private static void Shift(Stack<int> shiftReduceStack, JsonLexicalAnalyzer lex, JsonLexicalType currentLexeme, ShiftReduce shiftReduce, Stack<IJsonValue> inputStack)
{
shiftReduceStack.Push((int)currentLexeme);
shiftReduceStack.Push(shiftReduce.Action);
//if (Log.IsDebugEnabled)
// Log.Debug("Shift {0} s{1}", currentLexeme, shiftReduce.Action);
switch (currentLexeme)
{
case JsonLexicalType.Number:
if (lex.CurrentDouble.HasValue)
inputStack.Push(new JsonNumber(lex.CurrentDouble.Value));
else if (lex.CurrentInt64.HasValue)
inputStack.Push(new JsonNumber(lex.CurrentInt64.Value));
break;
case JsonLexicalType.String:
inputStack.Push(new JsonString(lex.CurrentString));
break;
case JsonLexicalType.True:
inputStack.Push(new JsonBoolean(true));
break;
case JsonLexicalType.False:
inputStack.Push(new JsonBoolean(false));
break;
case JsonLexicalType.Null:
inputStack.Push(Singleton<JsonNull>.Instance);
break;
default:
break;
}
}
private static IJsonValue ShiftReduceParse(string json, JsonLexicalAnalyzer lex)
{
var inputStack = new Stack<IJsonValue>();
var parseStack = new Stack<ParseItem>();
var shiftReduceStack = new Stack<int>();
shiftReduceStack.Push(0);
var currentLexeme = lex.Scan();
var done = false;
while (!done)
{
if (currentLexeme == JsonLexicalType.Error)
LogAndThrowJsonError(lex, json, false);
var topOfStack = shiftReduceStack.Peek();
var shiftReduceAction = ActionGotoTable[topOfStack, (int)currentLexeme];
switch (shiftReduceAction.Type)
{
case ShiftReduceType.Shift:
Shift(shiftReduceStack, lex, currentLexeme, shiftReduceAction, inputStack);
currentLexeme = lex.Scan();
break;
case ShiftReduceType.Reduce:
Reduce(shiftReduceStack, shiftReduceAction, inputStack, parseStack);
break;
case ShiftReduceType.Accept:
if (Log.IsDebugEnabled)
Log.Debug("JSON Parser Accept State");
done = true;
break;
default:
LogAndThrowJsonError(lex, json, true);
break;
}
}
// ParseRoot should always be left on the parseStack at this point (otherwise an error would have already occured)
return parseStack.Pop().ToJsonValue();
}
private static void LogAndThrowJsonError(JsonLexicalAnalyzer lex, string json, bool isParseError)
{
var parseAnalysisError = isParseError ? "parsing" : "analyzing";
var errorMessage = string.Format("Error {3} JSON at line number {1} character {2}: {0}", json, lex.LineNumber, lex.Index, parseAnalysisError);
if (Log.IsErrorEnabled)
Log.Error(errorMessage);
throw new JsonException(errorMessage);
}
/// <summary>
/// Parses a JSON string to create an IJsonValue representation of the JSON
/// </summary>
/// <param name="json">JSON string to parse</param>
/// <returns>IJsonValue representation of the JSON</returns>
public static IJsonValue Parse(string json)
{
if (string.IsNullOrEmpty(json))
{
if (Log.IsErrorEnabled)
Log.Error("Attempt to parse null or empty JSON string");
throw new JsonException("Attempt to parse null or empty JSON string");
}
using (var lex = new JsonLexicalAnalyzer(json))
{
return ShiftReduceParse(json, lex);
}
}
