Better narrow_cast debug.

GitOrigin-RevId: 253b2b472e6e605a42f9b6ec2c3a59a6fa6afa0b
This commit is contained in:
levlam 2018-07-22 01:09:10 +03:00
parent 3afcad7a5e
commit dae614cf70

View File

@ -296,23 +296,34 @@ template <class T>
struct safe_undeflying_type<T, std::enable_if_t<std::is_enum<T>::value>> { struct safe_undeflying_type<T, std::enable_if_t<std::is_enum<T>::value>> {
using type = std::underlying_type_t<T>; using type = std::underlying_type_t<T>;
}; };
class NarrowCast {
const char *file_;
int line_;
public:
NarrowCast(const char *file, int line) : file_(file), line_(line) {
}
template <class R, class A>
R cast(const A &a) {
using RT = typename safe_undeflying_type<R>::type;
using AT = typename safe_undeflying_type<A>::type;
static_assert(std::is_integral<RT>::value, "expected integral type to cast to");
static_assert(std::is_integral<AT>::value, "expected integral type to cast from");
auto r = R(a);
CHECK(A(r) == a) << static_cast<AT>(a) << " " << static_cast<RT>(r) << " " << file_ << " " << line_;
CHECK((is_same_signedness<RT, AT>::value) || ((static_cast<RT>(r) < RT{}) == (static_cast<AT>(a) < AT{})))
<< static_cast<AT>(a) << " " << static_cast<RT>(r) << " " << file_ << " " << line_;
return r;
}
};
} // namespace detail } // namespace detail
template <class R, class A> #define narrow_cast detail::NarrowCast(__FILE__, __LINE__).cast
R narrow_cast(const A &a) {
using RT = typename detail::safe_undeflying_type<R>::type;
using AT = typename detail::safe_undeflying_type<A>::type;
static_assert(std::is_integral<RT>::value, "expected integral type to cast to");
static_assert(std::is_integral<AT>::value, "expected integral type to cast from");
auto r = R(a);
CHECK(A(r) == a) << static_cast<AT>(a) << " " << static_cast<RT>(r);
CHECK((detail::is_same_signedness<RT, AT>::value) || ((static_cast<RT>(r) < RT{}) == (static_cast<AT>(a) < AT{})))
<< static_cast<AT>(a) << " " << static_cast<RT>(r);
return r;
}
template <class R, class A> template <class R, class A>
Result<R> narrow_cast_safe(const A &a) { Result<R> narrow_cast_safe(const A &a) {