');
	}

    }


    /**
     * Parses the background property into its intrinsic values.
     */
    static class ShorthandBackgroundParser {
	/**
	 * Parses the shorthand font string <code>value</code>, placing the
	 * result in <code>attr</code>.
	 */
	static void parseShorthandBackground(CSS css, String value,
					     MutableAttributeSet attr) {
	    String[] strings = parseStrings(value);
	    int count = strings.length;
	    int index = 0;
	    // bitmask: 0 for image, 1 repeat, 2 attachment, 3 position,
	    //          4 color
	    short found = 0;

	    while (index < count) {
		String string = strings[index++];
		if ((found & 1) == 0 && isImage(string)) {
		    css.addInternalCSSValue(attr, CSS.Attribute.
					    BACKGROUND_IMAGE, string);
		    found |= 1;
		}
		else if ((found & 2) == 0 && isRepeat(string)) {
		    css.addInternalCSSValue(attr, CSS.Attribute.
					    BACKGROUND_REPEAT, string);
		    found |= 2;
		}
		else if ((found & 4) == 0 && isAttachment(string)) {
		    css.addInternalCSSValue(attr, CSS.Attribute.
					    BACKGROUND_ATTACHMENT, string);
		    found |= 4;
		}
		else if ((found & 8) == 0 && isPosition(string)) {
		    if (index < count && isPosition(strings[index])) {
			css.addInternalCSSValue(attr, CSS.Attribute.
						BACKGROUND_POSITION,
						string + " " +
						strings[index++]);
		    }
		    else {
			css.addInternalCSSValue(attr, CSS.Attribute.
						BACKGROUND_POSITION, string);
		    }
		    found |= 8;
		}
		else if ((found & 16) == 0 && isColor(string)) {
		    css.addInternalCSSValue(attr, CSS.Attribute.
					    BACKGROUND_COLOR, string);
		    found |= 16;
		}
	    }
	    if ((found & 1) == 0) {
		css.addInternalCSSValue(attr, CSS.Attribute.BACKGROUND_IMAGE,
					null);
	    }
	    if ((found & 2) == 0) {
		css.addInternalCSSValue(attr, CSS.Attribute.BACKGROUND_REPEAT,
					"repeat");
	    }
	    if ((found & 4) == 0) {
		css.addInternalCSSValue(attr, CSS.Attribute.
					BACKGROUND_ATTACHMENT, "scroll");
	    }
	    if ((found & 8) == 0) {
		css.addInternalCSSValue(attr, CSS.Attribute.
					BACKGROUND_POSITION, null);
	    }
	    // Currently, there is no good way to express this.
	    /*
	    if ((found & 16) == 0) {
		css.addInternalCSSValue(attr, CSS.Attribute.BACKGROUND_COLOR,
					null);
	    }
	    */
	}

	static boolean isImage(String string) {
	    return (string.startsWith("url(") && string.endsWith(")"));
	}

	static boolean isRepeat(String string) {
	    return (string.equals("repeat-x") || string.equals("repeat-y") ||
		    string.equals("repeat") || string.equals("no-repeat"));
	}

	static boolean isAttachment(String string) {
	    return (string.equals("fixed") || string.equals("scroll"));
	}

	static boolean isPosition(String string) {
	    return (string.equals("top") || string.equals("bottom") ||
		    string.equals("left") || string.equals("right") ||
		    string.equals("center") ||
		    (string.length() > 0 &&
		     Character.isDigit(string.charAt(0))));
	}

	static boolean isColor(String string) {
	    return (CSS.stringToColor(string) != null);
	}
    }


    /**
     * Used to parser margin and padding.
     */
    static class ShorthandMarginParser {
	/**
	 * Parses the shorthand margin/padding/border string
	 * <code>value</code>, placing the result in <code>attr</code>.
	 * <code>names</code> give the 4 instrinsic property names.
	 */
	static void parseShorthandMargin(CSS css, String value,
					 MutableAttributeSet attr,
					 CSS.Attribute[] names) {
	    String[] strings = parseStrings(value);
	    int count = strings.length;
	    int index = 0;
	    switch (count) {
	    case 0:
		// empty string
		return;
	    case 1:
		// Identifies all values.
		for (int counter = 0; counter < 4; counter++) {
		    css.addInternalCSSValue(attr, names[counter], strings[0]);
		}
		break;
	    case 2:
		// 0 & 2 = strings[0], 1 & 3 = strings[1]
		css.addInternalCSSValue(attr, names[0], strings[0]);
		css.addInternalCSSValue(attr, names[2], strings[0]);
		css.addInternalCSSValue(attr, names[1], strings[1]);
		css.addInternalCSSValue(attr, names[3], strings[1]);
		break;
	    case 3:
		css.addInternalCSSValue(attr, names[0], strings[0]);
		css.addInternalCSSValue(attr, names[1], strings[1]);
		css.addInternalCSSValue(attr, names[2], strings[2]);
		css.addInternalCSSValue(attr, names[3], strings[1]);
		break;
	    default:
		for (int counter = 0; counter < 4; counter++) {
		    css.addInternalCSSValue(attr, names[counter],
					    strings[counter]);
		}
		break;
	    }
	}
    }

    /**
     * Calculate the requirements needed to tile the requirements 
     * given by the iterator that would be tiled.  The calculation
     * takes into consideration margin and border spacing.
     */
    static SizeRequirements calculateTiledRequirements(LayoutIterator iter, SizeRequirements r) {
	long minimum = 0;
	long maximum = 0;
	long preferred = 0;
	int lastMargin = 0;
	int totalSpacing = 0;
	int n = iter.getCount();
	for (int i = 0; i < n; i++) {
	    iter.setIndex(i);
	    int margin0 = lastMargin;
	    int margin1 = (int) iter.getLeadingCollapseSpan();
	    totalSpacing += Math.max(margin0, margin1);;
	    preferred += (int) iter.getPreferredSpan(0);
	    minimum += iter.getMinimumSpan(0);
	    maximum += iter.getMaximumSpan(0);

	    lastMargin = (int) iter.getTrailingCollapseSpan();
	}
	totalSpacing += lastMargin;
	totalSpacing += 2 * iter.getBorderWidth();

	// adjust for the spacing area
	minimum += totalSpacing;
	preferred += totalSpacing;
	maximum += totalSpacing;

	// set return value
	if (r == null) {
	    r = new SizeRequirements();
	}
	r.minimum = (minimum > Integer.MAX_VALUE) ? Integer.MAX_VALUE : (int)minimum;
	r.preferred = (preferred > Integer.MAX_VALUE) ? Integer.MAX_VALUE :(int) preferred;
	r.maximum = (maximum > Integer.MAX_VALUE) ? Integer.MAX_VALUE :(int) maximum;
	return r;
    }

    /**
     * Calculate a tiled layout for the given iterator.
     * This should be done collapsing the neighboring
     * margins to be a total of the maximum of the two 
     * neighboring margin areas as described in the CSS spec.
     */
    static void calculateTiledLayout(LayoutIterator iter, int targetSpan) {
	
	/*
	 * first pass, calculate the preferred sizes, adjustments needed because
	 * of margin collapsing, and the flexibility to adjust the sizes.
	 */
	long preferred = 0;
	long currentPreferred = 0;
	int lastMargin = 0;
	int totalSpacing = 0;
	int n = iter.getCount();
	int adjustmentWeightsCount = LayoutIterator.WorstAdjustmentWeight + 1;
	//max gain we can get adjusting elements with adjustmentWeight <= i
	long gain[] = new long[adjustmentWeightsCount]; 
	//max loss we can get adjusting elements with adjustmentWeight <= i
	long loss[] = new long[adjustmentWeightsCount]; 

	for (int i = 0; i < adjustmentWeightsCount; i++) {
	    gain[i] = loss[i] = 0;
	}
	for (int i = 0; i < n; i++) {
	    iter.setIndex(i);
	    int margin0 = lastMargin;
	    int margin1 = (int) iter.getLeadingCollapseSpan();

	    iter.setOffset(Math.max(margin0, margin1));
	    totalSpacing += iter.getOffset();

	    currentPreferred = (long)iter.getPreferredSpan(targetSpan);
	    iter.setSpan((int) currentPreferred);
	    preferred += currentPreferred;
	    gain[iter.getAdjustmentWeight()] += 
		(long)iter.getMaximumSpan(targetSpan) - currentPreferred;
	    loss[iter.getAdjustmentWeight()] += 
		currentPreferred - (long)iter.getMinimumSpan(targetSpan);
	    lastMargin = (int) iter.getTrailingCollapseSpan();
	}
	totalSpacing += lastMargin;               
	totalSpacing += 2 * iter.getBorderWidth();	
	
	for (int i = 1; i < adjustmentWeightsCount; i++) {
	    gain[i] += gain[i - 1];
	    loss[i] += loss[i - 1];
	}

	/*
	 * Second pass, expand or contract by as much as possible to reach
	 * the target span.  This takes the margin collapsing into account
	 * prior to adjusting the span.
	 */

	// determine the adjustment to be made
	int allocated = targetSpan - totalSpacing;
	long desiredAdjustment = allocated - preferred;
	long adjustmentsArray[] = (desiredAdjustment > 0) ? gain : loss;
	desiredAdjustment = Math.abs(desiredAdjustment);
	int adjustmentLevel = 0;
	for (;adjustmentLevel <= LayoutIterator.WorstAdjustmentWeight; 
	     adjustmentLevel++) { 
	    // adjustmentsArray[] is sorted. I do not bother about
	    // binary search though
	    if (adjustmentsArray[adjustmentLevel] >= desiredAdjustment) {
		break;
	    }
	}
	float adjustmentFactor = 0.0f;
	if (adjustmentLevel <= LayoutIterator.WorstAdjustmentWeight) {
	    desiredAdjustment -= (adjustmentLevel > 0) ? 
		adjustmentsArray[adjustmentLevel - 1] : 0;
	    if (desiredAdjustment != 0) {
		float maximumAdjustment = 
		    adjustmentsArray[adjustmentLevel] - 
		    ((adjustmentLevel > 0) ? 
		     adjustmentsArray[adjustmentLevel - 1] : 0
		     );
		adjustmentFactor = desiredAdjustment / maximumAdjustment;
	    }
	}
	// make the adjustments
	int totalOffset = (int)iter.getBorderWidth();;
	for (int i = 0; i < n; i++) {
	    iter.setIndex(i);
	    iter.setOffset( iter.getOffset() + totalOffset);
	    if (iter.getAdjustmentWeight() < adjustmentLevel) {
		iter.setSpan((int)
			     ((allocated > preferred) ? 
			      Math.floor(iter.getMaximumSpan(targetSpan)) : 
			      Math.ceil(iter.getMinimumSpan(targetSpan))
			      )
			     );
	    } else if (iter.getAdjustmentWeight() == adjustmentLevel) {
		int availableSpan = (allocated > preferred) ? 
		    (int) iter.getMaximumSpan(targetSpan) - iter.getSpan() : 
		    iter.getSpan() - (int) iter.getMinimumSpan(targetSpan);
		int adj = (int)Math.floor(adjustmentFactor * availableSpan);
		iter.setSpan(iter.getSpan() + 
			     ((allocated > preferred) ? adj : -adj));
	    }
	    totalOffset = (int) Math.min((long) iter.getOffset() + 
					 (long) iter.getSpan(), 
					 Integer.MAX_VALUE);
	}

	// while rounding we could lose several pixels.
        int roundError = targetSpan - totalOffset - 
	    (int)iter.getTrailingCollapseSpan() - 
	    (int)iter.getBorderWidth();
	int adj = (roundError > 0) ? 1 : -1;
	roundError *= adj;

        boolean canAdjust = true;
        while (roundError > 0 && canAdjust) {
	    // check for infinite loop
	    canAdjust = false;
	    int offsetAdjust = 0;
	    // try to distribute roundError. one pixel per cell
	    for (int i = 0; i < n; i++) {
		iter.setIndex(i);
		iter.setOffset(iter.getOffset() + offsetAdjust);
                int curSpan = iter.getSpan();
                if (roundError > 0) {
		    int boundGap = (adj > 0) ? 
			(int)Math.floor(iter.getMaximumSpan(targetSpan)) - curSpan : 
			curSpan - (int)Math.ceil(iter.getMinimumSpan(targetSpan));
		    if (boundGap >= 1) {
			canAdjust = true;
			iter.setSpan(curSpan + adj);
			offsetAdjust += adj;
			roundError--;
		    }
                }
	    }
	}
    }

    /**
     * An iterator to express the requirements to use when computing
     * layout.
     */
    interface LayoutIterator {

	void setOffset(int offs);

	int getOffset();

	void setSpan(int span);

	int getSpan();

	int getCount();

	void setIndex(int i);

	float getMinimumSpan(float parentSpan);

	float getPreferredSpan(float parentSpan);

	float getMaximumSpan(float parentSpan);

	int getAdjustmentWeight(); //0 is the best weight WorstAdjustmentWeight is a worst one

	//float getAlignment();

	float getBorderWidth();

	float getLeadingCollapseSpan();  

	float getTrailingCollapseSpan();
	public static final int WorstAdjustmentWeight = 2;
    }

    //
    // Serialization support
    //

    private void writeObject(java.io.ObjectOutputStream s)
        throws IOException
    {
        s.defaultWriteObject();

	// Determine what values in valueConvertor need to be written out.
	Enumeration keys = valueConvertor.keys();
	s.writeInt(valueConvertor.size());
	if (keys != null) {
	    while (keys.hasMoreElements()) {
		Object key = keys.nextElement();
		Object value = valueConvertor.get(key);
		if (!(key instanceof Serializable) &&
		    (key = StyleContext.getStaticAttributeKey(key)) == null) {
		    // Should we throw an exception here?
		    key = null;
		    value = null;
		}
		else if (!(value instanceof Serializable) &&
		    (value = StyleContext.getStaticAttributeKey(value)) == null){
		    // Should we throw an exception here?
		    key = null;
		    value = null;
		}
		s.writeObject(key);
		s.writeObject(value);
	    }
	}
    }

    private void readObject(ObjectInputStream s)
      throws ClassNotFoundException, IOException 
    {
        s.defaultReadObject();
	// Reconstruct the hashtable.
	int numValues = s.readInt();
	valueConvertor = new Hashtable(Math.max(1, numValues));
	while (numValues-- > 0) {
	    Object key = s.readObject();
	    Object value = s.readObject();
	    Object staticKey = StyleContext.getStaticAttribute(key);
	    if (staticKey != null) {
		key = staticKey;
	    }
	    Object staticValue = StyleContext.getStaticAttribute(value);
	    if (staticValue != null) {
		value = staticValue;
	    }
	    if (key != null && value != null) {
		valueConvertor.put(key, value);
	    }
	}
    }

    //
    // Instance variables
    //

    /** Maps from CSS key to CssValue. */
    private transient Hashtable valueConvertor;

    /** Size used for relative units. */
    private int baseFontSize;

    static int baseFontSizeIndex = 3;
}