source: branches/HeuristicLab.Problems.GrammaticalOptimization/SharpVectorCss/Stylesheets/MediaList.cs @ 12762

// <developer>niklas@protocol7.com</developer>
// <completed>75</completed>

using System;
using System.Collections.Generic;
using System.Text.RegularExpressions;

namespace SharpVectors.Dom.Stylesheets
{
  /// <summary>
  /// The MediaList interface provides the abstraction of an ordered collection of media, without defining or constraining how this collection is implemented. An empty list is the same as a list that contains the medium "all".
  /// The items in the MediaList are accessible via an integral index, starting from 0.
  /// </summary>
  public sealed class MediaList : IMediaList
  {
    private static Regex splitter = new Regex(@"\s*,\s*");

    #region Constructors
    public MediaList() : this(String.Empty)
    {
    }

    public MediaList(string val)
    {
      _parseString(val);
    }
    #endregion

    private void _parseString(string mediaText)
    {
      mediaText = mediaText.Trim();
      if(mediaText.Length > 0)
      {
        string[] ms = splitter.Split(mediaText);
        foreach(string m in ms)
        {
          AppendMedium(m);
        }
      }
    }

    private void _clear()
    {
      medias.Clear();
    }

    #region Public methods
    /// <summary>
    /// Compares this MediaList with another and see if the second fits this
    /// </summary>
    /// <param name="inMedia">The MediaList to compare</param>
    /// <returns>True if this list fits the specified</returns>
    public bool Matches(MediaList inMedia)
    {
      if(inMedia.Length == 0) return false;
      else if(Length == 0 || containsAll)
      {
        // is empty or this list contains "all"
        return true;
      }
      else
      {
        for(ulong i = 0; i<inMedia.Length; i++)
        {
          if (medias.Contains(inMedia[i])) 
                        return true;
        }
      }
      return false;
    }

    #endregion

    #region Private fields
    private bool containsAll = false; //speeds up matching if the list contains "all"
        private List<string> medias = new List<string>();
    #endregion

    #region Implementation of IMediaList
    /// <summary>
    /// Adds the medium newMedium to the end of the list. If the newMedium is already used, it is first removed.
    /// </summary>
    /// <param name="newMedium">The new medium to add.</param>
    /// <exception cref="DomException">INVALID_CHARACTER_ERR: If the medium contains characters that are invalid in the underlying style language.</exception>
    /// <exception cref="DomException">NO_MODIFICATION_ALLOWED_ERR: Raised if this media list is readonly.</exception>
    public void AppendMedium(string newMedium)
    {
      if (newMedium.Length > 0)
      {
        medias.Remove(newMedium);
        medias.Add(newMedium);
        if (newMedium.Equals("all")) 
                    containsAll = true;
      }
    }

    /// <summary>
    /// Deletes the medium indicated by oldMedium from the list.
    /// </summary>
    /// <param name="oldMedium">The medium to delete in the media list.</param>
    /// <exception cref="DomException">NOT_FOUND_ERR: Raised if oldMedium is not in the list.</exception>
    /// <exception cref="DomException">NO_MODIFICATION_ALLOWED_ERR: Raised if this media list is readonly.</exception>
    public void DeleteMedium(string oldMedium)
    {
      if(oldMedium == "all") containsAll = false;
      medias.Remove(oldMedium);
    }

    /// <summary>
    /// The number of media in the list. The range of valid media is 0 to length-1 inclusive.
    /// </summary>
    public ulong Length
    {
      get
      {
        return (ulong)medias.Count;
      }
    }

    /// <summary>
    /// The parsable textual representation of the media list. This is a comma-separated list of media.
    /// </summary>
    /// <exception cref="DomException">SYNTAX_ERR: Raised if the specified string value has a syntax error and is unparsable.</exception>
    /// <exception cref="DomException">NO_MODIFICATION_ALLOWED_ERR: Raised if this media list is readonly.</exception>
    public string MediaText
    {
      get
      {
        string result = String.Empty;
        foreach(string media in medias)
        {
          result += media + ",";
        }
        if(result.Length > 0)
        {
          result = result.Substring(0, result.Length-1);
        }
        return result;
      }
      set
      {
        _clear();
        _parseString(value);
      }
    }

    /// <summary>
    /// Returns the indexth in the list. If index is greater than or equal to the number of media in the list, this returns null.
    /// </summary>
    public string this[ulong index]
    {
      get
      {
        return (index < Length) ? medias[(int)index] : null;
      }
    }

    #endregion
  }
}