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 */
  char *zSpecial;                 /* Result of special query */

  /* "rank" function. Populated on demand from vtab.xColumn(). */
  char *zRank;                    /* Custom rank function */
  char *zRankArgs;                /* Custom rank function args */
  Fts5Auxiliary *pRank;           /* Rank callback (or NULL) */
  int nRankArg;                   /* Number of trailing arguments for rank() */
  sqlite3_value **apRankArg;      /* Array of trailing arguments */
................................................................................
    /* Remove the cursor from the Fts5Global.pCsr list */
    for(pp=&pTab->pGlobal->pCsr; (*pp)!=pCsr; pp=&(*pp)->pNext);
    *pp = pCsr->pNext;

    sqlite3_finalize(pCsr->pRankArgStmt);
    sqlite3_free(pCsr->apRankArg);

    sqlite3_free(pCsr->zSpecial);
    if( CsrFlagTest(pCsr, FTS5CSR_FREE_ZRANK) ){
      sqlite3_free(pCsr->zRank);
      sqlite3_free(pCsr->zRankArgs);
    }
    sqlite3_free(pCsr);
  }
  return SQLITE_OK;
................................................................................
  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;
  }

................................................................................
    sqlite3_result_error(context, zErr, -1);
    sqlite3_free(zErr);
  }else{
    fts5ApiInvoke(pAux, pCsr, context, argc-1, &argv[1]);
  }
}





















/*
** Return a "position-list blob" corresponding to the current position of
** cursor pCsr via sqlite3_result_blob(). A position-list blob contains
** the current position-list for each phrase in the query associated with
** cursor pCsr.
**
** A position-list blob begins with (nPhrase-1) varints, where nPhrase is
................................................................................
  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 ){
    /* 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
    ** useful in that it may be passed as the first argument to an FTS5
................................................................................
    pGlobal->api.xCreateTokenizer = fts5CreateTokenizer;
    pGlobal->api.xFindTokenizer = fts5FindTokenizer;
    rc = sqlite3_create_module_v2(db, "fts5", &fts5Mod, p, fts5ModuleDestroy);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5IndexInit(db);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5ExprInit(pGlobal, db);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5AuxInit(&pGlobal->api);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5TokenizerInit(&pGlobal->api);

    if( rc==SQLITE_OK ){
      rc = sqlite3_create_function(
          db, "fts5", 0, SQLITE_UTF8, p, fts5Fts5Func, 0, 0
      );
    }
  }
  return rc;
}
#endif /* defined(SQLITE_ENABLE_FTS5) */

  int aIdx[0];                    /* Offsets into aPoslist for current row */
};


/*
** Virtual-table cursor object.
**
** iSpecial:
**   If this is a 'special' query (refer to function fts5SpecialMatch()), 
**   then this variable contains the result of the query. 


*/
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 */
  i64 iSpecial;                   /* Result of special query */

  /* "rank" function. Populated on demand from vtab.xColumn(). */
  char *zRank;                    /* Custom rank function */
  char *zRankArgs;                /* Custom rank function args */
  Fts5Auxiliary *pRank;           /* Rank callback (or NULL) */
  int nRankArg;                   /* Number of trailing arguments for rank() */
  sqlite3_value **apRankArg;      /* Array of trailing arguments */
................................................................................
    /* Remove the cursor from the Fts5Global.pCsr list */
    for(pp=&pTab->pGlobal->pCsr; (*pp)!=pCsr; pp=&(*pp)->pNext);
    *pp = pCsr->pNext;

    sqlite3_finalize(pCsr->pRankArgStmt);
    sqlite3_free(pCsr->apRankArg);


    if( CsrFlagTest(pCsr, FTS5CSR_FREE_ZRANK) ){
      sqlite3_free(pCsr->zRank);
      sqlite3_free(pCsr->zRankArgs);
    }
    sqlite3_free(pCsr);
  }
  return SQLITE_OK;
................................................................................
  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 );
  pCsr->idxNum = FTS5_PLAN_SPECIAL;

  if( 0==sqlite3_strnicmp("reads", z, n) ){
    pCsr->iSpecial = sqlite3Fts5IndexReads(pTab->pIndex);

  }
  else if( 0==sqlite3_strnicmp("id", z, n) ){
    pCsr->iSpecial = pCsr->iCsrId;
  }
  else{
    /* An unrecognized directive. Return an error message. */
    pTab->base.zErrMsg = sqlite3_mprintf("unknown special query: %.*s", n, z);
    rc = SQLITE_ERROR;
  }

................................................................................
    sqlite3_result_error(context, zErr, -1);
    sqlite3_free(zErr);
  }else{
    fts5ApiInvoke(pAux, pCsr, context, argc-1, &argv[1]);
  }
}


/*
** Given cursor id iId, return a pointer to the corresponding Fts5Index 
** object. Or NULL If the cursor id does not exist.
*/
Fts5Index *sqlite3Fts5IndexFromCsrid(Fts5Global *pGlobal, i64 iCsrId){
  Fts5Cursor *pCsr;
  Fts5Index *pIndex = 0;

  for(pCsr=pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
    if( pCsr->iCsrId==iCsrId ) break;
  }
  if( pCsr ){
    Fts5Table *pTab = (Fts5Table*)pCsr->base.pVtab;
    pIndex = pTab->pIndex;
  }

  return pIndex;
}

/*
** Return a "position-list blob" corresponding to the current position of
** cursor pCsr via sqlite3_result_blob(). A position-list blob contains
** the current position-list for each phrase in the query associated with
** cursor pCsr.
**
** A position-list blob begins with (nPhrase-1) varints, where nPhrase is
................................................................................
  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_int64(pCtx, pCsr->iSpecial);
    }
  }else

  if( iCol==pConfig->nCol ){
    /* 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
    ** useful in that it may be passed as the first argument to an FTS5
................................................................................
    pGlobal->api.xCreateTokenizer = fts5CreateTokenizer;
    pGlobal->api.xFindTokenizer = fts5FindTokenizer;
    rc = sqlite3_create_module_v2(db, "fts5", &fts5Mod, p, fts5ModuleDestroy);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5IndexInit(db);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5ExprInit(pGlobal, db);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5AuxInit(&pGlobal->api);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5TokenizerInit(&pGlobal->api);
    if( rc==SQLITE_OK ) rc = sqlite3Fts5VocabInit(pGlobal, db);
    if( rc==SQLITE_OK ){
      rc = sqlite3_create_function(
          db, "fts5", 0, SQLITE_UTF8, p, fts5Fts5Func, 0, 0
      );
    }
  }
  return rc;
}
#endif /* defined(SQLITE_ENABLE_FTS5) */

#ifdef SQLITE_TEST
extern int sqlite3_fts5_may_be_corrupt;
# define assert_nc(x) assert(sqlite3_fts5_may_be_corrupt || (x))
#else
# define assert_nc(x) assert(x)
#endif

/**************************************************************************
** Interface to code in fts5.c. 
*/
typedef struct Fts5Global Fts5Global;

int sqlite3Fts5GetTokenizer(
  Fts5Global*, 
  const char **azArg,
  int nArg,
  Fts5Tokenizer**,
  fts5_tokenizer**,
  char **pzErr
);

/*
** End of interface to code in fts5.c.
**************************************************************************/

/**************************************************************************
** Interface to code in fts5_config.c. fts5_config.c contains contains code
** to parse the arguments passed to the CREATE VIRTUAL TABLE statement.
*/

typedef struct Fts5Config Fts5Config;

................................................................................

/*
** Values used as part of the flags argument passed to IndexQuery().
*/
#define FTS5INDEX_QUERY_PREFIX     0x0001   /* Prefix query */
#define FTS5INDEX_QUERY_DESC       0x0002   /* Docs in descending rowid order */
#define FTS5INDEX_QUERY_TEST_NOIDX 0x0004   /* Do not use prefix index */


/*
** Create/destroy an Fts5Index object.
*/
int sqlite3Fts5IndexOpen(Fts5Config *pConfig, int bCreate, Fts5Index**, char**);
int sqlite3Fts5IndexClose(Fts5Index *p);

................................................................................
i64 sqlite3Fts5IterRowid(Fts5IndexIter*);
int sqlite3Fts5IterPoslist(Fts5IndexIter*, const u8 **pp, int *pn);

/*
** Close an iterator opened by sqlite3Fts5IndexQuery().
*/
void sqlite3Fts5IterClose(Fts5IndexIter*);








/*
** Insert or remove data to or from the index. Each time a document is 
** added to or removed from the index, this function is called one or more
** times.
**
** For an insert, it must be called once for each token in the new document.
................................................................................
#define fts5GetVarint32(a,b) sqlite3Fts5GetVarint32(a,(u32*)&b)

int sqlite3Fts5GetVarintLen(u32 iVal);

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




















/**************************************************************************
** Interface to code in fts5_hash.c. 
*/
typedef struct Fts5Hash Fts5Hash;

/*
................................................................................
typedef struct Fts5Sorter Fts5Sorter;

int sqlite3Fts5SorterNew(Fts5Expr *pExpr, Fts5Sorter **pp);

/*
** End of interface to code in fts5_sorter.c.
**************************************************************************/











#endif

#ifdef SQLITE_TEST
extern int sqlite3_fts5_may_be_corrupt;
# define assert_nc(x) assert(sqlite3_fts5_may_be_corrupt || (x))
#else
# define assert_nc(x) assert(x)
#endif




typedef struct Fts5Global Fts5Global;














/**************************************************************************
** Interface to code in fts5_config.c. fts5_config.c contains contains code
** to parse the arguments passed to the CREATE VIRTUAL TABLE statement.
*/

typedef struct Fts5Config Fts5Config;

................................................................................

/*
** Values used as part of the flags argument passed to IndexQuery().
*/
#define FTS5INDEX_QUERY_PREFIX     0x0001   /* Prefix query */
#define FTS5INDEX_QUERY_DESC       0x0002   /* Docs in descending rowid order */
#define FTS5INDEX_QUERY_TEST_NOIDX 0x0004   /* Do not use prefix index */
#define FTS5INDEX_QUERY_SCAN       0x0008   /* Scan query (fts5vocab) */

/*
** Create/destroy an Fts5Index object.
*/
int sqlite3Fts5IndexOpen(Fts5Config *pConfig, int bCreate, Fts5Index**, char**);
int sqlite3Fts5IndexClose(Fts5Index *p);

................................................................................
i64 sqlite3Fts5IterRowid(Fts5IndexIter*);
int sqlite3Fts5IterPoslist(Fts5IndexIter*, const u8 **pp, int *pn);

/*
** Close an iterator opened by sqlite3Fts5IndexQuery().
*/
void sqlite3Fts5IterClose(Fts5IndexIter*);

/*
** This interface is used by the fts5vocab module.
*/
const char *sqlite3Fts5IterTerm(Fts5IndexIter*, int*);
int sqlite3Fts5IterNextScan(Fts5IndexIter*);


/*
** Insert or remove data to or from the index. Each time a document is 
** added to or removed from the index, this function is called one or more
** times.
**
** For an insert, it must be called once for each token in the new document.
................................................................................
#define fts5GetVarint32(a,b) sqlite3Fts5GetVarint32(a,(u32*)&b)

int sqlite3Fts5GetVarintLen(u32 iVal);

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

/**************************************************************************
** Interface to code in fts5.c. 
*/

int sqlite3Fts5GetTokenizer(
  Fts5Global*, 
  const char **azArg,
  int nArg,
  Fts5Tokenizer**,
  fts5_tokenizer**,
  char **pzErr
);

Fts5Index *sqlite3Fts5IndexFromCsrid(Fts5Global*, i64);

/*
** End of interface to code in fts5.c.
**************************************************************************/

/**************************************************************************
** Interface to code in fts5_hash.c. 
*/
typedef struct Fts5Hash Fts5Hash;

/*
................................................................................
typedef struct Fts5Sorter Fts5Sorter;

int sqlite3Fts5SorterNew(Fts5Expr *pExpr, Fts5Sorter **pp);

/*
** End of interface to code in fts5_sorter.c.
**************************************************************************/

/**************************************************************************
** Interface to code in fts5_vocab.c. 
*/

int sqlite3Fts5VocabInit(Fts5Global*, sqlite3*);

/*
** End of interface to code in fts5_vocab.c.
**************************************************************************/

#endif

  const u8 *pTerm, int nTerm,     /* Term to seek to */
  int flags,                      /* Mask of FTS5INDEX_XXX flags */
  Fts5StructureSegment *pSeg,     /* Description of segment */
  Fts5SegIter *pIter              /* Object to populate */
){
  int iPg = 1;
  int h;
  int bGe = (flags & FTS5INDEX_QUERY_PREFIX);
  int bDlidx = 0;                 /* True if there is a doclist-index */

  assert( bGe==0 || (flags & FTS5INDEX_QUERY_DESC)==0 );
  assert( pTerm && nTerm );
  memset(pIter, 0, sizeof(*pIter));
  pIter->pSeg = pSeg;

................................................................................
  int nList = 0;
  const u8 *z = 0;
  int n = 0;

  assert( p->pHash );
  assert( p->rc==SQLITE_OK );

  if( pTerm==0 || (flags & FTS5INDEX_QUERY_PREFIX) ){
    p->rc = sqlite3Fts5HashScanInit(p->pHash, (const char*)pTerm, nTerm);
    sqlite3Fts5HashScanEntry(p->pHash, (const char**)&z, &pList, &nList);
    n = (z ? strlen((const char*)z) : 0);
  }else{
    pIter->flags |= FTS5_SEGITER_ONETERM;
    sqlite3Fts5HashQuery(p->pHash, (const char*)pTerm, nTerm, &pList, &nList);
    z = pTerm;
................................................................................
  Fts5Buffer *aBuf;
  const int nBuf = 32;

  aBuf = (Fts5Buffer*)fts5IdxMalloc(p, sizeof(Fts5Buffer)*nBuf);
  pStruct = fts5StructureRead(p);

  if( aBuf && pStruct ){

    Fts5DoclistIter *pDoclist;
    int i;
    i64 iLastRowid = 0;
    Fts5MultiSegIter *p1 = 0;     /* Iterator used to gather data from index */
    Fts5Buffer doclist;

    memset(&doclist, 0, sizeof(doclist));
    for(fts5MultiIterNew(p, pStruct, 1, 1, pToken, nToken, -1, 0, &p1);
        fts5MultiIterEof(p, p1)==0;
        fts5MultiIterNext(p, p1, 0, 0)
    ){
      i64 iRowid = fts5MultiIterRowid(p1);
      int nTerm;
      const u8 *pTerm = fts5MultiIterTerm(p1, &nTerm);
      assert( memcmp(pToken, pTerm, MIN(nToken, nTerm))<=0 );
................................................................................
  int flags,                      /* Mask of FTS5INDEX_QUERY_X flags */
  Fts5IndexIter **ppIter          /* OUT: New iterator object */
){
  Fts5Config *pConfig = p->pConfig;
  Fts5IndexIter *pRet;
  int iIdx = 0;
  Fts5Buffer buf = {0, 0, 0};






  if( sqlite3Fts5BufferGrow(&p->rc, &buf, nToken+1)==0 ){
    memcpy(&buf.p[1], pToken, nToken);
  }

  if( flags & FTS5INDEX_QUERY_PREFIX ){
    if( flags & FTS5INDEX_QUERY_TEST_NOIDX ){
................................................................................
    memset(pRet, 0, sizeof(Fts5IndexIter));

    pRet->pIndex = p;
    if( iIdx<=pConfig->nPrefix ){
      buf.p[0] = FTS5_MAIN_PREFIX + iIdx;
      pRet->pStruct = fts5StructureRead(p);
      if( pRet->pStruct ){
        int f = (flags & ~FTS5INDEX_QUERY_PREFIX);
        fts5MultiIterNew(
            p, pRet->pStruct, 1, f, buf.p, nToken+1, -1, 0, &pRet->pMulti
        );
      }
    }else{
      int bDesc = (flags & FTS5INDEX_QUERY_DESC)!=0;
      buf.p[0] = FTS5_MAIN_PREFIX;
      fts5SetupPrefixIter(p, bDesc, buf.p, nToken+1, pRet);
    }
................................................................................
    fts5DoclistIterNext(pIter->pDoclist);
  }else{
    fts5BufferZero(&pIter->poslist);
    fts5MultiIterNext(pIter->pIndex, pIter->pMulti, 0, 0);
  }
  return fts5IndexReturn(pIter->pIndex);
}
























/*
** Move the doclist-iter passed as the first argument 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.
*/
................................................................................
i64 sqlite3Fts5IterRowid(Fts5IndexIter *pIter){
  if( pIter->pDoclist ){
    return pIter->pDoclist->iRowid;
  }else{
    return fts5MultiIterRowid(pIter->pMulti);
  }
}












/*
** Return a pointer to a buffer containing a copy of the position list for
** the current entry. Output variable *pn is set to the size of the buffer 
** in bytes before returning.
**

  const u8 *pTerm, int nTerm,     /* Term to seek to */
  int flags,                      /* Mask of FTS5INDEX_XXX flags */
  Fts5StructureSegment *pSeg,     /* Description of segment */
  Fts5SegIter *pIter              /* Object to populate */
){
  int iPg = 1;
  int h;
  int bGe = (flags & FTS5INDEX_QUERY_SCAN);
  int bDlidx = 0;                 /* True if there is a doclist-index */

  assert( bGe==0 || (flags & FTS5INDEX_QUERY_DESC)==0 );
  assert( pTerm && nTerm );
  memset(pIter, 0, sizeof(*pIter));
  pIter->pSeg = pSeg;

................................................................................
  int nList = 0;
  const u8 *z = 0;
  int n = 0;

  assert( p->pHash );
  assert( p->rc==SQLITE_OK );

  if( pTerm==0 || (flags & FTS5INDEX_QUERY_SCAN) ){
    p->rc = sqlite3Fts5HashScanInit(p->pHash, (const char*)pTerm, nTerm);
    sqlite3Fts5HashScanEntry(p->pHash, (const char**)&z, &pList, &nList);
    n = (z ? strlen((const char*)z) : 0);
  }else{
    pIter->flags |= FTS5_SEGITER_ONETERM;
    sqlite3Fts5HashQuery(p->pHash, (const char*)pTerm, nTerm, &pList, &nList);
    z = pTerm;
................................................................................
  Fts5Buffer *aBuf;
  const int nBuf = 32;

  aBuf = (Fts5Buffer*)fts5IdxMalloc(p, sizeof(Fts5Buffer)*nBuf);
  pStruct = fts5StructureRead(p);

  if( aBuf && pStruct ){
    const int flags = FTS5INDEX_QUERY_SCAN;
    Fts5DoclistIter *pDoclist;
    int i;
    i64 iLastRowid = 0;
    Fts5MultiSegIter *p1 = 0;     /* Iterator used to gather data from index */
    Fts5Buffer doclist;

    memset(&doclist, 0, sizeof(doclist));
    for(fts5MultiIterNew(p, pStruct, 1, flags, pToken, nToken, -1, 0, &p1);
        fts5MultiIterEof(p, p1)==0;
        fts5MultiIterNext(p, p1, 0, 0)
    ){
      i64 iRowid = fts5MultiIterRowid(p1);
      int nTerm;
      const u8 *pTerm = fts5MultiIterTerm(p1, &nTerm);
      assert( memcmp(pToken, pTerm, MIN(nToken, nTerm))<=0 );
................................................................................
  int flags,                      /* Mask of FTS5INDEX_QUERY_X flags */
  Fts5IndexIter **ppIter          /* OUT: New iterator object */
){
  Fts5Config *pConfig = p->pConfig;
  Fts5IndexIter *pRet;
  int iIdx = 0;
  Fts5Buffer buf = {0, 0, 0};

  /* If the QUERY_SCAN flag is set, all other flags must be clear. */
  assert( (flags & FTS5INDEX_QUERY_SCAN)==0
       || (flags & FTS5INDEX_QUERY_SCAN)==FTS5INDEX_QUERY_SCAN
  );

  if( sqlite3Fts5BufferGrow(&p->rc, &buf, nToken+1)==0 ){
    memcpy(&buf.p[1], pToken, nToken);
  }

  if( flags & FTS5INDEX_QUERY_PREFIX ){
    if( flags & FTS5INDEX_QUERY_TEST_NOIDX ){
................................................................................
    memset(pRet, 0, sizeof(Fts5IndexIter));

    pRet->pIndex = p;
    if( iIdx<=pConfig->nPrefix ){
      buf.p[0] = FTS5_MAIN_PREFIX + iIdx;
      pRet->pStruct = fts5StructureRead(p);
      if( pRet->pStruct ){

        fts5MultiIterNew(
            p, pRet->pStruct, 1, flags, buf.p, nToken+1, -1, 0, &pRet->pMulti
        );
      }
    }else{
      int bDesc = (flags & FTS5INDEX_QUERY_DESC)!=0;
      buf.p[0] = FTS5_MAIN_PREFIX;
      fts5SetupPrefixIter(p, bDesc, buf.p, nToken+1, pRet);
    }
................................................................................
    fts5DoclistIterNext(pIter->pDoclist);
  }else{
    fts5BufferZero(&pIter->poslist);
    fts5MultiIterNext(pIter->pIndex, pIter->pMulti, 0, 0);
  }
  return fts5IndexReturn(pIter->pIndex);
}

/*
** Move to the next matching term/rowid. Used by the fts5vocab module.
*/
int sqlite3Fts5IterNextScan(Fts5IndexIter *pIter){
  Fts5Index *p = pIter->pIndex;
  Fts5MultiSegIter *pMulti = pIter->pMulti;

  assert( pIter->pIndex->rc==SQLITE_OK );
  assert( pMulti );

  fts5BufferZero(&pIter->poslist);
  fts5MultiIterNext(p, pMulti, 0, 0);
  if( p->rc==SQLITE_OK ){
    Fts5SegIter *pSeg = &pMulti->aSeg[ pMulti->aFirst[1].iFirst ];
    if( pSeg->pLeaf && pSeg->term.p[0]!=FTS5_MAIN_PREFIX ){
      fts5DataRelease(pSeg->pLeaf);
      pSeg->pLeaf = 0;
    }
  }

  return fts5IndexReturn(pIter->pIndex);
}

/*
** Move the doclist-iter passed as the first argument 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.
*/
................................................................................
i64 sqlite3Fts5IterRowid(Fts5IndexIter *pIter){
  if( pIter->pDoclist ){
    return pIter->pDoclist->iRowid;
  }else{
    return fts5MultiIterRowid(pIter->pMulti);
  }
}

/*
** Return the current term.
*/
const char *sqlite3Fts5IterTerm(Fts5IndexIter *pIter, int *pn){
  int n;
  const char *z = fts5MultiIterTerm(pIter->pMulti, &n);
  *pn = n-1;
  return &z[1];
}


/*
** Return a pointer to a buffer containing a copy of the position list for
** the current entry. Output variable *pn is set to the size of the buffer 
** in bytes before returning.
**

/*
** 2015 May 08
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This is an SQLite module implementing full-text search.
*/

#if defined(SQLITE_ENABLE_FTS5)

#include "fts5Int.h"


typedef struct Fts5VocabTable Fts5VocabTable;
typedef struct Fts5VocabCursor Fts5VocabCursor;

struct Fts5VocabTable {
  sqlite3_vtab base;
  char *zFts5Tbl;                 /* Name of fts5 table */
  char *zFts5Db;                  /* Db containing fts5 table */
  sqlite3 *db;                    /* Database handle */
  Fts5Global *pGlobal;            /* FTS5 global object for this database */
};

struct Fts5VocabCursor {
  sqlite3_vtab_cursor base;
  sqlite3_stmt *pStmt;            /* Statement holding lock on pIndex */
  Fts5Index *pIndex;              /* Associated FTS5 index */

  Fts5IndexIter *pIter;           /* Iterator object */
  int bEof;                       /* True if this cursor is at EOF */
  Fts5Buffer term;                /* Current value of 'term' column */
  i64 nRow;                       /* Current value of 'row' column */
  i64 nInst;                      /* Current value of 'inst' column */
  i64 rowid;                      /* Current value of rowid column */
};


/*
** The xDisconnect() virtual table method.
*/
static int fts5VocabDisconnectMethod(sqlite3_vtab *pVtab){
  Fts5VocabTable *pTab = (Fts5VocabTable*)pVtab;
  sqlite3_free(pTab);
  return SQLITE_OK;
}

/*
** The xDestroy() virtual table method.
*/
static int fts5VocabDestroyMethod(sqlite3_vtab *pVtab){
  Fts5VocabTable *pTab = (Fts5VocabTable*)pVtab;
  sqlite3_free(pTab);
  return SQLITE_OK;
}

/*
** This function is the implementation of both the xConnect and xCreate
** methods of the FTS3 virtual table.
**
** The argv[] array contains the following:
**
**   argv[0]   -> module name  ("fts5vocab")
**   argv[1]   -> database name
**   argv[2]   -> table name
**   argv[3]   -> name of fts5 table
*/
static int fts5VocabInitVtab(
  sqlite3 *db,                    /* The SQLite database connection */
  void *pAux,                     /* Pointer to Fts5Global object */
  int argc,                       /* Number of elements in argv array */
  const char * const *argv,       /* xCreate/xConnect argument array */
  sqlite3_vtab **ppVTab,          /* Write the resulting vtab structure here */
  char **pzErr                    /* Write any error message here */
){
  const char *zSchema = "CREATE TABLE vvv(term, row, inst)";
  Fts5VocabTable *pRet = 0;
  int rc = SQLITE_OK;             /* Return code */

  if( argc!=4 ){
    *pzErr = sqlite3_mprintf("wrong number of vtable arguments");
    rc = SQLITE_ERROR;
  }else{
    int nByte;                      /* Bytes of space to allocate */
    const char *zDb = argv[1];
    const char *zTab = argv[3];
    int nDb = strlen(zDb) + 1;
    int nTab = strlen(zTab) + 1;

    rc = sqlite3_declare_vtab(db, zSchema);

    nByte = sizeof(Fts5VocabTable) + nDb + nTab;
    pRet = sqlite3Fts5MallocZero(&rc, nByte);
    if( pRet ){
      pRet->pGlobal = (Fts5Global*)pAux;
      pRet->db = db;
      pRet->zFts5Tbl = (char*)&pRet[1];
      pRet->zFts5Db = &pRet->zFts5Tbl[nTab];
      memcpy(pRet->zFts5Tbl, zTab, nTab);
      memcpy(pRet->zFts5Db, zDb, nDb);
    }
  }

  *ppVTab = (sqlite3_vtab*)pRet;
  return rc;
}


/*
** The xConnect() and xCreate() methods for the virtual table. All the
** work is done in function fts5VocabInitVtab().
*/
static int fts5VocabConnectMethod(
  sqlite3 *db,                    /* Database connection */
  void *pAux,                     /* Pointer to tokenizer hash table */
  int argc,                       /* Number of elements in argv array */
  const char * const *argv,       /* xCreate/xConnect argument array */
  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
){
  return fts5VocabInitVtab(db, pAux, argc, argv, ppVtab, pzErr);
}
static int fts5VocabCreateMethod(
  sqlite3 *db,                    /* Database connection */
  void *pAux,                     /* Pointer to tokenizer hash table */
  int argc,                       /* Number of elements in argv array */
  const char * const *argv,       /* xCreate/xConnect argument array */
  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
){
  return fts5VocabInitVtab(db, pAux, argc, argv, ppVtab, pzErr);
}

/* 
** Implementation of the xBestIndex method.
*/
static int fts5VocabBestIndexMethod(
  sqlite3_vtab *pVTab, 
  sqlite3_index_info *pInfo
){
  return SQLITE_OK;
}

/*
** Implementation of xOpen method.
*/
static int fts5VocabOpenMethod(
  sqlite3_vtab *pVTab, 
  sqlite3_vtab_cursor **ppCsr
){
  Fts5VocabTable *pTab = (Fts5VocabTable*)pVTab;
  Fts5VocabCursor *pCsr;
  int rc = SQLITE_OK;

  pCsr = (Fts5VocabCursor*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5VocabCursor));
  if( pCsr ){
    char *zSql = sqlite3_mprintf(
        "SELECT t.%Q FROM %Q.%Q AS t WHERE t.%Q MATCH '*id'",
        pTab->zFts5Tbl, pTab->zFts5Db, pTab->zFts5Tbl, pTab->zFts5Tbl
    );
    if( zSql==0 ){
      rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pStmt, 0);
    }
    sqlite3_free(zSql);
    if( rc==SQLITE_OK && sqlite3_step(pCsr->pStmt)==SQLITE_ROW ){
      i64 iId = sqlite3_column_int64(pCsr->pStmt, 0);
      pCsr->pIndex = sqlite3Fts5IndexFromCsrid(pTab->pGlobal, iId);
    }

    if( rc==SQLITE_OK && pCsr->pIndex==0 ){
      rc = sqlite3_finalize(pCsr->pStmt);
      pCsr->pStmt = 0;
      if( rc==SQLITE_OK ){
        pVTab->zErrMsg = sqlite3_mprintf(
            "no such fts5 table: %Q.%Q", pTab->zFts5Db, pTab->zFts5Tbl
        );
        rc = SQLITE_ERROR;
      }
    }

    if( rc!=SQLITE_OK ){
      sqlite3_free(pCsr);
      pCsr = 0;
    }
  }


  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
  return rc;
}

static void fts5VocabResetCursor(Fts5VocabCursor *pCsr){
  pCsr->rowid = 0;
  sqlite3Fts5IterClose(pCsr->pIter);
  pCsr->pIter = 0;
}

/*
** Close the cursor.  For additional information see the documentation
** on the xClose method of the virtual table interface.
*/
static int fts5VocabCloseMethod(sqlite3_vtab_cursor *pCursor){
  if( pCursor ){
    Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
    fts5VocabResetCursor(pCsr);
    sqlite3Fts5BufferFree(&pCsr->term);
    sqlite3_finalize(pCsr->pStmt);
    sqlite3_free(pCsr);
  }
  return SQLITE_OK;
}


/*
** Advance the cursor to the next row in the table.
*/
static int fts5VocabNextMethod(sqlite3_vtab_cursor *pCursor){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  int rc = SQLITE_OK;

  if( sqlite3Fts5IterEof(pCsr->pIter) ){
    pCsr->bEof = 1;
  }else{
    const char *zTerm;
    int nTerm;

    zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
    sqlite3Fts5BufferSet(&rc, &pCsr->term, nTerm, (const u8*)zTerm);
    pCsr->nInst = 0;
    pCsr->nRow = 0;
    pCsr->rowid++;

    while( 1 ){
      const u8 *pPos; int nPos;   /* Position list */
      i64 dummy = 0;
      int iOff = 0;

      rc = sqlite3Fts5IterPoslist(pCsr->pIter, &pPos, &nPos);
      if( rc!=SQLITE_OK ) break;
      while( 0==sqlite3Fts5PoslistNext64(pPos, nPos, &iOff, &dummy) ){
        pCsr->nInst++;
      }
      pCsr->nRow++;

      rc = sqlite3Fts5IterNextScan(pCsr->pIter);
      if( rc!=SQLITE_OK ) break;
      zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
      if( nTerm!=pCsr->term.n || memcmp(zTerm, pCsr->term.p, nTerm) ) break;
      if( sqlite3Fts5IterEof(pCsr->pIter) ) break;
    }
  }
  return rc;
}

/*
** This is the xFilter implementation for the virtual table.
*/
static int fts5VocabFilterMethod(
  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
  int idxNum,                     /* Strategy index */
  const char *idxStr,             /* Unused */
  int nVal,                       /* Number of elements in apVal */
  sqlite3_value **apVal           /* Arguments for the indexing scheme */
){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  int rc;
  const int flags = FTS5INDEX_QUERY_SCAN;

  fts5VocabResetCursor(pCsr);
  rc = sqlite3Fts5IndexQuery(pCsr->pIndex, 0, 0, flags, &pCsr->pIter);
  if( rc==SQLITE_OK ){
    rc = fts5VocabNextMethod(pCursor);
  }

  return rc;
}

/* 
** This is the xEof method of the virtual table. SQLite calls this 
** routine to find out if it has reached the end of a result set.
*/
static int fts5VocabEofMethod(sqlite3_vtab_cursor *pCursor){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  return pCsr->bEof;
}

static int fts5VocabColumnMethod(
  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
  int iCol                        /* Index of column to read value from */
){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  switch( iCol ){
    case 0: /* term */
      sqlite3_result_text(
          pCtx, (const char*)pCsr->term.p, pCsr->term.n, SQLITE_TRANSIENT
      );
      break;

    case 1: /* row */
      sqlite3_result_int64(pCtx, pCsr->nRow);
      break;

    case 2: /* inst */
      sqlite3_result_int64(pCtx, pCsr->nInst);
      break;

    default:
      assert( 0 );
  }
  return SQLITE_OK;
}

/* 
** This is the xRowid method. The SQLite core calls this routine to
** retrieve the rowid for the current row of the result set. fts5
** exposes %_content.docid as the rowid for the virtual table. The
** rowid should be written to *pRowid.
*/
static int fts5VocabRowidMethod(
  sqlite3_vtab_cursor *pCursor, 
  sqlite_int64 *pRowid
){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  *pRowid = pCsr->rowid;
  return SQLITE_OK;
}

int sqlite3Fts5VocabInit(Fts5Global *pGlobal, sqlite3 *db){
  static const sqlite3_module fts5Vocab = {
    /* iVersion      */ 2,
    /* xCreate       */ fts5VocabCreateMethod,
    /* xConnect      */ fts5VocabConnectMethod,
    /* xBestIndex    */ fts5VocabBestIndexMethod,
    /* xDisconnect   */ fts5VocabDisconnectMethod,
    /* xDestroy      */ fts5VocabDestroyMethod,
    /* xOpen         */ fts5VocabOpenMethod,
    /* xClose        */ fts5VocabCloseMethod,
    /* xFilter       */ fts5VocabFilterMethod,
    /* xNext         */ fts5VocabNextMethod,
    /* xEof          */ fts5VocabEofMethod,
    /* xColumn       */ fts5VocabColumnMethod,
    /* xRowid        */ fts5VocabRowidMethod,
    /* xUpdate       */ 0,
    /* xBegin        */ 0,
    /* xSync         */ 0,
    /* xCommit       */ 0,
    /* xRollback     */ 0,
    /* xFindFunction */ 0,
    /* xRename       */ 0,
    /* xSavepoint    */ 0,
    /* xRelease      */ 0,
    /* xRollbackTo   */ 0,
  };
  void *p = (void*)pGlobal;

  return sqlite3_create_module_v2(db, "fts5vocab", &fts5Vocab, p, 0);
}
#endif /* defined(SQLITE_ENABLE_FTS5) */

# 2015 Apr 24
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# The tests in this file focus on testing the fts5vocab module.
#

source [file join [file dirname [info script]] fts5_common.tcl]
set testprefix fts5vocab


do_execsql_test 1.1 {
  CREATE VIRTUAL TABLE t1 USING fts5(one, prefix=1);
  CREATE VIRTUAL TABLE v1 USING fts5vocab(t1);
  PRAGMA table_info = v1;
} {
  0 term {} 0 {} 0
  1 row {} 0 {} 0
  2 inst {} 0 {} 0
}

do_execsql_test 1.2 { SELECT * FROM v1 } { }

do_execsql_test 1.3 {
  INSERT INTO t1 VALUES('x y z');
  INSERT INTO t1 VALUES('x x x');
}

do_execsql_test 1.4 {
  SELECT * FROM v1;
} {x 2 4  y 1 1  z 1 1}

do_execsql_test 1.5 {
  BEGIN;
    INSERT INTO t1 VALUES('a b c');
    SELECT * FROM v1 WHERE term<'d';
  COMMIT;
} {a 1 1   b 1 1   c 1 1}

do_execsql_test 1.6 {
  DELETE FROM t1 WHERE one = 'a b c';
  SELECT * FROM v1;
} {x 2 4  y 1 1  z 1 1}



finish_test

LIBOBJ += fts5_config.o
LIBOBJ += fts5_expr.o
LIBOBJ += fts5_hash.o
LIBOBJ += fts5_index.o
LIBOBJ += fts5_storage.o
LIBOBJ += fts5_tokenize.o
LIBOBJ += fts5_unicode2.o

LIBOBJ += fts5parse.o



# All of the source code files.
#
SRC = \
................................................................................
   $(TOP)/ext/fts5/fts5_config.c \
   $(TOP)/ext/fts5/fts5_expr.c \
   $(TOP)/ext/fts5/fts5_hash.c \
   $(TOP)/ext/fts5/fts5_index.c \
   fts5parse.c fts5parse.h \
   $(TOP)/ext/fts5/fts5_storage.c \
   $(TOP)/ext/fts5/fts5_tokenize.c \
   $(TOP)/ext/fts5/fts5_unicode2.c 



# Generated source code files
#
SRC += \
  keywordhash.h \
  opcodes.c \
................................................................................
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts5/fts5_storage.c

fts5_tokenize.o:	$(TOP)/ext/fts5/fts5_tokenize.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts5/fts5_tokenize.c

fts5_unicode2.o:	$(TOP)/ext/fts5/fts5_unicode2.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts5/fts5_unicode2.c




fts5parse.c:	$(TOP)/ext/fts5/fts5parse.y lemon 
	cp $(TOP)/ext/fts5/fts5parse.y .
	rm -f fts5parse.h
	./lemon $(OPTS) fts5parse.y
	mv fts5parse.c fts5parse.c.orig
	echo "#ifdef SQLITE_ENABLE_FTS5" > fts5parse.c

LIBOBJ += fts5_config.o
LIBOBJ += fts5_expr.o
LIBOBJ += fts5_hash.o
LIBOBJ += fts5_index.o
LIBOBJ += fts5_storage.o
LIBOBJ += fts5_tokenize.o
LIBOBJ += fts5_unicode2.o
LIBOBJ += fts5_vocab.o
LIBOBJ += fts5parse.o



# All of the source code files.
#
SRC = \
................................................................................
   $(TOP)/ext/fts5/fts5_config.c \
   $(TOP)/ext/fts5/fts5_expr.c \
   $(TOP)/ext/fts5/fts5_hash.c \
   $(TOP)/ext/fts5/fts5_index.c \
   fts5parse.c fts5parse.h \
   $(TOP)/ext/fts5/fts5_storage.c \
   $(TOP)/ext/fts5/fts5_tokenize.c \
   $(TOP)/ext/fts5/fts5_unicode2.c \
   $(TOP)/ext/fts5/fts5_vocab.c 


# Generated source code files
#
SRC += \
  keywordhash.h \
  opcodes.c \
................................................................................
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts5/fts5_storage.c

fts5_tokenize.o:	$(TOP)/ext/fts5/fts5_tokenize.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts5/fts5_tokenize.c

fts5_unicode2.o:	$(TOP)/ext/fts5/fts5_unicode2.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts5/fts5_unicode2.c

fts5_vocab.o:	$(TOP)/ext/fts5/fts5_vocab.c $(HDR) $(EXTHDR)
	$(TCCX) -DSQLITE_CORE -c $(TOP)/ext/fts5/fts5_vocab.c

fts5parse.c:	$(TOP)/ext/fts5/fts5parse.y lemon 
	cp $(TOP)/ext/fts5/fts5parse.y .
	rm -f fts5parse.h
	./lemon $(OPTS) fts5parse.y
	mv fts5parse.c fts5parse.c.orig
	echo "#ifdef SQLITE_ENABLE_FTS5" > fts5parse.c