Z3 sources

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

lib/sat_var_queue.h

@@ -0,0 +1,67 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    sat_var_queue.h
+
+Abstract:
+
+    SAT variable priority queue.
+
+Author:
+
+    Leonardo de Moura (leonardo) 2011-05-21.
+
+Revision History:
+
+--*/
+#ifndef _SAT_VAR_QUEUE_H_
+#define _SAT_VAR_QUEUE_H_
+
+#include"heap.h"
+#include"sat_types.h"
+
+namespace sat {
+    
+    class var_queue {
+        struct lt {
+            svector<unsigned> & m_activity;
+            lt(svector<unsigned> & act):m_activity(act) {}
+            bool operator()(bool_var v1, bool_var v2) const { return m_activity[v1] > m_activity[v2]; }
+        };
+        heap<lt>  m_queue;
+    public:
+        var_queue(svector<unsigned> & act):m_queue(128, lt(act)) {}
+        
+        void activity_increased_eh(bool_var v) {
+            if (m_queue.contains(v))
+                m_queue.decreased(v);
+        }
+
+        void mk_var_eh(bool_var v) {
+            m_queue.reserve(v+1);
+            m_queue.insert(v);
+        }
+
+        void del_var_eh(bool_var v) {
+            if (m_queue.contains(v))
+                m_queue.erase(v);
+        }
+
+        void unassign_var_eh(bool_var v) {
+            if (!m_queue.contains(v))
+                m_queue.insert(v);
+        }
+
+        void reset() {
+            m_queue.reset();
+        }
+
+        bool empty() const { return m_queue.empty(); }
+
+        bool_var next_var() { SASSERT(!empty()); return m_queue.erase_min(); }
+    };
+};
+
+#endif