Further refactoring ackermannization.

src/ackermannization/ackr_helper.h

@@ -0,0 +1,69 @@
+ /*++
+ Copyright (c) 2016 Microsoft Corporation
+
+ Module Name:
+
+  ackr_helper.h
+
+ Abstract:
+
+
+ Author:
+
+ Mikolas Janota
+
+ Revision History:
+ --*/
+#ifndef ACKR_HELPER_H_
+#define ACKR_HELPER_H_
+
+#include"bv_decl_plugin.h"
+
+class ackr_helper {
+    public:
+        typedef obj_hashtable<app>           app_set;
+        typedef obj_map<func_decl, app_set*> fun2terms_map;
+
+        ackr_helper(ast_manager& m) : m_bvutil(m) {}
+
+        /**
+        \brief  Determines if a given function should be Ackermannized.
+
+         This includes all uninterpreted functions but also "special" functions, e.g. OP_BSMOD0,
+         which are not marked as uninterpreted but effectively are.
+        */
+        inline bool should_ackermannize(app const * a) const {
+            if (a->get_family_id() == m_bvutil.get_family_id()) {
+                switch (a->get_decl_kind()) {
+                    case OP_BSDIV0:
+                    case OP_BUDIV0:
+                    case OP_BSREM0:
+                    case OP_BUREM0:
+                    case OP_BSMOD0:
+                        return true;
+                    default:
+                        return is_uninterp(a);
+                }
+            }
+            return (is_uninterp(a));
+        }
+
+        inline bv_util& bvutil() { return m_bvutil; }
+
+        /**
+        \brief Calculates an upper bound for congruence lemmas given a map of function of occurrences.
+        */
+        static double calculate_lemma_bound(fun2terms_map& occurrences);
+
+        /** \brief Calculate n choose 2. **/
+        inline static unsigned n_choose_2(unsigned n) { return n & 1 ? (n * (n >> 1)) : (n >> 1) * (n - 1); }
+
+        /** \brief Calculate n choose 2 guarded for overflow. Returns infinity if unsafe. **/
+        inline static double n_choose_2_chk(unsigned n) {
+            SASSERT(std::numeric_limits<unsigned>().max() & 32);
+            return n & (1 << 16) ? std::numeric_limits<double>().infinity() : n_choose_2(n);
+        }
+    private:
+        bv_util                              m_bvutil;
+};
+#endif /* ACKR_HELPER_H_6475 */