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Diffstat (limited to '')
| -rw-r--r-- | include/o3tl/unsafe_downcast.hxx | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/include/o3tl/unsafe_downcast.hxx b/include/o3tl/unsafe_downcast.hxx new file mode 100644 index 000000000..b49994eff --- /dev/null +++ b/include/o3tl/unsafe_downcast.hxx @@ -0,0 +1,35 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#ifndef INCLUDED_O3TL_UNSAFE_DOWNCAST_HXX +#define INCLUDED_O3TL_UNSAFE_DOWNCAST_HXX + +#include <cassert> +#include <type_traits> + +namespace o3tl +{ +// Do a downcast from polymorphic `BasePtr` to `DerivedPtr` when it is known that `p` is actually +// pointing to an object of derived type (or is a nullptr). This is potentially cheaper than +// dynamic_cast and helps to avoid Coverity warnings about unchecked dynamic_cast. +template <typename DerivedPtr, typename BasePtr> +std::enable_if_t< + (std::is_pointer_v< + DerivedPtr> && std::is_pointer_v<BasePtr> && std::is_base_of_v<std::remove_pointer_t<BasePtr>, std::remove_pointer_t<DerivedPtr>>), + DerivedPtr> +unsafe_downcast(BasePtr p) +{ + assert(p == nullptr || dynamic_cast<DerivedPtr>(p) != nullptr); + return static_cast<DerivedPtr>(p); +} +} + +#endif + +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |