private static object ParseExpression(JsonToken token, TokenStream ts)
{
if (token == null)
{
token = ts.GetNextToken();
}
switch (token.Type)
{
case JsonToken.TokenType.String:
logger.Debug("Found String " + token.Value);
return token.Value;
case JsonToken.TokenType.Number:
logger.Debug("Found Number " + token.Number);
return token.Number;
case JsonToken.TokenType.False:
logger.Debug("Found False");
return false;
case JsonToken.TokenType.True:
logger.Debug("Found True");
return true;
case JsonToken.TokenType.Null:
logger.Debug("Found Null");
return null;
case JsonToken.TokenType.ObjectStart:
logger.Debug("Found ObjectStart");
return ParseObject(ts);
case JsonToken.TokenType.ArrayStart:
logger.Debug("Found ArrayStart");
return ParseArray(ts);
case JsonToken.TokenType.Undefined:
default:
throw new ArgumentException("parse error");
}
}
public void JsonTokenConstructorTest()
{
JsonToken target = new JsonToken();
Assert.IsNotNull(target);
}
/// <summary>
/// From the current position, extract the next token
/// </summary>
/// <returns>The next token, or null if the stream is at the EOF</returns>
public JsonToken GetNextToken()
{
var token = new JsonToken();
try
{
// Read char (and first skip over all whitespaces)
// We use .Read() instead of .Peek() here, as Read() is blocking.
// .Peek() would suggest an EOF even if there is none when used in combination a WebRequest
char cur;
do
{
int read = reader.Read();
// Check for EOF
if (read == -1)
{
return null;
}
cur = (char) read;
} while (Char.IsWhiteSpace(cur));
// Check for Json tokens
switch (cur)
{
case '{':
token.Type = JsonToken.TokenType.ObjectStart;
break;
case '}':
token.Type = JsonToken.TokenType.ObjectEnd;
break;
case '[':
token.Type = JsonToken.TokenType.ArrayStart;
break;
case ']':
token.Type = JsonToken.TokenType.ArrayEnd;
break;
case ':':
token.Type = JsonToken.TokenType.NameSeperator;
break;
case ',':
token.Type = JsonToken.TokenType.MemberSeperator;
break;
case '"':
case '\'':
ParseString(token, cur);
break;
case 'f':
GetFalseToken(token);
break;
case 't':
// this might be the true token
GetTrueToken(token);
break;
case 'n':
// this might be nul
GetNullToken(token);
break;
default:
token.Type = JsonToken.TokenType.Undefined;
if (Char.IsNumber(cur) || cur == '-')
{
var sb = new StringBuilder(BuilderBufferSize);
sb.Append(cur);
while (IsTokenSeperator((char) reader.Peek()) == false || ((char) reader.Peek() == '.') ||
((char) reader.Peek() == '+') || ((char) reader.Peek() == '-'))
{
sb.Append((char) reader.Read());
}
token.Value = sb.ToString();
decimal decNumber;
if (Decimal.TryParse(
token.Value, NumberStyles.Number | NumberStyles.AllowExponent,
CultureInfo.InvariantCulture, out decNumber))
{
token.Number = decNumber;
token.Type = JsonToken.TokenType.Number;
}
}
break;
}
}
catch (IOException ex)
{
throw new IOException("Unable to retrieve the next token", ex);
}
return token;
}
/// <summary>
/// Parses a Json String as per http://www.json.org/ acknowledging escaped chars
/// </summary>
private void ParseString(JsonToken token, char cur)
{
char seperator = cur;
token.Type = JsonToken.TokenType.String;
// let's read in the string
var sb = new StringBuilder(BuilderBufferSize);
char next;
while ((next = (char) reader.Read()) != seperator)
{
if (next == '\\')
{
next = (char) reader.Read();
switch (next)
{
case 'n':
next = '\n';
break;
case 'r':
next = '\r';
break;
case 't':
next = '\t';
break;
case '\'':
next = '\'';
break;
case '/':
next = '/';
break;
case '"':
next = '\"';
break;
case '\\':
next = '\\';
break;
case 'b':
// backspace
next = '\b';
break;
case 'u':
// 4 digit hexadecimal unicode escape
char[] escapedCharAry = new char[4];
for (int i = 0; i < 4; i++)
{
escapedCharAry[i] = (char) reader.Read();
}
String escapedCharStr = new String(escapedCharAry);
int escapedCharInt = int.Parse(
escapedCharStr, NumberStyles.HexNumber, NumberFormatInfo.InvariantInfo);
next = Convert.ToChar(escapedCharInt);
break;
default:
break;
}
}
sb.Append(next);
}
token.Value = sb.ToString();
}
// starts at the a of the false
private void GetTrueToken(JsonToken token)
{
token.Type = JsonToken.TokenType.Undefined;
// this might be the false token
if (LookupToken("rue"))
{
token.Type = JsonToken.TokenType.True;
}
return;
}
// starts at the a of the false
private void GetNullToken(JsonToken token)
{
token.Type = JsonToken.TokenType.Undefined;
// this might be the false token
if (LookupToken("ull"))
{
token.Type = JsonToken.TokenType.Null;
}
return;
}
/// <summary>
/// Parses a Json String as per http://www.json.org/ acknowledging escaped chars
/// </summary>
private void ParseString(JsonToken token, char cur)
{
char seperator = cur;
token.Type = JsonToken.TokenType.String;
// let's read in the string
var sb = new StringBuilder(BuilderBufferSize);
char next;
while ((next = (char)reader.Read()) != seperator)
{
if (next == '\\')
{
next = (char)reader.Read();
switch (next)
{
case 'n':
next = '\n';
break;
case 'r':
next = '\r';
break;
case 't':
next = '\t';
break;
case '\'':
next = '\'';
break;
case '/':
next = '/';
break;
case '"':
next = '\"';
break;
case '\\':
next = '\\';
break;
case 'b':
// backspace
next = '\b';
break;
case 'u':
// 4 digit hexadecimal unicode escape
char[] escapedCharAry = new char[4];
for (int i = 0; i < 4; i++)
{
escapedCharAry[i] = (char)reader.Read();
}
String escapedCharStr = new String(escapedCharAry);
int escapedCharInt = int.Parse(
escapedCharStr, NumberStyles.HexNumber, NumberFormatInfo.InvariantInfo);
next = Convert.ToChar(escapedCharInt);
break;
default:
break;
}
}
sb.Append(next);
}
token.Value = sb.ToString();
}
/// <summary>
/// From the current position, extract the next token
/// </summary>
/// <returns>The next token, or null if the stream is at the EOF</returns>
public JsonToken GetNextToken()
{
var token = new JsonToken();
try
{
// Read char (and first skip over all whitespaces)
// We use .Read() instead of .Peek() here, as Read() is blocking.
// .Peek() would suggest an EOF even if there is none when used in combination a WebRequest
char cur;
do
{
int read = reader.Read();
// Check for EOF
if (read == -1)
{
return(null);
}
cur = (char)read;
} while (Char.IsWhiteSpace(cur));
// Check for Json tokens
switch (cur)
{
case '{':
token.Type = JsonToken.TokenType.ObjectStart;
break;
case '}':
token.Type = JsonToken.TokenType.ObjectEnd;
break;
case '[':
token.Type = JsonToken.TokenType.ArrayStart;
break;
case ']':
token.Type = JsonToken.TokenType.ArrayEnd;
break;
case ':':
token.Type = JsonToken.TokenType.NameSeperator;
break;
case ',':
token.Type = JsonToken.TokenType.MemberSeperator;
break;
case '"':
case '\'':
ParseString(token, cur);
break;
case 'f':
GetFalseToken(token);
break;
case 't':
// this might be the true token
GetTrueToken(token);
break;
case 'n':
// this might be nul
GetNullToken(token);
break;
default:
token.Type = JsonToken.TokenType.Undefined;
if (Char.IsNumber(cur) || cur == '-')
{
var sb = new StringBuilder(BuilderBufferSize);
sb.Append(cur);
while (IsTokenSeperator((char)reader.Peek()) == false || ((char)reader.Peek() == '.') ||
((char)reader.Peek() == '+') || ((char)reader.Peek() == '-'))
{
sb.Append((char)reader.Read());
}
token.Value = sb.ToString();
decimal decNumber;
if (Decimal.TryParse(
token.Value, NumberStyles.Number | NumberStyles.AllowExponent,
CultureInfo.InvariantCulture, out decNumber))
{
token.Number = decNumber;
token.Type = JsonToken.TokenType.Number;
}
}
break;
}
}
catch (IOException ex)
{
throw new IOException("Unable to retrieve the next token", ex);
}
return(token);
}
