Method extract_parts

extern/boost/boost/multiprecision/cpp_dec_float.hpp:1518–1564

template <unsigned Digits10, class ExponentType, class Allocator>
void cpp_dec_float<Digits10, ExponentType, Allocator>::extract_parts(double& mantissa, ExponentType& exponent) const
{
   // Extract the approximate parts mantissa and base-10 exponent from the input cpp_dec_float<Digits10, ExponentType, Allocator> value x.

   // Extracts the mantissa and exponent.
   exponent = exp;

   std::uint32_t p10  = static_cast<std::uint32_t>(1u);
   std::uint32_t test = data[0u];

   for (;;)
   {
      test /= static_cast<std::uint32_t>(10u);

      if (test == static_cast<std::uint32_t>(0u))
      {
         break;
      }

      p10 *= static_cast<std::uint32_t>(10u);
      ++exponent;
   }

   // Establish the upper bound of limbs for extracting the double.
   const int max_elem_in_double_count = static_cast<int>(static_cast<std::int32_t>(std::numeric_limits<double>::digits10) / cpp_dec_float_elem_digits10) + (static_cast<int>(static_cast<std::int32_t>(std::numeric_limits<double>::digits10) % cpp_dec_float_elem_digits10) != 0 ? 1 : 0) + 1;

   // And make sure this upper bound stays within bounds of the elems.
   const std::size_t max_elem_extract_count = static_cast<std::size_t>((std::min)(static_cast<std::int32_t>(max_elem_in_double_count), cpp_dec_float_elem_number));

   // Extract into the mantissa the first limb, extracted as a double.
   mantissa     = static_cast<double>(data[0]);
   double scale = 1.0;

   // Extract the rest of the mantissa piecewise from the limbs.
   for (std::size_t i = 1u; i < max_elem_extract_count; i++)
   {
      scale /= static_cast<double>(cpp_dec_float_elem_mask);
      mantissa += (static_cast<double>(data[i]) * scale);
   }

   mantissa /= static_cast<double>(p10);

   if (neg)
   {
      mantissa = -mantissa;
   }
}

template <unsigned Digits10, class ExponentType, class Allocator>
double cpp_dec_float<Digits10, ExponentType, Allocator>::extract_double() const