/src/libreoffice/include/o3tl/unsafe_downcast.hxx
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1 | | /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ |
2 | | /* |
3 | | * This file is part of the LibreOffice project. |
4 | | * |
5 | | * This Source Code Form is subject to the terms of the Mozilla Public |
6 | | * License, v. 2.0. If a copy of the MPL was not distributed with this |
7 | | * file, You can obtain one at http://mozilla.org/MPL/2.0/. |
8 | | */ |
9 | | |
10 | | #ifndef INCLUDED_O3TL_UNSAFE_DOWNCAST_HXX |
11 | | #define INCLUDED_O3TL_UNSAFE_DOWNCAST_HXX |
12 | | |
13 | | #include <cassert> |
14 | | #include <type_traits> |
15 | | |
16 | | namespace o3tl |
17 | | { |
18 | | // Do a downcast from polymorphic `BasePtr` to `DerivedPtr` when it is known that `p` is actually |
19 | | // pointing to an object of derived type (or is a nullptr). This is potentially cheaper than |
20 | | // dynamic_cast and helps to avoid Coverity warnings about unchecked dynamic_cast. |
21 | | template <typename DerivedPtr, typename BasePtr> |
22 | | std::enable_if_t< |
23 | | (std::is_pointer_v< |
24 | | DerivedPtr> && std::is_pointer_v<BasePtr> && std::is_base_of_v<std::remove_pointer_t<BasePtr>, std::remove_pointer_t<DerivedPtr>>), |
25 | | DerivedPtr> |
26 | | unsafe_downcast(BasePtr p) |
27 | 0 | { |
28 | | assert(p == nullptr || dynamic_cast<DerivedPtr>(p) != nullptr); |
29 | 0 | return static_cast<DerivedPtr>(p); |
30 | 0 | } |
31 | | } |
32 | | |
33 | | #endif |
34 | | |
35 | | /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |