private void AssertExpected(AllowedToken match)
{
if ((_expected & match) == 0)
{
ParseException("Expected a " + string.Join(", ", Definition(_expected).ToArray())
+ ", but found a "
+ string.Join(", ", Definition(match).ToArray()));
}
}
private static IEnumerable <string> Definition(AllowedToken match)
{
var parts = new List <string>();
if ((match & AllowedToken.Array) != 0)
{
parts.Add("`[`");
}
if ((match & AllowedToken.Boolean) != 0)
{
parts.Add("boolean");
}
if ((match & AllowedToken.Colon) != 0)
{
parts.Add("`:`");
}
if ((match & AllowedToken.Comma) != 0)
{
parts.Add("`,`");
}
if ((match & AllowedToken.EndObject) != 0)
{
parts.Add("`}`");
}
if ((match & AllowedToken.EndArray) != 0)
{
parts.Add("`]`");
}
if ((match & AllowedToken.Null) != 0)
{
parts.Add("`null`");
}
if ((match & AllowedToken.Number) != 0)
{
parts.Add("number");
}
if ((match & AllowedToken.Object) != 0)
{
parts.Add("`{`");
}
if ((match & AllowedToken.Property) != 0)
{
parts.Add("property name");
}
if ((match & AllowedToken.String) != 0)
{
parts.Add("string");
}
return(parts);
}
public bool Read()
{
SkipWhitespace();
var next = Peek();
if (next == ':' && (_expected & AllowedToken.Colon) != 0)
{
ReadChar();
_expected = AllowedToken.Value;
SkipWhitespace();
next = Peek();
}
else if (next == ',' && (_expected & AllowedToken.Comma) != 0 && _groups.Count > 0)
{
ReadChar();
_expected = _groups.Peek() == JsonToken.StartObject ? AllowedToken.Property : AllowedToken.Value;
SkipWhitespace();
next = Peek();
}
switch (next)
{
case '{':
AssertExpected(AllowedToken.Object);
_expected = AllowedToken.Property | AllowedToken.EndObject;
TokenType = JsonToken.StartObject;
Value = null;
ReadChar();
_groups.Push(TokenType);
return(true);
case '[':
AssertExpected(AllowedToken.Array);
_expected = AllowedToken.Value | AllowedToken.EndArray;
TokenType = JsonToken.StartArray;
Value = null;
ReadChar();
_groups.Push(TokenType);
return(true);
case '}':
if (_groups.Count < 1)
{
ParseException($"Too many closing `{next}`");
}
var open = _groups.Pop();
if (open != JsonToken.StartObject)
{
ParseException($"Closing character `{next}` does not match the last opening character `{Definition(open)}`");
}
AssertExpected(AllowedToken.EndObject);
_expected = AllowedToken.EndValue;
TokenType = JsonToken.EndObject;
Value = null;
ReadChar();
return(true);
case ']':
if (_groups.Count < 1)
{
ParseException($"Too many closing `{next}`");
}
var open2 = _groups.Pop();
if (open2 != JsonToken.StartArray)
{
ParseException($"Closing character `{next}` does not match the last opening character `{Definition(open2)}`");
}
AssertExpected(AllowedToken.EndArray);
_expected = AllowedToken.EndValue;
TokenType = JsonToken.EndArray;
Value = null;
ReadChar();
return(true);
case '"':
AssertExpected(AllowedToken.Property | AllowedToken.String);
Value = ReadString();
if ((_expected & AllowedToken.Property) != 0)
{
TokenType = JsonToken.PropertyName;
_expected = AllowedToken.Colon;
}
else
{
TokenType = JsonToken.String;
_expected = AllowedToken.EndValue;
}
return(true);
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
case '-':
AssertExpected(AllowedToken.Number);
_expected = AllowedToken.EndValue;
TokenType = JsonToken.Number;
Value = ReadNumber();
return(true);
case 't':
case 'f':
AssertExpected(AllowedToken.Boolean);
_expected = AllowedToken.EndValue;
TokenType = JsonToken.Boolean;
Value = ReadBoolean();
return(true);
case 'n':
AssertExpected(AllowedToken.Null);
_expected = AllowedToken.EndValue;
TokenType = JsonToken.Null;
Value = ReadNull();
return(true);
case '\0':
if (_groups.Count > 0)
{
ParseException($"The last group `{Definition(_groups.Peek())}` is not closed");
}
TokenType = JsonToken.None;
Value = null;
return(false);
default:
ParseException();
return(false);
}
}
