| 1 | //===----------------------------------------------------------------------===// |
| 2 | // |
| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| 4 | // See https://llvm.org/LICENSE.txt for license information. |
| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| 6 | // |
| 7 | //===----------------------------------------------------------------------===// |
| 8 | |
| 9 | #ifndef _LIBCPP___ALGORITHM_SPECIALIZED_ALGORITHMS_H |
| 10 | #define _LIBCPP___ALGORITHM_SPECIALIZED_ALGORITHMS_H |
| 11 | |
| 12 | #include <__config> |
| 13 | |
| 14 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| 15 | # pragma GCC system_header |
| 16 | #endif |
| 17 | |
| 18 | _LIBCPP_BEGIN_NAMESPACE_STD |
| 19 | |
| 20 | namespace _Algorithm { |
| 21 | struct __copy {}; |
| 22 | struct __fill_n {}; |
| 23 | struct __for_each {}; |
| 24 | } // namespace _Algorithm |
| 25 | |
| 26 | template <class> |
| 27 | struct __single_iterator; |
| 28 | |
| 29 | template <class, class> |
| 30 | struct __iterator_pair; |
| 31 | |
| 32 | template <class> |
| 33 | struct __single_range; |
| 34 | |
| 35 | // This struct allows specializing algorithms for specific arguments. This is useful when we know a more efficient |
| 36 | // algorithm implementation for e.g. library-defined iterators. _Alg is one of tags defined inside the _Algorithm |
| 37 | // namespace above. _Ranges is an essentially arbitrary subset of the arguments to the algorithm that are used for |
| 38 | // dispatching. This set is specific to the algorithm: look at each algorithm to see which arguments they use for |
| 39 | // dispatching to specialized algorithms. |
| 40 | // |
| 41 | // A specialization of `__specialized_algorithm` has to define `__has_algorithm` to true for the specialized algorithm |
| 42 | // to be used. This is intended for cases where iterators can do generic unwrapping and forward to a different |
| 43 | // specialization of `__specialized_algorithm`. |
| 44 | // |
| 45 | // If __has_algorithm is true, there has to be an operator() which will get called with the actual arguments to the |
| 46 | // algorithm. |
| 47 | template <class _Alg, class... _Ranges> |
| 48 | struct __specialized_algorithm { |
| 49 | static const bool __has_algorithm = false; |
| 50 | }; |
| 51 | |
| 52 | _LIBCPP_END_NAMESPACE_STD |
| 53 | |
| 54 | #endif // _LIBCPP___ALGORITHM_SPECIALIZED_ALGORITHMS_H |