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// SPDX-License-Identifier: GPL-2.0-or-later
/***************************************************************************
* Copyright (C) 2013-2014 by Franck Jullien *
* elec4fun@gmail.com *
* *
* Copyright (C) 2022 Otto-von-Guericke-Universität Magdeburg *
* marian.buschsieweke@ovgu.de *
***************************************************************************/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "crc32.h"
#include <stdint.h>
#include <stddef.h>
static uint32_t crc_le_step(uint32_t poly, uint32_t crc, uint32_t data_in,
unsigned int data_bits)
{
for (unsigned int i = 0; i < data_bits; i++) {
uint32_t d, c;
d = ((data_in >> i) & 0x1) ? 0xffffffff : 0;
c = (crc & 0x1) ? 0xffffffff : 0;
crc = crc >> 1;
crc = crc ^ ((d ^ c) & poly);
}
return crc;
}
uint32_t crc32_le(uint32_t poly, uint32_t seed, const void *_data,
size_t data_len)
{
if (((uintptr_t)_data & 0x3) || (data_len & 0x3)) {
/* data is unaligned, processing data one byte at a time */
const uint8_t *data = _data;
for (size_t i = 0; i < data_len; i++)
seed = crc_le_step(poly, seed, data[i], 8);
} else {
/* data is aligned, processing 32 bit at a time */
data_len >>= 2;
const uint32_t *data = _data;
for (size_t i = 0; i < data_len; i++)
seed = crc_le_step(poly, seed, data[i], 32);
}
return seed;
}
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