crc_16_dnp_bbb.c

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/**
 * \file
 * Functions and types for CRC checks.
 *
 * Generated on Mon Aug 24 06:27:49 2020
 * by pycrc v0.9.2, https://pycrc.org
 * using the configuration:
 *  - Width         = 16
 *  - Poly          = 0x3d65
 *  - XorIn         = 0x0000
 *  - ReflectIn     = True
 *  - XorOut        = 0xffff
 *  - ReflectOut    = True
 *  - Algorithm     = bit-by-bit
 */
#include "crc_16_dnp_bbb.h" /* include the header file generated with pycrc */
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
 
static crc_16_dnp_bbb_t crc_16_dnp_bbb_reflect(crc_16_dnp_bbb_t data,
                                               size_t data_len);
 
crc_16_dnp_bbb_t crc_16_dnp_bbb_reflect(crc_16_dnp_bbb_t data,
                                        size_t data_len) {
  unsigned int i;
  crc_16_dnp_bbb_t ret;
 
  ret = data & 0x01;
  for (i = 1; i < data_len; i++) {
    data >>= 1;
    ret = (ret << 1) | (data & 0x01);
  }
  return ret;
}
 
crc_16_dnp_bbb_t crc_16_dnp_bbb_update(crc_16_dnp_bbb_t crc, const void *data,
                                       size_t data_len) {
  const unsigned char *d = (const unsigned char *)data;
  unsigned int i;
  bool bit;
  unsigned char c;
 
  while (data_len--) {
    c = crc_16_dnp_bbb_reflect(*d++, 8);
    for (i = 0; i < 8; i++) {
      bit = crc & 0x8000;
      crc = (crc << 1) | ((c >> (7 - i)) & 0x01);
      if (bit) {
        crc ^= 0x3d65;
      }
    }
    crc &= 0xffff;
  }
  return crc & 0xffff;
}
 
crc_16_dnp_bbb_t crc_16_dnp_bbb_finalize(crc_16_dnp_bbb_t crc) {
  unsigned int i;
  bool bit;
 
  for (i = 0; i < 16; i++) {
    bit = crc & 0x8000;
    crc <<= 1;
    if (bit) {
      crc ^= 0x3d65;
    }
  }
  crc = crc_16_dnp_bbb_reflect(crc, 16);
  return (crc ^ 0xffff) & 0xffff;
}