mirror of
https://git.kernel.org/pub/scm/bluetooth/bluez.git
synced 2024-12-03 09:04:29 +08:00
85 lines
1.9 KiB
C
85 lines
1.9 KiB
C
/*
|
|
*
|
|
* BlueZ - Bluetooth protocol stack for Linux
|
|
*
|
|
* Copyright (C) 2011-2014 Intel Corporation
|
|
* Copyright (C) 2002-2010 Marcel Holtmann <marcel@holtmann.org>
|
|
*
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*
|
|
*/
|
|
|
|
#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;
|
|
}
|