osonceflag.h

/******************************************************************************
 
    @file    IntrOS: osonceflag.h
    @author  Rajmund Szymanski
    @date    17.11.2025
    @brief   This file contains definitions for IntrOS.
 
 ******************************************************************************
 
   Copyright (c) 2018-2022 Rajmund Szymanski. All rights reserved.
 
   Permission is hereby granted, free of charge, to any person obtaining a copy
   of this software and associated documentation files (the "Software"), to
   deal in the Software without restriction, including without limitation the
   rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
   sell copies of the Software, and to permit persons to whom the Software is
   furnished to do so, subject to the following conditions:
 
   The above copyright notice and this permission notice shall be included
   in all copies or substantial portions of the Software.
 
   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
   THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
   IN THE SOFTWARE.
 
 ******************************************************************************/
 
#ifndef __INTROS_ONE_H
#define __INTROS_ONE_H
 
#include "oskernel.h"
#include "oscriticalsection.h"


 
typedef uint_fast8_t one_t;
typedef uint_fast8_t one_id [];
 
/******************************************************************************
 *
 * Name              : _ONE_INIT
 *
 * Description       : once flag state after initialization
 *
 * Parameters        : none
 *
 * Return            : once flag object
 *
 * Note              : for internal use
 *
 ******************************************************************************/
 
#define               _ONE_INIT()   0
 
/******************************************************************************
 *
 * Name              : _ONE_DONE
 *
 * Description       : once flag state after use
 *
 * Parameters        : none
 *
 * Return            : once flag object
 *
 * Note              : for internal use
 *
 ******************************************************************************/
 
#define               _ONE_DONE()   1

 
#define             OS_ONE( one ) \
                       one_t one[] = { _ONE_INIT() }

/** static alias of OS_ONE() */
#define         static_ONE( one ) \
                static one_t one[] = { _ONE_INIT() }

 
#ifndef __cplusplus
#define                ONE_INIT() \
                      _ONE_INIT()
#endif

 
#ifndef __cplusplus
#define                ONE_CREATE() \
                     { ONE_INIT  () }
/** alias of ONE_CREATE() */
#define                ONE_NEW \
                       ONE_CREATE
#endif
 
#ifdef __cplusplus
extern "C" {
#endif

 
__STATIC_INLINE
void one_init( one_t *one ) { *one = 0; }

 
__STATIC_INLINE
void one_call( one_t *one, fun_t *fun )
{
    one_t flag;
    assert(one);
    assert(fun);
#if OS_ATOMICS
    flag = __STD atomic_exchange((__STD atomic_uint_fast8_t *)one, _ONE_DONE());
#else
    sys_lock(); flag = *one; *one = _ONE_DONE(); sys_unlock();
#endif
    if (flag == _ONE_INIT()) fun();
}
 
#ifdef __cplusplus
}
#endif
 
/* -------------------------------------------------------------------------- */
 
#if defined(__cplusplus)
namespace intros {

 
struct OnceFlag
{
    constexpr
    OnceFlag(): flg_{_ONE_INIT()} {}

    OnceFlag( OnceFlag&& ) = default;
    OnceFlag( const OnceFlag& ) = delete;
    OnceFlag& operator=( OnceFlag&& ) = delete;
    OnceFlag& operator=( const OnceFlag& ) = delete;
 
#if __cplusplus >= 201402L
    template<typename Callable, typename... Args>
    void call( Callable&& _fun, Args&&... _args )
    {
        one_t flag;
    #if OS_ATOMICS
        flag = std::atomic_exchange((std::atomic_uint_fast8_t *)&flg_, _ONE_DONE());
    #else
        { CriticalSection cri; flag = flg_; flg_ = _ONE_DONE(); }
    #endif
        if (flag == _ONE_INIT()) _fun(std::forward<Args>(_args)...);
    }
#else
    void call( fun_t *_fun )
    {
        one_call(&flg_, _fun);
    }
#endif
 
    private:
    one_t flg_;
};
 
}     //  namespace
#endif//__cplusplus
 
/* -------------------------------------------------------------------------- */

 
#endif//__INTROS_ONE_H