public RegexFindOptimizations(RegexNode root, RegexOptions options, CultureInfo culture)
{
_rightToLeft = (options & RegexOptions.RightToLeft) != 0;
_textInfo = culture.TextInfo;
MinRequiredLength = root.ComputeMinLength();
// Compute any anchor starting the expression. If there is one, we won't need to search for anything,
// as we can just match at that single location.
LeadingAnchor = RegexPrefixAnalyzer.FindLeadingAnchor(root);
if (_rightToLeft && LeadingAnchor == RegexNodeKind.Bol)
{
// Filter out Bol for RightToLeft, as we don't currently optimize for it.
LeadingAnchor = RegexNodeKind.Unknown;
}
if (LeadingAnchor is RegexNodeKind.Beginning or RegexNodeKind.Start or RegexNodeKind.EndZ or RegexNodeKind.End)
{
FindMode = (LeadingAnchor, _rightToLeft) switch
{
(RegexNodeKind.Beginning, false) => FindNextStartingPositionMode.LeadingAnchor_LeftToRight_Beginning,
(RegexNodeKind.Beginning, true) => FindNextStartingPositionMode.LeadingAnchor_RightToLeft_Beginning,
(RegexNodeKind.Start, false) => FindNextStartingPositionMode.LeadingAnchor_LeftToRight_Start,
(RegexNodeKind.Start, true) => FindNextStartingPositionMode.LeadingAnchor_RightToLeft_Start,
(RegexNodeKind.End, false) => FindNextStartingPositionMode.LeadingAnchor_LeftToRight_End,
(RegexNodeKind.End, true) => FindNextStartingPositionMode.LeadingAnchor_RightToLeft_End,
(_, false) => FindNextStartingPositionMode.LeadingAnchor_LeftToRight_EndZ,
(_, true) => FindNextStartingPositionMode.LeadingAnchor_RightToLeft_EndZ,
};
return;
}