System.Data.SQLite

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.8.12"
#define SQLITE_VERSION_NUMBER 3008012
#define SQLITE_SOURCE_ID      "2015-09-30 14:30:19 e796c0efb6cf17444b53af75046daf7d8fa82f78"

/*
** 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

** strategy. A cost of N indicates that the cost of the strategy is similar
** to a linear scan of an SQLite table with N rows. A cost of log(N) 
** indicates that the expense of the operation is similar to that of a
** binary search on a unique indexed field of an SQLite table with N rows.
**
** ^The estimatedRows value is an estimate of the number of rows that
** will be returned by the strategy.
**
** The xBestIndex method may optionally populate the idxFlags field with a 
** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
** assumes that the strategy may visit at most one row. 
**
** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
** SQLite also assumes that if a call to the xUpdate() method is made as
** part of the same statement to delete or update a virtual table row and the
** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
** any database changes. In other words, if the xUpdate() returns
** SQLITE_CONSTRAINT, the database contents must be exactly as they were
** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
** the xUpdate method are automatically rolled back by SQLite.
**
** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
** structure for SQLite version 3.8.2. If a virtual table extension is
** used with an SQLite version earlier than 3.8.2, the results of attempting 
** to read or write the estimatedRows field are undefined (but are likely 
** to included crashing the application). The estimatedRows field should
** therefore only be used if [sqlite3_libversion_number()] returns a
** value greater than or equal to 3008002. Similarly, the idxFlags field
** was added for version 3.8.12. It may therefore only be used if
** sqlite3_libversion_number() returns a value greater than or equal to
** 3008012.
*/
struct sqlite3_index_info {
  /* Inputs */
  int nConstraint;           /* Number of entries in aConstraint */
  struct sqlite3_index_constraint {
     int iColumn;              /* Column on left-hand side of constraint */
     unsigned char op;         /* Constraint operator */

  int idxNum;                /* Number used to identify the index */
  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
  int orderByConsumed;       /* True if output is already ordered */
  double estimatedCost;           /* Estimated cost of using this index */
  /* Fields below are only available in SQLite 3.8.2 and later */
  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
  /* Fields below are only available in SQLite 3.8.12 and later */
  int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
};

/*
** CAPI3REF: Virtual Table Scan Flags
*/
#define SQLITE_INDEX_SCAN_UNIQUE      1     /* Scan visits at most 1 row */

/*
** CAPI3REF: Virtual Table Constraint Operator Codes
**
** These macros defined 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
** a query that uses a [virtual table].

/* Return true if index X is a PRIMARY KEY index */
#define IsPrimaryKeyIndex(X)  ((X)->idxType==SQLITE_IDXTYPE_PRIMARYKEY)

/* Return true if index X is a UNIQUE index */
#define IsUniqueIndex(X)      ((X)->onError!=OE_None)

/* The Index.aiColumn[] values are normally positive integer.  But
** there are some negative values that have special meaning:
*/
#define XN_ROWID     (-1)     /* Indexed column is the rowid */
#define XN_EXPR      (-2)     /* Indexed column is an expression */

/*
** Each sample stored in the sqlite_stat3 table is represented in memory 
** using a structure of this type.  See documentation at the top of the
** analyze.c source file for additional information.
*/
struct IndexSample {
  void *p;          /* Pointer to sampled record */

#ifndef SQLITE_MUTEX_OMIT
SQLITE_PRIVATE   sqlite3_mutex_methods const *sqlite3DefaultMutex(void);
SQLITE_PRIVATE   sqlite3_mutex_methods const *sqlite3NoopMutex(void);
SQLITE_PRIVATE   sqlite3_mutex *sqlite3MutexAlloc(int);
SQLITE_PRIVATE   int sqlite3MutexInit(void);
SQLITE_PRIVATE   int sqlite3MutexEnd(void);
#endif






#if !defined(SQLITE_MUTEX_OMIT) && !defined(SQLITE_MUTEX_NOOP)
SQLITE_PRIVATE   void sqlite3MemoryBarrier(void);
#else
# define sqlite3MemoryBarrier()
#endif

SQLITE_PRIVATE sqlite3_int64 sqlite3StatusValue(int);

                                        Select*,u8);
SQLITE_PRIVATE   TriggerStep *sqlite3TriggerUpdateStep(sqlite3*,Token*,ExprList*, Expr*, u8);
SQLITE_PRIVATE   TriggerStep *sqlite3TriggerDeleteStep(sqlite3*,Token*, Expr*);
SQLITE_PRIVATE   void sqlite3DeleteTrigger(sqlite3*, Trigger*);
SQLITE_PRIVATE   void sqlite3UnlinkAndDeleteTrigger(sqlite3*,int,const char*);
SQLITE_PRIVATE   u32 sqlite3TriggerColmask(Parse*,Trigger*,ExprList*,int,int,Table*,int);
# define sqlite3ParseToplevel(p) ((p)->pToplevel ? (p)->pToplevel : (p))
# define sqlite3IsToplevel(p) ((p)->pToplevel==0)
#else
# define sqlite3TriggersExist(B,C,D,E,F) 0
# define sqlite3DeleteTrigger(A,B)
# define sqlite3DropTriggerPtr(A,B)
# define sqlite3UnlinkAndDeleteTrigger(A,B,C)
# define sqlite3CodeRowTrigger(A,B,C,D,E,F,G,H,I)
# define sqlite3CodeRowTriggerDirect(A,B,C,D,E,F)
# define sqlite3TriggerList(X, Y) 0
# define sqlite3ParseToplevel(p) p
# define sqlite3IsToplevel(p) 1
# define sqlite3TriggerColmask(A,B,C,D,E,F,G) 0
#endif

SQLITE_PRIVATE int sqlite3JoinType(Parse*, Token*, Token*, Token*);
SQLITE_PRIVATE void sqlite3CreateForeignKey(Parse*, ExprList*, Token*, ExprList*, int);
SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse*, int);
#ifndef SQLITE_OMIT_AUTHORIZATION

  rc = saveCursorKey(pCur);
  if( rc==SQLITE_OK ){
    btreeReleaseAllCursorPages(pCur);
    pCur->eState = CURSOR_REQUIRESEEK;
  }

  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl|BTCF_AtLast);
  return rc;
}

/* Forward reference */
static int SQLITE_NOINLINE saveCursorsOnList(BtCursor*,Pgno,BtCursor*);

/*

    ** for which the pointer is stored within the content being copied.
    **
    ** It is critical that the child page be defragmented before being
    ** copied into the parent, because if the parent is page 1 then it will
    ** by smaller than the child due to the database header, and so all the
    ** free space needs to be up front.
    */
    assert( nNew==1 || CORRUPT_DB );
    rc = defragmentPage(apNew[0]);
    testcase( rc!=SQLITE_OK );
    assert( apNew[0]->nFree == 
        (get2byte(&apNew[0]->aData[5])-apNew[0]->cellOffset-apNew[0]->nCell*2)
      || rc!=SQLITE_OK
    );
    copyNodeContent(apNew[0], pParent, &rc);

        }
      }
#endif
      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
        int j;
        for(j=0; j<pIdx->nKeyCol; j++){
          /* FIXME: Be smarter about indexes that use expressions */
          if( pIdx->aiColumn[j]==iCol || pIdx->aiColumn[j]==XN_EXPR ){
            zFault = "indexed";
          }
        }
      }
      if( zFault ){
        sqlite3DbFree(db, zErr);
        zErr = sqlite3MPrintf(db, "cannot open %s column for writing", zFault);

  Parse *pParse,  /* The parsing context */
  Index *pIdx,    /* The index whose column is to be loaded */
  int iTabCur,    /* Cursor pointing to a table row */
  int iIdxCol,    /* The column of the index to be loaded */
  int regOut      /* Store the index column value in this register */
){
  i16 iTabCol = pIdx->aiColumn[iIdxCol];
  if( iTabCol==XN_EXPR ){




  assert( pIdx->aColExpr );
  assert( pIdx->aColExpr->nExpr>iIdxCol );
  pParse->iSelfTab = iTabCur;
  sqlite3ExprCode(pParse, pIdx->aColExpr->a[iIdxCol].pExpr, regOut);
  }else{
    sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pIdx->pTable, iTabCur,
                                    iTabCol, regOut);
  }
}

/*
** Generate code to extract the value of the iCol-th column of a table.
*/
SQLITE_PRIVATE void sqlite3ExprCodeGetColumnOfTable(
  Vdbe *v,        /* The VDBE under construction */

          OP_Transaction,                    /* Opcode */
          iDb,                               /* P1 */
          DbMaskTest(pParse->writeMask,iDb), /* P2 */
          pParse->cookieValue[iDb],          /* P3 */
          db->aDb[iDb].pSchema->iGeneration  /* P4 */
        );
        if( db->init.busy==0 ) sqlite3VdbeChangeP5(v, 1);
        VdbeComment((v,
              "usesStmtJournal=%d", pParse->mayAbort && pParse->isMultiWrite));
      }
#ifndef SQLITE_OMIT_VIRTUALTABLE
      for(i=0; i<pParse->nVtabLock; i++){
        char *vtab = (char *)sqlite3GetVTable(db, pParse->apVtabLock[i]);
        sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
      }
      pParse->nVtabLock = 0;

  }else{
    sortOrderMask = 0;    /* Ignore DESC */
  }

  /* Analyze the list of expressions that form the terms of the index and
  ** report any errors.  In the common case where the expression is exactly
  ** a table column, store that column in aiColumn[].  For general expressions,
  ** populate pIndex->aColExpr and store XN_EXPR (-2) in aiColumn[].
  **
  ** TODO: Issue a warning if two or more columns of the index are identical.
  ** TODO: Issue a warning if the table primary key is used as part of the
  ** index key.
  */
  for(i=0, pListItem=pList->a; i<pList->nExpr; i++, pListItem++){
    Expr *pCExpr;                  /* The i-th index expression */

        ExprList *pCopy = sqlite3ExprListDup(db, pList, 0);
        pIndex->aColExpr = pCopy;
        if( !db->mallocFailed ){
          assert( pCopy!=0 );
          pListItem = &pCopy->a[i];
        }
      }
      j = XN_EXPR;
      pIndex->aiColumn[i] = XN_EXPR;
      pIndex->uniqNotNull = 0;
    }else{
      j = pCExpr->iColumn;
      assert( j<=0x7fff );
      if( j<0 ){
        j = pTab->iPKey;
      }else if( pTab->aCol[j].notNull==0 ){

        pIndex->azColl[i] = pPk->azColl[j];
        pIndex->aSortOrder[i] = pPk->aSortOrder[j];
        i++;
      }
    }
    assert( i==pIndex->nColumn );
  }else{
    pIndex->aiColumn[i] = XN_ROWID;
    pIndex->azColl[i] = "BINARY";
  }
  sqlite3DefaultRowEst(pIndex);
  if( pParse->pNewTable==0 ) estimateIndexWidth(pIndex);

  if( pTab==pParse->pNewTable ){
    /* This routine has been called to create an automatic index as a

    **  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);
    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 );
  
    /* Keep track of the number of rows to be deleted */
    if( db->flags & SQLITE_CountRows ){
      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
    }
  
    /* Extract the rowid or primary key for the current row */
    if( pPk ){
      for(i=0; i<nPk; i++){
        assert( pPk->aiColumn[i]>=0 );
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur,
                                        pPk->aiColumn[i], iPk+i);
      }
      iKey = iPk;
    }else{
      iKey = pParse->nMem + 1;
      iKey = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iTabCur, iKey, 0);

    }
  
    /* Set up a loop over the rowids/primary-keys that were found in the
    ** where-clause loop above.
    */
    if( eOnePass!=ONEPASS_OFF ){
      assert( nKey==nPk );  /* OP_Found will use an unpacked key */
      if( !IsVirtual(pTab) && aToOpen[iDataCur-iTabCur] ){
        assert( pPk!=0 || pTab->pSelect!=0 );
        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey);
        VdbeCoverage(v);
      }
    }else if( pPk ){
      addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur); VdbeCoverage(v);
      sqlite3VdbeAddOp2(v, OP_RowKey, iEphCur, iKey);

    /* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
      sqlite3VtabMakeWritable(pParse, pTab);
      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iKey, pVTab, P4_VTAB);
      sqlite3VdbeChangeP5(v, OE_Abort);
      assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE );
      sqlite3MayAbort(pParse);
      if( eOnePass==ONEPASS_SINGLE && sqlite3IsToplevel(pParse) ){
        pParse->isMultiWrite = 0;
      }
    }else
#endif
    {
      int count = (pParse->nested==0);    /* True to count changes */
      int iIdxNoSeek = -1;
      if( bComplex==0 && aiCurOnePass[1]!=iDataCur ){
        iIdxNoSeek = aiCurOnePass[1];

  }
  nCol = (prefixOnly && pIdx->uniqNotNull) ? pIdx->nKeyCol : pIdx->nColumn;
  regBase = sqlite3GetTempRange(pParse, nCol);
  if( pPrior && (regBase!=regPrior || pPrior->pPartIdxWhere) ) pPrior = 0;
  for(j=0; j<nCol; j++){
    if( pPrior
     && pPrior->aiColumn[j]==pIdx->aiColumn[j]
     && pPrior->aiColumn[j]!=XN_EXPR
    ){
      /* This column was already computed by the previous index */
      continue;
    }
    sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iDataCur, j, regBase+j);
    /* If the column affinity is REAL but the number is an integer, then it
    ** might be stored in the table as an integer (using a compact

        ** the default collation sequences for each column. */
        int i, j;
        for(i=0; i<nCol; i++){
          i16 iCol = pIdx->aiColumn[i];     /* Index of column in parent tbl */
          char *zDfltColl;                  /* Def. collation for column */
          char *zIdxCol;                    /* Name of indexed column */

          if( iCol<0 ) break; /* No foreign keys against expression indexes */

          /* If the index uses a collation sequence that is different from
          ** the default collation sequence for the column, this index is
          ** unusable. Bail out early in this case.  */
          zDfltColl = pParent->aCol[iCol].zColl;
          if( !zDfltColl ){
            zDfltColl = "BINARY";
          }

      ** none of the child key values are).
      */
      if( pTab==pFKey->pFrom && nIncr==1 ){
        int iJump = sqlite3VdbeCurrentAddr(v) + nCol + 1;
        for(i=0; i<nCol; i++){
          int iChild = aiCol[i]+1+regData;
          int iParent = pIdx->aiColumn[i]+1+regData;
          assert( pIdx->aiColumn[i]>=0 );
          assert( aiCol[i]!=pTab->iPKey );
          if( pIdx->aiColumn[i]==pTab->iPKey ){
            /* The parent key is a composite key that includes the IPK column */
            iParent = regData;
          }
          sqlite3VdbeAddOp3(v, OP_Ne, iChild, iJump, iParent); VdbeCoverage(v);
          sqlite3VdbeChangeP5(v, SQLITE_JUMPIFNULL);

      pNe = sqlite3PExpr(pParse, TK_NE, pLeft, pRight, 0);
    }else{
      Expr *pEq, *pAll = 0;
      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
      assert( pIdx!=0 );
      for(i=0; i<pPk->nKeyCol; i++){
        i16 iCol = pIdx->aiColumn[i];
        assert( iCol>=0 );
        pLeft = exprTableRegister(pParse, pTab, regData, iCol);
        pRight = exprTableColumn(db, pTab, pSrc->a[0].iCursor, iCol);
        pEq = sqlite3PExpr(pParse, TK_EQ, pLeft, pRight, 0);
        pAll = sqlite3ExprAnd(db, pAll, pEq);
      }
      pNe = sqlite3PExpr(pParse, TK_NOT, pAll, 0, 0);
    }

      iCol = pFKey->aCol[0].iFrom;
      aiCol = &iCol;
    }
    for(i=0; i<pFKey->nCol; i++){
      if( aiCol[i]==pTab->iPKey ){
        aiCol[i] = -1;
      }
      assert( pIdx==0 || pIdx->aiColumn[i]>=0 );
#ifndef SQLITE_OMIT_AUTHORIZATION
      /* Request permission to read the parent key columns. If the 
      ** authorization callback returns SQLITE_IGNORE, behave as if any
      ** values read from the parent table are NULL. */
      if( db->xAuth ){
        int rcauth;
        char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zName;

    for(p=pTab->pFKey; p; p=p->pNextFrom){
      for(i=0; i<p->nCol; i++) mask |= COLUMN_MASK(p->aCol[i].iFrom);
    }
    for(p=sqlite3FkReferences(pTab); p; p=p->pNextTo){
      Index *pIdx = 0;
      sqlite3FkLocateIndex(pParse, pTab, p, &pIdx, 0);
      if( pIdx ){
        for(i=0; i<pIdx->nKeyCol; i++){
          assert( pIdx->aiColumn[i]>=0 );
          mask |= COLUMN_MASK(pIdx->aiColumn[i]);
        }
      }
    }
  }
  return mask;
}

      Token tToCol;               /* Name of column in parent table */
      int iFromCol;               /* Idx of column in child table */
      Expr *pEq;                  /* tFromCol = OLD.tToCol */

      iFromCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
      assert( iFromCol>=0 );
      assert( pIdx!=0 || (pTab->iPKey>=0 && pTab->iPKey<pTab->nCol) );
      assert( pIdx==0 || pIdx->aiColumn[i]>=0 );
      tToCol.z = pTab->aCol[pIdx ? pIdx->aiColumn[i] : pTab->iPKey].zName;
      tFromCol.z = pFKey->pFrom->aCol[iFromCol].zName;

      tToCol.n = sqlite3Strlen30(tToCol.z);
      tFromCol.n = sqlite3Strlen30(tFromCol.z);

      /* Create the expression "OLD.zToCol = zFromCol". It is important

      db->mallocFailed = 1;
      return 0;
    }
    for(n=0; n<pIdx->nColumn; n++){
      i16 x = pIdx->aiColumn[n];
      if( x>=0 ){
        pIdx->zColAff[n] = pTab->aCol[x].affinity;
      }else if( x==XN_ROWID ){
        pIdx->zColAff[n] = SQLITE_AFF_INTEGER;
      }else{
        char aff;
        assert( x==XN_EXPR );
        assert( pIdx->aColExpr!=0 );
        aff = sqlite3ExprAffinity(pIdx->aColExpr->a[n].pExpr);
        if( aff==0 ) aff = SQLITE_AFF_BLOB;
        pIdx->zColAff[n] = aff;
      }
    }
    pIdx->zColAff[n] = 0;

  int memId;                 /* Register holding max rowid */
  int addr;                  /* A VDBE address */
  Vdbe *v = pParse->pVdbe;   /* VDBE under construction */

  /* This routine is never called during trigger-generation.  It is
  ** only called from the top-level */
  assert( pParse->pTriggerTab==0 );
  assert( sqlite3IsToplevel(pParse) );

  assert( v );   /* We failed long ago if this is not so */
  for(p = pParse->pAinc; p; p = p->pNext){
    pDb = &db->aDb[p->iDb];
    memId = p->regCtr;
    assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
    sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);

    /* Create a record for this index entry as it should appear after
    ** the insert or update.  Store that record in the aRegIdx[ix] register
    */
    regIdx = sqlite3GetTempRange(pParse, pIdx->nColumn);
    for(i=0; i<pIdx->nColumn; i++){
      int iField = pIdx->aiColumn[i];
      int x;
      if( iField==XN_EXPR ){
        pParse->ckBase = regNewData+1;
        sqlite3ExprCode(pParse, pIdx->aColExpr->a[i].pExpr, regIdx+i);
        pParse->ckBase = 0;
        VdbeComment((v, "%s column %d", pIdx->zName, i));
      }else{
        if( iField==XN_ROWID || iField==pTab->iPKey ){
          if( regRowid==regIdx+i ) continue; /* ROWID already in regIdx+i */
          x = regNewData;
          regRowid =  pIdx->pPartIdxWhere ? -1 : regIdx+i;
        }else{
          x = iField + regNewData + 1;
        }
        sqlite3VdbeAddOp2(v, OP_SCopy, x, regIdx+i);

        }
      }else{
        int x;
        /* Extract the PRIMARY KEY from the end of the index entry and
        ** store it in registers regR..regR+nPk-1 */
        if( pIdx!=pPk ){
          for(i=0; i<pPk->nKeyCol; i++){
            assert( pPk->aiColumn[i]>=0 );
            x = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[i]);
            sqlite3VdbeAddOp3(v, OP_Column, iThisCur, x, regR+i);
            VdbeComment((v, "%s.%s", pTab->zName,
                         pTab->aCol[pPk->aiColumn[i]].zName));
          }
        }
        if( isUpdate ){

          int addrJump = sqlite3VdbeCurrentAddr(v)+pPk->nKeyCol;
          int op = OP_Ne;
          int regCmp = (IsPrimaryKeyIndex(pIdx) ? regIdx : regR);
  
          for(i=0; i<pPk->nKeyCol; i++){
            char *p4 = (char*)sqlite3LocateCollSeq(pParse, pPk->azColl[i]);
            x = pPk->aiColumn[i];
            assert( x>=0 );
            if( i==(pPk->nKeyCol-1) ){
              addrJump = addrUniqueOk;
              op = OP_Eq;
            }
            sqlite3VdbeAddOp4(v, op, 
                regOldData+1+x, addrJump, regCmp+i, p4, P4_COLLSEQ
            );

  if( pDest->onError!=pSrc->onError ){
    return 0;   /* Different conflict resolution strategies */
  }
  for(i=0; i<pSrc->nKeyCol; i++){
    if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
      return 0;   /* Different columns indexed */
    }
    if( pSrc->aiColumn[i]==XN_EXPR ){
      assert( pSrc->aColExpr!=0 && pDest->aColExpr!=0 );
      if( sqlite3ExprCompare(pSrc->aColExpr->a[i].pExpr,
                             pDest->aColExpr->a[i].pExpr, -1)!=0 ){
        return 0;   /* Different expressions in the index */
      }
    }
    if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){

          ** or (2) the next entry has a different key */
          if( IsUniqueIndex(pIdx) ){
            int uniqOk = sqlite3VdbeMakeLabel(v);
            int jmp6;
            int kk;
            for(kk=0; kk<pIdx->nKeyCol; kk++){
              int iCol = pIdx->aiColumn[kk];
              assert( iCol!=XN_ROWID && iCol<pTab->nCol );
              if( iCol>=0 && pTab->aCol[iCol].notNull ) continue;
              sqlite3VdbeAddOp2(v, OP_IsNull, r1+kk, uniqOk);
              VdbeCoverage(v);
            }
            jmp6 = sqlite3VdbeAddOp1(v, OP_Next, iIdxCur+j); VdbeCoverage(v);
            sqlite3VdbeGoto(v, uniqOk);
            sqlite3VdbeJumpHere(v, jmp6);

  /* Look up every table named in the FROM clause of the select.  If
  ** an entry of the FROM clause is a subquery instead of a table or view,
  ** then create a transient table structure to describe the subquery.
  */
  for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
    Table *pTab;
    assert( pFrom->fg.isRecursive==0 || pFrom->pTab!=0 );
    if( pFrom->fg.isRecursive ) continue;



    assert( pFrom->pTab==0 );





#ifndef SQLITE_OMIT_CTE
    if( withExpand(pWalker, pFrom) ) return WRC_Abort;
    if( pFrom->pTab ) {} else
#endif
    if( pFrom->zName==0 ){
#ifndef SQLITE_OMIT_SUBQUERY
      Select *pSel = pFrom->pSelect;

static void selectAddSubqueryTypeInfo(Walker *pWalker, Select *p){
  Parse *pParse;
  int i;
  SrcList *pTabList;
  struct SrcList_item *pFrom;

  assert( p->selFlags & SF_Resolved );
  assert( (p->selFlags & SF_HasTypeInfo)==0 );
    p->selFlags |= SF_HasTypeInfo;
    pParse = pWalker->pParse;
    pTabList = p->pSrc;
    for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
      Table *pTab = pFrom->pTab;
    assert( pTab!=0 );
    if( (pTab->tabFlags & TF_Ephemeral)!=0 ){
        /* A sub-query in the FROM clause of a SELECT */
        Select *pSel = pFrom->pSelect;
        if( pSel ){
          while( pSel->pPrior ) pSel = pSel->pPrior;
          selectAddColumnTypeAndCollation(pParse, pTab, pSel);
        }
      }
    }
  }

#endif


/*
** This routine adds datatype and collating sequence information to
** the Table structures of all FROM-clause subqueries in a
** SELECT statement.

  int newmask;           /* Mask of NEW.* columns accessed by BEFORE triggers */
  int iEph = 0;          /* Ephemeral table holding all primary key values */
  int nKey = 0;          /* Number of elements in regKey for WITHOUT ROWID */
  int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */

  /* Register Allocations */
  int regRowCount = 0;   /* A count of rows changed */
  int regOldRowid = 0;   /* The old rowid */
  int regNewRowid = 0;   /* The new rowid */
  int regNew = 0;        /* Content of the NEW.* table in triggers */
  int regOld = 0;        /* Content of OLD.* table in triggers */
  int regRowSet = 0;     /* Rowset of rows to be updated */
  int regKey = 0;        /* composite PRIMARY KEY value */

  memset(&sContext, 0, sizeof(sContext));
  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ){

  /* Begin generating code. */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto update_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);












  /* Allocate required registers. */
  if( !IsVirtual(pTab) ){
  regRowSet = ++pParse->nMem;
  regOldRowid = regNewRowid = ++pParse->nMem;
  if( chngPk || pTrigger || hasFK ){
    regOld = pParse->nMem + 1;
    pParse->nMem += pTab->nCol;
  }
  if( chngKey || pTrigger || hasFK ){
    regNewRowid = ++pParse->nMem;
  }
  regNew = pParse->nMem + 1;
  pParse->nMem += pTab->nCol;
  }

  /* Start the view context. */
  if( isView ){
    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
  }

  /* If we are trying to update a view, realize that view into

  /* Resolve the column names in all the expressions in the
  ** WHERE clause.
  */
  if( sqlite3ResolveExprNames(&sNC, pWhere) ){
    goto update_cleanup;
  }

#ifndef SQLITE_OMIT_VIRTUALTABLE
  /* Virtual tables must be handled separately */
  if( IsVirtual(pTab) ){
    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
                       pWhere, onError);
    goto update_cleanup;
  }
#endif

  /* Begin the database scan
  */
  if( HasRowid(pTab) ){
    sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
    pWInfo = sqlite3WhereBegin(
        pParse, pTabList, pWhere, 0, 0, WHERE_ONEPASS_DESIRED, iIdxCur

    addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nPk);
    sqlite3VdbeSetP4KeyInfo(pParse, pPk);
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, 
                               WHERE_ONEPASS_DESIRED, iIdxCur);
    if( pWInfo==0 ) goto update_cleanup;
    okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
    for(i=0; i<nPk; i++){
      assert( pPk->aiColumn[i]>=0 );
      sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, pPk->aiColumn[i],
                                      iPk+i);
    }
    if( okOnePass ){
      sqlite3VdbeChangeToNoop(v, addrOpen);
      nKey = nPk;
      regKey = iPk;

  ** the database after the BEFORE triggers are fired anyway (as the trigger 
  ** may have modified them). So not loading those that are not going to
  ** be used eliminates some redundant opcodes.
  */
  newmask = sqlite3TriggerColmask(
      pParse, pTrigger, pChanges, 1, TRIGGER_BEFORE, pTab, onError
  );

  for(i=0; i<pTab->nCol; i++){
    if( i==pTab->iPKey ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
    }else{
      j = aXRef[i];
      if( j>=0 ){
        sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regNew+i);

 #undef pTrigger
#endif

#ifndef SQLITE_OMIT_VIRTUALTABLE
/*
** Generate code for an UPDATE of a virtual table.
**
** There are two possible strategies - the default and the special 
** "onepass" strategy. Onepass is only used if the virtual table 
** implementation indicates that pWhere may match at most one row.
**
** The default strategy is to create an ephemeral table that contains
** for each row to be changed:
**
**   (A)  The original rowid of that row.
**   (B)  The revised rowid for the row.
**   (C)  The content of every column in the row.
**
** Then loop through the contents of this ephemeral table executing a


** VUpdate for each row. When finished, drop the ephemeral table.
**
** The "onepass" strategy does not use an ephemeral table. Instead, it
** stores the same values (A, B and C above) in a register array and

** makes a single invocation of VUpdate.
*/
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */
  SrcList *pSrc,       /* The virtual table to be modified */
  Table *pTab,         /* The virtual table */
  ExprList *pChanges,  /* The columns to change in the UPDATE statement */
  Expr *pRowid,        /* Expression used to recompute the rowid */
  int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
  Expr *pWhere,        /* WHERE clause of the UPDATE statement */
  int onError          /* ON CONFLICT strategy */
){
  Vdbe *v = pParse->pVdbe;  /* Virtual machine under construction */



  int ephemTab;             /* Table holding the result of the SELECT */
  int i;                    /* Loop counter */


  sqlite3 *db = pParse->db; /* Database connection */
  const char *pVTab = (const char*)sqlite3GetVTable(db, pTab);
  WhereInfo *pWInfo;
  int nArg = 2 + pTab->nCol;      /* Number of arguments to VUpdate */
  int regArg;                     /* First register in VUpdate arg array */
  int regRec;                     /* Register in which to assemble record */
  int regRowid;                   /* Register for ephem table rowid */
  int iCsr = pSrc->a[0].iCursor;  /* Cursor used for virtual table scan */
  int aDummy[2];                  /* Unused arg for sqlite3WhereOkOnePass() */
  int bOnePass;                   /* True to use onepass strategy */
  int addr;                       /* Address of OP_OpenEphemeral */

  /* Allocate nArg registers to martial the arguments to VUpdate. Then
  ** create and open the ephemeral table in which the records created from
  ** these arguments will be temporarily stored. */
  assert( v );
  ephemTab = pParse->nTab++;
  addr= sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, nArg);
  regArg = pParse->nMem + 1;
  pParse->nMem += nArg;
  regRec = ++pParse->nMem;
  regRowid = ++pParse->nMem;

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

  /* Populate the argument registers. */
  sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg);
  if( pRowid ){
    sqlite3ExprCode(pParse, pRowid, regArg+1);
  }else{
    sqlite3VdbeAddOp2(v, OP_Rowid, iCsr, regArg+1);
  }

  for(i=0; i<pTab->nCol; i++){
    if( aXRef[i]>=0 ){
      sqlite3ExprCode(pParse, pChanges->a[aXRef[i]].pExpr, regArg+2+i);
    }else{
      sqlite3VdbeAddOp3(v, OP_VColumn, iCsr, i, regArg+2+i);
    }

  }

  bOnePass = sqlite3WhereOkOnePass(pWInfo, aDummy);
  



  if( bOnePass ){
    /* If using the onepass strategy, no-op out the OP_OpenEphemeral coded
    ** above. Also, if this is a top-level parse (not a trigger), clear the
    ** multi-write flag so that the VM does not open a statement journal */
    sqlite3VdbeChangeToNoop(v, addr);
    if( sqlite3IsToplevel(pParse) ){
      pParse->isMultiWrite = 0;
    }
  }else{
    /* Create a record from the argument register contents and insert it into
    ** the ephemeral table. */

    sqlite3VdbeAddOp3(v, OP_MakeRecord, regArg, nArg, regRec);
    sqlite3VdbeAddOp2(v, OP_NewRowid, ephemTab, regRowid);
    sqlite3VdbeAddOp3(v, OP_Insert, ephemTab, regRec, regRowid);
  }


  if( bOnePass==0 ){
    /* End the virtual table scan */
    sqlite3WhereEnd(pWInfo);

    /* Begin scannning through the ephemeral table. */
    addr = sqlite3VdbeAddOp1(v, OP_Rewind, ephemTab); VdbeCoverage(v);


    /* Extract arguments from the current row of the ephemeral table and 
    ** invoke the VUpdate method.  */
    for(i=0; i<nArg; i++){
      sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i, regArg+i);
  }
  }
  sqlite3VtabMakeWritable(pParse, pTab);
  sqlite3VdbeAddOp4(v, OP_VUpdate, 0, nArg, regArg, pVTab, P4_VTAB);
  sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
  sqlite3MayAbort(pParse);

  /* End of the ephemeral table scan. Or, if using the onepass strategy,
  ** jump to here if the scan visited zero rows. */
  if( bOnePass==0 ){
  sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1); VdbeCoverage(v);
  sqlite3VdbeJumpHere(v, addr);
  sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
  }else{
    sqlite3WhereEnd(pWInfo);
  }


}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

/************** End of update.c **********************************************/
/************** Begin file vacuum.c ******************************************/
/*
** 2003 April 6

    /* Invoke the xBegin method. If successful, add the vtab to the 
    ** sqlite3.aVTrans[] array. */
    rc = growVTrans(db);
    if( rc==SQLITE_OK ){
      rc = pModule->xBegin(pVTab->pVtab);
      if( rc==SQLITE_OK ){
        int iSvpt = db->nStatement + db->nSavepoint;
        addToVTrans(db, pVTab);
        if( iSvpt ) rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN, iSvpt-1);
      }
    }
  }
  return rc;
}

/*

}

/*
** Return the name of the i-th column of the pIdx index.
*/
static const char *explainIndexColumnName(Index *pIdx, int i){
  i = pIdx->aiColumn[i];
  if( i==XN_EXPR ) return "<expr>";
  if( i==XN_ROWID ) return "rowid";
  return pIdx->pTable->aCol[i].zName;
}

/*
** Argument pLevel describes a strategy for scanning table pTab. This 
** function appends text to pStr that describes the subset of table
** rows scanned by the strategy in the form of an SQL expression.

    pLevel->addrSkip = sqlite3VdbeAddOp4Int(v, (bRev?OP_SeekLT:OP_SeekGT),
                            iIdxCur, 0, regBase, nSkip);
    VdbeCoverageIf(v, bRev==0);
    VdbeCoverageIf(v, bRev!=0);
    sqlite3VdbeJumpHere(v, j);
    for(j=0; j<nSkip; j++){
      sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, j, regBase+j);
      testcase( pIdx->aiColumn[j]==XN_EXPR );
      VdbeComment((v, "%s", explainIndexColumnName(pIdx, j)));
    }
  }    

  /* Evaluate the equality constraints
  */
  assert( zAff==0 || (int)strlen(zAff)>=nEq );

    VdbeCoverage(v);
    pLoop->u.vtab.needFree = 0;
    for(j=0; j<nConstraint && j<16; j++){
      if( (pLoop->u.vtab.omitMask>>j)&1 ){
        disableTerm(pLevel, pLoop->aLTerm[j]);
      }
    }

    pLevel->p1 = iCur;
    pLevel->op = pWInfo->eOnePass ? OP_Noop : OP_VNext;
    pLevel->p2 = sqlite3VdbeCurrentAddr(v);
    sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2);
    sqlite3ExprCachePop(pParse);
  }else
#endif /* SQLITE_OMIT_VIRTUALTABLE */

  if( (pLoop->wsFlags & WHERE_IPK)!=0

  WhereClause *pWC;    /* Shorthand for pScan->pWC */
  WhereTerm *pTerm;    /* The term being tested */
  int k = pScan->k;    /* Where to start scanning */

  while( pScan->iEquiv<=pScan->nEquiv ){
    iCur = pScan->aiCur[pScan->iEquiv-1];
    iColumn = pScan->aiColumn[pScan->iEquiv-1];
    if( iColumn==XN_EXPR && pScan->pIdxExpr==0 ) return 0;
    while( (pWC = pScan->pWC)!=0 ){
      for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
        if( pTerm->leftCursor==iCur
         && pTerm->u.leftColumn==iColumn
         && (iColumn!=XN_EXPR
             || sqlite3ExprCompare(pTerm->pExpr->pLeft,pScan->pIdxExpr,iCur)==0)
         && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_FromJoin))
        ){
          if( (pTerm->eOperator & WO_EQUIV)!=0
           && pScan->nEquiv<ArraySize(pScan->aiCur)
           && (pX = sqlite3ExprSkipCollate(pTerm->pExpr->pRight))->op==TK_COLUMN
          ){

  /* memset(pScan, 0, sizeof(*pScan)); */
  pScan->pOrigWC = pWC;
  pScan->pWC = pWC;
  pScan->pIdxExpr = 0;
  if( pIdx ){
    j = iColumn;
    iColumn = pIdx->aiColumn[j];
    if( iColumn==XN_EXPR ) pScan->pIdxExpr = pIdx->aColExpr->a[j].pExpr;
  }
  if( pIdx && iColumn>=0 ){
    pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity;
    pScan->zCollName = pIdx->azColl[j];
  }else{
    pScan->idxaff = 0;
    pScan->zCollName = 0;

    for(i=BMS-1; i<pTable->nCol; i++){
      pIdx->aiColumn[n] = i;
      pIdx->azColl[n] = "BINARY";
      n++;
    }
  }
  assert( n==nKeyCol );
  pIdx->aiColumn[n] = XN_ROWID;
  pIdx->azColl[n] = "BINARY";

  /* Create the automatic index */
  assert( pLevel->iIdxCur>=0 );
  pLevel->iIdxCur = pParse->nTab++;
  sqlite3VdbeAddOp2(v, OP_OpenAutoindex, pLevel->iIdxCur, nKeyCol+1);
  sqlite3VdbeSetP4KeyInfo(pParse, pIdx);

      assert( nIn>0 );  /* RHS always has 2 or more terms...  The parser
                        ** changes "x IN (?)" into "x=?". */

    }else if( eOp & (WO_EQ|WO_IS) ){
      int iCol = pProbe->aiColumn[saved_nEq];
      pNew->wsFlags |= WHERE_COLUMN_EQ;
      assert( saved_nEq==pNew->u.btree.nEq );
      if( iCol==XN_ROWID 
       || (iCol>0 && nInMul==0 && saved_nEq==pProbe->nKeyCol-1)
      ){
        if( iCol>=0 && pProbe->uniqNotNull==0 ){
          pNew->wsFlags |= WHERE_UNQ_WANTED;
        }else{
          pNew->wsFlags |= WHERE_ONEROW;
        }
      }
    }else if( eOp & WO_ISNULL ){

    if( pExpr->op==TK_COLUMN && pExpr->iTable==iCursor ){
      if( pExpr->iColumn<0 ) return 1;
      for(jj=0; jj<pIndex->nKeyCol; jj++){
        if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
      }
    }else if( (aColExpr = pIndex->aColExpr)!=0 ){
      for(jj=0; jj<pIndex->nKeyCol; jj++){
        if( pIndex->aiColumn[jj]!=XN_EXPR ) continue;
        if( sqlite3ExprCompare(pExpr,aColExpr->a[jj].pExpr,iCursor)==0 ){
          return 1;
        }
      }
    }
  }
  return 0;

    if( pIdxInfo->needToFreeIdxStr ) sqlite3_free(pIdxInfo->idxStr);
    pIdxInfo->idxStr = 0;
    pIdxInfo->idxNum = 0;
    pIdxInfo->needToFreeIdxStr = 0;
    pIdxInfo->orderByConsumed = 0;
    pIdxInfo->estimatedCost = SQLITE_BIG_DBL / (double)2;
    pIdxInfo->estimatedRows = 25;
    pIdxInfo->idxFlags = 0;
    rc = vtabBestIndex(pParse, pTab, pIdxInfo);
    if( rc ) goto whereLoopAddVtab_exit;
    pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint;
    pNew->prereq = mExtra;
    mxTerm = -1;
    assert( pNew->nLSlot>=nConstraint );
    for(i=0; i<nConstraint; i++) pNew->aLTerm[i] = 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;
        }
      }
    }
    if( i>=nConstraint ){
      pNew->nLTerm = mxTerm+1;
      assert( pNew->nLTerm<=pNew->nLSlot );
      pNew->u.vtab.idxNum = pIdxInfo->idxNum;
      pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
      pIdxInfo->needToFreeIdxStr = 0;
      pNew->u.vtab.idxStr = pIdxInfo->idxStr;
      pNew->u.vtab.isOrdered = (i8)(pIdxInfo->orderByConsumed ?
                                      pIdxInfo->nOrderBy : 0);
      pNew->rSetup = 0;
      pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost);
      pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows);

      /* Set the WHERE_ONEROW flag if the xBestIndex() method indicated
      ** that the scan will visit at most one row. Clear it otherwise. */
      if( pIdxInfo->idxFlags & SQLITE_INDEX_SCAN_UNIQUE ){
        pNew->wsFlags |= WHERE_ONEROW;
      }else{
        pNew->wsFlags &= ~WHERE_ONEROW;
      }
      whereLoopInsert(pBuilder, pNew);
      if( pNew->u.vtab.needFree ){
        sqlite3_free(pNew->u.vtab.idxStr);
        pNew->u.vtab.needFree = 0;
      }
    }
  }  

        nColumn = 1;
      }else if( (pIndex = pLoop->u.btree.pIndex)==0 || pIndex->bUnordered ){
        return 0;
      }else{
        nKeyCol = pIndex->nKeyCol;
        nColumn = pIndex->nColumn;
        assert( nColumn==nKeyCol+1 || !HasRowid(pIndex->pTable) );
        assert( pIndex->aiColumn[nColumn-1]==XN_ROWID
                          || !HasRowid(pIndex->pTable));
        isOrderDistinct = IsUniqueIndex(pIndex);
      }

      /* Loop through all columns of the index and deal with the ones
      ** that are not constrained by == or IN.
      */
      rev = revSet = 0;

        ** (revIdx) for the j-th column of the index.
        */
        if( pIndex ){
          iColumn = pIndex->aiColumn[j];
          revIdx = pIndex->aSortOrder[j];
          if( iColumn==pIndex->pTable->iPKey ) iColumn = -1;
        }else{
          iColumn = XN_ROWID;
          revIdx = 0;
        }

        /* An unconstrained column that might be NULL means that this
        ** WhereLoop is not well-ordered
        */
        if( isOrderDistinct

        if( pOp->p1!=pLevel->iTabCur ) continue;
        if( pOp->opcode==OP_Column ){
          int x = pOp->p2;
          assert( pIdx->pTable==pTab );
          if( !HasRowid(pTab) ){
            Index *pPk = sqlite3PrimaryKeyIndex(pTab);
            x = pPk->aiColumn[x];
            assert( x>=0 );
          }
          x = sqlite3ColumnOfIndex(pIdx, x);
          if( x>=0 ){
            pOp->p2 = x;
            pOp->p1 = pLevel->iIdxCur;
          }
          assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 || x>=0 );

    int nPrefix;                  /* Prefix length (0 for main terms index) */
    Fts3Hash hPending;            /* Pending terms table for this index */
  } *aIndex;
  int nMaxPendingData;            /* Max pending data before flush to disk */
  int nPendingData;               /* Current bytes of pending data */
  sqlite_int64 iPrevDocid;        /* Docid of most recently inserted document */
  int iPrevLangid;                /* Langid of recently inserted document */
  int bPrevDelete;                /* True if last operation was a delete */

#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
  /* State variables used for validating that the transaction control
  ** methods of the virtual table are called at appropriate times.  These
  ** values do not contribute to FTS functionality; they are used for
  ** verifying the operation of the SQLite core.
  */

static void fts3SetEstimatedRows(sqlite3_index_info *pIdxInfo, i64 nRow){
#if SQLITE_VERSION_NUMBER>=3008002
  if( sqlite3_libversion_number()>=3008002 ){
    pIdxInfo->estimatedRows = nRow;
  }
#endif
}

/*
** Set the SQLITE_INDEX_SCAN_UNIQUE flag in pIdxInfo->flags. Unless this
** extension is currently being used by a version of SQLite too old to
** support index-info flags. In that case this function is a no-op.
*/
static void fts3SetUniqueFlag(sqlite3_index_info *pIdxInfo){
#if SQLITE_VERSION_NUMBER>=3008012
  if( sqlite3_libversion_number()>=3008012 ){
    pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_UNIQUE;
  }
#endif
}

/* 
** Implementation of the xBestIndex method for FTS3 tables. There
** are three possible strategies, in order of preference:
**
**   1. Direct lookup by rowid or docid. 
**   2. Full-text search using a MATCH operator on a non-docid column.

        case SQLITE_INDEX_CONSTRAINT_LE:
        case SQLITE_INDEX_CONSTRAINT_LT:
          iDocidLe = i;
          break;
      }
    }
  }

  /* If using a docid=? or rowid=? strategy, set the UNIQUE flag. */
  if( pInfo->idxNum==FTS3_DOCID_SEARCH ) fts3SetUniqueFlag(pInfo);

  iIdx = 1;
  if( iCons>=0 ){
    pInfo->aConstraintUsage[iCons].argvIndex = iIdx++;
    pInfo->aConstraintUsage[iCons].omit = 1;
  } 
  if( iLangidCons>=0 ){

/* 
** Calling this function indicates that subsequent calls to 
** fts3PendingTermsAdd() are to add term/position-list pairs for the
** contents of the document with docid iDocid.
*/
static int fts3PendingTermsDocid(
  Fts3Table *p,                   /* Full-text table handle */
  int bDelete,                    /* True if this op is a delete */
  int iLangid,                    /* Language id of row being written */
  sqlite_int64 iDocid             /* Docid of row being written */
){
  assert( iLangid>=0 );
  assert( bDelete==1 || bDelete==0 );

  /* TODO(shess) Explore whether partially flushing the buffer on
  ** forced-flush would provide better performance.  I suspect that if
  ** we ordered the doclists by size and flushed the largest until the
  ** buffer was half empty, that would let the less frequent terms
  ** generate longer doclists.
  */
  if( iDocid<p->iPrevDocid 
   || (iDocid==p->iPrevDocid && p->bPrevDelete==0)
   || p->iPrevLangid!=iLangid
   || p->nPendingData>p->nMaxPendingData 
  ){
    int rc = sqlite3Fts3PendingTermsFlush(p);
    if( rc!=SQLITE_OK ) return rc;
  }
  p->iPrevDocid = iDocid;
  p->iPrevLangid = iLangid;
  p->bPrevDelete = bDelete;
  return SQLITE_OK;
}

/*
** Discard the contents of the pending-terms hash tables. 
*/
SQLITE_PRIVATE void sqlite3Fts3PendingTermsClear(Fts3Table *p){

  assert( *pbFound==0 );
  if( *pRC ) return;
  rc = fts3SqlStmt(p, SQL_SELECT_CONTENT_BY_ROWID, &pSelect, &pRowid);
  if( rc==SQLITE_OK ){
    if( SQLITE_ROW==sqlite3_step(pSelect) ){
      int i;
      int iLangid = langidFromSelect(p, pSelect);
      i64 iDocid = sqlite3_column_int64(pSelect, 0);
      rc = fts3PendingTermsDocid(p, 1, iLangid, iDocid);
      for(i=1; rc==SQLITE_OK && i<=p->nColumn; i++){
        int iCol = i-1;
        if( p->abNotindexed[iCol]==0 ){
          const char *zText = (const char *)sqlite3_column_text(pSelect, i);
          rc = fts3PendingTermsAdd(p, iLangid, zText, -1, &aSz[iCol]);
          aSz[p->nColumn] += sqlite3_column_bytes(pSelect, i);
        }

        aSzDel = &aSzIns[p->nColumn+1];
      }
    }

    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
      int iCol;
      int iLangid = langidFromSelect(p, pStmt);
      rc = fts3PendingTermsDocid(p, 0, iLangid, sqlite3_column_int64(pStmt, 0));
      memset(aSz, 0, sizeof(aSz[0]) * (p->nColumn+1));
      for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
        if( p->abNotindexed[iCol]==0 ){
          const char *z = (const char *) sqlite3_column_text(pStmt, iCol+1);
          rc = fts3PendingTermsAdd(p, iLangid, z, iCol, &aSz[iCol]);
          aSz[p->nColumn] += sqlite3_column_bytes(pStmt, iCol+1);
        }

    if( bInsertDone==0 ){
      rc = fts3InsertData(p, apVal, pRowid);
      if( rc==SQLITE_CONSTRAINT && p->zContentTbl==0 ){
        rc = FTS_CORRUPT_VTAB;
      }
    }
    if( rc==SQLITE_OK && (!isRemove || *pRowid!=p->iPrevDocid ) ){
      rc = fts3PendingTermsDocid(p, 0, iLangid, *pRowid);
    }
    if( rc==SQLITE_OK ){
      assert( p->iPrevDocid==*pRowid );
      rc = fts3InsertTerms(p, iLangid, apVal, aSzIns);
    }
    if( p->bHasDocsize ){
      fts3InsertDocsize(&rc, p, aSzIns);

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.8.12"
#define SQLITE_VERSION_NUMBER 3008012
#define SQLITE_SOURCE_ID      "2015-09-30 14:30:19 e796c0efb6cf17444b53af75046daf7d8fa82f78"

/*
** 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

** strategy. A cost of N indicates that the cost of the strategy is similar
** to a linear scan of an SQLite table with N rows. A cost of log(N) 
** indicates that the expense of the operation is similar to that of a
** binary search on a unique indexed field of an SQLite table with N rows.
**
** ^The estimatedRows value is an estimate of the number of rows that
** will be returned by the strategy.
**
** The xBestIndex method may optionally populate the idxFlags field with a 
** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
** assumes that the strategy may visit at most one row. 
**
** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
** SQLite also assumes that if a call to the xUpdate() method is made as
** part of the same statement to delete or update a virtual table row and the
** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
** any database changes. In other words, if the xUpdate() returns
** SQLITE_CONSTRAINT, the database contents must be exactly as they were
** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
** the xUpdate method are automatically rolled back by SQLite.
**
** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
** structure for SQLite version 3.8.2. If a virtual table extension is
** used with an SQLite version earlier than 3.8.2, the results of attempting 
** to read or write the estimatedRows field are undefined (but are likely 
** to included crashing the application). The estimatedRows field should
** therefore only be used if [sqlite3_libversion_number()] returns a
** value greater than or equal to 3008002. Similarly, the idxFlags field
** was added for version 3.8.12. It may therefore only be used if
** sqlite3_libversion_number() returns a value greater than or equal to
** 3008012.
*/
struct sqlite3_index_info {
  /* Inputs */
  int nConstraint;           /* Number of entries in aConstraint */
  struct sqlite3_index_constraint {
     int iColumn;              /* Column on left-hand side of constraint */
     unsigned char op;         /* Constraint operator */

  int idxNum;                /* Number used to identify the index */
  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
  int orderByConsumed;       /* True if output is already ordered */
  double estimatedCost;           /* Estimated cost of using this index */
  /* Fields below are only available in SQLite 3.8.2 and later */
  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
  /* Fields below are only available in SQLite 3.8.12 and later */
  int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
};

/*
** CAPI3REF: Virtual Table Scan Flags
*/
#define SQLITE_INDEX_SCAN_UNIQUE      1     /* Scan visits at most 1 row */

/*
** CAPI3REF: Virtual Table Constraint Operator Codes
**
** These macros defined 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
** a query that uses a [virtual table].

    int iRowidOff = 0;
    int iOff;
    int nDoclist;

    memset(&term, 0, sizeof(Fts5Buffer));

    if( n<4 ){
      sqlite3Fts5BufferSet(&rc, &s, 7, (const u8*)"corrupt");
      goto decode_out;
    }else{
      iRowidOff = fts5GetU16(&a[0]);
      iPgidxOff = szLeaf = fts5GetU16(&a[2]);
      if( iPgidxOff<n ){
        fts5GetVarint32(&a[iPgidxOff], iTermOff);
      }

*/
static void fts5SourceIdFunc(
  sqlite3_context *pCtx,          /* Function call context */
  int nArg,                       /* Number of args */
  sqlite3_value **apVal           /* Function arguments */
){
  assert( nArg==0 );
  sqlite3_result_text(pCtx, "fts5: 2015-09-30 14:30:19 e796c0efb6cf17444b53af75046daf7d8fa82f78", -1, SQLITE_TRANSIENT);
}

#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_fts5_init(
  sqlite3 *db,