mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-25 09:18:54 -05:00
134 lines
3.8 KiB
C++
134 lines
3.8 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
|
|
// Copyright (C) 2020 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
|
|
// Copyright (C) 2020 Jon Beniston, M7RCE <jon@beniston.com> //
|
|
// //
|
|
// 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/>. //
|
|
///////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#ifndef INCLUDE_CRC_H
|
|
#define INCLUDE_CRC_H
|
|
|
|
#include <stdint.h>
|
|
|
|
#include "export.h"
|
|
|
|
// Class to calculate arbitrary CRCs (up to 32-bits)
|
|
class SDRBASE_API crc
|
|
{
|
|
public:
|
|
// Create and initialise CRC with specified polynomial and parameters
|
|
crc(int poly_bits, uint32_t polynomial, bool msb_first, uint32_t init_value, uint32_t final_xor) :
|
|
m_polynomial(polynomial),
|
|
m_poly_bits(poly_bits),
|
|
m_msb_first(msb_first),
|
|
m_init_value(init_value),
|
|
m_final_xor(final_xor)
|
|
{
|
|
// Reverse polynomial for LSB first
|
|
if (!msb_first)
|
|
{
|
|
int shift;
|
|
|
|
shift = 32 - m_poly_bits;
|
|
m_polynomial_rev = reverse (m_polynomial << shift, 32);
|
|
}
|
|
// Create LUT
|
|
for (int i = 0; i < 256; i++)
|
|
{
|
|
m_crc = 0;
|
|
calculate(i, 8);
|
|
m_lut[i] = m_crc;
|
|
}
|
|
init();
|
|
}
|
|
|
|
// Initialise CRC state
|
|
void init()
|
|
{
|
|
m_crc = m_init_value;
|
|
}
|
|
|
|
// Calculate CRC for supplied data
|
|
void calculate(uint32_t data, int data_bits);
|
|
void calculate(const uint8_t *data, int length);
|
|
|
|
// Get final CRC
|
|
uint32_t get()
|
|
{
|
|
uint32_t t;
|
|
|
|
t = m_final_xor ^ m_crc;
|
|
return t;
|
|
}
|
|
|
|
private:
|
|
static uint32_t reverse(uint32_t val, int bits);
|
|
|
|
uint32_t m_crc;
|
|
uint32_t m_polynomial;
|
|
uint32_t m_polynomial_rev;
|
|
uint32_t m_poly_bits;
|
|
bool m_msb_first;
|
|
uint32_t m_init_value;
|
|
uint32_t m_final_xor;
|
|
uint32_t m_lut[256];
|
|
};
|
|
|
|
class SDRBASE_API crc16ansi : public crc
|
|
{
|
|
public:
|
|
crc16ansi() : crc(16, 0x8005, false, 0x0000, 0) {}
|
|
};
|
|
|
|
class SDRBASE_API crc16ccitt : public crc
|
|
{
|
|
public:
|
|
crc16ccitt() : crc(16, 0x1021, true, 0xffff, 0) {}
|
|
};
|
|
|
|
class SDRBASE_API crc16itut : public crc
|
|
{
|
|
public:
|
|
crc16itut() : crc(16, 0x1021, false, 0x0000, 0) {}
|
|
};
|
|
|
|
class SDRBASE_API crc16x25 : public crc
|
|
{
|
|
public:
|
|
crc16x25() : crc(16, 0x1021, false, 0xffff, 0xffff) {}
|
|
};
|
|
|
|
class SDRBASE_API crc32 : public crc
|
|
{
|
|
public:
|
|
crc32() : crc(32, 0x04C11DB7, false, 0xffffffff, 0xffffffff) {}
|
|
};
|
|
|
|
// Should probably try to use SSE 4.2's CRC32C instruction if available
|
|
// See _mm_crc32_u8 and _mm_crc32_u64 intrinsics
|
|
class SDRBASE_API crc32c : public crc
|
|
{
|
|
public:
|
|
crc32c() : crc(32, 0x1EDC6F41, false, 0xffffffff, 0) {}
|
|
};
|
|
|
|
// ADS-B - https://mode-s.org/decode/adsb/introduction.html
|
|
class SDRBASE_API crcadsb : public crc
|
|
{
|
|
public:
|
|
crcadsb() : crc(24, 0xfff409, true, 0, 0) {}
|
|
};
|
|
|
|
#endif
|