/*
** Retrieve and clear the current error code, respectively.
*/
int sqlite3Fts5IndexErrcode(Fts5Index*);
void sqlite3Fts5IndexReset(Fts5Index*);

/*
** Get or set the "averages" record.
*/
int sqlite3Fts5IndexGetAverages(Fts5Index *p, Fts5Buffer *pBuf);
int sqlite3Fts5IndexSetAverages(Fts5Index *p, const u8*, int);

/*
** Functions called by the storage module as part of integrity-check.
*/
u64 sqlite3Fts5IndexCksum(Fts5Config*,i64,int,int,const char*,int);
int sqlite3Fts5IndexIntegrityCheck(Fts5Index*, u64 cksum);

/*
** Retrieve and clear the current error code, respectively.
*/
int sqlite3Fts5IndexErrcode(Fts5Index*);
void sqlite3Fts5IndexReset(Fts5Index*);

/*
** Get or set the "averages" values.
*/
int sqlite3Fts5IndexGetAverages(Fts5Index *p, i64 *pnRow, i64 *anSize);
int sqlite3Fts5IndexSetAverages(Fts5Index *p, const u8*, int);

/*
** Functions called by the storage module as part of integrity-check.
*/
u64 sqlite3Fts5IndexCksum(Fts5Config*,i64,int,int,const char*,int);
int sqlite3Fts5IndexIntegrityCheck(Fts5Index*, u64 cksum);

};
struct Fts5DlidxIter {
  int nLvl;
  int iSegid;
  Fts5DlidxLvl aLvl[1];
};



/*
** The first argument passed to this macro is a pointer to an Fts5Buffer
** object.
*/
#define fts5BufferSize(pBuf,n) {                \
  if( pBuf->nSpace<n ) {                        \
    u8 *pNew = sqlite3_realloc(pBuf->p, n);     \
    if( pNew==0 ){                              \
      sqlite3_free(pBuf->p);                    \
    }                                           \
    pBuf->nSpace = n;                           \
    pBuf->p = pNew;                             \
  }                                             \
}

static void fts5PutU16(u8 *aOut, u16 iVal){
  aOut[0] = (iVal>>8);
  aOut[1] = (iVal&0xFF);
}

static u16 fts5GetU16(const u8 *aIn){
  return ((u16)aIn[0] << 8) + aIn[1];
................................................................................
  if( p->pReader ){
    sqlite3_blob *pReader = p->pReader;
    p->pReader = 0;
    sqlite3_blob_close(pReader);
  }
}

static Fts5Data *fts5DataReadOrBuffer(
  Fts5Index *p, 
  Fts5Buffer *pBuf, 
  i64 iRowid
){



  Fts5Data *pRet = 0;
  if( p->rc==SQLITE_OK ){
    int rc = SQLITE_OK;

    if( p->pReader ){
      /* This call may return SQLITE_ABORT if there has been a savepoint
      ** rollback since it was last used. In this case a new blob handle
................................................................................
      p->pReader = pBlob;
      if( rc!=SQLITE_OK ){
        fts5CloseReader(p);
      }
      if( rc==SQLITE_ABORT ) rc = SQLITE_OK;
    }

    /* If the blob handle is not yet open, open and seek it. Otherwise, use
    ** the blob_reopen() API to reseek the existing blob handle.  */
    if( p->pReader==0 && rc==SQLITE_OK ){
      Fts5Config *pConfig = p->pConfig;
      rc = sqlite3_blob_open(pConfig->db, 
          pConfig->zDb, p->zDataTbl, "block", iRowid, 0, &p->pReader
      );
    }

................................................................................
    ** table, missing row, non-blob/text in block column - indicate 
    ** backing store corruption.  */
    if( rc==SQLITE_ERROR ) rc = FTS5_CORRUPT;

    if( rc==SQLITE_OK ){
      u8 *aOut = 0;               /* Read blob data into this buffer */
      int nByte = sqlite3_blob_bytes(p->pReader);
      if( pBuf ){
        fts5BufferSize(pBuf, MAX(nByte, p->pConfig->pgsz) + 20);
        pBuf->n = nByte;
        aOut = pBuf->p;
        if( aOut==0 ){
          rc = SQLITE_NOMEM;
        }
      }else{
        int nSpace = nByte + FTS5_DATA_PADDING;
        pRet = (Fts5Data*)sqlite3_malloc(nSpace+sizeof(Fts5Data));
        if( pRet ){
          pRet->n = nByte;
          aOut = pRet->p = (u8*)&pRet[1];
        }else{
          rc = SQLITE_NOMEM;
        }
      }

      if( rc==SQLITE_OK ){
        rc = sqlite3_blob_read(p->pReader, aOut, nByte, 0);
      }
      if( rc!=SQLITE_OK ){
        sqlite3_free(pRet);
................................................................................
        pRet = 0;
      }
    }
    p->rc = rc;
    p->nRead++;
  }

  return pRet;
}

/*
** Retrieve a record from the %_data table.
**
** If an error occurs, NULL is returned and an error left in the 
** Fts5Index object.
*/
static Fts5Data *fts5DataRead(Fts5Index *p, i64 iRowid){
  Fts5Data *pRet = fts5DataReadOrBuffer(p, 0, iRowid);
  assert( (pRet==0)==(p->rc!=SQLITE_OK) );
  return pRet;
}

/*
** Read a record from the %_data table into the buffer supplied as the
** second argument.
**
** If an error occurs, an error is left in the Fts5Index object. If an
** error has already occurred when this function is called, it is a 
** no-op.
*/
static void fts5DataBuffer(Fts5Index *p, Fts5Buffer *pBuf, i64 iRowid){
  (void)fts5DataReadOrBuffer(p, pBuf, iRowid);
}

/*
** Release a reference to data record returned by an earlier call to
** fts5DataRead().
*/
static void fts5DataRelease(Fts5Data *pData){
  sqlite3_free(pData);
}
................................................................................
** Fts5Index handle. If an error has already occurred when this function
** is called, it is a no-op.
*/
static Fts5Structure *fts5StructureRead(Fts5Index *p){
  Fts5Config *pConfig = p->pConfig;
  Fts5Structure *pRet = 0;        /* Object to return */
  int iCookie;                    /* Configuration cookie */

  Fts5Buffer buf = {0, 0, 0};

  fts5DataBuffer(p, &buf, FTS5_STRUCTURE_ROWID);
  if( buf.p==0 ) return 0;
  assert( buf.nSpace>=(buf.n + FTS5_DATA_ZERO_PADDING) );
  memset(&buf.p[buf.n], 0, FTS5_DATA_ZERO_PADDING);
  p->rc = fts5StructureDecode(buf.p, buf.n, &iCookie, &pRet);

  if( p->rc==SQLITE_OK && pConfig->iCookie!=iCookie ){
    p->rc = sqlite3Fts5ConfigLoad(pConfig, iCookie);
  }

  fts5BufferFree(&buf);
  if( p->rc!=SQLITE_OK ){
    fts5StructureRelease(pRet);
    pRet = 0;
  }
  return pRet;
}

................................................................................
    if( iLeafPgno<pIter->iLeafPgno ){
      pIter->iLeafPgno = iLeafPgno+1;
      fts5SegIterReverseNewPage(p, pIter);
      bMove = 0;
    }
  }

  while( p->rc==SQLITE_OK ){
    if( bMove ) fts5SegIterNext(p, pIter, 0);
    if( pIter->pLeaf==0 ) break;
    if( bRev==0 && pIter->iRowid>=iMatch ) break;
    if( bRev!=0 && pIter->iRowid<=iMatch ) break;
    bMove = 1;
  }
}


/*
** Free the iterator object passed as the second argument.
*/
static void fts5MultiIterFree(Fts5Index *p, Fts5IndexIter *pIter){
................................................................................
/*
** The %_data table is completely empty when this function is called. This
** function populates it with the initial structure objects for each index,
** and the initial version of the "averages" record (a zero-byte blob).
*/
int sqlite3Fts5IndexReinit(Fts5Index *p){
  Fts5Structure s;

  assert( p->rc==SQLITE_OK );
  p->rc = sqlite3Fts5IndexSetAverages(p, (const u8*)"", 0);

  memset(&s, 0, sizeof(Fts5Structure));

  fts5StructureWrite(p, &s);

  return fts5IndexReturn(p);
}

/*
** Open a new Fts5Index handle. If the bCreate argument is true, create
** and initialize the underlying %_data table.
**
................................................................................
    Fts5Index *pIndex = pIter->pIndex;
    fts5MultiIterFree(pIter->pIndex, pIter);
    fts5CloseReader(pIndex);
  }
}

/*
** Read the "averages" record into the buffer supplied as the second 
** argument. Return SQLITE_OK if successful, or an SQLite error code
** if an error occurs.

*/
int sqlite3Fts5IndexGetAverages(Fts5Index *p, Fts5Buffer *pBuf){






  assert( p->rc==SQLITE_OK );
  fts5DataReadOrBuffer(p, pBuf, FTS5_AVERAGES_ROWID);









  return fts5IndexReturn(p);
}

/*
** Replace the current "averages" record with the contents of the buffer 
** supplied as the second argument.
*/

};
struct Fts5DlidxIter {
  int nLvl;
  int iSegid;
  Fts5DlidxLvl aLvl[1];
};


















static void fts5PutU16(u8 *aOut, u16 iVal){
  aOut[0] = (iVal>>8);
  aOut[1] = (iVal&0xFF);
}

static u16 fts5GetU16(const u8 *aIn){
  return ((u16)aIn[0] << 8) + aIn[1];
................................................................................
  if( p->pReader ){
    sqlite3_blob *pReader = p->pReader;
    p->pReader = 0;
    sqlite3_blob_close(pReader);
  }
}


/*
** Retrieve a record from the %_data table.
**
** If an error occurs, NULL is returned and an error left in the 
** Fts5Index object.
*/
static Fts5Data *fts5DataRead(Fts5Index *p, i64 iRowid){
  Fts5Data *pRet = 0;
  if( p->rc==SQLITE_OK ){
    int rc = SQLITE_OK;

    if( p->pReader ){
      /* This call may return SQLITE_ABORT if there has been a savepoint
      ** rollback since it was last used. In this case a new blob handle
................................................................................
      p->pReader = pBlob;
      if( rc!=SQLITE_OK ){
        fts5CloseReader(p);
      }
      if( rc==SQLITE_ABORT ) rc = SQLITE_OK;
    }

    /* If the blob handle is not open at this point, open it and seek 
    ** to the requested entry.  */
    if( p->pReader==0 && rc==SQLITE_OK ){
      Fts5Config *pConfig = p->pConfig;
      rc = sqlite3_blob_open(pConfig->db, 
          pConfig->zDb, p->zDataTbl, "block", iRowid, 0, &p->pReader
      );
    }

................................................................................
    ** table, missing row, non-blob/text in block column - indicate 
    ** backing store corruption.  */
    if( rc==SQLITE_ERROR ) rc = FTS5_CORRUPT;

    if( rc==SQLITE_OK ){
      u8 *aOut = 0;               /* Read blob data into this buffer */
      int nByte = sqlite3_blob_bytes(p->pReader);








      int nAlloc = sizeof(Fts5Data) + nByte + FTS5_DATA_PADDING;
      pRet = (Fts5Data*)sqlite3_malloc(nAlloc);
      if( pRet ){
        pRet->n = nByte;
        aOut = pRet->p = (u8*)&pRet[1];
      }else{
        rc = SQLITE_NOMEM;

      }

      if( rc==SQLITE_OK ){
        rc = sqlite3_blob_read(p->pReader, aOut, nByte, 0);
      }
      if( rc!=SQLITE_OK ){
        sqlite3_free(pRet);
................................................................................
        pRet = 0;
      }
    }
    p->rc = rc;
    p->nRead++;
  }












  assert( (pRet==0)==(p->rc!=SQLITE_OK) );
  return pRet;
}













/*
** Release a reference to data record returned by an earlier call to
** fts5DataRead().
*/
static void fts5DataRelease(Fts5Data *pData){
  sqlite3_free(pData);
}
................................................................................
** Fts5Index handle. If an error has already occurred when this function
** is called, it is a no-op.
*/
static Fts5Structure *fts5StructureRead(Fts5Index *p){
  Fts5Config *pConfig = p->pConfig;
  Fts5Structure *pRet = 0;        /* Object to return */
  int iCookie;                    /* Configuration cookie */
  Fts5Data *pData;
  Fts5Buffer buf = {0, 0, 0};

  pData = fts5DataRead(p, FTS5_STRUCTURE_ROWID);
  if( p->rc ) return 0;

  memset(&pData->p[pData->n], 0, FTS5_DATA_PADDING);
  p->rc = fts5StructureDecode(pData->p, pData->n, &iCookie, &pRet);

  if( p->rc==SQLITE_OK && pConfig->iCookie!=iCookie ){
    p->rc = sqlite3Fts5ConfigLoad(pConfig, iCookie);
  }

  fts5DataRelease(pData);
  if( p->rc!=SQLITE_OK ){
    fts5StructureRelease(pRet);
    pRet = 0;
  }
  return pRet;
}

................................................................................
    if( iLeafPgno<pIter->iLeafPgno ){
      pIter->iLeafPgno = iLeafPgno+1;
      fts5SegIterReverseNewPage(p, pIter);
      bMove = 0;
    }
  }

  do{
    if( bMove ) fts5SegIterNext(p, pIter, 0);
    if( pIter->pLeaf==0 ) break;
    if( bRev==0 && pIter->iRowid>=iMatch ) break;
    if( bRev!=0 && pIter->iRowid<=iMatch ) break;
    bMove = 1;
  }while( p->rc==SQLITE_OK );
}


/*
** Free the iterator object passed as the second argument.
*/
static void fts5MultiIterFree(Fts5Index *p, Fts5IndexIter *pIter){
................................................................................
/*
** The %_data table is completely empty when this function is called. This
** function populates it with the initial structure objects for each index,
** and the initial version of the "averages" record (a zero-byte blob).
*/
int sqlite3Fts5IndexReinit(Fts5Index *p){
  Fts5Structure s;




  memset(&s, 0, sizeof(Fts5Structure));
  fts5DataWrite(p, FTS5_AVERAGES_ROWID, (const u8*)"", 0);
  fts5StructureWrite(p, &s);

  return fts5IndexReturn(p);
}

/*
** Open a new Fts5Index handle. If the bCreate argument is true, create
** and initialize the underlying %_data table.
**
................................................................................
    Fts5Index *pIndex = pIter->pIndex;
    fts5MultiIterFree(pIter->pIndex, pIter);
    fts5CloseReader(pIndex);
  }
}

/*
** Read and decode the "averages" record from the database. 
**
** Parameter anSize must point to an array of size nCol, where nCol is
** the number of user defined columns in the FTS table.
*/
int sqlite3Fts5IndexGetAverages(Fts5Index *p, i64 *pnRow, i64 *anSize){
  int nCol = p->pConfig->nCol;
  Fts5Data *pData;

  *pnRow = 0;
  memset(anSize, 0, sizeof(i64) * nCol);
  pData = fts5DataRead(p, FTS5_AVERAGES_ROWID);
  if( p->rc==SQLITE_OK && pData->n ){

    int i = 0;
    int iCol;
    i += fts5GetVarint(&pData->p[i], (u64*)pnRow);
    for(iCol=0; i<pData->n && iCol<nCol; iCol++){
      i += fts5GetVarint(&pData->p[i], (u64*)&anSize[iCol]);
    }
  }

  fts5DataRelease(pData);
  return fts5IndexReturn(p);
}

/*
** Replace the current "averages" record with the contents of the buffer 
** supplied as the second argument.
*/

**
** Return SQLITE_OK if successful, or an SQLite error code if an error
** occurs.
*/
static int fts5StorageLoadTotals(Fts5Storage *p, int bCache){
  int rc = SQLITE_OK;
  if( p->bTotalsValid==0 ){
    int nCol = p->pConfig->nCol;
    Fts5Buffer buf;
    memset(&buf, 0, sizeof(buf));

    memset(p->aTotalSize, 0, sizeof(i64) * nCol);
    p->nTotalRow = 0;
    rc = sqlite3Fts5IndexGetAverages(p->pIndex, &buf);
    if( rc==SQLITE_OK && buf.n ){
      int i = 0;
      int iCol;
      i += fts5GetVarint(&buf.p[i], (u64*)&p->nTotalRow);
      for(iCol=0; i<buf.n && iCol<nCol; iCol++){
        i += fts5GetVarint(&buf.p[i], (u64*)&p->aTotalSize[iCol]);
      }
    }
    sqlite3_free(buf.p);
    p->bTotalsValid = bCache;
  }
  return rc;
}

/*
** Store the current contents of the p->nTotalRow and p->aTotalSize[] 

**
** Return SQLITE_OK if successful, or an SQLite error code if an error
** occurs.
*/
static int fts5StorageLoadTotals(Fts5Storage *p, int bCache){
  int rc = SQLITE_OK;
  if( p->bTotalsValid==0 ){






    rc = sqlite3Fts5IndexGetAverages(p->pIndex, &p->nTotalRow, p->aTotalSize);









    p->bTotalsValid = bCache;
  }
  return rc;
}

/*
** Store the current contents of the p->nTotalRow and p->aTotalSize[]