Update Arlib

arlib/thread/split-thr.cpp

@@ -0,0 +1,95 @@
+#include "thread.h"
+
+#ifdef ARLIB_THREAD
+namespace {
+
+//TODO: there is no procedure for destroying threads
+struct threadpool {
+	mutex lock;
+	
+	multievent* wake;
+	multievent* started;
+	uint32_t numthreads;
+	uint32_t numidle;
+	
+	//these vary between each piece of work
+	function<void(unsigned int id)> work;
+	uint32_t id;
+	multievent* done;
+};
+
+static struct threadpool * pool;
+
+void threadproc(struct threadpool * This)
+{
+	while (true)
+	{
+		This->wake->wait();
+		lock_decr(&This->numidle);
+		
+		function<void(unsigned int id)> work = This->work;
+		unsigned int id = lock_incr(&This->id);
+		multievent* done = This->done;
+		
+		This->started->signal();
+		work(id);
+		done->signal();
+		lock_incr(&This->numidle);
+	}
+}
+
+struct threadpool* pool_create()
+{
+	struct threadpool * pool = new threadpool;
+	
+	pool->wake=new multievent();
+	pool->started=new multievent();
+	pool->numthreads=0;
+	pool->numidle=0;
+	
+	return pool;
+}
+
+void pool_delete(struct threadpool* pool)
+{
+	delete pool->wake;
+	delete pool->started;
+	delete pool;
+}
+
+}
+
+void thread_split(unsigned int count, function<void(unsigned int id)> work)
+{
+	if (!count) return;
+	if (count==1)
+	{
+		work(0);
+		return;
+	}
+	struct threadpool * This = thread_once_undo(&pool, bind(pool_create), bind(pool_delete));
+	
+	This->lock.lock();
+	multievent* done=new multievent();
+	
+	This->work=work;
+	This->id=1;
+	This->done=done;
+	
+	while (lock_read(&This->numidle) < count-1)
+	{
+		This->numthreads++;
+		lock_incr(&This->numidle);
+		thread_create(bind_ptr(threadproc, This));
+	}
+	
+	This->wake->signal(count-1);
+	This->started->wait(count-1);
+	This->lock.unlock();
+	
+	work(0);
+	
+	done->wait(count-1);
+	delete done;
+}
+#endif