2023-11-18 06:02:48 -05:00
|
|
|
///////////////////////////////////////////////////////////////////////////////////////
|
|
|
|
|
// Copyright (C) 2019 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
|
|
|
|
|
// //
|
|
|
|
|
// This file is part of LeanSDR Copyright (C) 2016-2018 <pabr@pabr.org>. //
|
|
|
|
|
// //
|
|
|
|
|
// This program is free software; you can redistribute it and/or modify //
|
|
|
|
|
// it under the terms of the GNU General Public License as published by //
|
|
|
|
|
// the Free Software Foundation as version 3 of the License, or //
|
|
|
|
|
// (at your option) any later version. //
|
|
|
|
|
// //
|
|
|
|
|
// This program 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 General Public License V3 for more details. //
|
|
|
|
|
// //
|
|
|
|
|
// You should have received a copy of the GNU General Public License //
|
|
|
|
|
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
|
|
|
|
|
///////////////////////////////////////////////////////////////////////////////////////
|
2019-03-17 16:31:42 -04:00
|
|
|
|
|
|
|
|
#ifndef LEANSDR_CRC_H
|
|
|
|
|
#define LEANSDR_CRC_H
|
|
|
|
|
|
|
|
|
|
#include <stdint.h>
|
|
|
|
|
|
|
|
|
|
#include "leansdr/discrmath.h"
|
|
|
|
|
|
|
|
|
|
namespace leansdr
|
|
|
|
|
{
|
|
|
|
|
|
|
|
|
|
// EN 302 307-1 section 5.1.4 CRC-8 encoder
|
|
|
|
|
|
|
|
|
|
struct crc8_engine
|
|
|
|
|
{
|
|
|
|
|
crc8_engine()
|
|
|
|
|
{
|
|
|
|
|
// Precompute
|
|
|
|
|
// EN 302 307-1 5.1.4 Figure 2
|
|
|
|
|
bitvect<uint8_t, 8> g = POLY_DVBS2_CRC8;
|
|
|
|
|
for (int u = 0; u < 256; ++u)
|
|
|
|
|
{
|
|
|
|
|
uint8_t u8 = u;
|
|
|
|
|
bitvect<uint8_t, 8> c = shiftdivmod(&u8, 1, g);
|
|
|
|
|
table[u] = c.v[0];
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
uint8_t compute(const uint8_t *buf, int len)
|
|
|
|
|
{
|
|
|
|
|
uint8_t c = 0;
|
|
|
|
|
for (; len--; ++buf)
|
|
|
|
|
c = table[c ^ *buf];
|
|
|
|
|
return c;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
private:
|
|
|
|
|
static const uint8_t POLY_DVBS2_CRC8 = 0xd5; // (1)11010101
|
|
|
|
|
uint8_t table[256];
|
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
// CRC-32 ITU V.42 for FINGERPRINT
|
|
|
|
|
|
|
|
|
|
uint32_t crc32(const uint8_t *buf, int len)
|
|
|
|
|
{
|
|
|
|
|
static const uint32_t poly = 0xedb88320;
|
|
|
|
|
uint32_t c = 0xffffffff;
|
|
|
|
|
for (int i = 0; i < len; ++i)
|
|
|
|
|
{
|
|
|
|
|
c ^= buf[i];
|
|
|
|
|
for (int bit = 8; bit--;)
|
|
|
|
|
c = (c & 1) ? (c >> 1) ^ poly : (c >> 1);
|
|
|
|
|
}
|
|
|
|
|
return c ^ 0xffffffff;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
} // namespace leansdr
|
|
|
|
|
|
|
|
|
|
#endif // LEANSDR_CRC_H
|
