char *zContentCols;             /* Columns of %_content table */
  char *zSql;                     /* SQL script to create required tables */

  /* Create a list of user columns for the content table */
  zContentCols = sqlite3_mprintf("docid INTEGER PRIMARY KEY");
  for(i=0; zContentCols && i<p->nColumn; i++){
    char *z = p->azColumn[i];
    zContentCols = sqlite3_mprintf("%z, 'c%d%q'", zContentCols, i+1, z);
  }

  /* Create the whole SQL script */
  zSql = sqlite3_mprintf(
      "CREATE TABLE %Q.'%q_content'(%s);"
      "CREATE TABLE %Q.'%q_segments'(blockid INTEGER PRIMARY KEY, block BLOB);"
      "CREATE TABLE %Q.'%q_segdir'("
................................................................................
    sqlite3_int64 iChild;         /* Block id of child node to descend to */
    int nBlock;                   /* Size of child node in bytes */

    zCsr += sqlite3Fts3GetVarint32(zCsr, &iHeight);
    zCsr += sqlite3Fts3GetVarint(zCsr, &iChild);
  
    while( zCsr<zEnd ){

      int nSuffix;                /* Size of term suffix */
      int nPrefix = 0;            /* Size of term prefix */
      int nBuffer;                /* Total term size */
      int nMin;                   /* Minimum of nBuffer and nTerm */
  
      /* Load the next term on the node into zBuffer */
      if( zBuffer ){
        zCsr += sqlite3Fts3GetVarint32(zCsr, &nPrefix);
      }
      zCsr += sqlite3Fts3GetVarint32(zCsr, &nSuffix);
      if( nPrefix+nSuffix>nAlloc ){
................................................................................
      ** to the term from the interior node, then all terms on the sub-tree 
      ** headed by node iChild are smaller than zTerm. No need to search 
      ** iChild.
      **
      ** If the interior node term is larger than the specified term, then
      ** the tree headed by iChild may contain the specified term.
      */
      nMin = (nBuffer>nTerm ? nTerm : nBuffer);
      if( memcmp(zTerm, zBuffer, nMin)<0 ) break;
      iChild++;
    };

    /* If (iHeight==1), the children of this interior node are leaves. The
    ** specified term may be present on leaf node iChild.
    */
    if( iHeight==1 ){
................................................................................
  char *zTerm,
  int nTerm,
  char *aDoclist,
  int nDoclist
){
  TermSelect *pTS = (TermSelect *)pContext;
  int nNew = pTS->nOutput + nDoclist;

  char *aNew = sqlite3_malloc(nNew);

  if( !aNew ){
    return SQLITE_NOMEM;
  }

  if( pTS->nOutput==0 ){
    /* If this is the first term selected, copy the doclist to the output
    ** buffer using memcpy(). TODO: Add a way to transfer control of the
................................................................................
      ** create a Fts3SegReader to scan the single leaf. 
      */
      rc = sqlite3Fts3SegReaderNew(p, iAge, 0, 0, 0, zRoot, nRoot, &pNew);
    }else{
      sqlite3_int64 i1;
      rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &i1);
      if( rc==SQLITE_OK ){
        sqlite3_int64 i2 = sqlite3_column_int64(pStmt, 3);
        rc = sqlite3Fts3SegReaderNew(p, iAge, i1, i2, 0, 0, 0, &pNew);
      }
    }
    iAge++;

    /* If a new Fts3SegReader was allocated, add it to the apSegment array. */
    assert( (rc==SQLITE_OK)==(pNew!=0) );
................................................................................
  filter.flags = FTS3_SEGMENT_IGNORE_EMPTY 
        | (isPrefix ? FTS3_SEGMENT_PREFIX : 0)
        | (isReqPos ? FTS3_SEGMENT_REQUIRE_POS : 0)
        | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0);
  filter.iCol = iColumn;
  filter.zTerm = zTerm;
  filter.nTerm = nTerm;

  rc = sqlite3Fts3SegReaderIterate(p, apSegment, nSegment, &filter,
      fts3TermSelectCb, (void *)&tsc
  );

  if( rc==SQLITE_OK ){
    *ppOut = tsc.aOutput;
    *pnOut = tsc.nOutput;

  char *zContentCols;             /* Columns of %_content table */
  char *zSql;                     /* SQL script to create required tables */

  /* Create a list of user columns for the content table */
  zContentCols = sqlite3_mprintf("docid INTEGER PRIMARY KEY");
  for(i=0; zContentCols && i<p->nColumn; i++){
    char *z = p->azColumn[i];
    zContentCols = sqlite3_mprintf("%z, 'c%d%q'", zContentCols, i, z);
  }

  /* Create the whole SQL script */
  zSql = sqlite3_mprintf(
      "CREATE TABLE %Q.'%q_content'(%s);"
      "CREATE TABLE %Q.'%q_segments'(blockid INTEGER PRIMARY KEY, block BLOB);"
      "CREATE TABLE %Q.'%q_segdir'("
................................................................................
    sqlite3_int64 iChild;         /* Block id of child node to descend to */
    int nBlock;                   /* Size of child node in bytes */

    zCsr += sqlite3Fts3GetVarint32(zCsr, &iHeight);
    zCsr += sqlite3Fts3GetVarint(zCsr, &iChild);
  
    while( zCsr<zEnd ){
      int cmp;                    /* memcmp() result */
      int nSuffix;                /* Size of term suffix */
      int nPrefix = 0;            /* Size of term prefix */
      int nBuffer;                /* Total term size */

  
      /* Load the next term on the node into zBuffer */
      if( zBuffer ){
        zCsr += sqlite3Fts3GetVarint32(zCsr, &nPrefix);
      }
      zCsr += sqlite3Fts3GetVarint32(zCsr, &nSuffix);
      if( nPrefix+nSuffix>nAlloc ){
................................................................................
      ** to the term from the interior node, then all terms on the sub-tree 
      ** headed by node iChild are smaller than zTerm. No need to search 
      ** iChild.
      **
      ** If the interior node term is larger than the specified term, then
      ** the tree headed by iChild may contain the specified term.
      */
      cmp = memcmp(zTerm, zBuffer, (nBuffer>nTerm ? nTerm : nBuffer));
      if( cmp<0 || (cmp==0 && nBuffer>nTerm) ) break;
      iChild++;
    };

    /* If (iHeight==1), the children of this interior node are leaves. The
    ** specified term may be present on leaf node iChild.
    */
    if( iHeight==1 ){
................................................................................
  char *zTerm,
  int nTerm,
  char *aDoclist,
  int nDoclist
){
  TermSelect *pTS = (TermSelect *)pContext;
  int nNew = pTS->nOutput + nDoclist;

  char *aNew = sqlite3_malloc(nNew);

  if( !aNew ){
    return SQLITE_NOMEM;
  }

  if( pTS->nOutput==0 ){
    /* If this is the first term selected, copy the doclist to the output
    ** buffer using memcpy(). TODO: Add a way to transfer control of the
................................................................................
      ** create a Fts3SegReader to scan the single leaf. 
      */
      rc = sqlite3Fts3SegReaderNew(p, iAge, 0, 0, 0, zRoot, nRoot, &pNew);
    }else{
      sqlite3_int64 i1;
      rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &i1);
      if( rc==SQLITE_OK ){
        sqlite3_int64 i2 = sqlite3_column_int64(pStmt, 2);
        rc = sqlite3Fts3SegReaderNew(p, iAge, i1, i2, 0, 0, 0, &pNew);
      }
    }
    iAge++;

    /* If a new Fts3SegReader was allocated, add it to the apSegment array. */
    assert( (rc==SQLITE_OK)==(pNew!=0) );
................................................................................
  filter.flags = FTS3_SEGMENT_IGNORE_EMPTY 
        | (isPrefix ? FTS3_SEGMENT_PREFIX : 0)
        | (isReqPos ? FTS3_SEGMENT_REQUIRE_POS : 0)
        | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0);
  filter.iCol = iColumn;
  filter.zTerm = zTerm;
  filter.nTerm = nTerm;

  rc = sqlite3Fts3SegReaderIterate(p, apSegment, nSegment, &filter,
      fts3TermSelectCb, (void *)&tsc
  );

  if( rc==SQLITE_OK ){
    *ppOut = tsc.aOutput;
    *pnOut = tsc.nOutput;

static int fts3SqlStmt(
  Fts3Table *p, 
  int eStmt, 
  sqlite3_stmt **pp, 
  sqlite3_value **apVal
){
  const char *azSql[] = {
    "DELETE FROM %Q.'%q_content' WHERE rowid = ?",
    "SELECT NOT EXISTS(SELECT docid FROM %Q.'%q_content' WHERE rowid!=?)",
    "DELETE FROM %Q.'%q_content'",
    "DELETE FROM %Q.'%q_segments'",
    "DELETE FROM %Q.'%q_segdir'",
    "SELECT * FROM %Q.'%q_content' WHERE rowid=?",
    "SELECT coalesce(max(idx)+1, 0) FROM %Q.'%q_segdir' WHERE level=?",
    "INSERT INTO %Q.'%q_segments'(blockid, block) VALUES(?, ?)",
    "SELECT coalesce(max(blockid)+1, 1) FROM %Q.'%q_segments'",
    "INSERT INTO %Q.'%q_segdir' VALUES(?,?,?,?,?,?)",

    /* Return segments in order from oldest to newest.*/ 
    "SELECT idx, start_block, leaves_end_block, end_block, root "
        "FROM %Q.'%q_segdir' WHERE level = ? ORDER BY idx ASC",
    "SELECT idx, start_block, leaves_end_block, end_block, root "
        "FROM %Q.'%q_segdir' ORDER BY level DESC, idx ASC",

    "SELECT count(*) FROM %Q.'%q_segdir' WHERE level = ?",
    "SELECT count(*), max(level) FROM %Q.'%q_segdir'",

    "DELETE FROM %Q.'%q_segdir' WHERE level = ?",
    "DELETE FROM %Q.'%q_segments' WHERE blockid BETWEEN ? AND ?",
    0, /* CONTENT_INSERT - generated elsewhere */
    "SELECT block FROM %Q.'%q_segments' WHERE blockid = ?",

  };
  int rc = SQLITE_OK;
  sqlite3_stmt *pStmt;

  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
  
................................................................................
** Set *ppStmt to a statement handle that may be used to iterate through
** all rows in the %_segdir table, from oldest to newest. If successful,
** return SQLITE_OK. If an error occurs while preparing the statement, 
** return an SQLite error code.
**
** There is only ever one instance of this SQL statement compiled for
** each FTS3 table.








*/
int sqlite3Fts3AllSegdirs(Fts3Table *p, sqlite3_stmt **ppStmt){
  return fts3SqlStmt(p, SQL_SELECT_ALL_LEVEL, ppStmt, 0);
}


static int fts3SqlExec(Fts3Table *p, int eStmt, sqlite3_value **apVal){
................................................................................
    pReader->zTerm = zNew;
    pReader->nTermAlloc = nNew;
  }
  memcpy(&pReader->zTerm[nPrefix], pNext, nSuffix);
  pReader->nTerm = nPrefix+nSuffix;
  pNext += nSuffix;
  pNext += sqlite3Fts3GetVarint32(pNext, &pReader->nDoclist);

  pReader->aDoclist = pNext;
  pReader->pOffsetList = 0;
  return SQLITE_OK;
}

static void fts3SegReaderFirstDocid(Fts3SegReader *pReader){
  int n;
................................................................................
  }

  /* If there are no more entries in the doclist, set pOffsetList to
  ** NULL. Otherwise, set Fts3SegReader.iDocid to the next docid and
  ** Fts3SegReader.pOffsetList to point to the next offset list before
  ** returning.
  */
  if( p==&pReader->aDoclist[pReader->nDoclist] ){
    pReader->pOffsetList = 0;
  }else{
    sqlite3_int64 iDelta;
    pReader->pOffsetList = p + sqlite3Fts3GetVarint(p, &iDelta);
    pReader->iDocid += iDelta;
  }
}

static int fts3SqlStmt(
  Fts3Table *p, 
  int eStmt, 
  sqlite3_stmt **pp, 
  sqlite3_value **apVal
){
  const char *azSql[] = {
/* 0  */  "DELETE FROM %Q.'%q_content' WHERE rowid = ?",
/* 1  */  "SELECT NOT EXISTS(SELECT docid FROM %Q.'%q_content' WHERE rowid!=?)",
/* 2  */  "DELETE FROM %Q.'%q_content'",
/* 3  */  "DELETE FROM %Q.'%q_segments'",
/* 4  */  "DELETE FROM %Q.'%q_segdir'",
/* 5  */  "SELECT * FROM %Q.'%q_content' WHERE rowid=?",
/* 6  */  "SELECT coalesce(max(idx)+1, 0) FROM %Q.'%q_segdir' WHERE level=?",
/* 7  */  "INSERT INTO %Q.'%q_segments'(blockid, block) VALUES(?, ?)",
/* 8  */  "SELECT coalesce(max(blockid)+1, 1) FROM %Q.'%q_segments'",
/* 9  */  "INSERT INTO %Q.'%q_segdir' VALUES(?,?,?,?,?,?)",

          /* Return segments in order from oldest to newest.*/ 
/* 10 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
            "FROM %Q.'%q_segdir' WHERE level = ? ORDER BY idx ASC",
/* 11 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
            "FROM %Q.'%q_segdir' ORDER BY level DESC, idx ASC",

/* 12 */  "SELECT count(*) FROM %Q.'%q_segdir' WHERE level = ?",
/* 13 */  "SELECT count(*), max(level) FROM %Q.'%q_segdir'",

/* 14 */  "DELETE FROM %Q.'%q_segdir' WHERE level = ?",
/* 15 */  "DELETE FROM %Q.'%q_segments' WHERE blockid BETWEEN ? AND ?",
/* 16 */  0, /* CONTENT_INSERT - generated elsewhere */
/* 17 */  "SELECT block FROM %Q.'%q_segments' WHERE blockid = ?",

  };
  int rc = SQLITE_OK;
  sqlite3_stmt *pStmt;

  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
  
................................................................................
** Set *ppStmt to a statement handle that may be used to iterate through
** all rows in the %_segdir table, from oldest to newest. If successful,
** return SQLITE_OK. If an error occurs while preparing the statement, 
** return an SQLite error code.
**
** There is only ever one instance of this SQL statement compiled for
** each FTS3 table.
**
** The statement returns the following columns from the %_segdir table:
**
**   0: idx
**   1: start_block
**   2: leaves_end_block
**   3: end_block
**   4: root
*/
int sqlite3Fts3AllSegdirs(Fts3Table *p, sqlite3_stmt **ppStmt){
  return fts3SqlStmt(p, SQL_SELECT_ALL_LEVEL, ppStmt, 0);
}


static int fts3SqlExec(Fts3Table *p, int eStmt, sqlite3_value **apVal){
................................................................................
    pReader->zTerm = zNew;
    pReader->nTermAlloc = nNew;
  }
  memcpy(&pReader->zTerm[nPrefix], pNext, nSuffix);
  pReader->nTerm = nPrefix+nSuffix;
  pNext += nSuffix;
  pNext += sqlite3Fts3GetVarint32(pNext, &pReader->nDoclist);
  assert( pNext<&pReader->aNode[pReader->nNode] );
  pReader->aDoclist = pNext;
  pReader->pOffsetList = 0;
  return SQLITE_OK;
}

static void fts3SegReaderFirstDocid(Fts3SegReader *pReader){
  int n;
................................................................................
  }

  /* If there are no more entries in the doclist, set pOffsetList to
  ** NULL. Otherwise, set Fts3SegReader.iDocid to the next docid and
  ** Fts3SegReader.pOffsetList to point to the next offset list before
  ** returning.
  */
  if( p>=&pReader->aDoclist[pReader->nDoclist] ){
    pReader->pOffsetList = 0;
  }else{
    sqlite3_int64 iDelta;
    pReader->pOffsetList = p + sqlite3Fts3GetVarint(p, &iDelta);
    pReader->iDocid += iDelta;
  }
}