// public static methods
/// <summary>
/// Gets the next JsonToken from a JsonBuffer.
/// </summary>
/// <param name="buffer">The buffer.</param>
/// <returns>The next token.</returns>
public static JsonToken GetNextToken(JsonBuffer buffer)
{
// skip leading whitespace
var c = buffer.Read();
while (c != -1 && char.IsWhiteSpace((char)c))
{
c = buffer.Read();
}
if (c == -1)
{
return new JsonToken(JsonTokenType.EndOfFile, "<eof>");
}
// leading character determines token type
switch (c)
{
case '{': return new JsonToken(JsonTokenType.BeginObject, "{");
case '}': return new JsonToken(JsonTokenType.EndObject, "}");
case '[': return new JsonToken(JsonTokenType.BeginArray, "[");
case ']': return new JsonToken(JsonTokenType.EndArray, "]");
case '(': return new JsonToken(JsonTokenType.LeftParen, "(");
case ')': return new JsonToken(JsonTokenType.RightParen, ")");
case ':': return new JsonToken(JsonTokenType.Colon, ":");
case ',': return new JsonToken(JsonTokenType.Comma, ",");
case '\'':
case '"':
return GetStringToken(buffer, (char)c);
case '/': return GetRegularExpressionToken(buffer);
default:
if (c == '-' || char.IsDigit((char)c))
{
return GetNumberToken(buffer, c);
}
else if (c == '$' || c == '_' || char.IsLetter((char)c))
{
return GetUnquotedStringToken(buffer);
}
else
{
buffer.UnRead(c);
throw new FileFormatException(FormatMessage("Invalid JSON input", buffer, buffer.Position));
}
}
}
private static JsonToken GetNumberToken(JsonBuffer buffer, int firstChar)
{
var c = firstChar;
// leading digit or '-' has already been read
var start = buffer.Position - 1;
NumberState state;
switch (c)
{
case '-': state = NumberState.SawLeadingMinus; break;
case '0': state = NumberState.SawLeadingZero; break;
default: state = NumberState.SawIntegerDigits; break;
}
var type = JsonTokenType.Int64; // assume integer until proved otherwise
while (true)
{
c = buffer.Read();
switch (state)
{
case NumberState.SawLeadingMinus:
switch (c)
{
case '0':
state = NumberState.SawLeadingZero;
break;
case 'I':
state = NumberState.SawMinusI;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawIntegerDigits;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawLeadingZero:
switch (c)
{
case '.':
state = NumberState.SawDecimalPoint;
break;
case 'e':
case 'E':
state = NumberState.SawExponentLetter;
break;
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawIntegerDigits:
switch (c)
{
case '.':
state = NumberState.SawDecimalPoint;
break;
case 'e':
case 'E':
state = NumberState.SawExponentLetter;
break;
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawIntegerDigits;
}
else if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawDecimalPoint:
type = JsonTokenType.Double;
if (char.IsDigit((char)c))
{
state = NumberState.SawFractionDigits;
}
else
{
state = NumberState.Invalid;
}
break;
case NumberState.SawFractionDigits:
switch (c)
{
case 'e':
case 'E':
state = NumberState.SawExponentLetter;
break;
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawFractionDigits;
}
else if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawExponentLetter:
type = JsonTokenType.Double;
switch (c)
{
case '+':
case '-':
state = NumberState.SawExponentSign;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawExponentDigits;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawExponentSign:
if (char.IsDigit((char)c))
{
state = NumberState.SawExponentDigits;
}
else
{
state = NumberState.Invalid;
}
break;
case NumberState.SawExponentDigits:
switch (c)
{
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawExponentDigits;
}
else if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawMinusI:
var sawMinusInfinity = true;
var nfinity = new char[] { 'n', 'f', 'i', 'n', 'i', 't', 'y' };
for (var i = 0; i < nfinity.Length; i++)
{
if (c != nfinity[i])
{
sawMinusInfinity = false;
break;
}
c = buffer.Read();
}
if (sawMinusInfinity)
{
type = JsonTokenType.Double;
switch (c)
{
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
}
else
{
state = NumberState.Invalid;
}
break;
}
switch (state)
{
case NumberState.Done:
buffer.UnRead(c);
var lexeme = buffer.Substring(start, buffer.Position - start);
if (type == JsonTokenType.Double)
{
var value = XmlConvert.ToDouble(lexeme);
return new DoubleJsonToken(lexeme, value);
}
else
{
var value = XmlConvert.ToInt64(lexeme);
if (value < int.MinValue || value > int.MaxValue)
{
return new Int64JsonToken(lexeme, value);
}
else
{
return new Int32JsonToken(lexeme, (int)value);
}
}
case NumberState.Invalid:
throw new FileFormatException(FormatMessage("Invalid JSON number", buffer, start));
}
}
}
private static JsonToken GetUnquotedStringToken(JsonBuffer buffer)
{
// opening letter or $ has already been read
var start = buffer.Position - 1;
var c = buffer.Read();
while (c == '$' || c == '_' || char.IsLetterOrDigit((char)c))
{
c = buffer.Read();
}
buffer.UnRead(c);
var lexeme = buffer.Substring(start, buffer.Position - start);
return new StringJsonToken(JsonTokenType.UnquotedString, lexeme, lexeme);
}
private static JsonToken GetRegularExpressionToken(JsonBuffer buffer)
{
// opening slash has already been read
var start = buffer.Position - 1;
var state = RegularExpressionState.InPattern;
while (true)
{
var c = buffer.Read();
switch (state)
{
case RegularExpressionState.InPattern:
switch (c)
{
case '/': state = RegularExpressionState.InOptions; break;
case '\\': state = RegularExpressionState.InEscapeSequence; break;
default: state = RegularExpressionState.InPattern; break;
}
break;
case RegularExpressionState.InEscapeSequence:
state = RegularExpressionState.InPattern;
break;
case RegularExpressionState.InOptions:
switch (c)
{
case 'i':
case 'm':
case 'x':
case 's':
state = RegularExpressionState.InOptions;
break;
case ',':
case '}':
case ']':
case ')':
case -1:
state = RegularExpressionState.Done;
break;
default:
if (char.IsWhiteSpace((char)c))
{
state = RegularExpressionState.Done;
}
else
{
state = RegularExpressionState.Invalid;
}
break;
}
break;
}
switch (state)
{
case RegularExpressionState.Done:
buffer.UnRead(c);
var lexeme = buffer.Substring(start, buffer.Position - start);
var regex = new BsonRegularExpression(lexeme);
return new RegularExpressionJsonToken(lexeme, regex);
case RegularExpressionState.Invalid:
throw new FileFormatException(FormatMessage("Invalid JSON regular expression", buffer, start));
}
}
}
private static JsonToken GetRegularExpressionToken(JsonBuffer buffer)
{
// opening slash has already been read
var start = buffer.Position - 1;
var state = RegularExpressionState.InPattern;
while (true)
{
var c = buffer.Read();
switch (state)
{
case RegularExpressionState.InPattern:
switch (c)
{
case '/': state = RegularExpressionState.InOptions; break;
case '\\': state = RegularExpressionState.InEscapeSequence; break;
default: state = RegularExpressionState.InPattern; break;
}
break;
case RegularExpressionState.InEscapeSequence:
state = RegularExpressionState.InPattern;
break;
case RegularExpressionState.InOptions:
switch (c)
{
case 'i':
case 'm':
case 'x':
case 's':
state = RegularExpressionState.InOptions;
break;
case ',':
case '}':
case ']':
case ')':
case -1:
state = RegularExpressionState.Done;
break;
default:
if (char.IsWhiteSpace((char)c))
{
state = RegularExpressionState.Done;
}
else
{
state = RegularExpressionState.Invalid;
}
break;
}
break;
}
switch (state)
{
case RegularExpressionState.Done:
buffer.UnRead(c);
var lexeme = buffer.Substring(start, buffer.Position - start);
var regex = new BsonRegularExpression(lexeme);
return(new RegularExpressionJsonToken(lexeme, regex));
case RegularExpressionState.Invalid:
throw new FileFormatException(FormatMessage("Invalid JSON regular expression", buffer, start));
}
}
}
private static JsonToken GetNumberToken(JsonBuffer buffer, int firstChar)
{
var c = firstChar;
// leading digit or '-' has already been read
var start = buffer.Position - 1;
NumberState state;
switch (c)
{
case '-': state = NumberState.SawLeadingMinus; break;
case '0': state = NumberState.SawLeadingZero; break;
default: state = NumberState.SawIntegerDigits; break;
}
var type = JsonTokenType.Int64; // assume integer until proved otherwise
while (true)
{
c = buffer.Read();
switch (state)
{
case NumberState.SawLeadingMinus:
switch (c)
{
case '0':
state = NumberState.SawLeadingZero;
break;
case 'I':
state = NumberState.SawMinusI;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawIntegerDigits;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawLeadingZero:
switch (c)
{
case '.':
state = NumberState.SawDecimalPoint;
break;
case 'e':
case 'E':
state = NumberState.SawExponentLetter;
break;
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawIntegerDigits:
switch (c)
{
case '.':
state = NumberState.SawDecimalPoint;
break;
case 'e':
case 'E':
state = NumberState.SawExponentLetter;
break;
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawIntegerDigits;
}
else if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawDecimalPoint:
type = JsonTokenType.Double;
if (char.IsDigit((char)c))
{
state = NumberState.SawFractionDigits;
}
else
{
state = NumberState.Invalid;
}
break;
case NumberState.SawFractionDigits:
switch (c)
{
case 'e':
case 'E':
state = NumberState.SawExponentLetter;
break;
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawFractionDigits;
}
else if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawExponentLetter:
type = JsonTokenType.Double;
switch (c)
{
case '+':
case '-':
state = NumberState.SawExponentSign;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawExponentDigits;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawExponentSign:
if (char.IsDigit((char)c))
{
state = NumberState.SawExponentDigits;
}
else
{
state = NumberState.Invalid;
}
break;
case NumberState.SawExponentDigits:
switch (c)
{
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsDigit((char)c))
{
state = NumberState.SawExponentDigits;
}
else if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
break;
case NumberState.SawMinusI:
var sawMinusInfinity = true;
var nfinity = new char[] { 'n', 'f', 'i', 'n', 'i', 't', 'y' };
for (var i = 0; i < nfinity.Length; i++)
{
if (c != nfinity[i])
{
sawMinusInfinity = false;
break;
}
c = buffer.Read();
}
if (sawMinusInfinity)
{
type = JsonTokenType.Double;
switch (c)
{
case ',':
case '}':
case ']':
case ')':
case -1:
state = NumberState.Done;
break;
default:
if (char.IsWhiteSpace((char)c))
{
state = NumberState.Done;
}
else
{
state = NumberState.Invalid;
}
break;
}
}
else
{
state = NumberState.Invalid;
}
break;
}
switch (state)
{
case NumberState.Done:
buffer.UnRead(c);
var lexeme = buffer.Substring(start, buffer.Position - start);
if (type == JsonTokenType.Double)
{
var value = XmlConvert.ToDouble(lexeme);
return(new DoubleJsonToken(lexeme, value));
}
else
{
var value = XmlConvert.ToInt64(lexeme);
if (value < int.MinValue || value > int.MaxValue)
{
return(new Int64JsonToken(lexeme, value));
}
else
{
return(new Int32JsonToken(lexeme, (int)value));
}
}
case NumberState.Invalid:
throw new FileFormatException(FormatMessage("Invalid JSON number", buffer, start));
}
}
}