JSONReader.cs :  » Content-Management-Systems-CMS » umbraco » umbraco » editorControls » tinyMCE3 » webcontrol » plugin » C# / CSharp Open Source

/*
 * $Id: JSONReader.cs 439 2007-11-26 13:26:10Z spocke $
 *
 * Copyright  2007, Moxiecode Systems AB, All rights reserved. 
 */

using System;
using System.IO;
using System.Text;
using System.Collections;

namespace umbraco.editorControls.tinyMCE3.webcontrol.plugin{
    /// <summary>
  /// 
  /// </summary>
  public enum JSONToken {
    /// <summary> </summary>
    Boolean,

    /// <summary> </summary>
    Integer,

    /// <summary> </summary>
    String,

    /// <summary> </summary>
    Null,

    /// <summary> </summary>
    Float,

    /// <summary> </summary>
    StartArray,

    /// <summary> </summary>
    EndArray,

    /// <summary> </summary>
    PropertyName,

    /// <summary> </summary>
    StartObject,

    /// <summary> </summary>
    EndObject
  }

  /// <summary>
  ///  Description of JSONReader.
  /// </summary>
  public class JSONReader {
    private TextReader reader;
    private JSONToken token;
    private object val;
    private JSONLocation location;
    private Stack lastLocations;
    private bool needProp;

    /// <summary>
    /// 
    /// </summary>
    /// <param name="reader"></param>
    public JSONReader(TextReader reader) {
      this.reader = reader;
      this.val = null;
      this.token = JSONToken.Null;
      this.location = JSONLocation.Normal;
      this.lastLocations = new Stack();
      this.needProp = false;
    }

    /// <summary>
    /// 
    /// </summary>
    public JSONLocation Location {
      get { return location; }
    }

    /// <summary>
    /// 
    /// </summary>
    public JSONToken TokenType {
      get {
        return this.token;
      }
    }

    /// <summary>
    /// 
    /// </summary>
    public object Value {
      get {
        return this.val;
      }
    }

    /// <summary>
    /// 
    /// </summary>
    /// <returns></returns>
    public bool Read() {
      int chr = this.reader.Read();

      if (chr != -1) {
        switch ((char) chr) {
          case '[':
            this.lastLocations.Push(this.location);
            this.location = JSONLocation.InArray;
            this.token = JSONToken.StartArray;
            this.val = null;
            this.ReadAway();
            return true;

          case ']':
            this.location = (JSONLocation) this.lastLocations.Pop();
            this.token = JSONToken.EndArray;
            this.val = null;
            this.ReadAway();

            if (this.location == JSONLocation.InObject)
              this.needProp = true;

            return true;

          case '{':
            this.lastLocations.Push(this.location);
            this.location = JSONLocation.InObject;
            this.needProp = true;
            this.token = JSONToken.StartObject;
            this.val = null;
            this.ReadAway();
            return true;

          case '}':
            this.location = (JSONLocation) this.lastLocations.Pop();
            this.token = JSONToken.EndObject;
            this.val = null;
            this.ReadAway();

            if (this.location == JSONLocation.InObject)
              this.needProp = true;

            return true;

          // String
          case '"':
          case '\'':
            return this.ReadString((char) chr);

          // Null
          case 'n':
            return this.ReadNull();

          // Bool
          case 't':
          case 'f':
            return this.ReadBool((char) chr);

          default:
            // Is number
            if (Char.IsNumber((char) chr) || (char) chr == '-' || (char) chr == '.')
              return this.ReadNumber((char) chr);

            return true;
        }
      }

      return false;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <returns></returns>
    public override string ToString() {
      switch (this.token) {
        case JSONToken.Boolean:
          return "[Boolean] = " + ((bool) this.Value ? "true" : "false");

        case JSONToken.EndArray:
          return "[EndArray]";

        case JSONToken.EndObject:
          return "[EndObject]";

        case JSONToken.Float:
          return "[Float] = " + Convert.ToDouble(this.Value);

        case JSONToken.Integer:
          return "[Integer] = " + ((int) this.Value);

        case JSONToken.Null:
          return "[Null]";

        case JSONToken.StartArray:
          return "[StartArray]";

        case JSONToken.StartObject:
          return "[StartObject]";

        case JSONToken.String:
          return "[String]" + (string) this.Value;

        case JSONToken.PropertyName:
          return "[PropertyName]" + (string) this.Value;
      }

      return base.ToString();
    }
    
    #region private methods

    private bool ReadString(char quote) {
      StringBuilder buff = new StringBuilder();
      this.token = JSONToken.String;
      bool endString = false;
      int chr;

      while ((chr = this.reader.Peek()) != -1) {
        switch (chr) {
          case '\\':
            // Read away slash
            chr = this.reader.Read();

            // Read escape code
            chr = this.reader.Read();
            switch (chr) {
                case 't':
                  buff.Append('\t');
                  break;

                case 'b':
                  buff.Append('\b');
                  break;

                case 'f':
                  buff.Append('\f');
                  break;

                case 'r':
                  buff.Append('\r');
                  break;

                case 'n':
                  buff.Append('\n');
                  break;

                case 'u':
                  buff.Append((char) Convert.ToInt32(ReadLen(4), 16));
                  break;

                default:
                  buff.Append((char) chr);
                  break;
            }

            break;

            case '\'':
            case '"':
              if (chr == quote)
                endString = true;

              chr = this.reader.Read();
              if (chr != -1 && chr != quote)
                buff.Append((char) chr);

              break;

            default:
              buff.Append((char) this.reader.Read());
              break;
        }

        // String terminated
        if (endString)
          break;
      }

      this.ReadAway();

      this.val = buff.ToString();

      // Needed a property
      if (this.needProp) {
        this.token = JSONToken.PropertyName;
        this.needProp = false;
        return true;
      }

      if (this.location == JSONLocation.InObject && !this.needProp)
        this.needProp = true;

      return true;
    }

    private bool ReadNull() {
      this.token = JSONToken.Null;
      this.val = null;

      this.ReadAway(3); // ull
      this.ReadAway();

      if (this.location == JSONLocation.InObject && !this.needProp)
        this.needProp = true;

      return true;
    }

    private bool ReadNumber(char start) {
      StringBuilder buff = new StringBuilder();
      int chr;
      bool isFloat = false;

      this.token = JSONToken.Integer;
      buff.Append(start);

      while ((chr = this.reader.Peek()) != -1) {
        if (Char.IsNumber((char) chr) || (char) chr == '-' || (char) chr == '.') {
          if (((char) chr) == '.')
            isFloat = true;

          buff.Append((char) this.reader.Read());
        } else
          break;
      }

      this.ReadAway();

      if (isFloat) {
        this.token = JSONToken.Float;
        this.val = Convert.ToDouble(buff.ToString().Replace('.', ','));
      } else
        this.val = Convert.ToInt32(buff.ToString());

      if (this.location == JSONLocation.InObject && !this.needProp)
        this.needProp = true;

      return true;
    }

    private bool ReadBool(char chr) {
      this.token = JSONToken.Boolean;
      this.val = chr == 't';

      if (chr == 't')
        this.ReadAway(3); // rue
      else
        this.ReadAway(4); // alse

      this.ReadAway();

      if (this.location == JSONLocation.InObject && !this.needProp)
        this.needProp = true;

      return true;
    }

    private void ReadAway() {
      int chr;
      
      while ((chr = this.reader.Peek()) != -1) {
        if (chr != ':' && chr != ',' && !Char.IsWhiteSpace((char) chr))
          break;

        this.reader.Read();
      }
    }

    private string ReadLen(int num) {
      StringBuilder buff = new StringBuilder();
      int chr;

      for (int i=0; i<num && (chr = this.reader.Read()) != -1; i++)
        buff.Append((char) chr);

      return buff.ToString();
    }
    
    private void ReadAway(int num) {
      for (int i=0; i<num && this.reader.Read() != -1; i++) ;
    }

    #endregion
  }
}