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1 files changed, 202 insertions, 0 deletions

diff --git a/include/salticidae/ref.h b/include/salticidae/ref.h
new file mode 100644
index 0000000..5f54da2
--- /dev/null
+++ b/include/salticidae/ref.h
@@ -0,0 +1,202 @@
+/**
+ * Copyright (c) 2018 Cornell University.
+ *
+ * Author: Ted Yin <tederminant@gmail.com>
+ *
+ * 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 {
+    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();
+        ctl = other.ctl;
+        ctl->add_weak();
+        return *this;
+    }
+
+    WeakObjBase(const WeakObjBase &other): ctl(other.ctl) {
+        ctl->add_weak();
+    }
+
+    WeakObjBase(WeakObjBase &&other): 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;
+        ctl = other.ctl;
+        ctl->add_ref();
+        return *this;
+    }
+
+    RcObjBase(const RcObjBase &other):
+            obj(other.obj), ctl(other.ctl) {
+        ctl->add_ref();
+    }
+
+    template<typename T_>
+    RcObjBase(const RcObjBase<T_, R> &other):
+            obj(other.obj), ctl(other.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);
+    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):
+        ctl(other.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