public JsonTextReader(TextReader reader)
{
if (reader == null)
{
throw new ArgumentNullException("reader");
}
_reader = new BufferedCharReader(reader);
Push(ParseMethod);
}
/// <summary>
/// Eats the next four characters, assuming hex digits, and converts
/// into the represented character value.
/// </summary>
/// <returns>The parsed character.</returns>
private static char ParseHex(BufferedCharReader input, char[] hexDigits)
{
Debug.Assert(input != null);
Debug.Assert(hexDigits != null);
Debug.Assert(hexDigits.Length == 4);
hexDigits[0] = input.Next();
hexDigits[1] = input.Next();
hexDigits[2] = input.Next();
hexDigits[3] = input.Next();
return((char)ushort.Parse(new string(hexDigits), NumberStyles.HexNumber));
}
/// <summary>
/// Reads the next token and returns it.
/// </summary>
protected override JsonToken ReadTokenImpl()
{
if (_stack == null)
{
return(JsonToken.EOF());
}
else if (_stack.Count == 0)
{
_stack = null;
_reader = null;
return(JsonToken.EOF());
}
else
{
return(Pop()());
}
}
internal static StringBuilder Dequote(BufferedCharReader input, char quote, StringBuilder output)
{
Debug.Assert(input != null);
if (output == null)
{
output = new StringBuilder();
}
char[] hexDigits = null;
while (true)
{
char ch = input.Next();
if (ch == BufferedCharReader.EOF)
{
throw new FormatException("Unterminated string.");
}
if (ch == '\\')
{
ch = input.Next();
switch (ch)
{
case 'b': output.Append('\b'); break; // Backspace
case 't': output.Append('\t'); break; // Horizontal tab
case 'n': output.Append('\n'); break; // Newline
case 'f': output.Append('\f'); break; // Form feed
case 'r': output.Append('\r'); break; // Carriage return
case 'u':
{
if (hexDigits == null)
{
hexDigits = new char[4];
}
output.Append(ParseHex(input, hexDigits));
break;
}
default:
output.Append(ch);
break;
}
}
else
{
if (ch == quote)
{
return(output);
}
output.Append(ch);
}
}
}
/// <summary>
/// Return the characters up to the next close quote character.
/// Backslash processing is done. The formal JSON format does not
/// allow strings in single quotes, but an implementation is allowed to
/// accept them.
/// </summary>
/// <param name="quote">The quoting character, either " or '</param>
/// <returns>A String.</returns>
// TODO: Consider rendering Dequote public
internal static string Dequote(BufferedCharReader input, char quote)
{
return(Dequote(input, quote, null).ToString());
}
