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/**
* Copyright (c) 2018 Cornell University.
*
* Author: Ted Yin <[email protected]>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is furnished to do
* so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef _SALTICIDAE_REF_H
#define _SALTICIDAE_REF_H
#include <atomic>
#include <functional>
namespace salticidae {
struct _RCCtl {
size_t ref_cnt;
size_t weak_cnt;
void add_ref() { ref_cnt++; }
void add_weak() { weak_cnt++; }
bool release_ref() {
if (--ref_cnt) return false;
if (weak_cnt) return true;
delete this;
return true;
}
void release_weak() {
if (--weak_cnt) return;
if (ref_cnt) return;
delete this;
}
size_t get_cnt() { return ref_cnt; }
_RCCtl(): ref_cnt(1), weak_cnt(0) {}
~_RCCtl() {}
};
struct _ARCCtl {
std::atomic_size_t ref_cnt;
std::atomic_size_t weak_cnt;
std::atomic_uint8_t dcnt;
void add_ref() { ref_cnt++; }
void add_weak() { weak_cnt++; }
bool release_ref() {
dcnt++;
if (--ref_cnt) { dcnt--; return false; }
if (weak_cnt) { dcnt--; return true; }
if (!--dcnt) delete this;
return true;
}
void release_weak() {
dcnt++;
if (--weak_cnt) { dcnt--; return; }
if (ref_cnt) { dcnt--; return; }
if (!--dcnt) delete this;
}
size_t get_cnt() { return ref_cnt.load(); }
_ARCCtl(): ref_cnt(1), weak_cnt(0), dcnt(0) {}
~_ARCCtl() {}
};
template<typename T, typename R> class RcObjBase;
template<typename T, typename R>
class WeakObjBase {
T *obj;
R *ctl;
void release() { if (ctl) ctl->release_weak(); }
public:
friend RcObjBase<T, R>;
friend std::hash<WeakObjBase<T, R>>;
WeakObjBase(): ctl(nullptr) {}
WeakObjBase &operator=(const WeakObjBase &other) {
release();
obj = other.obj;
if ((ctl = other.ctl))
ctl->add_weak();
return *this;
}
WeakObjBase(const WeakObjBase &other):
obj(other.obj), ctl(other.ctl) {
if (ctl) ctl->add_weak();
}
WeakObjBase(WeakObjBase &&other):
obj(other.obj), ctl(other.ctl) {
other.ctl = nullptr;
}
WeakObjBase(const RcObjBase<T, R> &other);
~WeakObjBase() { release(); }
};
template<typename T, typename R>
class RcObjBase {
T *obj;
R *ctl;
void release() {
if (ctl && ctl->release_ref())
delete obj;
}
public:
friend WeakObjBase<T, R>;
friend std::hash<RcObjBase<T, R>>;
template<typename T__, typename T_, typename R_>
friend RcObjBase<T__, R_> static_pointer_cast(const RcObjBase<T_, R_> &other);
template<typename T_, typename R_> friend class RcObjBase;
operator T*() const { return obj; }
T *operator->() const { return obj; }
RcObjBase(): obj(nullptr), ctl(nullptr) {}
RcObjBase(T *obj): obj(obj), ctl(new R()) {}
RcObjBase &operator=(const RcObjBase &other) {
release();
obj = other.obj;
if ((ctl = other.ctl))
ctl->add_ref();
return *this;
}
RcObjBase(const RcObjBase &other):
obj(other.obj), ctl(other.ctl) {
if (ctl) ctl->add_ref();
}
template<typename T_>
RcObjBase(const RcObjBase<T_, R> &other):
obj(other.obj), ctl(other.ctl) {
if (ctl) ctl->add_ref();
}
RcObjBase(RcObjBase &&other):
obj(other.obj), ctl(other.ctl) {
other.ctl = nullptr;
}
RcObjBase(const WeakObjBase<T, R> &other) {
if (other.ctl && other.ctl->ref_cnt)
{
obj = other.obj;
ctl = other.ctl;
ctl->add_ref();
}
else
{
obj = nullptr;
ctl = nullptr;
}
}
~RcObjBase() { release(); }
size_t get_cnt() const { return ctl ? ctl->get_cnt() : 0; }
};
template<typename T, typename T_, typename R>
RcObjBase<T, R> static_pointer_cast(const RcObjBase<T_, R> &other) {
RcObjBase<T, R> rc{};
rc.obj = static_cast<T *>(other.obj);
if ((rc.ctl = other.ctl))
rc.ctl->add_ref();
return std::move(rc);
}
template<typename T, typename R>
inline WeakObjBase<T, R>::WeakObjBase(const RcObjBase<T, R> &other):
obj(other.obj), ctl(other.ctl) {
if (ctl) ctl->add_weak();
}
template<typename T> using RcObj = RcObjBase<T, _RCCtl>;
template<typename T> using WeakObj = WeakObjBase<T, _RCCtl>;
template<typename T> using ArcObj = RcObjBase<T, _ARCCtl>;
template<typename T> using AweakObj = WeakObjBase<T, _ARCCtl>;
}
namespace std {
template<typename T, typename R>
struct hash<salticidae::RcObjBase<T, R>> {
size_t operator()(const salticidae::RcObjBase<T, R> &k) const {
return (size_t)k.obj;
}
};
}
#endif
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