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Overview
Comment:Changes to improve performance and support LIMIT clauses on fts3 tables. This branch is unstable for now.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | fts3-prefix-search
Files: files | file ages | folders
SHA1:28149a7882a1e9dfe4a75ec5b91d176ebe6284e9
User & Date: dan 2011-06-02 19:57:24
Context
2011-06-03
18:00
FTS changes: Remove unreachable code. Fix bugs. When processing a large doclist incrementally, read from disk incrementally too. check-in: a4c7e282 user: dan tags: fts3-prefix-search
2011-06-02
19:57
Changes to improve performance and support LIMIT clauses on fts3 tables. This branch is unstable for now. check-in: 28149a78 user: dan tags: fts3-prefix-search
2011-05-28
15:57
Minor changes made while planning a larger change. check-in: 84097a4c user: dan tags: fts3-prefix-search
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3989

#include "fts3.h"
#ifndef SQLITE_CORE 
# include "sqlite3ext.h"
  SQLITE_EXTENSION_INIT1
#endif




/* 
** Write a 64-bit variable-length integer to memory starting at p[0].
** The length of data written will be between 1 and FTS3_VARINT_MAX bytes.
** The number of bytes written is returned.
*/
int sqlite3Fts3PutVarint(char *p, sqlite_int64 v){
  unsigned char *q = (unsigned char *) p;
................................................................................
  } 

  /* Regardless of the strategy selected, FTS can deliver rows in rowid (or
  ** docid) order. Both ascending and descending are possible. 
  */
  if( pInfo->nOrderBy==1 ){
    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;
  }


  return SQLITE_OK;
}

/*
** Implementation of xOpen method.
*/
................................................................................
  sqlite3Fts3FreeDeferredTokens(pCsr);
  sqlite3_free(pCsr->aDoclist);
  sqlite3_free(pCsr->aMatchinfo);
  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 ){
    pCsr->isRequireSeek = 0;
    sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);

    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.
................................................................................
  return SQLITE_OK;
}

/*
** Append SegReader object pNew to the end of the pCsr->apSegment[] array.
*/
static int fts3SegReaderCursorAppend(
  Fts3SegReaderCursor *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 ){
................................................................................
  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 */
  Fts3SegReaderCursor *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
................................................................................
  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 */
  Fts3SegReaderCursor *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(Fts3SegReaderCursor));

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

static int fts3SegReaderCursorAddZero(
  Fts3Table *p,
  const char *zTerm,
  int nTerm,
  Fts3SegReaderCursor *pCsr
){
  return fts3SegReaderCursor(p, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0,pCsr);
}


static int fts3TermSegReaderCursor(
  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 */
  Fts3SegReaderCursor **ppSegcsr  /* OUT: Allocated seg-reader cursor */
){
  Fts3SegReaderCursor *pSegcsr;   /* Object to allocate and return */
  int rc = SQLITE_NOMEM;          /* Return code */

  pSegcsr = sqlite3_malloc(sizeof(Fts3SegReaderCursor));
  if( pSegcsr ){
    int i;
    int nCost = 0;
    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);

        }
      }

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

    if( bFound==0 ){
      rc = sqlite3Fts3SegReaderCursor(
          p, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, isPrefix, 0, pSegcsr
      );

    }
    for(i=0; rc==SQLITE_OK && i<pSegcsr->nSegment; i++){
      rc = sqlite3Fts3SegReaderCost(pCsr, pSegcsr->apSegment[i], &nCost);
    }
    pSegcsr->nCost = nCost;
  }

  *ppSegcsr = pSegcsr;
  return rc;
}

static void fts3SegReaderCursorFree(Fts3SegReaderCursor *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 */
  Fts3SegReaderCursor *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;

................................................................................
  int isTermPos = (pPhrase->nToken>1 || isReqPos);
  Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
  int isFirst = 1;

  int iPrevTok = 0;
  int nDoc = 0;

  /* If this is an xFilter() evaluation, create a segment-reader for each
  ** phrase token. Or, if this is an xNext() or snippet/offsets/matchinfo
  ** evaluation, only create segment-readers if there are no Fts3DeferredToken
  ** objects attached to the phrase-tokens.
  */
  for(ii=0; ii<pPhrase->nToken; ii++){
    Fts3PhraseToken *pTok = &pPhrase->aToken[ii];
    if( pTok->pSegcsr==0 ){
      if( (pCsr->eEvalmode==FTS3_EVAL_FILTER)
       || (pCsr->eEvalmode==FTS3_EVAL_NEXT && pCsr->pDeferred==0) 
       || (pCsr->eEvalmode==FTS3_EVAL_MATCHINFO && pTok->bFulltext) 
      ){
        rc = fts3TermSegReaderCursor(
            pCsr, pTok->z, pTok->n, pTok->isPrefix, &pTok->pSegcsr
        );
        if( rc!=SQLITE_OK ) return rc;
      }
    }
  }

  for(ii=0; ii<pPhrase->nToken; ii++){
    Fts3PhraseToken *pTok;        /* Token to find doclist for */
    int iTok = 0;                 /* The token being queried this iteration */
    char *pList = 0;              /* Pointer to token doclist */
    int nList = 0;                /* Size of buffer at pList */

    /* Select a token to process. If this is an xFilter() call, then tokens 
................................................................................
      pTok = &pPhrase->aToken[iTok];
    }else{
      int nMinCost = 0x7FFFFFFF;
      int jj;

      /* Find the remaining token with the lowest cost. */
      for(jj=0; jj<pPhrase->nToken; jj++){
        Fts3SegReaderCursor *pSegcsr = pPhrase->aToken[jj].pSegcsr;
        if( pSegcsr && pSegcsr->nCost<nMinCost ){
          iTok = jj;
          nMinCost = pSegcsr->nCost;
        }
      }
      pTok = &pPhrase->aToken[iTok];

................................................................................
  assert( pCsr->eEvalmode==FTS3_EVAL_FILTER );
  if( pnExpr && pExpr->eType!=FTSQUERY_AND ){
    (*pnExpr)++;
    pnExpr = 0;
  }

  if( pExpr->eType==FTSQUERY_PHRASE ){

    Fts3Phrase *pPhrase = pExpr->pPhrase;
    int ii;

    for(ii=0; rc==SQLITE_OK && ii<pPhrase->nToken; ii++){
      Fts3PhraseToken *pTok = &pPhrase->aToken[ii];
      if( pTok->pSegcsr==0 ){
        rc = fts3TermSegReaderCursor(
            pCsr, pTok->z, pTok->n, pTok->isPrefix, &pTok->pSegcsr
        );
      }
    }
  }else{ 
    rc = fts3ExprAllocateSegReaders(pCsr, pExpr->pLeft, pnExpr);
    if( rc==SQLITE_OK ){
................................................................................
static int fts3ExprCost(Fts3Expr *pExpr){
  int nCost;                      /* Return value */
  if( pExpr->eType==FTSQUERY_PHRASE ){
    Fts3Phrase *pPhrase = pExpr->pPhrase;
    int ii;
    nCost = 0;
    for(ii=0; ii<pPhrase->nToken; ii++){
      Fts3SegReaderCursor *pSegcsr = pPhrase->aToken[ii].pSegcsr;
      if( pSegcsr ) nCost += pSegcsr->nCost;
    }
  }else{
    nCost = fts3ExprCost(pExpr->pLeft) + fts3ExprCost(pExpr->pRight);
  }
  return nCost;
}
................................................................................
** subsequently to determine whether or not an EOF was hit.
*/
static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){
  int res;
  int rc = SQLITE_OK;             /* Return code */
  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;




  pCsr->eEvalmode = FTS3_EVAL_NEXT;
  do {
    if( pCsr->aDoclist==0 ){
      if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){
        pCsr->isEof = 1;
        rc = sqlite3_reset(pCsr->pStmt);
        break;
................................................................................
        }
      }
      sqlite3_reset(pCsr->pStmt);
      pCsr->isRequireSeek = 1;
      pCsr->isMatchinfoNeeded = 1;
    }
  }while( SQLITE_OK==(rc = fts3EvalDeferred(pCsr, &res)) && res==0 );


  return rc;
}

/*
** This is the xFilter interface for the virtual table.  See
** the virtual table xFilter method documentation for additional
................................................................................
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 */
){
  const char *azSql[] = {
    "SELECT %s FROM %Q.'%q_content' AS x WHERE docid = ?",   /* non-full-scan */
    "SELECT %s FROM %Q.'%q_content' AS x ORDER BY docid %s", /* full-scan */
  };
  int rc;                         /* Return code */
  char *zSql;                     /* SQL statement used to access %_content */
  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;

  UNUSED_PARAMETER(idxStr);
  UNUSED_PARAMETER(nVal);

................................................................................
    }

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

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

    rc = fts3EvalExpr(pCsr, pCsr->pExpr, &pCsr->aDoclist, &pCsr->nDoclist, 0);


    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.
  */
  zSql = (char *)azSql[idxNum==FTS3_FULLSCAN_SEARCH];
  zSql = sqlite3_mprintf(

      zSql, p->zReadExprlist, p->zDb, p->zName, (idxStr ? idxStr : "ASC")
  );
  if( !zSql ){
    rc = SQLITE_NOMEM;
  }else{




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

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

  }
  pCsr->eSearch = (i16)idxNum;

  assert( pCsr->desc==0 );
  if( rc!=SQLITE_OK ) return rc;

  if( rc==SQLITE_OK && pCsr->nDoclist>0 && idxStr && idxStr[0]=='D' ){
    sqlite3_int64 iDocid = 0;
    char *csr = pCsr->aDoclist;
    while( csr<&pCsr->aDoclist[pCsr->nDoclist] ){
      fts3GetDeltaVarint(&csr, &iDocid);
    }
    pCsr->pNextId = csr;
................................................................................
** 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;


  if( pCsr->aDoclist ){
    *pRowid = pCsr->iPrevId;
  }else{
    /* This branch runs if the query is implemented using a full-table scan
    ** (not using the full-text index). In this case grab the rowid from the
    ** SELECT statement.
    */
    assert( pCsr->isRequireSeek==0 );
................................................................................
/*
** Load the doclist associated with expression pExpr to pExpr->aDoclist.
** The loaded doclist contains positions as well as the document ids.
** This is used by the matchinfo(), snippet() and offsets() auxillary
** functions.
*/
int sqlite3Fts3ExprLoadDoclist(Fts3Cursor *pCsr, Fts3Expr *pExpr){
  int rc;

  Fts3Phrase *pPhrase = pExpr->pPhrase;
  assert( pExpr->eType==FTSQUERY_PHRASE && pPhrase );
  assert( pCsr->eEvalmode==FTS3_EVAL_NEXT );
  rc = fts3EvalExpr(pCsr, pExpr, &pPhrase->aDoclist, &pPhrase->nDoclist, 1);

  return rc;
}

/*
** TODO: This is something to do with matchinfo(). Similar to
** sqlite3ExprLoadDoclists() but slightly different.
**
................................................................................
*/
int sqlite3Fts3ExprLoadFtDoclist(
  Fts3Cursor *pCsr, 
  Fts3Expr *pExpr,
  char **paDoclist,
  int *pnDoclist
){
  int rc;
  assert( pCsr->eEvalmode==FTS3_EVAL_NEXT );
  assert( pExpr->eType==FTSQUERY_PHRASE && pExpr->pPhrase );


  pCsr->eEvalmode = FTS3_EVAL_MATCHINFO;
  rc = fts3EvalExpr(pCsr, pExpr, paDoclist, pnDoclist, 1);
  pCsr->eEvalmode = FTS3_EVAL_NEXT;
  return rc;
}


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


/*
** After ExprLoadDoclist() (see above) has been called, this function is
** used to iterate/search through the position lists that make up the doclist
** stored in pExpr->aDoclist.
*/
char *sqlite3Fts3FindPositions(
  Fts3Cursor *pCursor,            /* Associate FTS3 cursor */
  Fts3Expr *pExpr,                /* Access this expressions doclist */
  sqlite3_int64 iDocid,           /* Docid associated with requested pos-list */
  int iCol                        /* Column of requested pos-list */
){
  Fts3Phrase *pPhrase = pExpr->pPhrase;
  assert( pPhrase->isLoaded );

  if( pPhrase->aDoclist ){
    char *pEnd = &pPhrase->aDoclist[pPhrase->nDoclist];
    char *pCsr;

    if( pPhrase->pCurrent==0 ){
      if( pCursor->desc==0 ){
        pPhrase->pCurrent = pPhrase->aDoclist;
        pPhrase->iCurrent = 0;
        fts3GetDeltaVarint(&pPhrase->pCurrent, &pPhrase->iCurrent);
      }else{
        pCsr = pPhrase->aDoclist;
        while( pCsr<pEnd ){
          fts3GetDeltaVarint(&pCsr, &pPhrase->iCurrent);
          fts3PoslistCopy(0, &pCsr);
        }
        fts3ReversePoslist(pPhrase->aDoclist, &pCsr);
        pPhrase->pCurrent = pCsr;
      }
    }
    pCsr = pPhrase->pCurrent;
    assert( pCsr );

    while( (pCursor->desc==0 && pCsr<pEnd) 
        || (pCursor->desc && pCsr>pPhrase->aDoclist) 
    ){
      if( pCursor->desc==0 && pPhrase->iCurrent<iDocid ){
        fts3PoslistCopy(0, &pCsr);
        if( pCsr<pEnd ){
          fts3GetDeltaVarint(&pCsr, &pPhrase->iCurrent);
        }
        pPhrase->pCurrent = pCsr;
      }else if( pCursor->desc && pPhrase->iCurrent>iDocid ){
        fts3GetReverseDeltaVarint(&pCsr, pPhrase->aDoclist, &pPhrase->iCurrent);
        fts3ReversePoslist(pPhrase->aDoclist, &pCsr);
        pPhrase->pCurrent = pCsr;
      }else{
        if( pPhrase->iCurrent==iDocid ){
          int iThis = 0;
          if( iCol<0 ){
            /* If iCol is negative, return a pointer to the start of the
            ** position-list (instead of a pointer to the start of a list
            ** of offsets associated with a specific column).
            */
            return pCsr;
          }
          while( iThis<iCol ){
            fts3ColumnlistCopy(0, &pCsr);
            if( *pCsr==0x00 ) return 0;
            pCsr++;
            pCsr += sqlite3Fts3GetVarint32(pCsr, &iThis);
          }
          if( iCol==iThis && (*pCsr&0xFE) ) return pCsr;
        }
        return 0;
      }
    }
  }

  return 0;
}

/*
** 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
................................................................................
  char **pzErrMsg,
  const sqlite3_api_routines *pApi
){
  SQLITE_EXTENSION_INIT2(pApi)
  return sqlite3Fts3Init(db);
}
#endif






































































































































































































































































































































































































































































































































































































































































































































































































































































































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309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
....
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220

1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
....
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272

1273
1274
1275
1276
1277
1278
1279
1280
1281
....
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
....
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
....
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
....
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
....
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
....
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
....
2587
2588
2589
2590
2591
2592
2593




















2594
2595
2596
2597
2598
2599
2600
....
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
....
2813
2814
2815
2816
2817
2818
2819
2820
2821

2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
....
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
....
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
....
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
....
3219
3220
3221
3222
3223
3224
3225
3226




3227
3228
3229
3230
3231
3232
3233
....
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284



3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297

3298
3299

3300
3301
3302
3303
3304
3305
3306
3307
....
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
....
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
....
3474
3475
3476
3477
3478
3479
3480
3481

3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
....
3502
3503
3504
3505
3506
3507
3508












































































3509
3510
3511
3512
3513
3514
3515
....
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
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#include "fts3.h"
#ifndef SQLITE_CORE 
# include "sqlite3ext.h"
  SQLITE_EXTENSION_INIT1
#endif

static char *fts3EvalPhrasePoslist(Fts3Phrase *, int *);
static sqlite3_int64 fts3EvalPhraseDocid(Fts3Phrase *);

/* 
** Write a 64-bit variable-length integer to memory starting at p[0].
** The length of data written will be between 1 and FTS3_VARINT_MAX bytes.
** The number of bytes written is returned.
*/
int sqlite3Fts3PutVarint(char *p, sqlite_int64 v){
  unsigned char *q = (unsigned char *) p;
................................................................................
  } 

  /* Regardless of the strategy selected, FTS can deliver rows in rowid (or
  ** docid) order. Both ascending and descending are possible. 
  */
  if( pInfo->nOrderBy==1 ){
    struct sqlite3_index_orderby *pOrder = &pInfo->aOrderBy[0];
    if( pOrder->desc==0 
     && (pOrder->iColumn<0 || pOrder->iColumn==p->nColumn+1) 
    ){
      if( pOrder->desc ){
        pInfo->idxStr = "DESC";
      }else{
        pInfo->idxStr = "ASC";
      }

      pInfo->orderByConsumed = 1;
    }
  }

  return SQLITE_OK;
}

/*
** Implementation of xOpen method.
*/
................................................................................
  sqlite3Fts3FreeDeferredTokens(pCsr);
  sqlite3_free(pCsr->aDoclist);
  sqlite3_free(pCsr->aMatchinfo);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

static int fts3RowidMethod(sqlite3_vtab_cursor *, sqlite3_int64*);

/*
** 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.
................................................................................
  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 ){
................................................................................
  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
................................................................................
  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 nCost = 0;
    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(
................................................................................
      }
    }

    if( bFound==0 ){
      rc = sqlite3Fts3SegReaderCursor(
          p, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, isPrefix, 0, pSegcsr
      );
      pSegcsr->bLookup = !isPrefix;
    }
    for(i=0; rc==SQLITE_OK && i<pSegcsr->nSegment; i++){
      rc = sqlite3Fts3SegReaderCost(pCsr, pSegcsr->apSegment[i], &nCost);
    }
    pSegcsr->nCost = nCost;
  }

  *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;

................................................................................
  int isTermPos = (pPhrase->nToken>1 || isReqPos);
  Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
  int isFirst = 1;

  int iPrevTok = 0;
  int nDoc = 0;





















  for(ii=0; ii<pPhrase->nToken; ii++){
    Fts3PhraseToken *pTok;        /* Token to find doclist for */
    int iTok = 0;                 /* The token being queried this iteration */
    char *pList = 0;              /* Pointer to token doclist */
    int nList = 0;                /* Size of buffer at pList */

    /* Select a token to process. If this is an xFilter() call, then tokens 
................................................................................
      pTok = &pPhrase->aToken[iTok];
    }else{
      int nMinCost = 0x7FFFFFFF;
      int jj;

      /* Find the remaining token with the lowest cost. */
      for(jj=0; jj<pPhrase->nToken; jj++){
        Fts3MultiSegReader *pSegcsr = pPhrase->aToken[jj].pSegcsr;
        if( pSegcsr && pSegcsr->nCost<nMinCost ){
          iTok = jj;
          nMinCost = pSegcsr->nCost;
        }
      }
      pTok = &pPhrase->aToken[iTok];

................................................................................
  assert( pCsr->eEvalmode==FTS3_EVAL_FILTER );
  if( pnExpr && pExpr->eType!=FTSQUERY_AND ){
    (*pnExpr)++;
    pnExpr = 0;
  }

  if( pExpr->eType==FTSQUERY_PHRASE ){
    int ii;                       /* Used to iterate through phrase tokens */
    Fts3Phrase *pPhrase = pExpr->pPhrase;


    for(ii=0; rc==SQLITE_OK && ii<pPhrase->nToken; ii++){
      Fts3PhraseToken *pTok = &pPhrase->aToken[ii];
      if( pTok->pSegcsr==0 ){
        rc = sqlite3Fts3TermSegReaderCursor(
            pCsr, pTok->z, pTok->n, pTok->isPrefix, &pTok->pSegcsr
        );
      }
    }
  }else{ 
    rc = fts3ExprAllocateSegReaders(pCsr, pExpr->pLeft, pnExpr);
    if( rc==SQLITE_OK ){
................................................................................
static int fts3ExprCost(Fts3Expr *pExpr){
  int nCost;                      /* Return value */
  if( pExpr->eType==FTSQUERY_PHRASE ){
    Fts3Phrase *pPhrase = pExpr->pPhrase;
    int ii;
    nCost = 0;
    for(ii=0; ii<pPhrase->nToken; ii++){
      Fts3MultiSegReader *pSegcsr = pPhrase->aToken[ii].pSegcsr;
      if( pSegcsr ) nCost += pSegcsr->nCost;
    }
  }else{
    nCost = fts3ExprCost(pExpr->pLeft) + fts3ExprCost(pExpr->pRight);
  }
  return nCost;
}
................................................................................
** subsequently to determine whether or not an EOF was hit.
*/
static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){
  int res;
  int rc = SQLITE_OK;             /* Return code */
  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;

  if( pCsr->bIncremental ){
    rc = sqlite3Fts3EvalNext(pCsr, pCsr->pExpr);
  }else{
    pCsr->eEvalmode = FTS3_EVAL_NEXT;
    do {
      if( pCsr->aDoclist==0 ){
        if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){
          pCsr->isEof = 1;
          rc = sqlite3_reset(pCsr->pStmt);
          break;
................................................................................
          }
        }
        sqlite3_reset(pCsr->pStmt);
        pCsr->isRequireSeek = 1;
        pCsr->isMatchinfoNeeded = 1;
      }
    }while( SQLITE_OK==(rc = fts3EvalDeferred(pCsr, &res)) && res==0 );
  }

  return rc;
}

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

................................................................................
    }

    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;

    pCsr->bIncremental = 1;
    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 = (idxStr ? idxStr : "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;
  }


  assert( pCsr->desc==0 );

  pCsr->eSearch = (i16)idxNum;
  if( rc==SQLITE_OK && pCsr->nDoclist>0 && idxStr && idxStr[0]=='D' ){
    sqlite3_int64 iDocid = 0;
    char *csr = pCsr->aDoclist;
    while( csr<&pCsr->aDoclist[pCsr->nDoclist] ){
      fts3GetDeltaVarint(&csr, &iDocid);
    }
    pCsr->pNextId = csr;
................................................................................
** 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;
  if( pCsr->bIncremental ){
    *pRowid = sqlite3Fts3EvalDocid(pCsr, pCsr->pExpr);
  }else if( pCsr->aDoclist ){
    *pRowid = pCsr->iPrevId;
  }else{
    /* This branch runs if the query is implemented using a full-table scan
    ** (not using the full-text index). In this case grab the rowid from the
    ** SELECT statement.
    */
    assert( pCsr->isRequireSeek==0 );
................................................................................
/*
** Load the doclist associated with expression pExpr to pExpr->aDoclist.
** The loaded doclist contains positions as well as the document ids.
** This is used by the matchinfo(), snippet() and offsets() auxillary
** functions.
*/
int sqlite3Fts3ExprLoadDoclist(Fts3Cursor *pCsr, Fts3Expr *pExpr){
  int rc = SQLITE_OK;
  if( pCsr->bIncremental==0 ){
    Fts3Phrase *pPhrase = pExpr->pPhrase;
    assert( pExpr->eType==FTSQUERY_PHRASE && pPhrase );
    assert( pCsr->eEvalmode==FTS3_EVAL_NEXT );
    rc = fts3EvalExpr(pCsr, pExpr, &pPhrase->aDoclist, &pPhrase->nDoclist, 1);
  }
  return rc;
}

/*
** TODO: This is something to do with matchinfo(). Similar to
** sqlite3ExprLoadDoclists() but slightly different.
**
................................................................................
*/
int sqlite3Fts3ExprLoadFtDoclist(
  Fts3Cursor *pCsr, 
  Fts3Expr *pExpr,
  char **paDoclist,
  int *pnDoclist
){
  int rc = SQLITE_OK;

  assert( pExpr->eType==FTSQUERY_PHRASE && pExpr->pPhrase );
  assert( pCsr->eEvalmode==FTS3_EVAL_NEXT );
  assert( pCsr->bIncremental==0 );
  pCsr->eEvalmode = FTS3_EVAL_MATCHINFO;
  rc = fts3EvalExpr(pCsr, pExpr, paDoclist, pnDoclist, 1);
  pCsr->eEvalmode = FTS3_EVAL_NEXT;
  return rc;
}


................................................................................
    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
................................................................................
  char **pzErrMsg,
  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 *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{
      fts3EvalAllocateReaders(pCsr, pExpr->pLeft, pnToken, pRc);
      fts3EvalAllocateReaders(pCsr, pExpr->pRight, pnToken, 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 );
          fts3DoclistMerge(MERGE_POS_PHRASE, iToken-iPrev, 
              0, pThis, &nThis, aDoclist, nDoclist, pThis, nThis, 0
          );
          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){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int iToken;
  int rc = SQLITE_OK;

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

  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;
    }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.nList = (aOut - pPhrase->doclist.pList);
        sqlite3_free(aPoslist);
      }else{
        sqlite3_free(aOut);
        pPhrase->doclist.pList = 0;
        pPhrase->doclist.nList = 0;
      }
    }
  }

  return SQLITE_OK;
}


/*
** The following three functions:
**
**     fts3EvalPhraseStart()
**     fts3EvalPhraseNext()
**     fts3EvalPhraseReset()
**
** May be used with a phrase object after fts3EvalAllocateReaders() has been
** called to iterate through the set of docids that match the phrase.
**
** After a successful call to fts3EvalPhraseNext(), the following two 
** functions may be called to access the current docid and position-list.
**
**     fts3EvalPhraseDocid()
**     fts3EvalPhrasePoslist()
*/
static int fts3EvalPhraseStart(Fts3Cursor *pCsr, int bOptOk, Fts3Phrase *p){
  int rc;
  Fts3Doclist *pList = &p->doclist;
  Fts3PhraseToken *pFirst = &p->aToken[0];

  assert( pList->aAll==0 );

  if( p->nToken==1 && bOptOk==1 
   && pFirst->pSegcsr && pFirst->pSegcsr->bLookup 
  ){
    /* Use the incremental approach. */
    Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
    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;
}

/*
** 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;

  if( p->bIncr ){
    Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
    assert( p->nToken==1 );
    rc = sqlite3Fts3MsrIncrNext(pTab, p->aToken[0].pSegcsr, 
        &p->doclist.iDocid, &p->doclist.pList, &p->doclist.nList
    );
    if( rc==SQLITE_OK && !p->doclist.pList ){
      *pbEof = 1;
    }
  }else{
    char *pIter;
    Fts3Doclist *pDL = &p->doclist;

    if( pDL->pNextDocid ){
      pIter = pDL->pNextDocid;
    }else{
      pIter = pDL->aAll;
    }

    if( pIter>=&pDL->aAll[pDL->nAll] ){
      /* We have already reached the end of this doclist. EOF. */
      *pbEof = 1;
    }else{
      fts3GetDeltaVarint(&pIter, &pDL->iDocid);
      pDL->pList = pIter;
      fts3PoslistCopy(0, &pIter);
      pDL->nList = (pIter - pDL->pList);
      pDL->pNextDocid = pIter;
      *pbEof = 0;
    }
  }

  return rc;
}

static int fts3EvalPhraseReset(Fts3Cursor *pCsr, Fts3Phrase *p){
  return SQLITE_OK;
}

static sqlite3_int64 fts3EvalPhraseDocid(Fts3Phrase *p){
  return p->doclist.iDocid;
}

static char *fts3EvalPhrasePoslist(Fts3Phrase *p, int *pnList){
  if( pnList ){
    *pnList = p->doclist.nList;
  }
  return p->doclist.pList;
}

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{
      if( pExpr->eType==FTSQUERY_NEAR ){
        bOptOk = 0;
      }
      fts3EvalStartReaders(pCsr, pExpr->pLeft, bOptOk, pRc);
      fts3EvalStartReaders(pCsr, pExpr->pRight, bOptOk, pRc);
      pExpr->bDeferred = (pExpr->pLeft->bDeferred && pExpr->pRight->bDeferred);
    }
  }
}

static void fts3EvalNearMerge(
  Fts3Expr *p1,
  Fts3Expr *p2,
  int nNear,
  int *pRc
){
  if( *pRc==SQLITE_OK ){
    int rc;                         /* Return code */
    Fts3Phrase *pLeft = p1->pPhrase;
    Fts3Phrase *pRight = p2->pPhrase;
  
    assert( p2->eType==FTSQUERY_PHRASE && pLeft );
    assert( p2->eType==FTSQUERY_PHRASE && pRight );
  
    if( pLeft->doclist.aAll==0 ){
      sqlite3_free(pRight->doclist.aAll);
      pRight->doclist.aAll = 0;
      pRight->doclist.nAll = 0;
    }else if( pRight->doclist.aAll ){
      char *aOut;                 /* Buffer in which to assemble new doclist */
      int nOut;                   /* Size of buffer aOut in bytes */
  
      *pRc = fts3NearMerge(MERGE_POS_NEAR, nNear, 
          pLeft->nToken, pLeft->doclist.aAll, pLeft->doclist.nAll,
          pRight->nToken, pRight->doclist.aAll, pRight->doclist.nAll,
          &aOut, &nOut
      );
      sqlite3_free(pRight->doclist.aAll);
      pRight->doclist.aAll = aOut;
      pRight->doclist.nAll = nOut;
    }
  }
}

static void fts3EvalNearTrim(Fts3Cursor *pCsr, Fts3Expr *pExpr, int *pRc){

  if( pExpr && SQLITE_OK==*pRc ){
    if( pExpr->eType==FTSQUERY_NEAR ){
      Fts3Expr *pLeft = pExpr->pLeft;
      int nPhrase = 2;
      Fts3Expr **aPhrase;

      assert( pLeft );
      assert( pExpr->pRight );
      assert( pExpr->pRight->eType==FTSQUERY_PHRASE );

      while( pLeft->eType!=FTSQUERY_PHRASE ){
        assert( pLeft->eType==FTSQUERY_NEAR );
        assert( pLeft->pRight->eType==FTSQUERY_PHRASE );
        pLeft = pLeft->pLeft;
        nPhrase++;
      }

      aPhrase = (Fts3Expr **)sqlite3_malloc(sizeof(Fts3Expr *) * nPhrase);
      if( !aPhrase ){
        *pRc = SQLITE_NOMEM;
      }else{
        int i = 1;
        aPhrase[0] = pLeft;
        do {
          pLeft = pLeft->pParent;
          aPhrase[i++] = pLeft->pRight;
        }while( pLeft!=pExpr );

        for(i=0; i<(nPhrase-1); i++){
          int nNear = aPhrase[i+1]->pParent->nNear;
          fts3EvalNearMerge(aPhrase[i], aPhrase[i+1], nNear, pRc);
        }
        for(i=nPhrase-2; i>=0; i--){
          int nNear = aPhrase[i+1]->pParent->nNear;
          fts3EvalNearMerge(aPhrase[i+1], aPhrase[i], nNear, pRc);
        }

        sqlite3_free(aPhrase);
      }

    }else{
      fts3EvalNearTrim(pCsr, pExpr->pLeft, pRc);
      fts3EvalNearTrim(pCsr, pExpr->pRight, pRc);
    }
  }
}

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

static void fts3EvalTokenCosts(
  Fts3Cursor *pCsr, 
  Fts3Expr *pExpr, 
  Fts3TokenAndCost **ppTC,
  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->pToken = &pPhrase->aToken[i];
        pTC->iCol = pPhrase->iColumn;
        *pRc = sqlite3Fts3MsrOvfl(pCsr, pTC->pToken->pSegcsr, &pTC->nOvfl);
      }
    }else if( pExpr->eType==FTSQUERY_AND ){
      fts3EvalTokenCosts(pCsr, pExpr->pLeft, ppTC, pRc);
      fts3EvalTokenCosts(pCsr, pExpr->pRight, ppTC, 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->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;
}

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

  /* Allocate a MultiSegReader for each token in the expression. */
  fts3EvalAllocateReaders(pCsr, pExpr, &nToken, &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 can be 
  ** deferred (strategy 3). */
  if( rc==SQLITE_OK && bOptOk && nToken>1 && pTab->bHasStat ){
    Fts3TokenAndCost *aTC;
    aTC = (Fts3TokenAndCost *)sqlite3_malloc(sizeof(Fts3TokenAndCost) * nToken);
    if( !aTC ){
      rc = SQLITE_NOMEM;
    }else{
      int ii;
      int nDocEst = 0;
      int nDocSize;
      Fts3TokenAndCost *pTC = aTC;

      rc = fts3EvalAverageDocsize(pCsr, &nDocSize);
      fts3EvalTokenCosts(pCsr, pExpr, &pTC, &rc);
      nToken = pTC-aTC;

      for(ii=0; rc==SQLITE_OK && ii<nToken; ii++){
        int jj;
        pTC = 0;
        for(jj=0; jj<nToken; jj++){
          if( aTC[jj].pToken && (!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;
      }
      sqlite3_free(aTC);
    }
  }

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

  /* Fix the results of NEAR expressions. */
  fts3EvalNearTrim(pCsr, pExpr, &rc);

  return rc;
}

static void fts3EvalNext(
  Fts3Cursor *pCsr, 
  Fts3Expr *pExpr, 
  int *pRc
){
  if( *pRc==SQLITE_OK ){

    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 ){
            int iDiff = 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;

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

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

      default:
        assert( pExpr->eType==FTSQUERY_PHRASE );
        *pRc = fts3EvalPhraseNext(pCsr, pExpr->pPhrase, &pExpr->bEof);
        pExpr->iDocid = fts3EvalPhraseDocid(pExpr->pPhrase);
        break;
    }
  }
}

static int fts3EvalDeferredTest(Fts3Cursor *pCsr, Fts3Expr *pExpr, int *pRc){
  int bHit = 0;
  if( *pRc==SQLITE_OK ){
    switch( pExpr->eType ){
      case FTSQUERY_NEAR:
      case FTSQUERY_AND:
        bHit = (
            fts3EvalDeferredTest(pCsr, pExpr->pLeft, pRc)
         && fts3EvalDeferredTest(pCsr, pExpr->pRight, pRc)
        );
        break;

      case FTSQUERY_OR:
        bHit = (
            fts3EvalDeferredTest(pCsr, pExpr->pLeft, pRc)
         || fts3EvalDeferredTest(pCsr, pExpr->pRight, pRc)
        );
        break;

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

      default:
        assert( pExpr->eType==FTSQUERY_PHRASE );
        *pRc = fts3EvalDeferredPhrase(pCsr, pExpr->pPhrase);
        bHit = (pExpr->pPhrase->doclist.pList!=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.
*/
static int fts3EvalLoadDeferred(Fts3Cursor *pCsr, int *pRc){
  int rc = *pRc;
  int bMiss = 0;
  if( rc==SQLITE_OK && pCsr->pDeferred ){
    rc = fts3CursorSeek(0, pCsr);
    if( rc==SQLITE_OK ){
      sqlite3Fts3FreeDeferredDoclists(pCsr);
      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 expression passed as an
** argument.
*/
int sqlite3Fts3EvalNext(Fts3Cursor *pCsr, Fts3Expr *pExpr){
  int rc = SQLITE_OK;             /* Return Code */
  assert( pCsr->isEof==0 );
  assert( pCsr->bIncremental );
  if( pExpr==0 ){
    pCsr->isEof = 1;
  }else{
    do {
      sqlite3_reset(pCsr->pStmt);
      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;
}

int sqlite3Fts3EvalFinish(Fts3Cursor *pCsr, Fts3Expr *pExpr){
  return SQLITE_OK;
}

sqlite3_int64 sqlite3Fts3EvalDocid(Fts3Cursor *pCsr, Fts3Expr *pExpr){
  return pExpr->iDocid;
}

/*
** Return a pointer to the entire doclist, including positions, associated 
** with the phrase passed as the second argument.
*/
int sqlite3Fts3EvalPhraseDoclist(
  Fts3Cursor *pCsr,               /* FTS3 cursor object */
  Fts3Expr *pExpr,                /* Phrase to return doclist for */
  const char **ppList,            /* OUT: Buffer containing doclist */
  int *pnList                     /* OUT: Size of returned buffer, in bytes */
){
  int rc = SQLITE_OK;
  Fts3Phrase *pPhrase = pExpr->pPhrase;

  if( pPhrase->bIncr ){
    /* This phrase was being loaded from disk incrementally. But the 
    ** matchinfo() function requires that the entire doclist be loaded into
    ** memory. This block loads the doclist into memory and modifies the
    ** Fts3Phrase structure so that it does not use the incremental strategy.
    */
    TESTONLY( int bEof = pExpr->bEof; )
    TESTONLY( int bStart = pExpr->bStart; )
    sqlite3_int64 iDocid = pExpr->iDocid;

    sqlite3Fts3EvalPhraseCleanup(pPhrase);
    pExpr->iDocid = 0;

    rc = sqlite3Fts3EvalStart(pCsr, pExpr, 0);
    assert( pExpr->bEof==bEof );
    assert( pExpr->bStart==bStart );
    assert( rc!=SQLITE_OK || pPhrase->bIncr==0 );
    if( pExpr->bStart && !pExpr->bEof ){
      pExpr->bStart = 0;
      while( rc==SQLITE_OK && pExpr->bEof==0 && pExpr->iDocid!=iDocid ){
        fts3EvalNext(pCsr, pExpr, &rc);
      }
    }
  }

  *pnList = pPhrase->doclist.nAll;
  *ppList = pPhrase->doclist.aAll;
  return rc;
}

char *sqlite3Fts3EvalPhrasePoslist(
  Fts3Cursor *pCsr,               /* FTS3 cursor object */
  Fts3Expr *pExpr,                /* Phrase to return doclist for */
  sqlite3_int64 iDocid,           /* Docid to return position list 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!=iDocid
   || (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);
}

void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *pPhrase){
  int i;
  sqlite3_free(pPhrase->doclist.aAll);
  memset(&pPhrase->doclist, 0, sizeof(Fts3Doclist));
  for(i=0; i<pPhrase->nToken; i++){
    fts3SegReaderCursorFree(pPhrase->aToken[i].pSegcsr);
    pPhrase->aToken[i].pSegcsr = 0;
  }
}

#endif

Changes to ext/fts3/fts3Int.h.

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/*
** 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])))






/*
** 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

/*
................................................................................

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


typedef struct Fts3SegFilter Fts3SegFilter;
typedef struct Fts3DeferredToken Fts3DeferredToken;
typedef struct Fts3SegReader Fts3SegReader;
typedef struct Fts3SegReaderCursor Fts3SegReaderCursor;

/*
** 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 Fts3Cursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  i16 eSearch;                    /* Search strategy (see below) */
  u8 isEof;                       /* True if at End Of Results */
  u8 isRequireSeek;               /* True if must seek pStmt to %_content row */
  sqlite3_stmt *pStmt;            /* Prepared statement in use by the cursor */
  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 */
  int desc;                       /* True to sort in descending order */
................................................................................
** 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 */












/*
** 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 */
  Fts3SegReaderCursor *pSegcsr;   /* Segment-reader for this token */
  Fts3DeferredToken *pDeferred;   /* Deferred token object for this token */

};

struct Fts3Phrase {
  /* Variables populated by fts3_expr.c when parsing a MATCH expression */
  int nToken;                /* Number of tokens in the phrase */
  int iColumn;               /* Index of column this phrase must match */


  int isLoaded;              /* True if aDoclist/nDoclist are initialized. */
  char *aDoclist;            /* Buffer containing doclist */
  int nDoclist;              /* Size of aDoclist in bytes */
  sqlite3_int64 iCurrent;
  char *pCurrent;







  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 
................................................................................
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 */






};

/*
** 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:
**
................................................................................
char *sqlite3Fts3DeferredDoclist(Fts3DeferredToken *, int *);
void sqlite3Fts3SegmentsClose(Fts3Table *);

/* Special values interpreted by sqlite3SegReaderCursor() */
#define FTS3_SEGCURSOR_PENDING        -1
#define FTS3_SEGCURSOR_ALL            -2

int sqlite3Fts3SegReaderStart(Fts3Table*, Fts3SegReaderCursor*, Fts3SegFilter*);
int sqlite3Fts3SegReaderStep(Fts3Table *, Fts3SegReaderCursor *);
void sqlite3Fts3SegReaderFinish(Fts3SegReaderCursor *);

int sqlite3Fts3SegReaderCursor(
    Fts3Table *, int, int, const char *, int, int, int, Fts3SegReaderCursor *);

/* 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
................................................................................
struct Fts3SegFilter {
  const char *zTerm;
  int nTerm;
  int iCol;
  int flags;
};

struct Fts3SegReaderCursor {
  /* 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 */



  /* Cost of running this iterator. Used by fts3.c only. */
  int nCost;



  /* 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 *);

char *sqlite3Fts3FindPositions(Fts3Cursor *, Fts3Expr *, sqlite3_int64, int);
int sqlite3Fts3ExprLoadDoclist(Fts3Cursor *, Fts3Expr *);
int sqlite3Fts3ExprLoadFtDoclist(Fts3Cursor *, Fts3Expr *, char **, int *);
int sqlite3Fts3ExprNearTrim(Fts3Expr *, Fts3Expr *, int);

/* fts3_tokenizer.c */
const char *sqlite3Fts3NextToken(const char *, int *);
int sqlite3Fts3InitHashTable(sqlite3 *, Fts3Hash *, const char *);
................................................................................
int sqlite3Fts3ExprInitTestInterface(sqlite3 *db);
int sqlite3Fts3InitTerm(sqlite3 *db);
#endif

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


























#endif /* _FTSINT_H */







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/*
** 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

/*
................................................................................

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 Fts3Cursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  i16 eSearch;                    /* Search strategy (see below) */
  u8 isEof;                       /* True if at End Of Results */
  u8 isRequireSeek;               /* True if must seek pStmt to %_content row */
  sqlite3_stmt *pStmt;            /* Prepared statement in use by the cursor */
  Fts3Expr *pExpr;                /* Parsed MATCH query string */
  int bIncremental;               /* True to use incremental querying */
  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 */
  int desc;                       /* True to sort in descending order */
................................................................................
** 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 */

  sqlite3_int64 iDocid;          /* Current docid (if p!=0) */
  char *pNextDocid;              /* Pointer to next docid */
  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 */

#if 1
  int isLoaded;              /* True if aDoclist/nDoclist are initialized. */
  char *aDoclist;            /* Buffer containing doclist */
  int nDoclist;              /* Size of aDoclist in bytes */
  sqlite3_int64 iCurrent;
  char *pCurrent;
#endif

  /* 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 
................................................................................
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 */
};

/*
** 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:
**
................................................................................
char *sqlite3Fts3DeferredDoclist(Fts3DeferredToken *, int *);
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
................................................................................
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 *);


int sqlite3Fts3ExprLoadDoclist(Fts3Cursor *, Fts3Expr *);
int sqlite3Fts3ExprLoadFtDoclist(Fts3Cursor *, Fts3Expr *, char **, int *);
int sqlite3Fts3ExprNearTrim(Fts3Expr *, Fts3Expr *, int);

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

int sqlite3Fts3EvalPhraseCache(Fts3Cursor *, Fts3Phrase *);
sqlite3_int64 sqlite3Fts3EvalDocid(Fts3Cursor *, Fts3Expr *);
int sqlite3Fts3EvalPhraseDoclist(Fts3Cursor*, Fts3Expr*, const char**,int*);
void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *);

int sqlite3Fts3EvalStart(Fts3Cursor *, Fts3Expr *, int);
int sqlite3Fts3EvalNext(Fts3Cursor *pCsr, Fts3Expr *pExpr);
int sqlite3Fts3MsrIncrStart(
    Fts3Table*, Fts3MultiSegReader*, int, const char*, int);
int sqlite3Fts3MsrIncrNext(
    Fts3Table *, Fts3MultiSegReader *, sqlite3_int64 *, char **, int *);
char *sqlite3Fts3EvalPhrasePoslist(
  Fts3Cursor *, Fts3Expr *, sqlite3_int64, int iCol); 
int sqlite3Fts3MsrOvfl(Fts3Cursor *, Fts3MultiSegReader *, int *);

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

#endif /* _FTSINT_H */

Changes to ext/fts3/fts3_aux.c.

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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 */
  Fts3SegReaderCursor 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 */







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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 */

Changes to ext/fts3/fts3_expr.c.

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** 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);


    if( p->pPhrase ) sqlite3_free(p->pPhrase->aDoclist);

    sqlite3_free(p);
  }
}

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







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** 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);
    if( p->pPhrase ){
      sqlite3Fts3EvalPhraseCleanup(p->pPhrase);
      sqlite3_free(p->pPhrase->aDoclist);
    }
    sqlite3_free(p);
  }
}

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

Changes to ext/fts3/fts3_snippet.c.

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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 = sqlite3Fts3FindPositions(p->pCsr, pExpr, p->pCsr->iPrevId, p->iCol);
  if( pCsr ){
    int iFirst = 0;
    pPhrase->pList = pCsr;
    fts3GetDeltaPosition(&pCsr, &iFirst);
    pPhrase->pHead = pCsr;
    pPhrase->pTail = pCsr;
    pPhrase->iHead = iFirst;
................................................................................
*/
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;
  Fts3Cursor *pCsr = p->pCursor;
  Fts3Phrase *pPhrase = pExpr->pPhrase; 
  char *pIter;
  char *pEnd;
  char *pFree = 0;
  u32 *aOut = &p->aMatchinfo[3*iPhrase*p->nCol];

  assert( pPhrase->isLoaded );

  if( pCsr->pDeferred ){
    int ii;
    for(ii=0; ii<pPhrase->nToken; ii++){
      if( pPhrase->aToken[ii].bFulltext ) break;
    }
    if( ii<pPhrase->nToken ){
      int nFree = 0;
      int rc = sqlite3Fts3ExprLoadFtDoclist(pCsr, pExpr, &pFree, &nFree);
      if( rc!=SQLITE_OK ) return rc;
      pIter = pFree;
      pEnd = &pFree[nFree];
    }else{
      int iCol;                   /* Column index */
      for(iCol=0; iCol<p->nCol; iCol++){
        aOut[iCol*3 + 1] = (u32)p->nDoc;
        aOut[iCol*3 + 2] = (u32)p->nDoc;
      }
      return SQLITE_OK;
    }
  }else{


    pIter = pPhrase->aDoclist;
    pEnd = &pPhrase->aDoclist[pPhrase->nDoclist];
  }





  /* Fill in the global hit count matrix row for this phrase. */
  while( pIter<pEnd ){
    while( *pIter++ & 0x80 );      /* Skip past docid. */
    fts3LoadColumnlistCounts(&pIter, &aOut[1], 1);
  }

  sqlite3_free(pFree);

  return SQLITE_OK;
}

/*
** 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.
................................................................................
  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++) p->aMatchinfo[iStart+i*3] = 0;

  if( pExpr->pPhrase->aDoclist ){
    char *pCsr;

    pCsr = sqlite3Fts3FindPositions(p->pCursor, pExpr, p->pCursor->iPrevId, -1);
    if( pCsr ){
      fts3LoadColumnlistCounts(&pCsr, &p->aMatchinfo[iStart], 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 */
  char *pRead;                    /* Cursor used to iterate through aDoclist */
  int iPosOffset;                 /* Tokens count up to end of this phrase */
  int iCol;                       /* Current column number */

  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 ){
    pIter->iCol = LCS_ITERATOR_FINISHED;
    rc = 1;
  }else{
    if( iRead==1 ){
      pRead += sqlite3Fts3GetVarint(pRead, &iRead);
      pIter->iCol = (int)iRead;
      pIter->iPos = pIter->iPosOffset;
      pRead += sqlite3Fts3GetVarint(pRead, &iRead);
      rc = 1;
    }
    pIter->iPos += (int)(iRead-2);
  }

  pIter->pRead = pRead;
  return rc;
}
  
................................................................................
** undefined.
*/
static int fts3MatchinfoLcs(Fts3Cursor *pCsr, MatchInfo *pInfo){
  LcsIterator *aIter;
  int i;
  int iCol;
  int nToken = 0;


  /* 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;
    pIter->pRead = sqlite3Fts3FindPositions(pCsr,pIter->pExpr,pCsr->iPrevId,-1);
    if( pIter->pRead ){
      pIter->iPos = pIter->iPosOffset;
      fts3LcsIteratorAdvance(&aIter[i]);
    }else{
      pIter->iCol = LCS_ITERATOR_FINISHED;
    }
  }

  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 */

    /* Loop through the iterators in aIter[]. Set nLive to the number of
    ** iterators that point to a position-list corresponding to column iCol.
    */
    for(i=0; i<pInfo->nPhrase; i++){
      assert( aIter[i].iCol>=iCol );
      if( aIter[i].iCol==iCol ) nLive++;
    }

    /* The following loop runs until all iterators in aIter[] have finished
    ** iterating through positions in column iCol. Exactly one of the 
    ** iterators is advanced each time the body of the loop is run.
    */
    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( iCol!=pIter->iCol ){  
          /* 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 = sqlite3Fts3FindPositions(p->pCsr, pExpr, p->iDocid, p->iCol);
  nTerm = pExpr->pPhrase->nToken;
  if( pList ){
    fts3GetDeltaPosition(&pList, &iPos);
    assert( iPos>=0 );
  }

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







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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->pCsr->iPrevId,p->iCol);
  if( pCsr ){
    int iFirst = 0;
    pPhrase->pList = pCsr;
    fts3GetDeltaPosition(&pCsr, &iFirst);
    pPhrase->pHead = pCsr;
    pPhrase->pTail = pCsr;
    pPhrase->iHead = iFirst;
................................................................................
*/
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;





  u32 *aOut = &p->aMatchinfo[3*iPhrase*p->nCol];



  if( pExpr->bDeferred ){











    int iCol;                   /* Column index */
    for(iCol=0; iCol<p->nCol; iCol++){
      aOut[iCol*3 + 1] = (u32)p->nDoc;
      aOut[iCol*3 + 2] = (u32)p->nDoc;
    }


  }else{
    char *pIter;
    char *pEnd;
    int n;
    int rc = sqlite3Fts3EvalPhraseDoclist(

        p->pCursor, pExpr, (const char **)&pIter, &n
    );
    if( rc!=SQLITE_OK ) return rc;
    pEnd = &pIter[n];

    /* Fill in the global hit count matrix row for this phrase. */
    while( pIter<pEnd ){
      while( *pIter++ & 0x80 );      /* Skip past docid. */
      fts3LoadColumnlistCounts(&pIter, &aOut[1], 1);
    }
  }


  return SQLITE_OK;
}

/*
** 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.
................................................................................
  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;
  sqlite3_int64 iDocid = p->pCursor->iPrevId;

  for(i=0; i<p->nCol; i++){
    char *pCsr;
    pCsr = sqlite3Fts3EvalPhrasePoslist(p->pCursor, pExpr, iDocid, 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;
}
  
................................................................................
** undefined.
*/
static int fts3MatchinfoLcs(Fts3Cursor *pCsr, MatchInfo *pInfo){
  LcsIterator *aIter;
  int i;
  int iCol;
  int nToken = 0;
  sqlite3_int64 iDocid = pCsr->iPrevId;

  /* 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, iDocid, 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->iDocid, p->iCol);
  nTerm = pExpr->pPhrase->nToken;
  if( pList ){
    fts3GetDeltaPosition(&pList, &iPos);
    assert( iPos>=0 );
  }

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

Changes to ext/fts3/fts3_term.c.

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  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 */
  Fts3SegReaderCursor 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 */







|







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  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 */

Changes to ext/fts3/fts3_write.c.

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  Fts3SegReader *pReader,         /* Segment-reader handle */
  int *pnCost                     /* IN/OUT: Number of bytes read */
){
  Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
  int rc = SQLITE_OK;             /* Return code */
  int nCost = 0;                  /* Cost in bytes to return */
  int pgsz = p->nPgsz;            /* Database page size */



  /* If this seg-reader is reading the pending-terms table, or if all data
  ** for the segment is stored on the root page of the b-tree, then the cost
  ** is zero. In this case all required data is already in main memory.
  */
  if( p->bHasStat 
   && !fts3SegReaderIsPending(pReader) 
................................................................................
      }
    }
  }

  *pnCost += nCost;
  return rc;
}



































/*
** Free all allocations associated with the iterator passed as the 
** second argument.
*/
void sqlite3Fts3SegReaderFree(Fts3SegReader *pReader){
  if( pReader && !fts3SegReaderIsPending(pReader) ){
................................................................................
    p = &pList[1];
    p += sqlite3Fts3GetVarint32(p, &iCurrent);
  }

  *ppList = pList;
  *pnList = nList;
}



































































































int sqlite3Fts3SegReaderStart(
  Fts3Table *p,                   /* Virtual table handle */
  Fts3SegReaderCursor *pCsr,      /* Cursor object */
  Fts3SegFilter *pFilter          /* Restrictions on range of iteration */
){
  int i;

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

................................................................................
      pCsr->apSegment, pCsr->nSegment, pCsr->nSegment, fts3SegReaderCmp);

  return SQLITE_OK;
}

int sqlite3Fts3SegReaderStep(
  Fts3Table *p,                   /* Virtual table handle */
  Fts3SegReaderCursor *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);
................................................................................
      }
    }
    pCsr->nAdvance = nMerge;
  }while( rc==SQLITE_OK );

  return rc;
}


void sqlite3Fts3SegReaderFinish(
  Fts3SegReaderCursor *pCsr       /* Cursor object */
){
  if( pCsr ){
    int i;
    for(i=0; i<pCsr->nSegment; i++){
      sqlite3Fts3SegReaderFree(pCsr->apSegment[i]);
    }
    sqlite3_free(pCsr->apSegment);
................................................................................
*/
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 */
  Fts3SegReaderCursor 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 );
................................................................................
        rc = fts3PendingListAppendVarint(&pDef->pList, 0);
      }
    }
  }

  return rc;
}




























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







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  Fts3SegReader *pReader,         /* Segment-reader handle */
  int *pnCost                     /* IN/OUT: Number of bytes read */
){
  Fts3Table *p = (Fts3Table*)pCsr->base.pVtab;
  int rc = SQLITE_OK;             /* Return code */
  int nCost = 0;                  /* Cost in bytes to return */
  int pgsz = p->nPgsz;            /* Database page size */

  assert( pgsz>0 );

  /* If this seg-reader is reading the pending-terms table, or if all data
  ** for the segment is stored on the root page of the b-tree, then the cost
  ** is zero. In this case all required data is already in main memory.
  */
  if( p->bHasStat 
   && !fts3SegReaderIsPending(pReader) 
................................................................................
      }
    }
  }

  *pnCost += nCost;
  return rc;
}

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);
        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) ){
................................................................................
    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;

  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);
      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++){
    fts3SegReaderFirstDocid(pCsr->apSegment[i]);
  }

  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 rc = SQLITE_OK;
  int nMerge = pMsr->nAdvance;
  Fts3SegReader **apSegment = pMsr->apSegment;

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

  while( 1 ){
    Fts3SegReader *pSeg;
    fts3SegReaderSort(pMsr->apSegment, nMerge, nMerge, fts3SegReaderDoclistCmp);
    pSeg = pMsr->apSegment[0];

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

      fts3SegReaderNextDocid(apSegment[0], &pList, &nList);
      j = 1;
      while( j<nMerge
        && apSegment[j]->pOffsetList
        && apSegment[j]->iDocid==iDocid
      ){
        fts3SegReaderNextDocid(apSegment[j], 0, 0);
      }

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

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

  return rc;
}

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;

................................................................................
      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);
................................................................................
      }
    }
    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);
................................................................................
*/
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 );
................................................................................
        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 */

Changes to test/fts3defer.test.

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ifcapable !fts3 {
  finish_test
  return
}

set sqlite_fts3_enable_parentheses 1



set ::testprefix fts3defer

#--------------------------------------------------------------------------
# Test cases fts3defer-1.* are the "warm body" cases. The database contains
# one row with 15000 instances of the token "a". This makes the doclist for
# "a" so large that FTS3 will avoid loading it in most cases.
#
................................................................................

  do_select_test 1.1 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'jk xnxhf'
  } {13 29 40 47 48 52 63 92}
  do_select_test 1.2 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'jk eh'
  } {100}
if {$tn==3} breakpoint
  do_select_test 1.3 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'jk ubwrfqnbjf'
  } {7 70 98}
  do_select_test 1.4 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'duszemmzl jk'
  } {3 5 8 10 13 18 20 23 32 37 41 43 55 60 65 67 72 74 76 81 94 96 97}
  do_select_test 1.5 {
................................................................................
  } {68 100}
  do_select_test 1.9 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'zm ubwrfqnbjf'
  } {7 70 98}
  do_select_test 1.10 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'z* vgsld'
  } {10 13 17 31 35 51 58 88 89 90 93 100}


  do_select_test 1.11 {
    SELECT rowid FROM t1 
    WHERE t1 MATCH '(
      zdu OR zexh OR zf OR zhbrzadb OR zidhxhbtv OR 
      zk OR zkhdvkw OR zm OR zsmhnf
    ) vgsld'
  } {10 13 17 31 35 51 58 88 89 90 93 100}


  do_select_test 2.1 {
    SELECT rowid FROM t1 WHERE t1 MATCH '"zm agmckuiu"'
  } {3 24 52 53}
  do_select_test 2.2 {
    SELECT rowid FROM t1 WHERE t1 MATCH '"zm zf"'
  } {33 53 75 88 101}
................................................................................
  # The following block of tests runs normally with FTS3 or FTS4 without the
  # long doclists zeroed. And with OOM-injection for FTS4 with long doclists
  # zeroed. Change this by messing with the [set dmt_modes] commands above.
  #
  foreach DO_MALLOC_TEST $dmt_modes {
    
    # Phrase search.

    do_select_test 5.$DO_MALLOC_TEST.1 {
      SELECT rowid FROM t1 WHERE t1 MATCH '"jk mjpavjuhw"'
    } {8 15 36 64 67 72}

    # Multiple tokens search.
    do_select_test 5.$DO_MALLOC_TEST.2 {
      SELECT rowid FROM t1 WHERE t1 MATCH 'duszemmzl zm'
................................................................................
  } {10}
  do_select_test 6.2.1 {
    SELECT rowid FROM t1 WHERE t1 MATCH '"jk xduvfhk"'
  } {8}
  do_select_test 6.2.2 {
    SELECT rowid FROM t1 WHERE t1 MATCH '"zm azavwm"'
  } {15 26 92 96}

  do_select_test 6.2.3 {
    SELECT rowid FROM t1 WHERE t1 MATCH '"jk xduvfhk" OR "zm azavwm"'
  } {8 15 26 92 96}
}


set testprefix fts3defer

do_execsql_test 3.1 {
  CREATE VIRTUAL TABLE x1 USING fts4(a, b);
  INSERT INTO x1 VALUES('a b c', 'd e f');
  INSERT INTO x1 SELECT * FROM x1;







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ifcapable !fts3 {
  finish_test
  return
}

set sqlite_fts3_enable_parentheses 1

set fts3_simple_deferred_tokens_only 1

set ::testprefix fts3defer

#--------------------------------------------------------------------------
# Test cases fts3defer-1.* are the "warm body" cases. The database contains
# one row with 15000 instances of the token "a". This makes the doclist for
# "a" so large that FTS3 will avoid loading it in most cases.
#
................................................................................

  do_select_test 1.1 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'jk xnxhf'
  } {13 29 40 47 48 52 63 92}
  do_select_test 1.2 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'jk eh'
  } {100}

  do_select_test 1.3 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'jk ubwrfqnbjf'
  } {7 70 98}
  do_select_test 1.4 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'duszemmzl jk'
  } {3 5 8 10 13 18 20 23 32 37 41 43 55 60 65 67 72 74 76 81 94 96 97}
  do_select_test 1.5 {
................................................................................
  } {68 100}
  do_select_test 1.9 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'zm ubwrfqnbjf'
  } {7 70 98}
  do_select_test 1.10 {
    SELECT rowid FROM t1 WHERE t1 MATCH 'z* vgsld'
  } {10 13 17 31 35 51 58 88 89 90 93 100}

  if { $fts3_simple_deferred_tokens_only==0 } {
    do_select_test 1.11 {
      SELECT rowid FROM t1 
      WHERE t1 MATCH '(
        zdu OR zexh OR zf OR zhbrzadb OR zidhxhbtv OR 
        zk OR zkhdvkw OR zm OR zsmhnf
      ) vgsld'
    } {10 13 17 31 35 51 58 88 89 90 93 100}
  }

  do_select_test 2.1 {
    SELECT rowid FROM t1 WHERE t1 MATCH '"zm agmckuiu"'
  } {3 24 52 53}
  do_select_test 2.2 {
    SELECT rowid FROM t1 WHERE t1 MATCH '"zm zf"'
  } {33 53 75 88 101}
................................................................................
  # The following block of tests runs normally with FTS3 or FTS4 without the
  # long doclists zeroed. And with OOM-injection for FTS4 with long doclists
  # zeroed. Change this by messing with the [set dmt_modes] commands above.
  #
  foreach DO_MALLOC_TEST $dmt_modes {
    
    # Phrase search.
    #
    do_select_test 5.$DO_MALLOC_TEST.1 {
      SELECT rowid FROM t1 WHERE t1 MATCH '"jk mjpavjuhw"'
    } {8 15 36 64 67 72}

    # Multiple tokens search.
    do_select_test 5.$DO_MALLOC_TEST.2 {
      SELECT rowid FROM t1 WHERE t1 MATCH 'duszemmzl zm'
................................................................................
  } {10}
  do_select_test 6.2.1 {
    SELECT rowid FROM t1 WHERE t1 MATCH '"jk xduvfhk"'
  } {8}
  do_select_test 6.2.2 {
    SELECT rowid FROM t1 WHERE t1 MATCH '"zm azavwm"'
  } {15 26 92 96}
  if {$fts3_simple_deferred_tokens_only==0} {
    do_select_test 6.2.3 {
      SELECT rowid FROM t1 WHERE t1 MATCH '"jk xduvfhk" OR "zm azavwm"'
    } {8 15 26 92 96}
  }
}

set testprefix fts3defer

do_execsql_test 3.1 {
  CREATE VIRTUAL TABLE x1 USING fts4(a, b);
  INSERT INTO x1 VALUES('a b c', 'd e f');
  INSERT INTO x1 SELECT * FROM x1;

Changes to test/permutations.test.

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} -files {
  fts3aa.test fts3ab.test fts3ac.test fts3ad.test fts3ae.test
  fts3af.test fts3ag.test fts3ah.test fts3ai.test fts3aj.test
  fts3ak.test fts3al.test fts3am.test fts3an.test fts3ao.test
  fts3atoken.test fts3b.test fts3c.test fts3cov.test fts3d.test
  fts3defer.test fts3defer2.test fts3e.test fts3expr.test fts3expr2.test 
  fts3near.test fts3query.test fts3shared.test fts3snippet.test 


  fts3fault.test fts3malloc.test fts3matchinfo.test

  fts3aux1.test fts3comp1.test
}









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} -files {
  fts3aa.test fts3ab.test fts3ac.test fts3ad.test fts3ae.test
  fts3af.test fts3ag.test fts3ah.test fts3ai.test fts3aj.test
  fts3ak.test fts3al.test fts3am.test fts3an.test fts3ao.test
  fts3atoken.test fts3b.test fts3c.test fts3cov.test fts3d.test
  fts3defer.test fts3defer2.test fts3e.test fts3expr.test fts3expr2.test 
  fts3near.test fts3query.test fts3shared.test fts3snippet.test 
  fts3sort.test

  fts3fault.test fts3malloc.test fts3matchinfo.test

  fts3aux1.test fts3comp1.test
}