47 lines
1.5 KiB
C++
47 lines
1.5 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2017 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef CRUFT_UTIL_TYPEIDX_HPP
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#define CRUFT_UTIL_TYPEIDX_HPP
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#include <cstdint>
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namespace util {
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namespace detail { std::uintptr_t typeidx_next (void); }
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/// return a globally unique runtime ID for a given type.
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///
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/// this is intended to be used as a lightweight type check for variants
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/// and such without requiring RTTI.
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///
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/// the identifier is constructed at runtime and is not guaranteed to be
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/// stable across executions (particularly in the case of threads and
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/// other non-determinism).
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///
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/// the range of identifiers is _probably_ contiguous starting from zero.
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/// this should not be relied upon for correctness, but may be used for
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/// performance concerns.
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template <typename T>
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std::uintptr_t
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typeidx (void)
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{
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static auto id = detail::typeidx_next ();
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return id;
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}
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}
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#endif
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