X-Git-Url: http://plrg.eecs.uci.edu/git/?p=model-checker.git;a=blobdiff_plain;f=schedule.cc;h=7a703abab8cc7e229f7218c85add8580c7f3ad53;hp=67b40ec88a809d5c2bff10e07787481a7d934566;hb=5236350c6c02c09a167a461fce69c581768f9c03;hpb=d279e84ed265af079ea035d5dff49183def2c144

diff --git a/schedule.cc b/schedule.cc
index 67b40ec..7a703ab 100644
--- a/schedule.cc
+++ b/schedule.cc
@@ -1,48 +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 *)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));
+			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);
 }
 
-Thread * Scheduler::next_thread(void)
+/**
+ * Remove a given Thread from the scheduler.
+ * @param t The Thread to remove
+ */
+void Scheduler::remove_thread(Thread *t)
 {
-	Thread *t = model->schedule_next_thread();
+	if (current == t)
+		current = NULL;
+	set_enabled(t, false);
+}
 
-	if (t != NULL) {
-		current = t;
-		readyList.remove(t);
-	} else if (readyList.empty()) {
-		t = NULL;
+/**
+ * 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)
+{
+	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);
+}
+
+/**
+ * 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 {
-		t = readyList.front();
-		current = t;
-		readyList.pop_front();
+		curr_thread_index = id_to_int(t->get_id());
 	}
 
+	current = t;
 	print();
-
 	return t;
 }
 
-Thread * Scheduler::get_current_thread(void)
+/**
+ * @return The currently-running Thread
+ */
+Thread * Scheduler::get_current_thread() const
 {
 	return current;
 }
 
-void Scheduler::print()
+/**
+ * Print debugging information about the current state of the scheduler. Only
+ * prints something if debugging is enabled.
+ */
+void Scheduler::print() const
 {
 	if (current)
-		printf("Current thread: %d\n", current->get_id());
+		DEBUG("Current thread: %d\n", current->get_id());
 	else
-		printf("No current thread\n");
-	printf("Num. threads in ready list: %ld\n", readyList.size());
-
-	std::list<Thread *>::iterator it;
-	for (it = readyList.begin(); it != readyList.end(); it++)
-		printf("In ready list: thread %d\n", (*it)->get_id());
+		DEBUG("No current thread\n");
 }