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