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https://github.com/RobTillaart/Arduino.git
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97 lines
2.3 KiB
C++
97 lines
2.3 KiB
C++
#pragma once
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//
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// FILE: MultiMap.h
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// AUTHOR: Rob Tillaart
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// VERSION: 0.1.4
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// DATE: 2011-01-26
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// PURPOSE: Arduino library for fast non-linear mapping or interpolation of values
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// URL: https://github.com/RobTillaart/MultiMap
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// URL: http://playground.arduino.cc/Main/MultiMap
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//
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// HISTORY:
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// 0.0.1 2011-01-26 initial version (see forum)
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// .....
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// 0.1.0 2015-03-29
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// 0.1.1 2020-04-09
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// 0.1.2 2020-06-19 fix library.json
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// 0.1.3 2021-01-02 add arduino-CI
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// 0.1.4 2021-05-27 fix arduino-lint
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#define MULTIMAP_LIB_VERSION (F("0.1.4"))
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#include "Arduino.h"
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// note: the in array should have increasing values
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template<typename T>
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T multiMap(T val, T* _in, T* _out, uint8_t size)
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{
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// take care the value is within range
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// val = constrain(val, _in[0], _in[size-1]);
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if (val <= _in[0]) return _out[0];
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if (val >= _in[size-1]) return _out[size-1];
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// search right interval
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uint8_t pos = 1; // _in[0] allready tested
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while(val > _in[pos]) pos++;
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// this will handle all exact "points" in the _in array
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if (val == _in[pos]) return _out[pos];
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// interpolate in the right segment for the rest
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return (val - _in[pos-1]) * (_out[pos] - _out[pos-1]) / (_in[pos] - _in[pos-1]) + _out[pos-1];
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}
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/*
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* 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
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*
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// note: the in array should have increasing values
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template<typename T>
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T multiMap(T val, T* _in, T* _out, uint8_t size)
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{
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static T lastvalue = -1;
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static T cache = -1;
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if (val == lastvalue)
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{
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return cache;
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}
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lastvalue = val;
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// take care the value is within range
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// val = constrain(val, _in[0], _in[size-1]);
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if (val <= _in[0])
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{
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cache = _out[0];
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}
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else if (val >= _in[size-1])
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{
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cache = _out[size-1];
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}
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else
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{
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// search right interval; index 0 _in[0] already tested
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uint8_t pos = 1;
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while(val > _in[pos]) pos++;
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// this will handle all exact "points" in the _in array
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if (val == _in[pos])
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{
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cache = _out[pos];
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}
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else
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{
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// interpolate in the right segment for the rest
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cache = (val - _in[pos-1]) * (_out[pos] - _out[pos-1]) / (_in[pos] - _in[pos-1]) + _out[pos-1];
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}
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}
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return cache;
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}
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*/
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// -- END OF FILE --
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