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Private Function _BlockEnd0(ByVal s As ReadOnlySpan(Of Char), ByVal cp As Integer, ByVal len As Integer, ByVal position As Integer, ByVal line As Integer, ByVal column As Integer) As FAMatch

Quote:

And yet otherwise in my tests, the spanless string approach i use (Substring instead of Splice) doesn't yield noticeably less performance. That leads me to suspect I'm not using it to its fullest - an encouraging thought in the big picture because it means I can get even more speed out of it. I'm not sure that's possible though because no matter how I think about approaching it a copy is always necessary by the time you hit the Value property off FAMatch. It's a head scratcher.

Microsoft Regex "Lexer": [■■■■■■■■■■] 100% Found 220000 matches in 35ms
Microsoft Regex compiled "Lexer": [■■■■■■■■■■] 100% Found 220000 matches in 20ms
FAStringRunner (proto): [■■■■■■■■■■] 100% Found 220000 matches in 7ms
FATextReaderRunner: (proto) [■■■■■■■■■■] 100% Found 220000 matches in 13ms
FAStringDfaTableRunner: [■■■■■■■■■■] 100% Found 220000 matches in 10ms
FATextReaderDfaTableRunner: [■■■■■■■■■■] 100% Found 220000 matches in 14ms
FAStringStateRunner (NFA): [■■■■■■■■■■] 100% Found 220000 matches in 145ms
FAStringStateRunner (Compact NFA): [■■■■■■■■■■] 100% Found 220000 matches in 43ms
FATextReaderStateRunner (Compact NFA): [■■■■■■■■■■] 100% Found 220000 matches in 48ms
FAStringStateRunner (DFA): [■■■■■■■■■■] 100% Found 220000 matches in 11ms
FATextReaderStateRunner (DFA): [■■■■■■■■■■] 100% Found 220000 matches in 16ms
FAStringRunner (Compiled): [■■■■■■■■■■] 100% Found 220000 matches in 7ms
FATextReaderRunner (Compiled): [■■■■■■■■■■] 100% Found 220000 matches in 12ms

Quote:

If I can't get another 10% out of this I don't think it's worth the trouble.

// Matches C line comments or block comments
private FAMatch _BlockEnd0(ReadOnlySpan<char> s, int cp, int len, int position, int line, int column) {
q0:
    // [\*]
    if ((cp == 42)) {
        this.Advance(s, ref cp, ref len, false);
        goto q1;
    }
    goto errorout;
q1:
    // [\/]
    if ((cp == 47)) {
        this.Advance(s, ref cp, ref len, false);
        goto q2;
    }
    goto errorout;
q2:
    return FAMatch.Create(0, s.Slice(position, len).ToString(), position, line, column);
errorout:
    if ((cp == -1)) {
        return FAMatch.Create(-1, s.Slice(position, len).ToString(), position, line, column);
    }
    this.Advance(s, ref cp, ref len, false);
    goto q0;
}
private FAMatch NextMatchImpl(ReadOnlySpan<char> s) {
    int ch;
    int len;
    int p;
    int l;
    int c;
    ch = -1;
    len = 0;
    if ((this.position == -1)) {
        this.position = 0;
    }
    p = this.position;
    l = this.line;
    c = this.column;
    this.Advance(s, ref ch, ref len, true);
    // q0:
    // [\/]
    if ((ch == 47)) {
        this.Advance(s, ref ch, ref len, false);
        goto q1;
    }
    goto errorout;
q1:
    // [\*]
    if ((ch == 42)) {
        this.Advance(s, ref ch, ref len, false);
        goto q2;
    }
    goto errorout;
q2:
    return _BlockEnd0(s, ch, len, p, l, c);
errorout:
    if (((ch == -1) 
                || (ch == 47))) {
        if ((len == 0)) {
            return FAMatch.Create(-2, null, 0, 0, 0);
        }
        return FAMatch.Create(-1, s.Slice(p, len).ToString(), p, l, c);
    }
    this.Advance(s, ref ch, ref len, false);
    goto errorout;
}

Quote:

I actually did dotNetPeek them