Chris@16: //  Copyright John Maddock 2007.
Chris@16: //  Use, modification and distribution are subject to the
Chris@16: //  Boost Software License, Version 1.0. (See accompanying file
Chris@16: //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_MATH_ROUND_HPP
Chris@16: #define BOOST_MATH_ROUND_HPP
Chris@16: 
Chris@16: #ifdef _MSC_VER
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/math/tools/config.hpp>
Chris@16: #include <boost/math/policies/error_handling.hpp>
Chris@101: #include <boost/math/special_functions/math_fwd.hpp>
Chris@16: #include <boost/math/special_functions/fpclassify.hpp>
Chris@16: 
Chris@16: namespace boost{ namespace math{
Chris@16: 
Chris@101: namespace detail{
Chris@101: 
Chris@101: template <class T, class Policy>
Chris@101: inline typename tools::promote_args<T>::type round(const T& v, const Policy& pol, const mpl::false_)
Chris@101: {
Chris@101:    BOOST_MATH_STD_USING
Chris@101:       typedef typename tools::promote_args<T>::type result_type;
Chris@101:    if(!(boost::math::isfinite)(v))
Chris@101:       return policies::raise_rounding_error("boost::math::round<%1%>(%1%)", 0, static_cast<result_type>(v), static_cast<result_type>(v), pol);
Chris@101:    //
Chris@101:    // The logic here is rather convoluted, but avoids a number of traps,
Chris@101:    // see discussion here https://github.com/boostorg/math/pull/8
Chris@101:    //
Chris@101:    if (-0.5 < v && v < 0.5)
Chris@101:    {
Chris@101:       // special case to avoid rounding error on the direct
Chris@101:       // predecessor of +0.5 resp. the direct successor of -0.5 in
Chris@101:       // IEEE floating point types
Chris@101:       return 0;
Chris@101:    }
Chris@101:    else if (v > 0)
Chris@101:    {
Chris@101:       // subtract v from ceil(v) first in order to avoid rounding
Chris@101:       // errors on largest representable integer numbers
Chris@101:       result_type c(ceil(v));
Chris@101:       return 0.5 < c - v ? c - 1 : c;
Chris@101:    }
Chris@101:    else
Chris@101:    {
Chris@101:       // see former branch
Chris@101:       result_type f(floor(v));
Chris@101:       return 0.5 < v - f ? f + 1 : f;
Chris@101:    }
Chris@101: }
Chris@101: template <class T, class Policy>
Chris@101: inline typename tools::promote_args<T>::type round(const T& v, const Policy&, const mpl::true_)
Chris@101: {
Chris@101:    return v;
Chris@101: }
Chris@101: 
Chris@101: } // namespace detail
Chris@101: 
Chris@16: template <class T, class Policy>
Chris@16: inline typename tools::promote_args<T>::type round(const T& v, const Policy& pol)
Chris@16: {
Chris@101:    return detail::round(v, pol, mpl::bool_<detail::is_integer_for_rounding<T>::value>());
Chris@16: }
Chris@16: template <class T>
Chris@16: inline typename tools::promote_args<T>::type round(const T& v)
Chris@16: {
Chris@16:    return round(v, policies::policy<>());
Chris@16: }
Chris@16: //
Chris@16: // The following functions will not compile unless T has an
Chris@16: // implicit convertion to the integer types.  For user-defined
Chris@16: // number types this will likely not be the case.  In that case
Chris@16: // these functions should either be specialized for the UDT in
Chris@16: // question, or else overloads should be placed in the same 
Chris@16: // namespace as the UDT: these will then be found via argument
Chris@16: // dependent lookup.  See our concept archetypes for examples.
Chris@16: //
Chris@16: template <class T, class Policy>
Chris@16: inline int iround(const T& v, const Policy& pol)
Chris@16: {
Chris@16:    BOOST_MATH_STD_USING
Chris@16:    T r = boost::math::round(v, pol);
Chris@16:    if((r > (std::numeric_limits<int>::max)()) || (r < (std::numeric_limits<int>::min)()))
Chris@16:       return static_cast<int>(policies::raise_rounding_error("boost::math::iround<%1%>(%1%)", 0, v, 0, pol));
Chris@16:    return static_cast<int>(r);
Chris@16: }
Chris@16: template <class T>
Chris@16: inline int iround(const T& v)
Chris@16: {
Chris@16:    return iround(v, policies::policy<>());
Chris@16: }
Chris@16: 
Chris@16: template <class T, class Policy>
Chris@16: inline long lround(const T& v, const Policy& pol)
Chris@16: {
Chris@16:    BOOST_MATH_STD_USING
Chris@16:    T r = boost::math::round(v, pol);
Chris@16:    if((r > (std::numeric_limits<long>::max)()) || (r < (std::numeric_limits<long>::min)()))
Chris@16:       return static_cast<long int>(policies::raise_rounding_error("boost::math::lround<%1%>(%1%)", 0, v, 0L, pol));
Chris@16:    return static_cast<long int>(r);
Chris@16: }
Chris@16: template <class T>
Chris@16: inline long lround(const T& v)
Chris@16: {
Chris@16:    return lround(v, policies::policy<>());
Chris@16: }
Chris@16: 
Chris@16: #ifdef BOOST_HAS_LONG_LONG
Chris@16: 
Chris@16: template <class T, class Policy>
Chris@16: inline boost::long_long_type llround(const T& v, const Policy& pol)
Chris@16: {
Chris@16:    BOOST_MATH_STD_USING
Chris@16:    T r = boost::math::round(v, pol);
Chris@16:    if((r > (std::numeric_limits<boost::long_long_type>::max)()) || (r < (std::numeric_limits<boost::long_long_type>::min)()))
Chris@16:       return static_cast<boost::long_long_type>(policies::raise_rounding_error("boost::math::llround<%1%>(%1%)", 0, v, static_cast<boost::long_long_type>(0), pol));
Chris@16:    return static_cast<boost::long_long_type>(r);
Chris@16: }
Chris@16: template <class T>
Chris@16: inline boost::long_long_type llround(const T& v)
Chris@16: {
Chris@16:    return llround(v, policies::policy<>());
Chris@16: }
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: }} // namespaces
Chris@16: 
Chris@16: #endif // BOOST_MATH_ROUND_HPP