Fossil

  if( c=='f' && strncmp(azArg[0], "filectrl", n)==0 ){
    static const struct {
       const char *zCtrlName;   /* Name of a test-control option */
       int ctrlCode;            /* Integer code for that option */
       const char *zUsage;      /* Usage notes */
    } aCtrl[] = {

      { "chunk_size",     SQLITE_FCNTL_CHUNK_SIZE,      "SIZE"           },
      { "data_version",   SQLITE_FCNTL_DATA_VERSION,    ""               },
      { "has_moved",      SQLITE_FCNTL_HAS_MOVED,       ""               },  
      { "lock_timeout",   SQLITE_FCNTL_LOCK_TIMEOUT,    "MILLISEC"       },
      { "persist_wal",    SQLITE_FCNTL_PERSIST_WAL,     "[BOOLEAN]"      },
   /* { "pragma",         SQLITE_FCNTL_PRAGMA,          "NAME ARG"       },*/
      { "psow",       SQLITE_FCNTL_POWERSAFE_OVERWRITE, "[BOOLEAN]"      },
      { "reserve_bytes",  SQLITE_FCNTL_RESERVE_BYTES,   "[N]"            },
      { "size_limit",     SQLITE_FCNTL_SIZE_LIMIT,      "[LIMIT]"        },
      { "tempfilename",   SQLITE_FCNTL_TEMPFILENAME,    ""               },
   /* { "win32_av_retry", SQLITE_FCNTL_WIN32_AV_RETRY,  "COUNT DELAY"    },*/


    };
    int filectrl = -1;
    int iCtrl = -1;
    sqlite3_int64 iRes = 0;  /* Integer result to display if rc2==1 */
    int isOk = 0;            /* 0: usage  1: %lld  2: no-result */
    int n2, i;
    const char *zCmd = 0;

          if( nArg!=2 && nArg!=3 ) break;
          x = nArg==3 ? booleanValue(azArg[2]) : -1;
          sqlite3_file_control(p->db, zSchema, filectrl, &x);
          iRes = x;
          isOk = 1;
          break;
        }
        case SQLITE_FCNTL_DATA_VERSION:
        case SQLITE_FCNTL_HAS_MOVED: {
          int x;
          if( nArg!=2 ) break;
          sqlite3_file_control(p->db, zSchema, filectrl, &x);
          iRes = x;
          isOk = 1;
          break;

#if SQLITE_ENABLE_LOAD_EXTENSION
  "ENABLE_LOAD_EXTENSION",
#endif
#ifdef SQLITE_ENABLE_LOCKING_STYLE
  "ENABLE_LOCKING_STYLE=" CTIMEOPT_VAL(SQLITE_ENABLE_LOCKING_STYLE),
#endif
#if SQLITE_ENABLE_MATH_FUNCTIONS
  "ENABLE_MATH_FUNCTIONS",
#endif
#if SQLITE_ENABLE_MEMORY_MANAGEMENT
  "ENABLE_MEMORY_MANAGEMENT",
#endif
#if SQLITE_ENABLE_MEMSYS3
  "ENABLE_MEMSYS3",
#endif

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.35.0"
#define SQLITE_VERSION_NUMBER 3035000
#define SQLITE_SOURCE_ID      "2020-12-30 13:20:27 45f46317ab8bd92dcd346bf00ba3a33b0cfd030b790c04e19ef33cff124d8d7f"

/*
** 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

**          Regardless of whether or not shared-cache mode is enabled by
**          default, use a private cache.
** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
**          that uses dot-files in place of posix advisory locking.
** <tr><td> file:data.db?mode=readonly <td>
**          An error. "readonly" is not a valid option for the "mode" parameter.
**          Use "ro" instead:  "file:data.db?mode=ro".
** </table>
**
** ^URI hexadecimal escape sequences (%HH) are supported within the path and
** query components of a URI. A hexadecimal escape sequence consists of a
** percent sign - "%" - followed by exactly two hexadecimal digits
** specifying an octet value. ^Before the path or query components of a
** URI filename are interpreted, they are encoded using UTF-8 and all

** an attached table is modified and then later on the original values
** are restored. However, if this function returns non-zero, then it is
** guaranteed that a call to sqlite3session_changeset() will return a
** changeset containing zero changes.
*/
SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);

/*
** CAPI3REF: Query for the amount of heap memory used by a session object.
**
** This API returns the total amount of heap memory in bytes currently
** used by the session object passed as the only argument.
*/
SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);

/*
** CAPI3REF: Create An Iterator To Traverse A Changeset
** CONSTRUCTOR: sqlite3_changeset_iter
**
** Create an iterator used to iterate through the contents of a changeset.
** If successful, *pp is set to point to the iterator handle and SQLITE_OK
** is returned. Otherwise, if an error occurs, *pp is set to zero and an

# define SELECTTRACE(K,P,S,X)
# define SELECTTRACE_ENABLED 0
#endif

/*
** Macros for "wheretrace"
*/
SQLITE_PRIVATE u32 sqlite3WhereTrace;
#if defined(SQLITE_DEBUG) \
    && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_WHERETRACE))

# define WHERETRACE(K,X)  if(sqlite3WhereTrace&(K)) sqlite3DebugPrintf X
# define WHERETRACE_ENABLED 1
#else
# define WHERETRACE(K,X)
#endif

                         ** TK_IN: ephemerial table holding RHS
                         ** TK_SELECT_COLUMN: Number of columns on the LHS
                         ** TK_SELECT: 1st register of result vector */
  ynVar iColumn;         /* TK_COLUMN: column index.  -1 for rowid.
                         ** TK_VARIABLE: variable number (always >= 1).
                         ** TK_SELECT_COLUMN: column of the result vector */
  i16 iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
  int iRightJoinTable;   /* If EP_FromJoin, the right table of the join */
  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
  union {
    Table *pTab;           /* TK_COLUMN: Table containing column. Can be NULL
                           ** for a column of an index on an expression */
    Window *pWin;          /* EP_WinFunc: Window/Filter defn for a function */
    struct {               /* TK_IN, TK_SELECT, and TK_EXISTS */
      int iAddr;             /* Subroutine entry address */

SQLITE_PRIVATE Window *sqlite3WindowAlloc(Parse*, int, int, Expr*, int , Expr*, u8);
SQLITE_PRIVATE void sqlite3WindowAttach(Parse*, Expr*, Window*);
SQLITE_PRIVATE void sqlite3WindowLink(Select *pSel, Window *pWin);
SQLITE_PRIVATE int sqlite3WindowCompare(Parse*, Window*, Window*, int);
SQLITE_PRIVATE void sqlite3WindowCodeInit(Parse*, Select*);
SQLITE_PRIVATE void sqlite3WindowCodeStep(Parse*, Select*, WhereInfo*, int, int);
SQLITE_PRIVATE int sqlite3WindowRewrite(Parse*, Select*);

SQLITE_PRIVATE void sqlite3WindowUpdate(Parse*, Window*, Window*, FuncDef*);
SQLITE_PRIVATE Window *sqlite3WindowDup(sqlite3 *db, Expr *pOwner, Window *p);
SQLITE_PRIVATE Window *sqlite3WindowListDup(sqlite3 *db, Window *p);
SQLITE_PRIVATE void sqlite3WindowFunctions(void);
SQLITE_PRIVATE void sqlite3WindowChain(Parse*, Window*, Window*);
SQLITE_PRIVATE Window *sqlite3WindowAssemble(Parse*, Window*, ExprList*, ExprList*, Token*);
#else

SQLITE_PRIVATE void sqlite3AlterRenameColumn(Parse*, SrcList*, Token*, Token*);
SQLITE_PRIVATE int sqlite3GetToken(const unsigned char *, int *);
SQLITE_PRIVATE void sqlite3NestedParse(Parse*, const char*, ...);
SQLITE_PRIVATE void sqlite3ExpirePreparedStatements(sqlite3*, int);
SQLITE_PRIVATE void sqlite3CodeRhsOfIN(Parse*, Expr*, int);
SQLITE_PRIVATE int sqlite3CodeSubselect(Parse*, Expr*);
SQLITE_PRIVATE void sqlite3SelectPrep(Parse*, Select*, NameContext*);
SQLITE_PRIVATE int sqlite3ExpandSubquery(Parse*, struct SrcList_item*);
SQLITE_PRIVATE void sqlite3SelectWrongNumTermsError(Parse *pParse, Select *p);
SQLITE_PRIVATE int sqlite3MatchEName(
  const struct ExprList_item*,
  const char*,
  const char*,
  const char*
);

  u32 nRem;                     /* Bytes of data still to copy */

  getCellInfo(pSrc);
  aOut += putVarint32(aOut, pSrc->info.nPayload);
  if( pDest->pKeyInfo==0 ) aOut += putVarint(aOut, iKey);
  nIn = pSrc->info.nLocal;
  aIn = pSrc->info.pPayload;
  if( aIn+nIn>pSrc->pPage->aDataEnd ){
    return SQLITE_CORRUPT_BKPT;
  }
  nRem = pSrc->info.nPayload;
  if( nIn==nRem && nIn<pDest->pPage->maxLocal ){
    memcpy(aOut, aIn, nIn);
    pBt->nPreformatSize = nIn + (aOut - pBt->pTmpSpace);
  }else{
    Pager *pSrcPager = pSrc->pBt->pPager;
    u8 *pPgnoOut = 0;
    Pgno ovflIn = 0;
    DbPage *pPageIn = 0;
    MemPage *pPageOut = 0;
    u32 nOut;                     /* Size of output buffer aOut[] */

    nOut = btreePayloadToLocal(pDest->pPage, pSrc->info.nPayload);
    pBt->nPreformatSize = nOut + (aOut - pBt->pTmpSpace);
    if( nOut<pSrc->info.nPayload ){
      pPgnoOut = &aOut[nOut];
      pBt->nPreformatSize += 4;
    }

    if( nRem>nIn ){
      if( aIn+nIn+4>pSrc->pPage->aDataEnd ){
        return SQLITE_CORRUPT_BKPT;
      }
      ovflIn = get4byte(&pSrc->info.pPayload[nIn]);
    }

    do {
      nRem -= nOut;
      do{
        assert( nOut>0 );

        testcase( zRawSql[0]=='$' );
        testcase( zRawSql[0]=='@' );
        testcase( zRawSql[0]=='#' );
        idx = sqlite3VdbeParameterIndex(p, zRawSql, nToken);
        assert( idx>0 );
      }
      zRawSql += nToken;
      nextIndex = MAX(idx + 1, nextIndex);
      assert( idx>0 && idx<=p->nVar );
      pVar = &p->aVar[idx-1];
      if( pVar->flags & MEM_Null ){
        sqlite3_str_append(&out, "NULL", 4);
      }else if( pVar->flags & (MEM_Int|MEM_IntReal) ){
        sqlite3_str_appendf(&out, "%lld", pVar->u.i);
      }else if( pVar->flags & MEM_Real ){

** with the OPFLAG_PREFORMAT flag set to complete the insert operation.
*/
case OP_RowCell: {
  VdbeCursor *pDest;              /* Cursor to write to */
  VdbeCursor *pSrc;               /* Cursor to read from */
  i64 iKey;                       /* Rowid value to insert with */
  assert( pOp[1].opcode==OP_Insert || pOp[1].opcode==OP_IdxInsert );
  assert( pOp[1].opcode==OP_Insert    || pOp->p3==0 );
  assert( pOp[1].opcode==OP_IdxInsert || pOp->p3>0 );
  assert( pOp[1].p5 & OPFLAG_PREFORMAT );
  pDest = p->apCsr[pOp->p1];
  pSrc = p->apCsr[pOp->p2];
  iKey = pOp->p3 ? aMem[pOp->p3].u.i : 0;
  rc = sqlite3BtreeTransferRow(pDest->uc.pCursor, pSrc->uc.pCursor, iKey);
  if( rc!=SQLITE_OK ) goto abort_due_to_error;
  break;

#if !defined(SQLITE_OMIT_WINDOWFUNC)
/*
** Walk all expressions linked into the list of Window objects passed
** as the second argument.
*/
static int walkWindowList(Walker *pWalker, Window *pList, int bOneOnly){
  Window *pWin;
  for(pWin=pList; pWin; pWin=pWin->pNextWin){
    int rc;
    rc = sqlite3WalkExprList(pWalker, pWin->pOrderBy);
    if( rc ) return WRC_Abort;
    rc = sqlite3WalkExprList(pWalker, pWin->pPartition);
    if( rc ) return WRC_Abort;
    rc = sqlite3WalkExpr(pWalker, pWin->pFilter);
    if( rc ) return WRC_Abort;

    /* The next two are purely for calls to sqlite3RenameExprUnmap()
    ** within sqlite3WindowOffsetExpr().  Because of constraints imposed
    ** by sqlite3WindowOffsetExpr(), they can never fail.  The results do
    ** not matter anyhow. */
    rc = sqlite3WalkExpr(pWalker, pWin->pStart);
    if( NEVER(rc) ) return WRC_Abort;
    rc = sqlite3WalkExpr(pWalker, pWin->pEnd);
    if( NEVER(rc) ) return WRC_Abort;
    if( bOneOnly ) break;
  }
  return WRC_Continue;
}
#endif

/*
** Walk an expression tree.  Invoke the callback once for each node

        if( sqlite3WalkSelect(pWalker, pExpr->x.pSelect) ) return WRC_Abort;
      }else{
        if( pExpr->x.pList ){
          if( sqlite3WalkExprList(pWalker, pExpr->x.pList) ) return WRC_Abort;
        }
#ifndef SQLITE_OMIT_WINDOWFUNC
        if( ExprHasProperty(pExpr, EP_WinFunc) ){
          if( walkWindowList(pWalker, pExpr->y.pWin, 1) ) return WRC_Abort;
        }
#endif
      }
    }
    break;
  }
  return WRC_Continue;

  if( sqlite3WalkExpr(pWalker, p->pLimit) ) return WRC_Abort;
#if !defined(SQLITE_OMIT_WINDOWFUNC) && !defined(SQLITE_OMIT_ALTERTABLE)
  {
    Parse *pParse = pWalker->pParse;
    if( pParse && IN_RENAME_OBJECT ){
      /* The following may return WRC_Abort if there are unresolvable
      ** symbols (e.g. a table that does not exist) in a window definition. */
      int rc = walkWindowList(pWalker, p->pWinDefn, 0);
      return rc;
    }
  }
#endif
  return WRC_Continue;
}

    /* If the response to a rowid conflict is REPLACE but the response
    ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
    ** to defer the running of the rowid conflict checking until after
    ** the UNIQUE constraints have run.
    */
    if( onError==OE_Replace      /* IPK rule is REPLACE */
     && onError!=overrideError   /* Rules for other constraints are different */
     && pTab->pIndex             /* There exist other constraints */
    ){
      ipkTop = sqlite3VdbeAddOp0(v, OP_Goto)+1;
      VdbeComment((v, "defer IPK REPLACE until last"));
    }

    if( isUpdate ){

      for(i=0; i<pSrcIdx->nColumn; i++){
        const char *zColl = pSrcIdx->azColl[i];
        if( sqlite3_stricmp(sqlite3StrBINARY, zColl) ) break;
      }
      if( i==pSrcIdx->nColumn ){
        idxInsFlags = OPFLAG_USESEEKRESULT|OPFLAG_PREFORMAT;
        sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
        sqlite3VdbeAddOp2(v, OP_RowCell, iDest, iSrc);
      }
    }else if( !HasRowid(pSrc) && pDestIdx->idxType==SQLITE_IDXTYPE_PRIMARYKEY ){
      idxInsFlags |= OPFLAG_NCHANGE;
    }
    if( idxInsFlags!=(OPFLAG_USESEEKRESULT|OPFLAG_PREFORMAT) ){
      sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
    }

  pE2 = sqlite3CreateColumnExpr(db, pSrc, iRight, iColRight);

  pEq = sqlite3PExpr(pParse, TK_EQ, pE1, pE2);
  if( pEq && isOuterJoin ){
    ExprSetProperty(pEq, EP_FromJoin);
    assert( !ExprHasProperty(pEq, EP_TokenOnly|EP_Reduced) );
    ExprSetVVAProperty(pEq, EP_NoReduce);
    pEq->iRightJoinTable = pE2->iTable;
  }
  *ppWhere = sqlite3ExprAnd(pParse, *ppWhere, pEq);
}

/*
** Set the EP_FromJoin property on all terms of the given expression.
** And set the Expr.iRightJoinTable to iTable for every term in the

** the output, which is incorrect.
*/
SQLITE_PRIVATE void sqlite3SetJoinExpr(Expr *p, int iTable){
  while( p ){
    ExprSetProperty(p, EP_FromJoin);
    assert( !ExprHasProperty(p, EP_TokenOnly|EP_Reduced) );
    ExprSetVVAProperty(p, EP_NoReduce);
    p->iRightJoinTable = iTable;
    if( p->op==TK_FUNCTION && p->x.pList ){
      int i;
      for(i=0; i<p->x.pList->nExpr; i++){
        sqlite3SetJoinExpr(p->x.pList->a[i].pExpr, iTable);
      }
    }
    sqlite3SetJoinExpr(p->pLeft, iTable);

  w.xSelectCallback = sqlite3SelectWalkNoop;
  w.u.pSrcItem = pSrcItem;
  pSrcItem->colUsed = 0;
  sqlite3WalkSelect(&w, pSelect);
}
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */

#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
/*
** Assign new cursor numbers to each of the items in pSrc. For each
** new cursor number assigned, set an entry in the aCsrMap[] array
** to map the old cursor number to the new:
**
**     aCsrMap[iOld] = iNew;
**
** The array is guaranteed by the caller to be large enough for all
** existing cursor numbers in pSrc.
**
** If pSrc contains any sub-selects, call this routine recursively
** on the FROM clause of each such sub-select, with iExcept set to -1.
*/
static void srclistRenumberCursors(
  Parse *pParse,                  /* Parse context */
  int *aCsrMap,                   /* Array to store cursor mappings in */
  SrcList *pSrc,                  /* FROM clause to renumber */
  int iExcept                     /* FROM clause item to skip */
){
  int i;
  struct SrcList_item *pItem;
  for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){
    if( i!=iExcept ){
      Select *p;
      pItem->iCursor = aCsrMap[pItem->iCursor] = pParse->nTab++;
      for(p=pItem->pSelect; p; p=p->pPrior){
        srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1);
      }
    }
  }
}

/*
** Expression walker callback used by renumberCursors() to update
** Expr objects to match newly assigned cursor numbers.
*/
static int renumberCursorsCb(Walker *pWalker, Expr *pExpr){
  int *aCsrMap = pWalker->u.aiCol;
  if( pExpr->op==TK_COLUMN && aCsrMap[pExpr->iTable] ){
    pExpr->iTable = aCsrMap[pExpr->iTable];
  }
  if( ExprHasProperty(pExpr, EP_FromJoin) && aCsrMap[pExpr->iRightJoinTable] ){
    pExpr->iRightJoinTable = aCsrMap[pExpr->iRightJoinTable];
  }
  return WRC_Continue;
}

/*
** Assign a new cursor number to each cursor in the FROM clause (Select.pSrc)
** of the SELECT statement passed as the second argument, and to each
** cursor in the FROM clause of any FROM clause sub-selects, recursively.
** Except, do not assign a new cursor number to the iExcept'th element in
** the FROM clause of (*p). Update all expressions and other references
** to refer to the new cursor numbers.
**
** Argument aCsrMap is an array that may be used for temporary working
** space. Two guarantees are made by the caller:
**
**   * the array is larger than the largest cursor number used within the
**     select statement passed as an argument, and
**
**   * the array entries for all cursor numbers that do *not* appear in
**     FROM clauses of the select statement as described above are
**     initialized to zero.
*/
static void renumberCursors(
  Parse *pParse,                  /* Parse context */
  Select *p,                      /* Select to renumber cursors within */
  int iExcept,                    /* FROM clause item to skip */
  int *aCsrMap                    /* Working space */
){
  Walker w;
  srclistRenumberCursors(pParse, aCsrMap, p->pSrc, iExcept);
  memset(&w, 0, sizeof(w));
  w.u.aiCol = aCsrMap;
  w.xExprCallback = renumberCursorsCb;
  w.xSelectCallback = sqlite3SelectWalkNoop;
  sqlite3WalkSelect(&w, p);
}
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */

#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
/*
** This routine attempts to flatten subqueries as a performance optimization.
** This routine returns 1 if it makes changes and 0 if no flattening occurs.
**
** To understand the concept of flattening, consider the following
** query:

**  (17)  If the subquery is a compound select, then
**        (17a) all compound operators must be a UNION ALL, and
**        (17b) no terms within the subquery compound may be aggregate
**              or DISTINCT, and
**        (17c) every term within the subquery compound must have a FROM clause
**        (17d) the outer query may not be
**              (17d1) aggregate, or
**              (17d2) DISTINCT

**        (17e) the subquery may not contain window functions, and
**        (17f) the subquery must not be the RHS of a LEFT JOIN.
**
**        The parent and sub-query may contain WHERE clauses. Subject to
**        rules (11), (13) and (14), they may also contain ORDER BY,
**        LIMIT and OFFSET clauses.  The subquery cannot use any compound
**        operator other than UNION ALL because all the other compound
**        operators have an implied DISTINCT which is disallowed by
**        restriction (4).
**
**        Also, each component of the sub-query must return the same number
**        of result columns. This is actually a requirement for any compound
**        SELECT statement, but all the code here does is make sure that no
**        such (illegal) sub-query is flattened. The caller will detect the
**        syntax error and return a detailed message.
**
**  (18)  If the sub-query is a compound select, then all terms of the
**        ORDER BY clause of the parent must be copies of a term returned
**        by the parent query.
**
**  (19)  If the subquery uses LIMIT then the outer query may not
**        have a WHERE clause.
**
**  (20)  If the sub-query is a compound select, then it must not use
**        an ORDER BY clause.  Ticket #3773.  We could relax this constraint
**        somewhat by saying that the terms of the ORDER BY clause must
**        appear as unmodified result columns in the outer query.  But we
**        have other optimizations in mind to deal with that case.
**
**  (21)  If the subquery uses LIMIT then the outer query may not be
**        DISTINCT.  (See ticket [752e1646fc]).
**
**  (22)  The subquery may not be a recursive CTE.
**

**  (23)  If the outer query is a recursive CTE, then the sub-query may not be
**        a compound query.  This restriction is because transforming the
**        parent to a compound query confuses the code that handles
**        recursive queries in multiSelect().
**
**  (**)  We no longer attempt to flatten aggregate subqueries.  Was:
**        The subquery may not be an aggregate that uses the built-in min() or
**        or max() functions.  (Without this restriction, a query like:
**        "SELECT x FROM (SELECT max(y), x FROM t1)" would not necessarily

  int iNewParent = -1;/* Replacement table for iParent */
  int isLeftJoin = 0; /* True if pSub is the right side of a LEFT JOIN */
  int i;              /* Loop counter */
  Expr *pWhere;                    /* The WHERE clause */
  struct SrcList_item *pSubitem;   /* The subquery */
  sqlite3 *db = pParse->db;
  Walker w;                        /* Walker to persist agginfo data */
  int *aCsrMap = 0;

  /* Check to see if flattening is permitted.  Return 0 if not.
  */
  assert( p!=0 );
  assert( p->pPrior==0 );
  if( OptimizationDisabled(db, SQLITE_QueryFlattener) ) return 0;
  pSrc = p->pSrc;

  ** that make up the compound SELECT are allowed to be aggregate or distinct
  ** queries.
  */
  if( pSub->pPrior ){
    if( pSub->pOrderBy ){
      return 0;  /* Restriction (20) */
    }
    if( isAgg || (p->selFlags & SF_Distinct)!=0 || isLeftJoin>0 ){
      return 0; /* (17d1), (17d2), or (17f) */
    }
    for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Distinct );
      testcase( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))==SF_Aggregate );
      assert( pSub->pSrc!=0 );
      assert( (pSub->selFlags & SF_Recursive)==0 );
      assert( pSub->pEList->nExpr==pSub1->pEList->nExpr );
      if( (pSub1->selFlags & (SF_Distinct|SF_Aggregate))!=0    /* (17b) */
       || (pSub1->pPrior && pSub1->op!=TK_ALL)                 /* (17a) */
       || pSub1->pSrc->nSrc<1                                  /* (17c) */
#ifndef SQLITE_OMIT_WINDOWFUNC
       || pSub1->pWin                                          /* (17e) */
#endif
      ){
        return 0;
      }
      testcase( pSub1->pSrc->nSrc>1 );
    }

    /* Restriction (18). */
    if( p->pOrderBy ){
      int ii;
      for(ii=0; ii<p->pOrderBy->nExpr; ii++){
        if( p->pOrderBy->a[ii].u.x.iOrderByCol==0 ) return 0;
      }
    }


    /* Restriction (23) */





    if( (p->selFlags & SF_Recursive) ) return 0;

    if( pSrc->nSrc>1 ){
      aCsrMap = sqlite3DbMallocZero(db, pParse->nTab*sizeof(int));
    }
  }

  /***** If we reach this point, flattening is permitted. *****/
  SELECTTRACE(1,pParse,p,("flatten %u.%p from term %d\n",
                   pSub->selId, pSub, iFrom));

  /* Authorize the subquery */
  pParse->zAuthContext = pSubitem->zName;
  TESTONLY(i =) sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0);
  testcase( i==SQLITE_DENY );
  pParse->zAuthContext = zSavedAuthContext;

  /* Delete the transient structures associated with thesubquery */
  pSub1 = pSubitem->pSelect;
  sqlite3DbFree(db, pSubitem->zDatabase);
  sqlite3DbFree(db, pSubitem->zName);
  sqlite3DbFree(db, pSubitem->zAlias);
  pSubitem->zDatabase = 0;
  pSubitem->zName = 0;
  pSubitem->zAlias = 0;
  pSubitem->pSelect = 0;
  assert( pSubitem->pOn==0 );

  /* If the sub-query is a compound SELECT statement, then (by restrictions
  ** 17 and 18 above) it must be a UNION ALL and the parent query must
  ** be of the form:
  **
  **     SELECT <expr-list> FROM (<sub-query>) <where-clause>
  **

  ** We call this the "compound-subquery flattening".
  */
  for(pSub=pSub->pPrior; pSub; pSub=pSub->pPrior){
    Select *pNew;
    ExprList *pOrderBy = p->pOrderBy;
    Expr *pLimit = p->pLimit;
    Select *pPrior = p->pPrior;
    Table *pItemTab = pSubitem->pTab;
    pSubitem->pTab = 0;
    p->pOrderBy = 0;

    p->pPrior = 0;
    p->pLimit = 0;
    pNew = sqlite3SelectDup(db, p, 0);
    p->pLimit = pLimit;
    p->pOrderBy = pOrderBy;

    p->op = TK_ALL;
    pSubitem->pTab = pItemTab;
    if( pNew==0 ){
      p->pPrior = pPrior;
    }else{
      if( aCsrMap && db->mallocFailed==0 ){
        renumberCursors(pParse, pNew, iFrom, aCsrMap);
      }
      pNew->pPrior = pPrior;
      if( pPrior ) pPrior->pNext = pNew;
      pNew->pNext = p;
      p->pPrior = pNew;
      SELECTTRACE(2,pParse,p,("compound-subquery flattener"
                              " creates %u as peer\n",pNew->selId));
    }






    assert( pSubitem->pSelect==0 );
  }




  sqlite3DbFree(db, aCsrMap);


  if( db->mallocFailed ){

    pSubitem->pSelect = pSub1;
    return 1;
  }

  /* Defer deleting the Table object associated with the
  ** subquery until code generation is
  ** complete, since there may still exist Expr.pTab entries that
  ** refer to the subquery even after flattening.  Ticket #3346.
  **
  ** pSubitem->pTab is always non-NULL by test restrictions and tests above.

  ** the FROM clause of the outer query.  Before doing this, remember
  ** the cursor number for the original outer query FROM element in
  ** iParent.  The iParent cursor will never be used.  Subsequent code
  ** will scan expressions looking for iParent references and replace
  ** those references with expressions that resolve to the subquery FROM
  ** elements we are now copying in.
  */
  pSub = pSub1;
  for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){
    int nSubSrc;
    u8 jointype = 0;
    assert( pSub!=0 );
    pSubSrc = pSub->pSrc;     /* FROM clause of subquery */
    nSubSrc = pSubSrc->nSrc;  /* Number of terms in subquery FROM clause */
    pSrc = pParent->pSrc;     /* FROM clause of the outer query */


    if( pParent==p ){
      jointype = pSubitem->fg.jointype;     /* First time through the loop */





    }

    /* The subquery uses a single slot of the FROM clause of the outer
    ** query.  If the subquery has more than one element in its FROM clause,
    ** then expand the outer query to make space for it to hold all elements
    ** of the subquery.
    **

** sub-expression matches the criteria for being moved to the WHERE
** clause. If so, add it to the WHERE clause and replace the sub-expression
** within the HAVING expression with a constant "1".
*/
static int havingToWhereExprCb(Walker *pWalker, Expr *pExpr){
  if( pExpr->op!=TK_AND ){
    Select *pS = pWalker->u.pSelect;
    if( sqlite3ExprIsConstantOrGroupBy(pWalker->pParse, pExpr, pS->pGroupBy)
     && ExprAlwaysFalse(pExpr)==0
    ){
      sqlite3 *db = pWalker->pParse->db;
      Expr *pNew = sqlite3Expr(db, TK_INTEGER, "1");
      if( pNew ){
        Expr *pWhere = pS->pWhere;
        SWAP(Expr, *pNew, *pExpr);
        pNew = sqlite3ExprAnd(pWalker->pParse, pWhere, pNew);
        pS->pWhere = pNew;

  */
select_end:
  sqlite3ExprListDelete(db, pMinMaxOrderBy);
#ifdef SQLITE_DEBUG
  if( pAggInfo && !db->mallocFailed ){
    for(i=0; i<pAggInfo->nColumn; i++){
      Expr *pExpr = pAggInfo->aCol[i].pCExpr;
      assert( pExpr!=0 );

      assert( pExpr->pAggInfo==pAggInfo );
      assert( pExpr->iAgg==i );
    }
    for(i=0; i<pAggInfo->nFunc; i++){
      Expr *pExpr = pAggInfo->aFunc[i].pFExpr;
      assert( pExpr!=0 );

      assert( pExpr->pAggInfo==pAggInfo );
      assert( pExpr->iAgg==i );
    }
  }
#endif

#if SELECTTRACE_ENABLED

      pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_BTM_LIMIT;
      pNew->u.btree.nBtm = whereRangeVectorLen(
          pParse, pSrc->iCursor, pProbe, saved_nEq, pTerm
      );
      pBtm = pTerm;
      pTop = 0;
      if( pTerm->wtFlags & TERM_LIKEOPT ){
        /* Range constraints that come from the LIKE optimization are
        ** always used in pairs. */
        pTop = &pTerm[1];
        assert( (pTop-(pTerm->pWC->a))<pTerm->pWC->nTerm );
        assert( pTop->wtFlags & TERM_LIKEOPT );
        assert( pTop->eOperator==WO_LT );
        if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */
        pNew->aLTerm[pNew->nLTerm++] = pTop;

  char *zDb;                      /* Name of database session is attached to */
  int bEnable;                    /* True if currently recording */
  int bIndirect;                  /* True if all changes are indirect */
  int bAutoAttach;                /* True to auto-attach tables */
  int rc;                         /* Non-zero if an error has occurred */
  void *pFilterCtx;               /* First argument to pass to xTableFilter */
  int (*xTableFilter)(void *pCtx, const char *zTab);
  i64 nMalloc;                    /* Number of bytes of data allocated */
  sqlite3_value *pZeroBlob;       /* Value containing X'' */
  sqlite3_session *pNext;         /* Next session object on same db. */
  SessionTable *pTable;           /* List of attached tables */
  SessionHook hook;               /* APIs to grab new and old data with */
};

/*

    if( aBuf ) aBuf[0] = '\0';
  }

  if( pnWrite ) *pnWrite += nByte;
  return SQLITE_OK;
}

/*
** Allocate and return a pointer to a buffer nByte bytes in size. If
** pSession is not NULL, increase the sqlite3_session.nMalloc variable
** by the number of bytes allocated.
*/
static void *sessionMalloc64(sqlite3_session *pSession, i64 nByte){
  void *pRet = sqlite3_malloc64(nByte);
  if( pSession ) pSession->nMalloc += sqlite3_msize(pRet);
  return pRet;
}

/*
** Free buffer pFree, which must have been allocated by an earlier
** call to sessionMalloc64(). If pSession is not NULL, decrease the
** sqlite3_session.nMalloc counter by the number of bytes freed.
*/
static void sessionFree(sqlite3_session *pSession, void *pFree){
  if( pSession ) pSession->nMalloc -= sqlite3_msize(pFree);
  sqlite3_free(pFree);
}

/*
** This macro is used to calculate hash key values for data structures. In
** order to use this macro, the entire data structure must be represented
** as a series of unsigned integers. In order to calculate a hash-key value
** for a data structure represented as three such integers, the macro may
** then be used as follows:

** SQLITE_OK.
**
** It is possible that a non-fatal OOM error occurs in this function. In
** that case the hash-table does not grow, but SQLITE_OK is returned anyway.
** Growing the hash table in this case is a performance optimization only,
** it is not required for correct operation.
*/
static int sessionGrowHash(
  sqlite3_session *pSession,      /* For memory accounting. May be NULL */
  int bPatchset,
  SessionTable *pTab
){
  if( pTab->nChange==0 || pTab->nEntry>=(pTab->nChange/2) ){
    int i;
    SessionChange **apNew;
    sqlite3_int64 nNew = 2*(sqlite3_int64)(pTab->nChange ? pTab->nChange : 128);

    apNew = (SessionChange**)sessionMalloc64(
        pSession, sizeof(SessionChange*) * nNew
    );
    if( apNew==0 ){
      if( pTab->nChange==0 ){
        return SQLITE_ERROR;
      }
      return SQLITE_OK;
    }
    memset(apNew, 0, sizeof(SessionChange *) * nNew);

    for(i=0; i<pTab->nChange; i++){
      SessionChange *p;
      SessionChange *pNext;
      for(p=pTab->apChange[i]; p; p=pNext){
        int bPkOnly = (p->op==SQLITE_DELETE && bPatchset);
        int iHash = sessionChangeHash(pTab, bPkOnly, p->aRecord, nNew);
        pNext = p->pNext;
        p->pNext = apNew[iHash];
        apNew[iHash] = p;
      }
    }

    sessionFree(pSession, pTab->apChange);
    pTab->nChange = nNew;
    pTab->apChange = apNew;
  }

  return SQLITE_OK;
}

**     *pazCol = {"w", "x", "y", "z"}
**     *pabPK  = {1, 0, 0, 1}
**
** All returned buffers are part of the same single allocation, which must
** be freed using sqlite3_free() by the caller
*/
static int sessionTableInfo(
  sqlite3_session *pSession,      /* For memory accounting. May be NULL */
  sqlite3 *db,                    /* Database connection */
  const char *zDb,                /* Name of attached database (e.g. "main") */
  const char *zThis,              /* Table name */
  int *pnCol,                     /* OUT: number of columns */
  const char **pzTab,             /* OUT: Copy of zThis */
  const char ***pazCol,           /* OUT: Array of column names for table */
  u8 **pabPK                      /* OUT: Array of booleans - true for PK col */

    nByte += sqlite3_column_bytes(pStmt, 1);
    nDbCol++;
  }
  rc = sqlite3_reset(pStmt);

  if( rc==SQLITE_OK ){
    nByte += nDbCol * (sizeof(const char *) + sizeof(u8) + 1);
    pAlloc = sessionMalloc64(pSession, nByte);
    if( pAlloc==0 ){
      rc = SQLITE_NOMEM;
    }
  }
  if( rc==SQLITE_OK ){
    azCol = (char **)pAlloc;
    pAlloc = (u8 *)&azCol[nDbCol];

    *pabPK = abPK;
    *pnCol = nDbCol;
  }else{
    *pazCol = 0;
    *pabPK = 0;
    *pnCol = 0;
    if( pzTab ) *pzTab = 0;
    sessionFree(pSession, azCol);
  }
  sqlite3_finalize(pStmt);
  return rc;
}

/*
** This function is only called from within a pre-update handler for a

** indicate that updates on this table should be ignored. SessionTable.abPK
** is set to NULL in this case.
*/
static int sessionInitTable(sqlite3_session *pSession, SessionTable *pTab){
  if( pTab->nCol==0 ){
    u8 *abPK;
    assert( pTab->azCol==0 || pTab->abPK==0 );
    pSession->rc = sessionTableInfo(pSession, pSession->db, pSession->zDb,
        pTab->zName, &pTab->nCol, 0, &pTab->azCol, &abPK
    );
    if( pSession->rc==SQLITE_OK ){
      int i;
      for(i=0; i<pTab->nCol; i++){
        if( abPK[i] ){
          pTab->abPK = abPK;

  ** number of columns in the table.  */
  if( pTab->nCol!=pSession->hook.xCount(pSession->hook.pCtx) ){
    pSession->rc = SQLITE_SCHEMA;
    return;
  }

  /* Grow the hash table if required */
  if( sessionGrowHash(pSession, 0, pTab) ){
    pSession->rc = SQLITE_NOMEM;
    return;
  }

  if( pTab->bStat1 ){
    stat1.hook = pSession->hook;
    stat1.pSession = pSession;

        /* This may fail if SQLite value p contains a utf-16 string that must
        ** be converted to utf-8 and an OOM error occurs while doing so. */
        rc = sessionSerializeValue(0, p, &nByte);
        if( rc!=SQLITE_OK ) goto error_out;
      }

      /* Allocate the change object */
      pChange = (SessionChange *)sessionMalloc64(pSession, nByte);
      if( !pChange ){
        rc = SQLITE_NOMEM;
        goto error_out;
      }else{
        memset(pChange, 0, sizeof(SessionChange));
        pChange->aRecord = (u8 *)&pChange[1];
      }

    /* Check the table schemas match */
    if( rc==SQLITE_OK ){
      int bHasPk = 0;
      int bMismatch = 0;
      int nCol;                   /* Columns in zFrom.zTbl */
      u8 *abPK;
      const char **azCol = 0;
      rc = sessionTableInfo(0, db, zFrom, zTbl, &nCol, 0, &azCol, &abPK);
      if( rc==SQLITE_OK ){
        if( pTo->nCol!=nCol ){
          bMismatch = 1;
        }else{
          int i;
          for(i=0; i<nCol; i++){
            if( pTo->abPK[i]!=abPK[i] ) bMismatch = 1;

  return SQLITE_OK;
}

/*
** Free the list of table objects passed as the first argument. The contents
** of the changed-rows hash tables are also deleted.
*/
static void sessionDeleteTable(sqlite3_session *pSession, SessionTable *pList){
  SessionTable *pNext;
  SessionTable *pTab;

  for(pTab=pList; pTab; pTab=pNext){
    int i;
    pNext = pTab->pNext;
    for(i=0; i<pTab->nChange; i++){
      SessionChange *p;
      SessionChange *pNextChange;
      for(p=pTab->apChange[i]; p; p=pNextChange){
        pNextChange = p->pNext;
        sessionFree(pSession, p);
      }
    }
    sessionFree(pSession, (char*)pTab->azCol);  /* cast works around VC++ bug */
    sessionFree(pSession, pTab->apChange);
    sessionFree(pSession, pTab);
  }
}

/*
** Delete a session object previously allocated using sqlite3session_create().
*/
SQLITE_API void sqlite3session_delete(sqlite3_session *pSession){

    }
  }
  sqlite3_mutex_leave(sqlite3_db_mutex(db));
  sqlite3ValueFree(pSession->pZeroBlob);

  /* Delete all attached table objects. And the contents of their
  ** associated hash-tables. */
  sessionDeleteTable(pSession, pSession->pTable);

  /* Assert that all allocations have been freed and then free the
  ** session object itself. */
  assert( pSession->nMalloc==0 );
  sqlite3_free(pSession);
}

/*
** Set a table filter on a Session Object.
*/
SQLITE_API void sqlite3session_table_filter(

    nName = sqlite3Strlen30(zName);
    for(pTab=pSession->pTable; pTab; pTab=pTab->pNext){
      if( 0==sqlite3_strnicmp(pTab->zName, zName, nName+1) ) break;
    }

    if( !pTab ){
      /* Allocate new SessionTable object. */
      int nByte = sizeof(SessionTable) + nName + 1;
      pTab = (SessionTable*)sessionMalloc64(pSession, nByte);
      if( !pTab ){
        rc = SQLITE_NOMEM;
      }else{
        /* Populate the new SessionTable object and link it into the list.
        ** The new object must be linked onto the end of the list, not
        ** simply added to the start of it in order to ensure that tables
        ** appear in the correct order when a changeset or patchset is

      const char **azCol = 0;     /* Table columns */
      int i;                      /* Used to iterate through hash buckets */
      sqlite3_stmt *pSel = 0;     /* SELECT statement to query table pTab */
      int nRewind = buf.nBuf;     /* Initial size of write buffer */
      int nNoop;                  /* Size of buffer after writing tbl header */

      /* Check the table schema is still Ok. */
      rc = sessionTableInfo(0, db, pSession->zDb, zName, &nCol, 0,&azCol,&abPK);
      if( !rc && (pTab->nCol!=nCol || memcmp(abPK, pTab->abPK, nCol)) ){
        rc = SQLITE_SCHEMA;
      }

      /* Write a table header */
      sessionAppendTableHdr(&buf, bPatchset, pTab, &rc);

  for(pTab=pSession->pTable; pTab && ret==0; pTab=pTab->pNext){
    ret = (pTab->nEntry>0);
  }
  sqlite3_mutex_leave(sqlite3_db_mutex(pSession->db));

  return (ret==0);
}

/*
** Return the amount of heap memory in use.
*/
SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession){
  return pSession->nMalloc;
}

/*
** Do the work for either sqlite3changeset_start() or start_strm().
*/
static int sessionChangesetStart(
  sqlite3_changeset_iter **pp,    /* OUT: Changeset iterator handle */
  int (*xInput)(void *pIn, void *pData, int *pnData),

        nTab = (int)strlen(zTab);
        sApply.azCol = (const char **)zTab;
      }else{
        int nMinCol = 0;
        int i;

        sqlite3changeset_pk(pIter, &abPK, 0);
        rc = sessionTableInfo(0,
            db, "main", zNew, &sApply.nCol, &zTab, &sApply.azCol, &sApply.abPK
        );
        if( rc!=SQLITE_OK ) break;
        for(i=0; i<sApply.nCol; i++){
          if( sApply.abPK[i] ) nMinCol = i+1;
        }

        *ppTab = pTab;
      }else if( pTab->nCol!=nCol || memcmp(pTab->abPK, abPK, nCol) ){
        rc = SQLITE_SCHEMA;
        break;
      }
    }

    if( sessionGrowHash(0, pIter->bPatchset, pTab) ){
      rc = SQLITE_NOMEM;
      break;
    }
    iHash = sessionChangeHash(
        pTab, (pIter->bPatchset && op==SQLITE_DELETE), aRec, pTab->nChange
    );

}

/*
** Delete a changegroup object.
*/
SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup *pGrp){
  if( pGrp ){
    sessionDeleteTable(0, pGrp->pList);
    sqlite3_free(pGrp);
  }
}

/*
** Combine two changesets together.
*/

}

/*
** Destroy a rebaser object
*/
SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p){
  if( p ){
    sessionDeleteTable(0, p->grp.pList);
    sqlite3_free(p);
  }
}

/*
** Global configuration
*/

        fts5SegIterLoadTerm(p, pIter, nKeep);
        fts5SegIterLoadNPos(p, pIter);
        if( pbNewTerm ) *pbNewTerm = 1;
      }
    }else{
      /* The following could be done by calling fts5SegIterLoadNPos(). But
      ** this block is particularly performance critical, so equivalent
      ** code is inlined.  */




      int nSz;
      assert( p->rc==SQLITE_OK );
      assert_nc( pIter->iLeafOffset<=pIter->pLeaf->nn );
      fts5FastGetVarint32(pIter->pLeaf->p, pIter->iLeafOffset, nSz);
      pIter->bDel = (nSz & 0x0001);
      pIter->nPos = nSz>>1;
      assert_nc( pIter->nPos>=0 );
    }
  }
}

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: 2020-12-30 13:20:27 45f46317ab8bd92dcd346bf00ba3a33b0cfd030b790c04e19ef33cff124d8d7f", -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){

#endif
  return rc;
}
#endif /* SQLITE_CORE */
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_STMTVTAB) */

/************** End of stmt.c ************************************************/
#if __LINE__!=232615
#undef SQLITE_SOURCE_ID
#define SQLITE_SOURCE_ID      "2020-12-30 13:20:27 45f46317ab8bd92dcd346bf00ba3a33b0cfd030b790c04e19ef33cff124dalt2"
#endif
/* Return the source-id for this library */
SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
/************************** End of sqlite3.c ******************************/

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.35.0"
#define SQLITE_VERSION_NUMBER 3035000
#define SQLITE_SOURCE_ID      "2020-12-30 13:20:27 45f46317ab8bd92dcd346bf00ba3a33b0cfd030b790c04e19ef33cff124d8d7f"

/*
** 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

**          Regardless of whether or not shared-cache mode is enabled by
**          default, use a private cache.
** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
**          that uses dot-files in place of posix advisory locking.
** <tr><td> file:data.db?mode=readonly <td>
**          An error. "readonly" is not a valid option for the "mode" parameter.
**          Use "ro" instead:  "file:data.db?mode=ro".
** </table>
**
** ^URI hexadecimal escape sequences (%HH) are supported within the path and
** query components of a URI. A hexadecimal escape sequence consists of a
** percent sign - "%" - followed by exactly two hexadecimal digits
** specifying an octet value. ^Before the path or query components of a
** URI filename are interpreted, they are encoded using UTF-8 and all

** an attached table is modified and then later on the original values
** are restored. However, if this function returns non-zero, then it is
** guaranteed that a call to sqlite3session_changeset() will return a
** changeset containing zero changes.
*/
SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);

/*
** CAPI3REF: Query for the amount of heap memory used by a session object.
**
** This API returns the total amount of heap memory in bytes currently
** used by the session object passed as the only argument.
*/
SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);

/*
** CAPI3REF: Create An Iterator To Traverse A Changeset
** CONSTRUCTOR: sqlite3_changeset_iter
**
** Create an iterator used to iterate through the contents of a changeset.
** If successful, *pp is set to point to the iterator handle and SQLITE_OK
** is returned. Otherwise, if an error occurs, *pp is set to zero and an