Fossil

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.38.0"
#define SQLITE_VERSION_NUMBER 3038000
#define SQLITE_SOURCE_ID      "2022-01-25 00:03:25 a8db69411b0d1275909adeb21027784ada17af24efe3a59ae0ae2a897659ff17"
#define SQLITE_SOURCE_ID      "2022-01-31 14:14:29 539cef5214446a7181614793e9cf323e95ba00ba0f888585b14b598dd2ff0808"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

** sqlite3_value objects and they can be used interchangeably.  However,
** for maximum code portability it is recommended that applications
** still make the distinction between protected and unprotected
** sqlite3_value objects even when not strictly required.
**
** ^The sqlite3_value objects that are passed as parameters into the
** implementation of [application-defined SQL functions] are protected.
** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
** are protected.
** ^The sqlite3_value object returned by
** [sqlite3_column_value()] is unprotected.
** Unprotected sqlite3_value objects may only be used as arguments
** to [sqlite3_result_value()], [sqlite3_bind_value()], and
** [sqlite3_value_dup()].
** The [sqlite3_value_blob | sqlite3_value_type()] family of
** interfaces require protected sqlite3_value objects.

#define SQLITE_INDEX_SCAN_UNIQUE      1     /* Scan visits at most 1 row */

/*
** CAPI3REF: Virtual Table Constraint Operator Codes
**
** These macros define the allowed values for the
** [sqlite3_index_info].aConstraint[].op field.  Each value represents
** an operator that is part of a constraint term in the wHERE clause of
** an operator that is part of a constraint term in the WHERE clause of
** a query that uses a [virtual table].
**
** ^The left-hand operand of the operator is given by the corresponding
** aConstraint[].iColumn field.  ^An iColumn of -1 indicates the left-hand
** operand is the rowid.
** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
** operators have no left-hand operand, and so for those operators the
** corresponding aConstraint[].iColumn is meaningless and should not be
** used.
**
** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
** value 255 are reserved to represent functions that are overloaded
** by the [xFindFunction|xFindFunction method] of the virtual table
** implementation.
**
** The right-hand operands for each constraint might be accessible using
** the [sqlite3_vtab_rhs_value()] interface.  Usually the right-hand
** operand is only available if it appears as a single constant literal
** in the input SQL.  If the right-hand operand is another column or an
** expression (even a constant expression) or a parameter, then the
** sqlite3_vtab_rhs_value() probably will not be able to extract it.
** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
** and hence calls to sqlite3_vtab_rhs_value() for those operators will
** always return SQLITE_NOTFOUND.
**
** The collating sequence to be used for comparison can be found using
** the [sqlite3_vtab_collation()] interface.  For most real-world virtual
** tables, the collating sequence of constraints does not matter (for example
** because the constraints are numeric) and so the sqlite3_vtab_collation()
** interface is no commonly needed.
*/
#define SQLITE_INDEX_CONSTRAINT_EQ         2
#define SQLITE_INDEX_CONSTRAINT_GT         4
#define SQLITE_INDEX_CONSTRAINT_LE         8
#define SQLITE_INDEX_CONSTRAINT_LT        16
#define SQLITE_INDEX_CONSTRAINT_GE        32
#define SQLITE_INDEX_CONSTRAINT_MATCH     64
#define SQLITE_INDEX_CONSTRAINT_LIKE      65
#define SQLITE_INDEX_CONSTRAINT_GLOB      66
#define SQLITE_INDEX_CONSTRAINT_REGEXP    67
#define SQLITE_INDEX_CONSTRAINT_NE        68
#define SQLITE_INDEX_CONSTRAINT_ISNOT     69
#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
#define SQLITE_INDEX_CONSTRAINT_ISNULL    71
#define SQLITE_INDEX_CONSTRAINT_IS        72
#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150
#define SQLITE_INDEX_CONSTRAINT_EQ          2
#define SQLITE_INDEX_CONSTRAINT_GT          4
#define SQLITE_INDEX_CONSTRAINT_LE          8
#define SQLITE_INDEX_CONSTRAINT_LT         16
#define SQLITE_INDEX_CONSTRAINT_GE         32
#define SQLITE_INDEX_CONSTRAINT_MATCH      64
#define SQLITE_INDEX_CONSTRAINT_LIKE       65
#define SQLITE_INDEX_CONSTRAINT_GLOB       66
#define SQLITE_INDEX_CONSTRAINT_REGEXP     67
#define SQLITE_INDEX_CONSTRAINT_NE         68
#define SQLITE_INDEX_CONSTRAINT_ISNOT      69
#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL  70
#define SQLITE_INDEX_CONSTRAINT_ISNULL     71
#define SQLITE_INDEX_CONSTRAINT_IS         72
#define SQLITE_INDEX_CONSTRAINT_LIMIT      73
#define SQLITE_INDEX_CONSTRAINT_OFFSET     74
#define SQLITE_INDEX_CONSTRAINT_FUNCTION  150

/*
** CAPI3REF: Register A Virtual Table Implementation
** METHOD: sqlite3
**
** ^These routines are used to register a new [virtual table module] name.
** ^Module names must be registered before

*/
SQLITE_API SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);

/*
** CAPI3REF: Determine if a virtual table query is DISTINCT
** METHOD: sqlite3_index_info
**
** This API may only be used from within an xBestIndex() callback. The
** results of calling it from outside of an xBestIndex() callback are
** undefined and probably harmful.
** This API may only be used from within an [xBestIndex|xBestIndex method]
** of a [virtual table] implementation. The result of calling this
** interface from outside of xBestIndex() is undefined and probably harmful.
**
** ^The sqlite3_vtab_distinct() returns an integer that is either 0, 1, or
** 2.  The integer returned by sqlite3_vtab_distinct() gives the virtual table
** additional information about how the query planner wants the output to be
** ordered.  As long as the virtual table can meet the ordering requirements
** of the query planner, it may set the "orderByConsumed" flag.
** ^The sqlite3_vtab_distinct() interface returns an integer that is
** either 0, 1, or 2.  The integer returned by sqlite3_vtab_distinct()
** gives the virtual table additional information about how the query
** planner wants the output to be ordered. As long as the virtual table
** can meet the ordering requirements of the query planner, it may set
** the "orderByConsumed" flag.
**
** <ol><li value="0"><p>
** ^If the sqlite3_vtab_distinct() interface returns 0, that means
** that the query planner needs the virtual table to return all rows in the
** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
** [sqlite3_index_info] object.  This is the default expectation.  If the
** virtual table outputs all rows in sorted order, then it is always safe for
** the xBestIndex method to set the "orderByConsumed" flag, regardless of
** what the return value from sqlite3_vtab_distinct().
** the return value from sqlite3_vtab_distinct().
** <li value="1"><p>
** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
** that the query planner does not need the rows to be returned in sorted order
** as long as all rows with the same values in all columns identified by the
** "aOrderBy" field are adjacent.)^  This mode is used when the query planner
** is doing a GROUP BY.
** <li value="2"><p>
** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
** that the query planner does not need the rows returned in any particular
** order, as long as rows with the same values in all "aOrderBy" columns
** are adjacent.)^  ^(Furthermore, only a single row for each particular
** combination of values in the columns identified by the "aOrderBy" field
** needs to be returned.)^  ^It is ok always for two or more rows with the same
** needs to be returned.)^  ^It is always ok for two or more rows with the same
** values in all "aOrderBy" columns to be returned, as long as all such rows
** are adjacent.  ^The virtual table may, if it chooses, omit extra rows
** that have the same value for all columns identified by "aOrderBy".
** ^However omitting the extra rows is optional.
** This mode is used for a DISTINCT query.
** </ol>
**

*/
SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info*);

/*
** CAPI3REF: Constraint values in xBestIndex()
** METHOD: sqlite3_index_info
**
** This API may only be used from within an xBestIndex() callback. The
** results of calling it from outside of an xBestIndex() callback are
** undefined and probably harmful.
** This API may only be used from within the [xBestIndex|xBestIndex method]
** of a [virtual table] implementation. The result of calling this interface
** from outside of an xBestIndex method are undefined and probably harmful.
**
** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
** the [xBestIndex] method of a [virtual table] implementation, with P being
** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
** J being a 0-based index into P->aConstraint[], then this routine
** attempts to set *V to be the value on the right-hand side of
** that constraint if the right-hand side is a known constant.  ^If the
** right-hand side of the constraint is not known, then *V is set to a NULL
** pointer.  ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
** attempts to set *V to the value of the right-hand operand of
** that constraint if the right-hand operand is known.  ^If the
** right-hand operand is not known, then *V is set to a NULL pointer.
** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
** and only if *V is set to a value.  ^The sqlite3_vtab_rhs_value(P,J,V)
** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
** constraint is not available.  ^The sqlite3_vtab_rhs_value() interface
** can return an result code other than SQLITE_OK or SQLITE_NOTFOUND if
** something goes wrong.
**
** The sqlite3_vtab_rhs_value() interface is usually only successful if
** the right-hand operand of a constraint is a literal value in the original
** SQL statement.  If the right-hand operand is an expression or a reference
** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
** will probably return [SQLITE_NOTFOUND].
**
** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand.  For such
** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
**
** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
** ^The sqlite3_value object returned in *V remains valid for the duration of
** the xBestIndex method code.  ^When xBestIndex returns, the sqlite3_value
** object returned by sqlite3_vtab_rhs_value() is automatically deallocated.
** and remains valid for the duration of the xBestIndex method call.
** ^When xBestIndex returns, the sqlite3_value object returned by
** sqlite3_vtab_rhs_value() is automatically deallocated.
**
** The "_rhs_" in the name of this routine is an appreviation for
** "Right-Hand Side".
*/
SQLITE_API int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);

/*
** CAPI3REF: Conflict resolution modes
** KEYWORDS: {conflict resolution mode}
**

#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY)
SQLITE_PRIVATE Expr *sqlite3LimitWhere(Parse*,SrcList*,Expr*,ExprList*,Expr*,char*);
#endif
SQLITE_PRIVATE void sqlite3CodeChangeCount(Vdbe*,int,const char*);
SQLITE_PRIVATE void sqlite3DeleteFrom(Parse*, SrcList*, Expr*, ExprList*, Expr*);
SQLITE_PRIVATE void sqlite3Update(Parse*, SrcList*, ExprList*,Expr*,int,ExprList*,Expr*,
                   Upsert*);
SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(Parse*,SrcList*,Expr*,ExprList*,ExprList*,u16,int);
SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(Parse*,SrcList*,Expr*,ExprList*,
                             ExprList*,Select*,u16,int);
SQLITE_PRIVATE void sqlite3WhereEnd(WhereInfo*);
SQLITE_PRIVATE LogEst sqlite3WhereOutputRowCount(WhereInfo*);
SQLITE_PRIVATE int sqlite3WhereIsDistinct(WhereInfo*);
SQLITE_PRIVATE int sqlite3WhereIsOrdered(WhereInfo*);
SQLITE_PRIVATE int sqlite3WhereOrderByLimitOptLabel(WhereInfo*);
SQLITE_PRIVATE void sqlite3WhereMinMaxOptEarlyOut(Vdbe*,WhereInfo*);
SQLITE_PRIVATE int sqlite3WhereIsSorted(WhereInfo*);

      **
      ** Always interpret the prior number as a julian-day value.  If this
      ** is not the first modifier, or if the prior argument is not a numeric
      ** value in the allowed range of julian day numbers understood by
      ** SQLite (0..5373484.5) then the result will be NULL.
      */
      if( sqlite3_stricmp(z, "julianday")==0 ){
        if( idx>1 ) return 1;
        if( idx>1 ) return 1;  /* IMP: R-31176-64601 */
        if( p->validJD && p->rawS ){
          rc = 0;
          p->rawS = 0;
        }
      }
      break;
    }

      /*
      **    unixepoch
      **
      ** Treat the current value of p->s as the number of
      ** seconds since 1970.  Convert to a real julian day number.
      */
      if( sqlite3_stricmp(z, "unixepoch")==0 && p->rawS ){
        if( idx>1 ) return 1;  /* IMP: R-49255-55373 */
        r = p->s*1000.0 + 210866760000000.0;
        if( r>=0.0 && r<464269060800000.0 ){
          clearYMD_HMS_TZ(p);
          p->iJD = (sqlite3_int64)(r + 0.5);
          p->validJD = 1;
          p->rawS = 0;
          rc = 0;

*/
static Btree *findBtree(sqlite3 *pErrorDb, sqlite3 *pDb, const char *zDb){
  int i = sqlite3FindDbName(pDb, zDb);

  if( i==1 ){
    Parse sParse;
    int rc = 0;
    sqlite3ParseObjectInit(&sParse,pErrorDb);
    sqlite3ParseObjectInit(&sParse,pDb);
    if( sqlite3OpenTempDatabase(&sParse) ){
      sqlite3ErrorWithMsg(pErrorDb, sParse.rc, "%s", sParse.zErrMsg);
      rc = SQLITE_ERROR;
    }
    sqlite3DbFree(pErrorDb, sParse.zErrMsg);
    sqlite3ParseObjectReset(&sParse);
    if( rc ){

  sqlite3_value *pVal = 0;
  int negInt = 1;
  const char *zNeg = "";
  int rc = SQLITE_OK;

  assert( pExpr!=0 );
  while( (op = pExpr->op)==TK_UPLUS || op==TK_SPAN ) pExpr = pExpr->pLeft;
#if defined(SQLITE_ENABLE_STAT4)
  if( op==TK_REGISTER ) op = pExpr->op2;
#else
  if( NEVER(op==TK_REGISTER) ) op = pExpr->op2;
#endif

  /* Compressed expressions only appear when parsing the DEFAULT clause
  ** on a table column definition, and hence only when pCtx==0.  This
  ** check ensures that an EP_TokenOnly expression is never passed down
  ** into valueFromFunction(). */
  assert( (pExpr->flags & EP_TokenOnly)==0 || pCtx==0 );

    ** to be deleted, based on the WHERE clause. Set variable eOnePass
    ** to indicate the strategy used to implement this delete:
    **
    **  ONEPASS_OFF:    Two-pass approach - use a FIFO for rowids/PK values.
    **  ONEPASS_SINGLE: One-pass approach - at most one row deleted.
    **  ONEPASS_MULTI:  One-pass approach - any number of rows may be deleted.
    */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, wcf, iTabCur+1);
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0,0,wcf,iTabCur+1);
    if( pWInfo==0 ) goto delete_from_cleanup;
    eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
    assert( IsVirtual(pTab)==0 || eOnePass!=ONEPASS_MULTI );
    assert( IsVirtual(pTab) || bComplex || eOnePass!=ONEPASS_OFF );
    if( eOnePass!=ONEPASS_SINGLE ) sqlite3MultiWrite(pParse);
    if( sqlite3WhereUsesDeferredSeek(pWInfo) ){
      sqlite3VdbeAddOp1(v, OP_FinishSeek, iTabCur);

  sNameContext.pParse = pParse;
  sqlite3ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. For each row found, increment either the deferred or immediate
  ** foreign key constraint counter. */
  if( pParse->nErr==0 ){
    pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0);
    pWInfo = sqlite3WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0, 0);
    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
    if( pWInfo ){
      sqlite3WhereEnd(pWInfo);
    }
  }

  /* Clean up the WHERE clause constructed above. */

SQLITE_PRIVATE void sqlite3ParseObjectInit(Parse *pParse, sqlite3 *db){
  memset(PARSE_HDR(pParse), 0, PARSE_HDR_SZ);
  memset(PARSE_TAIL(pParse), 0, PARSE_TAIL_SZ);
  assert( db->pParse!=pParse );
  pParse->pOuterParse = db->pParse;
  db->pParse = pParse;
  pParse->db = db;
  if( db->mallocFailed ) sqlite3ErrorMsg(pParse, "out of memory");
}

/*
** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
*/
static int sqlite3Prepare(
  sqlite3 *db,              /* Database handle. */

  memset(PARSE_HDR(&sParse), 0, PARSE_HDR_SZ);
  memset(PARSE_TAIL(&sParse), 0, PARSE_TAIL_SZ);
  sParse.pOuterParse = db->pParse;
  db->pParse = &sParse;
  sParse.db = db;
  sParse.pReprepare = pReprepare;
  assert( ppStmt && *ppStmt==0 );
  /* assert( !db->mallocFailed ); // not true with SQLITE_USE_ALLOCA */
  if( db->mallocFailed ) sqlite3ErrorMsg(&sParse, "out of memory");
  assert( sqlite3_mutex_held(db->mutex) );

  /* For a long-term use prepared statement avoid the use of
  ** lookaside memory.
  */
  if( prepFlags & SQLITE_PREPARE_PERSISTENT ){
    sParse.disableLookaside++;

#endif
    assert( WHERE_USE_LIMIT==SF_FixedLimit );


    /* Begin the database scan. */
    SELECTTRACE(1,pParse,p,("WhereBegin\n"));
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, sSort.pOrderBy,
                               p->pEList, wctrlFlags, p->nSelectRow);
                               p->pEList, p, wctrlFlags, p->nSelectRow);
    if( pWInfo==0 ) goto select_end;
    if( sqlite3WhereOutputRowCount(pWInfo) < p->nSelectRow ){
      p->nSelectRow = sqlite3WhereOutputRowCount(pWInfo);
    }
    if( sDistinct.isTnct && sqlite3WhereIsDistinct(pWInfo) ){
      sDistinct.eTnctType = sqlite3WhereIsDistinct(pWInfo);
    }

      ** This might involve two separate loops with an OP_Sort in between, or
      ** it might be a single loop that uses an index to extract information
      ** in the right order to begin with.
      */
      sqlite3VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      SELECTTRACE(1,pParse,p,("WhereBegin\n"));
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pGroupBy, pDistinct,
          WHERE_GROUPBY | (orderByGrp ? WHERE_SORTBYGROUP : 0) | distFlag, 0
          0, (WHERE_GROUPBY|(orderByGrp ? WHERE_SORTBYGROUP : 0)|distFlag), 0
      );
      if( pWInfo==0 ){
        sqlite3ExprListDelete(db, pDistinct);
        goto select_end;
      }
      eDist = sqlite3WhereIsDistinct(pWInfo);
      SELECTTRACE(1,pParse,p,("WhereBegin returns\n"));

        ** be an appropriate ORDER BY expression for the optimization.
        */
        assert( minMaxFlag==WHERE_ORDERBY_NORMAL || pMinMaxOrderBy!=0 );
        assert( pMinMaxOrderBy==0 || pMinMaxOrderBy->nExpr==1 );

        SELECTTRACE(1,pParse,p,("WhereBegin\n"));
        pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, pMinMaxOrderBy,
                                   pDistinct, minMaxFlag|distFlag, 0);
                                   pDistinct, 0, minMaxFlag|distFlag, 0);
        if( pWInfo==0 ){
          goto select_end;
        }
        SELECTTRACE(1,pParse,p,("WhereBegin returns\n"));
        eDist = sqlite3WhereIsDistinct(pWInfo);
        updateAccumulator(pParse, regAcc, pAggInfo, eDist);
        if( eDist!=WHERE_DISTINCT_NOOP ){

      ** be deleted as a result of REPLACE conflict handling. Any of these
      ** things might disturb a cursor being used to scan through the table
      ** or index, causing a single-pass approach to malfunction.  */
      flags = WHERE_ONEPASS_DESIRED;
      if( !pParse->nested && !pTrigger && !hasFK && !chngKey && !bReplace ){
        flags |= WHERE_ONEPASS_MULTIROW;
      }
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, flags,iIdxCur);
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere,0,0,0,flags,iIdxCur);
      if( pWInfo==0 ) goto update_cleanup;

      /* A one-pass strategy that might update more than one row may not
      ** be used if any column of the index used for the scan is being
      ** updated. Otherwise, if there is an index on "b", statements like
      ** the following could create an infinite loop:
      **

    sqlite3ExprListDelete(db, pList);
    eOnePass = ONEPASS_OFF;
  }else{
    regRec = ++pParse->nMem;
    regRowid = ++pParse->nMem;

    /* Start scanning the virtual table */
    pWInfo = sqlite3WhereBegin(pParse, pSrc,pWhere,0,0,WHERE_ONEPASS_DESIRED,0);
    pWInfo = sqlite3WhereBegin(
        pParse, pSrc, pWhere, 0, 0, 0, WHERE_ONEPASS_DESIRED, 0
    );
    if( pWInfo==0 ) return;

    /* Populate the argument registers. */
    for(i=0; i<pTab->nCol; i++){
      assert( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)==0 );
      if( aXRef[i]>=0 ){
        sqlite3ExprCode(pParse, pChanges->a[aXRef[i]].pExpr, regArg+2+i);

      u16 nBtm;              /* Size of BTM vector */
      u16 nTop;              /* Size of TOP vector */
      u16 nDistinctCol;      /* Index columns used to sort for DISTINCT */
      Index *pIndex;         /* Index used, or NULL */
    } btree;
    struct {               /* Information for virtual tables */
      int idxNum;            /* Index number */
      u8 needFree;           /* True if sqlite3_free(idxStr) is needed */
      u8 needFree : 1;       /* True if sqlite3_free(idxStr) is needed */
      u8 bOmitOffset : 1;    /* True to let virtual table handle offset */
      i8 isOrdered;          /* True if satisfies ORDER BY */
      u16 omitMask;          /* Terms that may be omitted */
      char *idxStr;          /* Index identifier string */
    } vtab;
  } u;
  u32 wsFlags;          /* WHERE_* flags describing the plan */
  u16 nLTerm;           /* Number of entries in aLTerm[] */

*/
struct WhereInfo {
  Parse *pParse;            /* Parsing and code generating context */
  SrcList *pTabList;        /* List of tables in the join */
  ExprList *pOrderBy;       /* The ORDER BY clause or NULL */
  ExprList *pResultSet;     /* Result set of the query */
  Expr *pWhere;             /* The complete WHERE clause */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  Select *pLimit;           /* Used to access LIMIT expr/registers for vtabs */
#endif
  int aiCurOnePass[2];      /* OP_OpenWrite cursors for the ONEPASS opt */
  int iContinue;            /* Jump here to continue with next record */
  int iBreak;               /* Jump here to break out of the loop */
  int savedNQueryLoop;      /* pParse->nQueryLoop outside the WHERE loop */
  u16 wctrlFlags;           /* Flags originally passed to sqlite3WhereBegin() */
  LogEst iLimit;            /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */
  u8 nLevel;                /* Number of nested loop */

  Bitmask notReady     /* Which tables are currently available */
);

/* whereexpr.c: */
SQLITE_PRIVATE void sqlite3WhereClauseInit(WhereClause*,WhereInfo*);
SQLITE_PRIVATE void sqlite3WhereClauseClear(WhereClause*);
SQLITE_PRIVATE void sqlite3WhereSplit(WhereClause*,Expr*,u8);
SQLITE_PRIVATE void sqlite3WhereAddLimit(WhereClause*, Select*);
SQLITE_PRIVATE Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*);
SQLITE_PRIVATE Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*);
SQLITE_PRIVATE Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*);
SQLITE_PRIVATE void sqlite3WhereExprAnalyze(SrcList*, WhereClause*);
SQLITE_PRIVATE void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*);

#define WHERE_PARTIALIDX   0x00020000  /* The automatic index is partial */
#define WHERE_IN_EARLYOUT  0x00040000  /* Perhaps quit IN loops early */
#define WHERE_BIGNULL_SORT 0x00080000  /* Column nEq of index is BIGNULL */
#define WHERE_IN_SEEKSCAN  0x00100000  /* Seek-scan optimization for IN */
#define WHERE_TRANSCONS    0x00200000  /* Uses a transitive constraint */
#define WHERE_BLOOMFILTER  0x00400000  /* Consider using a Bloom-filter */
#define WHERE_SELFCULL     0x00800000  /* nOut reduced by extra WHERE terms */
#define WHERE_OMIT_OFFSET  0x01000000  /* Set offset counter to zero */

#endif /* !defined(SQLITE_WHEREINT_H) */

/************** End of whereInt.h ********************************************/
/************** Continuing where we left off in wherecode.c ******************/

#ifndef SQLITE_OMIT_EXPLAIN

      if( NEVER(pTerm==0) ) continue;
      if( pTerm->eOperator & WO_IN ){
        codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, iTarget);
        addrNotFound = pLevel->addrNxt;
      }else{
        Expr *pRight = pTerm->pExpr->pRight;
        codeExprOrVector(pParse, pRight, iTarget, 1);
        if( pTerm->eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET
         && pLoop->u.vtab.bOmitOffset
        ){
          assert( pTerm->eOperator==WO_AUX );
          assert( pWInfo->pLimit!=0 );
          assert( pWInfo->pLimit->iOffset>0 );
          sqlite3VdbeAddOp2(v, OP_Integer, 0, pWInfo->pLimit->iOffset);
          VdbeComment((v,"Zero OFFSET counter"));
        }
      }
    }
    sqlite3VdbeAddOp2(v, OP_Integer, pLoop->u.vtab.idxNum, iReg);
    sqlite3VdbeAddOp2(v, OP_Integer, nConstraint, iReg+1);
    sqlite3VdbeAddOp4(v, OP_VFilter, iCur, addrNotFound, iReg,
                      pLoop->u.vtab.idxStr,
                      pLoop->u.vtab.needFree ? P4_DYNAMIC : P4_STATIC);

        if( pAndExpr ){
          pAndExpr->pLeft = pOrExpr;
          pOrExpr = pAndExpr;
        }
        /* Loop through table entries that match term pOrTerm. */
        ExplainQueryPlan((pParse, 1, "INDEX %d", ii+1));
        WHERETRACE(0xffff, ("Subplan for OR-clause:\n"));
        pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
        pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0, 0,
                                      WHERE_OR_SUBCLAUSE, iCovCur);
        assert( pSubWInfo || pParse->nErr );
        if( pSubWInfo ){
          WhereLoop *pSubLoop;
          int addrExplain = sqlite3WhereExplainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], 0
          );

  /* If there is a vector == or IS term - e.g. "(a, b) == (?, ?)" - create
  ** new terms for each component comparison - "a = ?" and "b = ?".  The
  ** new terms completely replace the original vector comparison, which is
  ** no longer used.
  **
  ** This is only required if at least one side of the comparison operation
  ** is not a sub-select.  */
  ** is not a sub-select.
  **
  ** tag-20220128a
  */
  if( (pExpr->op==TK_EQ || pExpr->op==TK_IS)
   && (nLeft = sqlite3ExprVectorSize(pExpr->pLeft))>1
   && sqlite3ExprVectorSize(pExpr->pRight)==nLeft
   && ( (pExpr->pLeft->flags & EP_xIsSelect)==0
     || (pExpr->pRight->flags & EP_xIsSelect)==0)
   && pWC->op==TK_AND
  ){

  if( pE2->op!=op ){
    whereClauseInsert(pWC, pExpr, 0);
  }else{
    sqlite3WhereSplit(pWC, pE2->pLeft, op);
    sqlite3WhereSplit(pWC, pE2->pRight, op);
  }
}

/*
** Add either a LIMIT (if eMatchOp==SQLITE_INDEX_CONSTRAINT_LIMIT) or
** OFFSET (if eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET) term to the
** where-clause passed as the first argument. The value for the term
** is found in register iReg.
**
** In the common case where the value is a simple integer
** (example: "LIMIT 5 OFFSET 10") then the expression codes as a
** TK_INTEGER so that it will be available to sqlite3_vtab_rhs_value().
** If not, then it codes as a TK_REGISTER expression.
*/
void whereAddLimitExpr(
  WhereClause *pWC,   /* Add the constraint to this WHERE clause */
  int iReg,           /* Register that will hold value of the limit/offset */
  Expr *pExpr,        /* Expression that defines the limit/offset */
  int iCsr,           /* Cursor to which the constraint applies */
  int eMatchOp        /* SQLITE_INDEX_CONSTRAINT_LIMIT or _OFFSET */
){
  Parse *pParse = pWC->pWInfo->pParse;
  sqlite3 *db = pParse->db;
  Expr *pNew;
  int iVal = 0;

  if( sqlite3ExprIsInteger(pExpr, &iVal) && iVal>=0 ){
    Expr *pVal = sqlite3Expr(db, TK_INTEGER, 0);
    if( pVal==0 ) return;
    ExprSetProperty(pVal, EP_IntValue);
    pVal->u.iValue = iVal;
    pNew = sqlite3PExpr(pParse, TK_MATCH, 0, pVal);
  }else{
    Expr *pVal = sqlite3Expr(db, TK_REGISTER, 0);
    if( pVal==0 ) return;
    pVal->iTable = iReg;
    pNew = sqlite3PExpr(pParse, TK_MATCH, 0, pVal);
  }
  if( pNew ){
    WhereTerm *pTerm;
    int idx;
    idx = whereClauseInsert(pWC, pNew, TERM_DYNAMIC|TERM_VIRTUAL);
    pTerm = &pWC->a[idx];
    pTerm->leftCursor = iCsr;
    pTerm->eOperator = WO_AUX;
    pTerm->eMatchOp = eMatchOp;
  }
}

/*
** Possibly add terms corresponding to the LIMIT and OFFSET clauses of the
** SELECT statement passed as the second argument. These terms are only
** added if:
**
**   1. The SELECT statement has a LIMIT clause, and
**   2. The SELECT statement is not an aggregate or DISTINCT query, and
**   3. The SELECT statement has exactly one object in its from clause, and
**      that object is a virtual table, and
**   4. There are no terms in the WHERE clause that will not be passed
**      to the virtual table xBestIndex method.
**   5. The ORDER BY clause, if any, will be made available to the xBestIndex
**      method.
**
** LIMIT and OFFSET terms are ignored by most of the planner code. They
** exist only so that they may be passed to the xBestIndex method of the
** single virtual table in the FROM clause of the SELECT.
*/
SQLITE_PRIVATE void sqlite3WhereAddLimit(WhereClause *pWC, Select *p){
  assert( p==0 || (p->pGroupBy==0 && (p->selFlags & SF_Aggregate)==0) );
  if( (p && p->pLimit)                                          /* 1 */
   && (p->selFlags & (SF_Distinct|SF_Aggregate))==0             /* 2 */
   && (p->pSrc->nSrc==1 && IsVirtual(p->pSrc->a[0].pTab))       /* 3 */
  ){
    ExprList *pOrderBy = p->pOrderBy;
    int iCsr = p->pSrc->a[0].iCursor;
    int ii;

    /* Check condition (4). Return early if it is not met. */
    for(ii=0; ii<pWC->nTerm; ii++){
      if( pWC->a[ii].wtFlags & TERM_CODED ){
        /* This term is a vector operation that has been decomposed into
        ** other, subsequent terms.  It can be ignored. See tag-20220128a */
        assert( pWC->a[ii].wtFlags & TERM_VIRTUAL );
        assert( pWC->a[ii].eOperator==0 );
        continue;
      }
      if( pWC->a[ii].leftCursor!=iCsr ) return;
    }

    /* Check condition (5). Return early if it is not met. */
    if( pOrderBy ){
      for(ii=0; ii<pOrderBy->nExpr; ii++){
        Expr *pExpr = pOrderBy->a[ii].pExpr;
        if( pExpr->op!=TK_COLUMN ) return;
        if( pExpr->iTable!=iCsr ) return;
        if( pOrderBy->a[ii].sortFlags & KEYINFO_ORDER_BIGNULL ) return;
      }
    }

    /* All conditions are met. Add the terms to the where-clause object. */
    assert( p->pLimit->op==TK_LIMIT );
    whereAddLimitExpr(pWC, p->iLimit, p->pLimit->pLeft,
                      iCsr, SQLITE_INDEX_CONSTRAINT_LIMIT);
    if( p->iOffset>0 ){
      whereAddLimitExpr(pWC, p->iOffset, p->pLimit->pRight,
                        iCsr, SQLITE_INDEX_CONSTRAINT_OFFSET);
    }
  }
}

/*
** Initialize a preallocated WhereClause structure.
*/
SQLITE_PRIVATE void sqlite3WhereClauseInit(
  WhereClause *pWC,        /* The WhereClause to be initialized */
  WhereInfo *pWInfo        /* The WHERE processing context */

    int i;
    /* Verify that every term past pWC->nBase is virtual */
    for(i=pWC->nBase; i<pWC->nTerm; i++){
      assert( (pWC->a[i].wtFlags & TERM_VIRTUAL)!=0 );
    }
#endif
    while(1){
      assert( a->eMatchOp==0 || a->eOperator==WO_AUX );
      if( a->wtFlags & TERM_DYNAMIC ){
        sqlite3ExprDelete(db, a->pExpr);
      }
      if( a->wtFlags & (TERM_ORINFO|TERM_ANDINFO) ){
        if( a->wtFlags & TERM_ORINFO ){
          assert( (a->wtFlags & TERM_ANDINFO)==0 );
          whereOrInfoDelete(db, a->u.pOrInfo);

    }
    pColRef = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0);
    if( pColRef==0 ) return;
    pColRef->iTable = pItem->iCursor;
    pColRef->iColumn = k++;
    assert( ExprUseYTab(pColRef) );
    pColRef->y.pTab = pTab;
    pItem->colUsed |= sqlite3ExprColUsed(pColRef);
    pRhs = sqlite3PExpr(pParse, TK_UPLUS,
        sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0), 0);
    pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef, pRhs);
    if( pItem->fg.jointype & JT_LEFT ){
      sqlite3SetJoinExpr(pTerm, pItem->iCursor);
    }
    whereClauseInsert(pWC, pTerm, TERM_DYNAMIC);

    pBuilder->pRec = 0;
#endif
  }
  return rc;
}

#ifndef SQLITE_OMIT_VIRTUALTABLE

/*
** Return true if pTerm is a virtual table LIMIT or OFFSET term.
*/
static int isLimitTerm(WhereTerm *pTerm){
  assert( pTerm->eOperator==WO_AUX || pTerm->eMatchOp==0 );
  return pTerm->eMatchOp>=SQLITE_INDEX_CONSTRAINT_LIMIT
      && pTerm->eMatchOp<=SQLITE_INDEX_CONSTRAINT_OFFSET;
}

/*
** Argument pIdxInfo is already populated with all constraints that may
** be used by the virtual table identified by pBuilder->pNew->iTab. This
** function marks a subset of those constraints usable, invokes the
** xBestIndex method and adds the returned plan to pBuilder.
**

static int whereLoopAddVirtualOne(
  WhereLoopBuilder *pBuilder,
  Bitmask mPrereq,                /* Mask of tables that must be used. */
  Bitmask mUsable,                /* Mask of usable tables */
  u16 mExclude,                   /* Exclude terms using these operators */
  sqlite3_index_info *pIdxInfo,   /* Populated object for xBestIndex */
  u16 mNoOmit,                    /* Do not omit these constraints */
  int *pbIn                       /* OUT: True if plan uses an IN(...) op */
  int *pbIn,                      /* OUT: True if plan uses an IN(...) op */
  int *pbRetryLimit               /* OUT: Retry without LIMIT/OFFSET */
){
  WhereClause *pWC = pBuilder->pWC;
  struct sqlite3_index_constraint *pIdxCons;
  struct sqlite3_index_constraint_usage *pUsage = pIdxInfo->aConstraintUsage;
  int i;
  int mxTerm;
  int rc = SQLITE_OK;

  ** arguments mUsable and mExclude. */
  pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
  for(i=0; i<nConstraint; i++, pIdxCons++){
    WhereTerm *pTerm = &pWC->a[pIdxCons->iTermOffset];
    pIdxCons->usable = 0;
    if( (pTerm->prereqRight & mUsable)==pTerm->prereqRight
     && (pTerm->eOperator & mExclude)==0
     && (pbRetryLimit || !isLimitTerm(pTerm))
    ){
      pIdxCons->usable = 1;
    }
  }

  /* Initialize the output fields of the sqlite3_index_info structure */
  memset(pUsage, 0, sizeof(pUsage[0])*nConstraint);

      return SQLITE_OK;
    }
    return rc;
  }

  mxTerm = -1;
  assert( pNew->nLSlot>=nConstraint );
  for(i=0; i<nConstraint; i++) pNew->aLTerm[i] = 0;
  pNew->u.vtab.omitMask = 0;
  memset(pNew->aLTerm, 0, sizeof(pNew->aLTerm[0])*nConstraint );
  memset(&pNew->u.vtab, 0, sizeof(pNew->u.vtab));
  pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
  for(i=0; i<nConstraint; i++, pIdxCons++){
    int iTerm;
    if( (iTerm = pUsage[i].argvIndex - 1)>=0 ){
      WhereTerm *pTerm;
      int j = pIdxCons->iTermOffset;
      if( iTerm>=nConstraint

      if( pUsage[i].omit ){
        if( i<16 && ((1<<i)&mNoOmit)==0 ){
          testcase( i!=iTerm );
          pNew->u.vtab.omitMask |= 1<<iTerm;
        }else{
          testcase( i!=iTerm );
        }
        if( pTerm->eMatchOp==SQLITE_INDEX_CONSTRAINT_OFFSET ){
          pNew->u.vtab.bOmitOffset = 1;
        }
      }
      if( (pTerm->eOperator & WO_IN)!=0 ){
        /* A virtual table that is constrained by an IN clause may not
        ** consume the ORDER BY clause because (1) the order of IN terms
        ** is not necessarily related to the order of output terms and
        ** (2) Multiple outputs from a single IN value will not merge
        ** together.  */
        pIdxInfo->orderByConsumed = 0;
        pIdxInfo->idxFlags &= ~SQLITE_INDEX_SCAN_UNIQUE;
        *pbIn = 1; assert( (mExclude & WO_IN)==0 );
      }

      if( isLimitTerm(pTerm) && *pbIn ){
        /* If there is an IN(...) term handled as an == (separate call to
        ** xFilter for each value on the RHS of the IN) and a LIMIT or
        ** OFFSET term handled as well, the plan is unusable. Set output
        ** variable *pbRetryLimit to true to tell the caller to retry with
        ** LIMIT and OFFSET disabled. */
        if( pIdxInfo->needToFreeIdxStr ){
          sqlite3_free(pIdxInfo->idxStr);
          pIdxInfo->idxStr = 0;
          pIdxInfo->needToFreeIdxStr = 0;
        }
        *pbRetryLimit = 1;
        return SQLITE_OK;
      }
    }
  }

  pNew->nLTerm = mxTerm+1;
  for(i=0; i<=mxTerm; i++){
    if( pNew->aLTerm[i]==0 ){
      /* The non-zero argvIdx values must be contiguous.  Raise an

  SrcItem *pSrc;               /* The FROM clause term to search */
  sqlite3_index_info *p;       /* Object to pass to xBestIndex() */
  int nConstraint;             /* Number of constraints in p */
  int bIn;                     /* True if plan uses IN(...) operator */
  WhereLoop *pNew;
  Bitmask mBest;               /* Tables used by best possible plan */
  u16 mNoOmit;
  int bRetry = 0;              /* True to retry with LIMIT/OFFSET disabled */

  assert( (mPrereq & mUnusable)==0 );
  pWInfo = pBuilder->pWInfo;
  pParse = pWInfo->pParse;
  pWC = pBuilder->pWC;
  pNew = pBuilder->pNew;
  pSrc = &pWInfo->pTabList->a[pNew->iTab];

    freeIndexInfo(pParse->db, p);
    return SQLITE_NOMEM_BKPT;
  }

  /* First call xBestIndex() with all constraints usable. */
  WHERETRACE(0x800, ("BEGIN %s.addVirtual()\n", pSrc->pTab->zName));
  WHERETRACE(0x40, ("  VirtualOne: all usable\n"));
  rc = whereLoopAddVirtualOne(pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn);
  rc = whereLoopAddVirtualOne(
      pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn, &bRetry
  );
  if( bRetry ){
    assert( rc==SQLITE_OK );
    rc = whereLoopAddVirtualOne(
        pBuilder, mPrereq, ALLBITS, 0, p, mNoOmit, &bIn, 0
    );
  }

  /* If the call to xBestIndex() with all terms enabled produced a plan
  ** that does not require any source tables (IOW: a plan with mBest==0)
  ** and does not use an IN(...) operator, then there is no point in making
  ** any further calls to xBestIndex() since they will all return the same
  ** result (if the xBestIndex() implementation is sane). */
  if( rc==SQLITE_OK && ((mBest = (pNew->prereq & ~mPrereq))!=0 || bIn) ){
    int seenZero = 0;             /* True if a plan with no prereqs seen */
    int seenZeroNoIN = 0;         /* Plan with no prereqs and no IN(...) seen */
    Bitmask mPrev = 0;
    Bitmask mBestNoIn = 0;

    /* If the plan produced by the earlier call uses an IN(...) term, call
    ** xBestIndex again, this time with IN(...) terms disabled. */
    if( bIn ){
      WHERETRACE(0x40, ("  VirtualOne: all usable w/o IN\n"));
      rc = whereLoopAddVirtualOne(
          pBuilder, mPrereq, ALLBITS, WO_IN, p, mNoOmit, &bIn);
          pBuilder, mPrereq, ALLBITS, WO_IN, p, mNoOmit, &bIn, 0);
      assert( bIn==0 );
      mBestNoIn = pNew->prereq & ~mPrereq;
      if( mBestNoIn==0 ){
        seenZero = 1;
        seenZeroNoIN = 1;
      }
    }

      }
      mPrev = mNext;
      if( mNext==ALLBITS ) break;
      if( mNext==mBest || mNext==mBestNoIn ) continue;
      WHERETRACE(0x40, ("  VirtualOne: mPrev=%04llx mNext=%04llx\n",
                       (sqlite3_uint64)mPrev, (sqlite3_uint64)mNext));
      rc = whereLoopAddVirtualOne(
          pBuilder, mPrereq, mNext|mPrereq, 0, p, mNoOmit, &bIn);
          pBuilder, mPrereq, mNext|mPrereq, 0, p, mNoOmit, &bIn, 0);
      if( pNew->prereq==mPrereq ){
        seenZero = 1;
        if( bIn==0 ) seenZeroNoIN = 1;
      }
    }

    /* If the calls to xBestIndex() in the above loop did not find a plan
    ** that requires no source tables at all (i.e. one guaranteed to be
    ** usable), make a call here with all source tables disabled */
    if( rc==SQLITE_OK && seenZero==0 ){
      WHERETRACE(0x40, ("  VirtualOne: all disabled\n"));
      rc = whereLoopAddVirtualOne(
          pBuilder, mPrereq, mPrereq, 0, p, mNoOmit, &bIn);
          pBuilder, mPrereq, mPrereq, 0, p, mNoOmit, &bIn, 0);
      if( bIn==0 ) seenZeroNoIN = 1;
    }

    /* If the calls to xBestIndex() have so far failed to find a plan
    ** that requires no source tables at all and does not use an IN(...)
    ** operator, make a final call to obtain one here.  */
    if( rc==SQLITE_OK && seenZeroNoIN==0 ){
      WHERETRACE(0x40, ("  VirtualOne: all disabled and w/o IN\n"));
      rc = whereLoopAddVirtualOne(
          pBuilder, mPrereq, mPrereq, WO_IN, p, mNoOmit, &bIn);
          pBuilder, mPrereq, mPrereq, WO_IN, p, mNoOmit, &bIn, 0);
    }
  }

  if( p->needToFreeIdxStr ) sqlite3_free(p->idxStr);
  freeIndexInfo(pParse->db, p);
  WHERETRACE(0x800, ("END %s.addVirtual(), rc=%d\n", pSrc->pTab->zName, rc));
  return rc;

*/
SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
  Parse *pParse,          /* The parser context */
  SrcList *pTabList,      /* FROM clause: A list of all tables to be scanned */
  Expr *pWhere,           /* The WHERE clause */
  ExprList *pOrderBy,     /* An ORDER BY (or GROUP BY) clause, or NULL */
  ExprList *pResultSet,   /* Query result set.  Req'd for DISTINCT */
  Select *pLimit,         /* Use this LIMIT/OFFSET clause, if any */
  u16 wctrlFlags,         /* The WHERE_* flags defined in sqliteInt.h */
  int iAuxArg             /* If WHERE_OR_SUBCLAUSE is set, index cursor number
                          ** If WHERE_USE_LIMIT, then the limit amount */
){
  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
  int nTabList;              /* Number of elements in pTabList */
  WhereInfo *pWInfo;         /* Will become the return value of this function */

  pWInfo->pResultSet = pResultSet;
  pWInfo->aiCurOnePass[0] = pWInfo->aiCurOnePass[1] = -1;
  pWInfo->nLevel = nTabList;
  pWInfo->iBreak = pWInfo->iContinue = sqlite3VdbeMakeLabel(pParse);
  pWInfo->wctrlFlags = wctrlFlags;
  pWInfo->iLimit = iAuxArg;
  pWInfo->savedNQueryLoop = pParse->nQueryLoop;
#ifndef SQLITE_OMIT_VIRTUALTABLE
  pWInfo->pLimit = pLimit;
#endif
  memset(&pWInfo->nOBSat, 0,
         offsetof(WhereInfo,sWC) - offsetof(WhereInfo,nOBSat));
  memset(&pWInfo->a[0], 0, sizeof(WhereLoop)+nTabList*sizeof(WhereLevel));
  assert( pWInfo->eOnePass==ONEPASS_OFF );  /* ONEPASS defaults to OFF */
  pMaskSet = &pWInfo->sMaskSet;
  pMaskSet->n = 0;
  pMaskSet->ix[0] = -99; /* Initialize ix[0] to a value that can never be

      }
    }
  #endif
  }

  /* Analyze all of the subexpressions. */
  sqlite3WhereExprAnalyze(pTabList, &pWInfo->sWC);
  sqlite3WhereAddLimit(&pWInfo->sWC, pLimit);
  if( db->mallocFailed ) goto whereBeginError;

  /* Special case: WHERE terms that do not refer to any tables in the join
  ** (constant expressions). Evaluate each such term, and jump over all the
  ** generated code if the result is not true.
  **
  ** Do not do this if the expression contains non-deterministic functions

static void fts5SourceIdFunc(
  sqlite3_context *pCtx,          /* Function call context */
  int nArg,                       /* Number of args */
  sqlite3_value **apUnused        /* Function arguments */
){
  assert( nArg==0 );
  UNUSED_PARAM2(nArg, apUnused);
  sqlite3_result_text(pCtx, "fts5: 2022-01-25 00:03:25 a8db69411b0d1275909adeb21027784ada17af24efe3a59ae0ae2a897659ff17", -1, SQLITE_TRANSIENT);
  sqlite3_result_text(pCtx, "fts5: 2022-01-31 14:14:29 539cef5214446a7181614793e9cf323e95ba00ba0f888585b14b598dd2ff0808", -1, SQLITE_TRANSIENT);
}

/*
** Return true if zName is the extension on one of the shadow tables used
** by this module.
*/
static int fts5ShadowName(const char *zName){