Class MultiStringStream

cpp/src/arrow/json/chunker.cc:57–100

RapidJson custom stream for reading JSON stored in multiple buffers http://rapidjson.org/md_doc_stream.html#CustomStream

/// RapidJson custom stream for reading JSON stored in multiple buffers
/// http://rapidjson.org/md_doc_stream.html#CustomStream
class MultiStringStream {
 public:
  using Ch = char;
  explicit MultiStringStream(std::vector<string_view> strings)
      : strings_(std::move(strings)) {
    std::reverse(strings_.begin(), strings_.end());
  }
  explicit MultiStringStream(const BufferVector& buffers) : strings_(buffers.size()) {
    for (size_t i = 0; i < buffers.size(); ++i) {
      strings_[i] = string_view(*buffers[i]);
    }
    std::reverse(strings_.begin(), strings_.end());
  }
  char Peek() const {
    if (strings_.size() == 0) return '\0';
    return strings_.back()[0];
  }
  char Take() {
    if (strings_.size() == 0) return '\0';
    char taken = strings_.back()[0];
    if (strings_.back().size() == 1) {
      strings_.pop_back();
    } else {
      strings_.back() = strings_.back().substr(1);
    }
    ++index_;
    return taken;
  }
  size_t Tell() { return index_; }
  void Put(char) { ARROW_LOG(FATAL) << "not implemented"; }
  void Flush() { ARROW_LOG(FATAL) << "not implemented"; }
  char* PutBegin() {
    ARROW_LOG(FATAL) << "not implemented";
    return nullptr;
  }
  size_t PutEnd(char*) {
    ARROW_LOG(FATAL) << "not implemented";
    return 0;
  }

 private:
  size_t index_ = 0;
  std::vector<string_view> strings_;
};

template <typename Stream>
static size_t ConsumeWholeObject(Stream&& stream) {