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/******************************************************************************
* Top contributors (to current version):
* Andrew Reynolds, Tianyi Liang, Mathias Preiner
*
* This file is part of the cvc5 project.
*
* Copyright (c) 2009-2021 by the authors listed in the file AUTHORS
* in the top-level source directory and their institutional affiliations.
* All rights reserved. See the file COPYING in the top-level source
* directory for licensing information.
* ****************************************************************************
*
* Implementation of the solver state of the theory of strings.
*/
#include "theory/strings/solver_state.h"
#include "theory/rewriter.h"
#include "theory/strings/theory_strings_utils.h"
#include "theory/strings/word.h"
#include "util/rational.h"
using namespace std;
using namespace cvc5::context;
using namespace cvc5::kind;
namespace cvc5 {
namespace theory {
namespace strings {
SolverState::SolverState(context::Context* c,
context::UserContext* u,
Valuation& v)
: TheoryState(c, u, v), d_eeDisequalities(c), d_pendingConflictSet(c, false), d_pendingConflict(InferenceId::UNKNOWN)
{
d_zero = NodeManager::currentNM()->mkConst(Rational(0));
d_false = NodeManager::currentNM()->mkConst(false);
}
SolverState::~SolverState()
{
for (std::pair<const Node, EqcInfo*>& it : d_eqcInfo)
{
delete it.second;
}
}
const context::CDList<Node>& SolverState::getDisequalityList() const
{
return d_eeDisequalities;
}
void SolverState::addDisequality(TNode t1, TNode t2)
{
d_eeDisequalities.push_back(t1.eqNode(t2));
}
EqcInfo* SolverState::getOrMakeEqcInfo(Node eqc, bool doMake)
{
std::map<Node, EqcInfo*>::iterator eqc_i = d_eqcInfo.find(eqc);
if (eqc_i != d_eqcInfo.end())
{
return eqc_i->second;
}
if (doMake)
{
EqcInfo* ei = new EqcInfo(d_context);
d_eqcInfo[eqc] = ei;
return ei;
}
return nullptr;
}
TheoryModel* SolverState::getModel() { return d_valuation.getModel(); }
Node SolverState::getLengthExp(Node t, std::vector<Node>& exp, Node te)
{
Assert(areEqual(t, te));
Node lt = utils::mkNLength(te);
if (hasTerm(lt))
{
// use own length if it exists, leads to shorter explanation
return lt;
}
EqcInfo* ei = getOrMakeEqcInfo(t, false);
Node lengthTerm = ei ? ei->d_lengthTerm : Node::null();
if (lengthTerm.isNull())
{
// typically shouldnt be necessary
lengthTerm = t;
}
Debug("strings") << "SolverState::getLengthTerm " << t << " is " << lengthTerm
<< std::endl;
if (te != lengthTerm)
{
exp.push_back(te.eqNode(lengthTerm));
}
return Rewriter::rewrite(
NodeManager::currentNM()->mkNode(STRING_LENGTH, lengthTerm));
}
Node SolverState::getLength(Node t, std::vector<Node>& exp)
{
return getLengthExp(t, exp, t);
}
Node SolverState::explainNonEmpty(Node s)
{
Assert(s.getType().isStringLike());
Node emp = Word::mkEmptyWord(s.getType());
if (areDisequal(s, emp))
{
return s.eqNode(emp).negate();
}
Node sLen = utils::mkNLength(s);
if (areDisequal(sLen, d_zero))
{
return sLen.eqNode(d_zero).negate();
}
return Node::null();
}
bool SolverState::isEqualEmptyWord(Node s, Node& emps)
{
Node sr = getRepresentative(s);
if (sr.isConst())
{
if (Word::getLength(sr) == 0)
{
emps = sr;
return true;
}
}
return false;
}
void SolverState::setPendingPrefixConflictWhen(Node conf)
{
if (conf.isNull() || d_pendingConflictSet.get())
{
return;
}
InferInfo iiPrefixConf(InferenceId::STRINGS_PREFIX_CONFLICT);
iiPrefixConf.d_conc = d_false;
utils::flattenOp(AND, conf, iiPrefixConf.d_premises);
setPendingConflict(iiPrefixConf);
}
void SolverState::setPendingConflict(InferInfo& ii)
{
if (!d_pendingConflictSet.get())
{
d_pendingConflict = ii;
d_pendingConflictSet.set(true);
}
}
bool SolverState::hasPendingConflict() const { return d_pendingConflictSet; }
bool SolverState::getPendingConflict(InferInfo& ii) const
{
if (d_pendingConflictSet)
{
ii = d_pendingConflict;
return true;
}
return false;
}
std::pair<bool, Node> SolverState::entailmentCheck(options::TheoryOfMode mode,
TNode lit)
{
return d_valuation.entailmentCheck(mode, lit);
}
void SolverState::separateByLength(
const std::vector<Node>& n,
std::map<TypeNode, std::vector<std::vector<Node>>>& cols,
std::map<TypeNode, std::vector<Node>>& lts)
{
unsigned leqc_counter = 0;
// map (length, type) to an equivalence class identifier
std::map<std::pair<Node, TypeNode>, unsigned> eqc_to_leqc;
// backwards map
std::map<unsigned, std::pair<Node, TypeNode>> leqc_to_eqc;
// Collection of eqc for each identifier. Notice that some identifiers may
// not have an associated length in the mappings above, if the length of
// an equivalence class is unknown.
std::map<unsigned, std::vector<Node> > eqc_to_strings;
NodeManager* nm = NodeManager::currentNM();
for (const Node& eqc : n)
{
Assert(d_ee->getRepresentative(eqc) == eqc);
TypeNode tnEqc = eqc.getType();
EqcInfo* ei = getOrMakeEqcInfo(eqc, false);
Node lt = ei ? ei->d_lengthTerm : Node::null();
if (!lt.isNull())
{
lt = nm->mkNode(STRING_LENGTH, lt);
Node r = d_ee->getRepresentative(lt);
std::pair<Node, TypeNode> lkey(r, tnEqc);
if (eqc_to_leqc.find(lkey) == eqc_to_leqc.end())
{
eqc_to_leqc[lkey] = leqc_counter;
leqc_to_eqc[leqc_counter] = lkey;
leqc_counter++;
}
eqc_to_strings[eqc_to_leqc[lkey]].push_back(eqc);
}
else
{
eqc_to_strings[leqc_counter].push_back(eqc);
leqc_counter++;
}
}
for (const std::pair<const unsigned, std::vector<Node> >& p : eqc_to_strings)
{
Assert(!p.second.empty());
// get the type of the collection
TypeNode stn = p.second[0].getType();
cols[stn].emplace_back(p.second.begin(), p.second.end());
lts[stn].push_back(leqc_to_eqc[p.first].first);
}
}
} // namespace strings
} // namespace theory
} // namespace cvc5
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