static public bool FindCurrentToken(SnapshotPoint currentPosition, out SnapshotSpan span)
{
ITextSnapshotLine textSnapshotLine = currentPosition.GetContainingLine();
LineBuffer lineText = new LineBuffer(textSnapshotLine);
int lineLength = textSnapshotLine.LengthIncludingLineBreak;
int iCol = (currentPosition - textSnapshotLine.Start);
// handle end of buffer case
if (iCol >= lineLength)
{
span = new SnapshotSpan(currentPosition.Snapshot, textSnapshotLine.End, 0);
return(true);
}
// scan left for base char
while ((iCol > 0) && !IsGraphemeBreak(lineText, iCol))
{
iCol--;
}
// if it's a word, return the word
char ch = lineText[iCol];
if (IsWordChar(ch))
{
return(FindCurrentWordCoords(new SnapshotPoint(currentPosition.Snapshot, textSnapshotLine.Start + iCol), out span));
}
// contiguous whitespace
int iBeg;
if (Char.IsWhiteSpace(ch))
{
for (iBeg = iCol - 1; iBeg >= 0; --iBeg)
{
if (!Char.IsWhiteSpace(lineText[iBeg]))
{
break;
}
}
iBeg++;
for (++iCol; iCol < lineLength; ++iCol)
{
if (!Char.IsWhiteSpace(lineText[iCol]))
{
break;
}
}
}
// contiguous punctuation and math symbols
else if (Char.IsPunctuation(ch) || IsMathSymbol(ch))
{
for (iBeg = iCol - 1; iBeg >= 0; --iBeg)
{
ch = lineText[iBeg];
if (!(Char.IsPunctuation(ch) || IsMathSymbol(ch)))
{
break;
}
}
iBeg++;
for (++iCol; iCol < lineLength; ++iCol)
{
ch = lineText[iCol];
if (!(Char.IsPunctuation(ch) || IsMathSymbol(ch)))
{
break;
}
}
}
//Let's get the whole surrogate pair.
else if (Char.IsHighSurrogate(ch) && ((iCol + 1) < lineLength) && Char.IsLowSurrogate(lineText[iCol + 1]))
{
iBeg = iCol;
iCol += 2;
}
// any other single char
else
{
iBeg = iCol++;
}
if (iCol > lineLength)
{
iCol = lineLength;
}
// Done -- fill in the data
span = new SnapshotSpan(currentPosition.Snapshot, (textSnapshotLine.Start + iBeg), (iCol - iBeg));
return(true);
}
// Returns true if iChar is at a grapheme boundary
public static bool IsGraphemeBreak(LineBuffer line, int iChar)
{
if (iChar <= 0)
{
return(true);
}
char cR = line[iChar];
if (cR == 0)
{
return(true);
}
char cL = line[(iChar - 1)];
if (cL == 0)
{
return(true);
}
// break around line breaks
if (IsLineBreak(cL) || IsLineBreak(cR))
{
return(true);
}
// don't separate a combining char from it's base
if (IsCombining(cR))
{
// A combining character after a quote or whitespace does not combine with the quote or whitespace
if (cL != '\'' && cL != '\"' && !Char.IsWhiteSpace(cL) && Char.IsLetter(cL))
{
return(false);
}
}
// don't break surrogate pairs
if (Char.IsHighSurrogate(cL))
{
return(!Char.IsLowSurrogate(cR));
}
HangulJamoType hjL = GetHangulJamoType(cL);
HangulJamoType hjR = GetHangulJamoType(cR);
if ((hjL != HangulJamoType.Other) && (hjR != HangulJamoType.Other))
{
switch (hjL)
{
case HangulJamoType.Lead:
return(false);
case HangulJamoType.Vowel:
return(HangulJamoType.Lead == hjR);
case HangulJamoType.Trail:
return(HangulJamoType.Trail != hjR);
default:
break;
}
}
return(true);
}
