SQLite

  int nIdx;                       /* Number of entries in aIdx[] */
  int aIdx[0];                    /* Offsets into aPoslist for current row */
};


/*
** Virtual-table cursor object.
**
** zSpecial:
**   If this is a 'special' query (refer to function fts5SpecialMatch()), 
**   then this variable points to a nul-terminated buffer containing the
**   result to return through the table-name column. It is nul-terminated
**   and should eventually be freed using sqlite3_free().
*/
struct Fts5Cursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  int idxNum;                     /* idxNum passed to xFilter() */
  sqlite3_stmt *pStmt;            /* Statement used to read %_content */
  Fts5Expr *pExpr;                /* Expression for MATCH queries */
  Fts5Sorter *pSorter;            /* Sorter for "ORDER BY rank" queries */
  int csrflags;                   /* Mask of cursor flags (see below) */
  Fts5Cursor *pNext;              /* Next cursor in Fts5Cursor.pCsr list */
  Fts5Auxiliary *pRank;           /* Rank callback (or NULL) */
  char *zSpecial;                 /* Result of special query */

  /* Variables used by auxiliary functions */
  i64 iCsrId;                     /* Cursor id */
  Fts5Auxiliary *pAux;            /* Currently executing extension function */
  Fts5Auxdata *pAuxdata;          /* First in linked list of saved aux-data */
  int *aColumnSize;               /* Values for xColumnSize() */
};

** The three query plans xBestIndex may choose between.
*/
#define FTS5_PLAN_SCAN           1       /* No usable constraint */
#define FTS5_PLAN_MATCH          2       /* (<tbl> MATCH ?) */
#define FTS5_PLAN_SORTED_MATCH   3       /* (<tbl> MATCH ? ORDER BY rank) */
#define FTS5_PLAN_ROWID          4       /* (rowid = ?) */
#define FTS5_PLAN_SOURCE         5       /* A source cursor for SORTED_MATCH */
#define FTS5_PLAN_SPECIAL        6       /* An internal query */

#define FTS5_PLAN(idxNum) ((idxNum) & 0x7)

#define FTS5_ORDER_DESC   8       /* ORDER BY rowid DESC */
#define FTS5_ORDER_ASC   16       /* ORDER BY rowid ASC */

/*

    sqlite3_free(pData);
  }

  /* Remove the cursor from the Fts5Global.pCsr list */
  for(pp=&pTab->pGlobal->pCsr; (*pp)!=pCsr; pp=&(*pp)->pNext);
  *pp = pCsr->pNext;

  sqlite3_free(pCsr->zSpecial);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

static int fts5SorterNext(Fts5Cursor *pCsr){
  Fts5Sorter *pSorter = pCsr->pSorter;
  int rc;

    case FTS5_PLAN_SOURCE:
      rc = sqlite3Fts5ExprNext(pCsr->pExpr);
      if( sqlite3Fts5ExprEof(pCsr->pExpr) ){
        CsrFlagSet(pCsr, FTS5CSR_EOF);
      }
      CsrFlagSet(pCsr, FTS5CSR_REQUIRE_CONTENT | FTS5CSR_REQUIRE_DOCSIZE );
      break;

    case FTS5_PLAN_SPECIAL: {
      CsrFlagSet(pCsr, FTS5CSR_EOF);
      break;
    }

    case FTS5_PLAN_SORTED_MATCH: {
      rc = fts5SorterNext(pCsr);
      break;
    }

    default:

  rc = sqlite3Fts5ExprFirst(pCsr->pExpr, pTab->pIndex, bAsc);
  if( sqlite3Fts5ExprEof(pCsr->pExpr) ){
    CsrFlagSet(pCsr, FTS5CSR_EOF);
  }
  CsrFlagSet(pCsr, FTS5CSR_REQUIRE_CONTENT | FTS5CSR_REQUIRE_DOCSIZE );
  return rc;
}

/*
** Process a "special" query. A special query is identified as one with a
** MATCH expression that begins with a '*' character. The remainder of
** the text passed to the MATCH operator are used as  the special query
** parameters.
*/
static int fts5SpecialMatch(
  Fts5Table *pTab, 
  Fts5Cursor *pCsr, 
  const char *zQuery
){
  int rc = SQLITE_OK;             /* Return code */
  const char *z = zQuery;         /* Special query text */
  int n;                          /* Number of bytes in text at z */

  while( z[0]==' ' ) z++;
  for(n=0; z[n] && z[n]!=' '; n++);

  assert( pTab->base.zErrMsg==0 );
  assert( pCsr->zSpecial==0 );

  if( 0==sqlite3_strnicmp("reads", z, n) ){
    pCsr->zSpecial = sqlite3_mprintf("%d", sqlite3Fts5IndexReads(pTab->pIndex));
    pCsr->idxNum = FTS5_PLAN_SPECIAL;
    if( pCsr->zSpecial==0 ) rc = SQLITE_NOMEM;
  }
  else{
    /* An unrecognized directive. Return an error message. */
    pTab->base.zErrMsg = sqlite3_mprintf("unknown special query: %.*s", n, z);
    rc = SQLITE_ERROR;
  }

  return rc;
}


/*
** This is the xFilter interface for the virtual table.  See
** the virtual table xFilter method documentation for additional
** information.
*/
static int fts5FilterMethod(

  assert( pCsr->pStmt==0 );
  assert( pCsr->pExpr==0 );
  assert( pCsr->csrflags==0 );
  assert( pCsr->pRank==0 );

  if( pTab->pSortCsr ){
    /* If pSortCsr is non-NULL, then this call is being made as part of 
    ** processing for a "... MATCH <expr> ORDER BY rank" query (ePlan is
    ** set to FTS5_PLAN_SORTED_MATCH). pSortCsr is the cursor that will
    ** return results to the user for this query. The current cursor 
    ** (pCursor) is used to execute the query issued by function 
    ** fts5CursorFirstSorted() above.  */
    assert( FTS5_PLAN(idxNum)==FTS5_PLAN_SCAN );
    pCsr->idxNum = FTS5_PLAN_SOURCE;
    pCsr->pRank = pTab->pSortCsr->pRank;
    pCsr->pExpr = pTab->pSortCsr->pExpr;
    rc = fts5CursorFirst(pTab, pCsr, bAsc);
  }else{
    int ePlan = FTS5_PLAN(idxNum);

    pCsr->idxNum = idxNum;


    if( ePlan==FTS5_PLAN_MATCH || ePlan==FTS5_PLAN_SORTED_MATCH ){

      const char *zExpr = (const char*)sqlite3_value_text(apVal[0]);

      if( zExpr[0]=='*' ){
        /* The user has issued a query of the form "MATCH '*...'". This
        ** indicates that the MATCH expression is not a full text query,
        ** but a request for an internal parameter.  */
        rc = fts5SpecialMatch(pTab, pCsr, &zExpr[1]);
      }else{
        char **pzErr = &pTab->base.zErrMsg;
        pCsr->pRank = pTab->pGlobal->pAux;
        rc = sqlite3Fts5ExprNew(pTab->pConfig, zExpr, &pCsr->pExpr, pzErr);
        if( rc==SQLITE_OK ){
          if( ePlan==FTS5_PLAN_MATCH ){
            rc = fts5CursorFirst(pTab, pCsr, bAsc);
          }else{
            rc = fts5CursorFirstSorted(pTab, pCsr, bAsc);
          }
        }
      }
    }else{
      /* This is either a full-table scan (ePlan==FTS5_PLAN_SCAN) or a lookup
      ** by rowid (ePlan==FTS5_PLAN_ROWID).  */
      int eStmt = fts5StmtType(idxNum);
      rc = sqlite3Fts5StorageStmt(pTab->pStorage, eStmt, &pCsr->pStmt);
      if( rc==SQLITE_OK ){
        if( ePlan==FTS5_PLAN_ROWID ){
          sqlite3_bind_value(pCsr->pStmt, 1, apVal[0]);
        }
        rc = fts5NextMethod(pCursor);
      }
    }
  }

*/
static int fts5RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
  int ePlan = FTS5_PLAN(pCsr->idxNum);
  
  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );
  switch( ePlan ){
    case FTS5_PLAN_SPECIAL:
      *pRowid = 0;
      break;

    case FTS5_PLAN_SOURCE:
    case FTS5_PLAN_MATCH:
    case FTS5_PLAN_SORTED_MATCH:
      *pRowid = fts5CursorRowid(pCsr);
      break;

    default:
      *pRowid = sqlite3_column_int64(pCsr->pStmt, 0);
      break;
  }

  return SQLITE_OK;
}

/*
** If the cursor requires seeking (bSeekRequired flag is set), seek it.
** Return SQLITE_OK if no error occurs, or an SQLite error code otherwise.
*/
static int fts5SeekCursor(Fts5Cursor *pCsr){
  int rc = SQLITE_OK;

  /* If the cursor does not yet have a statement handle, obtain one now. */ 
  if( pCsr->pStmt==0 ){
    Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
    int eStmt = fts5StmtType(pCsr->idxNum);
    rc = sqlite3Fts5StorageStmt(pTab->pStorage, eStmt, &pCsr->pStmt);
    assert( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) );
  }

  if( rc==SQLITE_OK && CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) ){
    assert( pCsr->pExpr );
    sqlite3_reset(pCsr->pStmt);
    sqlite3_bind_int64(pCsr->pStmt, 1, fts5CursorRowid(pCsr));
    rc = sqlite3_step(pCsr->pStmt);
    if( rc==SQLITE_ROW ){
      rc = SQLITE_OK;
      CsrFlagClear(pCsr, FTS5CSR_REQUIRE_CONTENT);

  int iCol                        /* Index of column to read value from */
){
  Fts5Config *pConfig = ((Fts5Table*)(pCursor->pVtab))->pConfig;
  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
  int rc = SQLITE_OK;
  
  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );

  if( pCsr->idxNum==FTS5_PLAN_SPECIAL ){
    if( iCol==pConfig->nCol ){
      sqlite3_result_text(pCtx, pCsr->zSpecial, -1, SQLITE_TRANSIENT);
    }
  }else

  if( iCol==pConfig->nCol ){
    if( FTS5_PLAN(pCsr->idxNum)==FTS5_PLAN_SOURCE ){
      fts5PoslistBlob(pCtx, pCsr);
    }else{
      /* User is requesting the value of the special column with the same name
      ** as the table. Return the cursor integer id number. This value is only

  int flags                       /* Mask of FTS5INDEX_QUERY_X flags */
);

/*
** Docid list iteration.
*/
int  sqlite3Fts5IterEof(Fts5IndexIter*);
void sqlite3Fts5IterNext(Fts5IndexIter*);
void sqlite3Fts5IterNextFrom(Fts5IndexIter*, i64 iMatch);
i64  sqlite3Fts5IterRowid(Fts5IndexIter*);

/*
** Obtain the position list that corresponds to the current position.
*/
const u8 *sqlite3Fts5IterPoslist(Fts5IndexIter*, int *pn);

/* Called during startup to register a UDF with SQLite */
int sqlite3Fts5IndexInit(sqlite3*);

void sqlite3Fts5IndexPgsz(Fts5Index *p, int pgsz);

int sqlite3Fts5IndexGetAverages(Fts5Index *p, Fts5Buffer *pBuf);
int sqlite3Fts5IndexSetAverages(Fts5Index *p, const u8*, int);

int sqlite3Fts5IndexReads(Fts5Index *p);

/*
** End of interface to code in fts5_index.c.
**************************************************************************/

/**************************************************************************
** Interface to code in fts5_storage.c. fts5_storage.c contains contains 

  int rc = SQLITE_OK;             /* Return code */
  int i, j;                       /* Phrase and token index, respectively */

  for(i=0; i<pNear->nPhrase; i++){
    Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
    for(j=0; j<pPhrase->nTerm; j++){
      Fts5IndexIter *pIter = pPhrase->aTerm[j].pIter;
      sqlite3Fts5IterNext(pIter);
      if( sqlite3Fts5IterEof(pIter) ){
        *pbEof = 1;
        return rc;
      }
    }
  }

  int bAsc,                       /* True if iterator is "rowid ASC" */
  i64 *piLast,                    /* IN/OUT: Lastest rowid seen so far */
  int *pRc,                       /* OUT: Error code */
  int *pbEof                      /* OUT: Set to true if EOF */
){
  i64 iLast = *piLast;
  i64 iRowid;

  iRowid = sqlite3Fts5IterRowid(pIter);
  if( (bAsc==0 && iRowid>iLast) || (bAsc && iRowid<iLast) ){
    sqlite3Fts5IterNextFrom(pIter, iLast);
    if( sqlite3Fts5IterEof(pIter) ){
      *pbEof = 1;
      return 1;
    }
    iRowid = sqlite3Fts5IterRowid(pIter);
    assert( (bAsc==0 && iRowid<=iLast) || (bAsc==1 && iRowid>=iLast) );
  }


  *piLast = iRowid;


  return 0;
}

/*
** All individual term iterators in pNear are guaranteed to be valid when
** this function is called. This function checks if all term iterators

      }
    }
  }

  return SQLITE_OK;
}

/* fts5ExprNodeNext() calls fts5ExprNodeNextMatch(). And vice-versa. */
static int fts5ExprNodeNextMatch(Fts5Expr*, Fts5ExprNode*);

/*
** Compare the values currently indicated by the two nodes as follows:
**
**    res = (*p1) - (*p2)
**

  /* Error state. */
  int rc;                         /* Current error code */

  /* State used by the fts5DataXXX() functions. */
  sqlite3_blob *pReader;          /* RO incr-blob open on %_data table */
  sqlite3_stmt *pWriter;          /* "INSERT ... %_data VALUES(?,?)" */
  sqlite3_stmt *pDeleter;         /* "DELETE FROM %_data ... id>=? AND id<=?" */
  int nRead;                      /* Total number of blocks read */
};

struct Fts5DoclistIter {
  int bAsc;
  u8 *a;
  int n;
  int i;

        if( rc!=SQLITE_OK ){
          sqlite3_free(pRet);
          pRet = 0;
        }
      }
    }
    p->rc = rc;
    p->nRead++;
  }

  return pRet;
}

/*
** Retrieve a record from the %_data table.

/*
** Return the rowid of the entry that the iterator currently points
** to. If the iterator points to EOF when this function is called the
** results are undefined.
*/
static i64 fts5MultiIterRowid(Fts5MultiSegIter *pIter){
  assert( pIter->aSeg[ pIter->aFirst[1] ].pLeaf );
  return pIter->aSeg[ pIter->aFirst[1] ].iRowid;
}

/*
** Move the iterator to the next entry at or following iMatch.
*/
static void fts5MultiIterNextFrom(
  Fts5Index *p, 
  Fts5MultiSegIter *pIter, 
  i64 iMatch
){
  while( 1 ){
    i64 iRowid;
    fts5MultiIterNext(p, pIter);
    if( fts5MultiIterEof(p, pIter) ) break;
    iRowid = fts5MultiIterRowid(pIter);
    if( pIter->bRev==0 && iRowid<=iMatch ) break;
    if( pIter->bRev!=0 && iRowid>=iMatch ) break;
  }
}

/*
** Return a pointer to a buffer containing the term associated with the 
** entry that the iterator currently points to.
*/
static const u8 *fts5MultiIterTerm(Fts5MultiSegIter *pIter, int *pn){
  Fts5SegIter *p = &pIter->aSeg[ pIter->aFirst[1] ];

    return fts5MultiIterEof(pIter->pIndex, pIter->pMulti);
  }
}

/*
** Move to the next matching rowid. 
*/
void sqlite3Fts5IterNext(Fts5IndexIter *pIter){
  if( pIter->pDoclist ){
    fts5DoclistIterNext(pIter->pDoclist);
  }else{
    fts5BufferZero(&pIter->poslist);
    fts5MultiIterNext(pIter->pIndex, pIter->pMulti);
  }
}

/*
** Move to the next matching rowid that occurs at or after iMatch. The
** definition of "at or after" depends on whether this iterator iterates
** in ascending or descending rowid order.
*/
void sqlite3Fts5IterNextFrom(Fts5IndexIter *pIter, i64 iMatch){
  if( pIter->pDoclist ){
    assert( 0 );
    /* fts5DoclistIterNextFrom(pIter->pDoclist, iMatch); */
  }else{
    fts5MultiIterNextFrom(pIter->pIndex, pIter->pMulti, iMatch);
  }
}

/*
** Return the current rowid.
*/
i64 sqlite3Fts5IterRowid(Fts5IndexIter *pIter){
  if( pIter->pDoclist ){
    return pIter->pDoclist->iRowid;

** Replace the current "averages" record with the contents of the buffer 
** supplied as the second argument.
*/
int sqlite3Fts5IndexSetAverages(Fts5Index *p, const u8 *pData, int nData){
  fts5DataWrite(p, FTS5_AVERAGES_ROWID, pData, nData);
  return p->rc;
}

/*
** Return the total number of blocks this module has read from the %_data
** table since it was created.
*/
int sqlite3Fts5IndexReads(Fts5Index *p){
  return p->nRead;
}

#
do_catchsql_test 11.1 {
  CREATE VIRTUAL TABLE t2 USING fts5(a, b, c, rank);
} {1 {reserved fts5 column name: rank}}
do_catchsql_test 11.2 {
  CREATE VIRTUAL TABLE rank USING fts5(a, b, c);
} {1 {reserved fts5 table name: rank}}

#-------------------------------------------------------------------------
#
do_execsql_test 12.1 {
  CREATE VIRTUAL TABLE t2 USING fts5(x,y);
} {}

do_catchsql_test 12.2 {
  SELECT t2 FROM t2 WHERE t2 MATCH '*stuff'
} {1 {unknown special query: stuff}}

do_test 12.3 {
  set res [db one { SELECT t2 FROM t2 WHERE t2 MATCH '* reads ' }]
  string is integer $res
} {1}

finish_test

  SELECT rowid FROM t1 WHERE t1 MATCH 'y AND x'
} [lsort -integer -decr $Y]

do_execsql_test 1.3 {
  INSERT INTO t1(t1) VALUES('integrity-check');
}

proc reads {} {
  db one {SELECT t1 FROM t1 WHERE t1 MATCH '*reads'}
}

do_test 1.4 {
  set nRead [reads]
  db eval { SELECT rowid FROM t1 WHERE t1 MATCH 'x' }
  set a [expr [reads] - $nRead]
} {}

do_test 1.5 {
  set nRead [reads]
  db eval { SELECT rowid FROM t1 WHERE t1 MATCH 'x + w' }
  set a [expr [reads] - $nRead]
} {}


finish_test