class BufferedReader {
 public:
  explicit BufferedReader(PackageStream* stream) {
      str = stream;
      buffer = new char[str->PackageLen()];
      pos = 0;
      sizeBuf = 0;
  }
  int32_t Read(char* output_buffer, int32_t buffer_len) {
      int32_t sizeinit = buffer_len;
      while (buffer_len > 0) {
          if (pos == sizeBuf) {
              sizeBuf = str->ReadPackage(buffer);
              if (sizeBuf == 0) {
                  delete [] buffer;
                  return sizeinit - buffer_len;
              }
          }
          if (sizeBuf - pos < buffer_len) {
              memcpy(output_buffer, buffer + pos, sizeBuf - pos);
              pos = 0;
              buffer_len -= sizeBuf - pos;
              sizeBuf = str->ReadPackage(buffer);
              if (sizeBuf == 0) {
                  delete [] buffer;
                  return sizeinit - buffer_len;
              }
          } else {
              memcpy(output_buffer, buffer + pos, buffer_len);
              pos += buffer_len;
              buffer_len = 0;
          }
      }
      return sizeinit;
  }

 private:
  int32_t pos, sizeBuf;
  char* buffer;
  PackageStream* str;
};