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// SPDX-License-Identifier: LGPL-2.1-or-later
/*
*
* BlueZ - Bluetooth protocol stack for Linux
*
* Copyright (C) 2011-2014 Intel Corporation
* Copyright (C) 2002-2010 Marcel Holtmann <marcel@holtmann.org>
*
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "crc.h"
uint32_t crc24_bit_reverse(uint32_t value)
{
uint32_t result = 0;
uint8_t i;
for (i = 0; i < 24; i++)
result |= ((value >> i) & 1) << (23 - i);
return result;
}
uint32_t crc24_calculate(uint32_t preset, const uint8_t *data, uint8_t len)
{
uint32_t state = preset;
uint8_t i;
for (i = 0; i < len; i++) {
uint8_t n, cur = data[i];
for (n = 0; n < 8; n++) {
int next_bit = (state ^ cur) & 1;
cur >>= 1;
state >>= 1;
if (next_bit) {
state |= 1 << 23;
state ^= 0x5a6000;
}
}
}
return state;
}
uint32_t crc24_reverse(uint32_t crc, const uint8_t *data, uint8_t len)
{
uint32_t state = crc;
uint8_t i;
for (i = 0; i < len; i++) {
uint8_t n, cur = data[len - i - 1];
for (n = 0; n < 8; n++) {
int top_bit = state >> 23;
state = (state << 1) & 0xffffff;
state |= top_bit ^ ((cur >> (7 - n)) & 1);
if (top_bit)
state ^= 0xb4c000;
}
}
return state;
}
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