threadpool

include/util/threadpool.h

@@ -9,13 +9,44 @@
 
 #include <thread>
 #include <mutex>
+#include <functional>
+#include <queue>
 
 namespace blt {
     
+    class runnable {
+        public:
+            virtual void run() = 0;
+            virtual ~runnable() = default;
+    };
+    
+    /**
+     * If your runnable functions are small consider using another data structure,
+     * as thread_pool will be slow if many small tasks are needed to be ran.
+     * thread_pool is designed for running large long run tasks
+     */
     class thread_pool {
         private:
-        
+            volatile bool halted;
+            int MAX_THREADS;
+            std::queue<runnable*> runQueue {};
+            std::vector<std::thread*> threads {};
+            std::mutex queueMutex {};
         public:
+            explicit thread_pool(int maxThreads);
+            
+            /**
+             * Attempts to start the thread_pool.
+             */
+            void start();
+            
+            void run(std::function<void()>& func);
+            
+            void run(runnable* func);
+            
+            void stop();
+            
+            ~thread_pool();
     };
     
 }

src/util/threadpool.cpp

@@ -4,3 +4,75 @@
  * See LICENSE file for license detail
  */
 #include <util/threadpool.h>
+
+class runnable_function : public blt::runnable {
+    private:
+        std::function<void()>& func;
+    public:
+        explicit runnable_function(std::function<void()>& func): func(func) {}
+        
+        void run() final {
+            func();
+        }
+};
+
+blt::thread_pool::thread_pool(int maxThreads): MAX_THREADS(maxThreads) {
+    halted = false;
+}
+
+blt::thread_pool::~thread_pool() {
+    stop();
+}
+
+void blt::thread_pool::start() {
+    for (int i = 0; i < MAX_THREADS; i++) {
+        threads.push_back(
+                new std::thread(
+                        [this]() -> void {
+                            while (!halted){
+                                // acquire a resource from the runnable queue
+                                std::unique_lock<std::mutex> lock(queueMutex);
+                                runnable* run = runQueue.front();
+                                runQueue.pop();
+                                lock.unlock();
+                                
+                                // attempt to run the function
+                                run->run();
+                                
+                                delete(run);
+                            }
+                        }
+                ));
+    }
+}
+
+void blt::thread_pool::stop() {
+    if (halted)
+        return;
+    
+    halted = true;
+    
+    for (std::thread* thread : threads)
+        thread->join();
+    
+    for (std::thread* thread : threads)
+        delete thread;
+    
+    std::scoped_lock<std::mutex> lock(queueMutex);
+    while (!runQueue.empty()){
+        delete runQueue.front();
+        runQueue.pop();
+    }
+}
+
+void blt::thread_pool::run(std::function<void()>& func) {
+    std::scoped_lock<std::mutex> lock(queueMutex);
+    runQueue.push(new runnable_function(func));
+}
+
+void blt::thread_pool::run(blt::runnable* func) {
+    std::scoped_lock<std::mutex> lock(queueMutex);
+    runQueue.push(func)
+}
+
+