Method ToString

Bcore/src/main/cpp/base/stringpiece.h:120–122

We also define ToString() here, since many other string-like interfaces name the routine that converts to a C++ string "ToString", and it's confusing to have the method that does that for a StringPiece be called "as_string()". We also leave the "as_string()" method defined here for existing code.

  // for a StringPiece be called "as_string()".  We also leave the
  // "as_string()" method defined here for existing code.
  std::string ToString() const {
    return std::string(data(), size());
  }

  void CopyToString(std::string* target) const {
    target->assign(ptr_, length_);