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Move IsIntlike to type_traits.h

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I'll start using it outside safe_compare.h soon.

BUG=webrtc:7459

Review-Url: https://codereview.webrtc.org/2809513002
Cr-Commit-Position: refs/heads/master@{#17620}
This commit is contained in:
kwiberg
2017-04-10 06:56:58 -07:00
committed by Commit bot
parent 37e99fd3fa
commit b0f7e39fd4
2 changed files with 78 additions and 73 deletions
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88
webrtc/base/safe_compare.h
View File

@ -37,6 +37,8 @@
#include <type_traits>
#include <utility>
#include "webrtc/base/type_traits.h"
namespace rtc {
namespace safe_cmp {
@ -145,81 +147,21 @@ RTC_SAFECMP_MAKE_OP(GtOp, >)
RTC_SAFECMP_MAKE_OP(GeOp, >=)
#undef RTC_SAFECMP_MAKE_OP
// Determines if the given type is an enum that converts implicitly to
// an integral type.
template <typename T>
struct IsIntEnum {
private:
// This overload is used if the type is an enum, and unary plus
// compiles and turns it into an integral type.
template <typename X,
typename std::enable_if<
std::is_enum<X>::value &&
std::is_integral<decltype(+std::declval<X>())>::value>::type* =
nullptr>
static int Test(int);
// Otherwise, this overload is used.
template <typename>
static char Test(...);
public:
static constexpr bool value =
std::is_same<decltype(Test<typename std::remove_reference<T>::type>(0)),
int>::value;
};
// Determines if the given type is integral, or an enum that
// converts implicitly to an integral type.
template <typename T>
struct IsIntlike {
private:
using X = typename std::remove_reference<T>::type;
public:
static constexpr bool value =
std::is_integral<X>::value || IsIntEnum<X>::value;
};
namespace test_enum_intlike {
enum E1 { e1 };
enum { e2 };
enum class E3 { e3 };
struct S {};
static_assert(IsIntEnum<E1>::value, "");
static_assert(IsIntEnum<decltype(e2)>::value, "");
static_assert(!IsIntEnum<E3>::value, "");
static_assert(!IsIntEnum<int>::value, "");
static_assert(!IsIntEnum<float>::value, "");
static_assert(!IsIntEnum<S>::value, "");
static_assert(IsIntlike<E1>::value, "");
static_assert(IsIntlike<decltype(e2)>::value, "");
static_assert(!IsIntlike<E3>::value, "");
static_assert(IsIntlike<int>::value, "");
static_assert(!IsIntlike<float>::value, "");
static_assert(!IsIntlike<S>::value, "");
} // test_enum_intlike
} // namespace safe_cmp_impl
#define RTC_SAFECMP_MAKE_FUN(name) \
template <typename T1, typename T2, \
typename std::enable_if< \
safe_cmp_impl::IsIntlike<T1>::value && \
safe_cmp_impl::IsIntlike<T2>::value>::type* = nullptr> \
inline bool name(T1 a, T2 b) { \
/* Unary plus here turns enums into real integral types. */ \
return safe_cmp_impl::Cmp<safe_cmp_impl::name##Op>(+a, +b); \
} \
template <typename T1, typename T2, \
typename std::enable_if< \
!safe_cmp_impl::IsIntlike<T1>::value || \
!safe_cmp_impl::IsIntlike<T2>::value>::type* = nullptr> \
inline bool name(T1&& a, T2&& b) { \
return safe_cmp_impl::name##Op::Op(a, b); \
#define RTC_SAFECMP_MAKE_FUN(name) \
template <typename T1, typename T2, \
typename std::enable_if<IsIntlike<T1>::value && \
IsIntlike<T2>::value>::type* = nullptr> \
inline bool name(T1 a, T2 b) { \
/* Unary plus here turns enums into real integral types. */ \
return safe_cmp_impl::Cmp<safe_cmp_impl::name##Op>(+a, +b); \
} \
template <typename T1, typename T2, \
typename std::enable_if<!IsIntlike<T1>::value || \
!IsIntlike<T2>::value>::type* = nullptr> \
inline bool name(T1&& a, T2&& b) { \
return safe_cmp_impl::name##Op::Op(a, b); \
}
RTC_SAFECMP_MAKE_FUN(Eq)
RTC_SAFECMP_MAKE_FUN(Ne)

63
webrtc/base/type_traits.h
View File

@ -72,6 +72,69 @@ static_assert(!HasDataAndSize<Test4, int>::value,
} // namespace test_has_data_and_size
namespace type_traits_impl {
// Determines if the given type is an enum that converts implicitly to
// an integral type.
template <typename T>
struct IsIntEnum {
private:
// This overload is used if the type is an enum, and unary plus
// compiles and turns it into an integral type.
template <typename X,
typename std::enable_if<
std::is_enum<X>::value &&
std::is_integral<decltype(+std::declval<X>())>::value>::type* =
nullptr>
static int Test(int);
// Otherwise, this overload is used.
template <typename>
static char Test(...);
public:
static constexpr bool value =
std::is_same<decltype(Test<typename std::remove_reference<T>::type>(0)),
int>::value;
};
} // namespace type_traits_impl
// Determines if the given type is integral, or an enum that
// converts implicitly to an integral type.
template <typename T>
struct IsIntlike {
private:
using X = typename std::remove_reference<T>::type;
public:
static constexpr bool value =
std::is_integral<X>::value || type_traits_impl::IsIntEnum<X>::value;
};
namespace test_enum_intlike {
enum E1 { e1 };
enum { e2 };
enum class E3 { e3 };
struct S {};
static_assert(type_traits_impl::IsIntEnum<E1>::value, "");
static_assert(type_traits_impl::IsIntEnum<decltype(e2)>::value, "");
static_assert(!type_traits_impl::IsIntEnum<E3>::value, "");
static_assert(!type_traits_impl::IsIntEnum<int>::value, "");
static_assert(!type_traits_impl::IsIntEnum<float>::value, "");
static_assert(!type_traits_impl::IsIntEnum<S>::value, "");
static_assert(IsIntlike<E1>::value, "");
static_assert(IsIntlike<decltype(e2)>::value, "");
static_assert(!IsIntlike<E3>::value, "");
static_assert(IsIntlike<int>::value, "");
static_assert(!IsIntlike<float>::value, "");
static_assert(!IsIntlike<S>::value, "");
} // test_enum_intlike
} // namespace rtc
#endif // WEBRTC_BASE_TYPE_TRAITS_H_