source: branches/HeuristicLab.Problems.GrammaticalOptimization/SharpVectorCss/Css/CssValue.cs @ 13398

// <developer>niklas@protocol7.com</developer>
// <completed>80</completed>

using System;
using System.Xml;
using System.Globalization;
using System.Text.RegularExpressions;

namespace SharpVectors.Dom.Css
{
  /// <summary>
  /// The CSSValue interface represents a simple or a complex value. A CSSValue object only occurs in a context of a CSS property
  /// </summary>
  public class CssValue : ICssValue
  {
    #region Static members
    private static string numberPattern = @"[\-\+]?[0-9]*\.?[0-9]+";
    public static string LengthUnitPattern = "(?<lengthUnit>in|cm|mm|px|em|ex|pc|pt|%)?";
    public static string AngleUnitPattern = "(?<angleUnit>deg|rad|grad)?";
    public static string LengthPattern = @"(?<lengthNumber>" + numberPattern + ")" + LengthUnitPattern;
    public static string AnglePattern = @"(?<angleNumber>" + numberPattern + ")" + AngleUnitPattern;

    private static string cssPrimValuePattern = @"^(?<primitiveValue>" 
      + @"(?<func>(?<funcname>attr|url|counter|rect|rgb)\((?<funcvalue>[^\)]+)\))"
      + @"|(?<length>" + LengthPattern + ")"
      + @"|(?<angle>" + AnglePattern + ")"
      + @"|(?<freqTimeNumber>(?<numberValue2>" + numberPattern + ")(?<unit2>Hz|kHz|in|s|ms|%)?)"
      + @"|(?<string>[""'](?<stringvalue>(.|\n)*?)[""'])"
      + @"|(?<colorIdent>([A-Za-z]+)|(\#[A-Fa-f0-9]{6})|(\#[A-Fa-f0-9]{3}))"
      + @")";

    private static Regex reCssPrimitiveValue = new Regex(cssPrimValuePattern + "$");
    private static Regex reCssValueList = new Regex(cssPrimValuePattern + @"(\s*,\s*)+$");

    /// <summary>
    /// Detects what kind of value cssText contains and returns an instance of the correct CssValue class
    /// </summary>
    /// <param name="cssText">The text to parse for a CSS value</param>
    /// <param name="readOnly">Specifies if this instance is read-only</param>
    /// <returns>The correct type of CSS value</returns>
    static public CssValue GetCssValue(string cssText, bool readOnly)
    {
      if(cssText == "inherit")
      {
        // inherit
        return new CssValue(CssValueType.Inherit, cssText, readOnly);
      }
      else
      {
        Match match = reCssPrimitiveValue.Match(cssText);
        if(match.Success)
        {
          // single primitive value
          return CssPrimitiveValue.Create(match, readOnly);
        }
        
        match = reCssValueList.Match(cssText);
        if(match.Success)
        {
          // list of primitive values
          throw new NotImplementedException("Value lists not implemented");
        }
        else
        {
          // custom value
          return new CssValue(CssValueType.Custom, cssText, readOnly);
        }
      }
    }
    #endregion

    #region Constructors
    /// <summary>
    /// Constructor for CssValue
    /// </summary>
    /// <param name="type">The type of value</param>
    /// <param name="cssText">The entire content of the value</param>
    /// <param name="readOnly">Specifies if the instance is read-only</param>
    public CssValue(CssValueType type, string cssText, bool readOnly)
    {
      _cssText = cssText.Trim();
      _cssValueType = type;
      _readOnly = readOnly;
    }

    /// <summary>
    /// Only for internal use
    /// </summary>
    protected CssValue()
    {
      _readOnly = true;
    }
    #endregion

    #region Public methods
    public virtual CssValue GetAbsoluteValue(string propertyName, XmlElement elm)
    {
      return new CssAbsValue(this, propertyName, elm);
    }
    #endregion

    private bool _readOnly;
    public virtual bool ReadOnly
    {
      get
      {
        return _readOnly;
      }
    }

    #region ICssValue Members

    private string _cssText;
        protected CssValueType _cssValueType;

    /// <summary>
    /// A string representation of the current value.
    /// </summary>
    /// <exception cref="DomException">SYNTAX_ERR: Raised if the specified CSS string value has a syntax error (according to the attached property) or is unparsable.</exception>
    /// <exception cref="DomException">INVALID_MODIFICATION_ERR: Raised if the specified CSS string value represents a different type of values than the values allowed by the CSS property</exception>
    /// <exception cref="DomException">NO_MODIFICATION_ALLOWED_ERR: Raised if this value is readonly.</exception>
    public virtual string CssText
    {
      get
      {
        return _cssText;
      }
      set
      {
        if(ReadOnly)
        {
          throw new DomException(DomExceptionType.InvalidModificationErr, "The CssValue is read-only");
        }
        else
        {
          _cssText = value;
        }
      }
    }

    /// <summary>
    /// A code defining the type of the value as defined above
    /// </summary>
    public virtual CssValueType CssValueType
    {
      get
      {
        return _cssValueType;
      }
    }

    #endregion
  }
}