JavaScriptObjectDeserializer.cs :  » 2.6.4-mono-.net-core » System.Runtime » System » Runtime » Serialization » Json » C# / CSharp Open Source

using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Text;
using System.Xml;

namespace System.Runtime.Serialization.Json{
  internal partial class JavaScriptObjectDeserializer
  {
    #region stream/reader classes

    public class BufferedStreamReader : StreamReader
    {
      public BufferedStreamReader (Stream stream)
        : base (stream, JavaScriptObjectDeserializer.DetectEncoding (stream.ReadByte (), stream.ReadByte ()))
      {
      }
    }

    class BufferedStream : Stream
    {
      int first, second;
      long pos;
      Stream source;

      public BufferedStream (Stream source)
      {
        this.source = source;
        first = source.ReadByte ();
        second = source.ReadByte ();
      }

      public override int Read (byte [] buffer, int index, int count)
      {
        if (buffer == null)
          throw new ArgumentNullException ("buffer");
        if (index < 0 || index >= buffer.Length)
          throw new ArgumentOutOfRangeException ("index");
        if (count < 0 || index + count >= buffer.Length)
          throw new ArgumentOutOfRangeException ("count");

        if (count == 0)
          return 0;
        if (pos < 2) {
          buffer [pos] = pos == 0 ? (byte) first : (byte) second;
          pos++;
          return Read (buffer, index + 1, count - 1) + 1;
        }
        return source.Read (buffer, index, count);
      }

      public override int ReadByte ()
      {
        switch (pos) {
        case 0:
          pos++;
          return first;
        case 1:
          pos++;
          return second;
        default:
          return source.ReadByte ();
        }
      }

      public override bool CanRead {
        get { return source.CanRead; }
      }

      public override bool CanSeek {
        get { return false; }
      }

      public override bool CanWrite {
        get { return false; }
      }

      public override long Length {
        get { return source.Length; }
      }

      public override long Position {
        get { return source.Position; }
        set {
          if (value < 2)
            pos = value;
          source.Position = value;
        }
      }

      public override long Seek (long pos, SeekOrigin origin)
      {
        throw new NotSupportedException ();
      }

      public override void SetLength (long pos)
      {
        throw new NotSupportedException ();
      }

      public override void Write (byte [] buf, int index, int count)
      {
        throw new NotSupportedException ();
      }

      public override void Flush ()
      {
        // do nothing
      }
    }

    #endregion

    public JavaScriptObjectDeserializer (string json, bool raiseNumberParseError)
    {
      reader = new JavaScriptReader (new StringReader (json), raiseNumberParseError);
    }

    JavaScriptReader reader;

    public object BasicDeserialize ()
    {
      return reader.Read ();
    }

    public static Encoding DetectEncoding (int byte1, int byte2)
    {
      if (byte1 == 0) {
        if (byte2 == 0)
          throw new XmlException ("UTF-32BE is detected, which is not supported");
        else
          return Encoding.BigEndianUnicode;
      } else {
        if (byte2 == 0) // could be UTF-32LE, but there is no way to detect that only within two bytes.
          return Encoding.Unicode;
        else
          return Encoding.UTF8;
      }
    }
  }
}