From 553db9c9a412bbb06cac2a952d776a1761caa5a1 Mon Sep 17 00:00:00 2001
From: rtrimana <rtrimana@uci.edu>
Date: Fri, 27 Jan 2017 16:12:47 -0800
Subject: [PATCH] Creating ConcurrentLinkedListQueue for C++

---
 .../iotrmi/C++/ConcurrentLinkedListQueue.cpp  | 175 ++++++++++++++++++
 .../iotrmi/C++/ConcurrentLinkedListQueue.hpp  |  48 +++++
 2 files changed, 223 insertions(+)
 create mode 100644 iotjava/iotrmi/C++/ConcurrentLinkedListQueue.cpp
 create mode 100644 iotjava/iotrmi/C++/ConcurrentLinkedListQueue.hpp

diff --git a/iotjava/iotrmi/C++/ConcurrentLinkedListQueue.cpp b/iotjava/iotrmi/C++/ConcurrentLinkedListQueue.cpp
new file mode 100644
index 0000000..3fd0273
--- /dev/null
+++ b/iotjava/iotrmi/C++/ConcurrentLinkedListQueue.cpp
@@ -0,0 +1,175 @@
+#include <iostream>
+#include <thread>
+
+#include "ConcurrentLinkedListQueue.hpp"
+
+using namespace std;
+
+
+Node::Node(void* val) {
+
+	value = val;
+	next = NULL;
+}
+
+
+Node::~Node() {
+
+	/*if (next != NULL) {
+		delete next;
+		next = NULL;
+	}
+	if (value != NULL) {
+		delete value;
+		value = NULL;
+	}*/
+}
+
+
+void* Node::getValue() {
+
+	return value;
+}
+
+
+Node* Node::getNext() {
+
+	return next;
+}
+
+
+void Node::setNext(Node* nxt) {
+
+	next = nxt;
+}
+
+
+ConcurrentLinkedListQueue::ConcurrentLinkedListQueue() {
+
+	tail = NULL;
+	head = NULL;
+}
+
+
+ConcurrentLinkedListQueue::~ConcurrentLinkedListQueue() {
+
+	void* val = NULL;
+	do {	// Dequeue and free everything up
+		val = dequeue();
+	} while(val != NULL);
+}
+
+
+void ConcurrentLinkedListQueue::enqueue(void* value) {
+
+	lock_guard<mutex> guard(mtx);
+	if (tail == NULL && head == NULL) {	// first element
+		tail = new Node(value);
+		head = tail;	// Both tail and head point to the first element
+	} else {	// Next elements
+		Node* newEl = new Node(value);
+		tail->setNext(newEl);
+		tail = newEl;
+	}
+}
+
+
+// Return element and remove from list
+void* ConcurrentLinkedListQueue::dequeue() {
+
+	lock_guard<mutex> guard(mtx);
+	if (tail == NULL && head == NULL) {	// empty
+		return NULL;
+	} else {
+		Node* retEl = head;
+		if (head->getNext() == NULL) {
+			head = NULL;
+			tail = NULL;
+		} else
+			head = head->getNext();
+		void* retVal = retEl->getValue();
+		// Prepare retEl for deletion
+		retEl->setNext(NULL);
+		delete retEl;
+		// Return just the value
+		return retVal;
+	}
+}
+
+
+void enQ(ConcurrentLinkedListQueue* methodQueue, char** test) {
+
+	/*char* test = new char[3];
+	test[0] = 'a';
+	test[1] = 'b';
+	test[2] = 'c';*/
+	void* ptr = test;
+	for(int i=0; i<10; i++ ) {
+		cout << "Enqueuing: " << test << " address: " << ptr << endl;
+		methodQueue->enqueue(ptr);
+	}
+}
+
+
+void deQ(ConcurrentLinkedListQueue* methodQueue) {
+
+	for(int i=0; i<12; i++) {
+		void* result = methodQueue->dequeue();
+		if (result != NULL) {
+			cout << "Dequeue result: " << result << endl;
+			cout << "Dequeue result: " << *((char**) result) << endl;		
+		} else {
+			cout << "Result is NULL!!! End of queue!" << endl;
+		}
+	}
+}
+
+
+int main(int argc, char *argv[])
+{
+	ConcurrentLinkedListQueue* methodQueue = new ConcurrentLinkedListQueue();
+	/*cout << "Dequeue result: " << methodQueue->dequeue() << endl;
+	string str = "this is a test string";
+	const char* test = str.c_str();
+	const char** test2 = &test;
+	cout << "Initial result: " << test << endl;
+	cout << "Initial result 2: " << *test2 << endl;
+	void* ptr = &test;
+	cout << "Pointer: " << ptr << endl;
+	methodQueue->enqueue(ptr);
+	methodQueue->enqueue(ptr);
+	void* result = methodQueue->dequeue();
+	cout << "Result: " << result << endl;
+	cout << "Dequeue result: " << *((const char**) result) << endl;
+	void* result2 = methodQueue->dequeue();
+	cout << "Dequeue result: " << *((const char**) result2) << endl;
+	void* result3 = methodQueue->dequeue();
+	cout << "Dequeue result: " << result3 << endl;*/
+	//thread t1,t2;
+
+	//t1 = thread(enQ, methodQueue);
+	//t2 = thread(deQ, methodQueue);
+
+	//t1.join();
+	//t2.join();
+
+	char* test = new char[3];
+	test[0] = 'a';
+	test[1] = 'b';
+	test[2] = 'c';
+	void* ptr = &test;
+	methodQueue->enqueue(ptr);
+	void* result = methodQueue->dequeue();
+	cout << "Dequeue result: " << *((char**) result) << endl;
+
+	thread t1,t2;
+
+	t1 = thread(enQ, methodQueue, &test);
+	t2 = thread(deQ, methodQueue);
+
+	t1.join();
+	t2.join();
+
+	return 0;
+}
+
diff --git a/iotjava/iotrmi/C++/ConcurrentLinkedListQueue.hpp b/iotjava/iotrmi/C++/ConcurrentLinkedListQueue.hpp
new file mode 100644
index 0000000..e18e5e4
--- /dev/null
+++ b/iotjava/iotrmi/C++/ConcurrentLinkedListQueue.hpp
@@ -0,0 +1,48 @@
+#ifndef _CONCURRENTLINKEDLISTQUEUE_HPP__
+#define _CONCURRENTLINKEDLISTQUEUE_HPP__
+#include <iostream>
+#include <mutex>
+
+/** Class ConcurrentLinkedListQueue is a queue that can handle
+ *  concurrent requests and packets for IoT communication via socket.
+ *  <p>
+ *  It stores object through a void pointer.
+ *
+ * @author      Rahmadi Trimananda <rtrimana @ uci.edu>
+ * @version     1.0
+ * @since       2017-01-27
+ */
+
+using namespace std;
+
+mutex mtx;
+
+class Node {
+
+	private:
+		Node* next;
+		void* value;
+
+	public:
+		Node(void* val);
+		~Node();
+		void* getValue();
+		Node* getNext();
+		void setNext(Node* nxt);
+
+};
+
+
+class ConcurrentLinkedListQueue {
+
+	private:
+		Node* tail;
+		Node* head;
+
+	public:
+		ConcurrentLinkedListQueue();
+		~ConcurrentLinkedListQueue();
+		void enqueue(void* value);	// Enqueue to tail
+		void* dequeue();			// Dequeue from tail
+};
+#endif
-- 
2.34.1