Endianess.ino

/****************************************************************************************************************************
  Endianess.ino - Network byte order conversion functions - part of the Firmware Updater for the
  Arduino Nano-33 IoT, MKR WiFi 1010, Arduino MKR Vidor 4000, and Arduino UNO WiFi Rev.2., Adafruit's nRF52 boards

  Based on and modified from WiFiNINA library https://www.arduino.cc/en/Reference/WiFiNINA
  to support nRF52, SAMD21/SAMD51, STM32F/L/H/G/WB/MP1, Teensy, etc. boards besides Nano-33 IoT, MKRWIFI1010, MKRVIDOR400, etc.

  Built by Khoi Hoang https://github.com/khoih-prog/WiFiNINA_Generic
  Licensed under MIT license

  Copyright (c) 2018 Arduino SA. All rights reserved.
  Copyright (c) 2011-2014 Arduino LLC.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *****************************************************************************************************************************/

bool isBigEndian()
{
  uint32_t test = 0x11223344;
  uint8_t *pTest = reinterpret_cast<uint8_t *>(&test);
  return pTest[0] == 0x11;
}

uint32_t fromNetwork32(uint32_t from)
{
  static const bool be = isBigEndian();

  if (be)
  {
    return from;
  }
  else
  {
    uint8_t *pFrom = reinterpret_cast<uint8_t *>(&from);
    uint32_t to;

    to = pFrom[0];
    to <<= 8;
    to |= pFrom[1];
    to <<= 8;
    to |= pFrom[2];
    to <<= 8;
    to |= pFrom[3];
    return to;
  }
}

uint16_t fromNetwork16(uint16_t from)
{
  static bool be = isBigEndian();

  if (be)
  {
    return from;
  }
  else
  {
    uint8_t *pFrom = reinterpret_cast<uint8_t *>(&from);
    uint16_t to;

    to = pFrom[0];
    to <<= 8;
    to |= pFrom[1];
    return to;
  }
}

uint32_t toNetwork32(uint32_t to)
{
  return fromNetwork32(to);
}

uint16_t toNetwork16(uint16_t to)
{
  return fromNetwork16(to);
}