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/* IBM_PROLOG_BEGIN_TAG */
/* This is an automatically generated prolog. */
/* */
/* $Source: src/include/util/impl/shared_ptr.H $ */
/* */
/* OpenPOWER HostBoot Project */
/* */
/* Contributors Listed Below - COPYRIGHT 2015 */
/* [+] International Business Machines Corp. */
/* */
/* */
/* Licensed under the Apache License, Version 2.0 (the "License"); */
/* you may not use this file except in compliance with the License. */
/* You may obtain a copy of the License at */
/* */
/* http://www.apache.org/licenses/LICENSE-2.0 */
/* */
/* Unless required by applicable law or agreed to in writing, software */
/* distributed under the License is distributed on an "AS IS" BASIS, */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or */
/* implied. See the License for the specific language governing */
/* permissions and limitations under the License. */
/* */
/* IBM_PROLOG_END_TAG */
#ifndef __UTIL_IMPL_SHARED_PTR_H
#define __UTIL_IMPL_SHARED_PTR_H
#include <cstddef>
#include <utility>
#include <stdint.h>
namespace std
{
namespace __impl
{
class shared_ptr_count
{
public:
shared_ptr_count() : count(1) {};
~shared_ptr_count() = default;
void increment() { __sync_add_and_fetch(&count, 1); };
bool decrement()
{ return 0 == __sync_add_and_fetch(&count, -1); };
size_t use_count() { return count; };
private:
size_t count;
};
}
template <typename T>
class shared_ptr
{
public:
typedef T element_type;
constexpr shared_ptr() :
count(nullptr), pointer(nullptr), owner(nullptr) {};
constexpr shared_ptr(nullptr_t) :
count(nullptr), pointer(nullptr), owner(nullptr) {};
template<typename U> explicit shared_ptr(U* ptr)
{
_setup(ptr);
}
template<typename U> shared_ptr(const shared_ptr<U>& r, T* ptr)
{ _copy(r); pointer = ptr; }
shared_ptr(const shared_ptr& r) { _copy(r); }
template<typename U> shared_ptr(const shared_ptr<U>& r)
{ _copy(r); }
shared_ptr(shared_ptr&& r) { _swap(std::move(r)); }
template<typename U> shared_ptr(shared_ptr<U>&& r)
{ _swap(std::move(r)); }
~shared_ptr() { _cleanup(); }
shared_ptr& operator=(const shared_ptr& r)
{
_cleanup();
_copy(r);
return *this;
}
template<typename U> shared_ptr& operator=(const shared_ptr<U>& r)
{
_cleanup();
_copy(r);
return *this;
}
shared_ptr& operator=(shared_ptr&& r)
{
_cleanup();
_swap(std::move(r));
return *this;
}
template<typename U> shared_ptr& operator=(shared_ptr<U>&& r)
{
_cleanup();
_swap(std::move(r));
return *this;
}
void reset() { _cleanup(); }
template<typename U> void reset(U* ptr) { _cleanup(); _setup(ptr); }
void swap(shared_ptr& r)
{
T* tmp0 = r.owner;
T* tmp1 = r.pointer;
__impl::shared_ptr_count* tmp2 = r.count;
r.owner = owner;
r.pointer = pointer;
r.count = count;
owner = tmp0;
pointer = tmp1;
count = tmp2;
}
T* get() const { return pointer; }
T& operator*() const { return *pointer; }
T* operator->() const { return pointer; }
long use_count() const
{
if (count) return count->use_count();
return 0;
}
bool unique() const { return use_count() == 1; }
explicit operator bool() const { return nullptr != get(); }
template<typename U>
bool owner_before(const shared_ptr<U>& other) const
{
return (owner < other.owner);
}
template <typename U> friend class shared_ptr;
private:
__impl::shared_ptr_count* count;
T* pointer;
T* owner;
template<typename U> void _setup(U* ptr)
{
owner = pointer = static_cast<T*>(ptr);
if (pointer)
{
count = new __impl::shared_ptr_count();
}
else
{
count = nullptr;
}
}
void _cleanup()
{
if (!count) return;
if (count->decrement())
{
delete count;
count = nullptr;
delete owner;
owner = nullptr;
pointer = nullptr;
}
}
template<typename U> void _copy(const shared_ptr<U>& r)
{
if (r.count) r.count->increment();
count = r.count;
owner = static_cast<T*>(r.owner);
pointer = static_cast<T*>(r.pointer);
}
template<typename U> void _swap(shared_ptr<U>&& r)
{
count = r.count;
owner = r.owner;
pointer = r.pointer;
r.count = nullptr;
r.owner = nullptr;
r.pointer = nullptr;
}
};
template <typename T, typename... Args>
shared_ptr<T> make_shared( Args&&... args)
{
return shared_ptr<T>(new T(std::forward<Args>(args)...));
}
template <typename T, typename U>
shared_ptr<T> static_pointer_cast(const shared_ptr<U>& r)
{
return shared_ptr<T>(r,
static_cast<typename shared_ptr<T>::element_type*>(r.get()));
}
template <typename T, typename U>
shared_ptr<T> dynamic_pointer_cast(const shared_ptr<U>& r)
{
return shared_ptr<T>(r,
dynamic_cast<typename shared_ptr<T>::element_type*>(r.get()));
}
template <typename T, typename U>
shared_ptr<T> const_pointer_cast(const shared_ptr<U>& r)
{
return shared_ptr<T>(r,
const_cast<typename shared_ptr<T>::element_type*>(r.get()));
}
template <typename T>
void swap(shared_ptr<T>& l, shared_ptr<T>& r) { return l.swap(r); }
}
#endif
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