#include <string>
#include <algorithm>

class BufferedReader {
 public:
  explicit BufferedReader(PackageStream* stream): stream_(stream) {}
  int32_t Read(char* output_buffer, int32_t buffer_len) {
    int len = stream_->PackageLen();
    char* chararray = new char[len];
    while (this->data_.length() < (size_t) buffer_len) {
      int temp = stream_->ReadPackage(chararray);
      for (int i = 0; i < temp; i++) {
        this->data_ += chararray[i];
      }
      if (temp < len) {
        break;
      }
    }
    int res_len = std::min<int>(buffer_len, this->data_.length());
    for (int i = 0; i < res_len; ++i) {
      output_buffer[i] = this->data_[i];
    }
    delete[] chararray;
    this->data_.erase(this->data_.begin(), this->data_.begin() + res_len);
    return res_len;
  }

 private:
  PackageStream* stream_;
  string data_;
};