Newtonsoft.Json\Utilities\JavaScriptUtils.cs

#region License

// Copyright (c) 2007 James Newton-King

//

// Permission is hereby granted, free of charge, to any person

// obtaining a copy of this software and associated documentation

// files (the "Software"), to deal in the Software without

// restriction, including without limitation the rights to use,

// copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the

// Software is furnished to do so, subject to the following

// conditions:

//

// The above copyright notice and this permission notice shall be

// included in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

// OTHER DEALINGS IN THE SOFTWARE.

#endregion

using System;

using System.Collections;

using System.Globalization;

using System.IO;

using System.Text;

using System.Text.RegularExpressions;

using System.Collections.Generic;

namespace Newtonsoft.Json.Utilities

{

  internal static class JavaScriptUtils

  {

    public static void WriteEscapedJavaScriptString(TextWriter writer, string value, char delimiter, bool appendDelimiters)

    {

      // leading delimiter

      if (appendDelimiters)

        writer.Write(delimiter);

      if (value != null)

      {

        int lastWritePosition = 0;

        int skipped = 0;

        char[] chars = null;

        for (int i = 0; i < value.Length; i++)

        {

          char c = value[i];

          string escapedValue;

          switch (c)

          {

            case '\t':

              escapedValue = @"\t";

              break;

            case '\n':

              escapedValue = @"\n";

              break;

            case '\r':

              escapedValue = @"\r";

              break;

            case '\f':

              escapedValue = @"\f";

              break;

            case '\b':

              escapedValue = @"\b";

              break;

            case '\\':

              escapedValue = @"\\";

              break;

            case '\u0085': // Next Line

              escapedValue = @"\u0085";

              break;

            case '\u2028': // Line Separator

              escapedValue = @"\u2028";

              break;

            case '\u2029': // Paragraph Separator

              escapedValue = @"\u2029";

              break;

            case '\'':

              // only escape if this charater is being used as the delimiter

              escapedValue = (delimiter == '\'') ? @"\'" : null;

              break;

            case '"':

              // only escape if this charater is being used as the delimiter

              escapedValue = (delimiter == '"') ? "\\\"" : null;

              break;

            default:

              escapedValue = (c <= '\u001f') ? StringUtils.ToCharAsUnicode(c) : null;

              break;

          }

          if (escapedValue != null)

          {

            if (chars == null)

              chars = value.ToCharArray();

            // write skipped text

            if (skipped > 0)

            {

              writer.Write(chars, lastWritePosition, skipped);

              skipped = 0;

            }

            // write escaped value and note position

            writer.Write(escapedValue);

            lastWritePosition = i + 1;

          }

          else

          {

            skipped++;

          }

        }

        // write any remaining skipped text

        if (skipped > 0)

        {

          if (lastWritePosition == 0)

            writer.Write(value);

          else

            writer.Write(chars, lastWritePosition, skipped);

        }

      }

      // trailing delimiter

      if (appendDelimiters)

        writer.Write(delimiter);

    }

    public static string ToEscapedJavaScriptString(string value)

    {

      return ToEscapedJavaScriptString(value, '"', true);

    }

    public static string ToEscapedJavaScriptString(string value, char delimiter, bool appendDelimiters)

    {

      using (StringWriter w = StringUtils.CreateStringWriter(StringUtils.GetLength(value) ?? 16))

      {

        WriteEscapedJavaScriptString(w, value, delimiter, appendDelimiters);

        return w.ToString();

      }

    }

  }

}