mirror of
https://github.com/boostorg/safe_numerics.git
synced 2026-02-02 21:12:17 +00:00
214 lines
7.3 KiB
C++
Executable File
214 lines
7.3 KiB
C++
Executable File
#ifndef BOOST_NUMERIC_CPP_HPP
|
|
#define BOOST_NUMERIC_CPP_HPP
|
|
|
|
// MS compatible compilers support #pragma once
|
|
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
|
|
# pragma once
|
|
#endif
|
|
|
|
// Copyright (c) 2012 Robert Ramey
|
|
//
|
|
// 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)
|
|
|
|
// policy which creates results types equal to that of C++ promotions.
|
|
// Using the policy will permit the program to build and run in release
|
|
// mode which is identical to that in debug mode except for the fact
|
|
// that errors aren't trapped.
|
|
|
|
#include <type_traits> // integral constant, remove_cv
|
|
#include <limits>
|
|
#include <boost/integer.hpp> // integer type selection
|
|
#include <boost/mpl/if.hpp>
|
|
|
|
#include "safe_common.hpp"
|
|
#include "checked.hpp"
|
|
|
|
// forward declaration - safe type
|
|
template<
|
|
class Stored,
|
|
Stored Min,
|
|
Stored Max,
|
|
class P, // promotion polic
|
|
class E // exception policy
|
|
>
|
|
class safe_base;
|
|
|
|
namespace boost {
|
|
namespace numeric {
|
|
|
|
// in C++ the following rules govern integer arithmetic
|
|
|
|
// This policy is use to emulate another compiler/machine architecture
|
|
// For example, a Z80 has 8 bit char, 16 bit short, 16 bit int, 32 bit long. So one
|
|
// would use cpp<8, 16, 16, 32, 32> to test programs destined to run on a Z80
|
|
|
|
// Follow section 5 of the standard.
|
|
template<
|
|
int CharBits,
|
|
int ShortBits,
|
|
int IntBits,
|
|
int LongBits,
|
|
int LongLongBits
|
|
>
|
|
struct cpp {
|
|
template<typename T>
|
|
using normalize = typename std::make_signed<typename std::remove_cv<T>::type>::type;
|
|
|
|
using local_char_type = typename boost::int_t<CharBits>::exact;
|
|
using local_short_type = typename boost::int_t<ShortBits>::exact;
|
|
using local_int_type = typename boost::int_t<IntBits>::exact;
|
|
using local_long_type = typename boost::int_t<LongBits>::exact;
|
|
using local_long_long_type = typename boost::int_t<LongLongBits>::exact;
|
|
|
|
// section 4.13 integer conversion rank
|
|
template<class T>
|
|
using rank =
|
|
typename boost::mpl::if_<
|
|
std::is_same<bool, normalize<T> >,
|
|
std::integral_constant<int, 0>,
|
|
typename boost::mpl::if_c<
|
|
sizeof(local_char_type) == sizeof(T),
|
|
std::integral_constant<int, 1>,
|
|
typename boost::mpl::if_c<
|
|
sizeof(local_short_type) == sizeof(T),
|
|
std::integral_constant<int, 2>,
|
|
typename boost::mpl::if_c<
|
|
sizeof(local_int_type) == sizeof(T),
|
|
std::integral_constant<int, 3>,
|
|
typename boost::mpl::if_c<
|
|
sizeof(local_long_type) == sizeof(T),
|
|
std::integral_constant<int, 4>,
|
|
typename boost::mpl::if_c<
|
|
sizeof(local_long_long_type) == sizeof(T),
|
|
std::integral_constant<int, 5>,
|
|
void
|
|
>::type >::type >::type >::type >::type >::type;
|
|
|
|
// section 4.5 integral promotions
|
|
template<class T>
|
|
using integral_promotion = typename boost::mpl::if_c<
|
|
rank<T>::value < rank<local_int_type>::value,
|
|
local_int_type,
|
|
T
|
|
>::type;
|
|
|
|
// convert smaller of two types to the size of the larger
|
|
template<class T, class U>
|
|
using higher_ranked_type = typename boost::mpl::if_c<
|
|
(rank<T>::value < rank<U>::value),
|
|
U,
|
|
T
|
|
>::type;
|
|
|
|
// note presumption that T & U don't have he same sign
|
|
// if that's not true, these won't work
|
|
template<class T, class U>
|
|
using select_signed = typename boost::mpl::if_c<
|
|
std::numeric_limits<T>::is_signed,
|
|
T,
|
|
U
|
|
>::type;
|
|
|
|
template<class T, class U>
|
|
using select_unsigned = typename boost::mpl::if_c<
|
|
std::numeric_limits<T>::is_signed,
|
|
U,
|
|
T
|
|
>::type;
|
|
|
|
// section 5 - usual arithmetic conversions
|
|
template<typename T, typename U>
|
|
using usual_arithmetic_conversions =
|
|
// clause 0 - if both operands have the same type
|
|
typename boost::mpl::if_c<
|
|
std::is_same<T, U>::value,
|
|
// no further conversion is needed
|
|
T,
|
|
// clause 1 - otherwise if both operands have the same sign
|
|
typename boost::mpl::if_c<
|
|
std::numeric_limits<T>::is_signed
|
|
== std::numeric_limits<U>::is_signed,
|
|
// convert to the higher ranked type
|
|
higher_ranked_type<T, U>,
|
|
// clause 2 - otherwise if the rank of he unsigned type exceeds
|
|
// the rank of the of the signed type
|
|
typename boost::mpl::if_c<
|
|
rank< select_unsigned<T, U>>::value
|
|
>= rank< select_signed<T, U>>::value,
|
|
// use unsigned type
|
|
select_unsigned<T, U>,
|
|
// clause 3 - otherwise if the type of the signed integer type can
|
|
// represent all the values of the unsigned type
|
|
typename boost::mpl::if_c<
|
|
std::numeric_limits< select_signed<T, U> >::digits >=
|
|
std::numeric_limits< select_unsigned<T, U> >::digits,
|
|
// use signed type
|
|
select_signed<T, U>,
|
|
// clause 4 - otherwise use unsigned version of the signed type
|
|
typename std::make_signed< select_signed<T, U> >
|
|
>::type >::type >::type >::type;
|
|
|
|
template<typename T, typename U, typename P, typename E>
|
|
struct safe_type_promotion {
|
|
using base_type_t = typename base_type<T>::type;
|
|
using base_type_u = typename base_type<U>::type;
|
|
using result_base_type = usual_arithmetic_conversions<
|
|
integral_promotion<base_type_t>,
|
|
integral_promotion<base_type_u>
|
|
>;
|
|
using type = safe_base<
|
|
result_base_type,
|
|
std::numeric_limits<result_base_type>::min(),
|
|
std::numeric_limits<result_base_type>::max(),
|
|
P,
|
|
E
|
|
>;
|
|
};
|
|
|
|
template<typename T, typename U, typename P, typename E>
|
|
struct addition_result {
|
|
using type = typename safe_type_promotion<T, U, P, E>::type;
|
|
};
|
|
template<typename T, typename U, typename P, typename E>
|
|
struct subtraction_result {
|
|
typedef typename safe_type_promotion<T, U, P, E>::type type;
|
|
};
|
|
template<typename T, typename U, typename P, typename E>
|
|
struct multiplication_result {
|
|
typedef typename safe_type_promotion<T, U, P, E>::type type;
|
|
};
|
|
template<typename T, typename U, typename P, typename E>
|
|
struct division_result {
|
|
typedef typename safe_type_promotion<T, U, P, E>::type type;
|
|
};
|
|
// forward to correct divide implementation
|
|
template<class R, class T, class U>
|
|
checked_result<R>
|
|
static constexpr divide(
|
|
const T & t,
|
|
const U & u
|
|
){
|
|
return checked::divide<R>(t, u);
|
|
}
|
|
|
|
template<typename T, typename U, typename P, typename E>
|
|
struct modulus_result {
|
|
typedef typename safe_type_promotion<T, U, P, E>::type type;
|
|
};
|
|
template<typename T, typename U, typename P, typename E>
|
|
struct left_shift_result {
|
|
typedef typename safe_type_promotion<T, U, P, E>::type type;
|
|
};
|
|
template<typename T, typename U, typename P, typename E>
|
|
struct right_shift_result {
|
|
typedef typename safe_type_promotion<T, U, P, E>::type type;
|
|
};
|
|
};
|
|
|
|
} // numeric
|
|
} // boost
|
|
|
|
#endif // BOOST_NUMERIC_cpp_HPP
|