/** @ingroup emulation
 * @brief Emulate a target
 * @return Returns 0 on success, otherwise returns libnfc's error code (negative value).
 *
 * @param pnd \a nfc_device struct pointer that represents currently used device
 * @param emulator \nfc_emulator struct point that handles input/output functions
 *
 * If timeout equals to 0, the function blocks indefinitely (until an error is raised or function is completed)
 * If timeout equals to -1, the default timeout will be used
 */
int
nfc_emulate_target(nfc_device *pnd, struct nfc_emulator *emulator, const int timeout)
{
  uint8_t abtRx[ISO7816_SHORT_R_APDU_MAX_LEN];
  uint8_t abtTx[ISO7816_SHORT_C_APDU_MAX_LEN];

  int res;
  if ((res = nfc_target_init(pnd, emulator->target, abtRx, sizeof(abtRx), timeout)) < 0) {
    return res;
  }

  size_t szRx = res;
  int io_res = res;
  while (io_res >= 0) {
    io_res = emulator->state_machine->io(emulator, abtRx, szRx, abtTx, sizeof(abtTx));
    if (io_res > 0) {
      if ((res = nfc_target_send_bytes(pnd, abtTx, io_res, timeout)) < 0) {
        return res;
      }
    }
    if (io_res >= 0) {
      if ((res = nfc_target_receive_bytes(pnd, abtRx, sizeof(abtRx), timeout)) < 0) {
        return res;
      }
      szRx = res;
    }
  }
  return io_res;
}
bool receive_bytes (void)
{
    if (!nfc_target_receive_bytes(pnd,abtRx,&szRx)) {
        nfc_perror (pnd, "nfc_target_receive_bytes");
        exit(EXIT_FAILURE);
    }

    // Show received answer
    if (!quiet_output) {
        printf ("Received data: ");
        print_hex (abtRx, szRx);
    }
    // Succesful transfer
    return true;
}