comparison DEPENDENCIES/generic/include/boost/multiprecision/detail/generic_interconvert.hpp @ 16:2665513ce2d3

Add boost headers

+///////////////////////////////////////////////////////////////////////////////
+//  Copyright 2011 John Maddock. Distributed under the Boost
+//  Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_MP_GENERIC_INTERCONVERT_HPP
+#define BOOST_MP_GENERIC_INTERCONVERT_HPP
+
+#include <boost/multiprecision/detail/default_ops.hpp>
+
+namespace boost{ namespace multiprecision{ namespace detail{
+
+template <class To, class From>
+void generic_interconvert(To& to, const From& from, const mpl::int_<number_kind_floating_point>& /*to_type*/, const mpl::int_<number_kind_integer>& /*from_type*/)
+{
+   using default_ops::eval_get_sign;
+   using default_ops::eval_bitwise_and;
+   using default_ops::eval_convert_to;
+   using default_ops::eval_right_shift;
+   using default_ops::eval_ldexp;
+   using default_ops::eval_add;
+   // smallest unsigned type handled natively by "From" is likely to be it's limb_type:
+   typedef typename canonical<unsigned char, From>::type   limb_type;
+   // get the corresponding type that we can assign to "To":
+   typedef typename canonical<limb_type, To>::type         to_type;
+   From t(from);
+   bool is_neg = eval_get_sign(t) < 0;
+   if(is_neg)
+      t.negate();
+   // Pick off the first limb:
+   limb_type limb;
+   limb_type mask = ~static_cast<limb_type>(0);
+   From fl;
+   eval_bitwise_and(fl, t, mask);
+   eval_convert_to(&limb, fl);
+   to = static_cast<to_type>(limb);
+   eval_right_shift(t, std::numeric_limits<limb_type>::digits);
+   //
+   // Then keep picking off more limbs until "t" is zero:
+   //
+   To l;
+   unsigned shift = std::numeric_limits<limb_type>::digits;
+   while(!eval_is_zero(t))
+   {
+      eval_bitwise_and(fl, t, mask);
+      eval_convert_to(&limb, fl);
+      l = static_cast<to_type>(limb);
+      eval_right_shift(t, std::numeric_limits<limb_type>::digits);
+      eval_ldexp(l, l, shift);
+      eval_add(to, l);
+      shift += std::numeric_limits<limb_type>::digits;
+   }
+   //
+   // Finish off by setting the sign:
+   //
+   if(is_neg)
+      to.negate();
+}
+
+template <class To, class From>
+void generic_interconvert(To& to, const From& from, const mpl::int_<number_kind_integer>& /*to_type*/, const mpl::int_<number_kind_integer>& /*from_type*/)
+{
+   using default_ops::eval_get_sign;
+   using default_ops::eval_bitwise_and;
+   using default_ops::eval_convert_to;
+   using default_ops::eval_right_shift;
+   using default_ops::eval_left_shift;
+   using default_ops::eval_bitwise_or;
+   using default_ops::eval_is_zero;
+   // smallest unsigned type handled natively by "From" is likely to be it's limb_type:
+   typedef typename canonical<unsigned char, From>::type   limb_type;
+   // get the corresponding type that we can assign to "To":
+   typedef typename canonical<limb_type, To>::type         to_type;
+   From t(from);
+   bool is_neg = eval_get_sign(t) < 0;
+   if(is_neg)
+      t.negate();
+   // Pick off the first limb:
+   limb_type limb;
+   limb_type mask = static_cast<limb_type>(~static_cast<limb_type>(0));
+   From fl;
+   eval_bitwise_and(fl, t, mask);
+   eval_convert_to(&limb, fl);
+   to = static_cast<to_type>(limb);
+   eval_right_shift(t, std::numeric_limits<limb_type>::digits);
+   //
+   // Then keep picking off more limbs until "t" is zero:
+   //
+   To l;
+   unsigned shift = std::numeric_limits<limb_type>::digits;
+   while(!eval_is_zero(t))
+   {
+      eval_bitwise_and(fl, t, mask);
+      eval_convert_to(&limb, fl);
+      l = static_cast<to_type>(limb);
+      eval_right_shift(t, std::numeric_limits<limb_type>::digits);
+      eval_left_shift(l, shift);
+      eval_bitwise_or(to, l);
+      shift += std::numeric_limits<limb_type>::digits;
+   }
+   //
+   // Finish off by setting the sign:
+   //
+   if(is_neg)
+      to.negate();
+}
+
+template <class To, class From>
+void generic_interconvert(To& to, const From& from, const mpl::int_<number_kind_floating_point>& /*to_type*/, const mpl::int_<number_kind_floating_point>& /*from_type*/)
+{
+#ifdef BOOST_MSVC
+#pragma warning(push)
+#pragma warning(disable:4127)
+#endif
+   //
+   // The code here only works when the radix of "From" is 2, we could try shifting by other
+   // radixes but it would complicate things.... use a string conversion when the radix is other
+   // than 2:
+   //
+   if(std::numeric_limits<number<From> >::radix != 2)
+   {
+      to = from.str(0, std::ios_base::fmtflags()).c_str();
+      return;
+   }
+
+
+   typedef typename canonical<unsigned char, To>::type ui_type;
+
+   using default_ops::eval_fpclassify;
+   using default_ops::eval_add;
+   using default_ops::eval_subtract;
+   using default_ops::eval_convert_to;
+
+   //
+   // First classify the input, then handle the special cases:
+   //
+   int c = eval_fpclassify(from);
+
+   if(c == FP_ZERO) 
+   {
+      to = ui_type(0);
+      return;
+   }
+   else if(c == FP_NAN)
+   {
+      to = "nan";
+      return;
+   }
+   else if(c == FP_INFINITE)
+   {
+      to = "inf";
+      if(eval_get_sign(from) < 0)
+         to.negate();
+      return;
+   }
+
+   typename From::exponent_type e;
+   From f, term;
+   to = ui_type(0);
+
+   eval_frexp(f, from, &e);
+
+   static const int shift = std::numeric_limits<boost::intmax_t>::digits - 1;
+
+   while(!eval_is_zero(f))
+   {
+      // extract int sized bits from f:
+      eval_ldexp(f, f, shift);
+      eval_floor(term, f);
+      e -= shift;
+      eval_ldexp(to, to, shift);
+      typename boost::multiprecision::detail::canonical<boost::intmax_t, To>::type ll;
+      eval_convert_to(&ll, term);
+      eval_add(to, ll);
+      eval_subtract(f, term);
+   }
+   typedef typename To::exponent_type to_exponent;
+   if((e > (std::numeric_limits<to_exponent>::max)()) || (e < (std::numeric_limits<to_exponent>::min)()))
+   {
+      to = "inf";
+      if(eval_get_sign(from) < 0)
+         to.negate();
+      return;
+   }
+   eval_ldexp(to, to, static_cast<to_exponent>(e));
+#ifdef BOOST_MSVC
+#pragma warning(pop)
+#endif
+}
+
+template <class To, class From>
+void generic_interconvert(To& to, const From& from, const mpl::int_<number_kind_rational>& /*to_type*/, const mpl::int_<number_kind_rational>& /*from_type*/)
+{
+   typedef typename component_type<number<To> >::type     to_component_type;
+
+   number<From> t(from);
+   to_component_type n(numerator(t)), d(denominator(t));
+   using default_ops::assign_components;
+   assign_components(to, n.backend(), d.backend());
+}
+
+template <class To, class From>
+void generic_interconvert(To& to, const From& from, const mpl::int_<number_kind_rational>& /*to_type*/, const mpl::int_<number_kind_integer>& /*from_type*/)
+{
+   typedef typename component_type<number<To> >::type     to_component_type;
+
+   number<From> t(from);
+   to_component_type n(t), d(1);
+   using default_ops::assign_components;
+   assign_components(to, n.backend(), d.backend());
+}
+
+template <class To, class From>
+void generic_interconvert(To& to, const From& from, const mpl::int_<number_kind_floating_point>& /*to_type*/, const mpl::int_<number_kind_rational>& /*from_type*/)
+{
+   typedef typename component_type<number<From> >::type   from_component_type;
+   using default_ops::eval_divide;
+
+   number<From> t(from);
+   from_component_type n(numerator(t)), d(denominator(t));
+   number<To> fn(n), fd(d);
+   eval_divide(to, fn.backend(), fd.backend());
+}
+
+}}} // namespaces
+
+#endif  // BOOST_MP_GENERIC_INTERCONVERT_HPP
+