]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | // Copyright John Maddock 2007. |
2 | // Use, modification and distribution are subject to the | |
3 | // Boost Software License, Version 1.0. (See accompanying file | |
4 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
5 | ||
6 | #ifndef BOOST_MATH_ROUND_HPP | |
7 | #define BOOST_MATH_ROUND_HPP | |
8 | ||
9 | #ifdef _MSC_VER | |
10 | #pragma once | |
11 | #endif | |
12 | ||
13 | #include <boost/math/tools/config.hpp> | |
14 | #include <boost/math/policies/error_handling.hpp> | |
15 | #include <boost/math/special_functions/math_fwd.hpp> | |
16 | #include <boost/math/special_functions/fpclassify.hpp> | |
17 | ||
18 | namespace boost{ namespace math{ | |
19 | ||
20 | namespace detail{ | |
21 | ||
22 | template <class T, class Policy> | |
23 | inline typename tools::promote_args<T>::type round(const T& v, const Policy& pol, const mpl::false_) | |
24 | { | |
25 | BOOST_MATH_STD_USING | |
26 | typedef typename tools::promote_args<T>::type result_type; | |
27 | if(!(boost::math::isfinite)(v)) | |
28 | return policies::raise_rounding_error("boost::math::round<%1%>(%1%)", 0, static_cast<result_type>(v), static_cast<result_type>(v), pol); | |
29 | // | |
30 | // The logic here is rather convoluted, but avoids a number of traps, | |
31 | // see discussion here https://github.com/boostorg/math/pull/8 | |
32 | // | |
33 | if (-0.5 < v && v < 0.5) | |
34 | { | |
35 | // special case to avoid rounding error on the direct | |
36 | // predecessor of +0.5 resp. the direct successor of -0.5 in | |
37 | // IEEE floating point types | |
92f5a8d4 | 38 | return static_cast<result_type>(0); |
7c673cae FG |
39 | } |
40 | else if (v > 0) | |
41 | { | |
42 | // subtract v from ceil(v) first in order to avoid rounding | |
43 | // errors on largest representable integer numbers | |
44 | result_type c(ceil(v)); | |
45 | return 0.5 < c - v ? c - 1 : c; | |
46 | } | |
47 | else | |
48 | { | |
49 | // see former branch | |
50 | result_type f(floor(v)); | |
51 | return 0.5 < v - f ? f + 1 : f; | |
52 | } | |
53 | } | |
54 | template <class T, class Policy> | |
55 | inline typename tools::promote_args<T>::type round(const T& v, const Policy&, const mpl::true_) | |
56 | { | |
57 | return v; | |
58 | } | |
59 | ||
60 | } // namespace detail | |
61 | ||
62 | template <class T, class Policy> | |
63 | inline typename tools::promote_args<T>::type round(const T& v, const Policy& pol) | |
64 | { | |
65 | return detail::round(v, pol, mpl::bool_<detail::is_integer_for_rounding<T>::value>()); | |
66 | } | |
67 | template <class T> | |
68 | inline typename tools::promote_args<T>::type round(const T& v) | |
69 | { | |
70 | return round(v, policies::policy<>()); | |
71 | } | |
72 | // | |
73 | // The following functions will not compile unless T has an | |
74 | // implicit convertion to the integer types. For user-defined | |
75 | // number types this will likely not be the case. In that case | |
76 | // these functions should either be specialized for the UDT in | |
77 | // question, or else overloads should be placed in the same | |
78 | // namespace as the UDT: these will then be found via argument | |
79 | // dependent lookup. See our concept archetypes for examples. | |
80 | // | |
81 | template <class T, class Policy> | |
82 | inline int iround(const T& v, const Policy& pol) | |
83 | { | |
84 | BOOST_MATH_STD_USING | |
85 | T r = boost::math::round(v, pol); | |
86 | if((r > (std::numeric_limits<int>::max)()) || (r < (std::numeric_limits<int>::min)())) | |
87 | return static_cast<int>(policies::raise_rounding_error("boost::math::iround<%1%>(%1%)", 0, v, 0, pol)); | |
88 | return static_cast<int>(r); | |
89 | } | |
90 | template <class T> | |
91 | inline int iround(const T& v) | |
92 | { | |
93 | return iround(v, policies::policy<>()); | |
94 | } | |
95 | ||
96 | template <class T, class Policy> | |
97 | inline long lround(const T& v, const Policy& pol) | |
98 | { | |
99 | BOOST_MATH_STD_USING | |
100 | T r = boost::math::round(v, pol); | |
101 | if((r > (std::numeric_limits<long>::max)()) || (r < (std::numeric_limits<long>::min)())) | |
102 | return static_cast<long int>(policies::raise_rounding_error("boost::math::lround<%1%>(%1%)", 0, v, 0L, pol)); | |
103 | return static_cast<long int>(r); | |
104 | } | |
105 | template <class T> | |
106 | inline long lround(const T& v) | |
107 | { | |
108 | return lround(v, policies::policy<>()); | |
109 | } | |
110 | ||
111 | #ifdef BOOST_HAS_LONG_LONG | |
112 | ||
113 | template <class T, class Policy> | |
114 | inline boost::long_long_type llround(const T& v, const Policy& pol) | |
115 | { | |
116 | BOOST_MATH_STD_USING | |
117 | T r = boost::math::round(v, pol); | |
118 | if((r > (std::numeric_limits<boost::long_long_type>::max)()) || (r < (std::numeric_limits<boost::long_long_type>::min)())) | |
119 | 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)); | |
120 | return static_cast<boost::long_long_type>(r); | |
121 | } | |
122 | template <class T> | |
123 | inline boost::long_long_type llround(const T& v) | |
124 | { | |
125 | return llround(v, policies::policy<>()); | |
126 | } | |
127 | ||
128 | #endif | |
129 | ||
130 | }} // namespaces | |
131 | ||
132 | #endif // BOOST_MATH_ROUND_HPP |