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Implement n3658 - Compile-time integer sequences

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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@185343 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Marshall Clow
2013-07-01 16:26:55 +00:00
parent 11b87182b0
commit 7ec46bc422
7 changed files with 331 additions and 0 deletions
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83
include/utility
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@@ -117,6 +117,27 @@ template<size_t I, class T1, class T2>
typename tuple_element<I, std::pair<T1, T2> >::type&&
get(std::pair<T1, T2>&&) noexcept;
// C++14
template<class T, T... I>
struct integer_sequence
{
typedef T value_type;
static constexpr size_t size() noexcept;
};
template<size_t... I>
using index_sequence = integer_sequence<size_t, I...>;
template<class T, T N>
using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
template<size_t N>
using make_index_sequence = make_integer_sequence<size_t, N>;
template<class... T>
using index_sequence_for = make_index_sequence<sizeof...(T)>;
} // std
*/
@@ -578,6 +599,68 @@ get(pair<_T1, _T2>&& __p) _NOEXCEPT
#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES
#if _LIBCPP_STD_VER > 11
template<class _Tp, _Tp... _Ip>
struct integer_sequence
{
typedef _Tp value_type;
static_assert( is_integral<_Tp>::value,
"std::integer_sequence can only be instantiated with an integral type" );
static
_LIBCPP_INLINE_VISIBILITY
constexpr
size_t
size() noexcept { return sizeof...(_Ip); }
};
template<size_t... _Ip>
using index_sequence = integer_sequence<size_t, _Ip...>;
template <class _Tp, _Tp _Sp, _Tp _Ep, class _IntSequence>
struct __make_integer_sequence_unchecked;
template <class _Tp, _Tp _Sp, _Tp _Ep, _Tp ..._Indices>
struct __make_integer_sequence_unchecked<_Tp, _Sp, _Ep,
integer_sequence<_Tp, _Indices...>>
{
typedef typename __make_integer_sequence_unchecked
<
_Tp, _Sp+1, _Ep,
integer_sequence<_Tp, _Indices..., _Sp>
>::type type;
};
template <class _Tp, _Tp _Ep, _Tp ..._Indices>
struct __make_integer_sequence_unchecked<_Tp, _Ep, _Ep,
integer_sequence<_Tp, _Indices...>>
{
typedef integer_sequence<_Tp, _Indices...> type;
};
template <class _Tp, _Tp _Ep>
struct __make_integer_sequence
{
static_assert(is_integral<_Tp>::value,
"std::make_integer_sequence can only be instantiated with an integral type" );
static_assert(0 <= _Ep, "std::make_integer_sequence input shall not be negative");
typedef typename __make_integer_sequence_unchecked
<
_Tp, 0, _Ep, integer_sequence<_Tp>
>::type type;
};
template<class _Tp, _Tp _Np>
using make_integer_sequence = typename __make_integer_sequence<_Tp, _Np>::type;
template<size_t _Np>
using make_index_sequence = make_integer_sequence<size_t, _Np>;
template<class... _Tp>
using index_sequence_for = make_index_sequence<sizeof...(_Tp)>;
#endif // _LIBCPP_STD_VER > 11
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP_UTILITY