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z3/src/ast/rewriter/seq_rewriter.h
Nikolaj Bjorner 150c5c283d update re simplification
Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
2016-01-15 10:11:39 +05:30

140 lines
4.9 KiB
C++

/*++
Copyright (c) 2015 Microsoft Corporation
Module Name:
seq_rewriter.h
Abstract:
Basic rewriting rules for sequences constraints.
Author:
Nikolaj Bjorner (nbjorner) 2015-12-5
Notes:
--*/
#ifndef SEQ_REWRITER_H_
#define SEQ_REWRITER_H_
#include"seq_decl_plugin.h"
#include"arith_decl_plugin.h"
#include"rewriter_types.h"
#include"params.h"
#include"lbool.h"
#include"automaton.h"
class sym_expr {
enum ty {
t_char,
t_pred,
t_range
};
ty m_ty;
expr_ref m_t;
expr_ref m_s;
unsigned m_ref;
sym_expr(ty ty, expr_ref& t, expr_ref& s) : m_ty(ty), m_t(t), m_s(s), m_ref(0) {}
public:
expr_ref accept(expr* e);
static sym_expr* mk_char(expr_ref& t) { return alloc(sym_expr, t_char, t, t); }
static sym_expr* mk_char(ast_manager& m, expr* t) { expr_ref tr(t, m); return mk_char(tr); }
static sym_expr* mk_pred(expr_ref& t) { return alloc(sym_expr, t_pred, t, t); }
static sym_expr* mk_range(expr_ref& lo, expr_ref& hi) { return alloc(sym_expr, t_range, lo, hi); }
void inc_ref() { ++m_ref; }
void dec_ref() { --m_ref; if (m_ref == 0) dealloc(this); }
std::ostream& display(std::ostream& out) const;
bool is_char() const { return m_ty == t_char; }
bool is_pred() const { return !is_char(); }
expr* get_char() const { SASSERT(is_char()); return m_t; }
};
class sym_expr_manager {
public:
void inc_ref(sym_expr* s) { if (s) s->inc_ref(); }
void dec_ref(sym_expr* s) { if (s) s->dec_ref(); }
};
typedef automaton<sym_expr, sym_expr_manager> eautomaton;
class re2automaton {
ast_manager& m;
sym_expr_manager sm;
seq_util u;
bv_util bv;
eautomaton* re2aut(expr* e);
eautomaton* seq2aut(expr* e);
public:
re2automaton(ast_manager& m);
eautomaton* operator()(expr* e);
};
/**
\brief Cheap rewrite rules for seq constraints
*/
class seq_rewriter {
seq_util m_util;
arith_util m_autil;
re2automaton m_re2aut;
expr_ref_vector m_es, m_lhs, m_rhs;
br_status mk_seq_concat(expr* a, expr* b, expr_ref& result);
br_status mk_seq_length(expr* a, expr_ref& result);
br_status mk_seq_extract(expr* a, expr* b, expr* c, expr_ref& result);
br_status mk_seq_contains(expr* a, expr* b, expr_ref& result);
br_status mk_seq_at(expr* a, expr* b, expr_ref& result);
br_status mk_seq_index(expr* a, expr* b, expr* c, expr_ref& result);
br_status mk_seq_replace(expr* a, expr* b, expr* c, expr_ref& result);
br_status mk_seq_prefix(expr* a, expr* b, expr_ref& result);
br_status mk_seq_suffix(expr* a, expr* b, expr_ref& result);
br_status mk_str_itos(expr* a, expr_ref& result);
br_status mk_str_stoi(expr* a, expr_ref& result);
br_status mk_str_in_regexp(expr* a, expr* b, expr_ref& result);
br_status mk_str_to_regexp(expr* a, expr_ref& result);
br_status mk_re_concat(expr* a, expr* b, expr_ref& result);
br_status mk_re_union(expr* a, expr* b, expr_ref& result);
br_status mk_re_inter(expr* a, expr* b, expr_ref& result);
br_status mk_re_star(expr* a, expr_ref& result);
br_status mk_re_plus(expr* a, expr_ref& result);
br_status mk_re_opt(expr* a, expr_ref& result);
br_status mk_re_loop(unsigned num_args, expr* const* args, expr_ref& result);
bool set_empty(unsigned sz, expr* const* es, bool all, expr_ref_vector& lhs, expr_ref_vector& rhs);
bool is_subsequence(unsigned n, expr* const* l, unsigned m, expr* const* r,
expr_ref_vector& lhs, expr_ref_vector& rhs, bool& is_sat);
bool length_constrained(unsigned n, expr* const* l, unsigned m, expr* const* r,
expr_ref_vector& lhs, expr_ref_vector& rhs, bool& is_sat);
bool min_length(unsigned n, expr* const* es, unsigned& len);
expr* concat_non_empty(unsigned n, expr* const* es);
void add_next(u_map<expr*>& next, expr_ref_vector& trail, unsigned idx, expr* cond);
bool is_sequence(expr* e, expr_ref_vector& seq);
bool is_sequence(eautomaton& aut, expr_ref_vector& seq);
bool is_epsilon(expr* e) const;
public:
seq_rewriter(ast_manager & m, params_ref const & p = params_ref()):
m_util(m), m_autil(m), m_re2aut(m), m_es(m), m_lhs(m), m_rhs(m) {
}
ast_manager & m() const { return m_util.get_manager(); }
family_id get_fid() const { return m_util.get_family_id(); }
void updt_params(params_ref const & p) {}
static void get_param_descrs(param_descrs & r) {}
br_status mk_app_core(func_decl * f, unsigned num_args, expr * const * args, expr_ref & result);
br_status mk_eq_core(expr * lhs, expr * rhs, expr_ref & result);
bool reduce_eq(expr* l, expr* r, expr_ref_vector& lhs, expr_ref_vector& rhs, bool& change);
bool reduce_eq(expr_ref_vector& ls, expr_ref_vector& rs, expr_ref_vector& lhs, expr_ref_vector& rhs, bool& change);
void add_seqs(expr_ref_vector const& ls, expr_ref_vector const& rs, expr_ref_vector& lhs, expr_ref_vector& rhs);
};
#endif