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81 lines
1.4 KiB
C++
81 lines
1.4 KiB
C++
//
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// FILE: Fletcher16.cpp
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// AUTHOR: Rob Tillaart, Daniel Mohr
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// PURPOSE: Arduino class for Fletcher16
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// URL: https://github.com/RobTillaart/Fletcher
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#include "Fletcher16.h"
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// UINT8_MAX = 255 = ((((uint16_t) 1) << 8) - 1)
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#define FLETCHER_16 UINT8_MAX
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Fletcher16::Fletcher16()
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{
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begin();
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}
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void Fletcher16::begin(uint8_t s1, uint8_t s2)
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{
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_s1 = (s1 == FLETCHER_16) ? 0 : s1;
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_s2 = (s2 == FLETCHER_16) ? 0 : s2;
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_count = 0;
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}
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void Fletcher16::add(uint8_t value)
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{
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_count++;
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#if defined(ARDUINO_ARCH_AVR)
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uint8_t t = 0xFF - value;
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if (t >= _s1) _s1 += value;
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else _s1 = _s1 + value + 1;
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t = 0xFF - _s1;
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if (t >= _s2) _s2 += _s1;
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else _s2 = _s2 + _s1 + 1;
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#elif defined(ARDUINO_ARCH_SAMD) || defined(ESP32) || defined(ESP8266)
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_s1 += value;
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_s1 = (_s1 & FLETCHER_16) + (_s1 >> 8);
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_s2 += _s1;
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_s2 = (_s2 & FLETCHER_16) + (_s2 >> 8);
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#else
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// REFERENCE
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_s1 += value;
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if (_s1 >= FLETCHER_16) _s1 -= FLETCHER_16;
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_s2 += _s1;
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if (_s2 >= FLETCHER_16) _s2 -= FLETCHER_16;
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#endif
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}
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void Fletcher16::add(const uint8_t * array, uint16_t length)
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{
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while (length--)
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{
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add(*array++);
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}
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}
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uint16_t Fletcher16::getFletcher()
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{
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if (_s1 >= FLETCHER_16) _s1 -= FLETCHER_16;
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if (_s2 >= FLETCHER_16) _s2 -= FLETCHER_16;
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return (((uint16_t)_s2) << 8) | _s1;
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};
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uint32_t Fletcher16::count()
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{
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return _count;
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};
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// -- END OF FILE --
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