GY-63_MS5611/libraries/randomHelpers/randomHelpers.h

#pragma once
//
//    FILE: randomHelpers.h
//  AUTHOR: Rob Tillaart
// VERSION: 0.2.4
// PURPOSE: Arduino library with helper function for faster random bits
//     URL: https://github.com/RobTillaart/randomHelpers


#include "Arduino.h"

#define RANDOM_HELPERS_VERSION                (F("0.2.4"))


// the idea is to have one buffer ( __randomBuffer) which holds 32 random bits. 
// Every call fetches bits from that buffer and if it does not hold enough 
// bits any more it fills the buffer first. This way the relative expensive 
// calls to random() which produces a 32 bit number are minimized in an
// efficient way.
//
// TBD: put it in a class ?


///////////////////////////////////////////////////////////////////////////
//
// An example of a simple pseudo-random number generator is the 
// Multiply-with-carry method invented by George Marsaglia.
// it has two initializers (not zero) which can be changed 
// to seed the generator.
//

uint32_t Marsaglia();

bool seedMarsaglia(uint32_t a, uint32_t b);

uint32_t getRandom32();

bool getRandom1();

// typical use 
bool inline flipCoin();

uint8_t getRandom4();

uint8_t getRandom5();

uint8_t getRandom6();

// typical use
uint8_t throwDice();

uint8_t getRandom8();

uint16_t getRandom16();

uint32_t getRandom24();

uint64_t getRandom64();

/*
// works well for 1..16; but above it is worse
uint32_t getRandomBits(uint8_t n)
{
  if (__randomIdx < n)
  {
    __randomBuffer = getRandom32();
    __randomIdx = 32;
  }
  uint32_t rv = __randomBuffer & ((1UL << n) - 1);
  __randomBuffer >>= n;
  __randomIdx -= n;
  return rv;
}
*/


// n = 1..31
// TODO: performance gain too low for n > 16
uint32_t getRandomBits(uint8_t n);



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