bitcore-node-zcash/deps/boost/atomic/detail/cas64strong-ptr.hpp

248 lines
6.7 KiB
C++

#ifndef BOOST_ATOMIC_DETAIL_CAS64STRONG_PTR_HPP
#define BOOST_ATOMIC_DETAIL_CAS64STRONG_PTR_HPP
// Distributed under the Boost Software License, Version 1.0.
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// Copyright (c) 2011 Helge Bahmann
// Copyright (c) 2013 Tim Blechmann
// Build 64-bit atomic operation on pointers from platform_cmpxchg64_strong
// primitive. It is assumed that 64-bit loads/stores are not
// atomic, so they are implemented through platform_load64/platform_store64.
//
// The reason for extracting pointer specializations to a separate header is
// that 64-bit CAS is available on some 32-bit platforms (notably, x86).
// On these platforms there is no need for 64-bit pointer specializations,
// since they will never be used.
#include <string.h>
#include <cstddef>
#include <boost/cstdint.hpp>
#include <boost/memory_order.hpp>
#include <boost/atomic/detail/config.hpp>
#include <boost/atomic/detail/base.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
namespace atomics {
namespace detail {
/* pointer types */
template<bool Sign>
class base_atomic<void *, void *, 8, Sign>
{
private:
typedef base_atomic this_type;
typedef void * value_type;
typedef std::ptrdiff_t difference_type;
protected:
typedef value_type value_arg_type;
public:
BOOST_DEFAULTED_FUNCTION(base_atomic(void), {})
BOOST_CONSTEXPR explicit base_atomic(value_type v) BOOST_NOEXCEPT : v_(v) {}
void
store(value_type v, memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
{
platform_fence_before_store(order);
platform_store64(v, &v_);
platform_fence_after_store(order);
}
value_type
load(memory_order order = memory_order_seq_cst) const volatile BOOST_NOEXCEPT
{
value_type v = platform_load64(&v_);
platform_fence_after_load(order);
return v;
}
value_type
exchange(value_type v, memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
{
value_type original = load(memory_order_relaxed);
do {
} while (!compare_exchange_weak(original, v, order, memory_order_relaxed));
return original;
}
bool
compare_exchange_weak(
value_type & expected,
value_type desired,
memory_order success_order,
memory_order failure_order) volatile BOOST_NOEXCEPT
{
return compare_exchange_strong(expected, desired, success_order, failure_order);
}
bool
compare_exchange_strong(
value_type & expected,
value_type desired,
memory_order success_order,
memory_order failure_order) volatile BOOST_NOEXCEPT
{
platform_fence_before(success_order);
bool success = platform_cmpxchg64_strong(expected, desired, &v_);
if (success) {
platform_fence_after(success_order);
} else {
platform_fence_after(failure_order);
}
return success;
}
value_type
fetch_add(difference_type v, memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
{
value_type original = load(memory_order_relaxed);
do {
} while (!compare_exchange_weak(original, (char*)original + v, order, memory_order_relaxed));
return original;
}
value_type
fetch_sub(difference_type v, memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
{
value_type original = load(memory_order_relaxed);
do {
} while (!compare_exchange_weak(original, (char*)original - v, order, memory_order_relaxed));
return original;
}
bool
is_lock_free(void) const volatile BOOST_NOEXCEPT
{
return true;
}
BOOST_ATOMIC_DECLARE_VOID_POINTER_OPERATORS
BOOST_DELETED_FUNCTION(base_atomic(base_atomic const&))
BOOST_DELETED_FUNCTION(base_atomic& operator=(base_atomic const&))
private:
value_type v_;
};
template<typename T, bool Sign>
class base_atomic<T *, void *, 8, Sign>
{
private:
typedef base_atomic this_type;
typedef T * value_type;
typedef std::ptrdiff_t difference_type;
protected:
typedef value_type value_arg_type;
public:
BOOST_DEFAULTED_FUNCTION(base_atomic(void), {})
BOOST_CONSTEXPR explicit base_atomic(value_type v) BOOST_NOEXCEPT : v_(v) {}
void
store(value_type v, memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
{
platform_fence_before_store(order);
platform_store64(v, &v_);
platform_fence_after_store(order);
}
value_type
load(memory_order order = memory_order_seq_cst) const volatile BOOST_NOEXCEPT
{
value_type v = platform_load64(&v_);
platform_fence_after_load(order);
return v;
}
value_type
exchange(value_type v, memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
{
value_type original = load(memory_order_relaxed);
do {
} while (!compare_exchange_weak(original, v, order, memory_order_relaxed));
return original;
}
bool
compare_exchange_weak(
value_type & expected,
value_type desired,
memory_order success_order,
memory_order failure_order) volatile BOOST_NOEXCEPT
{
return compare_exchange_strong(expected, desired, success_order, failure_order);
}
bool
compare_exchange_strong(
value_type & expected,
value_type desired,
memory_order success_order,
memory_order failure_order) volatile BOOST_NOEXCEPT
{
platform_fence_before(success_order);
bool success = platform_cmpxchg64_strong(expected, desired, &v_);
if (success) {
platform_fence_after(success_order);
} else {
platform_fence_after(failure_order);
}
return success;
}
value_type
fetch_add(difference_type v, memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
{
value_type original = load(memory_order_relaxed);
do {
} while (!compare_exchange_weak(original, original + v, order, memory_order_relaxed));
return original;
}
value_type
fetch_sub(difference_type v, memory_order order = memory_order_seq_cst) volatile BOOST_NOEXCEPT
{
value_type original = load(memory_order_relaxed);
do {
} while (!compare_exchange_weak(original, original - v, order, memory_order_relaxed));
return original;
}
bool
is_lock_free(void) const volatile BOOST_NOEXCEPT
{
return true;
}
BOOST_ATOMIC_DECLARE_POINTER_OPERATORS
BOOST_DELETED_FUNCTION(base_atomic(base_atomic const&))
BOOST_DELETED_FUNCTION(base_atomic& operator=(base_atomic const&))
private:
value_type v_;
};
}
}
}
#endif