crc.c

/**
 * \file
 * Functions and types for CRC checks.
 *
 * Generated on Thu Sep 27 11:30:10 2018
 * by pycrc v0.9.1, https://pycrc.org
 * using the configuration:
 *  - Width         = 8
 *  - Poly          = 0x07
 *  - XorIn         = 0x00
 *  - ReflectIn     = False
 *  - XorOut        = 0x00
 *  - ReflectOut    = False
 *  - Algorithm     = bit-by-bit-fast
 */
#include "crc.h" /* include the header file generated with pycrc */
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

crc_t crc_update(crc_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 = *d++;
        for (i = 0x80; i > 0; i >>= 1) {
            bit = crc & 0x80;
            if (c & i) {
                bit = !bit;
            }
            crc <<= 1;
            if (bit) {
                crc ^= 0x07;
            }
        }
        crc &= 0xff;
    }
    return crc & 0xff;
}