mirror of
https://github.com/boostorg/safe_numerics.git
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387 lines
13 KiB
C++
387 lines
13 KiB
C++
#ifndef BOOST_NUMERIC_AUTOMATIC_HPP
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#define BOOST_NUMERIC_AUTOMATIC_HPP
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// MS compatible compilers support #pragma once
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#if defined(_MSC_VER) && (_MSC_VER >= 1020)
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# pragma once
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#endif
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// Copyright (c) 2012 Robert Ramey
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// policy which creates results types equal to that of C++ promotions.
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// Using the policy will permit the program to build and run in release
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// mode which is identical to that in debug mode except for the fact
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// that errors aren't trapped.
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#include <limits>
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#include <cstdint> // (u)intmax_t,
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#include <type_traits> // true_type, false_type
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#include <boost/mpl/if.hpp>
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#include <boost/mpl/eval_if.hpp>
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#include <boost/mpl/identity.hpp>
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#include "safe_common.hpp"
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#include "interval.hpp"
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#include "safe_range.hpp"
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namespace boost {
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namespace numeric {
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struct automatic {
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template<class T, class U>
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using calculate_max_t2 =
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typename boost::mpl::if_c<
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std::numeric_limits<T>::is_signed
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|| std::numeric_limits<U>::is_signed,
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std::intmax_t,
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std::uintmax_t
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>::type;
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// section 4.13 integer conversion rank
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template<class T>
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using rank =
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typename boost::mpl::if_c<
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sizeof(char) == sizeof(T),
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std::integral_constant<int, 1>,
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typename boost::mpl::if_c<
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sizeof(short) == sizeof(T),
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std::integral_constant<int, 2>,
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typename boost::mpl::if_c<
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sizeof(int) == sizeof(T),
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std::integral_constant<int, 3>,
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typename boost::mpl::if_c<
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sizeof(long) == sizeof(T),
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std::integral_constant<int, 4>,
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typename boost::mpl::if_c<
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sizeof(long long) == sizeof(T),
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std::integral_constant<int, 5>,
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void
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>::type >::type >::type >::type >::type;
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// note presumption that T & U don't have he same sign
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// if that's not true, these won't work
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template<class T, class U>
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using select_signed = typename boost::mpl::if_c<
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std::numeric_limits<T>::is_signed,
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T,
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U
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>::type;
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template<class T, class U>
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using select_unsigned = typename boost::mpl::if_c<
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std::numeric_limits<T>::is_signed,
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U,
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T
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>::type;
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template<class T, class U>
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using calculate_max_t =
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typename boost::mpl::if_c<
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// clause 1 - if both operands have the same sign
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std::numeric_limits<T>::is_signed
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== std::numeric_limits<U>::is_signed,
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// use that sign
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typename boost::mpl::if_c<
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std::numeric_limits<T>::is_signed,
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std::intmax_t,
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std::uintmax_t
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>::type,
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// clause 2 - otherwise if the rank of he unsigned type exceeds
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// the rank of the of the maximum signed type
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typename boost::mpl::if_c<
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(rank< select_unsigned<T, U>>::value
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> rank< std::intmax_t >::value),
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// use unsigned type
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std::uintmax_t,
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// clause 3 - otherwise if the type of the signed integer type can
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// represent all the values of the unsigned type
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typename boost::mpl::if_c<
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std::numeric_limits< std::intmax_t >::digits >=
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std::numeric_limits< select_unsigned<T, U> >::digits,
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// use signed type
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std::intmax_t,
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// clause 4 - otherwise use unsigned version of the signed type
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std::uintmax_t
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>::type >::type >::type;
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template<typename T, T Min, T Max, class P, class E>
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struct defer_signed_lazily {
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using type = boost::numeric::safe_signed_range<Min, Max, P, E>;
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};
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template<typename T, T Min, T Max, class P, class E>
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struct defer_unsigned_lazily {
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using type = boost::numeric::safe_unsigned_range<Min, Max, P, E>;
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};
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template<typename T, T Min, T Max, class P, class E>
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using safe_range =
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typename boost::mpl::if_<
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std::is_signed<T>,
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defer_signed_lazily<T, Min, Max, P, E>,
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defer_unsigned_lazily<T, Min, Max, P, E>
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>::type;
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template<typename T, typename U, typename P, typename E>
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struct addition_result {
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typedef typename base_type<T>::type base_type_t;
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typedef typename base_type<U>::type base_type_u;
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SAFE_NUMERIC_CONSTEXPR static const interval<base_type_t> t = {
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base_value(std::numeric_limits<T>::min()),
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base_value(std::numeric_limits<T>::max())
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};
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SAFE_NUMERIC_CONSTEXPR static const interval<base_type_u> u = {
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base_value(std::numeric_limits<U>::min()),
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base_value(std::numeric_limits<U>::max())
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};
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typedef calculate_max_t<T, U> max_t;
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SAFE_NUMERIC_CONSTEXPR static const interval< max_t> r
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= operator+<max_t>(t, u);
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SAFE_NUMERIC_CONSTEXPR static const max_t newmin = r.l.is_valid() ?
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static_cast<max_t>(r.l)
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:
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std::numeric_limits<max_t>::min()
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;
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SAFE_NUMERIC_CONSTEXPR static const max_t newmax = r.u.is_valid() ?
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static_cast<max_t>(r.u)
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:
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std::numeric_limits<max_t>::max()
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;
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//typedef typename print<max_t>::type p_max_t;
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//typedef typename print<std::integral_constant<max_t, newmin>>::type p_newmin;
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//typedef typename print<std::integral_constant<max_t, newmax>>::type p_newmax;
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static_assert(
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newmin < newmax,
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"new minimumum must be less than new maximum"
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);
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static_assert(
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std::numeric_limits<max_t>::min() >= 0 || std::is_signed<max_t>::value,
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"newmin < 0 and unsigned can't happen"
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);
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typedef typename safe_range<
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max_t,
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newmin,
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newmax,
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P,
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E
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>::type type;
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/*
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typedef typename print<
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typename safe_range<
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max_t,
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newmin,
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newmax,
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P,
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E
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>::type
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>::type p_safe_range;
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*/
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};
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template<typename T, typename U, typename P, typename E>
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struct subtraction_result {
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typedef typename base_type<T>::type base_type_t;
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typedef typename base_type<U>::type base_type_u;
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SAFE_NUMERIC_CONSTEXPR static const interval<base_type_t> t = {
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base_value(std::numeric_limits<T>::min()),
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base_value(std::numeric_limits<T>::max())
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};
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SAFE_NUMERIC_CONSTEXPR static const interval<base_type_u> u = {
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base_value(std::numeric_limits<U>::min()),
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base_value(std::numeric_limits<U>::max())
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};
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typedef calculate_max_t<T, U> max_t;
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SAFE_NUMERIC_CONSTEXPR static const interval< max_t> r
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= operator-<max_t>(t, u);
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SAFE_NUMERIC_CONSTEXPR static const max_t newmin = r.l.is_valid() ?
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static_cast<max_t>(r.l)
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:
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std::numeric_limits<max_t>::min()
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;
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SAFE_NUMERIC_CONSTEXPR static const max_t newmax = r.u.is_valid() ?
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static_cast<max_t>(r.u)
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:
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std::numeric_limits<max_t>::max()
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;
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// typedef typename print<max_t>::type p_max_t;
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// typedef typename print<std::integral_constant<max_t, newmin>>::type p_newmin;
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// typedef typename print<std::integral_constant<max_t, newmax>>::type p_newmax;
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static_assert(
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newmin < newmax,
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"new minimumum must be less than new maximum"
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);
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static_assert(
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std::numeric_limits<max_t>::min() >= 0 || std::is_signed<max_t>::value,
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"newmin < 0 and unsigned can't happen"
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);
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typedef typename safe_range<
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max_t,
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newmin,
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newmax,
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P,
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E
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>::type type;
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};
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template<typename T, typename U, typename P, typename E>
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struct multiplication_result {
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typedef typename base_type<T>::type base_type_t;
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typedef typename base_type<U>::type base_type_u;
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SAFE_NUMERIC_CONSTEXPR static const interval<base_type_t> t = {
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base_value(std::numeric_limits<T>::min()),
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base_value(std::numeric_limits<T>::max())
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};
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SAFE_NUMERIC_CONSTEXPR static const interval<base_type_u> u = {
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base_value(std::numeric_limits<U>::min()),
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base_value(std::numeric_limits<U>::max())
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};
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typedef calculate_max_t<T, U> max_t;
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SAFE_NUMERIC_CONSTEXPR static const interval< max_t> r
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= operator*<max_t>(t, u);
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SAFE_NUMERIC_CONSTEXPR static const max_t newmin = r.l.is_valid() ?
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static_cast<max_t>(r.l)
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:
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std::numeric_limits<max_t>::min()
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;
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SAFE_NUMERIC_CONSTEXPR static const max_t newmax = r.u.is_valid() ?
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static_cast<max_t>(r.u)
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:
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std::numeric_limits<max_t>::max()
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;
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// typedef typename print<max_t>::type p_max_t;
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// typedef typename print<std::integral_constant<max_t, newmin>>::type p_newmin;
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// typedef typename print<std::integral_constant<max_t, newmax>>::type p_newmax;
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static_assert(
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newmin < newmax,
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"new minimumum must be less than new maximum"
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);
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static_assert(
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std::numeric_limits<max_t>::min() >= 0 || std::is_signed<max_t>::value,
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"newmin < 0 and unsigned can't happen"
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);
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typedef typename safe_range<
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max_t,
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newmin,
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newmax,
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P,
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E
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>::type type;
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};
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template<typename T, typename U, typename P, typename E>
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struct division_result {
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typedef typename base_type<T>::type t_base_type;
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typedef typename base_type<U>::type u_base_type;
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SAFE_NUMERIC_CONSTEXPR static const interval<t_base_type> t = {
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base_value(std::numeric_limits<T>::min()),
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base_value(std::numeric_limits<T>::max())
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};
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SAFE_NUMERIC_CONSTEXPR static const interval<u_base_type> u = {
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base_value(std::numeric_limits<U>::min()),
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base_value(std::numeric_limits<U>::max())
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};
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typedef decltype(t_base_type() / u_base_type()) r_base_type;
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SAFE_NUMERIC_CONSTEXPR static const interval<r_base_type> r
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= operator/<r_base_type>(t, u);
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typedef safe_base<r_base_type, r.l, r.u, P, E> type;
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};
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template<typename T, typename U, typename P, typename E>
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struct modulus_result {
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typedef typename base_type<T>::type t_base_type;
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typedef typename base_type<U>::type u_base_type;
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SAFE_NUMERIC_CONSTEXPR static const interval<t_base_type> t = {
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base_value(std::numeric_limits<T>::min()),
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base_value(std::numeric_limits<T>::max())
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};
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SAFE_NUMERIC_CONSTEXPR static const interval<u_base_type> u = {
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base_value(std::numeric_limits<U>::min()),
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base_value(std::numeric_limits<U>::max())
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};
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typedef decltype(t_base_type() % u_base_type()) r_base_type;
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SAFE_NUMERIC_CONSTEXPR static const interval<r_base_type> r
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= operator%<r_base_type>(t, u);
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typedef safe_base<r_base_type, r.l, r.u, P, E> type;
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};
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template<typename T, typename U, typename P, typename E>
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struct left_shift_result {
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typedef typename base_type<T>::type t_base_type;
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typedef typename base_type<U>::type u_base_type;
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SAFE_NUMERIC_CONSTEXPR static const interval<t_base_type> t = {
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base_value(std::numeric_limits<T>::min()),
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base_value(std::numeric_limits<T>::max())
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};
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SAFE_NUMERIC_CONSTEXPR static const interval<u_base_type> u = {
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base_value(std::numeric_limits<U>::min()),
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base_value(std::numeric_limits<U>::max())
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};
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typedef decltype(t_base_type() << u_base_type()) r_base_type;
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SAFE_NUMERIC_CONSTEXPR static const interval<r_base_type> r
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= operator<<<r_base_type>(t, u);
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typedef safe_base<r_base_type, r.l, r.u, P, E> type;
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};
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template<typename T, typename U, typename P, typename E>
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struct right_shift_result {
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typedef typename base_type<T>::type t_base_type;
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typedef typename base_type<U>::type u_base_type;
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SAFE_NUMERIC_CONSTEXPR static const interval<t_base_type> t = {
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base_value(std::numeric_limits<T>::min()),
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base_value(std::numeric_limits<T>::max())
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};
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SAFE_NUMERIC_CONSTEXPR static const interval<u_base_type> u = {
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base_value(std::numeric_limits<U>::min()),
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base_value(std::numeric_limits<U>::max())
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};
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typedef decltype(t_base_type() >> u_base_type()) r_base_type;
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SAFE_NUMERIC_CONSTEXPR static const interval<r_base_type> r
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= operator>><r_base_type>(t, u);
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typedef safe_base<r_base_type, r.l, r.u, P, E> type;
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};
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};
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} // numeric
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} // boost
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#endif // BOOST_NUMERIC_AUTOMATIC_HPP
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