add threadpool implementation

src/util/threadpool.cpp

@@ -0,0 +1,51 @@
+#include <llmr/util/threadpool.hpp>
+
+using namespace llmr::util;
+
+Threadpool::Threadpool(Callback callback, int max_workers)
+    : max_workers(max_workers),
+      callback(callback) {
+}
+
+void Threadpool::add(void *data) {
+    if (worker_count < max_workers) {
+        workers.emplace_front(*this);
+        worker_count++;
+    }
+
+    pthread_mutex_lock(&mutex);
+    tasks.push(data);
+    pthread_mutex_unlock(&mutex);
+    pthread_cond_signal(&condition);
+}
+
+Threadpool::Worker::Worker(Threadpool& pool)
+    : pool(pool) {
+    pthread_create(&thread, nullptr, loop, (void *)this);
+}
+
+Threadpool::Worker::~Worker() {
+    pthread_cancel(thread);
+}
+
+
+void *Threadpool::Worker::loop(void *ptr) {
+    Worker *worker = static_cast<Worker *>(ptr);
+    Threadpool& pool = worker->pool;
+
+    pthread_setname_np("worker");
+    pthread_mutex_lock(&pool.mutex);
+    while (true) {
+        if (pool.tasks.size()) {
+            void *task = pool.tasks.front();
+            pool.tasks.pop();
+            pthread_mutex_unlock(&pool.mutex);
+            pool.callback(task);
+            pthread_mutex_lock(&pool.mutex);
+        } else {
+            pthread_cond_wait(&pool.condition, &pool.mutex);
+        }
+    }
+
+    return nullptr;
+}