Function TrimStringT

src/butil/strings/string_util.cc:161–190

template<typename STR>
TrimPositions TrimStringT(const STR& input,
                          const STR& trim_chars,
                          TrimPositions positions,
                          STR* output) {
  // Find the edges of leading/trailing whitespace as desired.
  const size_t last_char = input.length() - 1;
  const size_t first_good_char = (positions & TRIM_LEADING) ?
      input.find_first_not_of(trim_chars) : 0;
  const size_t last_good_char = (positions & TRIM_TRAILING) ?
      input.find_last_not_of(trim_chars) : last_char;

  // When the string was all whitespace, report that we stripped off whitespace
  // from whichever position the caller was interested in.  For empty input, we
  // stripped no whitespace, but we still need to clear |output|.
  if (input.empty() ||
      (first_good_char == STR::npos) || (last_good_char == STR::npos)) {
    bool input_was_empty = input.empty();  // in case output == &input
    output->clear();
    return input_was_empty ? TRIM_NONE : positions;
  }

  // Trim the whitespace.
  *output =
      input.substr(first_good_char, last_good_char - first_good_char + 1);

  // Return where we trimmed from.
  return static_cast<TrimPositions>(
      ((first_good_char == 0) ? TRIM_NONE : TRIM_LEADING) |
      ((last_good_char == last_char) ? TRIM_NONE : TRIM_TRAILING));
}

bool TrimString(const string16& input,
                const butil::StringPiece16& trim_chars,