System.Text.RegularExpressions.Match.MatchIndex C# (CSharp) Method

        internal virtual int MatchIndex(int cap)
        {
            int i = _matches[cap][_matchcount[cap] * 2 - 2];
            if (i >= 0)
                return i;

            return _matches[cap][-3 - i];
        }

 /*
  * Call out to runmatch to get around visibility issues
  */
 protected int MatchIndex(int cap)
 {
     return(_runmatch.MatchIndex(cap));
 }