// Copyright (C) 2026 Hector van der Aa <hector@h3cx.dev>
// Copyright (C) 2026 Association Exergie <association.exergie@gmail.com>
// SPDX-License-Identifier: MIT
#include "telemetry_common.h"
#include <stdlib.h>

uint16_t crc16_ccitt(const uint8_t *data, uint16_t length) {
  uint16_t crc = 0xFFFF;

  for (uint16_t i = 0; i < length; i++) {
    crc ^= (uint16_t)data[i] << 8;

    for (uint8_t j = 0; j < 8; j++) {
      if (crc & 0x8000)
        crc = (crc << 1) ^ 0x1021;
      else
        crc <<= 1;
    }
  }

  return crc;
}