[libcxx] r185343 - Implement n3658 - Compile-time integer sequences
Richard Smith
richard at metafoo.co.uk
Mon Jul 1 10:43:29 PDT 2013
On Mon, Jul 1, 2013 at 9:26 AM, Marshall Clow <mclow at qualcomm.com> wrote:
> Author: marshall
> Date: Mon Jul 1 11:26:55 2013
> New Revision: 185343
>
> URL: http://llvm.org/viewvc/llvm-project?rev=185343&view=rev
> Log:
> Implement n3658 - Compile-time integer sequences
>
> Added:
> libcxx/trunk/test/utilities/intseq/
> libcxx/trunk/test/utilities/intseq/intseq.general/
> libcxx/trunk/test/utilities/intseq/intseq.general/integer_seq.pass.cpp
> libcxx/trunk/test/utilities/intseq/intseq.intseq/
> libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.fail.cpp
> libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.pass.cpp
> libcxx/trunk/test/utilities/intseq/intseq.make/
> libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
> libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.pass.cpp
> libcxx/trunk/test/utilities/intseq/nothing_to_do.pass.cpp
> Modified:
> libcxx/trunk/include/utility
>
> Modified: libcxx/trunk/include/utility
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/utility?rev=185343&r1=185342&r2=185343&view=diff
> ==============================================================================
> --- libcxx/trunk/include/utility (original)
> +++ libcxx/trunk/include/utility Mon Jul 1 11:26:55 2013
> @@ -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>
This is O(n^2). You can do it in O(n log n):
template<typename T, T N, T Parity> struct __make_integer_sequence;
template<typename T, T N> using make_integer_sequence =
__make_integer_sequence<T, N, N % 2>::type;
template<typename T> struct __make_integer_sequence<T, 0, 0> { typedef
integer_sequence<T> type; };
template<typename T> struct __make_integer_sequence<T, 1, 1> { typedef
integer_sequence<T, 0> type; };
template<typename T, T ...Extra> struct __make_integer_sequence_impl;
template<typename T, T ...N, T ...Extra> struct
__make_integer_sequence_impl<integer_sequence<T, N...>, Extra...> {
typedef integer_sequence<T, N..., sizeof...(N) + N..., Extra...> type;
};
template<typename T, T N> struct __make_integer_sequence<T, N, 0> {
typedef __make_integer_sequence_impl<make_integer_sequence<T, N /
2>>::type type;
};
template<typename T, T N> struct __make_integer_sequence<T, N, 1> {
typedef __make_integer_sequence_impl<make_integer_sequence<T, N /
2>, N>::type type;
};
> + >::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
>
> Added: libcxx/trunk/test/utilities/intseq/intseq.general/integer_seq.pass.cpp
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/utilities/intseq/intseq.general/integer_seq.pass.cpp?rev=185343&view=auto
> ==============================================================================
> --- libcxx/trunk/test/utilities/intseq/intseq.general/integer_seq.pass.cpp (added)
> +++ libcxx/trunk/test/utilities/intseq/intseq.general/integer_seq.pass.cpp Mon Jul 1 11:26:55 2013
> @@ -0,0 +1,86 @@
> +//===----------------------------------------------------------------------===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is dual licensed under the MIT and the University of Illinois Open
> +// Source Licenses. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +// <utility>
> +
> +// class make_integer_sequence
> +
> +#include <tuple>
> +#include <utility>
> +#include <type_traits>
> +#include <cassert>
> +
> +#if _LIBCPP_STD_VER > 11
> +
> +template <typename AtContainer, typename T, T... I>
> +auto extract ( const AtContainer &t, const std::integer_sequence<T, I...> idx )
> +-> decltype ( std::make_tuple ( std::get<I>(t)... ))
> +{ return std::make_tuple ( std::get<I>(t)... ); }
> +
> +#endif // _LIBCPP_STD_VER > 11
> +
> +int main()
> +{
> +#if _LIBCPP_STD_VER > 11
> +
> +// Make a couple of sequences
> + using int3 = std::make_integer_sequence<int, 3>; // generates int: 0,1,2
> + using size7 = std::make_integer_sequence<size_t, 7>; // generates size_t: 0,1,2,3,4,5,6
> + using size4 = std::make_index_sequence<4>; // generates size_t: 0,1,2,3
> + using size2 = std::index_sequence_for<int, size_t>; // generates size_t: 0,1
> + using intmix = std::integer_sequence<int, 9, 8, 7, 2>; // generates int: 9,8,7,2
> + using sizemix = std::index_sequence<1, 1, 2, 3, 5>; // generates size_t: 1,1,2,3,5
> +
> +// Make sure they're what we expect
> + static_assert ( std::is_same<int3::value_type, int>::value, "int3 type wrong" );
> + static_assert ( int3::size () == 3, "int3 size wrong" );
> +
> + static_assert ( std::is_same<size7::value_type, size_t>::value, "size7 type wrong" );
> + static_assert ( size7::size () == 7, "size7 size wrong" );
> +
> + static_assert ( std::is_same<size4::value_type, size_t>::value, "size4 type wrong" );
> + static_assert ( size4::size () == 4, "size4 size wrong" );
> +
> + static_assert ( std::is_same<size2::value_type, size_t>::value, "size2 type wrong" );
> + static_assert ( size2::size () == 2, "size2 size wrong" );
> +
> + static_assert ( std::is_same<intmix::value_type, int>::value, "intmix type wrong" );
> + static_assert ( intmix::size () == 4, "intmix size wrong" );
> +
> + static_assert ( std::is_same<sizemix::value_type, size_t>::value, "sizemix type wrong" );
> + static_assert ( sizemix::size () == 5, "sizemix size wrong" );
> +
> + auto tup = std::make_tuple ( 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 );
> +
> +// Use them
> + auto t3 = extract ( tup, int3() );
> + static_assert ( std::tuple_size<decltype(t3)>::value == int3::size (), "t3 size wrong");
> + assert ( t3 == std::make_tuple ( 10, 11, 12 ));
> +
> + auto t7 = extract ( tup, size7 ());
> + static_assert ( std::tuple_size<decltype(t7)>::value == size7::size (), "t7 size wrong");
> + assert ( t7 == std::make_tuple ( 10, 11, 12, 13, 14, 15, 16 ));
> +
> + auto t4 = extract ( tup, size4 ());
> + static_assert ( std::tuple_size<decltype(t4)>::value == size4::size (), "t4 size wrong");
> + assert ( t4 == std::make_tuple ( 10, 11, 12, 13 ));
> +
> + auto t2 = extract ( tup, size2 ());
> + static_assert ( std::tuple_size<decltype(t2)>::value == size2::size (), "t2 size wrong");
> + assert ( t2 == std::make_tuple ( 10, 11 ));
> +
> + auto tintmix = extract ( tup, intmix ());
> + static_assert ( std::tuple_size<decltype(tintmix)>::value == intmix::size (), "tintmix size wrong");
> + assert ( tintmix == std::make_tuple ( 19, 18, 17, 12 ));
> +
> + auto tsizemix = extract ( tup, sizemix ());
> + static_assert ( std::tuple_size<decltype(tsizemix)>::value == sizemix::size (), "tsizemix size wrong");
> + assert ( tsizemix == std::make_tuple ( 11, 11, 12, 13, 15 ));
> +#endif // _LIBCPP_STD_VER > 11
> +}
>
> Added: libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.fail.cpp
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.fail.cpp?rev=185343&view=auto
> ==============================================================================
> --- libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.fail.cpp (added)
> +++ libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.fail.cpp Mon Jul 1 11:26:55 2013
> @@ -0,0 +1,38 @@
> +//===----------------------------------------------------------------------===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is dual licensed under the MIT and the University of Illinois Open
> +// Source Licenses. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +// <utility>
> +
> +// template<class T, T... I>
> +// struct integer_sequence
> +// {
> +// typedef T type;
> +//
> +// static constexpr size_t size() noexcept;
> +// };
> +
> +// This test is a conforming extension. The extension turns undefined behavior
> +// into a compile-time error.
> +
> +#include <utility>
> +
> +int main()
> +{
> +#if _LIBCPP_STD_VER > 11
> +
> +// Should fail to compile, since float is not an integral type
> + using floatmix = std::integer_sequence<float>;
> + floatmix::value_type I;
> +
> +#else
> +
> +X
> +
> +#endif // _LIBCPP_STD_VER > 11
> +}
>
> Added: libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.pass.cpp
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.pass.cpp?rev=185343&view=auto
> ==============================================================================
> --- libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.pass.cpp (added)
> +++ libcxx/trunk/test/utilities/intseq/intseq.intseq/integer_seq.pass.cpp Mon Jul 1 11:26:55 2013
> @@ -0,0 +1,48 @@
> +//===----------------------------------------------------------------------===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is dual licensed under the MIT and the University of Illinois Open
> +// Source Licenses. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +// <utility>
> +
> +// template<class T, T... I>
> +// struct integer_sequence
> +// {
> +// typedef T type;
> +//
> +// static constexpr size_t size() noexcept;
> +// };
> +
> +#include <utility>
> +#include <type_traits>
> +#include <cassert>
> +
> +int main()
> +{
> +#if _LIBCPP_STD_VER > 11
> +
> +// Make a few of sequences
> + using int3 = std::integer_sequence<int, 3, 2, 1>;
> + using size1 = std::integer_sequence<size_t, 7>;
> + using ushort2 = std::integer_sequence<unsigned short, 4, 6>;
> + using bool0 = std::integer_sequence<bool>;
> +
> +// Make sure they're what we expect
> + static_assert ( std::is_same<int3::value_type, int>::value, "int3 type wrong" );
> + static_assert ( int3::size() == 3, "int3 size wrong" );
> +
> + static_assert ( std::is_same<size1::value_type, size_t>::value, "size1 type wrong" );
> + static_assert ( size1::size() == 1, "size1 size wrong" );
> +
> + static_assert ( std::is_same<ushort2::value_type, unsigned short>::value, "ushort2 type wrong" );
> + static_assert ( ushort2::size() == 2, "ushort2 size wrong" );
> +
> + static_assert ( std::is_same<bool0::value_type, bool>::value, "bool0 type wrong" );
> + static_assert ( bool0::size() == 0, "bool0 size wrong" );
> +
> +#endif // _LIBCPP_STD_VER > 11
> +}
>
> Added: libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.fail.cpp?rev=185343&view=auto
> ==============================================================================
> --- libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.fail.cpp (added)
> +++ libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.fail.cpp Mon Jul 1 11:26:55 2013
> @@ -0,0 +1,30 @@
> +//===----------------------------------------------------------------------===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is dual licensed under the MIT and the University of Illinois Open
> +// Source Licenses. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +// <utility>
> +
> +// template<class T, T N>
> +// using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
> +
> +#include <utility>
> +#include <type_traits>
> +#include <cassert>
> +
> +int main()
> +{
> +#if _LIBCPP_STD_VER > 11
> +
> + std::make_integer_sequence<int, -3>::value_type i;
> +
> +#else
> +
> +X
> +
> +#endif // _LIBCPP_STD_VER > 11
> +}
>
> Added: libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.pass.cpp
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.pass.cpp?rev=185343&view=auto
> ==============================================================================
> --- libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.pass.cpp (added)
> +++ libcxx/trunk/test/utilities/intseq/intseq.make/make_integer_seq.pass.cpp Mon Jul 1 11:26:55 2013
> @@ -0,0 +1,34 @@
> +//===----------------------------------------------------------------------===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is dual licensed under the MIT and the University of Illinois Open
> +// Source Licenses. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +// <utility>
> +
> +// template<class T, T N>
> +// using make_integer_sequence = integer_sequence<T, 0, 1, ..., N-1>;
> +
> +#include <utility>
> +#include <type_traits>
> +#include <cassert>
> +
> +int main()
> +{
> +#if _LIBCPP_STD_VER > 11
> +
> + static_assert(std::is_same<std::make_integer_sequence<int, 0>, std::integer_sequence<int>>::value, "");
> + static_assert(std::is_same<std::make_integer_sequence<int, 1>, std::integer_sequence<int, 0>>::value, "");
> + static_assert(std::is_same<std::make_integer_sequence<int, 2>, std::integer_sequence<int, 0, 1>>::value, "");
> + static_assert(std::is_same<std::make_integer_sequence<int, 3>, std::integer_sequence<int, 0, 1, 2>>::value, "");
> +
> + static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 0>, std::integer_sequence<unsigned long long>>::value, "");
> + static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 1>, std::integer_sequence<unsigned long long, 0>>::value, "");
> + static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 2>, std::integer_sequence<unsigned long long, 0, 1>>::value, "");
> + static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 3>, std::integer_sequence<unsigned long long, 0, 1, 2>>::value, "");
> +
> +#endif // _LIBCPP_STD_VER > 11
> +}
>
> Added: libcxx/trunk/test/utilities/intseq/nothing_to_do.pass.cpp
> URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/utilities/intseq/nothing_to_do.pass.cpp?rev=185343&view=auto
> ==============================================================================
> --- libcxx/trunk/test/utilities/intseq/nothing_to_do.pass.cpp (added)
> +++ libcxx/trunk/test/utilities/intseq/nothing_to_do.pass.cpp Mon Jul 1 11:26:55 2013
> @@ -0,0 +1,12 @@
> +//===----------------------------------------------------------------------===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is dual licensed under the MIT and the University of Illinois Open
> +// Source Licenses. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +int main()
> +{
> +}
>
>
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