Reflector error or optimisation?
- by David_001
Long story short: I used reflector on the System.Security.Util.Tokenizer class, and there's loads of goto statements in there.
Here's a brief example snippet:
Label_0026:
if (this._inSavedCharacter != -1)
{
num = this._inSavedCharacter;
this._inSavedCharacter = -1;
}
else
{
switch (this._inTokenSource)
{
case TokenSource.UnicodeByteArray:
if ((this._inIndex + 1) < this._inSize)
{
break;
}
stream.AddToken(-1);
return;
case TokenSource.UTF8ByteArray:
if (this._inIndex < this._inSize)
{
goto Label_00CF;
}
stream.AddToken(-1);
return;
case TokenSource.ASCIIByteArray:
if (this._inIndex < this._inSize)
{
goto Label_023C;
}
stream.AddToken(-1);
return;
case TokenSource.CharArray:
if (this._inIndex < this._inSize)
{
goto Label_0272;
}
stream.AddToken(-1);
return;
case TokenSource.String:
if (this._inIndex < this._inSize)
{
goto Label_02A8;
}
stream.AddToken(-1);
return;
case TokenSource.NestedStrings:
if (this._inNestedSize == 0)
{
goto Label_030D;
}
if (this._inNestedIndex >= this._inNestedSize)
{
goto Label_0306;
}
num = this._inNestedString[this._inNestedIndex++];
goto Label_0402;
default:
num = this._inTokenReader.Read();
if (num == -1)
{
stream.AddToken(-1);
return;
}
goto Label_0402;
}
num = (this._inBytes[this._inIndex + 1] << 8) + this._inBytes[this._inIndex];
this._inIndex += 2;
}
goto Label_0402;
Label_00CF:
num = this._inBytes[this._inIndex++];
if ((num & 0x80) != 0)
{
switch (((num & 240) >> 4))
{
case 8:
case 9:
case 10:
case 11:
throw new XmlSyntaxException(this.LineNo);
case 12:
case 13:
num &= 0x1f;
num3 = 2;
break;
case 14:
num &= 15;
num3 = 3;
break;
case 15:
throw new XmlSyntaxException(this.LineNo);
}
if (this._inIndex >= this._inSize)
{
throw new XmlSyntaxException(this.LineNo, Environment.GetResourceString("XMLSyntax_UnexpectedEndOfFile"));
}
byte num2 = this._inBytes[this._inIndex++];
if ((num2 & 0xc0) != 0x80)
{
throw new XmlSyntaxException(this.LineNo);
}
num = (num << 6) | (num2 & 0x3f);
if (num3 != 2)
{
if (this._inIndex >= this._inSize)
{
throw new XmlSyntaxException(this.LineNo, Environment.GetResourceString("XMLSyntax_UnexpectedEndOfFile"));
}
num2 = this._inBytes[this._inIndex++];
if ((num2 & 0xc0) != 0x80)
{
throw new XmlSyntaxException(this.LineNo);
}
num = (num << 6) | (num2 & 0x3f);
}
}
goto Label_0402;
Label_023C:
num = this._inBytes[this._inIndex++];
goto Label_0402;
Label_0272:
num = this._inChars[this._inIndex++];
goto Label_0402;
Label_02A8:
num = this._inString[this._inIndex++];
goto Label_0402;
Label_0306:
this._inNestedSize = 0;
I essentially wanted to know how the class worked, but the number of goto's makes it impossible. Arguably something like a Tokenizer class needs to be heavily optimised, so my question is: is Reflector getting it wrong, or is goto an optimisation for this class?
