X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=schedule.cc;h=cca60ebfba45795252c4e3de97d1223b934aa0f4;hb=8669bd6f88178382893b48223498611f2200714a;hp=69e3d88803bcc06d15ee2fed115330b1397662f5;hpb=1f89a2b5691c26417c93d283e73e181bc6cea1a5;p=model-checker.git

diff --git a/schedule.cc b/schedule.cc
index 69e3d88..cca60eb 100644
--- a/schedule.cc
+++ b/schedule.cc
@@ -1,3 +1,6 @@
+#include <string.h>
+#include <stdlib.h>
+
 #include "threads.h"
 #include "schedule.h"
 #include "common.h"
@@ -5,18 +8,47 @@
 
 /** Constructor */
 Scheduler::Scheduler() :
+	enabled(NULL),
+	enabled_len(0),
+	curr_thread_index(0),
 	current(NULL)
 {
 }
 
+void Scheduler::set_enabled(Thread *t, enabled_type_t enabled_status) {
+	int threadid=id_to_int(t->get_id());
+	if (threadid>=enabled_len) {
+		enabled_type_t *new_enabled = (enabled_type_t *)snapshot_malloc(sizeof(enabled_type_t) * (threadid + 1));
+		memset(&new_enabled[enabled_len], 0, (threadid+1-enabled_len)*sizeof(enabled_type_t));
+		if (enabled != NULL) {
+			memcpy(new_enabled, enabled, enabled_len*sizeof(enabled_type_t));
+			snapshot_free(enabled);
+		}
+		enabled=new_enabled;
+		enabled_len=threadid+1;
+	}
+	enabled[threadid]=enabled_status;
+}
+
+/**
+ * @brief Check if a Thread is currently enabled
+ * @param t The Thread to check
+ * @return True if the Thread is currently enabled
+ */
+bool Scheduler::is_enabled(Thread *t) const
+{
+	int id = id_to_int(t->get_id());
+	return (id >= enabled_len) ? false : (enabled[id] == THREAD_ENABLED);
+}
+
 /**
  * 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);
+	DEBUG("thread %d\n", id_to_int(t->get_id()));
+	set_enabled(t, THREAD_ENABLED);
 }
 
 /**
@@ -27,31 +59,59 @@ void Scheduler::remove_thread(Thread *t)
 {
 	if (current == t)
 		current = NULL;
-	else
-		readyList.remove(t);
+	set_enabled(t, THREAD_DISABLED);
 }
 
 /**
- * Remove one Thread from the scheduler. This implementation performs FIFO.
- * @return The next Thread to run
+ * Prevent a Thread from being scheduled. The sleeping Thread should be
+ * re-awoken via Scheduler::wake.
+ * @param thread The Thread that should sleep
  */
-Thread * Scheduler::next_thread()
+void Scheduler::sleep(Thread *t)
 {
-	Thread *t = model->schedule_next_thread();
+	set_enabled(t, THREAD_DISABLED);
+	t->set_state(THREAD_BLOCKED);
+}
 
-	if (t != NULL) {
-		current = t;
-		readyList.remove(t);
-	} else if (readyList.empty()) {
-		t = NULL;
+/**
+ * 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, THREAD_DISABLED);
+	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 (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;
 }
 
@@ -70,12 +130,7 @@ Thread * Scheduler::get_current_thread() const
 void Scheduler::print() const
 {
 	if (current)
-		DEBUG("Current thread: %d\n", current->get_id());
+		DEBUG("Current thread: %d\n", id_to_int(current->get_id()));
 	else
 		DEBUG("No current thread\n");
-	DEBUG("Num. threads in ready list: %zu\n", readyList.size());
-
-	std::list<Thread *, MyAlloc< Thread * > >::const_iterator it;
-	for (it = readyList.begin(); it != readyList.end(); it++)
-		DEBUG("In ready list: thread %d\n", (*it)->get_id());
 }