rescale.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
Copyright(c) 2021 John Wellbelove
 
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#ifndef ETL_RESCALE_INCLUDED
#define ETL_RESCALE_INCLUDED
 
#include "platform.h"
#include "algorithm.h"
#include "functional.h"
#include "type_traits.h"
 
// #include <math.h>
#include <stdint.h>
 
namespace etl
{
  //***************************************************************************
  //***************************************************************************
  template <typename TInput, typename TOutput>
  class rescale : public etl::unary_function<TOutput, TInput>
  {
  public:
 
    //*****************************************************************
    //*****************************************************************
    rescale(TInput input_min_value_, TInput input_max_value_, TOutput output_min_value_, TOutput output_max_value_)
      : input_min_value(input_min_value_)
      , output_min_value(output_min_value_)
      , output_max_value(output_max_value_)
      , multiplier(double(output_max_value_ - output_min_value_) / double(input_max_value_ - input_min_value_))
    {
    }
 
    //*****************************************************************
    //*****************************************************************
    TOutput operator()(TInput value) const
    {
      return TOutput(((value - input_min_value) * multiplier)) + output_min_value;
    }
 
  private:
 
    const TInput  input_min_value;
    const TOutput output_min_value;
    const TOutput output_max_value;
    double        multiplier;
  };
} // namespace etl
 
#endif