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Reduced copying cost of tuple_cat from quadratic to linear.

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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@121655 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Howard Hinnant 2010-12-12 23:04:37 +00:00
parent 0e1493ec5e
commit e48e36623b
1 changed files with 73 additions and 36 deletions

109
include/tuple

@ -804,47 +804,84 @@ tuple_cat()
return tuple<>();
}
template <class _Tuple>
inline _LIBCPP_INLINE_VISIBILITY
typename __tuple_cat_return<_Tuple>::type
tuple_cat(_Tuple&& __tpl)
{
typedef typename __tuple_cat_return<_Tuple>::type _R;
return _R(_STD::forward<_Tuple>(__tpl));
}
template <class _R, class _Indices, class _Tuple0, class ..._Tuples>
struct __tuple_cat_return_ref_imp;
template <class _Tuple0, size_t ..._I0, class _Tuple1, size_t ..._I1>
inline _LIBCPP_INLINE_VISIBILITY
typename __tuple_cat_return<_Tuple0, _Tuple1>::type
__tuple_cat(_Tuple0&& __t0, __tuple_indices<_I0...>,
_Tuple1&& __t1, __tuple_indices<_I1...>)
{
typedef typename __tuple_cat_return<_Tuple0, _Tuple1>::type _R;
return _R(get<_I0>(_STD::forward<_Tuple0>(__t0))...,
get<_I1>(_STD::forward<_Tuple1>(__t1))...);
}
template <class _Tuple0, class _Tuple1>
inline _LIBCPP_INLINE_VISIBILITY
typename __tuple_cat_return<_Tuple0, _Tuple1>::type
tuple_cat(_Tuple0&& __t0, _Tuple1&& __t1)
template <class ..._Types, size_t ..._I0, class _Tuple0>
struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>, _Tuple0>
{
typedef typename remove_reference<_Tuple0>::type _T0;
typedef typename remove_reference<_Tuple1>::type _T1;
return __tuple_cat(_STD::forward<_Tuple0>(__t0),
typename __make_tuple_indices<tuple_size<_T0>::value>::type(),
_STD::forward<_Tuple1>(__t1),
typename __make_tuple_indices<tuple_size<_T1>::value>::type());
}
typedef tuple<_Types..., typename __apply_cv<_Tuple0,
typename tuple_element<_I0, _T0>::type>::type&&...> type;
};
template <class _Tuple0, class _Tuple1, class... _Tuples>
inline _LIBCPP_INLINE_VISIBILITY
typename __tuple_cat_return<_Tuple0, _Tuple1, _Tuples...>::type
tuple_cat(_Tuple0&& __t0, _Tuple1&& __t1, _Tuples&&... __tpls)
template <class ..._Types, size_t ..._I0, class _Tuple0, class _Tuple1, class ..._Tuples>
struct __tuple_cat_return_ref_imp<tuple<_Types...>, __tuple_indices<_I0...>,
_Tuple0, _Tuple1, _Tuples...>
: public __tuple_cat_return_ref_imp<
tuple<_Types..., typename __apply_cv<_Tuple0,
typename tuple_element<_I0,
typename remove_reference<_Tuple0>::type>::type>::type&&...>,
typename __make_tuple_indices<tuple_size<typename
remove_reference<_Tuple1>::type>::value>::type,
_Tuple1, _Tuples...>
{
return tuple_cat(tuple_cat(_STD::forward<_Tuple0>(__t0),
_STD::forward<_Tuple1>(__t1)),
_STD::forward<_Tuples>(__tpls)...);
};
template <class _Tuple0, class ..._Tuples>
struct __tuple_cat_return_ref
: public __tuple_cat_return_ref_imp<tuple<>,
typename __make_tuple_indices<
tuple_size<typename remove_reference<_Tuple0>::type>::value
>::type, _Tuple0, _Tuples...>
{
};
template <class _Types, class _I0, class _J0>
struct __tuple_cat;
template <class ..._Types, size_t ..._I0, size_t ..._J0>
struct __tuple_cat<tuple<_Types...>, __tuple_indices<_I0...>, __tuple_indices<_J0...>>
{
template <class _Tuple0>
_LIBCPP_INLINE_VISIBILITY
typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&>::type
operator()(tuple<_Types...> __t, _Tuple0&& __t0)
{
return _STD::forward_as_tuple(_STD::forward<_Types>(get<_I0>(__t))...,
get<_J0>(_STD::forward<_Tuple0>(__t0))...);
}
template <class _Tuple0, class _Tuple1, class ..._Tuples>
_LIBCPP_INLINE_VISIBILITY
typename __tuple_cat_return_ref<tuple<_Types...>&&, _Tuple0&&, _Tuple1&&, _Tuples&&...>::type
operator()(tuple<_Types...> __t, _Tuple0&& __t0, _Tuple1&& __t1, _Tuples&& ...__tpls)
{
typedef typename remove_reference<_Tuple0>::type _T0;
typedef typename remove_reference<_Tuple1>::type _T1;
return __tuple_cat<
tuple<_Types..., typename __apply_cv<_Tuple0, typename tuple_element<_J0, _T0>::type>::type&&...>,
typename __make_tuple_indices<sizeof ...(_Types) + tuple_size<_T0>::value>::type,
typename __make_tuple_indices<tuple_size<_T1>::value>::type>()
(_STD::forward_as_tuple(
_STD::forward<_Types>(get<_I0>(__t))...,
get<_J0>(_STD::forward<_Tuple0>(__t0))...
),
_STD::forward<_Tuple1>(__t1),
_STD::forward<_Tuples>(__tpls)...);
}
};
template <class _Tuple0, class... _Tuples>
inline _LIBCPP_INLINE_VISIBILITY
typename __tuple_cat_return<_Tuple0, _Tuples...>::type
tuple_cat(_Tuple0&& __t0, _Tuples&&... __tpls)
{
typedef typename remove_reference<_Tuple0>::type _T0;
return __tuple_cat<tuple<>, __tuple_indices<>,
typename __make_tuple_indices<tuple_size<_T0>::value>::type>()
(tuple<>(), _STD::forward<_Tuple0>(__t0),
_STD::forward<_Tuples>(__tpls)...);
}
template <class ..._Tp, class _Alloc>