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// Support for atomic operations -*- C++ -*-

// Copyright (C) 2008, 2009

// Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the

// terms of the GNU General Public License as published by the

// Free Software Foundation; either version 3, or (at your option)

// any later version.

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional

// permissions described in the GCC Runtime Library Exception, version

// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and

// a copy of the GCC Runtime Library Exception along with this program;

// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see

// <http://www.gnu.org/licenses/>.

#include "gstdint.h"

#include <atomic>

#include <mutex>

#define LOGSIZE 4

namespace

{

#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)

  std::mutex&

  get_atomic_mutex()

  {

    static std::mutex atomic_mutex;

    return atomic_mutex;

  }

#endif

  std::__atomic_flag_base flag_table[ 1 << LOGSIZE ] =

    {

      ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,

      ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,

      ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,

      ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT, ATOMIC_FLAG_INIT,

    };

} // anonymous namespace

namespace std

{

  namespace __atomic0

  {

    bool

    atomic_flag::test_and_set(memory_order)

    {

#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)

      lock_guard<mutex> __lock(get_atomic_mutex());

#endif

      bool result = _M_i;

      _M_i = true;

      return result;

    }

    void

    atomic_flag::clear(memory_order)

    {

#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)

      lock_guard<mutex> __lock(get_atomic_mutex());

#endif

      _M_i = false;

    }

  }

  extern "C"

  {

    bool

    atomic_flag_test_and_set_explicit(__atomic_flag_base* __a,

                                      memory_order __m) throw()

    {

      atomic_flag* d = static_cast<volatile atomic_flag*>(__a);

      return d->test_and_set(__m);

    }

    void

    atomic_flag_clear_explicit(__atomic_flag_base* __a,

                               memory_order __m) throw()

    {

      atomic_flag* d = static_cast<volatile atomic_flag*>(__a);

      return d->clear(__m);

    }

    void

    __atomic_flag_wait_explicit(__atomic_flag_base* __a,

                                memory_order __x) throw()

    {

      while (atomic_flag_test_and_set_explicit(__a, __x))

        { };

    }

    __atomic_flag_base*

    __atomic_flag_for_address(const void* __z) throw()

    {

      uintptr_t __u = reinterpret_cast<uintptr_t>(__z);

      __u += (__u >> 2) + (__u << 4);

      __u += (__u >> 7) + (__u << 5);

      __u += (__u >> 17) + (__u << 13);

      if (sizeof(uintptr_t) > 4)

        __u += (__u >> 31);

      __u &= ~((~uintptr_t(0)) << LOGSIZE);

      return flag_table + __u;

    }

  } // extern "C"

} // namespace std

// XXX GLIBCXX_ABI Deprecated

// gcc-4.5.0

// <atomic> signature changes

// The rename syntax for default exported names is

//   asm (".symver name1,exportedname@GLIBCXX_3.4")

//   asm (".symver name2,exportedname@@GLIBCXX_3.4.5")

// In the future, GLIBCXX_ABI > 6 should remove all uses of

// _GLIBCXX_*_SYMVER macros in this file.

#if defined(_GLIBCXX_SYMVER_GNU) && defined(PIC) \

    && defined(_GLIBCXX_HAVE_AS_SYMVER_DIRECTIVE)

#define _GLIBCXX_ASM_SYMVER(cur, old, version) \

   asm (".symver " #cur "," #old "@@" #version);

_GLIBCXX_ASM_SYMVER(_ZNSt9__atomic011atomic_flag5clearESt12memory_order, _ZNVSt9__atomic011atomic_flag5clearESt12memory_order, GLIBCXX_3.4.11)

_GLIBCXX_ASM_SYMVER(_ZNSt9__atomic011atomic_flag12test_and_setESt12memory_order, _ZNVSt9__atomic011atomic_flag12test_and_setESt12memory_order, GLIBCXX_3.4.11)

#endif