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			109 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			109 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| ///////////////////////////////////////////////////////////////////////////////////
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| // Copyright (C) 2020 Jon Beniston, M7RCE                                        //
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| //                                                                               //
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| // This program is free software; you can redistribute it and/or modify          //
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| // it under the terms of the GNU General Public License as published by          //
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| // the Free Software Foundation as version 3 of the License, or                  //
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| // (at your option) any later version.                                           //
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| //                                                                               //
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| // This program is distributed in the hope that it will be useful,               //
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| // but WITHOUT ANY WARRANTY; without even the implied warranty of                //
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| // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
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| // GNU General Public License V3 for more details.                               //
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| //                                                                               //
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| // You should have received a copy of the GNU General Public License             //
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| // along with this program. If not, see <http://www.gnu.org/licenses/>.          //
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| ///////////////////////////////////////////////////////////////////////////////////
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| 
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| #ifndef INCLUDE_CRC_H
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| #define INCLUDE_CRC_H
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| 
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| #include <stdint.h>
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| 
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| #include "export.h"
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| 
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| // Class to calculate arbitrary CRCs (up to 32-bits)
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| class SDRBASE_API crc
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| {
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| public:
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|     // Create and initialise CRC with specified polynomial and parameters
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|     crc(int poly_bits, uint32_t polynomial, bool msb_first, uint32_t init_value, uint32_t final_xor) :
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|         m_poly_bits(poly_bits),
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|         m_polynomial(polynomial),
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|         m_msb_first(msb_first),
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|         m_init_value(init_value),
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|         m_final_xor(final_xor)
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|     {
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|         int shift;
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| 
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|         shift = 32 - m_poly_bits;
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|         m_polynomial_rev = reverse (m_polynomial << shift, 32);
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|         init();
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|     }
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| 
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|     // Initialise CRC state
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|     void init()
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|     {
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|         m_crc = m_init_value;
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|     }
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| 
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|     // Calculate CRC for supplied data
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|     void calculate(uint32_t data, int data_bits);
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|     void calculate(const uint8_t *data, int length);
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| 
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|     // Get final CRC
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|     uint32_t get()
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|     {
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|         uint32_t t;
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| 
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|         t = m_final_xor ^ m_crc;
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|         if (m_msb_first)
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|             return reverse(t, m_poly_bits);
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|         else
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|             return t;
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|     }
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| 
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| private:
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|     static uint32_t reverse(uint32_t val, int bits);
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| 
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|     uint32_t m_crc;
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|     uint32_t m_polynomial;
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|     uint32_t m_polynomial_rev;
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|     uint32_t m_poly_bits;
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|     bool m_msb_first;
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|     uint32_t m_init_value;
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|     uint32_t m_final_xor;
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| };
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| 
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| class SDRBASE_API crc16ansi : public crc
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| {
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| public:
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|     crc16ansi() : crc(16, 0x8005, false, 0x0000, 0) {}
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| };
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| 
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| class SDRBASE_API crc16ccitt : public crc
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| {
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| public:
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|     crc16ccitt() : crc(16, 0x1021, true, 0xffff, 0) {}
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| };
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| 
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| class SDRBASE_API crc16x25 : public crc
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| {
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| public:
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|     crc16x25() : crc(16, 0x1021, false, 0xffff, 0xffff) {}
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| };
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| 
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| class SDRBASE_API crc32 : public crc
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| {
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| public:
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|     crc32() : crc(32, 0x04C11DB7, false, 0xffffffff, 0xffffffff) {}
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| };
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| 
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| class SDRBASE_API crc32c : public crc
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| {
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| public:
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|     crc32c() : crc(32, 0x1EDC6F41, false, 0xffffffff, 0) {}
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| };
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| 
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| #endif
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