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       1                 :            : /******************************************************************************
       2                 :            :  * Top contributors (to current version):
       3                 :            :  *   Andrew Reynolds, Aina Niemetz
       4                 :            :  *
       5                 :            :  * This file is part of the cvc5 project.
       6                 :            :  *
       7                 :            :  * Copyright (c) 2009-2024 by the authors listed in the file AUTHORS
       8                 :            :  * in the top-level source directory and their institutional affiliations.
       9                 :            :  * All rights reserved.  See the file COPYING in the top-level source
      10                 :            :  * directory for licensing information.
      11                 :            :  * ****************************************************************************
      12                 :            :  *
      13                 :            :  * Equivalence class info for the theory of strings.
      14                 :            :  */
      15                 :            : 
      16                 :            : #include "cvc5_private.h"
      17                 :            : 
      18                 :            : #ifndef CVC5__THEORY__STRINGS__EQC_INFO_H
      19                 :            : #define CVC5__THEORY__STRINGS__EQC_INFO_H
      20                 :            : 
      21                 :            : #include <map>
      22                 :            : 
      23                 :            : #include "context/cdo.h"
      24                 :            : #include "context/context.h"
      25                 :            : #include "expr/node.h"
      26                 :            : 
      27                 :            : namespace cvc5::internal {
      28                 :            : namespace theory {
      29                 :            : namespace strings {
      30                 :            : 
      31                 :            : /**
      32                 :            :  * SAT-context-dependent information about an equivalence class. This
      33                 :            :  * information is updated eagerly as assertions are processed by the theory of
      34                 :            :  * strings at standard effort.
      35                 :            :  */
      36                 :            : class EqcInfo
      37                 :            : {
      38                 :            :  public:
      39                 :            :   EqcInfo(context::Context* c);
      40                 :     109215 :   ~EqcInfo() {}
      41                 :            :   /** add prefix constant
      42                 :            :    *
      43                 :            :    * This informs this equivalence class info that a term t in its
      44                 :            :    * equivalence class has a constant prefix (if isSuf=true) or suffix
      45                 :            :    * (if isSuf=false). The constant c (if non-null) is the value of that
      46                 :            :    * constant, if it has been computed already.
      47                 :            :    *
      48                 :            :    * If this method returns a non-null node ret, then ret is a conjunction
      49                 :            :    * corresponding to a conflict that holds in the current context.
      50                 :            :    */
      51                 :            :   Node addEndpointConst(Node t, Node c, bool isSuf);
      52                 :            :   /**
      53                 :            :    * If non-null, this is a term x from this eq class such that str.len( x )
      54                 :            :    * occurs as a term in this SAT context.
      55                 :            :    */
      56                 :            :   context::CDO<Node> d_lengthTerm;
      57                 :            :   /**
      58                 :            :    * If non-null, this is a term x from this eq class such that str.code( x )
      59                 :            :    * occurs as a term in this SAT context.
      60                 :            :    */
      61                 :            :   context::CDO<Node> d_codeTerm;
      62                 :            :   context::CDO<unsigned> d_cardinalityLemK;
      63                 :            :   context::CDO<Node> d_normalizedLength;
      64                 :            :   /**
      65                 :            :    * If this is a string equivalence class, this is
      66                 :            :    * a node that explains the longest constant prefix known of this
      67                 :            :    * equivalence class. This can either be:
      68                 :            :    * (1) A term from this equivalence class, including a constant "ABC" or
      69                 :            :    * concatenation term (str.++ "ABC" ...), or
      70                 :            :    * (2) A membership of the form (str.in.re x R) where x is in this
      71                 :            :    * equivalence class and R is a regular expression of the form
      72                 :            :    * (str.to.re "ABC") or (re.++ (str.to.re "ABC") ...).
      73                 :            :    *
      74                 :            :    * If this is an integer equivalence class, this is the lower bound
      75                 :            :    * of the value of this equivalence class.
      76                 :            :    */
      77                 :            :   context::CDO<Node> d_firstBound;
      78                 :            :   /** same as above, for suffix and integer upper bounds. */
      79                 :            :   context::CDO<Node> d_secondBound;
      80                 :            :   /**
      81                 :            :    * Make merge conflict. Let "bound term" refer to a term that is set
      82                 :            :    * as the data member of this class for d_firstBound or d_secondBound.
      83                 :            :    * This method is called when this implies that two terms occur in an
      84                 :            :    * equivalence class that have conflicting properties. For example,
      85                 :            :    * t may be (str.in_re x (re.++ (str.to_re "A") R2)) and prev may be
      86                 :            :    * (str.++ "B" y), where the equivalence class of x has merged into
      87                 :            :    * the equivalence class of (str.++ "B" y). This method would return
      88                 :            :    * the conflict:
      89                 :            :    *   (and (= x (str.++ "B" y)) (str.in_re x (re.++ (str.to_re "A") R2)))
      90                 :            :    * for this input.
      91                 :            :    *
      92                 :            :    * @param t The first bound term
      93                 :            :    * @param prev The second bound term
      94                 :            :    * @param isArith Whether this is an arithmetic conflict. This impacts
      95                 :            :    * whether (str.in_re x R) is processed as x or (str.len x).
      96                 :            :    * @return The node corresponding to the conflict.
      97                 :            :    */
      98                 :            :   static Node mkMergeConflict(Node t, Node prev, bool isArith);
      99                 :            : };
     100                 :            : 
     101                 :            : }  // namespace strings
     102                 :            : }  // namespace theory
     103                 :            : }  // namespace cvc5::internal
     104                 :            : 
     105                 :            : #endif /* CVC5__THEORY__STRINGS__EQC_INFO_H */