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| 1 | +/*******************************************************************\ |
| 2 | +
|
| 3 | +Module: Guard Data Structure |
| 4 | +
|
| 5 | +Author: Romain Brenguier, [email protected] |
| 6 | +
|
| 7 | +\*******************************************************************/ |
| 8 | + |
| 9 | +/// \file |
| 10 | +/// Implementation of guards using BDDs |
| 11 | + |
| 12 | +#include "guard_bdd.h" |
| 13 | + |
| 14 | +#include <algorithm> |
| 15 | +#include <ostream> |
| 16 | +#include <set> |
| 17 | + |
| 18 | +#include <solvers/bdd/bdd.h> |
| 19 | +#include <solvers/prop/bdd_expr.h> |
| 20 | +#include <util/expr_util.h> |
| 21 | +#include <util/invariant.h> |
| 22 | +#include <util/make_unique.h> |
| 23 | +#include <util/namespace.h> |
| 24 | +#include <util/simplify_utils.h> |
| 25 | +#include <util/std_expr.h> |
| 26 | +#include <util/symbol_table.h> |
| 27 | + |
| 28 | +guard_bddt::guard_bddt(const exprt &e, bdd_exprt &manager) |
| 29 | + : manager(manager), bdd(manager.from_expr(e)) |
| 30 | +{ |
| 31 | +} |
| 32 | + |
| 33 | +guard_bddt &guard_bddt::operator=(const guard_bddt &other) |
| 34 | +{ |
| 35 | + PRECONDITION(&manager == &other.manager); |
| 36 | + bdd = other.bdd; |
| 37 | + return *this; |
| 38 | +} |
| 39 | + |
| 40 | +guard_bddt &guard_bddt::operator=(guard_bddt &&other) |
| 41 | +{ |
| 42 | + PRECONDITION(&manager == &other.manager); |
| 43 | + std::swap(bdd, other.bdd); |
| 44 | + return *this; |
| 45 | +} |
| 46 | + |
| 47 | +exprt guard_bddt::guard_expr(exprt expr) const |
| 48 | +{ |
| 49 | + if(is_true()) |
| 50 | + { |
| 51 | + // do nothing |
| 52 | + return expr; |
| 53 | + } |
| 54 | + else |
| 55 | + { |
| 56 | + if(expr.is_false()) |
| 57 | + { |
| 58 | + return boolean_negate(as_expr()); |
| 59 | + } |
| 60 | + else |
| 61 | + { |
| 62 | + return implies_exprt{as_expr(), expr}; |
| 63 | + } |
| 64 | + } |
| 65 | +} |
| 66 | + |
| 67 | +guard_bddt &guard_bddt::append(const guard_bddt &guard) |
| 68 | +{ |
| 69 | + bdd = bdd.bdd_and(guard.bdd); |
| 70 | + return *this; |
| 71 | +} |
| 72 | + |
| 73 | +guard_bddt &guard_bddt::add(const exprt &expr) |
| 74 | +{ |
| 75 | + bdd = bdd.bdd_and(manager.from_expr(expr)); |
| 76 | + return *this; |
| 77 | +} |
| 78 | + |
| 79 | +guard_bddt &operator-=(guard_bddt &g1, const guard_bddt &g2) |
| 80 | +{ |
| 81 | + g1.bdd = g1.bdd.constrain(g2.bdd.bdd_or(g1.bdd)); |
| 82 | + return g1; |
| 83 | +} |
| 84 | + |
| 85 | +guard_bddt &operator|=(guard_bddt &g1, const guard_bddt &g2) |
| 86 | +{ |
| 87 | + g1.bdd = g1.bdd.bdd_or(g2.bdd); |
| 88 | + return g1; |
| 89 | +} |
| 90 | + |
| 91 | +exprt guard_bddt::as_expr() const |
| 92 | +{ |
| 93 | + return manager.as_expr(bdd); |
| 94 | +} |
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