1 /*
2 * Copyright (c) 2018 Workaround GmbH.
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/sys/crc.h>
8
crc32_ieee(const uint8_t * data,size_t len)9 uint32_t crc32_ieee(const uint8_t *data, size_t len)
10 {
11 return crc32_ieee_update(0x0, data, len);
12 }
13
crc32_ieee_update(uint32_t crc,const uint8_t * data,size_t len)14 uint32_t crc32_ieee_update(uint32_t crc, const uint8_t *data, size_t len)
15 {
16 /* crc table generated from polynomial 0xedb88320 */
17 static const uint32_t table[16] = {
18 0x00000000U, 0x1db71064U, 0x3b6e20c8U, 0x26d930acU,
19 0x76dc4190U, 0x6b6b51f4U, 0x4db26158U, 0x5005713cU,
20 0xedb88320U, 0xf00f9344U, 0xd6d6a3e8U, 0xcb61b38cU,
21 0x9b64c2b0U, 0x86d3d2d4U, 0xa00ae278U, 0xbdbdf21cU,
22 };
23
24 crc = ~crc;
25
26 for (size_t i = 0; i < len; i++) {
27 uint8_t byte = data[i];
28
29 crc = (crc >> 4) ^ table[(crc ^ byte) & 0x0f];
30 crc = (crc >> 4) ^ table[(crc ^ ((uint32_t)byte >> 4)) & 0x0f];
31 }
32
33 return (~crc);
34 }
35
