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

#pragma once
//
//    FILE: MultiMap.h
//  AUTHOR: Rob Tillaart
// VERSION: 0.1.6
//    DATE: 2011-01-26
// PURPOSE: Arduino library for fast non-linear mapping or interpolation of values
//     URL: https://github.com/RobTillaart/MultiMap
//     URL: http://playground.arduino.cc/Main/MultiMap



#define MULTIMAP_LIB_VERSION                (F("0.1.6"))


#include "Arduino.h"


// note: the in array should have increasing values
template<typename T>
T multiMap(T value, T* _in, T* _out, uint8_t size)
{
    // take care the value is within range
    // value = constrain(value, _in[0], _in[size-1]);
    if (value <= _in[0]) return _out[0];
    if (value >= _in[size-1]) return _out[size-1];

    // search right interval
    uint8_t pos = 1;  // _in[0] already tested
    while(value > _in[pos]) pos++;

    // this will handle all exact "points" in the _in array
    if (value == _in[pos]) return _out[pos];

    // interpolate in the right segment for the rest
    return (value - _in[pos-1]) * (_out[pos] - _out[pos-1]) / (_in[pos] - _in[pos-1]) + _out[pos-1];
}


/*
//  speed optimized version if inputs do not change often e.g.  2 2 2 2 2 3 3 3 3 5 5 5 5 5 5 8 8 8 8 5 5 5 5 5 
//  implements a minimal cache
//
//  note: the in array should have increasing values

template<typename T>
T multiMap(T value, T* _in, T* _out, uint8_t size)
{
  static T lastvalue = -1;
  static T cache = -1;  

  if (value == lastvalue)
  {
    return cache;
  }
  lastvalue = value;

  // take care the value is within range
  // value = constrain(value, _in[0], _in[size-1]);
  if (value <= _in[0])
  {
    cache = _out[0];
  }
  else if (value >= _in[size-1])
  {
    cache = _out[size-1];
  }
  else
  {
    // search right interval; index 0 _in[0] already tested
    uint8_t pos = 1;  
    while(value > _in[pos]) pos++;
    
    // this will handle all exact "points" in the _in array
    if (value == _in[pos]) 
    {
      cache = _out[pos];
    }
    else
    {
      // interpolate in the right segment for the rest
      cache = (value - _in[pos-1]) * (_out[pos] - _out[pos-1]) / (_in[pos] - _in[pos-1]) + _out[pos-1];
    }
  }
  return cache;
}
*/


// -- END OF FILE --