Method begin

src/butil/strings/string_piece.h:274–274

  char back_or_0() const { return length_ ? *(ptr_ + length_ - 1) : '\0'; }

  const_iterator begin() const { return ptr_; }
  const_iterator end() const { return ptr_ + length_; }
  const_reverse_iterator rbegin() const {
    return const_reverse_iterator(ptr_ + length_);