Z3 sources

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

lib/smt_eq_justification.h

@@ -0,0 +1,85 @@
+/*++
+Copyright (c) 2006 Microsoft Corporation
+
+Module Name:
+
+    smt_eq_justification.h
+
+Abstract:
+
+    <abstract>
+
+Author:
+
+    Leonardo de Moura (leonardo) 2008-02-19.
+
+Revision History:
+
+--*/
+#ifndef _SMT_EQ_JUSTIFICATION_H_
+#define _SMT_EQ_JUSTIFICATION_H_
+
+#include"smt_literal.h"
+#include"tptr.h"
+
+namespace smt {
+
+    /**
+       \brief Proof like object used to track dependencies of equality propagation. 
+       The idea is to reduce the cost of dependency tracking for the most common
+       justifications used during equality propagation: (asserted equality & congruence).
+    */
+    class eq_justification { 
+        void * m_data;
+    public:
+        enum kind {
+            AXIOM,           //!< no justification, it is only used when proof generation is disabled
+            CONGRUENCE,
+            EQUATION,        //!< asserted equation
+            JUSTIFICATION    //!< fallback 
+        };
+
+        explicit eq_justification():
+            m_data(reinterpret_cast<void*>(static_cast<size_t>(AXIOM))) {
+        }
+
+        /**
+           \brief Create a justification for the congruence rule.
+           If commutativity == true, then it means it is a combined justification: commutativity + congruence.
+        */
+        explicit eq_justification(bool commutativity):
+            m_data(BOXTAGINT(void*, static_cast<unsigned>(commutativity), CONGRUENCE)) {
+        }
+        
+        explicit eq_justification(literal l):
+            m_data(BOXTAGINT(void*, l.index(), EQUATION)) {
+        }
+        
+        explicit eq_justification(justification * js):
+            m_data(TAG(void*, js, JUSTIFICATION)) {
+        }
+        
+        kind get_kind() const {
+            return static_cast<kind>(GET_TAG(m_data));
+        }
+
+        literal get_literal() const { SASSERT(get_kind() == EQUATION); return to_literal(UNBOXINT(m_data)); }
+        
+        justification * get_justification() const { SASSERT(get_kind() == JUSTIFICATION); return UNTAG(justification*, m_data); }
+
+        bool used_commutativity() const { SASSERT(get_kind() == CONGRUENCE); return UNBOXINT(m_data) != 0; }
+    
+        static eq_justification mk_axiom() {
+            return eq_justification();
+        }
+
+        static eq_justification mk_cg(bool comm = false) {
+            return eq_justification(comm);
+        }
+    };
+
+    const eq_justification null_eq_justification(static_cast<justification*>(0));
+};
+
+#endif /* _SMT_EQ_JUSTIFICATION_H_ */
+