mirror of
https://github.com/yuzu-emu/ext-boost.git
synced 2024-12-23 08:15:32 +00:00
198 lines
6.6 KiB
C++
198 lines
6.6 KiB
C++
|
#ifndef BOOST_NUMERIC_CPP_HPP
|
||
|
#define BOOST_NUMERIC_CPP_HPP
|
||
|
|
||
|
// 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, conditional
|
||
|
#include <limits>
|
||
|
#include <boost/integer.hpp> // integer type selection
|
||
|
|
||
|
#include "safe_common.hpp"
|
||
|
#include "checked_result.hpp"
|
||
|
|
||
|
namespace boost {
|
||
|
namespace safe_numerics {
|
||
|
|
||
|
// 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 {
|
||
|
public:
|
||
|
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;
|
||
|
|
||
|
template<class T>
|
||
|
using rank =
|
||
|
typename std::conditional<
|
||
|
std::is_same<local_char_type, typename std::make_signed<T>::type>::value,
|
||
|
std::integral_constant<int, 1>,
|
||
|
typename std::conditional<
|
||
|
std::is_same<local_short_type, typename std::make_signed<T>::type>::value,
|
||
|
std::integral_constant<int, 2>,
|
||
|
typename std::conditional<
|
||
|
std::is_same<local_int_type, typename std::make_signed<T>::type>::value,
|
||
|
std::integral_constant<int, 3>,
|
||
|
typename std::conditional<
|
||
|
std::is_same<local_long_type, typename std::make_signed<T>::type>::value,
|
||
|
std::integral_constant<int, 4>,
|
||
|
typename std::conditional<
|
||
|
std::is_same<local_long_long_type, typename std::make_signed<T>::type>::value,
|
||
|
std::integral_constant<int, 5>,
|
||
|
std::integral_constant<int, 6> // catch all - never promote integral
|
||
|
>::type >::type >::type >::type >::type;
|
||
|
|
||
|
// section 4.5 integral promotions
|
||
|
|
||
|
// convert smaller of two types to the size of the larger
|
||
|
template<class T, class U>
|
||
|
using higher_ranked_type = typename std::conditional<
|
||
|
(rank<T>::value < rank<U>::value),
|
||
|
U,
|
||
|
T
|
||
|
>::type;
|
||
|
|
||
|
template<class T, class U>
|
||
|
using copy_sign = typename std::conditional<
|
||
|
std::is_signed<U>::value,
|
||
|
typename std::make_signed<T>::type,
|
||
|
typename std::make_unsigned<T>::type
|
||
|
>::type;
|
||
|
|
||
|
template<class T>
|
||
|
using integral_promotion = copy_sign<
|
||
|
higher_ranked_type<local_int_type, T>,
|
||
|
T
|
||
|
>;
|
||
|
|
||
|
// 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 std::conditional<
|
||
|
std::numeric_limits<T>::is_signed,
|
||
|
T,
|
||
|
U
|
||
|
>::type;
|
||
|
|
||
|
template<class T, class U>
|
||
|
using select_unsigned = typename std::conditional<
|
||
|
std::numeric_limits<T>::is_signed,
|
||
|
U,
|
||
|
T
|
||
|
>::type;
|
||
|
|
||
|
// section 5 clause 11 - usual arithmetic conversions
|
||
|
template<typename T, typename U>
|
||
|
using usual_arithmetic_conversions =
|
||
|
// clause 0 - if both operands have the same type
|
||
|
typename std::conditional<
|
||
|
std::is_same<T, U>::value,
|
||
|
// no further conversion is needed
|
||
|
T,
|
||
|
// clause 1 - otherwise if both operands have the same sign
|
||
|
typename std::conditional<
|
||
|
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 std::conditional<
|
||
|
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 std::conditional<
|
||
|
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
|
||
|
std::make_signed< select_signed<T, U>>
|
||
|
>::type >::type >::type
|
||
|
>;
|
||
|
|
||
|
template<typename T, typename U>
|
||
|
using result_type = typename usual_arithmetic_conversions<
|
||
|
integral_promotion<typename base_type<T>::type>,
|
||
|
integral_promotion<typename base_type<U>::type>
|
||
|
>::type;
|
||
|
public:
|
||
|
template<typename T, typename U>
|
||
|
struct addition_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
template<typename T, typename U>
|
||
|
struct subtraction_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
template<typename T, typename U>
|
||
|
struct multiplication_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
template<typename T, typename U>
|
||
|
struct division_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
template<typename T, typename U>
|
||
|
struct modulus_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
// note: comparison_result (<, >, ...) is special.
|
||
|
// The return value is always a bool. The type returned here is
|
||
|
// the intermediate type applied to make the values comparable.
|
||
|
template<typename T, typename U>
|
||
|
struct comparison_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
template<typename T, typename U>
|
||
|
struct left_shift_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
template<typename T, typename U>
|
||
|
struct right_shift_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
template<typename T, typename U>
|
||
|
struct bitwise_and_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
template<typename T, typename U>
|
||
|
struct bitwise_or_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
template<typename T, typename U>
|
||
|
struct bitwise_xor_result {
|
||
|
using type = result_type<T, U>;
|
||
|
};
|
||
|
};
|
||
|
|
||
|
} // safe_numerics
|
||
|
} // boost
|
||
|
|
||
|
#endif // BOOST_NUMERIC_cpp_HPP
|