}

/*
** Implementation of xSync() method. Flush the contents of the pending-terms
** hash-table to the database.
*/
static int fts3SyncMethod(sqlite3_vtab *pVtab){

  Fts3Table *p = (Fts3Table*)pVtab;
  int rc = sqlite3Fts3PendingTermsFlush(p);

  if( rc==SQLITE_OK && p->bAutoincrmerge==1 && p->nLeafAdd>0 ){





    int A = p->nLeafAdd * p->mxLevel;
    A += A/2;
    rc = sqlite3Fts3Incrmerge(p, A, 8);
  }
  sqlite3Fts3SegmentsClose(p);
  return rc;
}

/*
** Implementation of xBegin() method. This is a no-op.

}

/*
** Implementation of xSync() method. Flush the contents of the pending-terms
** hash-table to the database.
*/
static int fts3SyncMethod(sqlite3_vtab *pVtab){
  const int nMinMerge = 64;       /* Minimum amount of incr-merge work to do */
  Fts3Table *p = (Fts3Table*)pVtab;
  int rc = sqlite3Fts3PendingTermsFlush(p);

  if( rc==SQLITE_OK && p->bAutoincrmerge==1 && p->nLeafAdd>(nMinMerge/16) ){
    int mxLevel = 0;              /* Maximum relative level value in db */
    int A;                        /* Incr-merge parameter A */

    rc = sqlite3Fts3MaxLevel(p, &mxLevel);
    assert( rc==SQLITE_OK || mxLevel==0 );
    A = p->nLeafAdd * p->mxLevel;
    A += (A/2);
    if( A>nMinMerge ) rc = sqlite3Fts3Incrmerge(p, A, 8);
  }
  sqlite3Fts3SegmentsClose(p);
  return rc;
}

/*
** Implementation of xBegin() method. This is a no-op.

  u8 bAutoincrmerge;              /* True if automerge=1 */
  int mxLevel;                    /* Maximum level seen on this transaction */
  u32 nLeafAdd;                   /* Number of leaf blocks added this trans */

  /* Precompiled statements used by the implementation. Each of these 
  ** statements is run and reset within a single virtual table API call. 
  */
  sqlite3_stmt *aStmt[36];

  char *zReadExprlist;
  char *zWriteExprlist;

  int nNodeSize;                  /* Soft limit for node size */
  u8 bHasStat;                    /* True if %_stat table exists */
  u8 bHasDocsize;                 /* True if %_docsize table exists */
................................................................................
int sqlite3Fts3SelectDocsize(Fts3Table *, sqlite3_int64, sqlite3_stmt **);

void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *);
int sqlite3Fts3DeferToken(Fts3Cursor *, Fts3PhraseToken *, int);
int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *);
void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *);
void sqlite3Fts3SegmentsClose(Fts3Table *);


/* Special values interpreted by sqlite3SegReaderCursor() */
#define FTS3_SEGCURSOR_PENDING        -1
#define FTS3_SEGCURSOR_ALL            -2

int sqlite3Fts3SegReaderStart(Fts3Table*, Fts3MultiSegReader*, Fts3SegFilter*);
int sqlite3Fts3SegReaderStep(Fts3Table *, Fts3MultiSegReader *);

  u8 bAutoincrmerge;              /* True if automerge=1 */
  int mxLevel;                    /* Maximum level seen on this transaction */
  u32 nLeafAdd;                   /* Number of leaf blocks added this trans */

  /* Precompiled statements used by the implementation. Each of these 
  ** statements is run and reset within a single virtual table API call. 
  */
  sqlite3_stmt *aStmt[37];

  char *zReadExprlist;
  char *zWriteExprlist;

  int nNodeSize;                  /* Soft limit for node size */
  u8 bHasStat;                    /* True if %_stat table exists */
  u8 bHasDocsize;                 /* True if %_docsize table exists */
................................................................................
int sqlite3Fts3SelectDocsize(Fts3Table *, sqlite3_int64, sqlite3_stmt **);

void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *);
int sqlite3Fts3DeferToken(Fts3Cursor *, Fts3PhraseToken *, int);
int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *);
void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *);
void sqlite3Fts3SegmentsClose(Fts3Table *);
int sqlite3Fts3MaxLevel(Fts3Table *, int *);

/* Special values interpreted by sqlite3SegReaderCursor() */
#define FTS3_SEGCURSOR_PENDING        -1
#define FTS3_SEGCURSOR_ALL            -2

int sqlite3Fts3SegReaderStart(Fts3Table*, Fts3MultiSegReader*, Fts3SegFilter*);
int sqlite3Fts3SegReaderStep(Fts3Table *, Fts3MultiSegReader *);

#define SQL_MAX_LEAF_NODE_ESTIMATE    29
#define SQL_DELETE_SEGDIR_ENTRY       30
#define SQL_SHIFT_SEGDIR_ENTRY        31
#define SQL_SELECT_SEGDIR             32
#define SQL_CHOMP_SEGDIR              33
#define SQL_SEGMENT_IS_APPENDABLE     34
#define SQL_SELECT_INDEXES            35


/*
** This function is used to obtain an SQLite prepared statement handle
** for the statement identified by the second argument. If successful,
** *pp is set to the requested statement handle and SQLITE_OK returned.
** Otherwise, an SQLite error code is returned and *pp is set to 0.
**
................................................................................
/* SQL_SEGMENT_IS_APPENDABLE
**   Return a single row if the segment with end_block=? is appendable. Or
**   no rows otherwise.  */
/* 34 */  "SELECT 1 FROM %Q.'%q_segments' WHERE blockid=? AND block IS NULL",

/* SQL_SELECT_INDEXES
**   Return the list of valid segment indexes for absolute level ?  */
/* 35 */  "SELECT idx FROM %Q.'%q_segdir' WHERE level=? ORDER BY 1 ASC"




  };
  int rc = SQLITE_OK;
  sqlite3_stmt *pStmt;

  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
  
................................................................................
/*
** Update the Fts3Table.mxLevel field, if appropriate
*/
static void fts3UpdateMaxLevel(Fts3Table *p, sqlite3_int64 iLevel){
  iLevel %= FTS3_SEGDIR_MAXLEVEL;
  if( iLevel>p->mxLevel ) p->mxLevel = iLevel;
}






















/* 
** Insert a record into the %_segdir table.
*/
static int fts3WriteSegdir(
  Fts3Table *p,                   /* Virtual table handle */
  sqlite3_int64 iLevel,           /* Value for "level" field (absolute level) */
................................................................................

  if( nData>0 && nData+nReq>p->nNodeSize ){
    int rc;

    /* The current leaf node is full. Write it out to the database. */
    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, nData);
    if( rc!=SQLITE_OK ) return rc;


    /* Add the current term to the interior node tree. The term added to
    ** the interior tree must:
    **
    **   a) be greater than the largest term on the leaf node just written
    **      to the database (still available in pWriter->zTerm), and
    **
................................................................................
          p, iLevel, iIdx, pWriter->iFirst, iLastLeaf, iLast, zRoot, nRoot);
    }
  }else{
    /* The entire tree fits on the root node. Write it to the segdir table. */
    rc = fts3WriteSegdir(
        p, iLevel, iIdx, 0, 0, 0, pWriter->aData, pWriter->nData);
  }

  return rc;
}

/*
** Release all memory held by the SegmentWriter object passed as the 
** first argument.
*/
................................................................................
/* 
** Flush the contents of pendingTerms to level 0 segments.
*/
int sqlite3Fts3PendingTermsFlush(Fts3Table *p){
  int rc = SQLITE_OK;
  int i;
        
  p->nLeafAdd += (p->nPendingData + p->nNodeSize - 1)/p->nNodeSize;
  for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
    rc = fts3SegmentMerge(p, p->iPrevLangid, i, FTS3_SEGCURSOR_PENDING);
    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
  }
  sqlite3Fts3PendingTermsClear(p);

  /* Determine the auto-incr-merge setting if unknown.  If enabled,

#define SQL_MAX_LEAF_NODE_ESTIMATE    29
#define SQL_DELETE_SEGDIR_ENTRY       30
#define SQL_SHIFT_SEGDIR_ENTRY        31
#define SQL_SELECT_SEGDIR             32
#define SQL_CHOMP_SEGDIR              33
#define SQL_SEGMENT_IS_APPENDABLE     34
#define SQL_SELECT_INDEXES            35
#define SQL_SELECT_MXLEVEL            36

/*
** This function is used to obtain an SQLite prepared statement handle
** for the statement identified by the second argument. If successful,
** *pp is set to the requested statement handle and SQLITE_OK returned.
** Otherwise, an SQLite error code is returned and *pp is set to 0.
**
................................................................................
/* SQL_SEGMENT_IS_APPENDABLE
**   Return a single row if the segment with end_block=? is appendable. Or
**   no rows otherwise.  */
/* 34 */  "SELECT 1 FROM %Q.'%q_segments' WHERE blockid=? AND block IS NULL",

/* SQL_SELECT_INDEXES
**   Return the list of valid segment indexes for absolute level ?  */
/* 35 */  "SELECT idx FROM %Q.'%q_segdir' WHERE level=? ORDER BY 1 ASC",

/* SQL_SELECT_MXLEVEL
**   Return the largest relative level in the FTS index or indexes.  */
/* 36 */  "SELECT max( level %% 1024 ) FROM %Q.'%q_segdir'"
  };
  int rc = SQLITE_OK;
  sqlite3_stmt *pStmt;

  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
  
................................................................................
/*
** Update the Fts3Table.mxLevel field, if appropriate
*/
static void fts3UpdateMaxLevel(Fts3Table *p, sqlite3_int64 iLevel){
  iLevel %= FTS3_SEGDIR_MAXLEVEL;
  if( iLevel>p->mxLevel ) p->mxLevel = iLevel;
}

/*
** Find the largest relative level number in the table. If successful, set
** *pnMax to this value and return SQLITE_OK. Otherwise, if an error occurs,
** set *pnMax to zero and return an SQLite error code.
*/
int sqlite3Fts3MaxLevel(Fts3Table *p, int *pnMax){
  int rc;
  int mxLevel = 0;
  sqlite3_stmt *pStmt = 0;

  rc = fts3SqlStmt(p, SQL_SELECT_MXLEVEL, &pStmt, 0);
  if( rc==SQLITE_OK ){
    if( SQLITE_ROW==sqlite3_step(pStmt) ){
      mxLevel = sqlite3_column_int(pStmt, 0);
    }
    rc = sqlite3_reset(pStmt);
  }
  *pnMax = mxLevel;
  return rc;
}

/* 
** Insert a record into the %_segdir table.
*/
static int fts3WriteSegdir(
  Fts3Table *p,                   /* Virtual table handle */
  sqlite3_int64 iLevel,           /* Value for "level" field (absolute level) */
................................................................................

  if( nData>0 && nData+nReq>p->nNodeSize ){
    int rc;

    /* The current leaf node is full. Write it out to the database. */
    rc = fts3WriteSegment(p, pWriter->iFree++, pWriter->aData, nData);
    if( rc!=SQLITE_OK ) return rc;
    p->nLeafAdd++;

    /* Add the current term to the interior node tree. The term added to
    ** the interior tree must:
    **
    **   a) be greater than the largest term on the leaf node just written
    **      to the database (still available in pWriter->zTerm), and
    **
................................................................................
          p, iLevel, iIdx, pWriter->iFirst, iLastLeaf, iLast, zRoot, nRoot);
    }
  }else{
    /* The entire tree fits on the root node. Write it to the segdir table. */
    rc = fts3WriteSegdir(
        p, iLevel, iIdx, 0, 0, 0, pWriter->aData, pWriter->nData);
  }
  p->nLeafAdd++;
  return rc;
}

/*
** Release all memory held by the SegmentWriter object passed as the 
** first argument.
*/
................................................................................
/* 
** Flush the contents of pendingTerms to level 0 segments.
*/
int sqlite3Fts3PendingTermsFlush(Fts3Table *p){
  int rc = SQLITE_OK;
  int i;
        

  for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
    rc = fts3SegmentMerge(p, p->iPrevLangid, i, FTS3_SEGCURSOR_PENDING);
    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
  }
  sqlite3Fts3PendingTermsClear(p);

  /* Determine the auto-incr-merge setting if unknown.  If enabled,