SQLite

int sqlite3Fts5IterNextFrom(Fts5IndexIter*, i64 iMatch);

/*
** Close an iterator opened by sqlite3Fts5IndexQuery().
*/
void sqlite3Fts5IterClose(Fts5IndexIter*);

/*
** Close the reader blob handle, if it is open.
*/
void sqlite3Fts5IndexCloseReader(Fts5Index*);

/*
** This interface is used by the fts5vocab module.
*/
const char *sqlite3Fts5IterTerm(Fts5IndexIter*, int*);
int sqlite3Fts5IterNextScan(Fts5IndexIter*);

  fts5GetVarint32(&pLeaf->p[pLeaf->szLeaf], ret);
  return ret;
}

/*
** Close the read-only blob handle, if it is open.
*/
void sqlite3Fts5IndexCloseReader(Fts5Index *p){
  if( p->pReader ){
    sqlite3_blob *pReader = p->pReader;
    p->pReader = 0;
    sqlite3_blob_close(pReader);
  }
}

      ** is required.  */
      sqlite3_blob *pBlob = p->pReader;
      p->pReader = 0;
      rc = sqlite3_blob_reopen(pBlob, iRowid);
      assert( p->pReader==0 );
      p->pReader = pBlob;
      if( rc!=SQLITE_OK ){
        sqlite3Fts5IndexCloseReader(p);
      }
      if( rc==SQLITE_ABORT ) rc = SQLITE_OK;
    }

    /* If the blob handle is not open at this point, open it and seek 
    ** to the requested entry.  */
    if( p->pReader==0 && rc==SQLITE_OK ){

/*
** Commit data to disk.
*/
int sqlite3Fts5IndexSync(Fts5Index *p){
  assert( p->rc==SQLITE_OK );
  fts5IndexFlush(p);
  sqlite3Fts5IndexCloseReader(p);
  return fts5IndexReturn(p);
}

/*
** Discard any data stored in the in-memory hash tables. Do not write it
** to the database. Additionally, assume that the contents of the %_data
** table may have changed on disk. So any in-memory caches of %_data 
** records must be invalidated.
*/
int sqlite3Fts5IndexRollback(Fts5Index *p){
  sqlite3Fts5IndexCloseReader(p);
  fts5IndexDiscardData(p);
  fts5StructureInvalidate(p);
  /* assert( p->rc==SQLITE_OK ); */
  return SQLITE_OK;
}

/*

        if( pSeg->pLeaf ) pRet->xSetOutputs(pRet, pSeg);
      }
    }

    if( p->rc ){
      sqlite3Fts5IterClose((Fts5IndexIter*)pRet);
      pRet = 0;
      sqlite3Fts5IndexCloseReader(p);
    }

    *ppIter = (Fts5IndexIter*)pRet;
    sqlite3Fts5BufferFree(&buf);
  }
  return fts5IndexReturn(p);
}

** Close an iterator opened by an earlier call to sqlite3Fts5IndexQuery().
*/
void sqlite3Fts5IterClose(Fts5IndexIter *pIndexIter){
  if( pIndexIter ){
    Fts5Iter *pIter = (Fts5Iter*)pIndexIter;
    Fts5Index *pIndex = pIter->pIndex;
    fts5MultiIterFree(pIter);
    sqlite3Fts5IndexCloseReader(pIndex);
  }
}

/*
** Read and decode the "averages" record from the database. 
**
** Parameter anSize must point to an array of size nCol, where nCol is

  sqlite3_free(pCsr->apRankArg);

  if( CsrFlagTest(pCsr, FTS5CSR_FREE_ZRANK) ){
    sqlite3_free(pCsr->zRank);
    sqlite3_free(pCsr->zRankArgs);
  }

  sqlite3Fts5IndexCloseReader(pTab->p.pIndex);
  memset(&pCsr->ePlan, 0, sizeof(Fts5Cursor) - ((u8*)&pCsr->ePlan - (u8*)pCsr));
}


/*
** Close the cursor.  For additional information see the documentation
** on the xClose method of the virtual table interface.

  CREATE VIRTUAL TABLE x1 USING fts5(z);
  INSERT INTO x1 VALUES('a b c a b c a b c');
} {}

do_catchsql_test 14.2 {
  SELECT matchinfo(x1, 'd') FROM x1('a b c');
} {1 {unrecognized matchinfo flag: d}}

#-------------------------------------------------------------------------
# Test using matchinfo() and similar on a non-full-text query
#
do_execsql_test 15.0 {
  CREATE VIRTUAL TABLE t1 USING fts5(x, y);
  INSERT INTO t1 VALUES('a', 'b');
  INSERT INTO t1 VALUES('c', 'd');
}

do_execsql_test 15.1 {
  SELECT quote(matchinfo(t1, 'n')) FROM t1 LIMIT 1;
} {X'02000000'}

do_execsql_test 15.2 {
  DELETE FROM t1_content WHERE rowid=1;
  SELECT quote(matchinfo(t1, 'n')) FROM t1 LIMIT 1;
} {X'02000000'}

fts5_aux_test_functions db
do_execsql_test 15.3 {
  SELECT fts5_test_all(t1) FROM t1 LIMIT 1;
} {
  {columnsize {0 0} columntext {c d} columntotalsize {2 2} poslist {} tokenize {c d} rowcount 2}
}

finish_test

#else
  /* Throw and error for the GENERATED ALWAYS AS clause if the
  ** SQLITE_OMIT_GENERATED_COLUMNS compile-time option is used. */
  sqlite3ErrorMsg(pParse, "GENERATED ALWAYS AS not supported");
  sqlite3ExprDelete(pParse->db, pExpr);
#endif
}




































/*
** Generate code that will increment the schema cookie.
**
** The schema cookie is used to determine when the schema for the
** database changes.  After each schema change, the cookie value
** changes.  When a process first reads the schema it records the

      pColl->xDel = 0;         /* Do not copy the destructor */
      return SQLITE_OK;
    }
  }
  return SQLITE_ERROR;
}














































/*
** This routine is called on a collation sequence before it is used to
** check that it is defined. An undefined collation sequence exists when
** a database is loaded that contains references to collation sequences
** that have not been defined by sqlite3_create_collation() etc.
**
** If required, this routine calls the 'collation needed' callback to

** this routine.  sqlite3LocateCollSeq() invokes the collation factory
** if necessary and generates an error message if the collating sequence
** cannot be found.
**
** See also: sqlite3LocateCollSeq(), sqlite3GetCollSeq()
*/
CollSeq *sqlite3FindCollSeq(
  sqlite3 *db,          /* Database connection to search */
  u8 enc,               /* Desired text encoding */
  const char *zName,    /* Name of the collating sequence.  Might be NULL */
  int create            /* True to create CollSeq if doesn't already exist */
){
  CollSeq *pColl;
  if( zName ){
    pColl = findCollSeqEntry(db, zName, create);
  }else{
    pColl = db->pDfltColl;
  }
  assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
  assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
  if( pColl ) pColl += enc-1;
  return pColl;
}

/*
** This function is responsible for invoking the collation factory callback
** or substituting a collation sequence of a different encoding when the
** requested collation sequence is not available in the desired encoding.
** 
** If it is not NULL, then pColl must point to the database native encoding 
** collation sequence with name zName, length nName.
**
** The return value is either the collation sequence to be used in database
** db for collation type name zName, length nName, or NULL, if no collation
** sequence can be found.  If no collation is found, leave an error message.
**
** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq()
*/
CollSeq *sqlite3GetCollSeq(
  Parse *pParse,        /* Parsing context */
  u8 enc,               /* The desired encoding for the collating sequence */
  CollSeq *pColl,       /* Collating sequence with native encoding, or NULL */
  const char *zName     /* Collating sequence name */
){
  CollSeq *p;
  sqlite3 *db = pParse->db;

  p = pColl;
  if( !p ){
    p = sqlite3FindCollSeq(db, enc, zName, 0);
  }
  if( !p || !p->xCmp ){
    /* No collation sequence of this type for this encoding is registered.
    ** Call the collation factory to see if it can supply us with one.
    */
    callCollNeeded(db, enc, zName);
    p = sqlite3FindCollSeq(db, enc, zName, 0);
  }
  if( p && !p->xCmp && synthCollSeq(db, p) ){
    p = 0;
  }
  assert( !p || p->xCmp );
  if( p==0 ){
    sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
    pParse->rc = SQLITE_ERROR_MISSING_COLLSEQ;
  }
  return p;
}

/*
** This function returns the collation sequence for database native text
** encoding identified by the string zName.
**
** If the requested collation sequence is not available, or not available
** in the database native encoding, the collation factory is invoked to
** request it. If the collation factory does not supply such a sequence,
** and the sequence is available in another text encoding, then that is
** returned instead.
**
** If no versions of the requested collations sequence are available, or
** another error occurs, NULL is returned and an error message written into
** pParse.
**
** This routine is a wrapper around sqlite3FindCollSeq().  This routine
** invokes the collation factory if the named collation cannot be found
** and generates an error message.
**
** See also: sqlite3FindCollSeq(), sqlite3GetCollSeq()
*/
CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName){
  sqlite3 *db = pParse->db;
  u8 enc = ENC(db);
  u8 initbusy = db->init.busy;
  CollSeq *pColl;

  pColl = sqlite3FindCollSeq(db, enc, zName, initbusy);
  if( !initbusy && (!pColl || !pColl->xCmp) ){
    pColl = sqlite3GetCollSeq(pParse, enc, pColl, zName);
  }

  return pColl;
}

/* During the search for the best function definition, this procedure
** is called to test how well the function passed as the first argument
** matches the request for a function with nArg arguments in a system
** that uses encoding enc. The value returned indicates how well the

    pColl = sqlite3ExprCollSeq(pParse, pLeft);
    if( !pColl ){
      pColl = sqlite3ExprCollSeq(pParse, pRight);
    }
  }
  return pColl;
}

/* Expresssion p is a comparison operator.  Return a collation sequence
** appropriate for the comparison operator.
**
** This is normally just a wrapper around sqlite3BinaryCompareCollSeq().
** However, if the OP_Commuted flag is set, then the order of the operands
** is reversed in the sqlite3BinaryCompareCollSeq() call so that the
** correct collating sequence is found.
*/
CollSeq *sqlite3ExprCompareCollSeq(Parse *pParse, Expr *p){
  if( ExprHasProperty(p, EP_Commuted) ){
    return sqlite3BinaryCompareCollSeq(pParse, p->pRight, p->pLeft);
  }else{
    return sqlite3BinaryCompareCollSeq(pParse, p->pLeft, p->pRight);
  }
}

/*
** Generate code for a comparison operator.
*/
static int codeCompare(
  Parse *pParse,    /* The parsing (and code generating) context */
  Expr *pLeft,      /* The left operand */
  Expr *pRight,     /* The right operand */
  int opcode,       /* The comparison opcode */
  int in1, int in2, /* Register holding operands */
  int dest,         /* Jump here if true.  */
  int jumpIfNull,   /* If true, jump if either operand is NULL */
  int isCommuted    /* The comparison has been commuted */
){
  int p5;
  int addr;
  CollSeq *p4;

  if( isCommuted ){
    p4 = sqlite3BinaryCompareCollSeq(pParse, pRight, pLeft);
  }else{
    p4 = sqlite3BinaryCompareCollSeq(pParse, pLeft, pRight);
  }
  p5 = binaryCompareP5(pLeft, pRight, jumpIfNull);
  addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
                           (void*)p4, P4_COLLSEQ);
  sqlite3VdbeChangeP5(pParse->pVdbe, (u8)p5);
  return addr;
}

  Expr *pRight = pExpr->pRight;
  int nLeft = sqlite3ExprVectorSize(pLeft);
  int i;
  int regLeft = 0;
  int regRight = 0;
  u8 opx = op;
  int addrDone = sqlite3VdbeMakeLabel(pParse);
  int isCommuted = ExprHasProperty(pExpr,EP_Commuted);

  if( nLeft!=sqlite3ExprVectorSize(pRight) ){
    sqlite3ErrorMsg(pParse, "row value misused");
    return;
  }
  assert( pExpr->op==TK_EQ || pExpr->op==TK_NE 
       || pExpr->op==TK_IS || pExpr->op==TK_ISNOT 

  for(i=0; 1 /*Loop exits by "break"*/; i++){
    int regFree1 = 0, regFree2 = 0;
    Expr *pL, *pR; 
    int r1, r2;
    assert( i>=0 && i<nLeft );
    r1 = exprVectorRegister(pParse, pLeft, i, regLeft, &pL, &regFree1);
    r2 = exprVectorRegister(pParse, pRight, i, regRight, &pR, &regFree2);
    codeCompare(pParse, pL, pR, opx, r1, r2, dest, p5, isCommuted);
    testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
    testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
    testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
    testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
    testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
    testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
    sqlite3ReleaseTempReg(pParse, regFree1);

      Expr *pLeft = pExpr->pLeft;
      if( sqlite3ExprIsVector(pLeft) ){
        codeVectorCompare(pParse, pExpr, target, op, p5);
      }else{
        r1 = sqlite3ExprCodeTemp(pParse, pLeft, &regFree1);
        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
        codeCompare(pParse, pLeft, pExpr->pRight, op,
            r1, r2, inReg, SQLITE_STOREP2 | p5,
            ExprHasProperty(pExpr,EP_Commuted));
        assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
        assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
        assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
        assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
        assert(TK_EQ==OP_Eq); testcase(op==OP_Eq); VdbeCoverageIf(v,op==OP_Eq);
        assert(TK_NE==OP_Ne); testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
        testcase( regFree1==0 );

    case TK_NE:
    case TK_EQ: {
      if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
      testcase( jumpIfNull==0 );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull, ExprHasProperty(pExpr,EP_Commuted));
      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
      assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
      assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq);
      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull==SQLITE_NULLEQ);
      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull!=SQLITE_NULLEQ);

    case TK_NE:
    case TK_EQ: {
      if( sqlite3ExprIsVector(pExpr->pLeft) ) goto default_expr;
      testcase( jumpIfNull==0 );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      r2 = sqlite3ExprCodeTemp(pParse, pExpr->pRight, &regFree2);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op,
                  r1, r2, dest, jumpIfNull,ExprHasProperty(pExpr,EP_Commuted));
      assert(TK_LT==OP_Lt); testcase(op==OP_Lt); VdbeCoverageIf(v,op==OP_Lt);
      assert(TK_LE==OP_Le); testcase(op==OP_Le); VdbeCoverageIf(v,op==OP_Le);
      assert(TK_GT==OP_Gt); testcase(op==OP_Gt); VdbeCoverageIf(v,op==OP_Gt);
      assert(TK_GE==OP_Ge); testcase(op==OP_Ge); VdbeCoverageIf(v,op==OP_Ge);
      assert(TK_EQ==OP_Eq); testcase(op==OP_Eq);
      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull!=SQLITE_NULLEQ);
      VdbeCoverageIf(v, op==OP_Eq && jumpIfNull==SQLITE_NULLEQ);

      return 0;
    }else if( pA->op==TK_COLLATE ){
      if( sqlite3_stricmp(pA->u.zToken,pB->u.zToken)!=0 ) return 2;
    }else if( ALWAYS(pB->u.zToken!=0) && strcmp(pA->u.zToken,pB->u.zToken)!=0 ){
      return 2;
    }
  }
  if( (pA->flags & (EP_Distinct|EP_Commuted))
     != (pB->flags & (EP_Distinct|EP_Commuted)) ) return 2;
  if( (combinedFlags & EP_TokenOnly)==0 ){
    if( combinedFlags & EP_xIsSelect ) return 2;
    if( (combinedFlags & EP_FixedCol)==0
     && sqlite3ExprCompare(pParse, pA->pLeft, pB->pLeft, iTab) ) return 2;
    if( sqlite3ExprCompare(pParse, pA->pRight, pB->pRight, iTab) ) return 2;
    if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList, iTab) ) return 2;
    if( pA->op!=TK_STRING

          pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
        }
        if( pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0) ){
          sqlite3MultiWrite(pParse);
          sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
                                   regNewData, 1, 0, OE_Replace, 1, -1);
          sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
          VdbeCoverage(v);
          sqlite3RowidConstraint(pParse, OE_Abort, pTab);
        }else{
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
          assert( HasRowid(pTab) );
          /* This OP_Delete opcode fires the pre-update-hook only. It does
          ** not modify the b-tree. It is more efficient to let the coming
          ** OP_Insert replace the existing entry than it is to delete the

  pRight = pExpr->pRight;
  pLeft = pExpr->pLeft;
  assert( pRight!=0 );
  assert( pLeft!=0 );
  if( pRight->op==TK_COLUMN
   && !ExprHasProperty(pRight, EP_FixedCol)
   && sqlite3ExprIsConstant(pLeft)
   && sqlite3IsBinary(sqlite3ExprCompareCollSeq(pConst->pParse,pExpr))
  ){
    constInsert(pConst, pRight, pLeft);
  }else
  if( pLeft->op==TK_COLUMN
   && !ExprHasProperty(pLeft, EP_FixedCol)
   && sqlite3ExprIsConstant(pRight)
   && sqlite3IsBinary(sqlite3ExprCompareCollSeq(pConst->pParse,pExpr))
  ){
    constInsert(pConst, pLeft, pRight);
  }
}

/*
** This is a Walker expression callback.  pExpr is a candidate expression

#define EP_HasFunc    0x000004 /* Contains one or more functions of any kind */
#define EP_FixedCol   0x000008 /* TK_Column with a known fixed value */
#define EP_Agg        0x000010 /* Contains one or more aggregate functions */
#define EP_VarSelect  0x000020 /* pSelect is correlated, not constant */
#define EP_DblQuoted  0x000040 /* token.z was originally in "..." */
#define EP_InfixFunc  0x000080 /* True for an infix function: LIKE, GLOB, etc */
#define EP_Collate    0x000100 /* Tree contains a TK_COLLATE operator */
#define EP_Commuted   0x000200 /* Comparison operator has been commuted */
#define EP_IntValue   0x000400 /* Integer value contained in u.iValue */
#define EP_xIsSelect  0x000800 /* x.pSelect is valid (otherwise x.pList is) */
#define EP_Skip       0x001000 /* Operator does not contribute to affinity */
#define EP_Reduced    0x002000 /* Expr struct EXPR_REDUCEDSIZE bytes only */
#define EP_TokenOnly  0x004000 /* Expr struct EXPR_TOKENONLYSIZE bytes only */
#define EP_Win        0x008000 /* Contains window functions */
#define EP_MemToken   0x010000 /* Need to sqlite3DbFree() Expr.zToken */

int sqlite3TransferBindings(sqlite3_stmt *, sqlite3_stmt *);
void sqlite3ParserReset(Parse*);
#ifdef SQLITE_ENABLE_NORMALIZE
char *sqlite3Normalize(Vdbe*, const char*);
#endif
int sqlite3Reprepare(Vdbe*);
void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
CollSeq *sqlite3ExprCompareCollSeq(Parse*,Expr*);
CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);
int sqlite3TempInMemory(const sqlite3*);
const char *sqlite3JournalModename(int);
#ifndef SQLITE_OMIT_WAL
  int sqlite3Checkpoint(sqlite3*, int, int, int*, int*);
  int sqlite3WalDefaultHook(void*,sqlite3*,const char*,int);
#endif

              CollSeq *pColl;
              Parse *pParse = pWC->pWInfo->pParse;
              pX = pTerm->pExpr;
              if( !sqlite3IndexAffinityOk(pX, pScan->idxaff) ){
                continue;
              }
              assert(pX->pLeft);
              pColl = sqlite3ExprCompareCollSeq(pParse, pX);

              if( pColl==0 ) pColl = pParse->db->pDfltColl;
              if( sqlite3StrICmp(pColl->zName, pScan->zCollName) ){
                continue;
              }
            }
            if( (pTerm->eOperator & (WO_EQ|WO_IS))!=0
             && (pX = pTerm->pExpr->pRight)->op==TK_COLUMN

      Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
      testcase( iCol==BMS-1 );
      testcase( iCol==BMS );
      if( (idxCols & cMask)==0 ){
        Expr *pX = pTerm->pExpr;
        idxCols |= cMask;
        pIdx->aiColumn[n] = pTerm->u.leftColumn;
        pColl = sqlite3ExprCompareCollSeq(pParse, pX);
        pIdx->azColl[n] = ALWAYS(pColl) ? pColl->zName : sqlite3StrBINARY;
        n++;
      }
    }
  }
  assert( (u32)n==pLoop->u.btree.nEq );

  /* Add additional columns needed to make the automatic index into

  while( pWhere->op==TK_AND ){
    if( !whereUsablePartialIndex(iTab,pWC,pWhere->pLeft) ) return 0;
    pWhere = pWhere->pRight;
  }
  if( pParse->db->flags & SQLITE_EnableQPSG ) pParse = 0;
  for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    Expr *pExpr;

    pExpr = pTerm->pExpr;
    if( (!ExprHasProperty(pExpr, EP_FromJoin) || pExpr->iRightJoinTable==iTab)
     && sqlite3ExprImpliesExpr(pParse, pExpr, pWhere, iTab) 
    ){
      return 1;
    }
  }

  HiddenIndexInfo *pHidden = (HiddenIndexInfo*)&pIdxInfo[1];
  const char *zRet = 0;
  if( iCons>=0 && iCons<pIdxInfo->nConstraint ){
    CollSeq *pC = 0;
    int iTerm = pIdxInfo->aConstraint[iCons].iTermOffset;
    Expr *pX = pHidden->pWC->a[iTerm].pExpr;
    if( pX->pLeft ){
      pC = sqlite3ExprCompareCollSeq(pHidden->pParse, pX);
    }
    zRet = (pC ? pC->zName : sqlite3StrBINARY);
  }
  return zRet;
}

/*

#  define TERM_VNULL    0x00   /* Disabled if not using stat4 */
#endif
#define TERM_LIKEOPT    0x100  /* Virtual terms from the LIKE optimization */
#define TERM_LIKECOND   0x200  /* Conditionally this LIKE operator term */
#define TERM_LIKE       0x400  /* The original LIKE operator */
#define TERM_IS         0x800  /* Term.pExpr is an IS operator */
#define TERM_VARSELECT  0x1000 /* Term.pExpr contains a correlated sub-query */


/*
** An instance of the WhereScan object is used as an iterator for locating
** terms in the WHERE clause that are useful to the query planner.
*/
struct WhereScan {
  WhereClause *pOrigWC;      /* Original, innermost WhereClause */

  assert( TK_GE==TK_EQ+4 );
  return op==TK_IN || (op>=TK_EQ && op<=TK_GE) || op==TK_ISNULL || op==TK_IS;
}

/*
** Commute a comparison operator.  Expressions of the form "X op Y"
** are converted into "Y op X".













*/
static u16 exprCommute(Parse *pParse, Expr *pExpr){

  if( pExpr->pLeft->op==TK_VECTOR







   || pExpr->pRight->op==TK_VECTOR

   || sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft, pExpr->pRight) !=



      sqlite3BinaryCompareCollSeq(pParse, pExpr->pRight, pExpr->pLeft)
  ){
    pExpr->flags ^= EP_Commuted;

  }
  SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
  if( pExpr->op>=TK_GT ){
    assert( TK_LT==TK_GT+2 );
    assert( TK_GE==TK_LE+2 );
    assert( TK_GT>TK_EQ );
    assert( TK_GT<TK_LE );
    assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
    pExpr->op = ((pExpr->op-TK_GT)^2)+TK_GT;
  }
  return 0;
}

/*
** Translate from TK_xx operator to WO_xx bitmask.
*/
static u16 operatorMask(int op){
  u16 c;

  aff1 = sqlite3ExprAffinity(pExpr->pLeft);
  aff2 = sqlite3ExprAffinity(pExpr->pRight);
  if( aff1!=aff2
   && (!sqlite3IsNumericAffinity(aff1) || !sqlite3IsNumericAffinity(aff2))
  ){
    return 0;
  }
  pColl = sqlite3ExprCompareCollSeq(pParse, pExpr);
  if( sqlite3IsBinary(pColl) ) return 1;
  return sqlite3ExprCollSeqMatch(pParse, pExpr->pLeft, pExpr->pRight);
}

/*
** Recursively walk the expressions of a SELECT statement and generate
** a bitmask indicating which tables are used in that expression

  SELECT (SELECT 5,6 UNION SELECT 3,4 ORDER BY 1) IN (SELECT 3,4);
  SELECT (SELECT 5,6 UNION SELECT 3,4 ORDER BY 1) IN (SELECT 5,6);
  SELECT (SELECT 3,4 UNION SELECT 5,6 ORDER BY 1 DESC) IN (SELECT 3,4);
  SELECT (SELECT 3,4 UNION SELECT 5,6 ORDER BY 1 DESC) IN (SELECT 5,6);
  SELECT (SELECT 5,6 UNION SELECT 3,4 ORDER BY 1 DESC) IN (SELECT 3,4);
  SELECT (SELECT 5,6 UNION SELECT 3,4 ORDER BY 1 DESC) IN (SELECT 5,6);
} {1 0 1 0 0 1 0 1}

# 2019-10-21 Ticket b47e3627ecaadbde
#
do_execsql_test 23.100 {
  DROP TABLE IF EXISTS t0;
  CREATE TABLE t0(aa COLLATE NOCASE, bb);
  INSERT INTO t0 VALUES('a', 'A');
  SELECT (+bb,1) >= (aa, 1), (aa,1)<=(+bb,1) FROM t0;
  SELECT 2 FROM t0 WHERE (+bb,1) >= (aa,1);
  SELECT 3 FROM t0 WHERE (aa,1) <= (+bb,1);
} {0 1 3}
do_execsql_test 23.110 {
  SELECT (SELECT +bb,1) >= (aa, 1), (aa,1)<=(SELECT +bb,1) FROM t0;
  SELECT 2 FROM t0 WHERE (SELECT +bb,1) >= (aa,1);
  SELECT 3 FROM t0 WHERE (aa,1) <= (SELECT +bb,1);
} {0 1 3}

finish_test

*/
int ParseFallback(int iToken){
#ifdef YYFALLBACK
  assert( iToken<(int)(sizeof(yyFallback)/sizeof(yyFallback[0])) );
  return yyFallback[iToken];
#else
  (void)iToken;

  return 0;
#endif
}