CompressedFloatingPointNumbers.cpph

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#include <cmath>
#include <limits>
 
 
template <class T>
void toolbox::multiprecision::decompose(
  const double&  value,
  char&          exponent,
  T&             mantissa
) {
  int    integerExponent;
  double significant = std::frexp(value , &integerExponent);
 
  const int    shiftExponent    = std::numeric_limits<T>::digits-1;
  const double shiftMantissa    = std::pow( 2.0,shiftExponent );
 
  if (integerExponent-shiftExponent <= std::numeric_limits<char>::min()) {
    exponent  = 0;
    mantissa  = 0;
  }
  else {
    exponent  = static_cast<char>( integerExponent-shiftExponent );
    mantissa  = static_cast<T>( std::round(significant*shiftMantissa) );
  }
}
 
 
template <class T>
double toolbox::multiprecision::compose(
  const char&   exponent,
  const T&      mantissa
) {
  return std::ldexp(mantissa,exponent);
}