Changes between Initial Version and Version 1 of examples_from_lect3

Timestamp:

01/22/16 13:33:47 (8 years ago)

Author:

Evgeny Linsky

Comment:

--

examples_from_lect3

@@ +1 @@
+{{{
+#ifndef _SHAREDPTR_H_
+#define _SHAREDPTR_H_
+
+#include "GaussNumber.h"
+#define NULL 0
+
+class Storage {
+
+private:
+        GaussNumber *p_obj;
+        int count;
+
+public:
+        Storage(GaussNumber *p_obj);
+        ~Storage();
+        void increaseCount();
+        void decreaseCount();
+        GaussNumber *ptr() const;
+        bool isNull() const;
+
+};
+
+
+class shared_ptr {
+
+private:
+        Storage *storage;
+
+public:
+        shared_ptr();
+        shared_ptr(GaussNumber *p_obj);
+        shared_ptr(const shared_ptr &sptr);
+        ~shared_ptr();
+        const shared_ptr &operator=(const shared_ptr &sptr);
+        GaussNumber &operator*() const;
+        GaussNumber *operator->() const;
+        GaussNumber *ptr() const;
+        bool isNull() const;
+
+};
+
+#endif
+}}}
+
+{{{
+#include "shared_ptr.h"
+
+// Storage class definitions
+
+Storage::Storage(GaussNumber *p_obj) {
+        this->p_obj = p_obj;
+        count = 1;
+}
+
+Storage::~Storage() {
+        if (p_obj != NULL)
+                delete p_obj;
+}
+
+void Storage::increaseCount() {
+        count++;
+}
+
+void Storage::decreaseCount() {
+        count--;
+
+        if (count == 0)
+                delete this;
+}
+
+GaussNumber *Storage::ptr() const {
+        return p_obj;
+}
+
+bool Storage::isNull() const {
+        if (p_obj == NULL)
+                return true;
+        else
+                return false;
+}
+
+// shared_ptr class definitions
+
+shared_ptr::shared_ptr() {
+        storage = new Storage(NULL);
+}
+
+shared_ptr::shared_ptr(GaussNumber *p_obj) {
+        storage = new Storage(p_obj);
+}
+
+shared_ptr::shared_ptr(const shared_ptr &sptr) {
+        storage = sptr.storage;
+        storage->increaseCount();
+}
+
+shared_ptr::~shared_ptr() {
+        storage->decreaseCount();
+}
+
+const shared_ptr &shared_ptr::operator=(const shared_ptr &sptr) {
+        sptr.storage->increaseCount();
+        storage->decreaseCount();
+        
+        storage = sptr.storage;
+        return *this;
+}
+
+GaussNumber &shared_ptr::operator*() const {
+        return *storage->ptr();
+}
+
+GaussNumber *shared_ptr::operator->() const {
+        return storage->ptr();
+}
+
+GaussNumber *shared_ptr::ptr() const {
+        return storage->ptr();
+}
+
+bool shared_ptr::isNull() const {
+        return storage->isNull();
+}
+}}}