internal bool AddFC(RegexFC fc, bool concatenate)
{
if (!_cc.CanMerge || !fc._cc.CanMerge)
{
return(false);
}
if (concatenate)
{
if (!_nullable)
{
return(true);
}
if (!fc._nullable)
{
_nullable = false;
}
}
else
{
if (fc._nullable)
{
_nullable = true;
}
}
_caseInsensitive |= fc._caseInsensitive;
_cc.AddCharClass(fc._cc);
return(true);
}
/*
* We also use a stack of RegexFC objects.
* This is the push.
*/
private void PushFC(RegexFC fc)
{
if (_fcDepth >= _fcStack.Length)
{
RegexFC[] expanded = new RegexFC[_fcDepth * 2];
Array.Copy(_fcStack, 0, expanded, 0, _fcDepth);
_fcStack = expanded;
}
_fcStack[_fcDepth++] = fc;
}
/// <summary>
/// This is the one of the only two functions that should be called from outside.
/// It takes a RegexTree and computes the set of chars that can start it.
/// </summary>
public static RegexPrefix FirstChars(RegexTree t)
{
// Create/rent buffers
Span <int> intSpan = stackalloc int[StackBufferSize];
RegexFCD s = new RegexFCD(intSpan);
RegexFC fc = s.RegexFCFromRegexTree(t);
s.Dispose();
if (fc == null || fc._nullable)
{
return(default);
/*
* This is the one of the only two functions that should be called from outside.
* It takes a RegexTree and computes the set of chars that can start it.
*/
internal static RegexPrefix FirstChars(RegexTree t)
{
RegexFCD s = new RegexFCD();
RegexFC fc = s.RegexFCFromRegexTree(t);
if (fc == null || fc._nullable)
{
return(null);
}
CultureInfo culture = ((t._options & RegexOptions.CultureInvariant) != 0) ? CultureInfo.InvariantCulture : CultureInfo.CurrentCulture;
return(new RegexPrefix(fc.GetFirstChars(culture), fc.IsCaseInsensitive()));
}
/*
* FC computation and shortcut cases for each node type
*/
private void CalculateFC(int NodeType, RegexNode node, int CurIndex)
{
bool ci = false;
bool rtl = false;
if (NodeType <= RegexNode.Ref)
{
if ((node._options & RegexOptions.IgnoreCase) != 0)
{
ci = true;
}
if ((node._options & RegexOptions.RightToLeft) != 0)
{
rtl = true;
}
}
switch (NodeType)
{
case RegexNode.Concatenate | BeforeChild:
case RegexNode.Alternate | BeforeChild:
case RegexNode.Testref | BeforeChild:
case RegexNode.Loop | BeforeChild:
case RegexNode.Lazyloop | BeforeChild:
break;
case RegexNode.Testgroup | BeforeChild:
if (CurIndex == 0)
{
SkipChild();
}
break;
case RegexNode.Empty:
PushFC(new RegexFC(true));
break;
case RegexNode.Concatenate | AfterChild:
if (CurIndex != 0)
{
RegexFC child = PopFC();
RegexFC cumul = TopFC();
_failed = !cumul.AddFC(child, true);
}
if (!TopFC()._nullable)
{
_skipAllChildren = true;
}
break;
case RegexNode.Testgroup | AfterChild:
if (CurIndex > 1)
{
RegexFC child = PopFC();
RegexFC cumul = TopFC();
_failed = !cumul.AddFC(child, false);
}
break;
case RegexNode.Alternate | AfterChild:
case RegexNode.Testref | AfterChild:
if (CurIndex != 0)
{
RegexFC child = PopFC();
RegexFC cumul = TopFC();
_failed = !cumul.AddFC(child, false);
}
break;
case RegexNode.Loop | AfterChild:
case RegexNode.Lazyloop | AfterChild:
if (node._m == 0)
{
TopFC()._nullable = true;
}
break;
case RegexNode.Group | BeforeChild:
case RegexNode.Group | AfterChild:
case RegexNode.Capture | BeforeChild:
case RegexNode.Capture | AfterChild:
case RegexNode.Greedy | BeforeChild:
case RegexNode.Greedy | AfterChild:
break;
case RegexNode.Require | BeforeChild:
case RegexNode.Prevent | BeforeChild:
SkipChild();
PushFC(new RegexFC(true));
break;
case RegexNode.Require | AfterChild:
case RegexNode.Prevent | AfterChild:
break;
case RegexNode.One:
case RegexNode.Notone:
PushFC(new RegexFC(node._ch, NodeType == RegexNode.Notone, false, ci));
break;
case RegexNode.Oneloop:
case RegexNode.Onelazy:
PushFC(new RegexFC(node._ch, false, node._m == 0, ci));
break;
case RegexNode.Notoneloop:
case RegexNode.Notonelazy:
PushFC(new RegexFC(node._ch, true, node._m == 0, ci));
break;
case RegexNode.Multi:
if (node._str.Length == 0)
{
PushFC(new RegexFC(true));
}
else if (!rtl)
{
PushFC(new RegexFC(node._str[0], false, false, ci));
}
else
{
PushFC(new RegexFC(node._str[node._str.Length - 1], false, false, ci));
}
break;
case RegexNode.Set:
PushFC(new RegexFC(node._str, false, ci));
break;
case RegexNode.Setloop:
case RegexNode.Setlazy:
PushFC(new RegexFC(node._str, node._m == 0, ci));
break;
case RegexNode.Ref:
case RegexNode.CallSubroutine:
PushFC(new RegexFC(RegexCharClass.AnyClass, true, false));
break;
case RegexNode.Nothing:
case RegexNode.Bol:
case RegexNode.Eol:
case RegexNode.Boundary:
case RegexNode.Nonboundary:
case RegexNode.ECMABoundary:
case RegexNode.NonECMABoundary:
case RegexNode.Beginning:
case RegexNode.Start:
case RegexNode.EndZ:
case RegexNode.End:
case RegexNode.ResetMatchStart:
PushFC(new RegexFC(true));
break;
default:
throw new ArgumentException(SR.Format(SR.UnexpectedOpcode, NodeType.ToString(CultureInfo.CurrentCulture)));
}
}