ceph/src/boost/libs/atomic/include/boost/atomic/detail/ops_emulated.hpp

   1 /*
   2  * Distributed under the Boost Software License, Version 1.0.
   3  * (See accompanying file LICENSE_1_0.txt or copy at
   4  * http://www.boost.org/LICENSE_1_0.txt)
   5  *
   6  * Copyright (c) 2014 Andrey Semashev
   7  */
   8 /*!
   9  * \file   atomic/detail/ops_emulated.hpp
  10  *
  11  * This header contains lockpool-based implementation of the \c operations template.
  12  */
  13
  14 #ifndef BOOST_ATOMIC_DETAIL_OPS_EMULATED_HPP_INCLUDED_
  15 #define BOOST_ATOMIC_DETAIL_OPS_EMULATED_HPP_INCLUDED_
  16
  17 #include <cstddef>
  18 #include <boost/memory_order.hpp>
  19 #include <boost/atomic/detail/config.hpp>
  20 #include <boost/atomic/detail/storage_type.hpp>
  21 #include <boost/atomic/detail/operations_fwd.hpp>
  22 #include <boost/atomic/detail/lockpool.hpp>
  23 #include <boost/atomic/capabilities.hpp>
  24
  25 #ifdef BOOST_HAS_PRAGMA_ONCE
  26 #pragma once
  27 #endif
  28
  29 namespace boost {
  30 namespace atomics {
  31 namespace detail {
  32
  33 template< typename T >
  34 struct emulated_operations
  35 {
  36     typedef T storage_type;
  37
  38     static BOOST_CONSTEXPR_OR_CONST bool is_always_lock_free = false;
  39
  40     static BOOST_FORCEINLINE void store(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
  41     {
  42         lockpool::scoped_lock lock(&storage);
  43         const_cast< storage_type& >(storage) = v;
  44     }
  45
  46     static BOOST_FORCEINLINE storage_type load(storage_type const volatile& storage, memory_order) BOOST_NOEXCEPT
  47     {
  48         lockpool::scoped_lock lock(&storage);
  49         return const_cast< storage_type const& >(storage);
  50     }
  51
  52     static BOOST_FORCEINLINE storage_type fetch_add(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
  53     {
  54         storage_type& s = const_cast< storage_type& >(storage);
  55         lockpool::scoped_lock lock(&storage);
  56         storage_type old_val = s;
  57         s += v;
  58         return old_val;
  59     }
  60
  61     static BOOST_FORCEINLINE storage_type fetch_sub(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
  62     {
  63         storage_type& s = const_cast< storage_type& >(storage);
  64         lockpool::scoped_lock lock(&storage);
  65         storage_type old_val = s;
  66         s -= v;
  67         return old_val;
  68     }
  69
  70     static BOOST_FORCEINLINE storage_type exchange(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
  71     {
  72         storage_type& s = const_cast< storage_type& >(storage);
  73         lockpool::scoped_lock lock(&storage);
  74         storage_type old_val = s;
  75         s = v;
  76         return old_val;
  77     }
  78
  79     static BOOST_FORCEINLINE bool compare_exchange_strong(
  80         storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
  81     {
  82         storage_type& s = const_cast< storage_type& >(storage);
  83         lockpool::scoped_lock lock(&storage);
  84         storage_type old_val = s;
  85         const bool res = old_val == expected;
  86         if (res)
  87             s = desired;
  88         expected = old_val;
  89
  90         return res;
  91     }
  92
  93     static BOOST_FORCEINLINE bool compare_exchange_weak(
  94         storage_type volatile& storage, storage_type& expected, storage_type desired, memory_order, memory_order) BOOST_NOEXCEPT
  95     {
  96         // Note: This function is the exact copy of compare_exchange_strong. The reason we're not just forwarding the call
  97         // is that MSVC-12 ICEs in this case.
  98         storage_type& s = const_cast< storage_type& >(storage);
  99         lockpool::scoped_lock lock(&storage);
 100         storage_type old_val = s;
 101         const bool res = old_val == expected;
 102         if (res)
 103             s = desired;
 104         expected = old_val;
 105
 106         return res;
 107     }
 108
 109     static BOOST_FORCEINLINE storage_type fetch_and(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
 110     {
 111         storage_type& s = const_cast< storage_type& >(storage);
 112         lockpool::scoped_lock lock(&storage);
 113         storage_type old_val = s;
 114         s &= v;
 115         return old_val;
 116     }
 117
 118     static BOOST_FORCEINLINE storage_type fetch_or(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
 119     {
 120         storage_type& s = const_cast< storage_type& >(storage);
 121         lockpool::scoped_lock lock(&storage);
 122         storage_type old_val = s;
 123         s |= v;
 124         return old_val;
 125     }
 126
 127     static BOOST_FORCEINLINE storage_type fetch_xor(storage_type volatile& storage, storage_type v, memory_order) BOOST_NOEXCEPT
 128     {
 129         storage_type& s = const_cast< storage_type& >(storage);
 130         lockpool::scoped_lock lock(&storage);
 131         storage_type old_val = s;
 132         s ^= v;
 133         return old_val;
 134     }
 135
 136     static BOOST_FORCEINLINE bool test_and_set(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
 137     {
 138         return !!exchange(storage, (storage_type)1, order);
 139     }
 140
 141     static BOOST_FORCEINLINE void clear(storage_type volatile& storage, memory_order order) BOOST_NOEXCEPT
 142     {
 143         store(storage, (storage_type)0, order);
 144     }
 145
 146     static BOOST_FORCEINLINE bool is_lock_free(storage_type const volatile&) BOOST_NOEXCEPT
 147     {
 148         return false;
 149     }
 150 };
 151
 152 template< std::size_t Size, bool Signed >
 153 struct operations :
 154     public emulated_operations< typename make_storage_type< Size, Signed >::type >
 155 {
 156     typedef typename make_storage_type< Size, Signed >::aligned aligned_storage_type;
 157 };
 158
 159 } // namespace detail
 160 } // namespace atomics
 161 } // namespace boost
 162
 163 #endif // BOOST_ATOMIC_DETAIL_OPS_EMULATED_HPP_INCLUDED_