Files
UltraGrid/src/utils/ref_count.hpp
Martin Pulec 42e5fd03e1 moved ref_counter to separate source
It is rarely used and we don't need to spoil c++ sources using misc.h
with <optional> header.
2022-11-16 09:07:15 +01:00

62 lines
2.3 KiB
C++

/**
* @file utils/ref_count.hpp
* @author Martin Pulec <pulec@cesnet.cz>
*/
/*
* Copyright (c) 2022 CESNET z.s.p.o.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, is permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of CESNET nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef UTILS_REF_COUNT_H_0FC2C86B_8E95_45EF_AADE_F0A5C4ECBC31
#define UTILS_REF_COUNT_H_0FC2C86B_8E95_45EF_AADE_F0A5C4ECBC31
#include <optional>
template<typename T> struct ref_count_init_once {
std::optional<T> operator()(T (*init)(void), int &i) {
if (i++ == 0) {
return std::optional<T>(init());
}
return std::nullopt;
}
};
struct ref_count_terminate_last {
void operator()(void (*terminate)(void), int &i) {
if (--i == 0) {
terminate();
}
}
};
#endif // defined UTILS_REF_COUNT_H_0FC2C86B_8E95_45EF_AADE_F0A5C4ECBC31