$(TOP)/src/test_syscall.c \
  $(TOP)/src/test_stat.c \
  $(TOP)/src/test_tclvar.c \
  $(TOP)/src/test_thread.c \
  $(TOP)/src/test_vfs.c \
  $(TOP)/src/test_wholenumber.c \
  $(TOP)/src/test_wsd.c       \
  $(TOP)/ext/fts3/fts3_term.c \
  $(TOP)/ext/fts3/fts3_test.c 

# Source code to the library files needed by the test fixture
#
TESTSRC2 = \
  $(TOP)/src/attach.c \
  $(TOP)/src/backup.c \
  $(TOP)/src/bitvec.c \

  *pVal += iVal;
}

/*
** When this function is called, *pp points to the first byte following a
** varint that is part of a doclist (or position-list, or any other list
** of varints). This function moves *pp to point to the start of that varint,
** and sets *pVal by the varint value.
**
** Argument pStart points to the first byte of the doclist that the
** varint is part of.
*/
static void fts3GetReverseVarint(
  char **pp, 
  char *pStart, 
  sqlite3_int64 *pVal
){
  sqlite3_int64 iVal;
  char *p = *pp;

  /* Pointer p now points at the first byte past the varint we are 
  ** interested in. So, unless the doclist is corrupt, the 0x80 bit is
  ** clear on character p[-1]. */
  for(p = (*pp)-2; p>=pStart && *p&0x80; p--);
  p++;
  *pp = p;

  sqlite3Fts3GetVarint(p, &iVal);
  *pVal = iVal;














}

/*
** The xDisconnect() virtual table method.
*/
static int fts3DisconnectMethod(sqlite3_vtab *pVtab){
  Fts3Table *p = (Fts3Table *)pVtab;

  fts3Appendf(pRc, &zRet, "?");
  for(i=0; i<p->nColumn; i++){
    fts3Appendf(pRc, &zRet, ",%s(?)", zFunction);
  }
  sqlite3_free(zFree);
  return zRet;
}

static int fts3GobbleInt(const char **pp, int *pnOut){
  const char *p = *pp;
  int nInt = 0;
  for(p=*pp; p[0]>='0' && p[0]<='9'; p++){
    nInt = nInt * 10 + (p[0] - '0');
  }
  if( p==*pp ) return SQLITE_ERROR;
  *pnOut = nInt;
  *pp = p;
  return SQLITE_OK;
}


static int fts3PrefixParameter(
  const char *zParam,             /* ABC in prefix=ABC parameter to parse */
  int *pnIndex,                   /* OUT: size of *apIndex[] array */
  struct Fts3Index **apIndex,     /* OUT: Array of indexes for this table */
  struct Fts3Index **apFree       /* OUT: Free this with sqlite3_free() */
){
  struct Fts3Index *aIndex;
  int nIndex = 1;

  if( zParam && zParam[0] ){
    const char *p;
    nIndex++;
    for(p=zParam; *p; p++){
      if( *p==',' ) nIndex++;
    }
  }

  aIndex = sqlite3_malloc(sizeof(struct Fts3Index) * nIndex);
  *apIndex = *apFree = aIndex;
  *pnIndex = nIndex;
  if( !aIndex ){
    return SQLITE_NOMEM;
  }

  memset(aIndex, 0, sizeof(struct Fts3Index) * nIndex);
  if( zParam ){
    const char *p = zParam;
    int i;
    for(i=1; i<nIndex; i++){
      int nPrefix;
      if( fts3GobbleInt(&p, &nPrefix) ) return SQLITE_ERROR;
      aIndex[i].nPrefix = nPrefix;
      p++;
    }
  }

  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:
**

  int iCol;                       /* Column index */
  int nString = 0;                /* Bytes required to hold all column names */
  int nCol = 0;                   /* Number of columns in the FTS table */
  char *zCsr;                     /* Space for holding column names */
  int nDb;                        /* Bytes required to hold database name */
  int nName;                      /* Bytes required to hold table name */
  int isFts4 = (argv[0][3]=='4'); /* True for FTS4, false for FTS3 */

  const char **aCol;              /* Array of column names */
  sqlite3_tokenizer *pTokenizer = 0;        /* Tokenizer for this table */

  int nIndex;                     /* Size of aIndex[] array */
  struct Fts3Index *aIndex;       /* Array of indexes for this table */
  struct Fts3Index *aFree = 0;    /* Free this before returning */

  /* The results of parsing supported FTS4 key=value options: */
  int bNoDocsize = 0;             /* True to omit %_docsize table */
  int bDescIdx = 0;               /* True to store descending indexes */
  char *zPrefix = 0;              /* Prefix parameter value (or NULL) */
  char *zCompress = 0;            /* compress=? parameter (or NULL) */
  char *zUncompress = 0;          /* uncompress=? parameter (or NULL) */

  assert( strlen(argv[0])==4 );
  assert( (sqlite3_strnicmp(argv[0], "fts4", 4)==0 && isFts4)
       || (sqlite3_strnicmp(argv[0], "fts3", 4)==0 && !isFts4)
  );

  nDb = (int)strlen(argv[1]) + 1;

     && 0==sqlite3Fts3IsIdChar(z[8])
    ){
      rc = sqlite3Fts3InitTokenizer(pHash, &z[9], &pTokenizer, pzErr);
    }

    /* Check if it is an FTS4 special argument. */
    else if( isFts4 && fts3IsSpecialColumn(z, &nKey, &zVal) ){
      struct Fts4Option {
        const char *zOpt;
        int nOpt;
        char **pzVar;
      } aFts4Opt[] = {
        { "matchinfo",   9, 0 },            /* 0 -> MATCHINFO */
        { "prefix",      6, 0 },            /* 1 -> PREFIX */
        { "compress",    8, 0 },            /* 2 -> COMPRESS */
        { "uncompress", 10, 0 },            /* 3 -> UNCOMPRESS */
        { "order",       5, 0 }             /* 4 -> ORDER */
      };

      int iOpt;
      if( !zVal ){
        rc = SQLITE_NOMEM;
      }else{
        for(iOpt=0; iOpt<SizeofArray(aFts4Opt); iOpt++){
          struct Fts4Option *pOp = &aFts4Opt[iOpt];
          if( nKey==pOp->nOpt && !sqlite3_strnicmp(z, pOp->zOpt, pOp->nOpt) ){
            break;
          }
        }
        if( iOpt==SizeofArray(aFts4Opt) ){
          *pzErr = sqlite3_mprintf("unrecognized parameter: %s", z);

          rc = SQLITE_ERROR;
        }else{
          switch( iOpt ){
            case 0:               /* MATCHINFO */
              if( strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "fts3", 4) ){
                *pzErr = sqlite3_mprintf("unrecognized matchinfo: %s", zVal);
                rc = SQLITE_ERROR;
              }
              bNoDocsize = 1;
              break;

            case 1:               /* PREFIX */
              sqlite3_free(zPrefix);
              zPrefix = zVal;
              zVal = 0;
              break;

            case 2:               /* COMPRESS */
              sqlite3_free(zCompress);
              zCompress = zVal;
              zVal = 0;
              break;

            case 3:               /* UNCOMPRESS */
              sqlite3_free(zUncompress);
              zUncompress = zVal;
              zVal = 0;
              break;

            case 4:               /* ORDER */
              if( (strlen(zVal)!=3 || sqlite3_strnicmp(zVal, "asc", 3)) 
               && (strlen(zVal)!=4 || sqlite3_strnicmp(zVal, "desc", 3)) 
              ){
                *pzErr = sqlite3_mprintf("unrecognized order: %s", zVal);
                rc = SQLITE_ERROR;
              }
              bDescIdx = (zVal[0]=='d' || zVal[0]=='D');
              break;
          }
        }
        sqlite3_free(zVal);
      }
    }

    /* Otherwise, the argument is a column name. */
    else {
      nString += (int)(strlen(z) + 1);
      aCol[nCol++] = z;
    }

  if( pTokenizer==0 ){
    rc = sqlite3Fts3InitTokenizer(pHash, "simple", &pTokenizer, pzErr);
    if( rc!=SQLITE_OK ) goto fts3_init_out;
  }
  assert( pTokenizer );

  rc = fts3PrefixParameter(zPrefix, &nIndex, &aIndex, &aFree);
  if( rc==SQLITE_ERROR ){
    assert( zPrefix );
    *pzErr = sqlite3_mprintf("error parsing prefix parameter: %s", zPrefix);
  }
  if( rc!=SQLITE_OK ) goto fts3_init_out;

  /* Allocate and populate the Fts3Table structure. */
  nByte = sizeof(Fts3Table) +                  /* Fts3Table */
          nCol * sizeof(char *) +              /* azColumn */
          nIndex * sizeof(struct Fts3Index) +  /* aIndex */
          nName +                              /* zName */
          nDb +                                /* zDb */
          nString;                             /* Space for azColumn strings */
  p = (Fts3Table*)sqlite3_malloc(nByte);
  if( p==0 ){
    rc = SQLITE_NOMEM;
    goto fts3_init_out;
  }
  memset(p, 0, nByte);
  p->db = db;
  p->nColumn = nCol;
  p->nPendingData = 0;
  p->azColumn = (char **)&p[1];
  p->pTokenizer = pTokenizer;

  p->nMaxPendingData = FTS3_MAX_PENDING_DATA;
  p->bHasDocsize = (isFts4 && bNoDocsize==0);
  p->bHasStat = isFts4;
  p->bDescIdx = bDescIdx;
  TESTONLY( p->inTransaction = -1 );
  TESTONLY( p->mxSavepoint = -1 );

  p->aIndex = (struct Fts3Index *)&p->azColumn[nCol];
  memcpy(p->aIndex, aIndex, sizeof(struct Fts3Index) * nIndex);
  p->nIndex = nIndex;
  for(i=0; i<nIndex; i++){
    fts3HashInit(&p->aIndex[i].hPending, FTS3_HASH_STRING, 1);
  }

  /* Fill in the zName and zDb fields of the vtab structure. */
  zCsr = (char *)&p->aIndex[nIndex];
  p->zName = zCsr;
  memcpy(zCsr, argv[2], nName);
  zCsr += nName;
  p->zDb = zCsr;
  memcpy(zCsr, argv[1], nDb);
  zCsr += nDb;

  ** database. TODO: For xConnect(), it could verify that said tables exist.
  */
  if( isCreate ){
    rc = fts3CreateTables(p);
  }

  /* Figure out the page-size for the database. This is required in order to
  ** estimate the cost of loading large doclists from the database.  */


  fts3DatabasePageSize(&rc, p);
  p->nNodeSize = p->nPgsz-35;

  /* Declare the table schema to SQLite. */
  fts3DeclareVtab(&rc, p);

fts3_init_out:
  sqlite3_free(zPrefix);
  sqlite3_free(aFree);
  sqlite3_free(zCompress);
  sqlite3_free(zUncompress);
  sqlite3_free((void *)aCol);
  if( rc!=SQLITE_OK ){
    if( p ){
      fts3DisconnectMethod((sqlite3_vtab *)p);
    }else if( pTokenizer ){
      pTokenizer->pModule->xDestroy(pTokenizer);
    }
  }else{
    assert( p->pSegments==0 );
    *ppVTab = &p->base;
  }
  return rc;
}

/*
** The xConnect() and xCreate() methods for the virtual table. All the

    struct sqlite3_index_orderby *pOrder = &pInfo->aOrderBy[0];
    if( pOrder->iColumn<0 || pOrder->iColumn==p->nColumn+1 ){
      if( pOrder->desc ){
        pInfo->idxStr = "DESC";
      }else{
        pInfo->idxStr = "ASC";
      }

      pInfo->orderByConsumed = 1;
    }
  }

  assert( p->pSegments==0 );
  return SQLITE_OK;
}

/*
** Implementation of xOpen method.
*/
static int fts3OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){

  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
  sqlite3_finalize(pCsr->pStmt);
  sqlite3Fts3ExprFree(pCsr->pExpr);
  sqlite3Fts3FreeDeferredTokens(pCsr);
  sqlite3_free(pCsr->aDoclist);
  sqlite3_free(pCsr->aMatchinfo);
  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** Position the pCsr->pStmt statement so that it is on the row
** of the %_content table that contains the last match.  Return
** SQLITE_OK on success.  
*/
static int fts3CursorSeek(sqlite3_context *pContext, Fts3Cursor *pCsr){
  if( pCsr->isRequireSeek ){

    sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);
    pCsr->isRequireSeek = 0;
    if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){
      return SQLITE_OK;
    }else{
      int rc = sqlite3_reset(pCsr->pStmt);
      if( rc==SQLITE_OK ){
        /* If no row was found and no error has occured, then the %_content
        ** table is missing a row that is present in the full-text index.

  assert( !piLeaf2 || !piLeaf || rc!=SQLITE_OK || (*piLeaf<=*piLeaf2) );

  if( rc==SQLITE_OK && iHeight>1 ){
    char *zBlob = 0;              /* Blob read from %_segments table */
    int nBlob;                    /* Size of zBlob in bytes */

    if( piLeaf && piLeaf2 && (*piLeaf!=*piLeaf2) ){
      rc = sqlite3Fts3ReadBlock(p, *piLeaf, &zBlob, &nBlob, 0);
      if( rc==SQLITE_OK ){
        rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, 0);
      }
      sqlite3_free(zBlob);
      piLeaf = 0;
      zBlob = 0;
    }

    if( rc==SQLITE_OK ){
      rc = sqlite3Fts3ReadBlock(p, piLeaf?*piLeaf:*piLeaf2, &zBlob, &nBlob, 0);
    }
    if( rc==SQLITE_OK ){
      rc = fts3SelectLeaf(p, zTerm, nTerm, zBlob, nBlob, piLeaf, piLeaf2);
    }
    sqlite3_free(zBlob);
  }

  }
  *p++ = 0x00;
  *pp = p;
  return 1;
}

/*
** Merge two position-lists as required by the NEAR operator. The argument
** position lists correspond to the left and right phrases of an expression 
** like:
**
**     "phrase 1" NEAR "phrase number 2"
**
** Position list *pp1 corresponds to the left-hand side of the NEAR 
** expression and *pp2 to the right. As usual, the indexes in the position 
** lists are the offsets of the last token in each phrase (tokens "1" and "2" 
** in the example above).
**
** The output position list - written to *pp - is a copy of *pp2 with those
** entries that are not sufficiently NEAR entries in *pp1 removed.
*/
static int fts3PoslistNearMerge(
  char **pp,                      /* Output buffer */
  char *aTmp,                     /* Temporary buffer space */
  int nRight,                     /* Maximum difference in token positions */
  int nLeft,                      /* Maximum difference in token positions */
  char **pp1,                     /* IN/OUT: Left input list */
  char **pp2                      /* IN/OUT: Right input list */
){
  char *p1 = *pp1;
  char *p2 = *pp2;







  char *pTmp1 = aTmp;
  char *pTmp2;
  char *aTmp2;
  int res = 1;

  fts3PoslistPhraseMerge(&pTmp1, nRight, 0, 0, pp1, pp2);
  aTmp2 = pTmp2 = pTmp1;
  *pp1 = p1;
  *pp2 = p2;
  fts3PoslistPhraseMerge(&pTmp2, nLeft, 1, 0, pp2, pp1);
  if( pTmp1!=aTmp && pTmp2!=aTmp2 ){
    fts3PoslistMerge(pp, &aTmp, &aTmp2);
  }else if( pTmp1!=aTmp ){
    fts3PoslistCopy(pp, &aTmp);
  }else if( pTmp2!=aTmp2 ){
    fts3PoslistCopy(pp, &aTmp2);
  }else{
    res = 0;
  }

  return res;





















































































































































































}

/* 
** A pointer to an instance of this structure is used as the context 
** argument to sqlite3Fts3SegReaderIterate()
*/
typedef struct TermSelect TermSelect;
struct TermSelect {
  int isReqPos;
  char *aaOutput[16];             /* Malloc'd output buffer */
  int anOutput[16];               /* Size of output in bytes */
};


static void fts3GetDeltaVarint3(
  char **pp, 
  char *pEnd, 
  int bDescIdx,
  sqlite3_int64 *pVal
){
  if( *pp>=pEnd ){
    *pp = 0;
  }else{
    sqlite3_int64 iVal;
    *pp += sqlite3Fts3GetVarint(*pp, &iVal);
    if( bDescIdx ){
      *pVal -= iVal;
    }else{
      *pVal += iVal;
    }
  }
}

static void fts3PutDeltaVarint3(
  char **pp,                      /* IN/OUT: Output pointer */
  int bDescIdx,                   /* True for descending docids */
  sqlite3_int64 *piPrev,          /* IN/OUT: Previous value written to list */
  int *pbFirst,                   /* IN/OUT: True after first int written */
  sqlite3_int64 iVal              /* Write this value to the list */
){
  sqlite3_int64 iWrite;
  if( bDescIdx==0 || *pbFirst==0 ){
    iWrite = iVal - *piPrev;
  }else{
    iWrite = *piPrev - iVal;
  }
  assert( *pbFirst || *piPrev==0 );
  assert( *pbFirst==0 || iWrite>0 );
  *pp += sqlite3Fts3PutVarint(*pp, iWrite);
  *piPrev = iVal;
  *pbFirst = 1;
}

#define COMPARE_DOCID(i1, i2) ((bDescIdx?-1:1) * (i1-i2))

static int fts3DoclistOrMerge(
  int bDescIdx,                   /* True if arguments are desc */
  char *a1, int n1,               /* First doclist */
  char *a2, int n2,               /* Second doclist */
  char **paOut, int *pnOut        /* OUT: Malloc'd doclist */
){
  sqlite3_int64 i1 = 0;
  sqlite3_int64 i2 = 0;
  sqlite3_int64 iPrev = 0;
  char *pEnd1 = &a1[n1];
  char *pEnd2 = &a2[n2];
  char *p1 = a1;
  char *p2 = a2;
  char *p;
  char *aOut;
  int bFirstOut = 0;

  *paOut = 0;
  *pnOut = 0;
  aOut = sqlite3_malloc(n1+n2);
  if( !aOut ) return SQLITE_NOMEM;

  p = aOut;
  fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1);
  fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2);
  while( p1 || p2 ){
    sqlite3_int64 iDiff = COMPARE_DOCID(i1, i2);

    if( p2 && p1 && iDiff==0 ){
      fts3PutDeltaVarint3(&p, bDescIdx, &iPrev, &bFirstOut, i1);
      fts3PoslistMerge(&p, &p1, &p2);
      fts3GetDeltaVarint3(&p1, pEnd1, bDescIdx, &i1);
      fts3GetDeltaVarint3(&p2, pEnd2, bDescIdx, &i2);
    }else if( !p2 || (p1 && iDiff<0) ){
      fts3PutDeltaVarint3(&p, bDescIdx, &iPrev, &bFirstOut, i1);
      fts3PoslistCopy(&p, &p1);
      fts3GetDeltaVarint3(&p1, pEnd1, bDescIdx, &i1);
    }else{
      fts3PutDeltaVarint3(&p, bDescIdx, &iPrev, &bFirstOut, i2);
      fts3PoslistCopy(&p, &p2);
      fts3GetDeltaVarint3(&p2, pEnd2, bDescIdx, &i2);
    }
  }

  *paOut = aOut;
  *pnOut = (p-aOut);
  return SQLITE_OK;
}

static void fts3DoclistPhraseMerge(
  int bDescIdx,                   /* True if arguments are desc */
  int nDist,                      /* Distance from left to right (1=adjacent) */
  char *aLeft, int nLeft,         /* Left doclist */
  char *aRight, int *pnRight      /* IN/OUT: Right/output doclist */
){
  sqlite3_int64 i1 = 0;
  sqlite3_int64 i2 = 0;
  sqlite3_int64 iPrev = 0;
  char *pEnd1 = &aLeft[nLeft];
  char *pEnd2 = &aRight[*pnRight];
  char *p1 = aLeft;
  char *p2 = aRight;
  char *p;
  int bFirstOut = 0;
  char *aOut = aRight;

  assert( nDist>0 );

  p = aOut;
  fts3GetDeltaVarint3(&p1, pEnd1, 0, &i1);
  fts3GetDeltaVarint3(&p2, pEnd2, 0, &i2);

  while( p1 && p2 ){
    sqlite3_int64 iDiff = COMPARE_DOCID(i1, i2);
    if( iDiff==0 ){
      char *pSave = p;
      sqlite3_int64 iPrevSave = iPrev;
      int bFirstOutSave = bFirstOut;

      fts3PutDeltaVarint3(&p, bDescIdx, &iPrev, &bFirstOut, i1);
      if( 0==fts3PoslistPhraseMerge(&p, nDist, 0, 1, &p1, &p2) ){
        p = pSave;
        iPrev = iPrevSave;
        bFirstOut = bFirstOutSave;
      }
      fts3GetDeltaVarint3(&p1, pEnd1, bDescIdx, &i1);
      fts3GetDeltaVarint3(&p2, pEnd2, bDescIdx, &i2);
    }else if( iDiff<0 ){
      fts3PoslistCopy(0, &p1);
      fts3GetDeltaVarint3(&p1, pEnd1, bDescIdx, &i1);
    }else{
      fts3PoslistCopy(0, &p2);
      fts3GetDeltaVarint3(&p2, pEnd2, bDescIdx, &i2);
    }
  }

  *pnRight = p - aOut;
}


/*
** Merge all doclists in the TermSelect.aaOutput[] array into a single
** doclist stored in TermSelect.aaOutput[0]. If successful, delete all
** other doclists (except the aaOutput[0] one) and return SQLITE_OK.
**
** If an OOM error occurs, return SQLITE_NOMEM. In this case it is
** the responsibility of the caller to free any doclists left in the
** TermSelect.aaOutput[] array.
*/
static int fts3TermSelectMerge(Fts3Table *p, TermSelect *pTS){

  char *aOut = 0;
  int nOut = 0;
  int i;

  /* Loop through the doclists in the aaOutput[] array. Merge them all
  ** into a single doclist.
  */
  for(i=0; i<SizeofArray(pTS->aaOutput); i++){
    if( pTS->aaOutput[i] ){
      if( !aOut ){
        aOut = pTS->aaOutput[i];
        nOut = pTS->anOutput[i];
        pTS->aaOutput[i] = 0;
      }else{
        int nNew;
        char *aNew;

        int rc = fts3DoclistOrMerge(p->bDescIdx, 
            pTS->aaOutput[i], pTS->anOutput[i], aOut, nOut, &aNew, &nNew
        );
        if( rc!=SQLITE_OK ){
          sqlite3_free(aOut);
          return rc;
        }



        sqlite3_free(pTS->aaOutput[i]);
        sqlite3_free(aOut);
        pTS->aaOutput[i] = 0;
        aOut = aNew;
        nOut = nNew;
      }
    }

  UNUSED_PARAMETER(p);
  UNUSED_PARAMETER(zTerm);
  UNUSED_PARAMETER(nTerm);

  if( pTS->aaOutput[0]==0 ){
    /* If this is the first term selected, copy the doclist to the output
    ** buffer using memcpy(). */


    pTS->aaOutput[0] = sqlite3_malloc(nDoclist);
    pTS->anOutput[0] = nDoclist;
    if( pTS->aaOutput[0] ){
      memcpy(pTS->aaOutput[0], aDoclist, nDoclist);
    }else{
      return SQLITE_NOMEM;
    }
  }else{

    char *aMerge = aDoclist;
    int nMerge = nDoclist;
    int iOut;

    for(iOut=0; iOut<SizeofArray(pTS->aaOutput); iOut++){


      if( pTS->aaOutput[iOut]==0 ){
        assert( iOut>0 );
        pTS->aaOutput[iOut] = aMerge;
        pTS->anOutput[iOut] = nMerge;
        break;
      }else{
        char *aNew;
        int nNew;

        int rc = fts3DoclistOrMerge(p->bDescIdx, aMerge, nMerge, 
            pTS->aaOutput[iOut], pTS->anOutput[iOut], &aNew, &nNew
        );
        if( rc!=SQLITE_OK ){
          if( aMerge!=aDoclist ) sqlite3_free(aMerge);


          return rc;
        }




        if( aMerge!=aDoclist ) sqlite3_free(aMerge);
        sqlite3_free(pTS->aaOutput[iOut]);
        pTS->aaOutput[iOut] = 0;
  
        aMerge = aNew;
        nMerge = nNew;
        if( (iOut+1)==SizeofArray(pTS->aaOutput) ){
          pTS->aaOutput[iOut] = aMerge;
          pTS->anOutput[iOut] = nMerge;
        }
      }
    }
  }
  return SQLITE_OK;
}

/*
** Append SegReader object pNew to the end of the pCsr->apSegment[] array.
*/
static int fts3SegReaderCursorAppend(
  Fts3MultiSegReader *pCsr, 
  Fts3SegReader *pNew



){
  if( (pCsr->nSegment%16)==0 ){
    Fts3SegReader **apNew;
    int nByte = (pCsr->nSegment + 16)*sizeof(Fts3SegReader*);
    apNew = (Fts3SegReader **)sqlite3_realloc(pCsr->apSegment, nByte);

    if( !apNew ){








      sqlite3Fts3SegReaderFree(pNew);


      return SQLITE_NOMEM;

    }
    pCsr->apSegment = apNew;
  }
  pCsr->apSegment[pCsr->nSegment++] = pNew;
  return SQLITE_OK;
}

static int fts3SegReaderCursor(
  Fts3Table *p,                   /* FTS3 table handle */
  int iIndex,                     /* Index to search (from 0 to p->nIndex-1) */
  int iLevel,                     /* Level of segments to scan */
  const char *zTerm,              /* Term to query for */
  int nTerm,                      /* Size of zTerm in bytes */
  int isPrefix,                   /* True for a prefix search */
  int isScan,                     /* True to scan from zTerm to EOF */
  Fts3MultiSegReader *pCsr       /* Cursor object to populate */
){
  int rc = SQLITE_OK;
  int rc2;

  sqlite3_stmt *pStmt = 0;




  /* If iLevel is less than 0 and this is not a scan, include a seg-reader 





  ** for the pending-terms. If this is a scan, then this call must be being
  ** made by an fts4aux module, not an FTS table. In this case calling
  ** Fts3SegReaderPending might segfault, as the data structures used by 
  ** fts4aux are not completely populated. So it's easiest to filter these


  ** calls out here.  */
  if( iLevel<0 && p->aIndex ){
    Fts3SegReader *pSeg = 0;
    rc = sqlite3Fts3SegReaderPending(p, iIndex, zTerm, nTerm, isPrefix, &pSeg);
    if( rc==SQLITE_OK && pSeg ){
      rc = fts3SegReaderCursorAppend(pCsr, pSeg);







    }
  }


  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
    if( rc==SQLITE_OK ){
      rc = sqlite3Fts3AllSegdirs(p, iIndex, iLevel, &pStmt);
    }

    while( rc==SQLITE_OK && SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
      Fts3SegReader *pSeg = 0;

      /* Read the values returned by the SELECT into local variables. */
      sqlite3_int64 iStartBlock = sqlite3_column_int64(pStmt, 1);
      sqlite3_int64 iLeavesEndBlock = sqlite3_column_int64(pStmt, 2);
      sqlite3_int64 iEndBlock = sqlite3_column_int64(pStmt, 3);
      int nRoot = sqlite3_column_bytes(pStmt, 4);
      char const *zRoot = sqlite3_column_blob(pStmt, 4);













      /* If zTerm is not NULL, and this segment is not stored entirely on its
      ** root node, the range of leaves scanned can be reduced. Do this. */
      if( iStartBlock && zTerm ){
        sqlite3_int64 *pi = (isPrefix ? &iLeavesEndBlock : 0);
        rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &iStartBlock, pi);
        if( rc!=SQLITE_OK ) goto finished;
        if( isPrefix==0 && isScan==0 ) iLeavesEndBlock = iStartBlock;
      }
 
      rc = sqlite3Fts3SegReaderNew(pCsr->nSegment+1, 
          iStartBlock, iLeavesEndBlock, iEndBlock, zRoot, nRoot, &pSeg
      );
      if( rc!=SQLITE_OK ) goto finished;
      rc = fts3SegReaderCursorAppend(pCsr, pSeg);

    }
  }

 finished:
  rc2 = sqlite3_reset(pStmt);
  if( rc==SQLITE_DONE ) rc = rc2;


  return rc;
}

/*
** Set up a cursor object for iterating through a full-text index or a 
** single level therein.
*/
int sqlite3Fts3SegReaderCursor(
  Fts3Table *p,                   /* FTS3 table handle */
  int iIndex,                     /* Index to search (from 0 to p->nIndex-1) */
  int iLevel,                     /* Level of segments to scan */
  const char *zTerm,              /* Term to query for */
  int nTerm,                      /* Size of zTerm in bytes */
  int isPrefix,                   /* True for a prefix search */
  int isScan,                     /* True to scan from zTerm to EOF */
  Fts3MultiSegReader *pCsr       /* Cursor object to populate */
){
  assert( iIndex>=0 && iIndex<p->nIndex );
  assert( iLevel==FTS3_SEGCURSOR_ALL
      ||  iLevel==FTS3_SEGCURSOR_PENDING 
      ||  iLevel>=0
  );
  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
  assert( FTS3_SEGCURSOR_ALL<0 && FTS3_SEGCURSOR_PENDING<0 );
  assert( isPrefix==0 || isScan==0 );

  /* "isScan" is only set to true by the ft4aux module, an ordinary
  ** full-text tables. */
  assert( isScan==0 || p->aIndex==0 );

  memset(pCsr, 0, sizeof(Fts3MultiSegReader));

  return fts3SegReaderCursor(
      p, iIndex, iLevel, zTerm, nTerm, isPrefix, isScan, pCsr
  );
}

static int fts3SegReaderCursorAddZero(
  Fts3Table *p,
  const char *zTerm,
  int nTerm,
  Fts3MultiSegReader *pCsr
){
  return fts3SegReaderCursor(p, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0,pCsr);
}


int sqlite3Fts3TermSegReaderCursor(
  Fts3Cursor *pCsr,               /* Virtual table cursor handle */
  const char *zTerm,              /* Term to query for */
  int nTerm,                      /* Size of zTerm in bytes */
  int isPrefix,                   /* True for a prefix search */
  Fts3MultiSegReader **ppSegcsr   /* OUT: Allocated seg-reader cursor */
){
  Fts3MultiSegReader *pSegcsr;   /* Object to allocate and return */
  int rc = SQLITE_NOMEM;          /* Return code */

  pSegcsr = sqlite3_malloc(sizeof(Fts3MultiSegReader));
  if( pSegcsr ){
    int i;
    int bFound = 0;               /* True once an index has been found */
    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;

    if( isPrefix ){
      for(i=1; bFound==0 && i<p->nIndex; i++){
        if( p->aIndex[i].nPrefix==nTerm ){
          bFound = 1;
          rc = sqlite3Fts3SegReaderCursor(
              p, i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0, pSegcsr);
          pSegcsr->bLookup = 1;
        }
      }

      for(i=1; bFound==0 && i<p->nIndex; i++){
        if( p->aIndex[i].nPrefix==nTerm+1 ){
          bFound = 1;
          rc = sqlite3Fts3SegReaderCursor(
              p, i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 1, 0, pSegcsr
          );
          if( rc==SQLITE_OK ){
            rc = fts3SegReaderCursorAddZero(p, zTerm, nTerm, pSegcsr);
          }
        }
      }
    }

    if( bFound==0 ){
      rc = sqlite3Fts3SegReaderCursor(
          p, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, isPrefix, 0, pSegcsr
      );
      pSegcsr->bLookup = !isPrefix;
    }
  }

  *ppSegcsr = pSegcsr;
  return rc;
}

static void fts3SegReaderCursorFree(Fts3MultiSegReader *pSegcsr){
  sqlite3Fts3SegReaderFinish(pSegcsr);
  sqlite3_free(pSegcsr);
}

/*
** This function retreives the doclist for the specified term (or term
** prefix) from the database. 

  Fts3PhraseToken *pTok,          /* Token to query for */
  int iColumn,                    /* Column to query (or -ve for all columns) */
  int isReqPos,                   /* True to include position lists in output */
  int *pnOut,                     /* OUT: Size of buffer at *ppOut */
  char **ppOut                    /* OUT: Malloced result buffer */
){
  int rc;                         /* Return code */
  Fts3MultiSegReader *pSegcsr;   /* Seg-reader cursor for this term */
  TermSelect tsc;                 /* Context object for fts3TermSelectCb() */
  Fts3SegFilter filter;           /* Segment term filter configuration */

  pSegcsr = pTok->pSegcsr;
  memset(&tsc, 0, sizeof(TermSelect));
  tsc.isReqPos = isReqPos;

  ){
    rc = fts3TermSelectCb(p, (void *)&tsc, 
        pSegcsr->zTerm, pSegcsr->nTerm, pSegcsr->aDoclist, pSegcsr->nDoclist
    );
  }

  if( rc==SQLITE_OK ){
    rc = fts3TermSelectMerge(p, &tsc);
  }
  if( rc==SQLITE_OK ){
    *ppOut = tsc.aaOutput[0];
    *pnOut = tsc.anOutput[0];
  }else{
    int i;
    for(i=0; i<SizeofArray(tsc.aaOutput); i++){

      }
    }
  }

  return nDoc;
}















































































































































































































































































































































































































































































































































































































































































/*
** Advance the cursor to the next row in the %_content table that
** matches the search criteria.  For a MATCH search, this will be
** the next row that matches. For a full-table scan, this will be
** simply the next row in the %_content table.  For a docid lookup,
** this routine simply sets the EOF flag.
**
** Return SQLITE_OK if nothing goes wrong.  SQLITE_OK is returned
** even if we reach end-of-file.  The fts3EofMethod() will be called
** subsequently to determine whether or not an EOF was hit.
*/
static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){
  int rc;

  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
  if( pCsr->eSearch==FTS3_DOCID_SEARCH || pCsr->eSearch==FTS3_FULLSCAN_SEARCH ){



    if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){
      pCsr->isEof = 1;
      rc = sqlite3_reset(pCsr->pStmt);

    }else{
      pCsr->iPrevId = sqlite3_column_int64(pCsr->pStmt, 0);



      rc = SQLITE_OK;

    }

  }else{






    rc = sqlite3Fts3EvalNext((Fts3Cursor *)pCursor);


  }

  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
  return rc;
}

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

static int fts3FilterMethod(
  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 */
){




  int rc;
  char *zSql;                     /* SQL statement used to access %_content */
  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;

  UNUSED_PARAMETER(idxStr);
  UNUSED_PARAMETER(nVal);

  assert( idxNum>=0 && idxNum<=(FTS3_FULLTEXT_SEARCH+p->nColumn) );
  assert( nVal==0 || nVal==1 );
  assert( (nVal==0)==(idxNum==FTS3_FULLSCAN_SEARCH) );
  assert( p->pSegments==0 );

  /* In case the cursor has been used before, clear it now. */
  sqlite3_finalize(pCsr->pStmt);
  sqlite3_free(pCsr->aDoclist);
  sqlite3Fts3ExprFree(pCsr->pExpr);
  memset(&pCursor[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor));

  if( idxStr ){
    pCsr->bDesc = (idxStr[0]=='D');
  }else{
    pCsr->bDesc = p->bDescIdx;
  }
  pCsr->eSearch = (i16)idxNum;

  if( idxNum!=FTS3_DOCID_SEARCH && idxNum!=FTS3_FULLSCAN_SEARCH ){
    int iCol = idxNum-FTS3_FULLTEXT_SEARCH;
    const char *zQuery = (const char *)sqlite3_value_text(apVal[0]);

    if( zQuery==0 && sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
      return SQLITE_NOMEM;
    }

    rc = sqlite3Fts3ExprParse(p->pTokenizer, p->azColumn, p->nColumn, 
        iCol, zQuery, -1, &pCsr->pExpr
    );
    if( rc!=SQLITE_OK ){
      if( rc==SQLITE_ERROR ){
        static const char *zErr = "malformed MATCH expression: [%s]";
        p->base.zErrMsg = sqlite3_mprintf(zErr, zQuery);

      }
      return rc;
    }

    rc = sqlite3Fts3ReadLock(p);
    if( rc!=SQLITE_OK ) return rc;

    rc = sqlite3Fts3EvalStart(pCsr, pCsr->pExpr, 1);

    sqlite3Fts3SegmentsClose(p);
    if( rc!=SQLITE_OK ) return rc;
    pCsr->pNextId = pCsr->aDoclist;
    pCsr->iPrevId = 0;
  }

  /* Compile a SELECT statement for this cursor. For a full-table-scan, the
  ** statement loops through all rows of the %_content table. For a
  ** full-text query or docid lookup, the statement retrieves a single
  ** row by docid.
  */
  if( idxNum==FTS3_FULLSCAN_SEARCH ){
    const char *zSort = (pCsr->bDesc ? "DESC" : "ASC");
    const char *zTmpl = "SELECT %s FROM %Q.'%q_content' AS x ORDER BY docid %s";
    zSql = sqlite3_mprintf(zTmpl, p->zReadExprlist, p->zDb, p->zName, zSort);
  }else{
    const char *zTmpl = "SELECT %s FROM %Q.'%q_content' AS x WHERE docid = ?";
    zSql = sqlite3_mprintf(zTmpl, p->zReadExprlist, p->zDb, p->zName);

  }
  if( !zSql ) return SQLITE_NOMEM;


  rc = sqlite3_prepare_v2(p->db, zSql, -1, &pCsr->pStmt, 0);
  sqlite3_free(zSql);
  if( rc!=SQLITE_OK ) return rc;

  if( idxNum==FTS3_DOCID_SEARCH ){
    rc = sqlite3_bind_value(pCsr->pStmt, 1, apVal[0]);




    if( rc!=SQLITE_OK ) return rc;





  }








  return fts3NextMethod(pCursor);
}

/* 
** 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 fts3EofMethod(sqlite3_vtab_cursor *pCursor){
  return ((Fts3Cursor *)pCursor)->isEof;
}

/* 
** This is the xRowid method. The SQLite core calls this routine to
** retrieve the rowid for the current row of the result set. fts3
** exposes %_content.docid as the rowid for the virtual table. The
** rowid should be written to *pRowid.
*/
static int fts3RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;

  *pRowid = pCsr->iPrevId;








  return SQLITE_OK;
}

/* 
** This is the xColumn method, called by SQLite to request a value from
** the row that the supplied cursor currently points to.
*/
static int fts3ColumnMethod(
  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
  sqlite3_context *pContext,      /* Context for sqlite3_result_xxx() calls */
  int iCol                        /* Index of column to read value from */
){
  int rc = SQLITE_OK;             /* Return Code */
  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
  Fts3Table *p = (Fts3Table *)pCursor->pVtab;

  /* The column value supplied by SQLite must be in range. */
  assert( iCol>=0 && iCol<=p->nColumn+1 );

  if( iCol==p->nColumn+1 ){
    /* This call is a request for the "docid" column. Since "docid" is an 
    ** alias for "rowid", use the xRowid() method to obtain the value.
    */


    sqlite3_result_int64(pContext, pCsr->iPrevId);
  }else if( iCol==p->nColumn ){
    /* The extra column whose name is the same as the table.
    ** Return a blob which is a pointer to the cursor.
    */
    sqlite3_result_blob(pContext, &pCsr, sizeof(pCsr), SQLITE_TRANSIENT);

  }else{
    rc = fts3CursorSeek(0, pCsr);
    if( rc==SQLITE_OK ){
      sqlite3_result_value(pContext, sqlite3_column_value(pCsr->pStmt, iCol+1));
    }
  }

  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
  return rc;
}

/* 
** This function is the implementation of the xUpdate callback used by 
** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
** inserted, updated or deleted.

/*
** Implementation of xBegin() method. This is a no-op.
*/
static int fts3BeginMethod(sqlite3_vtab *pVtab){
  UNUSED_PARAMETER(pVtab);
  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
  assert( p->pSegments==0 );
  assert( p->nPendingData==0 );
  assert( p->inTransaction!=1 );
  TESTONLY( p->inTransaction = 1 );
  TESTONLY( p->mxSavepoint = -1; );
  return SQLITE_OK;
}

/*
** Implementation of xCommit() method. This is a no-op. The contents of
** the pending-terms hash-table have already been flushed into the database
** by fts3SyncMethod().
*/
static int fts3CommitMethod(sqlite3_vtab *pVtab){
  UNUSED_PARAMETER(pVtab);
  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
  assert( p->nPendingData==0 );
  assert( p->inTransaction!=0 );
  assert( p->pSegments==0 );
  TESTONLY( p->inTransaction = 0 );
  TESTONLY( p->mxSavepoint = -1; );
  return SQLITE_OK;
}

/*
** Implementation of xRollback(). Discard the contents of the pending-terms
** hash-table. Any changes made to the database are reverted by SQLite.
*/
static int fts3RollbackMethod(sqlite3_vtab *pVtab){
  Fts3Table *p = (Fts3Table*)pVtab;
  sqlite3Fts3PendingTermsClear(p);
  assert( p->inTransaction!=0 );
  TESTONLY( p->inTransaction = 0 );
  TESTONLY( p->mxSavepoint = -1; );
  return SQLITE_OK;
}































/*
** When called, *ppPoslist must point to the byte immediately following the
** end of a position-list. i.e. ( (*ppPoslist)[-1]==POS_END ). This function
** moves *ppPoslist so that it instead points to the first byte of the
** same position list.
*/
static void fts3ReversePoslist(char *pStart, char **ppPoslist){
  char *p = &(*ppPoslist)[-2];
  char c;

  while( p>pStart && (c=*p--)==0 );
  while( p>pStart && (*p & 0x80) | c ){ 
    c = *p--; 
  }
  if( p>pStart ){ p = &p[2]; }
  while( *p++&0x80 );
  *ppPoslist = p;
}











































































/*
** Helper function used by the implementation of the overloaded snippet(),
** offsets() and optimize() SQL functions.
**
** If the value passed as the third argument is a blob of size
** sizeof(Fts3Cursor*), then the blob contents are copied to the 
** output variable *ppCsr and SQLITE_OK is returned. Otherwise, an error

    "ALTER TABLE %Q.'%q_segdir'   RENAME TO '%q_segdir';",
    p->zDb, p->zName, zName
  );
  return rc;
}

static int fts3SavepointMethod(sqlite3_vtab *pVtab, int iSavepoint){

  UNUSED_PARAMETER(iSavepoint);
  assert( ((Fts3Table *)pVtab)->inTransaction );
  assert( ((Fts3Table *)pVtab)->mxSavepoint < iSavepoint );
  TESTONLY( ((Fts3Table *)pVtab)->mxSavepoint = iSavepoint );
  return fts3SyncMethod(pVtab);
}
static int fts3ReleaseMethod(sqlite3_vtab *pVtab, int iSavepoint){
  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
  UNUSED_PARAMETER(iSavepoint);
  UNUSED_PARAMETER(pVtab);
  assert( p->inTransaction );
  assert( p->mxSavepoint >= iSavepoint );

  const sqlite3_api_routines *pApi
){
  SQLITE_EXTENSION_INIT2(pApi)
  return sqlite3Fts3Init(db);
}
#endif


/*
** Allocate an Fts3MultiSegReader for each token in the expression headed
** by pExpr. 
**
** An Fts3SegReader object is a cursor that can seek or scan a range of
** entries within a single segment b-tree. An Fts3MultiSegReader uses multiple
** Fts3SegReader objects internally to provide an interface to seek or scan
** within the union of all segments of a b-tree. Hence the name.
**
** If the allocated Fts3MultiSegReader just seeks to a single entry in a
** segment b-tree (if the term is not a prefix or it is a prefix for which
** there exists prefix b-tree of the right length) then it may be traversed
** and merged incrementally. Otherwise, it has to be merged into an in-memory 
** doclist and then traversed.
*/
static void fts3EvalAllocateReaders(
  Fts3Cursor *pCsr, 
  Fts3Expr *pExpr, 
  int *pnToken,                   /* OUT: Total number of tokens in phrase. */
  int *pnOr,                      /* OUT: Total number of OR nodes in expr. */
  int *pRc
){
  if( pExpr && SQLITE_OK==*pRc ){
    if( pExpr->eType==FTSQUERY_PHRASE ){
      int i;
      int nToken = pExpr->pPhrase->nToken;
      *pnToken += nToken;
      for(i=0; i<nToken; i++){
        Fts3PhraseToken *pToken = &pExpr->pPhrase->aToken[i];
        int rc = sqlite3Fts3TermSegReaderCursor(pCsr, 
            pToken->z, pToken->n, pToken->isPrefix, &pToken->pSegcsr
        );
        if( rc!=SQLITE_OK ){
          *pRc = rc;
          return;
        }
      }
    }else{
      *pnOr += (pExpr->eType==FTSQUERY_OR);
      fts3EvalAllocateReaders(pCsr, pExpr->pLeft, pnToken, pnOr, pRc);
      fts3EvalAllocateReaders(pCsr, pExpr->pRight, pnToken, pnOr, pRc);
    }
  }
}

static int fts3EvalPhraseLoad(
  Fts3Cursor *pCsr, 
  Fts3Phrase *p
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int iToken;
  int rc = SQLITE_OK;

  char *aDoclist = 0;
  int nDoclist = 0;
  int iPrev = -1;

  for(iToken=0; rc==SQLITE_OK && iToken<p->nToken; iToken++){
    Fts3PhraseToken *pToken = &p->aToken[iToken];
    assert( pToken->pSegcsr || pToken->pDeferred );

    if( pToken->pDeferred==0 ){
      int nThis = 0;
      char *pThis = 0;
      rc = fts3TermSelect(pTab, pToken, p->iColumn, 1, &nThis, &pThis);
      if( rc==SQLITE_OK ){
        if( pThis==0 ){
          sqlite3_free(aDoclist);
          aDoclist = 0;
          nDoclist = 0;
          break;
        }else if( aDoclist==0 ){
          aDoclist = pThis;
          nDoclist = nThis;
        }else{
          assert( iPrev>=0 );
          fts3DoclistPhraseMerge(pTab->bDescIdx,
              iToken-iPrev, aDoclist, nDoclist, pThis, &nThis
          );
          sqlite3_free(aDoclist);
          aDoclist = pThis;
          nDoclist = nThis;
        }
        iPrev = iToken;
      }
    }
  }

  if( rc==SQLITE_OK ){
    p->doclist.aAll = aDoclist;
    p->doclist.nAll = nDoclist;
  }else{
    sqlite3_free(aDoclist);
  }
  return rc;
}

static int fts3EvalDeferredPhrase(Fts3Cursor *pCsr, Fts3Phrase *pPhrase){
  int iToken;
  int rc = SQLITE_OK;

  int nMaxUndeferred = -1;
  char *aPoslist = 0;
  int nPoslist = 0;
  int iPrev = -1;

  assert( pPhrase->doclist.bFreeList==0 );

  for(iToken=0; rc==SQLITE_OK && iToken<pPhrase->nToken; iToken++){
    Fts3PhraseToken *pToken = &pPhrase->aToken[iToken];
    Fts3DeferredToken *pDeferred = pToken->pDeferred;

    if( pDeferred ){
      char *pList;
      int nList;
      rc = sqlite3Fts3DeferredTokenList(pDeferred, &pList, &nList);
      if( rc!=SQLITE_OK ) return rc;

      if( pList==0 ){
        sqlite3_free(aPoslist);
        pPhrase->doclist.pList = 0;
        pPhrase->doclist.nList = 0;
        return SQLITE_OK;

      }else if( aPoslist==0 ){
        aPoslist = pList;
        nPoslist = nList;

      }else{
        assert( iPrev>=0 );

        char *aOut = pList;
        char *p1 = aPoslist;
        char *p2 = aOut;

        fts3PoslistPhraseMerge(&aOut, iToken-iPrev, 0, 1, &p1, &p2);
        sqlite3_free(aPoslist);
        aPoslist = pList;
        nPoslist = aOut - aPoslist;
        if( nPoslist==0 ){
          sqlite3_free(aPoslist);
          pPhrase->doclist.pList = 0;
          pPhrase->doclist.nList = 0;
          return SQLITE_OK;
        }
      }
      iPrev = iToken;
    }else{
      nMaxUndeferred = iToken;
    }
  }

  if( iPrev>=0 ){
    if( nMaxUndeferred<0 ){
      pPhrase->doclist.pList = aPoslist;
      pPhrase->doclist.nList = nPoslist;
      pPhrase->doclist.iDocid = pCsr->iPrevId;
      pPhrase->doclist.bFreeList = 1;
    }else{
      int nDistance;
      char *p1;
      char *p2;
      char *aOut;

      if( nMaxUndeferred>iPrev ){
        p1 = aPoslist;
        p2 = pPhrase->doclist.pList;
        nDistance = nMaxUndeferred - iPrev;
      }else{
        p1 = pPhrase->doclist.pList;
        p2 = aPoslist;
        nDistance = iPrev - nMaxUndeferred;
      }

      aOut = (char *)sqlite3_malloc(nPoslist+8);
      if( !aOut ){
        sqlite3_free(aPoslist);
        return SQLITE_NOMEM;
      }
      
      pPhrase->doclist.pList = aOut;
      if( fts3PoslistPhraseMerge(&aOut, nDistance, 0, 1, &p1, &p2) ){
        pPhrase->doclist.bFreeList = 1;
        pPhrase->doclist.nList = (aOut - pPhrase->doclist.pList);
      }else{
        sqlite3_free(aOut);
        pPhrase->doclist.pList = 0;
        pPhrase->doclist.nList = 0;
      }
      sqlite3_free(aPoslist);
    }
  }

  return SQLITE_OK;
}

/*
** This function is called for each Fts3Phrase in a full-text query 
** expression to initialize the mechanism for returning rows. Once this
** function has been called successfully on an Fts3Phrase, it may be
** used with fts3EvalPhraseNext() to iterate through the matching docids.
*/
static int fts3EvalPhraseStart(Fts3Cursor *pCsr, int bOptOk, Fts3Phrase *p){
  int rc;
  Fts3PhraseToken *pFirst = &p->aToken[0];
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;

  assert( p->doclist.aAll==0 );
  if( pCsr->bDesc==pTab->bDescIdx && bOptOk==1 && p->nToken==1 
   && pFirst->pSegcsr && pFirst->pSegcsr->bLookup 
  ){
    /* Use the incremental approach. */
    int iCol = (p->iColumn >= pTab->nColumn ? -1 : p->iColumn);
    rc = sqlite3Fts3MsrIncrStart(
        pTab, pFirst->pSegcsr, iCol, pFirst->z, pFirst->n);
    p->bIncr = 1;

  }else{
    /* Load the full doclist for the phrase into memory. */
    rc = fts3EvalPhraseLoad(pCsr, p);
    p->bIncr = 0;
  }

  assert( rc!=SQLITE_OK || p->nToken<1 || p->aToken[0].pSegcsr==0 || p->bIncr );
  return rc;
}

/*
** This function is used to iterate backwards (from the end to start) 
** through doclists.
*/
void sqlite3Fts3DoclistPrev(
  int bDescIdx,                   /* True if the doclist is desc */
  char *aDoclist,                 /* Pointer to entire doclist */
  int nDoclist,                   /* Length of aDoclist in bytes */
  char **ppIter,                  /* IN/OUT: Iterator pointer */
  sqlite3_int64 *piDocid,         /* IN/OUT: Docid pointer */
  int *pnList,                    /* IN/OUT: List length pointer */
  u8 *pbEof                       /* OUT: End-of-file flag */
){
  char *p = *ppIter;

  assert( nDoclist>0 );
  assert( *pbEof==0 );
  assert( p || *piDocid==0 );
  assert( !p || (p>aDoclist && p<&aDoclist[nDoclist]) );

  if( p==0 ){
    sqlite3_int64 iDocid = 0;
    char *pNext = 0;
    char *pDocid = aDoclist;
    char *pEnd = &aDoclist[nDoclist];
    int iMul = 1;

    while( pDocid<pEnd ){
      sqlite3_int64 iDelta;
      pDocid += sqlite3Fts3GetVarint(pDocid, &iDelta);
      iDocid += (iMul * iDelta);
      pNext = pDocid;
      fts3PoslistCopy(0, &pDocid);
      while( pDocid<pEnd && *pDocid==0 ) pDocid++;
      iMul = (bDescIdx ? -1 : 1);
    }

    *pnList = pEnd - pNext;
    *ppIter = pNext;
    *piDocid = iDocid;
  }else{
    int iMul = (bDescIdx ? -1 : 1);
    sqlite3_int64 iDelta;
    fts3GetReverseVarint(&p, aDoclist, &iDelta);
    *piDocid -= (iMul * iDelta);

    if( p==aDoclist ){
      *pbEof = 1;
    }else{
      char *pSave = p;
      fts3ReversePoslist(aDoclist, &p);
      *pnList = (pSave - p);
    }
    *ppIter = p;
  }
}

/*
** Attempt to move the phrase iterator to point to the next matching docid. 
** If an error occurs, return an SQLite error code. Otherwise, return 
** SQLITE_OK.
**
** If there is no "next" entry and no error occurs, then *pbEof is set to
** 1 before returning. Otherwise, if no error occurs and the iterator is
** successfully advanced, *pbEof is set to 0.
*/
static int fts3EvalPhraseNext(
  Fts3Cursor *pCsr, 
  Fts3Phrase *p, 
  u8 *pbEof
){
  int rc = SQLITE_OK;
  Fts3Doclist *pDL = &p->doclist;
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;

  if( p->bIncr ){
    assert( p->nToken==1 );
    assert( pDL->pNextDocid==0 );
    rc = sqlite3Fts3MsrIncrNext(pTab, p->aToken[0].pSegcsr, 
        &pDL->iDocid, &pDL->pList, &pDL->nList
    );
    if( rc==SQLITE_OK && !pDL->pList ){
      *pbEof = 1;
    }
  }else if( pCsr->bDesc!=pTab->bDescIdx && pDL->nAll ){
    sqlite3Fts3DoclistPrev(pTab->bDescIdx, pDL->aAll, pDL->nAll, 
        &pDL->pNextDocid, &pDL->iDocid, &pDL->nList, pbEof
    );
    pDL->pList = pDL->pNextDocid;
  }else{
    char *pIter;                            /* Used to iterate through aAll */
    char *pEnd = &pDL->aAll[pDL->nAll];     /* 1 byte past end of aAll */
    if( pDL->pNextDocid ){
      pIter = pDL->pNextDocid;
    }else{
      pIter = pDL->aAll;
    }

    if( pIter>=pEnd ){
      /* We have already reached the end of this doclist. EOF. */
      *pbEof = 1;
    }else{
      sqlite3_int64 iDelta;
      pIter += sqlite3Fts3GetVarint(pIter, &iDelta);
      if( pTab->bDescIdx==0 || pDL->pNextDocid==0 ){
        pDL->iDocid += iDelta;
      }else{
        pDL->iDocid -= iDelta;
      }
      pDL->pList = pIter;
      fts3PoslistCopy(0, &pIter);
      pDL->nList = (pIter - pDL->pList);

      /* pIter now points just past the 0x00 that terminates the position-
      ** list for document pDL->iDocid. However, if this position-list was
      ** edited in place by fts3EvalNearTrim2(), then pIter may not actually
      ** point to the start of the next docid value. The following line deals
      ** with this case by advancing pIter past the zero-padding added by
      ** fts3EvalNearTrim2().  */
      while( pIter<pEnd && *pIter==0 ) pIter++;

      pDL->pNextDocid = pIter;
      assert( *pIter || pIter>=&pDL->aAll[pDL->nAll] );
      *pbEof = 0;
    }
  }

  return rc;
}

static void fts3EvalStartReaders(
  Fts3Cursor *pCsr, 
  Fts3Expr *pExpr, 
  int bOptOk,
  int *pRc
){
  if( pExpr && SQLITE_OK==*pRc ){
    if( pExpr->eType==FTSQUERY_PHRASE ){
      int i;
      int nToken = pExpr->pPhrase->nToken;
      for(i=0; i<nToken; i++){
        if( pExpr->pPhrase->aToken[i].pDeferred==0 ) break;
      }
      pExpr->bDeferred = (i==nToken);
      *pRc = fts3EvalPhraseStart(pCsr, bOptOk, pExpr->pPhrase);
    }else{
      fts3EvalStartReaders(pCsr, pExpr->pLeft, bOptOk, pRc);
      fts3EvalStartReaders(pCsr, pExpr->pRight, bOptOk, pRc);
      pExpr->bDeferred = (pExpr->pLeft->bDeferred && pExpr->pRight->bDeferred);
    }
  }
}


typedef struct Fts3TokenAndCost Fts3TokenAndCost;
struct Fts3TokenAndCost {
  Fts3PhraseToken *pToken;
  Fts3Expr *pRoot;
  int nOvfl;
  int iCol;
};

static void fts3EvalTokenCosts(
  Fts3Cursor *pCsr, 
  Fts3Expr *pRoot, 
  Fts3Expr *pExpr, 
  Fts3TokenAndCost **ppTC,
  Fts3Expr ***ppOr,
  int *pRc
){
  if( *pRc==SQLITE_OK && pExpr ){
    if( pExpr->eType==FTSQUERY_PHRASE ){
      Fts3Phrase *pPhrase = pExpr->pPhrase;
      int i;
      for(i=0; *pRc==SQLITE_OK && i<pPhrase->nToken; i++){
        Fts3TokenAndCost *pTC = (*ppTC)++;
        pTC->pRoot = pRoot;
        pTC->pToken = &pPhrase->aToken[i];
        pTC->iCol = pPhrase->iColumn;
        *pRc = sqlite3Fts3MsrOvfl(pCsr, pTC->pToken->pSegcsr, &pTC->nOvfl);
      }
    }else if( pExpr->eType!=FTSQUERY_NOT ){
      if( pExpr->eType==FTSQUERY_OR ){
        pRoot = pExpr->pLeft;
        **ppOr = pRoot;
        (*ppOr)++;
      }
      fts3EvalTokenCosts(pCsr, pRoot, pExpr->pLeft, ppTC, ppOr, pRc);
      if( pExpr->eType==FTSQUERY_OR ){
        pRoot = pExpr->pRight;
        **ppOr = pRoot;
        (*ppOr)++;
      }
      fts3EvalTokenCosts(pCsr, pRoot, pExpr->pRight, ppTC, ppOr, pRc);
    }
  }
}

static int fts3EvalAverageDocsize(Fts3Cursor *pCsr, int *pnPage){
  if( pCsr->nRowAvg==0 ){
    /* The average document size, which is required to calculate the cost
     ** of each doclist, has not yet been determined. Read the required 
     ** data from the %_stat table to calculate it.
     **
     ** Entry 0 of the %_stat table is a blob containing (nCol+1) FTS3 
     ** varints, where nCol is the number of columns in the FTS3 table.
     ** The first varint is the number of documents currently stored in
     ** the table. The following nCol varints contain the total amount of
     ** data stored in all rows of each column of the table, from left
     ** to right.
     */
    int rc;
    Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
    sqlite3_stmt *pStmt;
    sqlite3_int64 nDoc = 0;
    sqlite3_int64 nByte = 0;
    const char *pEnd;
    const char *a;

    rc = sqlite3Fts3SelectDoctotal(p, &pStmt);
    if( rc!=SQLITE_OK ) return rc;
    a = sqlite3_column_blob(pStmt, 0);
    assert( a );

    pEnd = &a[sqlite3_column_bytes(pStmt, 0)];
    a += sqlite3Fts3GetVarint(a, &nDoc);
    while( a<pEnd ){
      a += sqlite3Fts3GetVarint(a, &nByte);
    }
    if( nDoc==0 || nByte==0 ){
      sqlite3_reset(pStmt);
      return SQLITE_CORRUPT_VTAB;
    }

    pCsr->nDoc = nDoc;
    pCsr->nRowAvg = (int)(((nByte / nDoc) + p->nPgsz) / p->nPgsz);
    assert( pCsr->nRowAvg>0 ); 
    rc = sqlite3_reset(pStmt);
    if( rc!=SQLITE_OK ) return rc;
  }

  *pnPage = pCsr->nRowAvg;
  return SQLITE_OK;
}

static int fts3EvalSelectDeferred(
  Fts3Cursor *pCsr,
  Fts3Expr *pRoot,
  Fts3TokenAndCost *aTC,
  int nTC
){
  int nDocSize = 0;
  int nDocEst = 0;
  int rc = SQLITE_OK;
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int ii;

  int nOvfl = 0;
  int nTerm = 0;

  for(ii=0; ii<nTC; ii++){
    if( aTC[ii].pRoot==pRoot ){
      nOvfl += aTC[ii].nOvfl;
      nTerm++;
    }
  }
  if( nOvfl==0 || nTerm<2 ) return SQLITE_OK;

  rc = fts3EvalAverageDocsize(pCsr, &nDocSize);

  for(ii=0; ii<nTerm && rc==SQLITE_OK; ii++){
    int jj;
    Fts3TokenAndCost *pTC = 0;

    for(jj=0; jj<nTC; jj++){
      if( aTC[jj].pToken && aTC[jj].pRoot==pRoot 
       && (!pTC || aTC[jj].nOvfl<pTC->nOvfl) 
      ){
        pTC = &aTC[jj];
      }
    }
    assert( pTC );

    /* At this point pTC points to the cheapest remaining token. */
    if( ii==0 ){
      if( pTC->nOvfl ){
        nDocEst = (pTC->nOvfl * pTab->nPgsz + pTab->nPgsz) / 10;
      }else{
        /* TODO: Fix this so that the doclist need not be read twice. */
        Fts3PhraseToken *pToken = pTC->pToken;
        int nList = 0;
        char *pList = 0;
        rc = fts3TermSelect(pTab, pToken, pTC->iCol, 1, &nList, &pList);
        if( rc==SQLITE_OK ){
          nDocEst = fts3DoclistCountDocids(1, pList, nList);
        }
        sqlite3_free(pList);
        if( rc==SQLITE_OK ){
          rc = sqlite3Fts3TermSegReaderCursor(pCsr, 
              pToken->z, pToken->n, pToken->isPrefix, &pToken->pSegcsr
          );
        }
      }
    }else{
      if( pTC->nOvfl>=(nDocEst*nDocSize) ){
        Fts3PhraseToken *pToken = pTC->pToken;
        rc = sqlite3Fts3DeferToken(pCsr, pToken, pTC->iCol);
        fts3SegReaderCursorFree(pToken->pSegcsr);
        pToken->pSegcsr = 0;
      }
      nDocEst = 1 + (nDocEst/4);
    }
    pTC->pToken = 0;
  }

  return rc;
}

int sqlite3Fts3EvalStart(Fts3Cursor *pCsr, Fts3Expr *pExpr, int bOptOk){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int rc = SQLITE_OK;
  int nToken = 0;
  int nOr = 0;

  /* Allocate a MultiSegReader for each token in the expression. */
  fts3EvalAllocateReaders(pCsr, pExpr, &nToken, &nOr, &rc);

  /* Call fts3EvalPhraseStart() on all phrases in the expression. TODO:
  ** This call will eventually also be responsible for determining which
  ** tokens are 'deferred' until the document text is loaded into memory.
  **
  ** Each token in each phrase is dealt with using one of the following
  ** three strategies:
  **
  **   1. Entire doclist loaded into memory as part of the
  **      fts3EvalStartReaders() call.
  **
  **   2. Doclist loaded into memory incrementally, as part of each
  **      sqlite3Fts3EvalNext() call.
  **
  **   3. Token doclist is never loaded. Instead, documents are loaded into
  **      memory and scanned for the token as part of the sqlite3Fts3EvalNext()
  **      call. This is known as a "deferred" token.
  */

  /* If bOptOk is true, check if there are any tokens that should be deferred.
  */
  if( rc==SQLITE_OK && bOptOk && nToken>1 && pTab->bHasStat ){
    Fts3TokenAndCost *aTC;
    Fts3Expr **apOr;
    aTC = (Fts3TokenAndCost *)sqlite3_malloc(
        sizeof(Fts3TokenAndCost) * nToken
      + sizeof(Fts3Expr *) * nOr * 2
    );
    apOr = (Fts3Expr **)&aTC[nToken];

    if( !aTC ){
      rc = SQLITE_NOMEM;
    }else{
      int ii;
      Fts3TokenAndCost *pTC = aTC;
      Fts3Expr **ppOr = apOr;

      fts3EvalTokenCosts(pCsr, 0, pExpr, &pTC, &ppOr, &rc);
      nToken = pTC-aTC;
      nOr = ppOr-apOr;

      if( rc==SQLITE_OK ){
        rc = fts3EvalSelectDeferred(pCsr, 0, aTC, nToken);
        for(ii=0; rc==SQLITE_OK && ii<nOr; ii++){
          rc = fts3EvalSelectDeferred(pCsr, apOr[ii], aTC, nToken);
        }
      }

      sqlite3_free(aTC);
    }
  }

  fts3EvalStartReaders(pCsr, pExpr, bOptOk, &rc);
  return rc;
}

static void fts3EvalZeroPoslist(Fts3Phrase *pPhrase){
  if( pPhrase->doclist.bFreeList ){
    sqlite3_free(pPhrase->doclist.pList);
  }
  pPhrase->doclist.pList = 0;
  pPhrase->doclist.nList = 0;
  pPhrase->doclist.bFreeList = 0;
}

static int fts3EvalNearTrim2(
  int nNear,
  char *aTmp,                     /* Temporary space to use */
  char **paPoslist,               /* IN/OUT: Position list */
  int *pnToken,                   /* IN/OUT: Tokens in phrase of *paPoslist */
  Fts3Phrase *pPhrase             /* The phrase object to trim the doclist of */
){
  int nParam1 = nNear + pPhrase->nToken;
  int nParam2 = nNear + *pnToken;
  int nNew;
  char *p2; 
  char *pOut; 
  int res;

  assert( pPhrase->doclist.pList );

  p2 = pOut = pPhrase->doclist.pList;
  res = fts3PoslistNearMerge(
    &pOut, aTmp, nParam1, nParam2, paPoslist, &p2
  );
  if( res ){
    nNew = (pOut - pPhrase->doclist.pList) - 1;
    assert( pPhrase->doclist.pList[nNew]=='\0' );
    assert( nNew<=pPhrase->doclist.nList && nNew>0 );
    memset(&pPhrase->doclist.pList[nNew], 0, pPhrase->doclist.nList - nNew);
    pPhrase->doclist.nList = nNew;
    *paPoslist = pPhrase->doclist.pList;
    *pnToken = pPhrase->nToken;
  }

  return res;
}

static int fts3EvalNearTest(Fts3Expr *pExpr, int *pRc){
  int res = 1;

  /* The following block runs if pExpr is the root of a NEAR query.
  ** For example, the query:
  **
  **         "w" NEAR "x" NEAR "y" NEAR "z"
  **
  ** which is represented in tree form as:
  **
  **                               |
  **                          +--NEAR--+      <-- root of NEAR query
  **                          |        |
  **                     +--NEAR--+   "z"
  **                     |        |
  **                +--NEAR--+   "y"
  **                |        |
  **               "w"      "x"
  **
  ** The right-hand child of a NEAR node is always a phrase. The 
  ** left-hand child may be either a phrase or a NEAR node. There are
  ** no exceptions to this.
  */
  if( *pRc==SQLITE_OK 
   && pExpr->eType==FTSQUERY_NEAR 
   && pExpr->bEof==0
   && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
  ){
    Fts3Expr *p; 
    int nTmp = 0;                 /* Bytes of temp space */
    char *aTmp;                   /* Temp space for PoslistNearMerge() */

    /* Allocate temporary working space. */
    for(p=pExpr; p->pLeft; p=p->pLeft){
      nTmp += p->pRight->pPhrase->doclist.nList;
    }
    nTmp += p->pPhrase->doclist.nList;
    aTmp = sqlite3_malloc(nTmp*2);
    if( !aTmp ){
      *pRc = SQLITE_NOMEM;
      res = 0;
    }else{
      char *aPoslist = p->pPhrase->doclist.pList;
      int nToken = p->pPhrase->nToken;

      for(p=p->pParent;res && p && p->eType==FTSQUERY_NEAR; p=p->pParent){
        Fts3Phrase *pPhrase = p->pRight->pPhrase;
        int nNear = p->nNear;
        res = fts3EvalNearTrim2(nNear, aTmp, &aPoslist, &nToken, pPhrase);
      }
  
      aPoslist = pExpr->pRight->pPhrase->doclist.pList;
      nToken = pExpr->pRight->pPhrase->nToken;
      for(p=pExpr->pLeft; p && res; p=p->pLeft){
        int nNear = p->pParent->nNear;
        Fts3Phrase *pPhrase = (
            p->eType==FTSQUERY_NEAR ? p->pRight->pPhrase : p->pPhrase
        );
        res = fts3EvalNearTrim2(nNear, aTmp, &aPoslist, &nToken, pPhrase);
      }
    }

    sqlite3_free(aTmp);
  }

  return res;
}

/*
** This macro is used by the fts3EvalNext() function. The two arguments are
** 64-bit docid values. If the current query is "ORDER BY docid ASC", then
** the macro returns (i1 - i2). Or if it is "ORDER BY docid DESC", then
** it returns (i2 - i1). This allows the same code to be used for merging
** doclists in ascending or descending order.
*/
#define DOCID_CMP(i1, i2) ((pCsr->bDesc?-1:1) * (i1-i2))

static void fts3EvalNext(
  Fts3Cursor *pCsr, 
  Fts3Expr *pExpr, 
  int *pRc
){
  if( *pRc==SQLITE_OK ){
    assert( pExpr->bEof==0 );
    pExpr->bStart = 1;

    switch( pExpr->eType ){
      case FTSQUERY_NEAR:
      case FTSQUERY_AND: {
        Fts3Expr *pLeft = pExpr->pLeft;
        Fts3Expr *pRight = pExpr->pRight;
        assert( !pLeft->bDeferred || !pRight->bDeferred );
        if( pLeft->bDeferred ){
          fts3EvalNext(pCsr, pRight, pRc);
          pExpr->iDocid = pRight->iDocid;
          pExpr->bEof = pRight->bEof;
        }else if( pRight->bDeferred ){
          fts3EvalNext(pCsr, pLeft, pRc);
          pExpr->iDocid = pLeft->iDocid;
          pExpr->bEof = pLeft->bEof;
        }else{
          fts3EvalNext(pCsr, pLeft, pRc);
          fts3EvalNext(pCsr, pRight, pRc);

          while( !pLeft->bEof && !pRight->bEof && *pRc==SQLITE_OK ){
            sqlite3_int64 iDiff = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
            if( iDiff==0 ) break;
            if( iDiff<0 ){
              fts3EvalNext(pCsr, pLeft, pRc);
            }else{
              fts3EvalNext(pCsr, pRight, pRc);
            }
          }

          pExpr->iDocid = pLeft->iDocid;
          pExpr->bEof = (pLeft->bEof || pRight->bEof);
        }
        break;
      }
  
      case FTSQUERY_OR: {
        Fts3Expr *pLeft = pExpr->pLeft;
        Fts3Expr *pRight = pExpr->pRight;
        sqlite3_int64 iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid);

        assert( pLeft->bStart || pLeft->iDocid==pRight->iDocid );
        assert( pRight->bStart || pLeft->iDocid==pRight->iDocid );

        if( pRight->bEof || (pLeft->bEof==0 && iCmp<0) ){
          fts3EvalNext(pCsr, pLeft, pRc);
        }else if( pLeft->bEof || (pRight->bEof==0 && iCmp>0) ){
          fts3EvalNext(pCsr, pRight, pRc);
        }else{
          fts3EvalNext(pCsr, pLeft, pRc);
          fts3EvalNext(pCsr, pRight, pRc);
        }

        pExpr->bEof = (pLeft->bEof && pRight->bEof);
        iCmp = DOCID_CMP(pLeft->iDocid, pRight->iDocid);
        if( pRight->bEof || (pLeft->bEof==0 &&  iCmp<0) ){
          pExpr->iDocid = pLeft->iDocid;
        }else{
          pExpr->iDocid = pRight->iDocid;
        }

        break;
      }

      case FTSQUERY_NOT: {
        Fts3Expr *pLeft = pExpr->pLeft;
        Fts3Expr *pRight = pExpr->pRight;

        if( pRight->bStart==0 ){
          fts3EvalNext(pCsr, pRight, pRc);
          assert( *pRc!=SQLITE_OK || pRight->bStart );
        }

        fts3EvalNext(pCsr, pLeft, pRc);
        if( pLeft->bEof==0 ){
          while( !*pRc 
              && !pRight->bEof 
              && DOCID_CMP(pLeft->iDocid, pRight->iDocid)>0 
          ){
            fts3EvalNext(pCsr, pRight, pRc);
          }
        }
        pExpr->iDocid = pLeft->iDocid;
        pExpr->bEof = pLeft->bEof;
        break;
      }

      default: {
        Fts3Phrase *pPhrase = pExpr->pPhrase;
        fts3EvalZeroPoslist(pPhrase);
        *pRc = fts3EvalPhraseNext(pCsr, pPhrase, &pExpr->bEof);
        pExpr->iDocid = pPhrase->doclist.iDocid;
        break;
      }
    }
  }
}

static int fts3EvalDeferredTest(Fts3Cursor *pCsr, Fts3Expr *pExpr, int *pRc){
  int bHit = 1;
  if( *pRc==SQLITE_OK ){
    switch( pExpr->eType ){
      case FTSQUERY_NEAR:
      case FTSQUERY_AND:
        bHit = (
            fts3EvalDeferredTest(pCsr, pExpr->pLeft, pRc)
         && fts3EvalDeferredTest(pCsr, pExpr->pRight, pRc)
         && fts3EvalNearTest(pExpr, pRc)
        );

        /* If the NEAR expression does not match any rows, zero the doclist for 
        ** all phrases involved in the NEAR. This is because the snippet(),
        ** offsets() and matchinfo() functions are not supposed to recognize 
        ** any instances of phrases that are part of unmatched NEAR queries. 
        ** For example if this expression:
        **
        **    ... MATCH 'a OR (b NEAR c)'
        **
        ** is matched against a row containing:
        **
        **        'a b d e'
        **
        ** then any snippet() should ony highlight the "a" term, not the "b"
        ** (as "b" is part of a non-matching NEAR clause).
        */
        if( bHit==0 
         && pExpr->eType==FTSQUERY_NEAR 
         && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
        ){
          Fts3Expr *p;
          for(p=pExpr; p->pPhrase==0; p=p->pLeft){
            if( p->pRight->iDocid==pCsr->iPrevId ){
              fts3EvalZeroPoslist(p->pRight->pPhrase);
            }
          }
          if( p->iDocid==pCsr->iPrevId ){
            fts3EvalZeroPoslist(p->pPhrase);
          }
        }

        break;

      case FTSQUERY_OR: {
        int bHit1 = fts3EvalDeferredTest(pCsr, pExpr->pLeft, pRc);
        int bHit2 = fts3EvalDeferredTest(pCsr, pExpr->pRight, pRc);
        bHit = bHit1 || bHit2;
        break;
      }

      case FTSQUERY_NOT:
        bHit = (
            fts3EvalDeferredTest(pCsr, pExpr->pLeft, pRc)
         && !fts3EvalDeferredTest(pCsr, pExpr->pRight, pRc)
        );
        break;

      default: {
        if( pCsr->pDeferred 
         && (pExpr->iDocid==pCsr->iPrevId || pExpr->bDeferred)
        ){
          Fts3Phrase *pPhrase = pExpr->pPhrase;
          assert( pExpr->bDeferred || pPhrase->doclist.bFreeList==0 );
          if( pExpr->bDeferred ){
            fts3EvalZeroPoslist(pPhrase);
          }
          *pRc = fts3EvalDeferredPhrase(pCsr, pPhrase);
          bHit = (pPhrase->doclist.pList!=0);
          pExpr->iDocid = pCsr->iPrevId;
        }else{
          bHit = (pExpr->bEof==0 && pExpr->iDocid==pCsr->iPrevId);
        }
        break;
      }
    }
  }
  return bHit;
}

/*
** Return 1 if both of the following are true:
**
**   1. *pRc is SQLITE_OK when this function returns, and
**
**   2. After scanning the current FTS table row for the deferred tokens,
**      it is determined that the row does not match the query.
**
** Or, if no error occurs and it seems the current row does match the FTS
** query, return 0.
*/
static int fts3EvalLoadDeferred(Fts3Cursor *pCsr, int *pRc){
  int rc = *pRc;
  int bMiss = 0;
  if( rc==SQLITE_OK ){
    if( pCsr->pDeferred ){
      rc = fts3CursorSeek(0, pCsr);
      if( rc==SQLITE_OK ){
        rc = sqlite3Fts3CacheDeferredDoclists(pCsr);
      }
    }
    bMiss = (0==fts3EvalDeferredTest(pCsr, pCsr->pExpr, &rc));
    sqlite3Fts3FreeDeferredDoclists(pCsr);
    *pRc = rc;
  }
  return (rc==SQLITE_OK && bMiss);
}

/*
** Advance to the next document that matches the FTS expression in
** Fts3Cursor.pExpr.
*/
int sqlite3Fts3EvalNext(Fts3Cursor *pCsr){
  int rc = SQLITE_OK;             /* Return Code */
  Fts3Expr *pExpr = pCsr->pExpr;
  assert( pCsr->isEof==0 );
  if( pExpr==0 ){
    pCsr->isEof = 1;
  }else{
    do {
      if( pCsr->isRequireSeek==0 ){
        sqlite3_reset(pCsr->pStmt);
      }
      assert( sqlite3_data_count(pCsr->pStmt)==0 );
      fts3EvalNext(pCsr, pExpr, &rc);
      pCsr->isEof = pExpr->bEof;
      pCsr->isRequireSeek = 1;
      pCsr->isMatchinfoNeeded = 1;
      pCsr->iPrevId = pExpr->iDocid;
    }while( pCsr->isEof==0 && fts3EvalLoadDeferred(pCsr, &rc) );
  }
  return rc;
}

/*
** Restart interation for expression pExpr so that the next call to
** sqlite3Fts3EvalNext() visits the first row. Do not allow incremental 
** loading or merging of phrase doclists for this iteration.
**
** If *pRc is other than SQLITE_OK when this function is called, it is
** a no-op. If an error occurs within this function, *pRc is set to an
** SQLite error code before returning.
*/
static void fts3EvalRestart(
  Fts3Cursor *pCsr,
  Fts3Expr *pExpr,
  int *pRc
){
  if( pExpr && *pRc==SQLITE_OK ){
    Fts3Phrase *pPhrase = pExpr->pPhrase;

    if( pPhrase ){
      fts3EvalZeroPoslist(pPhrase);
      if( pPhrase->bIncr ){
        sqlite3Fts3EvalPhraseCleanup(pPhrase);
        memset(&pPhrase->doclist, 0, sizeof(Fts3Doclist));
        *pRc = sqlite3Fts3EvalStart(pCsr, pExpr, 0);
      }else{
        pPhrase->doclist.pNextDocid = 0;
        pPhrase->doclist.iDocid = 0;
      }
    }

    pExpr->iDocid = 0;
    pExpr->bEof = 0;
    pExpr->bStart = 0;

    fts3EvalRestart(pCsr, pExpr->pLeft, pRc);
    fts3EvalRestart(pCsr, pExpr->pRight, pRc);
  }
}

/*
** After allocating the Fts3Expr.aMI[] array for each phrase in the 
** expression rooted at pExpr, the cursor iterates through all rows matched
** by pExpr, calling this function for each row. This function increments
** the values in Fts3Expr.aMI[] according to the position-list currently
** found in Fts3Expr.pPhrase->doclist.pList for each of the phrase 
** expression nodes.
*/
static void fts3EvalUpdateCounts(Fts3Expr *pExpr){
  if( pExpr ){
    Fts3Phrase *pPhrase = pExpr->pPhrase;
    if( pPhrase && pPhrase->doclist.pList ){
      int iCol = 0;
      char *p = pPhrase->doclist.pList;

      assert( *p );
      while( 1 ){
        u8 c = 0;
        int iCnt = 0;
        while( 0xFE & (*p | c) ){
          if( (c&0x80)==0 ) iCnt++;
          c = *p++ & 0x80;
        }

        /* aMI[iCol*3 + 1] = Number of occurrences
        ** aMI[iCol*3 + 2] = Number of rows containing at least one instance
        */
        pExpr->aMI[iCol*3 + 1] += iCnt;
        pExpr->aMI[iCol*3 + 2] += (iCnt>0);
        if( *p==0x00 ) break;
        p++;
        p += sqlite3Fts3GetVarint32(p, &iCol);
      }
    }

    fts3EvalUpdateCounts(pExpr->pLeft);
    fts3EvalUpdateCounts(pExpr->pRight);
  }
}

/*
** Expression pExpr must be of type FTSQUERY_PHRASE.
**
** If it is not already allocated and populated, this function allocates and
** populates the Fts3Expr.aMI[] array for expression pExpr. If pExpr is part
** of a NEAR expression, then it also allocates and populates the same array
** for all other phrases that are part of the NEAR expression.
**
** SQLITE_OK is returned if the aMI[] array is successfully allocated and
** populated. Otherwise, if an error occurs, an SQLite error code is returned.
*/
static int fts3EvalGatherStats(
  Fts3Cursor *pCsr,               /* Cursor object */
  Fts3Expr *pExpr                 /* FTSQUERY_PHRASE expression */
){
  int rc = SQLITE_OK;             /* Return code */

  assert( pExpr->eType==FTSQUERY_PHRASE );
  if( pExpr->aMI==0 ){
    Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
    Fts3Expr *pRoot;                /* Root of NEAR expression */
    Fts3Expr *p;                    /* Iterator used for several purposes */

    sqlite3_int64 iPrevId = pCsr->iPrevId;
    sqlite3_int64 iDocid;
    u8 bEof;

    /* Find the root of the NEAR expression */
    pRoot = pExpr;
    while( pRoot->pParent && pRoot->pParent->eType==FTSQUERY_NEAR ){
      pRoot = pRoot->pParent;
    }
    iDocid = pRoot->iDocid;
    bEof = pRoot->bEof;
    assert( pRoot->bStart );

    /* Allocate space for the aMSI[] array of each FTSQUERY_PHRASE node */
    for(p=pRoot; p; p=p->pLeft){
      Fts3Expr *pE = (p->eType==FTSQUERY_PHRASE?p:p->pRight);
      assert( pE->aMI==0 );
      pE->aMI = (u32 *)sqlite3_malloc(pTab->nColumn * 3 * sizeof(u32));
      if( !pE->aMI ) return SQLITE_NOMEM;
      memset(pE->aMI, 0, pTab->nColumn * 3 * sizeof(u32));
    }

    fts3EvalRestart(pCsr, pRoot, &rc);

    while( pCsr->isEof==0 && rc==SQLITE_OK ){

      do {
        /* Ensure the %_content statement is reset. */
        if( pCsr->isRequireSeek==0 ) sqlite3_reset(pCsr->pStmt);
        assert( sqlite3_data_count(pCsr->pStmt)==0 );

        /* Advance to the next document */
        fts3EvalNext(pCsr, pRoot, &rc);
        pCsr->isEof = pRoot->bEof;
        pCsr->isRequireSeek = 1;
        pCsr->isMatchinfoNeeded = 1;
        pCsr->iPrevId = pRoot->iDocid;
      }while( pCsr->isEof==0 
           && pRoot->eType==FTSQUERY_NEAR 
           && fts3EvalLoadDeferred(pCsr, &rc) 
      );

      if( rc==SQLITE_OK && pCsr->isEof==0 ){
        fts3EvalUpdateCounts(pRoot);
      }
    }

    pCsr->isEof = 0;
    pCsr->iPrevId = iPrevId;

    if( bEof ){
      pRoot->bEof = bEof;
    }else{
      /* Caution: pRoot may iterate through docids in ascending or descending
      ** order. For this reason, even though it seems more defensive, the 
      ** do loop can not be written:
      **
      **   do {...} while( pRoot->iDocid<iDocid && rc==SQLITE_OK );
      */
      fts3EvalRestart(pCsr, pRoot, &rc);
      do {
        fts3EvalNext(pCsr, pRoot, &rc);
        assert( pRoot->bEof==0 );
      }while( pRoot->iDocid!=iDocid && rc==SQLITE_OK );
      fts3EvalLoadDeferred(pCsr, &rc);
    }
  }
  return rc;
}

/*
** This function is used by the matchinfo() module to query a phrase 
** expression node for the following information:
**
**   1. The total number of occurrences of the phrase in each column of 
**      the FTS table (considering all rows), and
**
**   2. For each column, the number of rows in the table for which the
**      column contains at least one instance of the phrase.
**
** If no error occurs, SQLITE_OK is returned and the values for each column
** written into the array aiOut as follows:
**
**   aiOut[iCol*3 + 1] = Number of occurrences
**   aiOut[iCol*3 + 2] = Number of rows containing at least one instance
**
** Caveats:
**
**   * If a phrase consists entirely of deferred tokens, then all output 
**     values are set to the number of documents in the table. In other
**     words we assume that very common tokens occur exactly once in each 
**     column of each row of the table.
**
**   * If a phrase contains some deferred tokens (and some non-deferred 
**     tokens), count the potential occurrence identified by considering
**     the non-deferred tokens instead of actual phrase occurrences.
**
**   * If the phrase is part of a NEAR expression, then only phrase instances
**     that meet the NEAR constraint are included in the counts.
*/
int sqlite3Fts3EvalPhraseStats(
  Fts3Cursor *pCsr,               /* FTS cursor handle */
  Fts3Expr *pExpr,                /* Phrase expression */
  u32 *aiOut                      /* Array to write results into (see above) */
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int rc = SQLITE_OK;
  int iCol;

  if( pExpr->bDeferred && pExpr->pParent->eType!=FTSQUERY_NEAR ){
    assert( pCsr->nDoc>0 );
    for(iCol=0; iCol<pTab->nColumn; iCol++){
      aiOut[iCol*3 + 1] = pCsr->nDoc;
      aiOut[iCol*3 + 2] = pCsr->nDoc;
    }
  }else{
    rc = fts3EvalGatherStats(pCsr, pExpr);
    if( rc==SQLITE_OK ){
      assert( pExpr->aMI );
      for(iCol=0; iCol<pTab->nColumn; iCol++){
        aiOut[iCol*3 + 1] = pExpr->aMI[iCol*3 + 1];
        aiOut[iCol*3 + 2] = pExpr->aMI[iCol*3 + 2];
      }
    }
  }

  return rc;
}

/*
** The expression pExpr passed as the second argument to this function
** must be of type FTSQUERY_PHRASE. 
**
** The returned value is either NULL or a pointer to a buffer containing
** a position-list indicating the occurrences of the phrase in column iCol
** of the current row. 
**
** More specifically, the returned buffer contains 1 varint for each 
** occurence of the phrase in the column, stored using the normal (delta+2) 
** compression and is terminated by either an 0x01 or 0x00 byte. For example,
** if the requested column contains "a b X c d X X" and the position-list
** for 'X' is requested, the buffer returned may contain:
**
**     0x04 0x05 0x03 0x01   or   0x04 0x05 0x03 0x00
**
** This function works regardless of whether or not the phrase is deferred,
** incremental, or neither.
*/
char *sqlite3Fts3EvalPhrasePoslist(
  Fts3Cursor *pCsr,               /* FTS3 cursor object */
  Fts3Expr *pExpr,                /* Phrase to return doclist for */
  int iCol                        /* Column to return position list for */
){
  Fts3Phrase *pPhrase = pExpr->pPhrase;
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  char *pIter = pPhrase->doclist.pList;
  int iThis;

  assert( iCol>=0 && iCol<pTab->nColumn );
  if( !pIter 
   || pExpr->bEof 
   || pExpr->iDocid!=pCsr->iPrevId
   || (pPhrase->iColumn<pTab->nColumn && pPhrase->iColumn!=iCol) 
  ){
    return 0;
  }

  assert( pPhrase->doclist.nList>0 );
  if( *pIter==0x01 ){
    pIter++;
    pIter += sqlite3Fts3GetVarint32(pIter, &iThis);
  }else{
    iThis = 0;
  }
  while( iThis<iCol ){
    fts3ColumnlistCopy(0, &pIter);
    if( *pIter==0x00 ) return 0;
    pIter++;
    pIter += sqlite3Fts3GetVarint32(pIter, &iThis);
  }

  return ((iCol==iThis)?pIter:0);
}

/*
** Free all components of the Fts3Phrase structure that were allocated by
** the eval module. Specifically, this means to free:
**
**   * the contents of pPhrase->doclist, and
**   * any Fts3MultiSegReader objects held by phrase tokens.
*/
void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *pPhrase){
  if( pPhrase ){
    int i;
    sqlite3_free(pPhrase->doclist.aAll);
    fts3EvalZeroPoslist(pPhrase);
    memset(&pPhrase->doclist, 0, sizeof(Fts3Doclist));
    for(i=0; i<pPhrase->nToken; i++){
      fts3SegReaderCursorFree(pPhrase->aToken[i].pSegcsr);
      pPhrase->aToken[i].pSegcsr = 0;
    }
  }
}

#endif

/*
** Macro to return the number of elements in an array. SQLite has a
** similar macro called ArraySize(). Use a different name to avoid
** a collision when building an amalgamation with built-in FTS3.
*/
#define SizeofArray(X) ((int)(sizeof(X)/sizeof(X[0])))


#ifndef MIN
# define MIN(x,y) ((x)<(y)?(x):(y))
#endif

/*
** Maximum length of a varint encoded integer. The varint format is different
** from that used by SQLite, so the maximum length is 10, not 9.
*/
#define FTS3_VARINT_MAX 10

/*
** FTS4 virtual tables may maintain multiple indexes - one index of all terms
** in the document set and zero or more prefix indexes. All indexes are stored
** as one or more b+-trees in the %_segments and %_segdir tables. 
**
** It is possible to determine which index a b+-tree belongs to based on the
** value stored in the "%_segdir.level" column. Given this value L, the index
** that the b+-tree belongs to is (L<<10). In other words, all b+-trees with
** level values between 0 and 1023 (inclusive) belong to index 0, all levels
** between 1024 and 2047 to index 1, and so on.
**
** It is considered impossible for an index to use more than 1024 levels. In 
** theory though this may happen, but only after at least 
** (FTS3_MERGE_COUNT^1024) separate flushes of the pending-terms tables.
*/
#define FTS3_SEGDIR_MAXLEVEL      1024
#define FTS3_SEGDIR_MAXLEVEL_STR "1024"

/*
** The testcase() macro is only used by the amalgamation.  If undefined,
** make it a no-op.
*/
#ifndef testcase
# define testcase(X)
#endif

typedef struct Fts3Table Fts3Table;
typedef struct Fts3Cursor Fts3Cursor;
typedef struct Fts3Expr Fts3Expr;
typedef struct Fts3Phrase Fts3Phrase;
typedef struct Fts3PhraseToken Fts3PhraseToken;

typedef struct Fts3Doclist Fts3Doclist;
typedef struct Fts3SegFilter Fts3SegFilter;
typedef struct Fts3DeferredToken Fts3DeferredToken;
typedef struct Fts3SegReader Fts3SegReader;
typedef struct Fts3MultiSegReader Fts3MultiSegReader;

/*
** A connection to a fulltext index is an instance of the following
** structure. The xCreate and xConnect methods create an instance
** of this structure and xDestroy and xDisconnect free that instance.
** All other methods receive a pointer to the structure as one of their
** arguments.
*/
struct Fts3Table {
  sqlite3_vtab base;              /* Base class used by SQLite core */
  sqlite3 *db;                    /* The database connection */
  const char *zDb;                /* logical database name */
  const char *zName;              /* virtual table name */
  int nColumn;                    /* number of named columns in virtual table */
  char **azColumn;                /* column names.  malloced */
  sqlite3_tokenizer *pTokenizer;  /* tokenizer for inserts and queries */

  /* Precompiled statements used by the implementation. Each of these 
  ** statements is run and reset within a single virtual table API call. 
  */
  sqlite3_stmt *aStmt[27];

  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 */
  u8 bDescIdx;                    /* True if doclists are in reverse order */
  int nPgsz;                      /* Page size for host database */
  char *zSegmentsTbl;             /* Name of %_segments table */
  sqlite3_blob *pSegments;        /* Blob handle open on %_segments table */

  /* TODO: Fix the first paragraph of this comment.
  **
  ** The following hash table is used to buffer pending index updates during
  ** transactions. Variable nPendingData estimates the memory size of the 
  ** pending data, including hash table overhead, but not malloc overhead. 
  ** When nPendingData exceeds nMaxPendingData, the buffer is flushed 
  ** automatically. Variable iPrevDocid is the docid of the most recently
  ** inserted record.
  **
  ** A single FTS4 table may have multiple full-text indexes. For each index
  ** there is an entry in the aIndex[] array. Index 0 is an index of all the
  ** terms that appear in the document set. Each subsequent index in aIndex[]
  ** is an index of prefixes of a specific length.
  */
  int nIndex;                     /* Size of aIndex[] */
  struct Fts3Index {
    int nPrefix;                  /* Prefix length (0 for main terms index) */
    Fts3Hash hPending;            /* Pending terms table for this index */
  } *aIndex;
  int nMaxPendingData;            /* Max pending data before flush to disk */
  int nPendingData;               /* Current bytes of pending data */
  sqlite_int64 iPrevDocid;        /* Docid of most recently inserted document */


#if defined(SQLITE_DEBUG)
  /* State variables used for validating that the transaction control
  ** methods of the virtual table are called at appropriate times.  These
  ** values do not contribution to the FTS computation; they are used for
  ** verifying the SQLite core.
  */

  Fts3Expr *pExpr;                /* Parsed MATCH query string */
  int nPhrase;                    /* Number of matchable phrases in query */
  Fts3DeferredToken *pDeferred;   /* Deferred search tokens, if any */
  sqlite3_int64 iPrevId;          /* Previous id read from aDoclist */
  char *pNextId;                  /* Pointer into the body of aDoclist */
  char *aDoclist;                 /* List of docids for full-text queries */
  int nDoclist;                   /* Size of buffer at aDoclist */
  u8 bDesc;                       /* True to sort in descending order */
  int eEvalmode;                  /* An FTS3_EVAL_XX constant */
  int nRowAvg;                    /* Average size of database rows, in pages */
  int nDoc;                       /* Documents in table */

  int isMatchinfoNeeded;          /* True when aMatchinfo[] needs filling in */
  u32 *aMatchinfo;                /* Information about most recent match */
  int nMatchinfo;                 /* Number of elements in aMatchinfo[] */
  char *zMatchinfo;               /* Matchinfo specification */
};

** indicating that all columns should be searched,
** then eSearch would be set to FTS3_FULLTEXT_SEARCH+4.
*/
#define FTS3_FULLSCAN_SEARCH 0    /* Linear scan of %_content table */
#define FTS3_DOCID_SEARCH    1    /* Lookup by rowid on %_content table */
#define FTS3_FULLTEXT_SEARCH 2    /* Full-text index search */


struct Fts3Doclist {
  char *aAll;                    /* Array containing doclist (or NULL) */
  int nAll;                      /* Size of a[] in bytes */
  char *pNextDocid;              /* Pointer to next docid */

  sqlite3_int64 iDocid;          /* Current docid (if pList!=0) */
  int bFreeList;                 /* True if pList should be sqlite3_free()d */
  char *pList;                   /* Pointer to position list following iDocid */
  int nList;                     /* Length of position list */
} doclist;

/*
** A "phrase" is a sequence of one or more tokens that must match in
** sequence.  A single token is the base case and the most common case.
** For a sequence of tokens contained in double-quotes (i.e. "one two three")
** nToken will be the number of tokens in the string.






*/
struct Fts3PhraseToken {
  char *z;                        /* Text of the token */
  int n;                          /* Number of bytes in buffer z */
  int isPrefix;                   /* True if token ends with a "*" character */

  /* Variables above this point are populated when the expression is
  ** parsed (by code in fts3_expr.c). Below this point the variables are
  ** used when evaluating the expression. */
  int bFulltext;                  /* True if full-text index was used */

  Fts3DeferredToken *pDeferred;   /* Deferred token object for this token */
  Fts3MultiSegReader *pSegcsr;    /* Segment-reader for this token */
};

struct Fts3Phrase {
  /* Cache of doclist for this phrase. */
  Fts3Doclist doclist;
  int bIncr;                 /* True if doclist is loaded incrementally */

  /* Variables below this point are populated by fts3_expr.c when parsing 
  ** a MATCH expression. Everything above is part of the evaluation phase. 
  */
  int nToken;                /* Number of tokens in the phrase */
  int iColumn;               /* Index of column this phrase must match */

  Fts3PhraseToken aToken[1]; /* One entry for each token in the phrase */
};

/*
** A tree of these objects forms the RHS of a MATCH operator.
**
** If Fts3Expr.eType is FTSQUERY_PHRASE and isLoaded is true, then aDoclist 
** points to a malloced buffer, size nDoclist bytes, containing the results 
** of this phrase query in FTS3 doclist format. As usual, the initial 
** "Length" field found in doclists stored on disk is omitted from this 
** buffer.
**
** Variable aMI is used only for FTSQUERY_NEAR nodes to store the global
** matchinfo data. If it is not NULL, it points to an array of size nCol*3,
** where nCol is the number of columns in the queried FTS table. The array
** is populated as follows:
**
**   aMI[iCol*3 + 0] = Undefined
**   aMI[iCol*3 + 1] = Number of occurrences
**   aMI[iCol*3 + 2] = Number of rows containing at least one instance
**
** The aMI array is allocated using sqlite3_malloc(). It should be freed 
** when the expression node is.
*/
struct Fts3Expr {
  int eType;                 /* One of the FTSQUERY_XXX values defined below */
  int nNear;                 /* Valid if eType==FTSQUERY_NEAR */
  Fts3Expr *pParent;         /* pParent->pLeft==this or pParent->pRight==this */
  Fts3Expr *pLeft;           /* Left operand */
  Fts3Expr *pRight;          /* Right operand */
  Fts3Phrase *pPhrase;       /* Valid if eType==FTSQUERY_PHRASE */

  /* The following are used by the fts3_eval.c module. */
  sqlite3_int64 iDocid;      /* Current docid */
  u8 bEof;                   /* True this expression is at EOF already */
  u8 bStart;                 /* True if iDocid is valid */
  u8 bDeferred;              /* True if this expression is entirely deferred */


  u32 *aMI;
};

/*
** Candidate values for Fts3Query.eType. Note that the order of the first
** four values is in order of precedence when parsing expressions. For 
** example, the following:
**

/* fts3_write.c */
int sqlite3Fts3UpdateMethod(sqlite3_vtab*,int,sqlite3_value**,sqlite3_int64*);
int sqlite3Fts3PendingTermsFlush(Fts3Table *);
void sqlite3Fts3PendingTermsClear(Fts3Table *);
int sqlite3Fts3Optimize(Fts3Table *);
int sqlite3Fts3SegReaderNew(int, sqlite3_int64,
  sqlite3_int64, sqlite3_int64, const char *, int, Fts3SegReader**);
int sqlite3Fts3SegReaderPending(
  Fts3Table*,int,const char*,int,int,Fts3SegReader**);
void sqlite3Fts3SegReaderFree(Fts3SegReader *);

int sqlite3Fts3AllSegdirs(Fts3Table*, int, int, sqlite3_stmt **);
int sqlite3Fts3ReadLock(Fts3Table *);
int sqlite3Fts3ReadBlock(Fts3Table*, sqlite3_int64, char **, int*, int*);

int sqlite3Fts3SelectDoctotal(Fts3Table *, sqlite3_stmt **);
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 *);
void sqlite3Fts3SegReaderFinish(Fts3MultiSegReader *);

int sqlite3Fts3SegReaderCursor(
    Fts3Table *, int, int, const char *, int, int, int, Fts3MultiSegReader *);

/* Flags allowed as part of the 4th argument to SegmentReaderIterate() */
#define FTS3_SEGMENT_REQUIRE_POS   0x00000001
#define FTS3_SEGMENT_IGNORE_EMPTY  0x00000002
#define FTS3_SEGMENT_COLUMN_FILTER 0x00000004
#define FTS3_SEGMENT_PREFIX        0x00000008
#define FTS3_SEGMENT_SCAN          0x00000010

/* Type passed as 4th argument to SegmentReaderIterate() */
struct Fts3SegFilter {
  const char *zTerm;
  int nTerm;
  int iCol;
  int flags;
};

struct Fts3MultiSegReader {
  /* Used internally by sqlite3Fts3SegReaderXXX() calls */
  Fts3SegReader **apSegment;      /* Array of Fts3SegReader objects */
  int nSegment;                   /* Size of apSegment array */
  int nAdvance;                   /* How many seg-readers to advance */
  Fts3SegFilter *pFilter;         /* Pointer to filter object */
  char *aBuffer;                  /* Buffer to merge doclists in */
  int nBuffer;                    /* Allocated size of aBuffer[] in bytes */

  int iColFilter;                 /* If >=0, filter for this column */

  /* Used by fts3.c only. */
  int nCost;                      /* Cost of running iterator */
  int bLookup;                    /* True if a lookup of a single entry. */

  /* Output values. Valid only after Fts3SegReaderStep() returns SQLITE_ROW. */
  char *zTerm;                    /* Pointer to term buffer */
  int nTerm;                      /* Size of zTerm in bytes */
  char *aDoclist;                 /* Pointer to doclist buffer */
  int nDoclist;                   /* Size of aDoclist[] in bytes */
};

/* fts3.c */
int sqlite3Fts3PutVarint(char *, sqlite3_int64);
int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
int sqlite3Fts3GetVarint32(const char *, int *);
int sqlite3Fts3VarintLen(sqlite3_uint64);
void sqlite3Fts3Dequote(char *);
void sqlite3Fts3DoclistPrev(int,char*,int,char**,sqlite3_int64*,int*,u8*);


int sqlite3Fts3EvalPhraseStats(Fts3Cursor *, Fts3Expr *, u32 *);



/* fts3_tokenizer.c */
const char *sqlite3Fts3NextToken(const char *, int *);
int sqlite3Fts3InitHashTable(sqlite3 *, Fts3Hash *, const char *);
int sqlite3Fts3InitTokenizer(Fts3Hash *pHash, const char *, 
    sqlite3_tokenizer **, char **
);

#ifdef SQLITE_TEST
int sqlite3Fts3ExprInitTestInterface(sqlite3 *db);
int sqlite3Fts3InitTerm(sqlite3 *db);
#endif

/* fts3_aux.c */
int sqlite3Fts3InitAux(sqlite3 *db);

int sqlite3Fts3TermSegReaderCursor(
  Fts3Cursor *pCsr,               /* Virtual table cursor handle */
  const char *zTerm,              /* Term to query for */
  int nTerm,                      /* Size of zTerm in bytes */
  int isPrefix,                   /* True for a prefix search */
  Fts3MultiSegReader **ppSegcsr   /* OUT: Allocated seg-reader cursor */
);

void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *);

int sqlite3Fts3EvalStart(Fts3Cursor *, Fts3Expr *, int);
int sqlite3Fts3EvalNext(Fts3Cursor *pCsr);

int sqlite3Fts3MsrIncrStart(
    Fts3Table*, Fts3MultiSegReader*, int, const char*, int);
int sqlite3Fts3MsrIncrNext(
    Fts3Table *, Fts3MultiSegReader *, sqlite3_int64 *, char **, int *);
char *sqlite3Fts3EvalPhrasePoslist(Fts3Cursor *, Fts3Expr *, int iCol); 
int sqlite3Fts3MsrOvfl(Fts3Cursor *, Fts3MultiSegReader *, int *);

int sqlite3Fts3DeferredTokenList(Fts3DeferredToken *, char **, int *);


#endif /* _FTSINT_H */

struct Fts3auxTable {
  sqlite3_vtab base;              /* Base class used by SQLite core */
  Fts3Table *pFts3Tab;
};

struct Fts3auxCursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  Fts3MultiSegReader csr;        /* Must be right after "base" */
  Fts3SegFilter filter;
  char *zStop;
  int nStop;                      /* Byte-length of string zStop */
  int isEof;                      /* True if cursor is at EOF */
  sqlite3_int64 iRowid;           /* Current rowid */

  int iCol;                       /* Current value of 'col' column */

  if( !p ) return SQLITE_NOMEM;
  memset(p, 0, nByte);

  p->pFts3Tab = (Fts3Table *)&p[1];
  p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
  p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
  p->pFts3Tab->db = db;
  p->pFts3Tab->nIndex = 1;

  memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
  memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
  sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);

  *ppVtab = (sqlite3_vtab *)p;
  return SQLITE_OK;

  if( idxNum&FTS4AUX_LE_CONSTRAINT ){
    int iIdx = (idxNum&FTS4AUX_GE_CONSTRAINT) ? 1 : 0;
    pCsr->zStop = sqlite3_mprintf("%s", sqlite3_value_text(apVal[iIdx]));
    pCsr->nStop = sqlite3_value_bytes(apVal[iIdx]);
    if( pCsr->zStop==0 ) return SQLITE_NOMEM;
  }

  rc = sqlite3Fts3SegReaderCursor(pFts3, 0, FTS3_SEGCURSOR_ALL,
      pCsr->filter.zTerm, pCsr->filter.nTerm, 0, isScan, &pCsr->csr
  );
  if( rc==SQLITE_OK ){
    rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
  }

  if( rc==SQLITE_OK ) rc = fts3auxNextMethod(pCursor);

*/
#define SQLITE_FTS3_DEFAULT_NEAR_PARAM 10

#include "fts3Int.h"
#include <string.h>
#include <assert.h>

/*
** isNot:
**   This variable is used by function getNextNode(). When getNextNode() is
**   called, it sets ParseContext.isNot to true if the 'next node' is a 
**   FTSQUERY_PHRASE with a unary "-" attached to it. i.e. "mysql" in the
**   FTS3 query "sqlite -mysql". Otherwise, ParseContext.isNot is set to
**   zero.
*/
typedef struct ParseContext ParseContext;
struct ParseContext {
  sqlite3_tokenizer *pTokenizer;      /* Tokenizer module */
  const char **azCol;                 /* Array of column names for fts3 table */
  int nCol;                           /* Number of entries in azCol[] */
  int iDefaultCol;                    /* Default column to query */
  int isNot;                          /* True if getNextNode() sees a unary - */
  sqlite3_context *pCtx;              /* Write error message here */
  int nNest;                          /* Number of nested brackets */
};

/*
** This function is equivalent to the standard isspace() function. 
**

        memcpy(pRet->pPhrase->aToken[0].z, zToken, nToken);

        if( iEnd<n && z[iEnd]=='*' ){
          pRet->pPhrase->aToken[0].isPrefix = 1;
          iEnd++;
        }
        if( !sqlite3_fts3_enable_parentheses && iStart>0 && z[iStart-1]=='-' ){
          pParse->isNot = 1;
        }
      }
      nConsumed = iEnd;
    }

    pModule->xClose(pCursor);
  }

  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
  int rc;
  Fts3Expr *p = 0;
  sqlite3_tokenizer_cursor *pCursor = 0;
  char *zTemp = 0;
  int nTemp = 0;

  const int nSpace = sizeof(Fts3Expr) + sizeof(Fts3Phrase);
  int nToken = 0;

  /* The final Fts3Expr data structure, including the Fts3Phrase,
  ** Fts3PhraseToken structures token buffers are all stored as a single 
  ** allocation so that the expression can be freed with a single call to
  ** sqlite3_free(). Setting this up requires a two pass approach.
  **
  ** The first pass, in the block below, uses a tokenizer cursor to iterate
  ** through the tokens in the expression. This pass uses fts3ReallocOrFree()
  ** to assemble data in two dynamic buffers:
  **
  **   Buffer p: Points to the Fts3Expr structure, followed by the Fts3Phrase
  **             structure, followed by the array of Fts3PhraseToken 
  **             structures. This pass only populates the Fts3PhraseToken array.
  **
  **   Buffer zTemp: Contains copies of all tokens.
  **
  ** The second pass, in the block that begins "if( rc==SQLITE_DONE )" below,
  ** appends buffer zTemp to buffer p, and fills in the Fts3Expr and Fts3Phrase
  ** structures.
  */
  rc = pModule->xOpen(pTokenizer, zInput, nInput, &pCursor);
  if( rc==SQLITE_OK ){
    int ii;
    pCursor->pTokenizer = pTokenizer;
    for(ii=0; rc==SQLITE_OK; ii++){
      const char *zByte;
      int nByte, iBegin, iEnd, iPos;
      rc = pModule->xNext(pCursor, &zByte, &nByte, &iBegin, &iEnd, &iPos);
      if( rc==SQLITE_OK ){
        Fts3PhraseToken *pToken;

        p = fts3ReallocOrFree(p, nSpace + ii*sizeof(Fts3PhraseToken));

        if( !p ) goto no_mem;

        zTemp = fts3ReallocOrFree(zTemp, nTemp + nByte);
        if( !zTemp ) goto no_mem;



        assert( nToken==ii );
        pToken = &((Fts3Phrase *)(&p[1]))->aToken[ii];
        memset(pToken, 0, sizeof(Fts3PhraseToken));


        memcpy(&zTemp[nTemp], zByte, nByte);
        nTemp += nByte;





        pToken->n = nByte;
        pToken->isPrefix = (iEnd<nInput && zInput[iEnd]=='*');
        nToken = ii+1;
      }
    }

    pModule->xClose(pCursor);
    pCursor = 0;
  }

  if( rc==SQLITE_DONE ){
    int jj;
    char *zBuf = 0;



    p = fts3ReallocOrFree(p, nSpace + nToken*sizeof(Fts3PhraseToken) + nTemp);
    if( !p ) goto no_mem;
    memset(p, 0, (char *)&(((Fts3Phrase *)&p[1])->aToken[0])-(char *)p);
    p->eType = FTSQUERY_PHRASE;
    p->pPhrase = (Fts3Phrase *)&p[1];
    p->pPhrase->iColumn = pParse->iDefaultCol;
    p->pPhrase->nToken = nToken;


    zBuf = (char *)&p->pPhrase->aToken[nToken];
    memcpy(zBuf, zTemp, nTemp);

    sqlite3_free(zTemp);


    for(jj=0; jj<p->pPhrase->nToken; jj++){
      p->pPhrase->aToken[jj].z = zBuf;
      zBuf += p->pPhrase->aToken[jj].n;
    }



    rc = SQLITE_OK;
  }

  *ppExpr = p;
  return rc;
no_mem:

  int iCol;
  int iColLen;
  int rc;
  Fts3Expr *pRet = 0;

  const char *zInput = z;
  int nInput = n;

  pParse->isNot = 0;

  /* Skip over any whitespace before checking for a keyword, an open or
  ** close bracket, or a quoted string. 
  */
  while( nInput>0 && fts3isspace(*zInput) ){
    nInput--;
    zInput++;

    Fts3Expr *p = 0;
    int nByte = 0;
    rc = getNextNode(pParse, zIn, nIn, &p, &nByte);
    if( rc==SQLITE_OK ){
      int isPhrase;

      if( !sqlite3_fts3_enable_parentheses 
       && p->eType==FTSQUERY_PHRASE && pParse->isNot 
      ){
        /* Create an implicit NOT operator. */
        Fts3Expr *pNot = fts3MallocZero(sizeof(Fts3Expr));
        if( !pNot ){
          sqlite3Fts3ExprFree(p);
          rc = SQLITE_NOMEM;
          goto exprparse_out;
        }
        pNot->eType = FTSQUERY_NOT;
        pNot->pRight = p;
        if( pNotBranch ){
          pNot->pLeft = pNotBranch;
        }
        pNotBranch = pNot;
        p = pPrev;
      }else{
        int eType = p->eType;

        isPhrase = (eType==FTSQUERY_PHRASE || p->pLeft);

        /* The isRequirePhrase variable is set to true if a phrase or
        ** an expression contained in parenthesis is required. If a
        ** binary operator (AND, OR, NOT or NEAR) is encounted when
        ** isRequirePhrase is set, this is a syntax error.
        */

}

/*
** Free a parsed fts3 query expression allocated by sqlite3Fts3ExprParse().
*/
void sqlite3Fts3ExprFree(Fts3Expr *p){
  if( p ){
    assert( p->eType==FTSQUERY_PHRASE || p->pPhrase==0 );
    sqlite3Fts3ExprFree(p->pLeft);
    sqlite3Fts3ExprFree(p->pRight);
    sqlite3Fts3EvalPhraseCleanup(p->pPhrase);
    sqlite3_free(p->aMI);
    sqlite3_free(p);
  }
}

/****************************************************************************
*****************************************************************************
** Everything after this point is just test code.

*/
static char *exprToString(Fts3Expr *pExpr, char *zBuf){
  switch( pExpr->eType ){
    case FTSQUERY_PHRASE: {
      Fts3Phrase *pPhrase = pExpr->pPhrase;
      int i;
      zBuf = sqlite3_mprintf(
          "%zPHRASE %d 0", zBuf, pPhrase->iColumn);
      for(i=0; zBuf && i<pPhrase->nToken; i++){
        zBuf = sqlite3_mprintf("%z %.*s%s", zBuf, 
            pPhrase->aToken[i].n, pPhrase->aToken[i].z,
            (pPhrase->aToken[i].isPrefix?"+":"")
        );
      }
      return zBuf;

  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
  void *pCtx                      /* Second argument to pass to callback */
){
  int iPhrase = 0;                /* Variable used as the phrase counter */
  return fts3ExprIterate2(pExpr, &iPhrase, x, pCtx);
}














































/*
** This is an fts3ExprIterate() callback used while loading the doclists
** for each phrase into Fts3Expr.aDoclist[]/nDoclist. See also
** fts3ExprLoadDoclists().
*/
static int fts3ExprLoadDoclistsCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
  int rc = SQLITE_OK;
  Fts3Phrase *pPhrase = pExpr->pPhrase;
  LoadDoclistCtx *p = (LoadDoclistCtx *)ctx;

  UNUSED_PARAMETER(iPhrase);

  p->nPhrase++;
  p->nToken += pPhrase->nToken;









  return rc;
}

/*
** Load the doclists for each phrase in the query associated with FTS3 cursor
** pCsr. 

static int fts3SnippetFindPositions(Fts3Expr *pExpr, int iPhrase, void *ctx){
  SnippetIter *p = (SnippetIter *)ctx;
  SnippetPhrase *pPhrase = &p->aPhrase[iPhrase];
  char *pCsr;

  pPhrase->nToken = pExpr->pPhrase->nToken;

  pCsr = sqlite3Fts3EvalPhrasePoslist(p->pCsr, pExpr, p->iCol);
  if( pCsr ){
    int iFirst = 0;
    pPhrase->pList = pCsr;
    fts3GetDeltaPosition(&pCsr, &iFirst);
    pPhrase->pHead = pCsr;
    pPhrase->pTail = pCsr;
    pPhrase->iHead = iFirst;

    if( !c ) nEntry++;
  }

  *ppCollist = pEnd;
  return nEntry;
}





















/*
** fts3ExprIterate() callback used to collect the "global" matchinfo stats
** for a single query. 
**
** fts3ExprIterate() callback to load the 'global' elements of a
** FTS3_MATCHINFO_HITS matchinfo array. The global stats are those elements 
** of the matchinfo array that are constant for all rows returned by the 

*/
static int fts3ExprGlobalHitsCb(
  Fts3Expr *pExpr,                /* Phrase expression node */
  int iPhrase,                    /* Phrase number (numbered from zero) */
  void *pCtx                      /* Pointer to MatchInfo structure */
){
  MatchInfo *p = (MatchInfo *)pCtx;
  return sqlite3Fts3EvalPhraseStats(



      p->pCursor, pExpr, &p->aMatchinfo[3*iPhrase*p->nCol]
  );




































}

/*
** fts3ExprIterate() callback used to collect the "local" part of the
** FTS3_MATCHINFO_HITS array. The local stats are those elements of the 
** array that are different for each row returned by the query.
*/
static int fts3ExprLocalHitsCb(
  Fts3Expr *pExpr,                /* Phrase expression node */
  int iPhrase,                    /* Phrase number */
  void *pCtx                      /* Pointer to MatchInfo structure */
){
  MatchInfo *p = (MatchInfo *)pCtx;
  int iStart = iPhrase * p->nCol * 3;
  int i;

  for(i=0; i<p->nCol; i++){


    char *pCsr;
    pCsr = sqlite3Fts3EvalPhrasePoslist(p->pCursor, pExpr, i);

    if( pCsr ){
      p->aMatchinfo[iStart+i*3] = fts3ColumnlistCount(&pCsr);
    }else{
      p->aMatchinfo[iStart+i*3] = 0;
    }
  }

  return SQLITE_OK;
}

static int fts3MatchinfoCheck(

** iterating through a multi-column position-list corresponding to the
** hits for a single phrase on a single row in order to calculate the
** values for a matchinfo() FTS3_MATCHINFO_LCS request.
*/
typedef struct LcsIterator LcsIterator;
struct LcsIterator {
  Fts3Expr *pExpr;                /* Pointer to phrase expression */

  int iPosOffset;                 /* Tokens count up to end of this phrase */
  char *pRead;                    /* Cursor used to iterate through aDoclist */
  int iPos;                       /* Current position */
};

/* 
** If LcsIterator.iCol is set to the following value, the iterator has
** finished iterating through all offsets for all columns.
*/

*/
static int fts3LcsIteratorAdvance(LcsIterator *pIter){
  char *pRead = pIter->pRead;
  sqlite3_int64 iRead;
  int rc = 0;

  pRead += sqlite3Fts3GetVarint(pRead, &iRead);
  if( iRead==0 || iRead==1 ){
    pRead = 0;
    rc = 1;
  }else{







    pIter->iPos += (int)(iRead-2);
  }

  pIter->pRead = pRead;
  return rc;
}
  

  /* Allocate and populate the array of LcsIterator objects. The array
  ** contains one element for each matchable phrase in the query.
  **/
  aIter = sqlite3_malloc(sizeof(LcsIterator) * pCsr->nPhrase);
  if( !aIter ) return SQLITE_NOMEM;
  memset(aIter, 0, sizeof(LcsIterator) * pCsr->nPhrase);
  (void)fts3ExprIterate(pCsr->pExpr, fts3MatchinfoLcsCb, (void*)aIter);

  for(i=0; i<pInfo->nPhrase; i++){
    LcsIterator *pIter = &aIter[i];
    nToken -= pIter->pExpr->pPhrase->nToken;
    pIter->iPosOffset = nToken;







  }

  for(iCol=0; iCol<pInfo->nCol; iCol++){
    int nLcs = 0;                 /* LCS value for this column */
    int nLive = 0;                /* Number of iterators in aIter not at EOF */




    for(i=0; i<pInfo->nPhrase; i++){
      LcsIterator *pIt = &aIter[i];
      pIt->pRead = sqlite3Fts3EvalPhrasePoslist(pCsr, pIt->pExpr, iCol);
      if( pIt->pRead ){
        pIt->iPos = pIt->iPosOffset;
        fts3LcsIteratorAdvance(&aIter[i]);
        nLive++;
      }
    }




    while( nLive>0 ){
      LcsIterator *pAdv = 0;      /* The iterator to advance by one position */
      int nThisLcs = 0;           /* LCS for the current iterator positions */

      for(i=0; i<pInfo->nPhrase; i++){
        LcsIterator *pIter = &aIter[i];
        if( pIter->pRead==0 ){
          /* This iterator is already at EOF for this column. */
          nThisLcs = 0;
        }else{
          if( pAdv==0 || pIter->iPos<pAdv->iPos ){
            pAdv = pIter;
          }
          if( nThisLcs==0 || pIter->iPos==pIter[-1].iPos ){

  TermOffsetCtx *p = (TermOffsetCtx *)ctx;
  int nTerm;                      /* Number of tokens in phrase */
  int iTerm;                      /* For looping through nTerm phrase terms */
  char *pList;                    /* Pointer to position list for phrase */
  int iPos = 0;                   /* First position in position-list */

  UNUSED_PARAMETER(iPhrase);
  pList = sqlite3Fts3EvalPhrasePoslist(p->pCsr, pExpr, p->iCol);
  nTerm = pExpr->pPhrase->nToken;
  if( pList ){
    fts3GetDeltaPosition(&pList, &iPos);
    assert( iPos>=0 );
  }

  for(iTerm=0; iTerm<nTerm; iTerm++){

#include <assert.h>

typedef struct Fts3termTable Fts3termTable;
typedef struct Fts3termCursor Fts3termCursor;

struct Fts3termTable {
  sqlite3_vtab base;              /* Base class used by SQLite core */
  int iIndex;                     /* Index for Fts3Table.aIndex[] */
  Fts3Table *pFts3Tab;
};

struct Fts3termCursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  Fts3MultiSegReader csr;        /* Must be right after "base" */
  Fts3SegFilter filter;

  int isEof;                      /* True if cursor is at EOF */
  char *pNext;

  sqlite3_int64 iRowid;           /* Current 'rowid' value */
  sqlite3_int64 iDocid;           /* Current 'docid' value */

/*
** This function does all the work for both the xConnect and xCreate methods.
** These tables have no persistent representation of their own, so xConnect
** and xCreate are identical operations.
*/
static int fts3termConnectMethod(
  sqlite3 *db,                    /* Database connection */
  void *pCtx,                     /* Non-zero for an fts4prefix 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 */
){
  char const *zDb;                /* Name of database (e.g. "main") */
  char const *zFts3;              /* Name of fts3 table */
  int nDb;                        /* Result of strlen(zDb) */
  int nFts3;                      /* Result of strlen(zFts3) */
  int nByte;                      /* Bytes of space to allocate here */
  int rc;                         /* value returned by declare_vtab() */
  Fts3termTable *p;                /* Virtual table object to return */
  int iIndex = 0;


  if( argc==5 ){
    iIndex = atoi(argv[4]);
    argc--;
  }

  /* The user should specify a single argument - the name of an fts3 table. */
  if( argc!=4 ){
    *pzErr = sqlite3_mprintf(
        "wrong number of arguments to fts4term constructor"
    );
    return SQLITE_ERROR;

  if( !p ) return SQLITE_NOMEM;
  memset(p, 0, nByte);

  p->pFts3Tab = (Fts3Table *)&p[1];
  p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
  p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
  p->pFts3Tab->db = db;
  p->pFts3Tab->nIndex = iIndex+1;
  p->iIndex = iIndex;

  memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
  memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
  sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);

  *ppVtab = (sqlite3_vtab *)p;
  return SQLITE_OK;

  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 */
){
  Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
  Fts3termTable *p = (Fts3termTable *)pCursor->pVtab;
  Fts3Table *pFts3 = p->pFts3Tab;
  int rc;

  UNUSED_PARAMETER(nVal);
  UNUSED_PARAMETER(idxNum);
  UNUSED_PARAMETER(idxStr);
  UNUSED_PARAMETER(apVal);

  assert( idxStr==0 && idxNum==0 );

  /* In case this cursor is being reused, close and zero it. */
  testcase(pCsr->filter.zTerm);
  sqlite3Fts3SegReaderFinish(&pCsr->csr);
  memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);

  pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
  pCsr->filter.flags |= FTS3_SEGMENT_SCAN;

  rc = sqlite3Fts3SegReaderCursor(pFts3, p->iIndex, FTS3_SEGCURSOR_ALL,
      pCsr->filter.zTerm, pCsr->filter.nTerm, 0, 1, &pCsr->csr
  );
  if( rc==SQLITE_OK ){
    rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
  }
  if( rc==SQLITE_OK ){
    rc = fts3termNextMethod(pCursor);

/*
** 2011 Jun 13
**
** 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 file is not part of the production FTS code. It is only used for
** testing. It contains a Tcl command that can be used to test if a document
** matches an FTS NEAR expression.
*/

#include <tcl.h>
#include <string.h>
#include <assert.h>

#define NM_MAX_TOKEN 12

typedef struct NearPhrase NearPhrase;
typedef struct NearDocument NearDocument;
typedef struct NearToken NearToken;

struct NearDocument {
  int nToken;                     /* Length of token in bytes */
  NearToken *aToken;              /* Token array */
};

struct NearToken {
  int n;                          /* Length of token in bytes */
  const char *z;                  /* Pointer to token string */
};

struct NearPhrase {
  int nNear;                      /* Preceding NEAR value */
  int nToken;                     /* Number of tokens in this phrase */
  NearToken aToken[NM_MAX_TOKEN]; /* Array of tokens in this phrase */
};

static int nm_phrase_match(
  NearPhrase *p,
  NearToken *aToken
){
  int ii;

  for(ii=0; ii<p->nToken; ii++){
    NearToken *pToken = &p->aToken[ii];
    if( pToken->n>0 && pToken->z[pToken->n-1]=='*' ){
      if( aToken[ii].n<(pToken->n-1) ) return 0;
      if( memcmp(aToken[ii].z, pToken->z, pToken->n-1) ) return 0;
    }else{
      if( aToken[ii].n!=pToken->n ) return 0;
      if( memcmp(aToken[ii].z, pToken->z, pToken->n) ) return 0;
    }
  }

  return 1;
}

static int nm_near_chain(
  int iDir,                       /* Direction to iterate through aPhrase[] */
  NearDocument *pDoc,             /* Document to match against */
  int iPos,                       /* Position at which iPhrase was found */
  int nPhrase,                    /* Size of phrase array */
  NearPhrase *aPhrase,            /* Phrase array */
  int iPhrase                     /* Index of phrase found */
){
  int iStart;
  int iStop;
  int ii;
  int nNear;
  int iPhrase2;
  NearPhrase *p;
  NearPhrase *pPrev;

  assert( iDir==1 || iDir==-1 );

  if( iDir==1 ){
    if( (iPhrase+1)==nPhrase ) return 1;
    nNear = aPhrase[iPhrase+1].nNear;
  }else{
    if( iPhrase==0 ) return 1;
    nNear = aPhrase[iPhrase].nNear;
  }
  pPrev = &aPhrase[iPhrase];
  iPhrase2 = iPhrase+iDir;
  p = &aPhrase[iPhrase2];

  iStart = iPos - nNear - p->nToken;
  iStop = iPos + nNear + pPrev->nToken;

  if( iStart<0 ) iStart = 0;
  if( iStop > pDoc->nToken - p->nToken ) iStop = pDoc->nToken - p->nToken;

  for(ii=iStart; ii<=iStop; ii++){
    if( nm_phrase_match(p, &pDoc->aToken[ii]) ){
      if( nm_near_chain(iDir, pDoc, ii, nPhrase, aPhrase, iPhrase2) ) return 1;
    }
  }

  return 0;
}

static int nm_match_count(
  NearDocument *pDoc,             /* Document to match against */
  int nPhrase,                    /* Size of phrase array */
  NearPhrase *aPhrase,            /* Phrase array */
  int iPhrase                     /* Index of phrase to count matches for */
){
  int nOcc = 0;
  int ii;
  NearPhrase *p = &aPhrase[iPhrase];

  for(ii=0; ii<(pDoc->nToken + 1 - p->nToken); ii++){
    if( nm_phrase_match(p, &pDoc->aToken[ii]) ){
      /* Test forward NEAR chain (i>iPhrase) */
      if( 0==nm_near_chain(1, pDoc, ii, nPhrase, aPhrase, iPhrase) ) continue;

      /* Test reverse NEAR chain (i<iPhrase) */
      if( 0==nm_near_chain(-1, pDoc, ii, nPhrase, aPhrase, iPhrase) ) continue;

      /* This is a real match. Increment the counter. */
      nOcc++;
    }
  } 

  return nOcc;
}

/*
** Tclcmd: fts3_near_match DOCUMENT EXPR ?OPTIONS?
*/
static int fts3_near_match_cmd(
  ClientData clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int nTotal = 0;
  int rc;
  int ii;
  int nPhrase;
  NearPhrase *aPhrase = 0;
  NearDocument doc = {0, 0};
  Tcl_Obj **apDocToken;
  Tcl_Obj *pRet;
  Tcl_Obj *pPhrasecount = 0;
  
  Tcl_Obj **apExprToken;
  int nExprToken;

  /* Must have 3 or more arguments. */
  if( objc<3 || (objc%2)==0 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DOCUMENT EXPR ?OPTION VALUE?...");
    rc = TCL_ERROR;
    goto near_match_out;
  }

  for(ii=3; ii<objc; ii+=2){
    enum NM_enum { NM_PHRASECOUNTS };
    struct TestnmSubcmd {
      char *zName;
      enum NM_enum eOpt;
    } aOpt[] = {
      { "-phrasecountvar", NM_PHRASECOUNTS },
      { 0, 0 }
    };
    int iOpt;
    if( Tcl_GetIndexFromObjStruct(
        interp, objv[ii], aOpt, sizeof(aOpt[0]), "option", 0, &iOpt) 
    ){
      return TCL_ERROR;
    }

    switch( aOpt[iOpt].eOpt ){
      case NM_PHRASECOUNTS:
        pPhrasecount = objv[ii+1];
        break;
    }
  }

  rc = Tcl_ListObjGetElements(interp, objv[1], &doc.nToken, &apDocToken);
  if( rc!=TCL_OK ) goto near_match_out;
  doc.aToken = (NearToken *)ckalloc(doc.nToken*sizeof(NearToken));
  for(ii=0; ii<doc.nToken; ii++){
    doc.aToken[ii].z = Tcl_GetStringFromObj(apDocToken[ii], &doc.aToken[ii].n);
  }

  rc = Tcl_ListObjGetElements(interp, objv[2], &nExprToken, &apExprToken);
  if( rc!=TCL_OK ) goto near_match_out;

  nPhrase = (nExprToken + 1) / 2;
  aPhrase = (NearPhrase *)ckalloc(nPhrase * sizeof(NearPhrase));
  memset(aPhrase, 0, nPhrase * sizeof(NearPhrase));
  for(ii=0; ii<nPhrase; ii++){
    Tcl_Obj *pPhrase = apExprToken[ii*2];
    Tcl_Obj **apToken;
    int nToken;
    int jj;

    rc = Tcl_ListObjGetElements(interp, pPhrase, &nToken, &apToken);
    if( rc!=TCL_OK ) goto near_match_out;
    if( nToken>NM_MAX_TOKEN ){
      Tcl_AppendResult(interp, "Too many tokens in phrase", 0);
      rc = TCL_ERROR;
      goto near_match_out;
    }
    for(jj=0; jj<nToken; jj++){
      NearToken *pT = &aPhrase[ii].aToken[jj];
      pT->z = Tcl_GetStringFromObj(apToken[jj], &pT->n);
    }
    aPhrase[ii].nToken = nToken;
  }
  for(ii=1; ii<nPhrase; ii++){
    Tcl_Obj *pNear = apExprToken[2*ii-1];
    int nNear;
    rc = Tcl_GetIntFromObj(interp, pNear, &nNear);
    if( rc!=TCL_OK ) goto near_match_out;
    aPhrase[ii].nNear = nNear;
  }

  pRet = Tcl_NewObj();
  Tcl_IncrRefCount(pRet);
  for(ii=0; ii<nPhrase; ii++){
    int nOcc = nm_match_count(&doc, nPhrase, aPhrase, ii);
    Tcl_ListObjAppendElement(interp, pRet, Tcl_NewIntObj(nOcc));
    nTotal += nOcc;
  }
  if( pPhrasecount ){
    Tcl_ObjSetVar2(interp, pPhrasecount, 0, pRet, 0);
  }
  Tcl_DecrRefCount(pRet);
  Tcl_SetObjResult(interp, Tcl_NewBooleanObj(nTotal>0));

 near_match_out: 
  ckfree((char *)aPhrase);
  ckfree((char *)doc.aToken);
  return rc;
}

int Sqlitetestfts3_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "fts3_near_match", fts3_near_match_cmd, 0, 0);
  return TCL_OK;
}

**
** This means that if we have a pointer into a buffer containing node data,
** it is always safe to read up to two varints from it without risking an
** overread, even if the node data is corrupted.
*/
#define FTS3_NODE_PADDING (FTS3_VARINT_MAX*2)

/*
** Under certain circumstances, b-tree nodes (doclists) can be loaded into
** memory incrementally instead of all at once. This can be a big performance
** win (reduced IO and CPU) if SQLite stops calling the virtual table xNext()
** method before retrieving all query results (as may happen, for example,
** if a query has a LIMIT clause).
**
** Incremental loading is used for b-tree nodes FTS3_NODE_CHUNK_THRESHOLD 
** bytes and larger. Nodes are loaded in chunks of FTS3_NODE_CHUNKSIZE bytes.
** The code is written so that the hard lower-limit for each of these values 
** is 1. Clearly such small values would be inefficient, but can be useful 
** for testing purposes.
**
** TODO: Add a test interface to modify these "constants" from a script for
** this purpose.
*/
#define FTS3_NODE_CHUNKSIZE (4*1024) 
#define FTS3_NODE_CHUNK_THRESHOLD (FTS3_NODE_CHUNKSIZE*4)
/* #define FTS3_NODE_CHUNKSIZE 1 */
/* #define FTS3_NODE_CHUNK_THRESHOLD 1 */

typedef struct PendingList PendingList;
typedef struct SegmentNode SegmentNode;
typedef struct SegmentWriter SegmentWriter;

/*


** An instance of the following data structure is used to build doclists
** incrementally. See function fts3PendingListAppend() for details.
*/
struct PendingList {
  int nData;
  char *aData;
  int nSpace;
  sqlite3_int64 iLastDocid;
  sqlite3_int64 iLastCol;

** a contiguous set of segment b-tree leaf nodes. Although the details of
** this structure are only manipulated by code in this file, opaque handles
** of type Fts3SegReader* are also used by code in fts3.c to iterate through
** terms when querying the full-text index. See functions:
**
**   sqlite3Fts3SegReaderNew()
**   sqlite3Fts3SegReaderFree()

**   sqlite3Fts3SegReaderIterate()
**
** Methods used to manipulate Fts3SegReader structures:
**
**   fts3SegReaderNext()
**   fts3SegReaderFirstDocid()
**   fts3SegReaderNextDocid()
*/
struct Fts3SegReader {
  int iIdx;                       /* Index within level, or 0x7FFFFFFF for PT */

  sqlite3_int64 iStartBlock;      /* Rowid of first leaf block to traverse */
  sqlite3_int64 iLeafEndBlock;    /* Rowid of final leaf block to traverse */
  sqlite3_int64 iEndBlock;        /* Rowid of final block in segment (or 0) */
  sqlite3_int64 iCurrentBlock;    /* Current leaf block (or 0) */

  char *aNode;                    /* Pointer to node data (or NULL) */
  int nNode;                      /* Size of buffer at aNode (or 0) */
  int nPopulate;                  /* If >0, bytes of buffer aNode[] loaded */
  sqlite3_blob *pBlob;            /* If not NULL, blob handle to read node */

  Fts3HashElem **ppNextElem;

  /* Variables set by fts3SegReaderNext(). These may be read directly
  ** by the caller. They are valid from the time SegmentReaderNew() returns
  ** until SegmentReaderNext() returns something other than SQLITE_OK
  ** (i.e. SQLITE_DONE).
  */
  int nTerm;                      /* Number of bytes in current term */
  char *zTerm;                    /* Pointer to current term */
  int nTermAlloc;                 /* Allocated size of zTerm buffer */
  char *aDoclist;                 /* Pointer to doclist of current entry */
  int nDoclist;                   /* Size of doclist in current entry */

  /* The following variables are used by fts3SegReaderNextDocid() to iterate 
  ** through the current doclist (aDoclist/nDoclist).
  */
  char *pOffsetList;
  int nOffsetList;                /* For descending pending seg-readers only */
  sqlite3_int64 iDocid;
};

#define fts3SegReaderIsPending(p) ((p)->ppNextElem!=0)
#define fts3SegReaderIsRootOnly(p) ((p)->aNode==(char *)&(p)[1])

/*

** the interior part of the segment b+-tree structures (everything except
** the leaf nodes). These functions and type are only ever used by code
** within the fts3SegWriterXXX() family of functions described above.
**
**   fts3NodeAddTerm()
**   fts3NodeWrite()
**   fts3NodeFree()
**
** When a b+tree is written to the database (either as a result of a merge
** or the pending-terms table being flushed), leaves are written into the 
** database file as soon as they are completely populated. The interior of
** the tree is assembled in memory and written out only once all leaves have
** been populated and stored. This is Ok, as the b+-tree fanout is usually
** very large, meaning that the interior of the tree consumes relatively 
** little memory.
*/
struct SegmentNode {
  SegmentNode *pParent;           /* Parent node (or NULL for root node) */
  SegmentNode *pRight;            /* Pointer to right-sibling */
  SegmentNode *pLeftmost;         /* Pointer to left-most node of this depth */
  int nEntry;                     /* Number of terms written to node so far */
  char *zTerm;                    /* Pointer to previous term buffer */

#define SQL_DELETE_ALL_STAT            6
#define SQL_SELECT_CONTENT_BY_ROWID    7
#define SQL_NEXT_SEGMENT_INDEX         8
#define SQL_INSERT_SEGMENTS            9
#define SQL_NEXT_SEGMENTS_ID          10
#define SQL_INSERT_SEGDIR             11
#define SQL_SELECT_LEVEL              12
#define SQL_SELECT_LEVEL_RANGE        13
#define SQL_SELECT_LEVEL_COUNT        14
#define SQL_SELECT_SEGDIR_MAX_LEVEL   15
#define SQL_DELETE_SEGDIR_LEVEL       16
#define SQL_DELETE_SEGMENTS_RANGE     17
#define SQL_CONTENT_INSERT            18
#define SQL_DELETE_DOCSIZE            19
#define SQL_REPLACE_DOCSIZE           20
#define SQL_SELECT_DOCSIZE            21
#define SQL_SELECT_DOCTOTAL           22
#define SQL_REPLACE_DOCTOTAL          23

#define SQL_SELECT_ALL_PREFIX_LEVEL   24
#define SQL_DELETE_ALL_TERMS_SEGDIR   25

#define SQL_DELETE_SEGDIR_RANGE       26

/*
** 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.
**

/* 10 */  "SELECT coalesce((SELECT max(blockid) FROM %Q.'%q_segments') + 1, 1)",
/* 11 */  "INSERT INTO %Q.'%q_segdir' VALUES(?,?,?,?,?,?)",

          /* Return segments in order from oldest to newest.*/ 
/* 12 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
            "FROM %Q.'%q_segdir' WHERE level = ? ORDER BY idx ASC",
/* 13 */  "SELECT idx, start_block, leaves_end_block, end_block, root "
            "FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?"
            "ORDER BY level DESC, idx ASC",

/* 14 */  "SELECT count(*) FROM %Q.'%q_segdir' WHERE level = ?",
/* 15 */  "SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",

/* 16 */  "DELETE FROM %Q.'%q_segdir' WHERE level = ?",
/* 17 */  "DELETE FROM %Q.'%q_segments' WHERE blockid BETWEEN ? AND ?",
/* 18 */  "INSERT INTO %Q.'%q_content' VALUES(%s)",
/* 19 */  "DELETE FROM %Q.'%q_docsize' WHERE docid = ?",
/* 20 */  "REPLACE INTO %Q.'%q_docsize' VALUES(?,?)",
/* 21 */  "SELECT size FROM %Q.'%q_docsize' WHERE docid=?",
/* 22 */  "SELECT value FROM %Q.'%q_stat' WHERE id=0",
/* 23 */  "REPLACE INTO %Q.'%q_stat' VALUES(0,?)",
/* 24 */  "",
/* 25 */  "",

/* 26 */ "DELETE FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?",

  };
  int rc = SQLITE_OK;
  sqlite3_stmt *pStmt;

  assert( SizeofArray(azSql)==SizeofArray(p->aStmt) );
  assert( eStmt<SizeofArray(azSql) && eStmt>=0 );
  

**
**   0: idx
**   1: start_block
**   2: leaves_end_block
**   3: end_block
**   4: root
*/
int sqlite3Fts3AllSegdirs(
  Fts3Table *p,                   /* FTS3 table */
  int iIndex,                     /* Index for p->aIndex[] */
  int iLevel,                     /* Level to select */
  sqlite3_stmt **ppStmt           /* OUT: Compiled statement */
){
  int rc;
  sqlite3_stmt *pStmt = 0;

  assert( iLevel==FTS3_SEGCURSOR_ALL || iLevel>=0 );
  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
  assert( iIndex>=0 && iIndex<p->nIndex );

  if( iLevel<0 ){
    /* "SELECT * FROM %_segdir WHERE level BETWEEN ? AND ? ORDER BY ..." */
    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL_RANGE, &pStmt, 0);
    if( rc==SQLITE_OK ){ 
      sqlite3_bind_int(pStmt, 1, iIndex*FTS3_SEGDIR_MAXLEVEL);
      sqlite3_bind_int(pStmt, 2, (iIndex+1)*FTS3_SEGDIR_MAXLEVEL-1);
    }
  }else{
    /* "SELECT * FROM %_segdir WHERE level = ? ORDER BY ..." */
    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
    if( rc==SQLITE_OK ){ 
      sqlite3_bind_int(pStmt, 1, iLevel+iIndex*FTS3_SEGDIR_MAXLEVEL);
    }
  }
  *ppStmt = pStmt;
  return rc;
}


/*

  *pRc = rc;
  if( p!=*pp ){
    *pp = p;
    return 1;
  }
  return 0;
}

/*
** Free a PendingList object allocated by fts3PendingListAppend().
*/
static void fts3PendingListDelete(PendingList *pList){
  sqlite3_free(pList);
}

/*
** Add an entry to one of the pending-terms hash tables.
*/
static int fts3PendingTermsAddOne(
  Fts3Table *p,
  int iCol,
  int iPos,
  Fts3Hash *pHash,                /* Pending terms hash table to add entry to */
  const char *zToken,
  int nToken
){
  PendingList *pList;
  int rc = SQLITE_OK;

  pList = (PendingList *)fts3HashFind(pHash, zToken, nToken);
  if( pList ){
    p->nPendingData -= (pList->nData + nToken + sizeof(Fts3HashElem));
  }
  if( fts3PendingListAppend(&pList, p->iPrevDocid, iCol, iPos, &rc) ){
    if( pList==fts3HashInsert(pHash, zToken, nToken, pList) ){
      /* Malloc failed while inserting the new entry. This can only 
      ** happen if there was no previous entry for this token.
      */
      assert( 0==fts3HashFind(pHash, zToken, nToken) );
      sqlite3_free(pList);
      rc = SQLITE_NOMEM;
    }
  }
  if( rc==SQLITE_OK ){
    p->nPendingData += (pList->nData + nToken + sizeof(Fts3HashElem));
  }
  return rc;
}

/*
** Tokenize the nul-terminated string zText and add all tokens to the
** pending-terms hash-table. The docid used is that currently stored in
** p->iPrevDocid, and the column is specified by argument iCol.
**
** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.

  }
  pCsr->pTokenizer = pTokenizer;

  xNext = pModule->xNext;
  while( SQLITE_OK==rc
      && SQLITE_OK==(rc = xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos))
  ){

    int i;
    if( iPos>=nWord ) nWord = iPos+1;

    /* Positions cannot be negative; we use -1 as a terminator internally.
    ** Tokens must have a non-zero length.
    */
    if( iPos<0 || !zToken || nToken<=0 ){
      rc = SQLITE_ERROR;
      break;
    }

    /* Add the term to the terms index */



    rc = fts3PendingTermsAddOne(




        p, iCol, iPos, &p->aIndex[0].hPending, zToken, nToken
    );

    

    /* Add the term to each of the prefix indexes that it is not too 
    ** short for. */
    for(i=1; rc==SQLITE_OK && i<p->nIndex; i++){
      struct Fts3Index *pIndex = &p->aIndex[i];
      if( nToken<pIndex->nPrefix ) continue;
      rc = fts3PendingTermsAddOne(
          p, iCol, iPos, &pIndex->hPending, zToken, pIndex->nPrefix
      );
    }
  }

  pModule->xClose(pCsr);
  *pnWord = nWord;
  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
}

    if( rc!=SQLITE_OK ) return rc;
  }
  p->iPrevDocid = iDocid;
  return SQLITE_OK;
}

/*
** Discard the contents of the pending-terms hash tables. 
*/
void sqlite3Fts3PendingTermsClear(Fts3Table *p){
  int i;
  for(i=0; i<p->nIndex; i++){
    Fts3HashElem *pElem;
    Fts3Hash *pHash = &p->aIndex[i].hPending;
    for(pElem=fts3HashFirst(pHash); pElem; pElem=fts3HashNext(pElem)){
      PendingList *pList = (PendingList *)fts3HashData(pElem);
      fts3PendingListDelete(pList);
    }
    fts3HashClear(pHash);
  }
  p->nPendingData = 0;
}

/*
** This function is called by the xUpdate() method as part of an INSERT
** operation. It adds entries for each term in the new record to the
** pendingTerms hash table.

  *pRC = rc;
}

/*
** Forward declaration to account for the circular dependency between
** functions fts3SegmentMerge() and fts3AllocateSegdirIdx().
*/
static int fts3SegmentMerge(Fts3Table *, int, int);

/* 
** This function allocates a new level iLevel index in the segdir table.
** Usually, indexes are allocated within a level sequentially starting
** with 0, so the allocated index is one greater than the value returned
** by:
**
**   SELECT max(idx) FROM %_segdir WHERE level = :iLevel
**
** However, if there are already FTS3_MERGE_COUNT indexes at the requested
** level, they are merged into a single level (iLevel+1) segment and the 
** allocated index is 0.
**
** If successful, *piIdx is set to the allocated index slot and SQLITE_OK
** returned. Otherwise, an SQLite error code is returned.
*/
static int fts3AllocateSegdirIdx(
  Fts3Table *p, 
  int iIndex,                     /* Index for p->aIndex */
  int iLevel, 
  int *piIdx
){
  int rc;                         /* Return Code */
  sqlite3_stmt *pNextIdx;         /* Query for next idx at level iLevel */
  int iNext = 0;                  /* Result of query pNextIdx */

  /* Set variable iNext to the next available segdir index at level iLevel. */
  rc = fts3SqlStmt(p, SQL_NEXT_SEGMENT_INDEX, &pNextIdx, 0);
  if( rc==SQLITE_OK ){
    sqlite3_bind_int(pNextIdx, 1, iIndex*FTS3_SEGDIR_MAXLEVEL + iLevel);
    if( SQLITE_ROW==sqlite3_step(pNextIdx) ){
      iNext = sqlite3_column_int(pNextIdx, 0);
    }
    rc = sqlite3_reset(pNextIdx);
  }

  if( rc==SQLITE_OK ){
    /* If iNext is FTS3_MERGE_COUNT, indicating that level iLevel is already
    ** full, merge all segments in level iLevel into a single iLevel+1
    ** segment and allocate (newly freed) index 0 at level iLevel. Otherwise,
    ** if iNext is less than FTS3_MERGE_COUNT, allocate index iNext.
    */
    if( iNext>=FTS3_MERGE_COUNT ){
      rc = fts3SegmentMerge(p, iIndex, iLevel);
      *piIdx = 0;
    }else{
      *piIdx = iNext;
    }
  }

  return rc;

** method (xFilter etc.) that may directly or indirectly call this function
** must call sqlite3Fts3SegmentsClose() before returning.
*/
int sqlite3Fts3ReadBlock(
  Fts3Table *p,                   /* FTS3 table handle */
  sqlite3_int64 iBlockid,         /* Access the row with blockid=$iBlockid */
  char **paBlob,                  /* OUT: Blob data in malloc'd buffer */
  int *pnBlob,                    /* OUT: Size of blob data */
  int *pnLoad                     /* OUT: Bytes actually loaded */
){
  int rc;                         /* Return code */

  /* pnBlob must be non-NULL. paBlob may be NULL or non-NULL. */
  assert( pnBlob);

  if( p->pSegments ){
    rc = sqlite3_blob_reopen(p->pSegments, iBlockid);
  }else{
    if( 0==p->zSegmentsTbl ){
      p->zSegmentsTbl = sqlite3_mprintf("%s_segments", p->zName);
      if( 0==p->zSegmentsTbl ) return SQLITE_NOMEM;
    }
    rc = sqlite3_blob_open(
       p->db, p->zDb, p->zSegmentsTbl, "block", iBlockid, 0, &p->pSegments
    );
  }

  if( rc==SQLITE_OK ){
    int nByte = sqlite3_blob_bytes(p->pSegments);
    *pnBlob = nByte;
    if( paBlob ){
      char *aByte = sqlite3_malloc(nByte + FTS3_NODE_PADDING);
      if( !aByte ){
        rc = SQLITE_NOMEM;
      }else{
        if( pnLoad && nByte>(FTS3_NODE_CHUNK_THRESHOLD) ){
          nByte = FTS3_NODE_CHUNKSIZE;
          *pnLoad = nByte;
        }
        rc = sqlite3_blob_read(p->pSegments, aByte, nByte, 0);
        memset(&aByte[nByte], 0, FTS3_NODE_PADDING);
        if( rc!=SQLITE_OK ){
          sqlite3_free(aByte);
          aByte = 0;
        }
      }
      *paBlob = aByte;
    }

  }

  return rc;
}

/*
** Close the blob handle at p->pSegments, if it is open. See comments above
** the sqlite3Fts3ReadBlock() function for details.
*/
void sqlite3Fts3SegmentsClose(Fts3Table *p){
  sqlite3_blob_close(p->pSegments);
  p->pSegments = 0;
}
    
static int fts3SegReaderIncrRead(Fts3SegReader *pReader){
  int nRead;                      /* Number of bytes to read */
  int rc;                         /* Return code */

  nRead = MIN(pReader->nNode - pReader->nPopulate, FTS3_NODE_CHUNKSIZE);
  rc = sqlite3_blob_read(
      pReader->pBlob, 
      &pReader->aNode[pReader->nPopulate],
      nRead,
      pReader->nPopulate
  );

  if( rc==SQLITE_OK ){
    pReader->nPopulate += nRead;
    memset(&pReader->aNode[pReader->nPopulate], 0, FTS3_NODE_PADDING);
    if( pReader->nPopulate==pReader->nNode ){
      sqlite3_blob_close(pReader->pBlob);
      pReader->pBlob = 0;
      pReader->nPopulate = 0;
    }
  }
  return rc;
}

static int fts3SegReaderRequire(Fts3SegReader *pReader, char *pFrom, int nByte){
  int rc = SQLITE_OK;
  assert( !pReader->pBlob 
       || (pFrom>=pReader->aNode && pFrom<&pReader->aNode[pReader->nNode])
  );
  while( pReader->pBlob && rc==SQLITE_OK 
     &&  (pFrom - pReader->aNode + nByte)>pReader->nPopulate
  ){
    rc = fts3SegReaderIncrRead(pReader);
  }
  return rc;
}

/*
** Move the iterator passed as the first argument to the next term in the
** segment. If successful, SQLITE_OK is returned. If there is no next term,
** SQLITE_DONE. Otherwise, an SQLite error code.
*/
static int fts3SegReaderNext(
  Fts3Table *p, 
  Fts3SegReader *pReader,
  int bIncr
){
  int rc;                         /* Return code of various sub-routines */
  char *pNext;                    /* Cursor variable */
  int nPrefix;                    /* Number of bytes in term prefix */
  int nSuffix;                    /* Number of bytes in term suffix */

  if( !pReader->aDoclist ){
    pNext = pReader->aNode;
  }else{
    pNext = &pReader->aDoclist[pReader->nDoclist];
  }

  if( !pNext || pNext>=&pReader->aNode[pReader->nNode] ){


    if( fts3SegReaderIsPending(pReader) ){
      Fts3HashElem *pElem = *(pReader->ppNextElem);
      if( pElem==0 ){
        pReader->aNode = 0;
      }else{
        PendingList *pList = (PendingList *)fts3HashData(pElem);
        pReader->zTerm = (char *)fts3HashKey(pElem);
        pReader->nTerm = fts3HashKeysize(pElem);
        pReader->nNode = pReader->nDoclist = pList->nData + 1;
        pReader->aNode = pReader->aDoclist = pList->aData;
        pReader->ppNextElem++;
        assert( pReader->aNode );
      }
      return SQLITE_OK;
    }

    if( !fts3SegReaderIsRootOnly(pReader) ){
      sqlite3_free(pReader->aNode);
      sqlite3_blob_close(pReader->pBlob);
      pReader->pBlob = 0;
    }
    pReader->aNode = 0;

    /* If iCurrentBlock>=iLeafEndBlock, this is an EOF condition. All leaf 
    ** blocks have already been traversed.  */
    assert( pReader->iCurrentBlock<=pReader->iLeafEndBlock );
    if( pReader->iCurrentBlock>=pReader->iLeafEndBlock ){
      return SQLITE_OK;
    }

    rc = sqlite3Fts3ReadBlock(
        p, ++pReader->iCurrentBlock, &pReader->aNode, &pReader->nNode, 
        (bIncr ? &pReader->nPopulate : 0)
    );
    if( rc!=SQLITE_OK ) return rc;
    assert( pReader->pBlob==0 );
    if( bIncr && pReader->nPopulate<pReader->nNode ){
      pReader->pBlob = p->pSegments;
      p->pSegments = 0;
    }
    pNext = pReader->aNode;
  }

  assert( !fts3SegReaderIsPending(pReader) );

  rc = fts3SegReaderRequire(pReader, pNext, FTS3_VARINT_MAX*2);
  if( rc!=SQLITE_OK ) return rc;
  
  /* Because of the FTS3_NODE_PADDING bytes of padding, the following is 
  ** safe (no risk of overread) even if the node data is corrupted. */

  pNext += sqlite3Fts3GetVarint32(pNext, &nPrefix);
  pNext += sqlite3Fts3GetVarint32(pNext, &nSuffix);
  if( nPrefix<0 || nSuffix<=0 
   || &pNext[nSuffix]>&pReader->aNode[pReader->nNode] 
  ){
    return SQLITE_CORRUPT_VTAB;
  }

  if( nPrefix+nSuffix>pReader->nTermAlloc ){
    int nNew = (nPrefix+nSuffix)*2;
    char *zNew = sqlite3_realloc(pReader->zTerm, nNew);
    if( !zNew ){
      return SQLITE_NOMEM;
    }
    pReader->zTerm = zNew;
    pReader->nTermAlloc = nNew;
  }

  rc = fts3SegReaderRequire(pReader, pNext, nSuffix+FTS3_VARINT_MAX);
  if( rc!=SQLITE_OK ) return rc;

  memcpy(&pReader->zTerm[nPrefix], pNext, nSuffix);
  pReader->nTerm = nPrefix+nSuffix;
  pNext += nSuffix;
  pNext += sqlite3Fts3GetVarint32(pNext, &pReader->nDoclist);
  pReader->aDoclist = pNext;
  pReader->pOffsetList = 0;

  /* Check that the doclist does not appear to extend past the end of the
  ** b-tree node. And that the final byte of the doclist is 0x00. If either 
  ** of these statements is untrue, then the data structure is corrupt.
  */
  if( &pReader->aDoclist[pReader->nDoclist]>&pReader->aNode[pReader->nNode] 
   || (pReader->nPopulate==0 && pReader->aDoclist[pReader->nDoclist-1])
  ){
    return SQLITE_CORRUPT_VTAB;
  }
  return SQLITE_OK;
}

/*
** Set the SegReader to point to the first docid in the doclist associated
** with the current term.
*/
static int fts3SegReaderFirstDocid(Fts3Table *pTab, Fts3SegReader *pReader){
  int rc = SQLITE_OK;
  assert( pReader->aDoclist );
  assert( !pReader->pOffsetList );
  if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
    u8 bEof = 0;
    pReader->iDocid = 0;
    pReader->nOffsetList = 0;
    sqlite3Fts3DoclistPrev(0,
        pReader->aDoclist, pReader->nDoclist, &pReader->pOffsetList, 
        &pReader->iDocid, &pReader->nOffsetList, &bEof
    );
  }else{
    rc = fts3SegReaderRequire(pReader, pReader->aDoclist, FTS3_VARINT_MAX);
    if( rc==SQLITE_OK ){
      int n = sqlite3Fts3GetVarint(pReader->aDoclist, &pReader->iDocid);
      pReader->pOffsetList = &pReader->aDoclist[n];
    }
  }
  return rc;
}

/*
** Advance the SegReader to point to the next docid in the doclist
** associated with the current term.
** 
** If arguments ppOffsetList and pnOffsetList are not NULL, then 
** *ppOffsetList is set to point to the first column-offset list
** in the doclist entry (i.e. immediately past the docid varint).
** *pnOffsetList is set to the length of the set of column-offset
** lists, not including the nul-terminator byte. For example:
*/
static int fts3SegReaderNextDocid(
  Fts3Table *pTab,
  Fts3SegReader *pReader,         /* Reader to advance to next docid */
  char **ppOffsetList,            /* OUT: Pointer to current position-list */
  int *pnOffsetList               /* OUT: Length of *ppOffsetList in bytes */
){
  int rc = SQLITE_OK;
  char *p = pReader->pOffsetList;
  char c = 0;






  assert( p );

  if( pTab->bDescIdx && fts3SegReaderIsPending(pReader) ){
    /* A pending-terms seg-reader for an FTS4 table that uses order=desc.
    ** Pending-terms doclists are always built up in ascending order, so
    ** we have to iterate through them backwards here. */
    u8 bEof = 0;

    if( ppOffsetList ){
      *ppOffsetList = pReader->pOffsetList;
      *pnOffsetList = pReader->nOffsetList - 1;
    }
    sqlite3Fts3DoclistPrev(0,
        pReader->aDoclist, pReader->nDoclist, &p, &pReader->iDocid,
        &pReader->nOffsetList, &bEof
    );
    if( bEof ){
      pReader->pOffsetList = 0;
    }else{


      pReader->pOffsetList = p;
    }
  }else{

    /* Pointer p currently points at the first byte of an offset list. The
    ** following block advances it to point one byte past the end of
    ** the same offset list. */
    while( 1 ){
  
      /* The following line of code (and the "p++" below the while() loop) is
      ** normally all that is required to move pointer p to the desired 
      ** position. The exception is if this node is being loaded from disk
      ** incrementally and pointer "p" now points to the first byte passed
      ** the populated part of pReader->aNode[].
      */
      while( *p | c ) c = *p++ & 0x80;
      assert( *p==0 );
  
      if( pReader->pBlob==0 || p<&pReader->aNode[pReader->nPopulate] ) break;
      rc = fts3SegReaderIncrRead(pReader);
      if( rc!=SQLITE_OK ) return rc;
    }
    p++;
  
    /* If required, populate the output variables with a pointer to and the
    ** size of the previous offset-list.
    */
    if( ppOffsetList ){
      *ppOffsetList = pReader->pOffsetList;
      *pnOffsetList = (int)(p - pReader->pOffsetList - 1);
    }
  
    /* 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{
      rc = fts3SegReaderRequire(pReader, p, FTS3_VARINT_MAX);
      if( rc==SQLITE_OK ){
        sqlite3_int64 iDelta;
        pReader->pOffsetList = p + sqlite3Fts3GetVarint(p, &iDelta);
        if( pTab->bDescIdx ){
          pReader->iDocid -= iDelta;
        }else{
          pReader->iDocid += iDelta;
        }
      }
    }
  }

  return SQLITE_OK;
}









int sqlite3Fts3MsrOvfl(
  Fts3Cursor *pCsr, 
  Fts3MultiSegReader *pMsr,
  int *pnOvfl
){
  Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
  int nOvfl = 0;
  int ii;
  int rc = SQLITE_OK;

  int pgsz = p->nPgsz;





  assert( p->bHasStat );
  assert( pgsz>0 );

  for(ii=0; rc==SQLITE_OK && ii<pMsr->nSegment; ii++){
    Fts3SegReader *pReader = pMsr->apSegment[ii];
    if( !fts3SegReaderIsPending(pReader) 
     && !fts3SegReaderIsRootOnly(pReader) 
    ){
      int jj;

      for(jj=pReader->iStartBlock; jj<=pReader->iLeafEndBlock; jj++){

















        int nBlob;
        rc = sqlite3Fts3ReadBlock(p, jj, 0, &nBlob, 0);


























        if( rc!=SQLITE_OK ) break;
        if( (nBlob+35)>pgsz ){
          nOvfl += (nBlob + 34)/pgsz;

        }
      }
    }
  }
  *pnOvfl = nOvfl;
  return rc;
}

/*
** Free all allocations associated with the iterator passed as the 
** second argument.
*/
void sqlite3Fts3SegReaderFree(Fts3SegReader *pReader){
  if( pReader && !fts3SegReaderIsPending(pReader) ){
    sqlite3_free(pReader->zTerm);
    if( !fts3SegReaderIsRootOnly(pReader) ){
      sqlite3_free(pReader->aNode);
      sqlite3_blob_close(pReader->pBlob);
    }
  }
  sqlite3_free(pReader);
}

/*
** Allocate a new SegReader object.

  }
  return c;
}

/*
** This function is used to allocate an Fts3SegReader that iterates through
** a subset of the terms stored in the Fts3Table.pendingTerms array.
**
** If the isPrefixIter parameter is zero, then the returned SegReader iterates
** through each term in the pending-terms table. Or, if isPrefixIter is
** non-zero, it iterates through each term and its prefixes. For example, if
** the pending terms hash table contains the terms "sqlite", "mysql" and
** "firebird", then the iterator visits the following 'terms' (in the order
** shown):
**
**   f fi fir fire fireb firebi firebir firebird
**   m my mys mysq mysql
**   s sq sql sqli sqlit sqlite
**
** Whereas if isPrefixIter is zero, the terms visited are:
**
**   firebird mysql sqlite
*/
int sqlite3Fts3SegReaderPending(
  Fts3Table *p,                   /* Virtual table handle */
  int iIndex,                     /* Index for p->aIndex */
  const char *zTerm,              /* Term to search for */
  int nTerm,                      /* Size of buffer zTerm */
  int bPrefix,                    /* True for a prefix iterator */
  Fts3SegReader **ppReader        /* OUT: SegReader for pending-terms */
){
  Fts3SegReader *pReader = 0;     /* Fts3SegReader object to return */
  Fts3HashElem **aElem = 0;       /* Array of term hash entries to scan */
  int nElem = 0;                  /* Size of array at aElem */
  int rc = SQLITE_OK;             /* Return Code */
  Fts3Hash *pHash;

  pHash = &p->aIndex[iIndex].hPending;
  if( bPrefix ){
    int nAlloc = 0;               /* Size of allocated array at aElem */
    Fts3HashElem *pE = 0;         /* Iterator variable */

    for(pE=fts3HashFirst(pHash); pE; pE=fts3HashNext(pE)){
      char *zKey = (char *)fts3HashKey(pE);
      int nKey = fts3HashKeysize(pE);
      if( nTerm==0 || (nKey>=nTerm && 0==memcmp(zKey, zTerm, nTerm)) ){
        if( nElem==nAlloc ){
          Fts3HashElem **aElem2;
          nAlloc += 16;
          aElem2 = (Fts3HashElem **)sqlite3_realloc(
              aElem, nAlloc*sizeof(Fts3HashElem *)
          );
          if( !aElem2 ){
            rc = SQLITE_NOMEM;
            nElem = 0;
            break;
          }
          aElem = aElem2;
        }

        aElem[nElem++] = pE;
      }
    }

    /* If more than one term matches the prefix, sort the Fts3HashElem
    ** objects in term order using qsort(). This uses the same comparison
    ** callback as is used when flushing terms to disk.
    */
    if( nElem>1 ){
      qsort(aElem, nElem, sizeof(Fts3HashElem *), fts3CompareElemByTerm);
    }

  }else{
    /* The query is a simple term lookup that matches at most one term in
    ** the index. All that is required is a straight hash-lookup. */
    Fts3HashElem *pE = fts3HashFindElem(pHash, zTerm, nTerm);
    if( pE ){
      aElem = &pE;
      nElem = 1;
    }
  }

  if( nElem>0 ){
    int nByte = sizeof(Fts3SegReader) + (nElem+1)*sizeof(Fts3HashElem *);
    pReader = (Fts3SegReader *)sqlite3_malloc(nByte);
    if( !pReader ){
      rc = SQLITE_NOMEM;
    }else{
      memset(pReader, 0, nByte);
      pReader->iIdx = 0x7FFFFFFF;
      pReader->ppNextElem = (Fts3HashElem **)&pReader[1];
      memcpy(pReader->ppNextElem, aElem, nElem*sizeof(Fts3HashElem *));
    }
  }

  if( bPrefix ){
    sqlite3_free(aElem);
  }
  *ppReader = pReader;
  return rc;
}

/*

  int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
  if( rc==0 ){
    if( pLhs->iDocid==pRhs->iDocid ){
      rc = pRhs->iIdx - pLhs->iIdx;
    }else{
      rc = (pLhs->iDocid > pRhs->iDocid) ? 1 : -1;
    }
  }
  assert( pLhs->aNode && pRhs->aNode );
  return rc;
}
static int fts3SegReaderDoclistCmpRev(Fts3SegReader *pLhs, Fts3SegReader *pRhs){
  int rc = (pLhs->pOffsetList==0)-(pRhs->pOffsetList==0);
  if( rc==0 ){
    if( pLhs->iDocid==pRhs->iDocid ){
      rc = pRhs->iIdx - pLhs->iIdx;
    }else{
      rc = (pLhs->iDocid < pRhs->iDocid) ? 1 : -1;
    }
  }
  assert( pLhs->aNode && pRhs->aNode );
  return rc;
}

/*
** Compare the term that the Fts3SegReader object passed as the first argument

    }
    rc = sqlite3_reset(pStmt);
  }
  return rc;
}

/*

** Set *pnMax to the largest segment level in the database for the index
** iIndex.
**
** Segment levels are stored in the 'level' column of the %_segdir table.
**
** Return SQLITE_OK if successful, or an SQLite error code if not.
*/
static int fts3SegmentMaxLevel(Fts3Table *p, int iIndex, int *pnMax){
  sqlite3_stmt *pStmt;
  int rc;
  assert( iIndex>=0 && iIndex<p->nIndex );

  /* Set pStmt to the compiled version of:
  **
  **   SELECT max(level) FROM %Q.'%q_segdir' WHERE level BETWEEN ? AND ?
  **
  ** (1024 is actually the value of macro FTS3_SEGDIR_PREFIXLEVEL_STR).
  */
  rc = fts3SqlStmt(p, SQL_SELECT_SEGDIR_MAX_LEVEL, &pStmt, 0);
  if( rc!=SQLITE_OK ) return rc;
  sqlite3_bind_int(pStmt, 1, iIndex*FTS3_SEGDIR_MAXLEVEL);
  sqlite3_bind_int(pStmt, 2, (iIndex+1)*FTS3_SEGDIR_MAXLEVEL - 1);
  if( SQLITE_ROW==sqlite3_step(pStmt) ){

    *pnMax = sqlite3_column_int(pStmt, 0);
  }
  return sqlite3_reset(pStmt);
}

/*
** This function is used after merging multiple segments into a single large
** segment to delete the old, now redundant, segment b-trees. Specifically,
** it:
** 
**   1) Deletes all %_segments entries for the segments associated with 
**      each of the SegReader objects in the array passed as the third 
**      argument, and
**
**   2) deletes all %_segdir entries with level iLevel, or all %_segdir
**      entries regardless of level if (iLevel<0).
**
** SQLITE_OK is returned if successful, otherwise an SQLite error code.
*/
static int fts3DeleteSegdir(
  Fts3Table *p,                   /* Virtual table handle */
  int iIndex,                     /* Index for p->aIndex */
  int iLevel,                     /* Level of %_segdir entries to delete */
  Fts3SegReader **apSegment,      /* Array of SegReader objects */
  int nReader                     /* Size of array apSegment */
){
  int rc;                         /* Return Code */
  int i;                          /* Iterator variable */
  sqlite3_stmt *pDelete;          /* SQL statement to delete rows */

      rc = sqlite3_reset(pDelete);
    }
  }
  if( rc!=SQLITE_OK ){
    return rc;
  }

  assert( iLevel>=0 || iLevel==FTS3_SEGCURSOR_ALL );
  if( iLevel==FTS3_SEGCURSOR_ALL ){
    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_RANGE, &pDelete, 0);
    if( rc==SQLITE_OK ){
      sqlite3_bind_int(pDelete, 1, iIndex*FTS3_SEGDIR_MAXLEVEL);
      sqlite3_bind_int(pDelete, 2, (iIndex+1) * FTS3_SEGDIR_MAXLEVEL - 1);
    }
  }else{

    rc = fts3SqlStmt(p, SQL_DELETE_SEGDIR_LEVEL, &pDelete, 0);
    if( rc==SQLITE_OK ){
      sqlite3_bind_int(pDelete, 1, iIndex*FTS3_SEGDIR_MAXLEVEL + iLevel);
    }
  }

  if( rc==SQLITE_OK ){
    sqlite3_step(pDelete);
    rc = sqlite3_reset(pDelete);
  }


  return rc;
}

/*
** When this function is called, buffer *ppList (size *pnList bytes) contains 
** a position list that may (or may not) feature multiple columns. This

    p = &pList[1];
    p += sqlite3Fts3GetVarint32(p, &iCurrent);
  }

  *ppList = pList;
  *pnList = nList;
}

int sqlite3Fts3MsrIncrStart(
  Fts3Table *p,                   /* Virtual table handle */
  Fts3MultiSegReader *pCsr,       /* Cursor object */
  int iCol,                       /* Column to match on. */
  const char *zTerm,              /* Term to iterate through a doclist for */
  int nTerm                       /* Number of bytes in zTerm */
){
  int i;
  int nSegment = pCsr->nSegment;
  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
  );

  assert( pCsr->pFilter==0 );
  assert( zTerm && nTerm>0 );

  /* Advance each segment iterator until it points to the term zTerm/nTerm. */
  for(i=0; i<nSegment; i++){
    Fts3SegReader *pSeg = pCsr->apSegment[i];
    do {
      int rc = fts3SegReaderNext(p, pSeg, 1);
      if( rc!=SQLITE_OK ) return rc;
    }while( fts3SegReaderTermCmp(pSeg, zTerm, nTerm)<0 );
  }
  fts3SegReaderSort(pCsr->apSegment, nSegment, nSegment, fts3SegReaderCmp);

  /* Determine how many of the segments actually point to zTerm/nTerm. */
  for(i=0; i<nSegment; i++){
    Fts3SegReader *pSeg = pCsr->apSegment[i];
    if( !pSeg->aNode || fts3SegReaderTermCmp(pSeg, zTerm, nTerm) ){
      break;
    }
  }
  pCsr->nAdvance = i;

  /* Advance each of the segments to point to the first docid. */
  for(i=0; i<pCsr->nAdvance; i++){
    int rc = fts3SegReaderFirstDocid(p, pCsr->apSegment[i]);
    if( rc!=SQLITE_OK ) return rc;
  }
  fts3SegReaderSort(pCsr->apSegment, i, i, xCmp);

  assert( iCol<0 || iCol<p->nColumn );
  pCsr->iColFilter = iCol;

  return SQLITE_OK;
}

int sqlite3Fts3MsrIncrNext(
  Fts3Table *p,                   /* Virtual table handle */
  Fts3MultiSegReader *pMsr,       /* Multi-segment-reader handle */
  sqlite3_int64 *piDocid,         /* OUT: Docid value */
  char **paPoslist,               /* OUT: Pointer to position list */
  int *pnPoslist                  /* OUT: Size of position list in bytes */
){
  int nMerge = pMsr->nAdvance;
  Fts3SegReader **apSegment = pMsr->apSegment;
  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
  );

  if( nMerge==0 ){
    *paPoslist = 0;
    return SQLITE_OK;
  }

  while( 1 ){
    Fts3SegReader *pSeg;
    pSeg = pMsr->apSegment[0];

    if( pSeg->pOffsetList==0 ){
      *paPoslist = 0;
      break;
    }else{
      int rc;
      char *pList;
      int nList;
      int j;
      sqlite3_int64 iDocid = apSegment[0]->iDocid;

      rc = fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
      j = 1;
      while( rc==SQLITE_OK 
        && j<nMerge
        && apSegment[j]->pOffsetList
        && apSegment[j]->iDocid==iDocid
      ){
        rc = fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
        j++;
      }
      if( rc!=SQLITE_OK ) return rc;
      fts3SegReaderSort(pMsr->apSegment, nMerge, j, xCmp);

      if( pMsr->iColFilter>=0 ){
        fts3ColumnFilter(pMsr->iColFilter, &pList, &nList);
      }

      if( nList>0 ){
        *piDocid = iDocid;
        *paPoslist = pList;
        *pnPoslist = nList;
        break;
      }
    }
    
  }

  return SQLITE_OK;
}

int sqlite3Fts3SegReaderStart(
  Fts3Table *p,                   /* Virtual table handle */
  Fts3MultiSegReader *pCsr,       /* Cursor object */
  Fts3SegFilter *pFilter          /* Restrictions on range of iteration */
){
  int i;

  /* Initialize the cursor object */
  pCsr->pFilter = pFilter;

  /* If the Fts3SegFilter defines a specific term (or term prefix) to search 
  ** for, then advance each segment iterator until it points to a term of
  ** equal or greater value than the specified term. This prevents many
  ** unnecessary merge/sort operations for the case where single segment
  ** b-tree leaf nodes contain more than one term.
  */
  for(i=0; i<pCsr->nSegment; i++){
    int nTerm = pFilter->nTerm;
    const char *zTerm = pFilter->zTerm;
    Fts3SegReader *pSeg = pCsr->apSegment[i];
    do {
      int rc = fts3SegReaderNext(p, pSeg, 0);
      if( rc!=SQLITE_OK ) return rc;
    }while( zTerm && fts3SegReaderTermCmp(pSeg, zTerm, nTerm)<0 );
  }
  fts3SegReaderSort(
      pCsr->apSegment, pCsr->nSegment, pCsr->nSegment, fts3SegReaderCmp);

  return SQLITE_OK;
}

int sqlite3Fts3SegReaderStep(
  Fts3Table *p,                   /* Virtual table handle */
  Fts3MultiSegReader *pCsr        /* Cursor object */
){
  int rc = SQLITE_OK;

  int isIgnoreEmpty =  (pCsr->pFilter->flags & FTS3_SEGMENT_IGNORE_EMPTY);
  int isRequirePos =   (pCsr->pFilter->flags & FTS3_SEGMENT_REQUIRE_POS);
  int isColFilter =    (pCsr->pFilter->flags & FTS3_SEGMENT_COLUMN_FILTER);
  int isPrefix =       (pCsr->pFilter->flags & FTS3_SEGMENT_PREFIX);
  int isScan =         (pCsr->pFilter->flags & FTS3_SEGMENT_SCAN);

  Fts3SegReader **apSegment = pCsr->apSegment;
  int nSegment = pCsr->nSegment;
  Fts3SegFilter *pFilter = pCsr->pFilter;
  int (*xCmp)(Fts3SegReader *, Fts3SegReader *) = (
    p->bDescIdx ? fts3SegReaderDoclistCmpRev : fts3SegReaderDoclistCmp
  );

  if( pCsr->nSegment==0 ) return SQLITE_OK;

  do {
    int nMerge;
    int i;
  
    /* Advance the first pCsr->nAdvance entries in the apSegment[] array
    ** forward. Then sort the list in order of current term again.  
    */
    for(i=0; i<pCsr->nAdvance; i++){
      rc = fts3SegReaderNext(p, apSegment[i], 0);
      if( rc!=SQLITE_OK ) return rc;
    }
    fts3SegReaderSort(apSegment, nSegment, pCsr->nAdvance, fts3SegReaderCmp);
    pCsr->nAdvance = 0;

    /* If all the seg-readers are at EOF, we're finished. return SQLITE_OK. */
    assert( rc==SQLITE_OK );

        && apSegment[nMerge]->nTerm==pCsr->nTerm 
        && 0==memcmp(pCsr->zTerm, apSegment[nMerge]->zTerm, pCsr->nTerm)
    ){
      nMerge++;
    }

    assert( isIgnoreEmpty || (isRequirePos && !isColFilter) );
    if( nMerge==1 
     && !isIgnoreEmpty 
     && (p->bDescIdx==0 || fts3SegReaderIsPending(apSegment[0])==0)
    ){
      pCsr->aDoclist = apSegment[0]->aDoclist;
      pCsr->nDoclist = apSegment[0]->nDoclist;
      rc = SQLITE_ROW;
    }else{
      int nDoclist = 0;           /* Size of doclist */
      sqlite3_int64 iPrev = 0;    /* Previous docid stored in doclist */

      /* The current term of the first nMerge entries in the array
      ** of Fts3SegReader objects is the same. The doclists must be merged
      ** and a single term returned with the merged doclist.
      */
      for(i=0; i<nMerge; i++){
        fts3SegReaderFirstDocid(p, apSegment[i]);
      }
      fts3SegReaderSort(apSegment, nMerge, nMerge, xCmp);
      while( apSegment[0]->pOffsetList ){
        int j;                    /* Number of segments that share a docid */
        char *pList;
        int nList;
        int nByte;
        sqlite3_int64 iDocid = apSegment[0]->iDocid;
        fts3SegReaderNextDocid(p, apSegment[0], &pList, &nList);
        j = 1;
        while( j<nMerge
            && apSegment[j]->pOffsetList
            && apSegment[j]->iDocid==iDocid
        ){
          fts3SegReaderNextDocid(p, apSegment[j], 0, 0);
          j++;
        }

        if( isColFilter ){
          fts3ColumnFilter(pFilter->iCol, &pList, &nList);
        }

        if( !isIgnoreEmpty || nList>0 ){

          /* Calculate the 'docid' delta value to write into the merged 
          ** doclist. */
          sqlite3_int64 iDelta;
          if( p->bDescIdx && nDoclist>0 ){
            iDelta = iPrev - iDocid;
          }else{
            iDelta = iDocid - iPrev;
          }
          assert( iDelta>0 || (nDoclist==0 && iDelta==iDocid) );
          assert( nDoclist>0 || iDelta==iDocid );

          nByte = sqlite3Fts3VarintLen(iDelta) + (isRequirePos?nList+1:0);
          if( nDoclist+nByte>pCsr->nBuffer ){
            char *aNew;
            pCsr->nBuffer = (nDoclist+nByte)*2;
            aNew = sqlite3_realloc(pCsr->aBuffer, pCsr->nBuffer);
            if( !aNew ){
              return SQLITE_NOMEM;
            }
            pCsr->aBuffer = aNew;
          }
          nDoclist += sqlite3Fts3PutVarint(&pCsr->aBuffer[nDoclist], iDelta);


          iPrev = iDocid;
          if( isRequirePos ){
            memcpy(&pCsr->aBuffer[nDoclist], pList, nList);
            nDoclist += nList;
            pCsr->aBuffer[nDoclist++] = '\0';
          }
        }

        fts3SegReaderSort(apSegment, nMerge, j, xCmp);
      }
      if( nDoclist>0 ){
        pCsr->aDoclist = pCsr->aBuffer;
        pCsr->nDoclist = nDoclist;
        rc = SQLITE_ROW;
      }
    }
    pCsr->nAdvance = nMerge;
  }while( rc==SQLITE_OK );

  return rc;
}


void sqlite3Fts3SegReaderFinish(
  Fts3MultiSegReader *pCsr       /* Cursor object */
){
  if( pCsr ){
    int i;
    for(i=0; i<pCsr->nSegment; i++){
      sqlite3Fts3SegReaderFree(pCsr->apSegment[i]);
    }
    sqlite3_free(pCsr->apSegment);

** currently present in the database.
**
** If this function is called with iLevel<0, but there is only one
** segment in the database, SQLITE_DONE is returned immediately. 
** Otherwise, if successful, SQLITE_OK is returned. If an error occurs, 
** an SQLite error code is returned.
*/
static int fts3SegmentMerge(Fts3Table *p, int iIndex, int iLevel){
  int rc;                         /* Return code */
  int iIdx = 0;                   /* Index of new segment */
  int iNewLevel = 0;              /* Level/index to create new segment at */
  SegmentWriter *pWriter = 0;     /* Used to write the new, merged, segment */
  Fts3SegFilter filter;           /* Segment term filter condition */
  Fts3MultiSegReader csr;        /* Cursor to iterate through level(s) */
  int bIgnoreEmpty = 0;           /* True to ignore empty segments */

  assert( iLevel==FTS3_SEGCURSOR_ALL
       || iLevel==FTS3_SEGCURSOR_PENDING
       || iLevel>=0
  );
  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
  assert( iIndex>=0 && iIndex<p->nIndex );

  rc = sqlite3Fts3SegReaderCursor(p, iIndex, iLevel, 0, 0, 1, 0, &csr);
  if( rc!=SQLITE_OK || csr.nSegment==0 ) goto finished;

  if( iLevel==FTS3_SEGCURSOR_ALL ){
    /* This call is to merge all segments in the database to a single
    ** segment. The level of the new segment is equal to the the numerically 
    ** greatest segment level currently present in the database for this
    ** index. The idx of the new segment is always 0.  */

    if( csr.nSegment==1 ){
      rc = SQLITE_DONE;
      goto finished;
    }
    rc = fts3SegmentMaxLevel(p, iIndex, &iNewLevel);
    bIgnoreEmpty = 1;

  }else if( iLevel==FTS3_SEGCURSOR_PENDING ){
    iNewLevel = iIndex * FTS3_SEGDIR_MAXLEVEL; 
    rc = fts3AllocateSegdirIdx(p, iIndex, 0, &iIdx);
  }else{
    /* This call is to merge all segments at level iLevel. find the next
    ** available segment index at level iLevel+1. The call to
    ** fts3AllocateSegdirIdx() will merge the segments at level iLevel+1 to 
    ** a single iLevel+2 segment if necessary.  */

    rc = fts3AllocateSegdirIdx(p, iIndex, iLevel+1, &iIdx);
    iNewLevel = iIndex * FTS3_SEGDIR_MAXLEVEL + iLevel+1;
  }
  if( rc!=SQLITE_OK ) goto finished;
  assert( csr.nSegment>0 );
  assert( iNewLevel>=(iIndex*FTS3_SEGDIR_MAXLEVEL) );
  assert( iNewLevel<((iIndex+1)*FTS3_SEGDIR_MAXLEVEL) );

  memset(&filter, 0, sizeof(Fts3SegFilter));
  filter.flags = FTS3_SEGMENT_REQUIRE_POS;
  filter.flags |= (bIgnoreEmpty ? FTS3_SEGMENT_IGNORE_EMPTY : 0);

  rc = sqlite3Fts3SegReaderStart(p, &csr, &filter);
  while( SQLITE_OK==rc ){
    rc = sqlite3Fts3SegReaderStep(p, &csr);
    if( rc!=SQLITE_ROW ) break;
    rc = fts3SegWriterAdd(p, &pWriter, 1, 
        csr.zTerm, csr.nTerm, csr.aDoclist, csr.nDoclist);
  }
  if( rc!=SQLITE_OK ) goto finished;
  assert( pWriter );

  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
    rc = fts3DeleteSegdir(p, iIndex, iLevel, csr.apSegment, csr.nSegment);
    if( rc!=SQLITE_OK ) goto finished;
  }
  rc = fts3SegWriterFlush(p, pWriter, iNewLevel, iIdx);

 finished:
  fts3SegWriterFree(pWriter);
  sqlite3Fts3SegReaderFinish(&csr);
  return rc;
}


/* 
** 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, i, FTS3_SEGCURSOR_PENDING);
    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
  }
  sqlite3Fts3PendingTermsClear(p);
  return rc;
}

/*
** Encode N integers as varints into a blob.
*/
static void fts3EncodeIntArray(
  int N,             /* The number of integers to encode */

    return;
  }
  sqlite3_bind_blob(pStmt, 1, pBlob, nBlob, SQLITE_STATIC);
  sqlite3_step(pStmt);
  *pRC = sqlite3_reset(pStmt);
  sqlite3_free(a);
}

static int fts3DoOptimize(Fts3Table *p, int bReturnDone){
  int i;
  int bSeenDone = 0;
  int rc = SQLITE_OK;
  for(i=0; rc==SQLITE_OK && i<p->nIndex; i++){
    rc = fts3SegmentMerge(p, i, FTS3_SEGCURSOR_ALL);
    if( rc==SQLITE_DONE ){
      bSeenDone = 1;
      rc = SQLITE_OK;
    }
  }
  sqlite3Fts3SegmentsClose(p);
  sqlite3Fts3PendingTermsClear(p);

  return (rc==SQLITE_OK && bReturnDone && bSeenDone) ? SQLITE_DONE : rc;
}

/*
** Handle a 'special' INSERT of the form:
**
**   "INSERT INTO tbl(tbl) VALUES(<expr>)"
**
** Argument pVal contains the result of <expr>. Currently the only 
** meaningful value to insert is the text 'optimize'.
*/
static int fts3SpecialInsert(Fts3Table *p, sqlite3_value *pVal){
  int rc;                         /* Return Code */
  const char *zVal = (const char *)sqlite3_value_text(pVal);
  int nVal = sqlite3_value_bytes(pVal);

  if( !zVal ){
    return SQLITE_NOMEM;
  }else if( nVal==8 && 0==sqlite3_strnicmp(zVal, "optimize", 8) ){
    rc = fts3DoOptimize(p, 0);





#ifdef SQLITE_TEST
  }else if( nVal>9 && 0==sqlite3_strnicmp(zVal, "nodesize=", 9) ){
    p->nNodeSize = atoi(&zVal[9]);
    rc = SQLITE_OK;
  }else if( nVal>11 && 0==sqlite3_strnicmp(zVal, "maxpending=", 9) ){
    p->nMaxPendingData = atoi(&zVal[11]);
    rc = SQLITE_OK;
#endif
  }else{
    rc = SQLITE_ERROR;
  }


  return rc;
}



































/*
** Delete all cached deferred doclists. Deferred doclists are cached
** (allocated) by the sqlite3Fts3CacheDeferredDoclists() function.
*/
void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *pCsr){
  Fts3DeferredToken *pDef;
  for(pDef=pCsr->pDeferred; pDef; pDef=pDef->pNext){
    fts3PendingListDelete(pDef->pList);
    pDef->pList = 0;
  }



}

/*
** Free all entries in the pCsr->pDeffered list. Entries are added to 
** this list using sqlite3Fts3DeferToken().
*/
void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *pCsr){
  Fts3DeferredToken *pDef;
  Fts3DeferredToken *pNext;
  for(pDef=pCsr->pDeferred; pDef; pDef=pNext){
    pNext = pDef->pNext;
    fts3PendingListDelete(pDef->pList);
    sqlite3_free(pDef);
  }
  pCsr->pDeferred = 0;
}

/*
** Generate deferred-doclists for all tokens in the pCsr->pDeferred list

        rc = fts3PendingListAppendVarint(&pDef->pList, 0);
      }
    }
  }

  return rc;
}

int sqlite3Fts3DeferredTokenList(
  Fts3DeferredToken *p, 
  char **ppData, 
  int *pnData
){
  char *pRet;
  int nSkip;
  sqlite3_int64 dummy;

  *ppData = 0;
  *pnData = 0;

  if( p->pList==0 ){
    return SQLITE_OK;
  }

  pRet = (char *)sqlite3_malloc(p->pList->nData);
  if( !pRet ) return SQLITE_NOMEM;

  nSkip = sqlite3Fts3GetVarint(p->pList->aData, &dummy);
  *pnData = p->pList->nData - nSkip;
  *ppData = pRet;
  
  memcpy(pRet, &p->pList->aData[nSkip], *pnData);
  return SQLITE_OK;
}

/*
** Add an entry for token pToken to the pCsr->pDeferred list.
*/
int sqlite3Fts3DeferToken(
  Fts3Cursor *pCsr,               /* Fts3 table cursor */
  Fts3PhraseToken *pToken,        /* Token to defer */

  sqlite3_value **apVal,          /* Array of arguments */
  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
){
  Fts3Table *p = (Fts3Table *)pVtab;
  int rc = SQLITE_OK;             /* Return Code */
  int isRemove = 0;               /* True for an UPDATE or DELETE */
  sqlite3_int64 iRemove = 0;      /* Rowid removed by UPDATE or DELETE */
  u32 *aSzIns = 0;                /* Sizes of inserted documents */
  u32 *aSzDel;                    /* Sizes of deleted documents */
  int nChng = 0;                  /* Net change in number of documents */
  int bInsertDone = 0;

  assert( p->pSegments==0 );

  /* Check for a "special" INSERT operation. One of the form:
  **
  **   INSERT INTO xyz(xyz) VALUES('command');
  */
  if( nArg>1 
   && sqlite3_value_type(apVal[0])==SQLITE_NULL 
   && sqlite3_value_type(apVal[p->nColumn+2])!=SQLITE_NULL 
  ){
    rc = fts3SpecialInsert(p, apVal[p->nColumn+2]);
    goto update_out;
  }

  /* Allocate space to hold the change in document sizes */
  aSzIns = sqlite3_malloc( sizeof(aSzIns[0])*(p->nColumn+1)*2 );
  if( aSzIns==0 ){
    rc = SQLITE_NOMEM;
    goto update_out;
  }
  aSzDel = &aSzIns[p->nColumn+1];
  memset(aSzIns, 0, sizeof(aSzIns[0])*(p->nColumn+1)*2);

  /* If this is an INSERT operation, or an UPDATE that modifies the rowid
  ** value, then this operation requires constraint handling.
  **
  ** If the on-conflict mode is REPLACE, this means that the existing row

      }else{
        rc = fts3InsertData(p, apVal, pRowid);
        bInsertDone = 1;
      }
    }
  }
  if( rc!=SQLITE_OK ){
    goto update_out;

  }

  /* If this is a DELETE or UPDATE operation, remove the old record. */
  if( sqlite3_value_type(apVal[0])!=SQLITE_NULL ){
    assert( sqlite3_value_type(apVal[0])==SQLITE_INTEGER );
    rc = fts3DeleteByRowid(p, apVal[0], &nChng, aSzDel);
    isRemove = 1;

    nChng++;
  }

  if( p->bHasStat ){
    fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nChng);
  }

 update_out:
  sqlite3_free(aSzIns);
  sqlite3Fts3SegmentsClose(p);
  return rc;
}

/* 
** Flush any data in the pending-terms hash table to disk. If successful,
** merge all segments in the database (including the new segment, if 
** there was any data to flush) into a single segment. 
*/
int sqlite3Fts3Optimize(Fts3Table *p){
  int rc;
  rc = sqlite3_exec(p->db, "SAVEPOINT fts3", 0, 0, 0);
  if( rc==SQLITE_OK ){
    rc = fts3DoOptimize(p, 1);
    if( rc==SQLITE_OK || rc==SQLITE_DONE ){
      int rc2 = sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
      if( rc2!=SQLITE_OK ) rc = rc2;


    }else{
      sqlite3_exec(p->db, "ROLLBACK TO fts3", 0, 0, 0);
      sqlite3_exec(p->db, "RELEASE fts3", 0, 0, 0);
    }
  }
  sqlite3Fts3SegmentsClose(p);
  return rc;
}

#endif

  parse.h \
  sqlite3.h


# Source code to the test files.
#
TESTSRC = \
  $(TOP)/ext/fts3/fts3_test.c \
  $(TOP)/src/test1.c \
  $(TOP)/src/test2.c \
  $(TOP)/src/test3.c \
  $(TOP)/src/test4.c \
  $(TOP)/src/test5.c \
  $(TOP)/src/test6.c \
  $(TOP)/src/test7.c \

    extern int Sqlitetestrtree_Init(Tcl_Interp*);
    extern int Sqlitequota_Init(Tcl_Interp*);
    extern int Sqlitemultiplex_Init(Tcl_Interp*);
    extern int SqliteSuperlock_Init(Tcl_Interp*);
    extern int SqlitetestSyscall_Init(Tcl_Interp*);
    extern int Sqlitetestfuzzer_Init(Tcl_Interp*);
    extern int Sqlitetestwholenumber_Init(Tcl_Interp*);

#ifdef SQLITE_ENABLE_FTS3
    extern int Sqlitetestfts3_Init(Tcl_Interp *interp);
#endif

#ifdef SQLITE_ENABLE_ZIPVFS
    extern int Zipvfs_Init(Tcl_Interp*);
    Zipvfs_Init(interp);
#endif

    Sqliteconfig_Init(interp);

    Sqlitetestrtree_Init(interp);
    Sqlitequota_Init(interp);
    Sqlitemultiplex_Init(interp);
    SqliteSuperlock_Init(interp);
    SqlitetestSyscall_Init(interp);
    Sqlitetestfuzzer_Init(interp);
    Sqlitetestwholenumber_Init(interp);

#ifdef SQLITE_ENABLE_FTS3
    Sqlitetestfts3_Init(interp);
#endif

    Tcl_CreateObjCommand(interp,"load_testfixture_extensions",init_all_cmd,0,0);

#ifdef SQLITE_SSE
    Sqlitetestsse_Init(interp);
#endif
  }

# 2011 June 10
#
#    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.
#
#***********************************************************************
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# If this build does not include FTS3, skip the tests in this file.
#
ifcapable !fts3 { finish_test ; return }
source $testdir/fts3_common.tcl
source $testdir/malloc_common.tcl

set testprefix fts3auto
set sfep $sqlite_fts3_enable_parentheses
set sqlite_fts3_enable_parentheses 1

#--------------------------------------------------------------------------
# Start of Tcl infrastructure used by tests. The entry points are:
#
#   do_fts3query_test
#   fts3_make_deferrable
#   fts3_zero_long_segments 
#

#
#    do_fts3query_test TESTNAME ?OPTIONS? TABLE MATCHEXPR
#
# This proc runs several test cases on FTS3/4 table $TABLE using match
# expression $MATCHEXPR. All documents in $TABLE must be formatted so that
# they can be "tokenized" using the Tcl list commands (llength, lindex etc.).
# The name and column names used by $TABLE must not require any quoting or
# escaping when used in SQL statements.
#
# $MATCHINFO may be any expression accepted by the FTS4 MATCH operator, 
# except that the "<column-name>:token" syntax is not supported. Tcl list
# commands are used to tokenize the expression. Any parenthesis must appear
# either as separate list elements, or as the first (for opening) or last
# (for closing) character of a list element. i.e. the expression "(a OR b)c"
# will not be parsed correctly, but "( a OR b) c" will.
#
# Available OPTIONS are:
#
#     -deferred TOKENLIST
#
# If the "deferred" option is supplied, it is passed a list of tokens that
# are deferred by FTS and result in the relevant matchinfo() stats being an
# approximation. 
#
set sqlite_fts3_enable_parentheses 1
proc do_fts3query_test {tn args} {

  set nArg [llength $args]
  if {$nArg < 2 || ($nArg % 2)} {
    set cmd do_fts3query_test
    error "wrong # args: should be \"$cmd ?-deferred LIST? TABLE MATCHEXPR\""
  }
  set tbl   [lindex $args [expr $nArg-2]]
  set match [lindex $args [expr $nArg-1]]
  set deferred [list]

  foreach {k v} [lrange $args 0 [expr $nArg-3]] {
    switch -- $k {
      -deferred {
        set deferred $v
      }
      default {
        error "bad option \"$k\": must be -deferred"
      }
    }
  }

  get_near_results $tbl $match $deferred aMatchinfo

  set matchinfo_asc [list]
  foreach docid [lsort -integer -incr [array names aMatchinfo]] {
    lappend matchinfo_asc $docid $aMatchinfo($docid)
  }
  set matchinfo_desc [list]
  foreach docid [lsort -integer -decr [array names aMatchinfo]] {
    lappend matchinfo_desc $docid $aMatchinfo($docid)
  }

  set title "(\"$match\" -> [llength [array names aMatchinfo]] rows)"

  do_execsql_test $tn$title.1 "
    SELECT docid FROM $tbl WHERE $tbl MATCH '$match' ORDER BY docid ASC
  " [lsort -integer -incr [array names aMatchinfo]] 

  do_execsql_test $tn$title.2 "
    SELECT docid FROM $tbl WHERE $tbl MATCH '$match' ORDER BY docid DESC
  " [lsort -integer -decr [array names aMatchinfo]] 

  do_execsql_test $tn$title.3 "
    SELECT docid, mit(matchinfo($tbl, 'x')) FROM $tbl 
    WHERE $tbl MATCH '$match' ORDER BY docid DESC
  " $matchinfo_desc

  do_execsql_test $tn$title.4 "
    SELECT docid, mit(matchinfo($tbl, 'x')) FROM $tbl 
    WHERE $tbl MATCH '$match' ORDER BY docid ASC
  " $matchinfo_asc
}

#    fts3_make_deferrable TABLE TOKEN
#
proc fts3_make_deferrable {tbl token} {

  set stmt [sqlite3_prepare db "SELECT * FROM $tbl" -1 dummy]
  set name [sqlite3_column_name $stmt 0]
  sqlite3_finalize $stmt

  set nRow [db one "SELECT count(*) FROM $tbl"]
  set pgsz [db one "PRAGMA page_size"]
  execsql BEGIN
  for {set i 0} {$i < ($nRow * $pgsz * 1.2)/100} {incr i} {
    set doc [string repeat "$token " 100]
    execsql "INSERT INTO $tbl ($name) VALUES(\$doc)"
  }
  execsql "INSERT INTO $tbl ($name) VALUES('aaaaaaa ${token}aaaaa')"
  execsql COMMIT

  return [expr $nRow*$pgsz]
}

#    fts3_zero_long_segments TABLE ?LIMIT?
#
proc fts3_zero_long_segments {tbl limit} {
  execsql " 
    UPDATE ${tbl}_segments 
    SET block = zeroblob(length(block)) 
    WHERE length(block)>$limit
  "
  return [db changes]
}


proc mit {blob} {
  set scan(littleEndian) i*
  set scan(bigEndian) I*
  binary scan $blob $scan($::tcl_platform(byteOrder)) r
  return $r
}
db func mit mit

proc fix_near_expr {expr} { 
  set out [list]
  lappend out [lindex $expr 0]
  foreach {a b} [lrange $expr 1 end] {
    if {[string match -nocase near $a]}   { set a 10 }
    if {[string match -nocase near/* $a]} { set a [string range $a 5 end] }
    lappend out $a
    lappend out $b
  }
  return $out
}

proc get_single_near_results {tbl expr deferred arrayvar nullvar} {
  upvar $arrayvar aMatchinfo
  upvar $nullvar nullentry
  catch {array unset aMatchinfo}

  set expr [fix_near_expr $expr]

  # Calculate the expected results using [fts3_near_match]. The following
  # loop populates the "hits" and "counts" arrays as follows:
  # 
  #   1. For each document in the table that matches the NEAR expression,
  #      hits($docid) is set to 1. The set of docids that match the expression
  #      can therefore be found using [array names hits].
  #
  #   2. For each column of each document in the table, counts($docid,$iCol)
  #      is set to the -phrasecountvar output.
  #
  set res [list]
  catch { array unset hits }
  db eval "SELECT docid, * FROM $tbl" d {
    set iCol 0
    foreach col [lrange $d(*) 1 end] {
      set docid $d(docid)
      set hit [fts3_near_match $d($col) $expr -p counts($docid,$iCol)]
      if {$hit} { set hits($docid) 1 }
      incr iCol
    }
  }
  set nPhrase [expr ([llength $expr]+1)/2]
  set nCol $iCol

  # This block populates the nHit and nDoc arrays. For each phrase/column
  # in the query/table, array elements are set as follows:
  #
  #   nHit($iPhrase,$iCol) - Total number of hits for phrase $iPhrase in 
  #                          column $iCol.
  #
  #   nDoc($iPhrase,$iCol) - Number of documents with at least one hit for
  #                          phrase $iPhrase in column $iCol.
  #
  for {set iPhrase 0} {$iPhrase < $nPhrase} {incr iPhrase} {
    for {set iCol 0} {$iCol < $nCol} {incr iCol} {
      set nHit($iPhrase,$iCol) 0
      set nDoc($iPhrase,$iCol) 0
    }
  }
  foreach key [array names counts] {
    set iCol [lindex [split $key ,] 1]
    set iPhrase 0
    foreach c $counts($key) {
      if {$c>0} { incr nDoc($iPhrase,$iCol) 1 }
      incr nHit($iPhrase,$iCol) $c
      incr iPhrase
    }
  }

  if {[llength $deferred] && [llength $expr]==1} {
    set phrase [lindex $expr 0]
    set rewritten [list]
    set partial 0
    foreach tok $phrase {
      if {[lsearch $deferred $tok]>=0} {
        lappend rewritten *
      } else {
        lappend rewritten $tok
        set partial 1
      }
    }
    if {$partial==0} {
      set tblsize [db one "SELECT count(*) FROM $tbl"]
      for {set iCol 0} {$iCol < $nCol} {incr iCol} {
        set nHit(0,$iCol) $tblsize
        set nDoc(0,$iCol) $tblsize
      }
    } elseif {$rewritten != $phrase} {
      while {[lindex $rewritten end] == "*"} {
        set rewritten [lrange $rewritten 0 end-1]
      }
      while {[lindex $rewritten 0] == "*"} {
        set rewritten [lrange $rewritten 1 end]
      }
      get_single_near_results $tbl [list $rewritten] {} aRewrite nullentry
      foreach docid [array names hits] {
        set aMatchinfo($docid) $aRewrite($docid)
      }
      return
    }
  }

  # Set up the aMatchinfo array. For each document, set aMatchinfo($docid) to
  # contain the output of matchinfo('x') for the document.
  #
  foreach docid [array names hits] {
    set mi [list]
    for {set iPhrase 0} {$iPhrase<$nPhrase} {incr iPhrase} {
      for {set iCol 0} {$iCol<$nCol} {incr iCol} {
        lappend mi [lindex $counts($docid,$iCol) $iPhrase]
        lappend mi $nHit($iPhrase,$iCol)
        lappend mi $nDoc($iPhrase,$iCol)
      }
    }
    set aMatchinfo($docid) $mi
  }

  # Set up the nullentry output.
  #
  set nullentry [list]
  for {set iPhrase 0} {$iPhrase<$nPhrase} {incr iPhrase} {
    for {set iCol 0} {$iCol<$nCol} {incr iCol} {
      lappend nullentry 0 $nHit($iPhrase,$iCol) $nDoc($iPhrase,$iCol)
    }
  }
}


proc matching_brackets {expr} {
  if {[string range $expr 0 0]!="(" || [string range $expr end end] !=")"} { 
    return 0 
  }

  set iBracket 1
  set nExpr [string length $expr]
  for {set i 1} {$iBracket && $i < $nExpr} {incr i} {
    set c [string range $expr $i $i]
    if {$c == "("} {incr iBracket}
    if {$c == ")"} {incr iBracket -1}
  }

  return [expr ($iBracket==0 && $i==$nExpr)]
}

proc get_near_results {tbl expr deferred arrayvar {nullvar ""}} {
  upvar $arrayvar aMatchinfo
  if {$nullvar != ""} { upvar $nullvar nullentry }

  set expr [string trim $expr]
  while { [matching_brackets $expr] } {
    set expr [string trim [string range $expr 1 end-1]]
  }

  set prec(NOT) 1
  set prec(AND) 2
  set prec(OR)  3

  set currentprec 0
  set iBracket 0
  set expr_length [llength $expr]
  for {set i 0} {$i < $expr_length} {incr i} {
    set op [lindex $expr $i]
    if {$iBracket==0 && [info exists prec($op)] && $prec($op)>=$currentprec } {
      set opidx $i
      set currentprec $prec($op)
    } else {
      for {set j 0} {$j < [string length $op]} {incr j} {
        set c [string range $op $j $j]
        if {$c == "("} { incr iBracket +1 }
        if {$c == ")"} { incr iBracket -1 }
      }
    }
  }
  if {$iBracket!=0} { error "mismatched brackets in: $expr" }

  if {[info exists opidx]==0} {
    get_single_near_results $tbl $expr $deferred aMatchinfo nullentry
  } else {
    set eLeft  [lrange $expr 0 [expr $opidx-1]]
    set eRight [lrange $expr [expr $opidx+1] end]

    get_near_results $tbl $eLeft  $deferred aLeft  nullleft
    get_near_results $tbl $eRight $deferred aRight nullright

    switch -- [lindex $expr $opidx] {
      "NOT" {
        foreach hit [array names aLeft] {
          if {0==[info exists aRight($hit)]} {
            set aMatchinfo($hit) $aLeft($hit)
          }
        }
        set nullentry $nullleft
      }

      "AND" {
        foreach hit [array names aLeft] {
          if {[info exists aRight($hit)]} {
            set aMatchinfo($hit) [concat $aLeft($hit) $aRight($hit)]
          }
        }
        set nullentry [concat $nullleft $nullright]
      }

      "OR" {
        foreach hit [array names aLeft] {
          if {[info exists aRight($hit)]} {
            set aMatchinfo($hit) [concat $aLeft($hit) $aRight($hit)]
            unset aRight($hit)
          } else {
            set aMatchinfo($hit) [concat $aLeft($hit) $nullright]
          }
        }
        foreach hit [array names aRight] {
          set aMatchinfo($hit) [concat $nullleft $aRight($hit)]
        }

        set nullentry [concat $nullleft $nullright]
      }
    }
  }
}


# End of test procs. Actual tests are below this line.
#--------------------------------------------------------------------------

#--------------------------------------------------------------------------
# The following test cases - fts3auto-1.* - focus on testing the Tcl 
# command [fts3_near_match], which is used by other tests in this file.
#
proc test_fts3_near_match {tn doc expr res} {
  fts3_near_match $doc $expr -phrasecountvar p
  uplevel do_test [list $tn] [list [list set {} $p]] [list $res]
}

test_fts3_near_match 1.1.1 {a b c a b} a                   {2}
test_fts3_near_match 1.1.2 {a b c a b} {a 5 b 6 c}         {2 2 1}
test_fts3_near_match 1.1.3 {a b c a b} {"a b"}             {2}
test_fts3_near_match 1.1.4 {a b c a b} {"b c"}             {1}
test_fts3_near_match 1.1.5 {a b c a b} {"c c"}             {0}

test_fts3_near_match 1.2.1 "a b c d e f g" {b 2 f}         {0 0}
test_fts3_near_match 1.2.2 "a b c d e f g" {b 3 f}         {1 1}
test_fts3_near_match 1.2.3 "a b c d e f g" {f 2 b}         {0 0}
test_fts3_near_match 1.2.4 "a b c d e f g" {f 3 b}         {1 1}
test_fts3_near_match 1.2.5 "a b c d e f g" {"a b" 2 "f g"} {0 0}
test_fts3_near_match 1.2.6 "a b c d e f g" {"a b" 3 "f g"} {1 1}

set A "a b c d e f g h i j k l m n o p q r s t u v w x y z"
test_fts3_near_match 1.3.1 $A {"c d" 5 "i j" 1 "e f"}      {0 0 0}
test_fts3_near_match 1.3.2 $A {"c d" 5 "i j" 2 "e f"}      {1 1 1}

#--------------------------------------------------------------------------
# Test cases fts3auto-2.* run some simple tests using the 
# [do_fts3query_test] proc.
#
foreach {tn create} {
  1    "fts4(a, b)"
  2    "fts4(a, b, order=DESC)"
  3    "fts4(a, b, order=ASC)"
  4    "fts4(a, b, prefix=1)"
  5    "fts4(a, b, order=DESC, prefix=1)"
  6    "fts4(a, b, order=ASC, prefix=1)"
} {
  do_test 2.$tn.1 {
    catchsql { DROP TABLE t1 }
    execsql  "CREATE VIRTUAL TABLE t1 USING $create"
    for {set i 0} {$i<32} {incr i} {
      set doc [list]
      if {$i&0x01} {lappend doc one}
      if {$i&0x02} {lappend doc two}
      if {$i&0x04} {lappend doc three}
      if {$i&0x08} {lappend doc four}
      if {$i&0x10} {lappend doc five}
      execsql { INSERT INTO t1 VALUES($doc, null) }
    }
  } {}

  foreach {tn2 expr} {
    1     {one}
    2     {one NEAR/1 five}
    3     {t*}
    4     {t* NEAR/0 five}
    5     {o* NEAR/1 f*}
    6     {one NEAR five NEAR two NEAR four NEAR three}
    7     {one NEAR xyz}
    8     {one OR two}
    9     {one AND two}
    10    {one NOT two}
    11    {one AND two OR three}
    12    {three OR one AND two}
    13    {(three OR one) AND two}
    14    {(three OR one) AND two NOT (five NOT four)}
    15    {"one two"}
    16    {"one two" NOT "three four"}
  } {
    do_fts3query_test 2.$tn.2.$tn2 t1 $expr
  }
}

#--------------------------------------------------------------------------
# Some test cases involving deferred tokens.
#

foreach {tn create} {
  1    "fts4(x)"
  2    "fts4(x, order=DESC)"
} {
  catchsql { DROP TABLE t1 }
  execsql  "CREATE VIRTUAL TABLE t1 USING $create"
  do_execsql_test 3.$tn.1 {
    INSERT INTO t1(docid, x) VALUES(-2, 'a b c d e f g h i j k');
    INSERT INTO t1(docid, x) VALUES(-1, 'b c d e f g h i j k a');
    INSERT INTO t1(docid, x) VALUES(0, 'c d e f g h i j k a b');
    INSERT INTO t1(docid, x) VALUES(1, 'd e f g h i j k a b c');
    INSERT INTO t1(docid, x) VALUES(2, 'e f g h i j k a b c d');
    INSERT INTO t1(docid, x) VALUES(3, 'f g h i j k a b c d e');
    INSERT INTO t1(docid, x) VALUES(4, 'a c e g i k');
    INSERT INTO t1(docid, x) VALUES(5, 'a d g j');
    INSERT INTO t1(docid, x) VALUES(6, 'c a b');
  }

  set limit [fts3_make_deferrable t1 c]

  do_fts3query_test 3.$tn.2.1 t1 {a OR c}

  do_test 3.$tn.3 { 
    fts3_zero_long_segments t1 $limit 
  } {1}

  foreach {tn2 expr def} {
    1     {a NEAR c}            {}
    2     {a AND c}             c
    3     {"a c"}               c
    4     {"c a"}               c
    5     {"a c" NEAR/1 g}      {}
    6     {"a c" NEAR/0 g}      {}
  } {
    do_fts3query_test 3.$tn.4.$tn2 -deferred $def t1 $expr
  }
}

#--------------------------------------------------------------------------
# 
foreach {tn create} {
  1    "fts4(x, y)"
  2    "fts4(x, y, order=DESC)"
  3    "fts4(x, y, order=DESC, prefix=2)"
} {

  execsql [subst {
    DROP TABLE t1;
    CREATE VIRTUAL TABLE t1 USING $create;
    INSERT INTO t1 VALUES('one two five four five', '');
    INSERT INTO t1 VALUES('', 'one two five four five');
    INSERT INTO t1 VALUES('one two', 'five four five');
  }]

  do_fts3query_test 4.$tn.1.1 t1 {one AND five}
  do_fts3query_test 4.$tn.1.2 t1 {one NEAR five}
  do_fts3query_test 4.$tn.1.3 t1 {one NEAR/1 five}
  do_fts3query_test 4.$tn.1.4 t1 {one NEAR/2 five}
  do_fts3query_test 4.$tn.1.5 t1 {one NEAR/3 five}

  do_test 4.$tn.2 { 
    set limit [fts3_make_deferrable t1 five]
    execsql { INSERT INTO t1(t1) VALUES('optimize') }
    expr {[fts3_zero_long_segments t1 $limit]>0}
  } {1}

  do_fts3query_test 4.$tn.3.1 -deferred five t1 {one AND five}
  do_fts3query_test 4.$tn.3.2 -deferred five t1 {one NEAR five}
  do_fts3query_test 4.$tn.3.3 -deferred five t1 {one NEAR/1 five}
  do_fts3query_test 4.$tn.3.4 -deferred five t1 {one NEAR/2 five}
  do_fts3query_test 4.$tn.3.5 -deferred five t1 {one NEAR/3 five}

  do_fts3query_test 4.$tn.4.1 -deferred fi* t1 {on* AND fi*}
  do_fts3query_test 4.$tn.4.2 -deferred fi* t1 {on* NEAR fi*}
  do_fts3query_test 4.$tn.4.3 -deferred fi* t1 {on* NEAR/1 fi*}
  do_fts3query_test 4.$tn.4.4 -deferred fi* t1 {on* NEAR/2 fi*}
  do_fts3query_test 4.$tn.4.5 -deferred fi* t1 {on* NEAR/3 fi*}
}

set sqlite_fts3_enable_parentheses $sfep
finish_test