text: /**
   * Marlin 3D Printer Firmware
   *
   * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
   * Copyright (c) 2016 Bob Cousins bobcousins42@googlemail.com
   * Copyright (c) 2015-2016 Nico Tonnhofer wurstnase.reprap@gmail.com
   * Copyright (c) 2016 Victor Perez victor_pv@hotmail.com
   *
   * This program is free software: you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation, either version 3 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <https://www.gnu.org/licenses/>.
   *
   */
  #pragma once
  
  #include <stddef.h>
  #include <stdint.h>
  
  #include "../../libs/crc16.h"
  
  class PersistentStore {
  public:
  
    // Total available persistent storage space (in bytes)
    static size_t capacity();
  
    // Prepare to read or write
    static bool access_start();
  
    // Housecleaning after read or write
    static bool access_finish();
  
    // Write one or more bytes of data and update the CRC
    // Return 'true' on write error
    static bool write_data(int &pos, const uint8_t *value, size_t size, uint16_t *crc);
  
    // Read one or more bytes of data and update the CRC
    // Return 'true' on read error
    static bool read_data(int &pos, uint8_t *value, size_t size, uint16_t *crc, const bool writing=true);
  
    // Write one or more bytes of data
    // Return 'true' on write error
    static bool write_data(const int pos, const uint8_t *value, const size_t size=sizeof(uint8_t)) {
      int data_pos = pos;
      uint16_t crc = 0;
      return write_data(data_pos, value, size, &crc);
    }
  
    // Write a single byte of data
    // Return 'true' on write error
    static bool write_data(const int pos, const uint8_t value) { return write_data(pos, &value); }
  
    // Read one or more bytes of data
    // Return 'true' on read error
    static bool read_data(const int pos, uint8_t *value, const size_t size=1) {
      int data_pos = pos;
      uint16_t crc = 0;
      return read_data(data_pos, value, size, &crc);
    }
  };
  
  extern PersistentStore persistentStore;
  