X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=schedule.cc;h=b1b41c3d88d579a766d5cd45ccf26815bc551a1e;hb=12b1a10eeff58161619bafcfd8e288b3e2c76621;hp=13b640cd8e832b2cca826e5a4b68d66143bb854c;hpb=94c12b28e9afeed050f40c3d2d625fa0e22f0387;p=c11tester.git

diff --git a/schedule.cc b/schedule.cc
index 13b640cd..b1b41c3d 100644
--- a/schedule.cc
+++ b/schedule.cc
@@ -1,32 +1,125 @@
+#include <string.h>
+#include <stdlib.h>
+
 #include "threads.h"
 #include "schedule.h"
 #include "common.h"
 #include "model.h"
 
+/** Constructor */
+Scheduler::Scheduler() :
+	is_enabled(NULL),
+	enabled_len(0),
+	curr_thread_index(0),
+	current(NULL)
+{
+}
+
+void Scheduler::set_enabled(Thread *t, bool enabled_status) {
+	int threadid=id_to_int(t->get_id());
+	if (threadid>=enabled_len) {
+		bool *new_enabled = (bool *)snapshot_malloc(sizeof(bool) * (threadid + 1));
+		memset(&new_enabled[enabled_len], 0, (threadid+1-enabled_len)*sizeof(bool));
+		if (is_enabled != NULL) {
+			memcpy(new_enabled, is_enabled, enabled_len*sizeof(bool));
+			snapshot_free(is_enabled);
+		}
+		is_enabled=new_enabled;
+		enabled_len=threadid+1;
+	}
+	is_enabled[threadid]=enabled_status;
+}
+
+/**
+ * Add a Thread to the scheduler's ready list.
+ * @param t The Thread to add
+ */
 void Scheduler::add_thread(Thread *t)
 {
 	DEBUG("thread %d\n", t->get_id());
-	readyList.push_back(t);
+	set_enabled(t, true);
+}
+
+/**
+ * Remove a given Thread from the scheduler.
+ * @param t The Thread to remove
+ */
+void Scheduler::remove_thread(Thread *t)
+{
+	if (current == t)
+		current = NULL;
+	set_enabled(t, false);
 }
 
-Thread *Scheduler::next_thread(void)
+/**
+ * Prevent a Thread from being scheduled. The sleeping Thread should be
+ * re-awoken via Scheduler::wake.
+ * @param thread The Thread that should sleep
+ */
+void Scheduler::sleep(Thread *t)
 {
-	Thread *t = model->schedule_next_thread();
+	set_enabled(t, false);
+	t->set_state(THREAD_BLOCKED);
+}
+
+/**
+ * Wake a Thread up that was previously waiting (see Scheduler::wait)
+ * @param t The Thread to wake up
+ */
+void Scheduler::wake(Thread *t)
+{
+	set_enabled(t, true);
+	t->set_state(THREAD_READY);
+}
 
-	if (t != NULL) {
-		readyList.remove(t);
-		return t;
+/**
+ * Select a Thread. This implementation defaults to round-robin, if a
+ * thread is not already provided.
+ *
+ * @param t Thread to run, if chosen by an external entity (e.g.,
+ * ModelChecker). May be NULL to indicate no external choice.
+ * @return The next Thread to run
+ */
+Thread * Scheduler::next_thread(Thread *t)
+{
+	if ( t == NULL ) {
+		int old_curr_thread = curr_thread_index;
+		while(true) {
+			curr_thread_index = (curr_thread_index+1) % enabled_len;
+			if (is_enabled[curr_thread_index]) {
+				t = model->get_thread(int_to_id(curr_thread_index));
+				break;
+			}
+			if (curr_thread_index == old_curr_thread) {
+				print();
+				return NULL;
+			}
+		}
+	} else {
+		curr_thread_index = id_to_int(t->get_id());
 	}
-	if (readyList.empty())
-		return NULL;
 
-	current = readyList.front();
-	readyList.pop_front();
+	current = t;
+	print();
+	return t;
+}
 
+/**
+ * @return The currently-running Thread
+ */
+Thread * Scheduler::get_current_thread() const
+{
 	return current;
 }
 
-Thread *Scheduler::get_current_thread(void)
+/**
+ * Print debugging information about the current state of the scheduler. Only
+ * prints something if debugging is enabled.
+ */
+void Scheduler::print() const
 {
-	return current;
+	if (current)
+		DEBUG("Current thread: %d\n", current->get_id());
+	else
+		DEBUG("No current thread\n");
 }