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56 lines
872 B
C++
56 lines
872 B
C++
/*
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* Copyright (C) 2014 Pavel Kirienko <pavel.kirienko@gmail.com>
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*/
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#pragma once
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#include <cassert>
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#include <uavcan/stdint.hpp>
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namespace uavcan
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{
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/**
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* CRC-16-CCITT
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* Initial value: 0xFFFF
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* Poly: 0x1021
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* Reverse: no
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* Output xor: 0
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*
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* import crcmod
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* crc = crcmod.predefined.Crc('crc-ccitt-false')
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* crc.update('123456789')
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* crc.hexdigest()
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* '29B1'
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*/
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class TransferCRC
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{
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static const uint16_t Table[256];
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uint16_t value_;
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public:
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enum { NumBytes = 2 };
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TransferCRC()
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: value_(0xFFFF)
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{ }
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void add(uint8_t byte)
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{
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value_ = ((value_ << 8) ^ Table[((value_ >> 8) ^ byte) & 0xFF]) & 0xFFFF;
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}
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void add(const uint8_t* bytes, unsigned len)
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{
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assert(bytes);
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while (len--)
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{
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add(*bytes++);
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}
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}
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uint16_t get() const { return value_; }
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};
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}
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