prepare char utilities as a stand-alone theory

src/smt/theory_char.h

@@ -0,0 +1,96 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    seq_char.h
+
+Abstract:
+
+    Solver for characters
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2020-5-16
+
+--*/
+#pragma once
+
+#include "ast/seq_decl_plugin.h"
+#include "ast/bv_decl_plugin.h"
+#include "ast/rewriter/bit_blaster/bit_blaster.h"
+#include "model/seq_factory.h"
+#include "smt/smt_theory.h"
+
+namespace smt {
+
+    class theory_char : public theory {
+
+        struct stats {
+            unsigned m_num_ackerman;
+            unsigned m_num_bounds;
+            unsigned m_num_blast;
+            stats() { reset(); }
+            void reset() { memset(this, 0, sizeof(*this)); }
+        };
+
+        seq_util         seq;
+        vector<literal_vector>  m_bits;
+        vector<expr_ref_vector> m_ebits;
+        unsigned_vector  m_var2value;
+        svector<theory_var> m_value2var;
+        bool             m_enabled { false };
+        bit_blaster      m_bb;
+        stats            m_stats;
+        symbol           m_bits2char;
+        seq_factory*     m_factory { nullptr };
+
+        struct reset_bits;
+
+
+        literal_vector const& get_bits(theory_var v);
+
+        expr_ref_vector const& get_ebits(theory_var v);
+
+        bool has_bits(theory_var v) const;
+
+        void init_bits(theory_var v);
+
+        bool get_value(theory_var v, unsigned& c);
+        
+        void enforce_ackerman(theory_var v, theory_var w);
+
+        void enforce_value_bound(theory_var v);
+
+        void enforce_bits();
+
+    public:
+
+        theory_char(context& ctx, family_id fid);
+        
+        void new_eq_eh(theory_var v1, theory_var v2) override;
+        void new_diseq_eh(theory_var v1, theory_var v2) override;
+        theory * mk_fresh(context * new_ctx) override { return alloc(theory_char, *new_ctx, get_family_id()); }
+        bool internalize_atom(app * atom, bool gate_ctx) override;
+        bool internalize_term(app * term) override;
+        void display(std::ostream& out) const override {}
+        final_check_status final_check_eh() override { return final_check() ? FC_DONE : FC_CONTINUE; }
+        void init_model(model_generator & mg) override;
+        model_value_proc * mk_value(enode * n, model_generator & mg) override;
+        void collect_statistics(::statistics& st) const override;
+
+        // Methods exposed when theory_char is a sub-theory of seq and not a stand-alone theory
+        // ensure coherence for character codes and equalities of shared symbols.
+        bool enabled() const { return m_enabled; }
+        bool final_check();
+        // <= atomic constraints on characters
+        void assign_le(theory_var v1, theory_var v2, literal lit);
+        void assign_lt(theory_var v1, theory_var v2, literal lit);
+        void new_const_char(theory_var v, unsigned c);
+        unsigned get_value(theory_var v);
+
+        void internalize_le(literal lit, app* term);        
+    };
+
+}
+