GY-63_MS5611/libraries/Fletcher/Fletcher32.cpp
2023-01-17 19:28:45 +01:00

82 lines
1.5 KiB
C++

//
// FILE: Fletcher32.cpp
// AUTHOR: Rob Tillaart, Daniel Mohr
// PURPOSE: Arduino class for Fletcher32
// URL: https://github.com/RobTillaart/Fletcher
#include "Fletcher32.h"
// UINT16_MAX = 65535UL = ((((uint32_t) 1) << 16) - 1)
#define FLETCHER_32 UINT16_MAX
Fletcher32::Fletcher32()
{
begin();
}
void Fletcher32::begin(uint16_t s1, uint16_t s2)
{
_s1 = (s1 == FLETCHER_32) ? 0 : s1;
_s2 = (s2 == FLETCHER_32) ? 0 : s2;
_count = 0;
}
void Fletcher32::add(uint16_t value)
{
_count++;
#ifdef ARDUINO_ARCH_AVR
unsigned int t = _s1;
// Serial.println("__builtin_uadd_overflow");
if (__builtin_uadd_overflow(t, value, &t)) {
t++;
}
_s1 = t;
t = _s2;
if (__builtin_uadd_overflow(t, _s1, &t)) {
t++;
}
_s2 = t;
#elif defined(ARDUINO_ARCH_SAMD) || defined(ESP32) || defined(ESP8266)
_s1 += value;
_s1 = (_s1 & FLETCHER_32) + (_s1 >> 16);
_s2 += _s1;
_s2 = (_s2 & FLETCHER_32) + (_s2 >> 16);
#else
_s1 += value;
if (_s1 >= FLETCHER_32) _s1 -= FLETCHER_32;
_s2 += _s1;
if (_s2 >= FLETCHER_32) _s2 -= FLETCHER_32;
#endif
}
// NOTE: padding with zero's error
//
void Fletcher32::add(const uint16_t * array, uint16_t length)
{
while (length--)
{
add(*array++);
}
}
uint32_t Fletcher32::getFletcher()
{
if (_s1 >= FLETCHER_32) _s1 -= FLETCHER_32;
if (_s2 >= FLETCHER_32) _s2 -= FLETCHER_32;
return (((uint32_t)_s2) << 16) | _s1;
};
uint32_t Fletcher32::count()
{
return _count;
};
// -- END OF FILE --