boost/numeric/interval/rounding.hpp

   1 /* Boost interval/rounding.hpp template implementation file
   2  *
   3  * Copyright 2002-2003 Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion
   4  *
   5  * Distributed under the Boost Software License, Version 1.0.
   6  * (See accompanying file LICENSE_1_0.txt or
   7  * copy at http://www.boost.org/LICENSE_1_0.txt)
   8  */
   9
  10 #ifndef BOOST_NUMERIC_INTERVAL_ROUNDING_HPP
  11 #define BOOST_NUMERIC_INTERVAL_ROUNDING_HPP
  12
  13 namespace boost {
  14 namespace numeric {
  15 namespace interval_lib {
  16
  17 /*
  18  * Default rounding_control class (does nothing)
  19  */
  20
  21 template<class T>
  22 struct rounding_control
  23 {
  24   typedef int rounding_mode;
  25   static void get_rounding_mode(rounding_mode&) {}
  26   static void set_rounding_mode(rounding_mode)  {}
  27   static void upward()     {}
  28   static void downward()   {}
  29   static void to_nearest() {}
  30   static const T& to_int(const T& x)         { return x; }
  31   static const T& force_rounding(const T& x) { return x; }
  32 };
  33
  34 /*
  35  * A few rounding control classes (exact/std/opp: see documentation)
  36  *   rounded_arith_* control the rounding of the arithmetic operators
  37  *   rounded_transc_* control the rounding of the transcendental functions
  38  */
  39
  40 template<class T, class Rounding = rounding_control<T> >
  41 struct rounded_arith_exact;
  42
  43 template<class T, class Rounding = rounding_control<T> >
  44 struct rounded_arith_std;
  45
  46 template<class T, class Rounding = rounding_control<T> >
  47 struct rounded_arith_opp;
  48
  49 template<class T, class Rounding>
  50 struct rounded_transc_dummy;
  51
  52 template<class T, class Rounding = rounded_arith_exact<T> >
  53 struct rounded_transc_exact;
  54
  55 template<class T, class Rounding = rounded_arith_std<T> >
  56 struct rounded_transc_std;
  57
  58 template<class T, class Rounding = rounded_arith_opp<T> >
  59 struct rounded_transc_opp;
  60
  61 /*
  62  * State-saving classes: allow to set and reset rounding control
  63  */
  64
  65 namespace detail {
  66
  67 template<class Rounding>
  68 struct save_state_unprotected: Rounding
  69 {
  70   typedef save_state_unprotected<Rounding> unprotected_rounding;
  71 };
  72
  73 } // namespace detail
  74
  75 template<class Rounding>
  76 struct save_state: Rounding
  77 {
  78   typename Rounding::rounding_mode mode;
  79   save_state() {
  80     this->get_rounding_mode(mode);
  81     this->init();
  82   }
  83   ~save_state() { this->set_rounding_mode(mode); }
  84   typedef detail::save_state_unprotected<Rounding> unprotected_rounding;
  85 };
  86
  87 template<class Rounding>
  88 struct save_state_nothing: Rounding
  89 {
  90   typedef save_state_nothing<Rounding> unprotected_rounding;
  91 };
  92
  93 template<class T>
  94 struct rounded_math: save_state_nothing<rounded_arith_exact<T> >
  95 {};
  96
  97 } // namespace interval_lib
  98 } // namespace numeric
  99 } // namespace boost
 100
 101 #endif // BOOST_NUMERIC_INTERVAL_ROUNDING_HPP