Files
safe_numerics/include/safe_base_operations.hpp
Robert Ramey 4a8c7c31d8 passes all tests.
version 2.0 of exception policy design.
2017-05-30 20:46:45 -07:00

1651 lines
51 KiB
C++

#ifndef BOOST_NUMERIC_SAFE_BASE_OPERATIONS_HPP
#define BOOST_NUMERIC_SAFE_BASE_OPERATIONS_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)
#include <limits>
#include <type_traits> // is_base_of, is_same, enable_if
#include <algorithm> // max
#include <cassert>
#include <boost/config.hpp>
#include <boost/mpl/if.hpp>
#include <boost/mpl/identity.hpp>
#include <boost/utility/enable_if.hpp> // lazy_enable_if
#include <boost/integer.hpp>
#include "safe_base.hpp"
#include "safe_literal.hpp"
#include "safe_compare.hpp"
#include "checked_result.hpp"
#include "interval.hpp"
#include "checked.hpp"
namespace boost {
namespace numeric {
/////////////////////////////////////////////////////////////////
// validation
template<typename R, typename E>
struct validate_detail {
struct exception_possible {
template<typename T>
constexpr static R return_value(
const T & t,
const interval<R> & r_interval
){
// INT08-C
const checked_result<R> r = r_interval.includes(t) ?
checked::cast<R>(t)
:
checked_result<R>(
safe_numerics_error::domain_error,
"Value out of range for this safe type"
)
;
dispatch<E>(r);
return r;
}
};
struct exception_not_possible {
template<typename T>
constexpr static R return_value(
const T & t,
const interval<R> & this_interval
){
return static_cast<R>(t);
}
};
};
template<class Stored, Stored Min, Stored Max, class P, class E>
template<class T>
constexpr Stored safe_base<Stored, Min, Max, P, E>::
validated_cast(const T & t) const {
using t_base_type = typename base_type<T>::type;
constexpr const interval<t_base_type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr const interval<Stored> this_interval(Min, Max);
// if static values don't overlap, the program can never function
static_assert(
indeterminate(t_interval < this_interval),
"safe type cannot be constructed with this type"
);
return boost::mpl::if_c<
this_interval.includes(t_interval),
typename validate_detail<Stored, E>::exception_not_possible,
typename validate_detail<Stored, E>::exception_possible
>::type::template return_value(base_value(t), this_interval);
}
template<class Stored, Stored Min, Stored Max, class P, class E>
template<typename T, T N, class P1, class E1>
constexpr Stored safe_base<Stored, Min, Max, P, E>::
validated_cast(const safe_literal_impl<T, N, P1, E1> &) const {
constexpr const interval<Stored> this_interval{};
// if static values don't overlap, the program can never function
static_assert(
this_interval.includes(N),
"safe type cannot be constructed from this value"
);
return static_cast<Stored>(N);
}
/////////////////////////////////////////////////////////////////
// construction and assignment operators
template<class Stored, Stored Min, Stored Max, class P, class E>
constexpr safe_base<Stored, Min, Max, P, E>::
safe_base(const Stored & rhs, std::false_type) :
m_t(rhs)
{}
// construction from some arbitrary type T
template<class Stored, Stored Min, Stored Max, class P, class E>
template<class T>
constexpr safe_base<Stored, Min, Max, P, E>::
safe_base(const T & rhs) :
m_t(validated_cast(rhs))
{}
// assignment from some type T
template<class Stored, Stored Min, Stored Max, class P, class E>
template<class T, T MinT, T MaxT, class PT, class ET>
constexpr safe_base<Stored, Min, Max, P, E> &
safe_base<Stored, Min, Max, P, E>::
operator=(const safe_base<T, MinT, MaxT, PT, ET> & rhs){
m_t = validated_cast(rhs);
return *this;
}
/////////////////////////////////////////////////////////////////
// casting operators
template< class Stored, Stored Min, Stored Max, class P, class E>
template<
class R,
typename std::enable_if<
!boost::numeric::is_safe<R>::value,
int
>::type
>
constexpr safe_base<Stored, Min, Max, P, E>::
operator R () const {
constexpr const interval<R> r_interval;
constexpr const interval<Stored> this_interval(Min, Max);
// if static values don't overlap, the program can never function
static_assert(
indeterminate(r_interval < this_interval),
"safe type cannot be constructed with this type"
);
return boost::mpl::if_c<
r_interval.includes(this_interval),
typename validate_detail<R, E>::exception_not_possible,
typename validate_detail<R, E>::exception_possible
>::type::template return_value(m_t, r_interval);
}
template< class Stored, Stored Min, Stored Max, class P, class E>
constexpr safe_base<Stored, Min, Max, P, E>::
operator Stored () const {
return m_t;
}
/////////////////////////////////////////////////////////////////
// binary operators
template<class T, class U>
struct common_exception_policy {
static_assert(is_safe<T>::value || is_safe<U>::value,
"at least one type must be a safe type"
);
using t_exception_policy = typename get_exception_policy<T>::type;
using u_exception_policy = typename get_exception_policy<U>::type;
static_assert(
std::is_same<t_exception_policy, u_exception_policy>::value
|| std::is_same<t_exception_policy, void>::value
|| std::is_same<void, u_exception_policy>::value,
"if the exception policies are different, one must be void!"
);
static_assert(
! (std::is_same<t_exception_policy, void>::value
&& std::is_same<void, u_exception_policy>::value),
"at least one exception policy must not be void"
);
using type =
typename boost::mpl::if_c<
!std::is_same<void, u_exception_policy>::value,
u_exception_policy,
typename boost::mpl::if_c<
!std::is_same<void, t_exception_policy>::value,
t_exception_policy,
//
void
>::type >::type;
static_assert(
!std::is_same<void, type>::value,
"exception_policy is void"
);
};
template<class T, class U>
struct common_promotion_policy {
static_assert(is_safe<T>::value || is_safe<U>::value,
"at least one type must be a safe type"
);
using t_promotion_policy = typename get_promotion_policy<T>::type;
using u_promotion_policy = typename get_promotion_policy<U>::type;
static_assert(
std::is_same<t_promotion_policy, u_promotion_policy>::value
||std::is_same<t_promotion_policy, void>::value
||std::is_same<void, u_promotion_policy>::value,
"if the promotion policies are different, one must be void!"
);
static_assert(
! (std::is_same<t_promotion_policy, void>::value
&& std::is_same<void, u_promotion_policy>::value),
"at least one promotion policy must not be void"
);
using type =
typename boost::mpl::if_c<
! std::is_same<void, u_promotion_policy>::value,
u_promotion_policy,
typename boost::mpl::if_c<
! std::is_same<void, t_promotion_policy>::value,
t_promotion_policy,
//
void
>::type >::type;
static_assert(
! std::is_same<void, type>::value,
"promotion_policy is void"
);
};
// Note: the following global operators will be found via
// argument dependent lookup.
/////////////////////////////////////////////////////////////////
// addition
template<class T, class U>
struct addition_result {
private:
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type =
typename promotion_policy::template addition_result<T,U>::type;
constexpr static const interval<typename base_type<T>::type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<typename base_type<U>::type> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
// when we add the temporary intervals above, we'll get a new interval
// with the correct range for the sum !
constexpr static const interval<checked_result<result_base_type>> r_interval =
add<result_base_type>(t_interval, u_interval);
constexpr static const bool exception_possible() {
return r_interval.l.exception() || r_interval.u.exception();
}
using exception_policy = typename common_exception_policy<T, U>::type;
struct safe_type {
using type = safe_base<
result_base_type,
r_interval.l.exception()
? std::numeric_limits<result_base_type>::min()
: static_cast<result_base_type>(r_interval.l),
r_interval.u.exception()
? std::numeric_limits<result_base_type>::max()
: static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static const type make(const result_base_type & t){
return type(t, std::false_type());
}
};
struct unsafe_type {
using type = result_base_type;
constexpr static const type make(const result_base_type & t){
return t;
}
};
using type_helper = typename boost::mpl::if_c<
std::numeric_limits<result_base_type>::is_integer,
safe_type,
unsafe_type
>::type;
constexpr static result_base_type
add(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
+ static_cast<result_base_type>(base_value(u))
;
}
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
static_assert(! exception_possible(), "no runtime check");
return add(t,u);
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
static_assert(exception_possible(), "implement runtime check");
checked_result<result_base_type> r = checked::add<result_base_type>(
base_value(t),
base_value(u)
);
if(!r.exception())
return static_cast<result_base_type>(r);
// handle error condition
dispatch<exception_policy>(r);
// if we get here, the error has been ignored
// just get the result the old fashioned way
return add(t, u);
}
public:
using type = typename type_helper::type;
constexpr static type return_value(const T & t, const U & u){
return type_helper::make( return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
));
}
};
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
typename addition_result<T, U>::type
>::type
constexpr operator+(const T & t, const U & u){
return addition_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator+=(T & t, const U & u){
t = static_cast<T>(t + u);
return t;
}
/////////////////////////////////////////////////////////////////
// subtraction
template<class T, class U>
struct subtraction_result {
private:
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type =
typename promotion_policy::template subtraction_result<T, U>::type;
constexpr static const interval<typename base_type<T>::type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<typename base_type<U>::type> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
// when we subtract the temporary intervals above, we'll get a new interval
// with the correct range for the difference !
constexpr static const interval<checked_result<result_base_type>> r_interval =
subtract<result_base_type>(t_interval, u_interval);
constexpr static const bool exception_possible() {
return r_interval.l.exception() || r_interval.u.exception();
}
using exception_policy = typename common_exception_policy<T, U>::type;
struct safe_type {
using type = safe_base<
result_base_type,
r_interval.l.exception()
? std::numeric_limits<result_base_type>::min()
: static_cast<result_base_type>(r_interval.l),
r_interval.u.exception()
? std::numeric_limits<result_base_type>::max()
: static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static const type make(const result_base_type & t){
return type(t, std::false_type());
}
};
struct unsafe_type {
using type = result_base_type;
constexpr static const type make(const result_base_type & t){
return t;
}
};
using type_helper = typename boost::mpl::if_c<
std::numeric_limits<result_base_type>::is_integer,
safe_type,
unsafe_type
>::type;
constexpr static result_base_type
subtract(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
- static_cast<result_base_type>(base_value(u))
;
}
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
static_assert(! exception_possible(), "no runtime check");
return subtract(t, u);
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
static_assert(exception_possible(), "implement runtime check");
checked_result<result_base_type> r = checked::subtract<result_base_type>(
base_value(t),
base_value(u)
);
if(!r.exception())
return static_cast<result_base_type>(r);
dispatch<exception_policy>(r);
return subtract(t, u);
}
public:
using type = typename type_helper::type;
constexpr static type return_value(const T & t, const U & u){
return type_helper::make( return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
));
}
};
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
typename subtraction_result<T, U>::type
>::type
constexpr operator-(const T & t, const U & u){
return subtraction_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator-=(T & t, const U & u){
t = static_cast<T>(t - u);
return t;
}
/////////////////////////////////////////////////////////////////
// multiplication
template<class T, class U>
struct multiplication_result {
private:
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type =
typename promotion_policy::template multiplication_result<T, U>::type;
using exception_policy = typename common_exception_policy<T, U>::type;
struct safe_type {
constexpr static const interval<typename base_type<T>::type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<typename base_type<U>::type> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
constexpr static const interval<checked_result<result_base_type>> r_interval =
multiply<result_base_type>(t_interval, u_interval);
constexpr static const bool exception_possible() {
return r_interval.l.exception() || r_interval.u.exception();
}
using type = safe_base<
result_base_type,
r_interval.l.exception()
? std::numeric_limits<result_base_type>::min()
: static_cast<result_base_type>(r_interval.l),
r_interval.u.exception()
? std::numeric_limits<result_base_type>::max()
: static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static const type make(const result_base_type & t){
return type(t, std::false_type());
}
};
struct unsafe_type {
using type = result_base_type;
constexpr static const type make(const result_base_type & t){
return t;
}
constexpr static bool exception_possible() {
return false;
}
};
using type_helper = typename boost::mpl::if_c<
std::numeric_limits<result_base_type>::is_integer,
safe_type,
unsafe_type
>::type;
constexpr static bool exception_possible() {
return type_helper::exception_possible();
}
constexpr static result_base_type
multiply(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
* static_cast<result_base_type>(base_value(u))
;
}
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
static_assert(! exception_possible(), "no runtime check");
return multiply(t, u);
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
static_assert(exception_possible(), "implement runtime check");
checked_result<result_base_type> r = checked::multiply<result_base_type>(
base_value(t),
base_value(u)
);
if(!r.exception())
return static_cast<result_base_type>(r);
dispatch<exception_policy>(r);
return multiply(t, u);
}
public:
using type = typename type_helper::type;
constexpr static type return_value(const T & t, const U & u){
return type_helper::make( return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
));
}
};
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
typename multiplication_result<T, U>::type
>::type
constexpr operator*(const T & t, const U & u){
// argument dependent lookup should guarentee that we only get here
return multiplication_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator*=(T & t, const U & u){
t = static_cast<T>(t * u);
return t;
}
/////////////////////////////////////////////////////////////////
// division
// key idea here - result will never be larger than T
template<class T, class U>
struct division_result {
private:
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type = typename promotion_policy::template division_result<T, U>::type;
using t_base = typename base_type<T>::type;
using u_base = typename base_type<U>::type;
using exception_policy = typename common_exception_policy<T, U>::type;
struct safe_type {
constexpr static const interval<t_base> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<u_base> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
constexpr static const interval<checked_result<result_base_type>> r_interval
= divide<result_base_type>(t_interval, u_interval);
static_assert(! r_interval.l.exception(), "unexpected negative overflow");
static_assert(! r_interval.u.exception(), "unexpected positive overflow");
constexpr static const bool exception_possible() {
return
u_interval.includes(0)
||
(u_interval.includes(-1)
&& t_interval.includes(std::numeric_limits<T>::min())
)
;
}
using type = safe_base<
result_base_type,
static_cast<result_base_type>(r_interval.l),
static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static type make(const result_base_type & t){
return type(t, std::false_type());
}
};
struct unsafe_type {
using type = result_base_type;
constexpr static const type make(const result_base_type & t){
return t;
}
constexpr static bool exception_possible() {
return false;
}
};
using type_helper = typename boost::mpl::if_c<
std::numeric_limits<result_base_type>::is_integer,
safe_type,
unsafe_type
>::type;
constexpr static bool exception_possible() {
return type_helper::exception_possible();
}
constexpr static result_base_type
divide(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
/ static_cast<result_base_type>(base_value(u))
;
}
constexpr static int bits = std::min(
std::numeric_limits<std::uintmax_t>::digits,
std::max(std::initializer_list<int>{
std::numeric_limits<result_base_type>::digits,
std::numeric_limits<t_base>::digits,
std::numeric_limits<u_base>::digits
}) + (std::numeric_limits<result_base_type>::is_signed ? 1 : 0)
);
using temp_base = typename boost::mpl::if_c<
std::numeric_limits<result_base_type>::is_signed,
typename boost::int_t<bits>::least,
typename boost::uint_t<bits>::least
>::type;
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
return divide(t, u);
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
checked_result<temp_base> r = checked::divide<temp_base>(
base_value(t),
base_value(u)
);
if(!r.exception())
return static_cast<result_base_type>(r);
dispatch<exception_policy>(r);
return divide(t, u);
}
public:
using type = typename type_helper::type;
constexpr static type return_value(const T & t, const U & u){
return type_helper::make( return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
));
}
};
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
typename division_result<T, U>::type
>::type
constexpr operator/(const T & t, const U & u){
return division_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator/=(T & t, const U & u){
t = static_cast<T>(t / u);
return t;
}
/////////////////////////////////////////////////////////////////
// modulus
template<class T, class U>
struct modulus_result {
private:
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type = typename promotion_policy::template modulus_result<T, U>::type;
using exception_policy = typename common_exception_policy<T, U>::type;
struct safe_type {
constexpr static const interval<typename base_type<T>::type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<typename base_type<U>::type> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
constexpr static const interval<checked_result<result_base_type>> r_interval
= modulus<result_base_type>(t_interval, u_interval);
constexpr static bool exception_possible() {
return
// if over/under flow or domain error possible
(r_interval.l.exception() || r_interval.u.exception())
// if the denominator can contain zero
|| u_interval.includes(0)
;
}
using type = safe_base<
result_base_type,
r_interval.l.exception()
? std::numeric_limits<result_base_type>::min()
: static_cast<result_base_type>(r_interval.l),
r_interval.u.exception()
? std::numeric_limits<result_base_type>::max()
: static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static const type make(const result_base_type & t){
return type(t, std::false_type());
}
};
struct unsafe_type {
using type = result_base_type;
constexpr static const type make(const result_base_type & t){
return t;
}
constexpr static bool exception_possible() {
return false;
}
};
using type_helper = typename boost::mpl::if_c<
std::numeric_limits<result_base_type>::is_integer,
safe_type,
unsafe_type
>::type;
constexpr static bool exception_possible() {
return type_helper::exception_possible();
}
constexpr static result_base_type
modulus(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
% static_cast<result_base_type>(base_value(u))
;
}
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
static_assert(! exception_possible(), "no runtime check");
return modulus(t, u);
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
static_assert(exception_possible(), "implement runtime check");
checked_result<result_base_type> r = checked::modulus<result_base_type>(
base_value(t),
base_value(u)
);
if(!r.exception())
return static_cast<result_base_type>(r);
dispatch<exception_policy>(r);
return static_cast<result_base_type>(r);
}
public:
using type = typename type_helper::type;
constexpr static type return_value(const T & t, const U & u){
return type_helper::make( return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
));
}
};
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
typename modulus_result<T, U>::type
>::type
constexpr operator%(const T & t, const U & u){
// see https://en.wikipedia.org/wiki/Modulo_operation
return modulus_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator%=(T & t, const U & u){
t = static_cast<T>(t % u);
return t;
}
/////////////////////////////////////////////////////////////////
// comparison
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
bool
>::type
constexpr operator<(const T & lhs, const U & rhs) {
// filter out case were overflow cannot occur
constexpr const interval<typename base_type<T>::type> t_interval(
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
);
constexpr const interval<typename base_type<U>::type> u_interval(
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
);
const boost::tribool x = t_interval < u_interval;
return
x ? true :
!x ? false:
safe_compare::less_than(base_value(lhs), base_value(rhs));
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
bool
>::type
constexpr operator>(const T & lhs, const U & rhs) {
return rhs < lhs;
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
bool
>::type
constexpr operator>=(const T & lhs, const U & rhs) {
return ! ( rhs < lhs );
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
bool
>::type
constexpr operator<=(const T & lhs, const U & rhs) {
return ! ( lhs > rhs );
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
bool
>::type
constexpr operator==(const T & lhs, const U & rhs) {
constexpr const interval<typename base_type<T>::type> t_interval(
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
);
constexpr const interval<typename base_type<T>::type> u_interval(
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
);
return
// if the ranges don't overlap
( t_interval < u_interval || t_interval > u_interval) ?
// values in those ranges can't be equal
false
:
// otherwise we have to check
safe_compare::equal(base_value(lhs), base_value(rhs));
;
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
bool
>::type
constexpr operator!=(const T & lhs, const U & rhs) {
return ! (lhs == rhs);
}
/////////////////////////////////////////////////////////////////
// shift operators
// left shift
template<class T, class U>
struct left_shift_result {
private:
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type =
typename promotion_policy::template left_shift_result<T, U>::type;
constexpr static const interval<typename base_type<T>::type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<typename base_type<U>::type> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
static_assert(t_interval.u >= 0, "negative values can't be shifted");
static_assert(u_interval.u >= 0, "shift count can't be negative");
static_assert(u_interval.l <= std::numeric_limits<T>::digits,
"shift count can't exceed argument size"
);
constexpr static const interval<checked_result<result_base_type>> r_interval {
left_shift<result_base_type>(t_interval, u_interval)
};
constexpr static const bool exception_possible() {
return r_interval.l.exception() || r_interval.u.exception();
}
using exception_policy = typename common_exception_policy<T, U>::type;
constexpr static result_base_type
left_shift(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
<< static_cast<result_base_type>(base_value(u))
;
}
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
static_assert(! exception_possible(), "no runtime check");
return left_shift(t, u);
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
static_assert(exception_possible(), "implement runtime check");
checked_result<result_base_type> r = checked::left_shift<result_base_type>(
base_value(t),
base_value(u)
);
if(!r.exception())
return static_cast<result_base_type>(r);
dispatch<exception_policy>(r);
return left_shift(t, u);
}
public:
using type = safe_base<
result_base_type,
r_interval.l.exception()
? std::numeric_limits<result_base_type>::min()
: static_cast<result_base_type>(r_interval.l),
r_interval.u.exception()
? std::numeric_limits<result_base_type>::max()
: static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static type return_value(const T & t, const U & u){
return return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
);
}
};
template<class T, class U>
typename boost::lazy_enable_if_c<
// handle safe<T> << int, int << safe<U>, safe<T> << safe<U>
// exclude std::ostream << ...
(! std::is_base_of<std::ios_base, T>::value)
&& (
boost::numeric::is_safe<T>::value
||boost::numeric::is_safe<U>::value
),
left_shift_result<T, U>
>::type
constexpr operator<<(const T & t, const U & u){
// INT13-CPP
// C++ standards document N4618 & 5.8.2
static_assert(
std::numeric_limits<T>::is_integer, "shifted value must be an integer"
);
static_assert(
std::numeric_limits<U>::is_integer, "shift amount must be an integer"
);
return left_shift_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator<<=(T & t, const U & u){
t = static_cast<T>(t << u);
return t;
}
// right shift
template<class T, class U>
struct right_shift_result {
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type =
typename promotion_policy::template right_shift_result<T, U>::type;
constexpr static const interval<typename base_type<T>::type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<typename base_type<U>::type> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
static_assert(t_interval.u >= 0, "negative values can't be shifted");
static_assert(u_interval.l <= 0, "shift count can't be negative");
static_assert(u_interval.l <= std::numeric_limits<T>::digits,
"shift count can't exceed argument size"
);
constexpr static const interval<checked_result<result_base_type>> r_interval{
right_shift<result_base_type>(t_interval, u_interval)
};
constexpr static const bool exception_possible() {
return r_interval.l.exception() || r_interval.u.exception();
}
using exception_policy = typename common_exception_policy<T, U>::type;
constexpr static result_base_type
right_shift(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
>> static_cast<result_base_type>(base_value(u))
;
}
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
static_assert(! exception_possible(), "no runtime check");
return right_shift(t, u);
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
static_assert(exception_possible(), "implement runtime check");
checked_result<result_base_type> r = checked::right_shift<result_base_type>(
base_value(t),
base_value(u)
);
if(!r.exception())
return static_cast<result_base_type>(r);
dispatch<exception_policy>(r);
return right_shift(t, u);
}
public:
using type = safe_base<
result_base_type,
r_interval.l.exception()
? std::numeric_limits<result_base_type>::min()
: static_cast<result_base_type>(r_interval.l),
r_interval.u.exception()
? std::numeric_limits<result_base_type>::max()
: static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static type return_value(const T & t, const U & u){
return return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
);
}
};
template<class T, class U>
typename boost::lazy_enable_if_c<
// handle safe<T> << int, int << safe<U>, safe<T> << safe<U>
// exclude std::istream << ...
(! std::is_base_of<std::ios_base, T>::value)
&& (
boost::numeric::is_safe<T>::value
||boost::numeric::is_safe<U>::value
),
right_shift_result<T, U>
>::type
constexpr operator>>(const T & t, const U & u){
// INT13-CPP
static_assert(
std::numeric_limits<T>::is_integer, "shifted value must be an integer"
);
static_assert(
std::numeric_limits<U>::is_integer, "shift amount must be an integer"
);
return right_shift_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator>>=(T & t, const U & u){
t = static_cast<T>(t >> u);
return t;
}
/////////////////////////////////////////////////////////////////
// bitwise operators
// operator |
template<class T, class U>
struct bitwise_or_result {
private:
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type =
typename promotion_policy::template bitwise_or_result<T, U>::type;
constexpr static const interval<typename base_type<T>::type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<typename base_type<U>::type> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
// when we or the temporary intervals above, we'll get a new interval
// with the correct range for the sum !
constexpr static const interval<checked_result<result_base_type>> r_interval =
bitwise_or<result_base_type>(t_interval, u_interval);
constexpr static const bool exception_possible() {
return r_interval.l.exception() || r_interval.u.exception();
}
using exception_policy = typename common_exception_policy<T, U>::type;
struct safe_type {
using type = safe_base<
result_base_type,
r_interval.l.exception()
? std::numeric_limits<result_base_type>::min()
: static_cast<result_base_type>(r_interval.l),
r_interval.u.exception()
? std::numeric_limits<result_base_type>::max()
: static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static const type make(const result_base_type & t){
return type(t, std::false_type());
}
};
struct unsafe_type {
using type = result_base_type;
constexpr static const type make(const result_base_type & t){
return t;
}
};
using type_helper = typename boost::mpl::if_c<
std::numeric_limits<result_base_type>::is_integer,
safe_type,
unsafe_type
>::type;
constexpr static result_base_type
bitwise_or(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
| static_cast<result_base_type>(base_value(u));
}
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
static_assert(! exception_possible(), "no runtime check");
return bitwise_or(t, u);
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
static_assert(exception_possible(), "implement runtime check");
checked_result<result_base_type> r = checked::bitwise_or<result_base_type>(
base_value(t),
base_value(u)
);
if(!r.exception())
return static_cast<result_base_type>(r);
dispatch<exception_policy>(r);
return bitwise_or(t, u);
}
public:
// lazy_enable_if_c depends on this
using type = typename type_helper::type;
constexpr static type return_value(const T & t, const U & u){
return type_helper::make( return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
));
}
};
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
typename bitwise_or_result<T, U>::type
>::type
constexpr operator|(const T & t, const U & u){
return bitwise_or_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator|=(T & t, const U & u){
t = static_cast<T>(t | u);
return t;
}
// operator &
template<class T, class U>
struct bitwise_and_result {
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type =
typename promotion_policy::template bitwise_and_result<T, U>::type;
constexpr static const interval<typename base_type<T>::type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<typename base_type<U>::type> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
// when we and the temporary intervals above, we'll get a new interval
// with the correct range for the sum !
constexpr static const interval<checked_result<result_base_type>> r_interval =
bitwise_and<result_base_type>(t_interval, u_interval);
constexpr static const bool exception_possible() {
return r_interval.l.exception() || r_interval.u.exception();
}
using exception_policy = typename common_exception_policy<T, U>::type;
struct safe_type {
using type = safe_base<
result_base_type,
r_interval.l.exception()
? std::numeric_limits<result_base_type>::min()
: static_cast<result_base_type>(r_interval.l),
r_interval.u.exception()
? std::numeric_limits<result_base_type>::max()
: static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static const type make(const result_base_type & t){
return type(t, std::false_type());
}
};
struct unsafe_type {
using type = result_base_type;
constexpr static const type make(const result_base_type & t){
return t;
}
};
using type_helper = typename boost::mpl::if_c<
std::numeric_limits<result_base_type>::is_integer,
safe_type,
unsafe_type
>::type;
constexpr static result_base_type
bitwise_and(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
& static_cast<result_base_type>(base_value(u))
;
}
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
static_assert(! exception_possible(), "no runtime check");
return bitwise_and(t, u);
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
static_assert(exception_possible(), "implement runtime check");
checked_result<result_base_type> r = checked::bitwise_and<result_base_type>(
base_value(t),
base_value(u)
);
dispatch<exception_policy>(r);
return bitwise_and(t, u);
}
public:
using type = typename type_helper::type;
constexpr static type return_value(const T & t, const U & u){
return type_helper::make( return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
));
}
};
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
typename bitwise_and_result<T, U>::type
>::type
constexpr operator&(const T & t, const U & u){
return bitwise_and_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator&=(T & t, const U & u){
t = static_cast<T>(t & u);
return t;
}
// operator ^
template<class T, class U>
struct bitwise_xor_result {
private:
using promotion_policy = typename common_promotion_policy<T, U>::type;
using result_base_type =
typename promotion_policy::template bitwise_xor_result<T, U>::type;
constexpr static const interval<typename base_type<T>::type> t_interval{
base_value(std::numeric_limits<T>::min()),
base_value(std::numeric_limits<T>::max())
};
constexpr static const interval<typename base_type<U>::type> u_interval{
base_value(std::numeric_limits<U>::min()),
base_value(std::numeric_limits<U>::max())
};
// when we xor the temporary intervals above, we'll get a new interval
// with the correct range for the sum !
constexpr static const interval<checked_result<result_base_type>> r_interval =
bitwise_xor<result_base_type>(t_interval, u_interval);
constexpr static const bool exception_possible() {
return r_interval.l.exception() || r_interval.u.exception();
}
using exception_policy = typename common_exception_policy<T, U>::type;
struct safe_type {
using type = safe_base<
result_base_type,
r_interval.l.exception()
? std::numeric_limits<result_base_type>::min()
: static_cast<result_base_type>(r_interval.l),
r_interval.u.exception()
? std::numeric_limits<result_base_type>::max()
: static_cast<result_base_type>(r_interval.u),
promotion_policy,
exception_policy
>;
constexpr static const type make(const result_base_type & t){
return type(t, std::false_type());
}
};
struct unsafe_type {
using type = result_base_type;
constexpr static const type make(const result_base_type & t){
return t;
}
};
using type_helper = typename boost::mpl::if_c<
std::numeric_limits<result_base_type>::is_integer,
safe_type,
unsafe_type
>::type;
constexpr static result_base_type
bitwise_xor(const T & t, const U & u){
return
static_cast<result_base_type>(base_value(t))
^ static_cast<result_base_type>(base_value(u));
}
// exception possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::true_type){
static_assert(exception_possible(), "implement runtime check");
checked_result<result_base_type> r = checked::bitwise_xor<result_base_type>(
base_value(t),
base_value(u)
);
if(!r.exception())
return static_cast<result_base_type>(r);
dispatch<exception_policy>(r);
return bitwise_xor(t, u);
}
// exception not possible
constexpr static result_base_type
return_value(const T & t, const U & u, std::false_type){
static_assert(! exception_possible(), "no runtime check");
return bitwise_xor(t, u);
}
public:
using type = typename type_helper::type;
constexpr static type return_value(const T & t, const U & u){
return type_helper::make( return_value(
t,
u,
typename std::integral_constant<bool, exception_possible()>()
));
}
};
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
typename bitwise_xor_result<T, U>::type
>::type
constexpr operator^(const T & t, const U & u){
return bitwise_xor_result<T, U>::return_value(t, u);
}
template<class T, class U>
typename std::enable_if<
boost::numeric::is_safe<T>::value
|| boost::numeric::is_safe<U>::value
,
T
>::type
constexpr operator^=(T & t, const U & u){
t = static_cast<T>(t ^ u);
return t;
}
/////////////////////////////////////////////////////////////////
// stream helpers
template<
class T,
T Min,
T Max,
class P, // promotion polic
class E // exception policy
>
template<
class CharT,
class Traits
>
void safe_base<T, Min, Max, P, E>::output(
std::basic_ostream<CharT, Traits> & os
) const {
os << (
(std::is_same<T, signed char>::value
|| std::is_same<T, unsigned char>::value
|| std::is_same<T, wchar_t>::value
) ?
static_cast<int>(m_t)
:
m_t
);
}
template<
class T,
T Min,
T Max,
class P, // promotion polic
class E // exception policy
>
template<
class CharT,
class Traits
>
void safe_base<T, Min, Max, P, E>::input(
std::basic_istream<CharT, Traits> & is
){
is >> m_t;
validated_cast(m_t); // no need to store result
if(is.fail()){
boost::numeric::dispatch<E>(
boost::numeric::safe_numerics_error::domain_error,
"error in file input"
);
}
}
} // numeric
} // boost
#endif // BOOST_NUMERIC_SAFE_BASE_OPERATIONS_HPP