blob: 68bfff22b525ef4c2e655922938e40b9d1eaf441 [file] [log] [blame]
/*
* Copyright (c) 2021 Workaround GmbH.
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <sys/crc.h>
/* crc table generated from polynomial 0x1EDC6F41UL (Castagnoli) */
static const uint32_t crc32c_table[16] = {
0x00000000UL, 0x105EC76FUL, 0x20BD8EDEUL, 0x30E349B1UL,
0x417B1DBCUL, 0x5125DAD3UL, 0x61C69362UL, 0x7198540DUL,
0x82F63B78UL, 0x92A8FC17UL, 0xA24BB5A6UL, 0xB21572C9UL,
0xC38D26C4UL, 0xD3D3E1ABUL, 0xE330A81AUL, 0xF36E6F75UL
};
/* This value needs to be XORed with the final crc value once crc for
* the entire stream is calculated. This is a requirement of crc32c algo.
*/
#define CRC32C_XOR_OUT 0xFFFFFFFFUL
/* The crc32c algorithm requires the below value as Init value at the
* beginning of the stream.
*/
#define CRC32C_INIT 0xFFFFFFFFUL
uint32_t crc32_c(uint32_t crc, const uint8_t *data,
size_t len, bool first_pkt, bool last_pkt)
{
if (first_pkt) {
crc = CRC32C_INIT;
}
for (size_t i = 0; i < len; i++) {
crc = crc32c_table[(crc ^ data[i]) & 0x0F] ^ (crc >> 4);
crc = crc32c_table[(crc ^ ((uint32_t)data[i] >> 4)) & 0x0F] ^ (crc >> 4);
}
return last_pkt ? (crc ^ CRC32C_XOR_OUT) : crc;
}