Function FindNth

be/src/gutil/strings/util.cc:1027–1037

------------------------------------------------------------------------ FindNth() return index of nth occurrence of c in the string, or string::npos if n > number of occurrences of c. (returns string::npos = -1 if n <= 0) ------------------------------------------------------------------------

//  (returns string::npos = -1 if n <= 0)
//------------------------------------------------------------------------
int FindNth(StringPiece s, char c, int n) {
  size_t pos = string::npos;

  for ( int i = 0; i < n; ++i ) {
    pos = s.find_first_of(c, pos + 1);
    if ( pos == StringPiece::npos ) {
      break;
    }
  }
  return pos;
}

//------------------------------------------------------------------------
// ReverseFindNth()