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/******************************************************************************
* Top contributors (to current version):
* Andrew Reynolds
*
* 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.
* ****************************************************************************
*
* Equivalence class info for the theory of strings.
*/
#include "cvc5_private.h"
#ifndef CVC5__THEORY__STRINGS__EQC_INFO_H
#define CVC5__THEORY__STRINGS__EQC_INFO_H
#include <map>
#include "context/cdo.h"
#include "context/context.h"
#include "expr/node.h"
namespace cvc5 {
namespace theory {
namespace strings {
/**
* SAT-context-dependent information about an equivalence class. This
* information is updated eagerly as assertions are processed by the theory of
* strings at standard effort.
*/
class EqcInfo
{
public:
EqcInfo(context::Context* c);
~EqcInfo() {}
/** add prefix constant
*
* This informs this equivalence class info that a term t in its
* equivalence class has a constant prefix (if isSuf=true) or suffix
* (if isSuf=false). The constant c (if non-null) is the value of that
* constant, if it has been computed already.
*
* If this method returns a non-null node ret, then ret is a conjunction
* corresponding to a conflict that holds in the current context.
*/
Node addEndpointConst(Node t, Node c, bool isSuf);
/**
* If non-null, this is a term x from this eq class such that str.len( x )
* occurs as a term in this SAT context.
*/
context::CDO<Node> d_lengthTerm;
/**
* If non-null, this is a term x from this eq class such that str.code( x )
* occurs as a term in this SAT context.
*/
context::CDO<Node> d_codeTerm;
context::CDO<unsigned> d_cardinalityLemK;
context::CDO<Node> d_normalizedLength;
/**
* If this is a string equivalence class, this is
* a node that explains the longest constant prefix known of this
* equivalence class. This can either be:
* (1) A term from this equivalence class, including a constant "ABC" or
* concatenation term (str.++ "ABC" ...), or
* (2) A membership of the form (str.in.re x R) where x is in this
* equivalence class and R is a regular expression of the form
* (str.to.re "ABC") or (re.++ (str.to.re "ABC") ...).
*
* If this is an integer equivalence class, this is the lower bound
* of the value of this equivalence class.
*/
context::CDO<Node> d_firstBound;
/** same as above, for suffix and integer upper bounds. */
context::CDO<Node> d_secondBound;
/**
* Make merge conflict. Let "bound term" refer to a term that is set
* as the data member of this class for d_firstBound or d_secondBound.
* This method is called when this implies that two terms occur in an
* equivalence class that have conflicting properties. For example,
* t may be (str.in_re x (re.++ (str.to_re "A") R2)) and prev may be
* (str.++ "B" y), where the equivalence class of x has merged into
* the equivalence class of (str.++ "B" y). This method would return
* the conflict:
* (and (= x (str.++ "B" y)) (str.in_re x (re.++ (str.to_re "A") R2)))
* for this input.
*/
static Node mkMergeConflict(Node t, Node prev);
};
} // namespace strings
} // namespace theory
} // namespace cvc5
#endif /* CVC5__THEORY__STRINGS__EQC_INFO_H */
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