private bool ScanIdentifier_SlowPath(ref TokenInfo info)
{
int start = TextWindow.Position;
this.ResetIdentBuffer();
info.IsVerbatim = TextWindow.PeekChar() == '@' && TextWindow.PeekChar(1) == '"';
var isAnnoStart = !info.IsVerbatim && TextWindow.PeekChar() == '@';
if (info.IsVerbatim || isAnnoStart)
{
TextWindow.AdvanceChar();
}
while (true)
{
char surrogateCharacter = SlidingTextWindow.InvalidCharacter;
bool isEscaped = false;
char ch = TextWindow.PeekChar();
top:
switch (ch)
{
case '\\':
if (!isEscaped && TextWindow.IsUnicodeEscape())
{
// ^^^^^^^ otherwise \u005Cu1234 looks just like \u1234! (i.e. escape within escape)
info.HasIdentifierEscapeSequence = true;
isEscaped = true;
ch = TextWindow.PeekUnicodeEscape(out surrogateCharacter);
goto top;
}
goto default;
case '$':
goto LoopExit;
case SlidingTextWindow.InvalidCharacter:
if (!TextWindow.IsReallyAtEnd())
{
goto default;
}
goto LoopExit;
case '_':
case 'A':
case 'B':
case 'C':
case 'D':
case 'E':
case 'F':
case 'G':
case 'H':
case 'I':
case 'J':
case 'K':
case 'L':
case 'M':
case 'N':
case 'O':
case 'P':
case 'Q':
case 'R':
case 'S':
case 'T':
case 'U':
case 'V':
case 'W':
case 'X':
case 'Y':
case 'Z':
case 'a':
case 'b':
case 'c':
case 'd':
case 'e':
case 'f':
case 'g':
case 'h':
case 'i':
case 'j':
case 'k':
case 'l':
case 'm':
case 'n':
case 'o':
case 'p':
case 'q':
case 'r':
case 's':
case 't':
case 'u':
case 'v':
case 'w':
case 'x':
case 'y':
case 'z':
{
// Again, these are the 'common' identifier characters...
break;
}
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
{
if (this._identLen == 0)
{
goto LoopExit;
}
// Again, these are the 'common' identifier characters...
break;
}
case ' ':
case '\t':
case '.':
case ';':
case '(':
case ')':
case ',':
// ...and these are the 'common' stop characters.
goto LoopExit;
case '<':
if (this._identLen == 0 && this.ModeIs(LexerMode.DebuggerSyntax) && TextWindow.PeekChar(1) == '>')
{
// In DebuggerSyntax mode, identifiers are allowed to begin with <>.
TextWindow.AdvanceChar(2);
this.AddIdentChar('<');
this.AddIdentChar('>');
continue;
}
goto LoopExit;
default:
{
// This is the 'expensive' call
if (this._identLen == 0 && ch > 127 && SyntaxKindFacts.IsIdentifierStartCharacter(ch))
{
break;
}
else if (this._identLen > 0 && ch > 127 && SyntaxKindFacts.IsIdentifierPartCharacter(ch))
{
//// BUG 424819 : Handle identifier chars > 0xFFFF via surrogate pairs
if (SyntaxKindFacts.IsFormattingChar(ch))
{
if (isEscaped)
{
SyntaxDiagnosticInfo error;
TextWindow.NextCharOrUnicodeEscape(out surrogateCharacter, out error);
AddError(error);
}
else
{
TextWindow.AdvanceChar();
}
continue; // Ignore formatting characters
}
break;
}
else
{
// Not a valid identifier character, so bail.
goto LoopExit;
}
}
}
if (isEscaped)
{
SyntaxDiagnosticInfo error;
TextWindow.NextCharOrUnicodeEscape(out surrogateCharacter, out error);
AddError(error);
}
else
{
TextWindow.AdvanceChar();
}
this.AddIdentChar(ch);
if (surrogateCharacter != SlidingTextWindow.InvalidCharacter)
{
this.AddIdentChar(surrogateCharacter);
}
}
LoopExit:
var width = TextWindow.Width; // exact size of input characters
if (this._identLen > 0)
{
info.Text = TextWindow.GetInternedText();
// id buffer is identical to width in input
if (this._identLen == width)
{
info.StringValue = info.Text;
}
else
{
info.StringValue = TextWindow.Intern(this._identBuffer, 0, this._identLen);
}
return(true);
}
else
{
info.Text = null;
info.StringValue = null;
TextWindow.Reset(start);
return(false);
}
}
