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📄 algorithm.cpp(3.73 KB)
📄 any.cpp(933 B)
📄 atomic.cpp(7.67 KB)
📄 barrier.cpp(3.77 KB)
📄 bind.cpp(715 B)
📄 charconv.cpp(4.51 KB)
📄 chrono.cpp(4.94 KB)
📄 condition_variable.cpp(2.73 KB)
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📄 debug.cpp(13.37 KB)
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📄 future.cpp(6.21 KB)
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📄 ios.cpp(12.62 KB)
📄 iostream.cpp(5.66 KB)
📄 locale.cpp(189.52 KB)
📄 memory.cpp(6.15 KB)
📄 mutex.cpp(5.77 KB)
📄 mutex_destructor.cpp(1.44 KB)
📄 new.cpp(5.98 KB)
📄 optional.cpp(1.16 KB)
📄 random.cpp(3.98 KB)
📄 random_shuffle.cpp(1.26 KB)
📄 regex.cpp(8.22 KB)
📄 shared_mutex.cpp(2.86 KB)
📄 stdexcept.cpp(592 B)
📄 string.cpp(11.54 KB)
📄 strstream.cpp(8.46 KB)
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📄 system_error.cpp(6.88 KB)
📄 thread.cpp(5.42 KB)
📄 typeinfo.cpp(1.79 KB)
📄 utility.cpp(497 B)
📄 valarray.cpp(1.67 KB)
📄 variant.cpp(517 B)
📄 vector.cpp(529 B)

Editing: barrier.cpp

//===------------------------- barrier.cpp ---------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include <__config>

#ifndef _LIBCPP_HAS_NO_THREADS

#include <barrier>
#include <thread>

_LIBCPP_BEGIN_NAMESPACE_STD

#if !defined(_LIBCPP_HAS_NO_TREE_BARRIER) && (_LIBCPP_STD_VER > 11)

class __barrier_algorithm_base {
public:
    struct alignas(64) /* naturally-align the heap state */ __state_t
    {
        struct {
            __atomic_base<__barrier_phase_t> __phase = ATOMIC_VAR_INIT(0);
        } __tickets[64];
    };

ptrdiff_t&         __expected;
    unique_ptr<char[]> __state_allocation;
    __state_t*         __state;

_LIBCPP_HIDDEN
    __barrier_algorithm_base(ptrdiff_t& __expected)
        : __expected(__expected)
    {
        size_t const __count = (__expected + 1) >> 1;
        size_t const __size = sizeof(__state_t) * __count;
        size_t __allocation_size = __size + alignof(__state_t);
        __state_allocation = unique_ptr<char[]>(new char[__allocation_size]);
        void* __allocation = __state_allocation.get();
        void* const __state_ = align(alignof(__state_t), __size, __allocation, __allocation_size);
        __state = new (__state_) __barrier_algorithm_base::__state_t[__count];
    }
    _LIBCPP_HIDDEN
    bool __arrive(__barrier_phase_t __old_phase)
    {
        __barrier_phase_t const __half_step = __old_phase + 1,
                                __full_step = __old_phase + 2;
        size_t __current_expected = __expected,
            __current = hash<thread::id>()(this_thread::get_id()) % ((__expected + 1) >> 1);
        for(int __round = 0;; ++__round) {
            if(__current_expected <= 1)
                return true;
            size_t const __end_node = ((__current_expected + 1) >> 1),
                         __last_node = __end_node - 1;
            for(;;++__current) {
                if(__current == __end_node)
                __current = 0;
                __barrier_phase_t expect = __old_phase;
                if(__current == __last_node && (__current_expected & 1))
                {
                    if(__state[__current].__tickets[__round].__phase.compare_exchange_strong(expect, __full_step, memory_order_acq_rel))
                        break;    // I'm 1 in 1, go to next __round
                }
                else if(__state[__current].__tickets[__round].__phase.compare_exchange_strong(expect, __half_step, memory_order_acq_rel))
                {
                    return false; // I'm 1 in 2, done with arrival
                }
                else if(expect == __half_step)
                {
                    if(__state[__current].__tickets[__round].__phase.compare_exchange_strong(expect, __full_step, memory_order_acq_rel))
                        break;    // I'm 2 in 2, go to next __round
                }
            }
            __current_expected = __last_node + 1;
            __current >>= 1;
        }
    }
};

_LIBCPP_EXPORTED_FROM_ABI
__barrier_algorithm_base * __construct_barrier_algorithm_base(ptrdiff_t& __expected)
{
    return new __barrier_algorithm_base(__expected);
}
_LIBCPP_EXPORTED_FROM_ABI
bool __arrive_barrier_algorithm_base(__barrier_algorithm_base* __barrier,
                                     __barrier_phase_t __old_phase)
{
    return __barrier->__arrive(__old_phase);
}
_LIBCPP_EXPORTED_FROM_ABI
void __destroy_barrier_algorithm_base(__barrier_algorithm_base* __barrier)
{
    delete __barrier;
}

#endif //!defined(_LIBCPP_HAS_NO_TREE_BARRIER) && (_LIBCPP_STD_VER >= 11)

_LIBCPP_END_NAMESPACE_STD

#endif //_LIBCPP_HAS_NO_THREADS

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Editing: barrier.cpp

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