/ Check-in [8a208223]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Change the fts3 snippet function to return (hopefully) more relevant snippets in less time.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 8a208223a74d451f60d9cd707d63fb7d157d1737
User & Date: dan 2010-01-06 17:19:22
Context
2010-01-06
18:36
Fix a segfault that can occur following an OOM in the FTS3 snippet() function check-in: c7e5966e user: dan tags: trunk
17:19
Change the fts3 snippet function to return (hopefully) more relevant snippets in less time. check-in: 8a208223 user: dan tags: trunk
13:07
Fix an issue with lemon generating incorrect grammars. This issue does not effect SQLite. check-in: 077a6bee user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to ext/fts3/fts3.c.

1704
1705
1706
1707
1708
1709
1710




































































1711
1712
1713
1714
1715
1716
1717
....
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775

1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
....
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
....
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
....
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
....
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
....
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
    *paOut = pOut;
    *pnOut = nOut;
  }else{
    sqlite3_free(pOut);
  }
  return rc;
}





































































/*
** Evaluate the full-text expression pExpr against fts3 table pTab. Store
** the resulting doclist in *paOut and *pnOut.
*/
static int evalFts3Expr(
  Fts3Table *p,                   /* Virtual table handle */
................................................................................
            || pExpr->eType==FTSQUERY_AND  || pExpr->eType==FTSQUERY_NOT
        );
        switch( pExpr->eType ){
          case FTSQUERY_NEAR: {
            Fts3Expr *pLeft;
            Fts3Expr *pRight;
            int mergetype = isReqPos ? MERGE_POS_NEAR : MERGE_NEAR;
            int nParam1;
            int nParam2;
            char *aBuffer;
           
            if( pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR ){
              mergetype = MERGE_POS_NEAR;
            }
            pLeft = pExpr->pLeft;
            while( pLeft->eType==FTSQUERY_NEAR ){ 
              pLeft=pLeft->pRight;
            }
            pRight = pExpr->pRight;
            assert( pRight->eType==FTSQUERY_PHRASE );
            assert( pLeft->eType==FTSQUERY_PHRASE );

            nParam1 = pExpr->nNear+1;
            nParam2 = nParam1+pLeft->pPhrase->nToken+pRight->pPhrase->nToken-2;
            aBuffer = sqlite3_malloc(nLeft+nRight+1);
            rc = fts3DoclistMerge(mergetype, nParam1, nParam2, aBuffer,
                pnOut, aLeft, nLeft, aRight, nRight

            );
            if( rc!=SQLITE_OK ){
              sqlite3_free(aBuffer);
            }else{
              *paOut = aBuffer;
            }
            sqlite3_free(aLeft);
            break;
          }

          case FTSQUERY_OR: {
            /* Allocate a buffer for the output. The maximum size is the
            ** sum of the sizes of the two input buffers. The +1 term is
................................................................................
          }
          while( iThis<iCol ){
            fts3ColumnlistCopy(0, &pCsr);
            if( *pCsr==0x00 ) return 0;
            pCsr++;
            pCsr += sqlite3Fts3GetVarint32(pCsr, &iThis);
          }
          if( iCol==iThis ) return pCsr;
        }
        return 0;
      }
    }
  }

  return 0;
................................................................................
  int nVal,                       /* Size of apVal[] array */
  sqlite3_value **apVal           /* Array of arguments */
){
  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
  const char *zStart = "<b>";
  const char *zEnd = "</b>";
  const char *zEllipsis = "<b>...</b>";

  /* There must be at least one argument passed to this function (otherwise
  ** the non-overloaded version would have been called instead of this one).
  */
  assert( nVal>=1 );

  if( nVal>4 ){
    sqlite3_result_error(pContext, 
        "wrong number of arguments to function snippet()", -1);
    return;
  }
  if( fts3FunctionArg(pContext, "snippet", apVal[0], &pCsr) ) return;

  switch( nVal ){
    case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
    case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
    case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
  }
  if( !zEllipsis || !zEnd || !zStart ){
    sqlite3_result_error_nomem(pContext);
  }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
    sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis);
  }
}

/*
** Implementation of the snippet2() function for FTS3
*/
static void fts3Snippet2Func(
  sqlite3_context *pContext,      /* SQLite function call context */
  int nVal,                       /* Size of apVal[] array */
  sqlite3_value **apVal           /* Array of arguments */
){
  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
  const char *zStart = "<b>";
  const char *zEnd = "</b>";
  const char *zEllipsis = "<b>...</b>";
  int iCol = -1;
  int nToken = 10;

  /* There must be at least one argument passed to this function (otherwise
  ** the non-overloaded version would have been called instead of this one).
  */
  assert( nVal>=1 );

  if( nVal>6 ){
................................................................................
    case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
    case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
    case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
  }
  if( !zEllipsis || !zEnd || !zStart ){
    sqlite3_result_error_nomem(pContext);
  }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
    sqlite3Fts3Snippet2(pContext, pCsr, zStart, zEnd, zEllipsis, iCol, nToken);
  }
}

/*
** Implementation of the offsets() function for FTS3
*/
static void fts3OffsetsFunc(
................................................................................
  void **ppArg                    /* Unused */
){
  struct Overloaded {
    const char *zName;
    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
  } aOverload[] = {
    { "snippet", fts3SnippetFunc },
    { "snippet2", fts3Snippet2Func },
    { "offsets", fts3OffsetsFunc },
    { "optimize", fts3OptimizeFunc },
    { "matchinfo", fts3MatchinfoFunc },
  };
  int i;                          /* Iterator variable */

  UNUSED_PARAMETER(pVtab);
................................................................................
  /* Create the virtual table wrapper around the hash-table and overload 
  ** the two scalar functions. If this is successful, register the
  ** module with sqlite.
  */
  if( SQLITE_OK==rc 
   && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet2", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
  ){
    return sqlite3_create_module_v2(
        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
    );







>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







<
<
<












|
|
<
<
|
>

<
<
<
<
<







 







|







 







<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<

|







 







|







 







<







 







<







1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
....
1817
1818
1819
1820
1821
1822
1823



1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837


1838
1839
1840





1841
1842
1843
1844
1845
1846
1847
....
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
....
2171
2172
2173
2174
2175
2176
2177





































2178
2179
2180
2181
2182
2183
2184
2185
2186
....
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
....
2297
2298
2299
2300
2301
2302
2303

2304
2305
2306
2307
2308
2309
2310
....
2446
2447
2448
2449
2450
2451
2452

2453
2454
2455
2456
2457
2458
2459
    *paOut = pOut;
    *pnOut = nOut;
  }else{
    sqlite3_free(pOut);
  }
  return rc;
}

static int fts3NearMerge(
  int mergetype,                  /* MERGE_POS_NEAR or MERGE_NEAR */
  int nNear,                      /* Parameter to NEAR operator */
  int nTokenLeft,                 /* Number of tokens in LHS phrase arg */
  char *aLeft,                    /* Doclist for LHS (incl. positions) */
  int nLeft,                      /* Size of LHS doclist in bytes */
  int nTokenRight,                /* As nTokenLeft */
  char *aRight,                   /* As aLeft */
  int nRight,                     /* As nRight */
  char **paOut,                   /* OUT: Results of merge (malloced) */
  int *pnOut                      /* OUT: Sized of output buffer */
){
  char *aOut;
  int rc;

  assert( mergetype==MERGE_POS_NEAR || MERGE_NEAR );

  aOut = sqlite3_malloc(nLeft+nRight+1);
  if( aOut==0 ){
    rc = SQLITE_NOMEM;
  }else{
    rc = fts3DoclistMerge(mergetype, nNear+nTokenRight, nNear+nTokenLeft, 
      aOut, pnOut, aLeft, nLeft, aRight, nRight
    );
    if( rc!=SQLITE_OK ){
      sqlite3_free(aOut);
      aOut = 0;
    }
  }

  *paOut = aOut;
  return rc;
}

int sqlite3Fts3ExprNearTrim(Fts3Expr *pLeft, Fts3Expr *pRight, int nNear){
  int rc;
  if( pLeft->aDoclist==0 || pRight->aDoclist==0 ){
    sqlite3_free(pLeft->aDoclist);
    sqlite3_free(pRight->aDoclist);
    pRight->aDoclist = 0;
    pLeft->aDoclist = 0;
    rc = SQLITE_OK;
  }else{
    char *aOut;
    int nOut;

    rc = fts3NearMerge(MERGE_POS_NEAR, nNear, 
        pLeft->pPhrase->nToken, pLeft->aDoclist, pLeft->nDoclist,
        pRight->pPhrase->nToken, pRight->aDoclist, pRight->nDoclist,
        &aOut, &nOut
    );
    if( rc!=SQLITE_OK ) return rc;
    sqlite3_free(pRight->aDoclist);
    pRight->aDoclist = aOut;
    pRight->nDoclist = nOut;

    rc = fts3NearMerge(MERGE_POS_NEAR, nNear, 
        pRight->pPhrase->nToken, pRight->aDoclist, pRight->nDoclist,
        pLeft->pPhrase->nToken, pLeft->aDoclist, pLeft->nDoclist,
        &aOut, &nOut
    );
    sqlite3_free(pLeft->aDoclist);
    pLeft->aDoclist = aOut;
    pLeft->nDoclist = nOut;
  }
  return rc;
}

/*
** Evaluate the full-text expression pExpr against fts3 table pTab. Store
** the resulting doclist in *paOut and *pnOut.
*/
static int evalFts3Expr(
  Fts3Table *p,                   /* Virtual table handle */
................................................................................
            || pExpr->eType==FTSQUERY_AND  || pExpr->eType==FTSQUERY_NOT
        );
        switch( pExpr->eType ){
          case FTSQUERY_NEAR: {
            Fts3Expr *pLeft;
            Fts3Expr *pRight;
            int mergetype = isReqPos ? MERGE_POS_NEAR : MERGE_NEAR;



           
            if( pExpr->pParent && pExpr->pParent->eType==FTSQUERY_NEAR ){
              mergetype = MERGE_POS_NEAR;
            }
            pLeft = pExpr->pLeft;
            while( pLeft->eType==FTSQUERY_NEAR ){ 
              pLeft=pLeft->pRight;
            }
            pRight = pExpr->pRight;
            assert( pRight->eType==FTSQUERY_PHRASE );
            assert( pLeft->eType==FTSQUERY_PHRASE );

            rc = fts3NearMerge(mergetype, pExpr->nNear, 
                pLeft->pPhrase->nToken, aLeft, nLeft,


                pRight->pPhrase->nToken, aRight, nRight,
                paOut, pnOut
            );





            sqlite3_free(aLeft);
            break;
          }

          case FTSQUERY_OR: {
            /* Allocate a buffer for the output. The maximum size is the
            ** sum of the sizes of the two input buffers. The +1 term is
................................................................................
          }
          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;
................................................................................
  int nVal,                       /* Size of apVal[] array */
  sqlite3_value **apVal           /* Array of arguments */
){
  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
  const char *zStart = "<b>";
  const char *zEnd = "</b>";
  const char *zEllipsis = "<b>...</b>";





































  int iCol = -1;
  int nToken = 15;

  /* There must be at least one argument passed to this function (otherwise
  ** the non-overloaded version would have been called instead of this one).
  */
  assert( nVal>=1 );

  if( nVal>6 ){
................................................................................
    case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
    case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
    case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
  }
  if( !zEllipsis || !zEnd || !zStart ){
    sqlite3_result_error_nomem(pContext);
  }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
    sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis, iCol, nToken);
  }
}

/*
** Implementation of the offsets() function for FTS3
*/
static void fts3OffsetsFunc(
................................................................................
  void **ppArg                    /* Unused */
){
  struct Overloaded {
    const char *zName;
    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
  } aOverload[] = {
    { "snippet", fts3SnippetFunc },

    { "offsets", fts3OffsetsFunc },
    { "optimize", fts3OptimizeFunc },
    { "matchinfo", fts3MatchinfoFunc },
  };
  int i;                          /* Iterator variable */

  UNUSED_PARAMETER(pVtab);
................................................................................
  /* Create the virtual table wrapper around the hash-table and overload 
  ** the two scalar functions. If this is successful, register the
  ** module with sqlite.
  */
  if( SQLITE_OK==rc 
   && SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))

   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
  ){
    return sqlite3_create_module_v2(
        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
    );

Changes to ext/fts3/fts3Int.h.

275
276
277
278
279
280
281

282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
int sqlite3Fts3GetVarint32(const char *, int *);
int sqlite3Fts3VarintLen(sqlite3_uint64);
void sqlite3Fts3Dequote(char *);

char *sqlite3Fts3FindPositions(Fts3Expr *, sqlite3_int64, int);
int sqlite3Fts3ExprLoadDoclist(Fts3Table *, Fts3Expr *);


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

/* fts3_snippet.c */
void sqlite3Fts3Offsets(sqlite3_context*, Fts3Cursor*);
void sqlite3Fts3Snippet(sqlite3_context*, Fts3Cursor*, 
  const char *, const char *, const char *
);
void sqlite3Fts3Snippet2(sqlite3_context *, Fts3Cursor *, const char *,
  const char *, const char *, int, int
);
void sqlite3Fts3Matchinfo(sqlite3_context *, Fts3Cursor *);

/* fts3_expr.c */
int sqlite3Fts3ExprParse(sqlite3_tokenizer *, 
  char **, int, int, const char *, int, Fts3Expr **







>










<
<
<
|







275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292



293
294
295
296
297
298
299
300
int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
int sqlite3Fts3GetVarint32(const char *, int *);
int sqlite3Fts3VarintLen(sqlite3_uint64);
void sqlite3Fts3Dequote(char *);

char *sqlite3Fts3FindPositions(Fts3Expr *, sqlite3_int64, int);
int sqlite3Fts3ExprLoadDoclist(Fts3Table *, Fts3Expr *);
int sqlite3Fts3ExprNearTrim(Fts3Expr *, Fts3Expr *, int);

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

/* fts3_snippet.c */
void sqlite3Fts3Offsets(sqlite3_context*, Fts3Cursor*);



void sqlite3Fts3Snippet(sqlite3_context *, Fts3Cursor *, const char *,
  const char *, const char *, int, int
);
void sqlite3Fts3Matchinfo(sqlite3_context *, Fts3Cursor *);

/* fts3_expr.c */
int sqlite3Fts3ExprParse(sqlite3_tokenizer *, 
  char **, int, int, const char *, int, Fts3Expr **

Changes to ext/fts3/fts3_snippet.c.

14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
...
776
777
778
779
780
781
782

783
784































785
786
787

788


789
790
791
792
793
794
795
796

797
798
799









800




801
802
803
804



805

806
807
808
809
810
811
812
...
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845

846
847

848

849
850
851
852
853
854
855
...
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920


921

922
923



















924
925
926
927
928
929
930


931
932
933
934
935
936
937
938
939

940
941
942
943

944
945

946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964

965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980






981
982
983
984
985
986
987
988
989
990
991
992
993

994
995
996
997
998
999
1000


1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013

1014
1015
1016
1017

1018
1019



1020
1021
1022
1023
1024
1025
1026
....
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
....
1048
1049
1050
1051
1052
1053
1054
1055















































1056
1057
1058
1059

1060
1061
1062
1063
1064
1065
1066
1067
1068
1069


1070
1071
1072




1073
1074
1075
1076
1077
1078
1079







1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101











1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
....
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
....
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310


1311



































1312
1313
































































































1314



























1315

1316

1317
1318





1319
1320

1321




1322



























1323
1324
1325





1326













1327
1328

1329
1330
1331

1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

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

typedef struct Snippet Snippet;

/*
** An instance of the following structure keeps track of generated
** matching-word offset information and snippets.
*/
struct Snippet {
  int nMatch;                     /* Total number of matches */
  int nAlloc;                     /* Space allocated for aMatch[] */
  struct snippetMatch {  /* One entry for each matching term */
    char snStatus;       /* Status flag for use while constructing snippets */
    short int nByte;     /* Number of bytes in the term */
    short int iCol;      /* The column that contains the match */
    short int iTerm;     /* The index in Query.pTerms[] of the matching term */
    int iToken;          /* The index of the matching document token */
    int iStart;          /* The offset to the first character of the term */
  } *aMatch;                      /* Points to space obtained from malloc */
  char *zOffset;                  /* Text rendering of aMatch[] */
  int nOffset;                    /* strlen(zOffset) */
  char *zSnippet;                 /* Snippet text */
  int nSnippet;                   /* strlen(zSnippet) */
};


/* It is not safe to call isspace(), tolower(), or isalnum() on
** hi-bit-set characters.  This is the same solution used in the
** tokenizer.
*/
static int fts3snippetIsspace(char c){
  return (c&0x80)==0 ? isspace(c) : 0;
}


/*
** A StringBuffer object holds a zero-terminated string that grows
** arbitrarily by appending.  Space to hold the string is obtained
** from sqlite3_malloc().  After any memory allocation failure, 
** StringBuffer.z is set to NULL and no further allocation is attempted.
*/
typedef struct StringBuffer {
  char *z;         /* Text of the string.  Space from malloc. */
  int nUsed;       /* Number bytes of z[] used, not counting \000 terminator */
  int nAlloc;      /* Bytes allocated for z[] */
} StringBuffer;


/*
** Initialize a new StringBuffer.
*/
static void fts3SnippetSbInit(StringBuffer *p){
  p->nAlloc = 100;
  p->nUsed = 0;
  p->z = sqlite3_malloc( p->nAlloc );
}

/*
** Append text to the string buffer.
*/
static void fts3SnippetAppend(StringBuffer *p, const char *zNew, int nNew){
  if( p->z==0 ) return;
  if( nNew<0 ) nNew = (int)strlen(zNew);
  if( p->nUsed + nNew >= p->nAlloc ){
    int nAlloc;
    char *zNew;

    nAlloc = p->nUsed + nNew + p->nAlloc;
    zNew = sqlite3_realloc(p->z, nAlloc);
    if( zNew==0 ){
      sqlite3_free(p->z);
      p->z = 0;
      return;
    }
    p->z = zNew;
    p->nAlloc = nAlloc;
  }
  memcpy(&p->z[p->nUsed], zNew, nNew);
  p->nUsed += nNew;
  p->z[p->nUsed] = 0;
}

/* If the StringBuffer ends in something other than white space, add a
** single space character to the end.
*/
static void fts3SnippetAppendWhiteSpace(StringBuffer *p){
  if( p->z && p->nUsed && !fts3snippetIsspace(p->z[p->nUsed-1]) ){
    fts3SnippetAppend(p, " ", 1);
  }
}

/* Remove white space from the end of the StringBuffer */
static void fts3SnippetTrimWhiteSpace(StringBuffer *p){
  if( p->z ){
    while( p->nUsed && fts3snippetIsspace(p->z[p->nUsed-1]) ){
      p->nUsed--;
    }
    p->z[p->nUsed] = 0;
  }
}

/* 
** Release all memory associated with the Snippet structure passed as
** an argument.
*/
static void fts3SnippetFree(Snippet *p){
  if( p ){
    sqlite3_free(p->aMatch);
    sqlite3_free(p->zOffset);
    sqlite3_free(p->zSnippet);
    sqlite3_free(p);
  }
}

/*
** Append a single entry to the p->aMatch[] log.
*/
static int snippetAppendMatch(
  Snippet *p,               /* Append the entry to this snippet */
  int iCol, int iTerm,      /* The column and query term */
  int iToken,               /* Matching token in document */
  int iStart, int nByte     /* Offset and size of the match */
){
  int i;
  struct snippetMatch *pMatch;
  if( p->nMatch+1>=p->nAlloc ){
    struct snippetMatch *pNew;
    p->nAlloc = p->nAlloc*2 + 10;
    pNew = sqlite3_realloc(p->aMatch, p->nAlloc*sizeof(p->aMatch[0]) );
    if( pNew==0 ){
      p->aMatch = 0;
      p->nMatch = 0;
      p->nAlloc = 0;
      return SQLITE_NOMEM;
    }
    p->aMatch = pNew;
  }
  i = p->nMatch++;
  pMatch = &p->aMatch[i];
  pMatch->iCol = (short)iCol;
  pMatch->iTerm = (short)iTerm;
  pMatch->iToken = iToken;
  pMatch->iStart = iStart;
  pMatch->nByte = (short)nByte;
  return SQLITE_OK;
}

/*
** Sizing information for the circular buffer used in snippetOffsetsOfColumn()
*/
#define FTS3_ROTOR_SZ   (32)
#define FTS3_ROTOR_MASK (FTS3_ROTOR_SZ-1)

/*
** Function to iterate through the tokens of a compiled expression.
**
** Except, skip all tokens on the right-hand side of a NOT operator.
** This function is used to find tokens as part of snippet and offset
** generation and we do nt want snippets and offsets to report matches
** for tokens on the RHS of a NOT.
*/
static int fts3NextExprToken(Fts3Expr **ppExpr, int *piToken){
  Fts3Expr *p = *ppExpr;
  int iToken = *piToken;
  if( iToken<0 ){
    /* In this case the expression p is the root of an expression tree.
    ** Move to the first token in the expression tree.
    */
    while( p->pLeft ){
      p = p->pLeft;
    }
    iToken = 0;
  }else{
    assert(p && p->eType==FTSQUERY_PHRASE );
    if( iToken<(p->pPhrase->nToken-1) ){
      iToken++;
    }else{
      iToken = 0;
      while( p->pParent && p->pParent->pLeft!=p ){
        assert( p->pParent->pRight==p );
        p = p->pParent;
      }
      p = p->pParent;
      if( p ){
        assert( p->pRight!=0 );
        p = p->pRight;
        while( p->pLeft ){
          p = p->pLeft;
        }
      }
    }
  }

  *ppExpr = p;
  *piToken = iToken;
  return p?1:0;
}

/*
** Return TRUE if the expression node pExpr is located beneath the
** RHS of a NOT operator.
*/
static int fts3ExprBeneathNot(Fts3Expr *p){
  Fts3Expr *pParent;
  while( p ){
    pParent = p->pParent;
    if( pParent && pParent->eType==FTSQUERY_NOT && pParent->pRight==p ){
      return 1;
    }
    p = pParent;
  }
  return 0;
}

/*
** Add entries to pSnippet->aMatch[] for every match that occurs against
** document zDoc[0..nDoc-1] which is stored in column iColumn.
*/
static int snippetOffsetsOfColumn(
  Fts3Cursor *pCur,         /* The fulltest search cursor */
  Snippet *pSnippet,             /* The Snippet object to be filled in */
  int iColumn,                   /* Index of fulltext table column */
  const char *zDoc,              /* Text of the fulltext table column */
  int nDoc                       /* Length of zDoc in bytes */
){
  const sqlite3_tokenizer_module *pTModule;  /* The tokenizer module */
  sqlite3_tokenizer *pTokenizer;             /* The specific tokenizer */
  sqlite3_tokenizer_cursor *pTCursor;        /* Tokenizer cursor */
  Fts3Table *pVtab;                /* The full text index */
  int nColumn;                         /* Number of columns in the index */
  int i, j;                            /* Loop counters */
  int rc;                              /* Return code */
  unsigned int match, prevMatch;       /* Phrase search bitmasks */
  const char *zToken;                  /* Next token from the tokenizer */
  int nToken;                          /* Size of zToken */
  int iBegin, iEnd, iPos;              /* Offsets of beginning and end */

  /* The following variables keep a circular buffer of the last
  ** few tokens */
  unsigned int iRotor = 0;             /* Index of current token */
  int iRotorBegin[FTS3_ROTOR_SZ];      /* Beginning offset of token */
  int iRotorLen[FTS3_ROTOR_SZ];        /* Length of token */

  pVtab =  (Fts3Table *)pCur->base.pVtab;
  nColumn = pVtab->nColumn;
  pTokenizer = pVtab->pTokenizer;
  pTModule = pTokenizer->pModule;
  rc = pTModule->xOpen(pTokenizer, zDoc, nDoc, &pTCursor);
  if( rc ) return rc;
  pTCursor->pTokenizer = pTokenizer;

  prevMatch = 0;
  while( (rc = pTModule->xNext(pTCursor, &zToken, &nToken,
                               &iBegin, &iEnd, &iPos))==SQLITE_OK ){
    Fts3Expr *pIter = pCur->pExpr;
    int iIter = -1;
    iRotorBegin[iRotor&FTS3_ROTOR_MASK] = iBegin;
    iRotorLen[iRotor&FTS3_ROTOR_MASK] = iEnd-iBegin;
    match = 0;
    for(i=0; i<(FTS3_ROTOR_SZ-1) && fts3NextExprToken(&pIter, &iIter); i++){
      int nPhrase;                    /* Number of tokens in current phrase */
      struct PhraseToken *pToken;     /* Current token */
      int iCol;                       /* Column index */

      if( fts3ExprBeneathNot(pIter) ) continue;
      nPhrase = pIter->pPhrase->nToken;
      pToken = &pIter->pPhrase->aToken[iIter];
      iCol = pIter->pPhrase->iColumn;
      if( iCol>=0 && iCol<nColumn && iCol!=iColumn ) continue;
      if( pToken->n>nToken ) continue;
      if( !pToken->isPrefix && pToken->n<nToken ) continue;
      assert( pToken->n<=nToken );
      if( memcmp(pToken->z, zToken, pToken->n) ) continue;
      if( iIter>0 && (prevMatch & (1<<i))==0 ) continue;
      match |= 1<<i;
      if( i==(FTS3_ROTOR_SZ-2) || nPhrase==iIter+1 ){
        for(j=nPhrase-1; j>=0; j--){
          int k = (iRotor-j) & FTS3_ROTOR_MASK;
          rc = snippetAppendMatch(pSnippet, iColumn, i-j, iPos-j,
                                  iRotorBegin[k], iRotorLen[k]);
          if( rc ) goto end_offsets_of_column;
        }
      }
    }
    prevMatch = match<<1;
    iRotor++;
  }
end_offsets_of_column:
  pTModule->xClose(pTCursor);  
  return rc==SQLITE_DONE ? SQLITE_OK : rc;
}

/*
** Remove entries from the pSnippet structure to account for the NEAR
** operator. When this is called, pSnippet contains the list of token 
** offsets produced by treating all NEAR operators as AND operators.
** This function removes any entries that should not be present after
** accounting for the NEAR restriction. For example, if the queried
** document is:
**
**     "A B C D E A"
**
** and the query is:
** 
**     A NEAR/0 E
**
** then when this function is called the Snippet contains token offsets
** 0, 4 and 5. This function removes the "0" entry (because the first A
** is not near enough to an E).
**
** When this function is called, the value pointed to by parameter piLeft is
** the integer id of the left-most token in the expression tree headed by
** pExpr. This function increments *piLeft by the total number of tokens
** in the expression tree headed by pExpr.
**
** Return 1 if any trimming occurs.  Return 0 if no trimming is required.
*/
static int trimSnippetOffsets(
  Fts3Expr *pExpr,      /* The search expression */
  Snippet *pSnippet,    /* The set of snippet offsets to be trimmed */
  int *piLeft           /* Index of left-most token in pExpr */
){
  if( pExpr ){
    if( trimSnippetOffsets(pExpr->pLeft, pSnippet, piLeft) ){
      return 1;
    }

    switch( pExpr->eType ){
      case FTSQUERY_PHRASE:
        *piLeft += pExpr->pPhrase->nToken;
        break;
      case FTSQUERY_NEAR: {
        /* The right-hand-side of a NEAR operator is always a phrase. The
        ** left-hand-side is either a phrase or an expression tree that is 
        ** itself headed by a NEAR operator. The following initializations
        ** set local variable iLeft to the token number of the left-most
        ** token in the right-hand phrase, and iRight to the right most
        ** token in the same phrase. For example, if we had:
        **
        **     <col> MATCH '"abc def" NEAR/2 "ghi jkl"'
        **
        ** then iLeft will be set to 2 (token number of ghi) and nToken will
        ** be set to 4.
        */
        Fts3Expr *pLeft = pExpr->pLeft;
        Fts3Expr *pRight = pExpr->pRight;
        int iLeft = *piLeft;
        int nNear = pExpr->nNear;
        int nToken = pRight->pPhrase->nToken;
        int jj, ii;
        if( pLeft->eType==FTSQUERY_NEAR ){
          pLeft = pLeft->pRight;
        }
        assert( pRight->eType==FTSQUERY_PHRASE );
        assert( pLeft->eType==FTSQUERY_PHRASE );
        nToken += pLeft->pPhrase->nToken;

        for(ii=0; ii<pSnippet->nMatch; ii++){
          struct snippetMatch *p = &pSnippet->aMatch[ii];
          if( p->iTerm==iLeft ){
            int isOk = 0;
            /* Snippet ii is an occurence of query term iLeft in the document.
            ** It occurs at position (p->iToken) of the document. We now
            ** search for an instance of token (iLeft-1) somewhere in the 
            ** range (p->iToken - nNear)...(p->iToken + nNear + nToken) within 
            ** the set of snippetMatch structures. If one is found, proceed. 
            ** If one cannot be found, then remove snippets ii..(ii+N-1) 
            ** from the matching snippets, where N is the number of tokens 
            ** in phrase pRight->pPhrase.
            */
            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
              if( p2->iTerm==(iLeft-1) ){
                if( p2->iToken>=(p->iToken-nNear-1) 
                 && p2->iToken<(p->iToken+nNear+nToken) 
                ){
                  isOk = 1;
                }
              }
            }
            if( !isOk ){
              int kk;
              for(kk=0; kk<pRight->pPhrase->nToken; kk++){
                pSnippet->aMatch[kk+ii].iTerm = -2;
              }
              return 1;
            }
          }
          if( p->iTerm==(iLeft-1) ){
            int isOk = 0;
            for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
              struct snippetMatch *p2 = &pSnippet->aMatch[jj];
              if( p2->iTerm==iLeft ){
                if( p2->iToken<=(p->iToken+nNear+1) 
                 && p2->iToken>(p->iToken-nNear-nToken) 
                ){
                  isOk = 1;
                }
              }
            }
            if( !isOk ){
              int kk;
              for(kk=0; kk<pLeft->pPhrase->nToken; kk++){
                pSnippet->aMatch[ii-kk].iTerm = -2;
              }
              return 1;
            }
          }
        }
        break;
      }
    }

    if( trimSnippetOffsets(pExpr->pRight, pSnippet, piLeft) ){
      return 1;
    }
  }
  return 0;
}

/*
** Compute all offsets for the current row of the query.  
** If the offsets have already been computed, this routine is a no-op.
*/
static int snippetAllOffsets(Fts3Cursor *pCsr, Snippet **ppSnippet){
  Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;  /* The FTS3 virtual table */
  int nColumn;           /* Number of columns.  Docid does count */
  int iColumn;           /* Index of of a column */
  int i;                 /* Loop index */
  int iFirst;            /* First column to search */
  int iLast;             /* Last coumn to search */
  int iTerm = 0;
  Snippet *pSnippet;
  int rc = SQLITE_OK;

  if( pCsr->pExpr==0 ){
    return SQLITE_OK;
  }

  pSnippet = (Snippet *)sqlite3_malloc(sizeof(Snippet));
  *ppSnippet = pSnippet;
  if( !pSnippet ){
    return SQLITE_NOMEM;
  }
  memset(pSnippet, 0, sizeof(Snippet));

  nColumn = p->nColumn;
  iColumn = (pCsr->eSearch - 2);
  if( iColumn<0 || iColumn>=nColumn ){
    /* Look for matches over all columns of the full-text index */
    iFirst = 0;
    iLast = nColumn-1;
  }else{
    /* Look for matches in the iColumn-th column of the index only */
    iFirst = iColumn;
    iLast = iColumn;
  }
  for(i=iFirst; rc==SQLITE_OK && i<=iLast; i++){
    const char *zDoc;
    int nDoc;
    zDoc = (const char*)sqlite3_column_text(pCsr->pStmt, i+1);
    nDoc = sqlite3_column_bytes(pCsr->pStmt, i+1);
    if( zDoc==0 && sqlite3_column_type(pCsr->pStmt, i+1)!=SQLITE_NULL ){
      rc = SQLITE_NOMEM;
    }else{
      rc = snippetOffsetsOfColumn(pCsr, pSnippet, i, zDoc, nDoc);
    }
  }

  while( trimSnippetOffsets(pCsr->pExpr, pSnippet, &iTerm) ){
    iTerm = 0;
  }

  return rc;
}

/*
** Convert the information in the aMatch[] array of the snippet
** into the string zOffset[0..nOffset-1]. This string is used as
** the return of the SQL offsets() function.
*/
static void snippetOffsetText(Snippet *p){
  int i;
  int cnt = 0;
  StringBuffer sb;
  char zBuf[200];
  if( p->zOffset ) return;
  fts3SnippetSbInit(&sb);
  for(i=0; i<p->nMatch; i++){
    struct snippetMatch *pMatch = &p->aMatch[i];
    if( pMatch->iTerm>=0 ){
      /* If snippetMatch.iTerm is less than 0, then the match was 
      ** discarded as part of processing the NEAR operator (see the 
      ** trimSnippetOffsetsForNear() function for details). Ignore 
      ** it in this case
      */
      zBuf[0] = ' ';
      sqlite3_snprintf(sizeof(zBuf)-1, &zBuf[cnt>0], "%d %d %d %d",
          pMatch->iCol, pMatch->iTerm, pMatch->iStart, pMatch->nByte);
      fts3SnippetAppend(&sb, zBuf, -1);
      cnt++;
    }
  }
  p->zOffset = sb.z;
  p->nOffset = sb.z ? sb.nUsed : 0;
}

/*
** zDoc[0..nDoc-1] is phrase of text.  aMatch[0..nMatch-1] are a set
** of matching words some of which might be in zDoc.  zDoc is column
** number iCol.
**
** iBreak is suggested spot in zDoc where we could begin or end an
** excerpt.  Return a value similar to iBreak but possibly adjusted
** to be a little left or right so that the break point is better.
*/
static int wordBoundary(
  int iBreak,                   /* The suggested break point */
  const char *zDoc,             /* Document text */
  int nDoc,                     /* Number of bytes in zDoc[] */
  struct snippetMatch *aMatch,  /* Matching words */
  int nMatch,                   /* Number of entries in aMatch[] */
  int iCol                      /* The column number for zDoc[] */
){
  int i;
  if( iBreak<=10 ){
    return 0;
  }
  if( iBreak>=nDoc-10 ){
    return nDoc;
  }
  for(i=0; ALWAYS(i<nMatch) && aMatch[i].iCol<iCol; i++){}
  while( i<nMatch && aMatch[i].iStart+aMatch[i].nByte<iBreak ){ i++; }
  if( i<nMatch ){
    if( aMatch[i].iStart<iBreak+10 ){
      return aMatch[i].iStart;
    }
    if( i>0 && aMatch[i-1].iStart+aMatch[i-1].nByte>=iBreak ){
      return aMatch[i-1].iStart;
    }
  }
  for(i=1; i<=10; i++){
    if( fts3snippetIsspace(zDoc[iBreak-i]) ){
      return iBreak - i + 1;
    }
    if( fts3snippetIsspace(zDoc[iBreak+i]) ){
      return iBreak + i + 1;
    }
  }
  return iBreak;
}



/*
** Allowed values for Snippet.aMatch[].snStatus
*/
#define SNIPPET_IGNORE  0   /* It is ok to omit this match from the snippet */
#define SNIPPET_DESIRED 1   /* We want to include this match in the snippet */

/*
** Generate the text of a snippet.
*/
static void snippetText(
  Fts3Cursor *pCursor,   /* The cursor we need the snippet for */
  Snippet *pSnippet,
  const char *zStartMark,     /* Markup to appear before each match */
  const char *zEndMark,       /* Markup to appear after each match */
  const char *zEllipsis       /* Ellipsis mark */
){
  int i, j;
  struct snippetMatch *aMatch;
  int nMatch;
  int nDesired;
  StringBuffer sb;
  int tailCol;
  int tailOffset;
  int iCol;
  int nDoc;
  const char *zDoc;
  int iStart, iEnd;
  int tailEllipsis = 0;
  int iMatch;
  

  sqlite3_free(pSnippet->zSnippet);
  pSnippet->zSnippet = 0;
  aMatch = pSnippet->aMatch;
  nMatch = pSnippet->nMatch;
  fts3SnippetSbInit(&sb);

  for(i=0; i<nMatch; i++){
    aMatch[i].snStatus = SNIPPET_IGNORE;
  }
  nDesired = 0;
  for(i=0; i<FTS3_ROTOR_SZ; i++){
    for(j=0; j<nMatch; j++){
      if( aMatch[j].iTerm==i ){
        aMatch[j].snStatus = SNIPPET_DESIRED;
        nDesired++;
        break;
      }
    }
  }

  iMatch = 0;
  tailCol = -1;
  tailOffset = 0;
  for(i=0; i<nMatch && nDesired>0; i++){
    if( aMatch[i].snStatus!=SNIPPET_DESIRED ) continue;
    nDesired--;
    iCol = aMatch[i].iCol;
    zDoc = (const char*)sqlite3_column_text(pCursor->pStmt, iCol+1);
    nDoc = sqlite3_column_bytes(pCursor->pStmt, iCol+1);
    iStart = aMatch[i].iStart - 40;
    iStart = wordBoundary(iStart, zDoc, nDoc, aMatch, nMatch, iCol);
    if( iStart<=10 ){
      iStart = 0;
    }
    if( iCol==tailCol && iStart<=tailOffset+20 ){
      iStart = tailOffset;
    }
    if( (iCol!=tailCol && tailCol>=0) || iStart!=tailOffset ){
      fts3SnippetTrimWhiteSpace(&sb);
      fts3SnippetAppendWhiteSpace(&sb);
      fts3SnippetAppend(&sb, zEllipsis, -1);
      fts3SnippetAppendWhiteSpace(&sb);
    }
    iEnd = aMatch[i].iStart + aMatch[i].nByte + 40;
    iEnd = wordBoundary(iEnd, zDoc, nDoc, aMatch, nMatch, iCol);
    if( iEnd>=nDoc-10 ){
      iEnd = nDoc;
      tailEllipsis = 0;
    }else{
      tailEllipsis = 1;
    }
    while( iMatch<nMatch && aMatch[iMatch].iCol<iCol ){ iMatch++; }
    while( iStart<iEnd ){
      while( iMatch<nMatch && aMatch[iMatch].iStart<iStart
             && aMatch[iMatch].iCol<=iCol ){
        iMatch++;
      }
      if( iMatch<nMatch && aMatch[iMatch].iStart<iEnd
             && aMatch[iMatch].iCol==iCol ){
        fts3SnippetAppend(&sb, &zDoc[iStart], aMatch[iMatch].iStart - iStart);
        iStart = aMatch[iMatch].iStart;
        fts3SnippetAppend(&sb, zStartMark, -1);
        fts3SnippetAppend(&sb, &zDoc[iStart], aMatch[iMatch].nByte);
        fts3SnippetAppend(&sb, zEndMark, -1);
        iStart += aMatch[iMatch].nByte;
        for(j=iMatch+1; j<nMatch; j++){
          if( aMatch[j].iTerm==aMatch[iMatch].iTerm
              && aMatch[j].snStatus==SNIPPET_DESIRED ){
            nDesired--;
            aMatch[j].snStatus = SNIPPET_IGNORE;
          }
        }
      }else{
        fts3SnippetAppend(&sb, &zDoc[iStart], iEnd - iStart);
        iStart = iEnd;
      }
    }
    tailCol = iCol;
    tailOffset = iEnd;
  }
  fts3SnippetTrimWhiteSpace(&sb);
  if( tailEllipsis ){
    fts3SnippetAppendWhiteSpace(&sb);
    fts3SnippetAppend(&sb, zEllipsis, -1);
  }
  pSnippet->zSnippet = sb.z;
  pSnippet->nSnippet = sb.z ? sb.nUsed : 0;
}

void sqlite3Fts3Offsets(
  sqlite3_context *pCtx,          /* SQLite function call context */
  Fts3Cursor *pCsr                /* Cursor object */
){
  Snippet *p;                     /* Snippet structure */
  int rc = snippetAllOffsets(pCsr, &p);
  if( rc==SQLITE_OK ){
    snippetOffsetText(p);
    if( p->zOffset ){
      sqlite3_result_text(pCtx, p->zOffset, p->nOffset, SQLITE_TRANSIENT);
    }else{
      sqlite3_result_error_nomem(pCtx);
    }
  }else{
    sqlite3_result_error_nomem(pCtx);
  }
  fts3SnippetFree(p);
}

void sqlite3Fts3Snippet(
  sqlite3_context *pCtx,          /* SQLite function call context */
  Fts3Cursor *pCsr,               /* Cursor object */
  const char *zStart,             /* Snippet start text - "<b>" */
  const char *zEnd,               /* Snippet end text - "</b>" */
  const char *zEllipsis           /* Snippet ellipsis text - "<b>...</b>" */
){
  Snippet *p;                     /* Snippet structure */
  int rc = snippetAllOffsets(pCsr, &p);
  if( rc==SQLITE_OK ){
    snippetText(pCsr, p, zStart, zEnd, zEllipsis);
    if( p->zSnippet ){
      sqlite3_result_text(pCtx, p->zSnippet, p->nSnippet, SQLITE_TRANSIENT);
    }else{
      sqlite3_result_error_nomem(pCtx);
    }
  }else{
    sqlite3_result_error_nomem(pCtx);
  }
  fts3SnippetFree(p);
}

/*************************************************************************
** Below this point is the alternative, experimental snippet() implementation.
*/

#define SNIPPET_BUFFER_CHUNK  64
#define SNIPPET_BUFFER_SIZE   SNIPPET_BUFFER_CHUNK*4
#define SNIPPET_BUFFER_MASK   (SNIPPET_BUFFER_SIZE-1)

static void fts3GetDeltaPosition(char **pp, int *piPos){
  int iVal;
  *pp += sqlite3Fts3GetVarint32(*pp, &iVal);
................................................................................
  return rc;
}

typedef struct LoadDoclistCtx LoadDoclistCtx;
struct LoadDoclistCtx {
  Fts3Table *pTab;                /* FTS3 Table */
  int nPhrase;                    /* Number of phrases so far */

};
































static int fts3ExprLoadDoclistsCb(Fts3Expr *pExpr, void *ctx){
  int rc = SQLITE_OK;
  LoadDoclistCtx *p = (LoadDoclistCtx *)ctx;

  p->nPhrase++;


  if( pExpr->isLoaded==0 ){
    rc = sqlite3Fts3ExprLoadDoclist(p->pTab, pExpr);
    pExpr->isLoaded = 1;
    if( rc==SQLITE_OK && pExpr->aDoclist ){
      pExpr->pCurrent = pExpr->aDoclist;
      pExpr->pCurrent += sqlite3Fts3GetVarint(pExpr->pCurrent,&pExpr->iCurrent);
    }
  }

  return rc;
}










static int fts3ExprLoadDoclists(Fts3Cursor *pCsr, int *pnPhrase){




  int rc;
  LoadDoclistCtx sCtx = {0, 0};
  sCtx.pTab = (Fts3Table *)pCsr->base.pVtab;
  rc = fts3ExprIterate(pCsr->pExpr, fts3ExprLoadDoclistsCb, (void *)&sCtx);



  *pnPhrase = sCtx.nPhrase;

  return rc;
}

/*
** Each call to this function populates a chunk of a snippet-buffer 
** SNIPPET_BUFFER_CHUNK bytes in size.
**
................................................................................

  memset(&aBuffer[iPos&SNIPPET_BUFFER_MASK], 0, SNIPPET_BUFFER_CHUNK);

  for(i=0; i<nList; i++){
    int iPrev = aiPrev[i];
    char *pList = apList[i];

    if( !pList ){
      nFin++;
      continue;
    }

    while( iPrev<(iPos+SNIPPET_BUFFER_CHUNK) ){
      if( iPrev>=iPos ){
        aBuffer[iPrev&SNIPPET_BUFFER_MASK] = (u8)(i+1);
      }
      if( 0==((*pList)&0xFE) ){
        nFin++;

        break;
      }

      fts3GetDeltaPosition(&pList, &iPrev); 

    }

    aiPrev[i] = iPrev;
    apList[i] = pList;
  }

  return (nFin==nList);
................................................................................
  int *anCnt, 
  u8 *aBuffer,
  int *anToken,
  u64 *pHlmask
){
  int iSub =  (iIdx-1)&SNIPPET_BUFFER_MASK;
  int iAdd =  (iIdx+nSnippet-1)&SNIPPET_BUFFER_MASK;
  int iSub2 = (iIdx+(nSnippet/3)-1)&SNIPPET_BUFFER_MASK;
  int iAdd2 = (iIdx+(nSnippet*2/3)-1)&SNIPPET_BUFFER_MASK;

  u64 h = *pHlmask;

  anCnt[ aBuffer[iSub]  ]--;
  anCnt[ aBuffer[iSub2] ]--;
  anCnt[ aBuffer[iAdd]  ]++;
  anCnt[ aBuffer[iAdd2] ]++;

  h = h >> 1;
  if( aBuffer[iAdd] ){
    int j;
    for(j=anToken[aBuffer[iAdd]-1]; j>=1; j--){
      h |= (u64)1 << (nSnippet-j);
    }
  }
  *pHlmask = h;
}

static int fts3SnippetScore(int n, int *anCnt){
  int j;
  int iScore = 0;
  for(j=1; j<=n; j++){
    int nCnt = anCnt[j];
    iScore += nCnt + (nCnt ? 1000 : 0);


  }

  return iScore;
}




















static int fts3BestSnippet(
  int nSnippet,                   /* Desired snippet length */
  Fts3Cursor *pCsr,               /* Cursor to create snippet for */
  int iCol,                       /* Index of column to create snippet from */
  int *piPos,                     /* OUT: Starting token for best snippet */
  u64 *pHlmask                    /* OUT: Highlight mask for best snippet */


){
  int rc;                         /* Return Code */
  u8 aBuffer[SNIPPET_BUFFER_SIZE];/* Circular snippet buffer */
  int *aiPrev;                    /* Used by fts3LoadSnippetBuffer() */
  int *anToken;                   /* Number of tokens in each phrase */
  char **apList;                  /* Array of position lists */
  int *anCnt;                     /* Running totals of phrase occurences */
  int nList;


  int i;

  u64 hlmask = 0;                 /* Current mask of highlighted terms */
  u64 besthlmask = 0;             /* Mask of highlighted terms for iBestPos */

  int iBestPos = 0;               /* Starting position of 'best' snippet */
  int iBestScore = 0;             /* Score of best snippet higher->better */

  SnippetCtx sCtx;

  /* Iterate through the phrases in the expression to count them. The same
  ** callback makes sure the doclists are loaded for each phrase.
  */
  rc = fts3ExprLoadDoclists(pCsr, &nList);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  /* Now that it is known how many phrases there are, allocate and zero
  ** the required arrays using malloc().
  */
  apList = sqlite3_malloc(
      sizeof(u8*)*nList +         /* apList */
      sizeof(int)*(nList) +       /* anToken */
      sizeof(int)*nList +         /* aiPrev */
      sizeof(int)*(nList+1)       /* anCnt */
  );

  if( !apList ){
    return SQLITE_NOMEM;
  }
  memset(apList, 0, sizeof(u8*)*nList+sizeof(int)*nList+sizeof(int)*nList);
  anToken = (int *)&apList[nList];
  aiPrev = &anToken[nList];
  anCnt = &aiPrev[nList];

  /* Initialize the contents of the aiPrev and aiList arrays. */
  sCtx.pCsr = pCsr;
  sCtx.iCol = iCol;
  sCtx.apList = apList;
  sCtx.aiPrev = aiPrev;
  sCtx.anToken = anToken;
  sCtx.iPhrase = 0;
  (void)fts3ExprIterate(pCsr->pExpr, fts3SnippetFindPositions, (void *)&sCtx);







  /* Load the first two chunks of data into the buffer. */
  memset(aBuffer, 0, SNIPPET_BUFFER_SIZE);
  fts3LoadSnippetBuffer(0, aBuffer, nList, apList, aiPrev);
  fts3LoadSnippetBuffer(SNIPPET_BUFFER_CHUNK, aBuffer, nList, apList, aiPrev);

  /* Set the initial contents of the highlight-mask and anCnt[] array. */
  for(i=1-nSnippet; i<=0; i++){
    fts3SnippetCnt(i, nSnippet, anCnt, aBuffer, anToken, &hlmask);
  }
  iBestScore = fts3SnippetScore(nList, anCnt);
  besthlmask = hlmask;
  iBestPos = 0;


  for(i=1; 1; i++){
    int iScore;

    if( 0==(i&(SNIPPET_BUFFER_CHUNK-1)) ){
      int iLoad = i + SNIPPET_BUFFER_CHUNK;
      if( fts3LoadSnippetBuffer(iLoad, aBuffer, nList, apList, aiPrev) ) break;


    }

    /* Figure out how highly a snippet starting at token offset i scores
    ** according to fts3SnippetScore(). If it is higher than any previously
    ** considered position, save the current position, score and hlmask as 
    ** the best snippet candidate found so far.
    */
    fts3SnippetCnt(i, nSnippet, anCnt, aBuffer, anToken, &hlmask);
    iScore = fts3SnippetScore(nList, anCnt);
    if( iScore>iBestScore ){
      iBestPos = i;
      iBestScore = iScore;
      besthlmask = hlmask;

    }
  }

  sqlite3_free(apList);

  *piPos = iBestPos;
  *pHlmask = besthlmask;



  return SQLITE_OK;
}

typedef struct StrBuffer StrBuffer;
struct StrBuffer {
  char *z;
  int n;
................................................................................

static int fts3StringAppend(
  StrBuffer *pStr, 
  const char *zAppend, 
  int nAppend
){
  if( nAppend<0 ){
    nAppend = (int)strlen(zAppend);
  }

  if( pStr->n+nAppend+1>=pStr->nAlloc ){
    int nAlloc = pStr->nAlloc+nAppend+100;
    char *zNew = sqlite3_realloc(pStr->z, nAlloc);
    if( !zNew ){
      return SQLITE_NOMEM;
................................................................................

  memcpy(&pStr->z[pStr->n], zAppend, nAppend);
  pStr->n += nAppend;
  pStr->z[pStr->n] = '\0';

  return SQLITE_OK;
}
















































static int fts3SnippetText(
  Fts3Cursor *pCsr,               /* FTS3 Cursor */
  const char *zDoc,               /* Document to extract snippet from */
  int nDoc,                       /* Size of zDoc in bytes */

  int nSnippet,                   /* Number of tokens in extracted snippet */
  int iPos,                       /* Index of first document token in snippet */
  u64 hlmask,                     /* Bitmask of terms to highlight in snippet */
  const char *zOpen,              /* String inserted before highlighted term */
  const char *zClose,             /* String inserted after highlighted term */
  const char *zEllipsis,
  char **pzSnippet                /* OUT: Snippet text */
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int rc;                         /* Return code */


  int iCurrent = 0;
  int iStart = 0;
  int iEnd;





  sqlite3_tokenizer_module *pMod; /* Tokenizer module methods object */
  sqlite3_tokenizer_cursor *pC;   /* Tokenizer cursor open on zDoc/nDoc */
  const char *ZDUMMY;             /* Dummy arguments used with tokenizer */
  int DUMMY1, DUMMY2, DUMMY3;     /* Dummy arguments used with tokenizer */

  StrBuffer res = {0, 0, 0};   /* Result string */








  /* Open a token cursor on the document. Read all tokens up to and 
  ** including token iPos (the first token of the snippet). Set variable
  ** iStart to the byte offset in zDoc of the start of token iPos.
  */
  pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
  rc = pMod->xOpen(pTab->pTokenizer, zDoc, nDoc, &pC);
  while( rc==SQLITE_OK && iCurrent<iPos ){
    rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &iStart, &DUMMY2, &iCurrent);
  }
  iEnd = iStart;

  if( rc==SQLITE_OK && iStart>0 ){
    rc = fts3StringAppend(&res, zEllipsis, -1);
  }

  while( rc==SQLITE_OK ){
    int iBegin;
    int iFin;
    rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &iBegin, &iFin, &iCurrent);

    if( rc==SQLITE_OK ){











      if( iCurrent>=(iPos+nSnippet) ){
        rc = SQLITE_DONE;
      }else{
        iEnd = iFin;
        if( hlmask & ((u64)1 << (iCurrent-iPos)) ){
          if( fts3StringAppend(&res, &zDoc[iStart], iBegin-iStart)
           || fts3StringAppend(&res, zOpen, -1)
           || fts3StringAppend(&res, &zDoc[iBegin], iEnd-iBegin)
           || fts3StringAppend(&res, zClose, -1)
          ){
            rc = SQLITE_NOMEM;
          }
          iStart = iEnd;
        }
      }
    }
  }
  assert( rc!=SQLITE_OK );
  if( rc==SQLITE_DONE ){
    rc = fts3StringAppend(&res, &zDoc[iStart], iEnd-iStart);
    if( rc==SQLITE_OK ){
      rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &DUMMY2, &DUMMY3, &iCurrent);
      if( rc==SQLITE_OK ){
        rc = fts3StringAppend(&res, zEllipsis, -1);
      }else if( rc==SQLITE_DONE ){
        rc = fts3StringAppend(&res, &zDoc[iEnd], -1);
      }
    }
  }

  pMod->xClose(pC);
  if( rc!=SQLITE_OK ){
    sqlite3_free(res.z);
  }else{
    *pzSnippet = res.z;
  }
  return rc;
}


/*
** An instance of this structure is used to collect the 'global' part of
** the matchinfo statistics. The 'global' part consists of the following:
................................................................................
    int rc;
    int nPhrase;
    int nMatchinfo;

    g.pTab = pTab;
    g.nCol = pTab->nColumn;
    g.iPhrase = 0;
    rc = fts3ExprLoadDoclists(pCsr, &nPhrase);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    nMatchinfo = 2 + 2*g.nCol*nPhrase;

    g.iPhrase = 0;
................................................................................
    (void)fts3ExprIterate(pCsr->pExpr, fts3ExprLocalMatchinfoCb, (void *)&g);
    pCsr->isMatchinfoOk = 0;
  }

  return SQLITE_OK;
}

void sqlite3Fts3Snippet2(
  sqlite3_context *pCtx,          /* SQLite function call context */
  Fts3Cursor *pCsr,               /* Cursor object */
  const char *zStart,             /* Snippet start text - "<b>" */
  const char *zEnd,               /* Snippet end text - "</b>" */
  const char *zEllipsis,          /* Snippet ellipsis text - "<b>...</b>" */
  int iCol,                       /* Extract snippet from this column */
  int nToken                      /* Approximate number of tokens in snippet */
){


  int rc;



































  int iPos = 0;
  u64 hlmask = 0;
































































































  char *z = 0;



























  int nDoc;

  const char *zDoc;


  rc = fts3BestSnippet(nToken, pCsr, iCol, &iPos, &hlmask);






  nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol+1);

  zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol+1);
































  if( rc==SQLITE_OK ){
    rc = fts3SnippetText(
        pCsr, zDoc, nDoc, nToken, iPos, hlmask, zStart, zEnd, zEllipsis, &z);





  }













  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pCtx, rc);

  }else{
    sqlite3_result_text(pCtx, z, -1, sqlite3_free);
  }

}

void sqlite3Fts3Matchinfo(sqlite3_context *pContext, Fts3Cursor *pCsr){
  int rc = fts3GetMatchinfo(pCsr);
  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pContext, rc);
  }else{
    int n = sizeof(u32)*(2+pCsr->aMatchinfo[0]*pCsr->aMatchinfo[1]*2);
    sqlite3_result_blob(pContext, pCsr->aMatchinfo, n, SQLITE_TRANSIENT);
  }
}

#endif







<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<







 







>


>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|


>

>
>



|
|
<


>



>
>
>
>
>
>
>
>
>
|
>
>
>
>

|

|
>
>
>
|
>







 







|





|
|
<

<
>

<
>
|
>







 







<
<




<

<











|




|
>
>
|
>


>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>





|
|
>
>







|
<
>
|
<


>


>





|







<
|


|
<
>



|












>
>
>
>
>
>










|


>

|




|
>
>








|




>




>
|
|
>
>
>







 







|







 








>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>


<
<
>

<
<



|



>
>
|
|
<
>
>
>
>





|
|
>
>
>
>
>
>
>







|
|

|
<
<
<
<







>
>
>
>
>
>
>
>
>
>
>





|
|
|
|










|


|
|
|
|





<
<
<
<
<







 







|







 







|








>
>
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
<
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>
|
>

<
>
>
>
>
>

<
>
|
>
>
>
>

>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
<
<
>
>
>
>
>
|
>
>
>
>
>
>
>
>
>
>
>
>
>

|
>

|

>













14
15
16
17
18
19
20













































































































































































































































































































































































































































































































































































































































































































































21
22
23
24
25
26
27
..
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111

112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
...
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177

178

179
180

181
182
183
184
185
186
187
188
189
190
...
223
224
225
226
227
228
229


230
231
232
233

234

235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293

294
295

296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314

315
316
317
318

319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
...
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
...
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473


474
475


476
477
478
479
480
481
482
483
484
485
486

487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515




516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564





565
566
567
568
569
570
571
...
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
...
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776

777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905

906
907
908
909
910
911

912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946


947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

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














































































































































































































































































































































































































































































































































































































































































































































#define SNIPPET_BUFFER_CHUNK  64
#define SNIPPET_BUFFER_SIZE   SNIPPET_BUFFER_CHUNK*4
#define SNIPPET_BUFFER_MASK   (SNIPPET_BUFFER_SIZE-1)

static void fts3GetDeltaPosition(char **pp, int *piPos){
  int iVal;
  *pp += sqlite3Fts3GetVarint32(*pp, &iVal);
................................................................................
  return rc;
}

typedef struct LoadDoclistCtx LoadDoclistCtx;
struct LoadDoclistCtx {
  Fts3Table *pTab;                /* FTS3 Table */
  int nPhrase;                    /* Number of phrases so far */
  int nToken;                     /* Number of tokens so far */
};

static int fts3ExprNearTrim(Fts3Expr *pExpr){
  int rc = SQLITE_OK;
  Fts3Expr *pParent = pExpr->pParent;

  assert( pExpr->eType==FTSQUERY_PHRASE );
  while( rc==SQLITE_OK
   && pExpr->aDoclist && pParent 
   && pParent->eType==FTSQUERY_NEAR 
   && pParent->pRight==pExpr 
  ){
    /* This expression (pExpr) is the right-hand-side of a NEAR operator. 
    ** Find the expression to the left of the same operator.
    */
    int nNear = pParent->nNear;
    Fts3Expr *pLeft = pParent->pLeft;

    if( pLeft->eType!=FTSQUERY_PHRASE ){
      assert( pLeft->eType==FTSQUERY_NEAR );
      assert( pLeft->pRight->eType==FTSQUERY_PHRASE );
      pLeft = pLeft->pRight;
    }

    rc = sqlite3Fts3ExprNearTrim(pLeft, pExpr, nNear);

    pExpr = pLeft;
    pParent = pExpr->pParent;
  }

  return rc;
}

static int fts3ExprLoadDoclistsCb1(Fts3Expr *pExpr, void *ctx){
  int rc = SQLITE_OK;
  LoadDoclistCtx *p = (LoadDoclistCtx *)ctx;

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

  if( pExpr->isLoaded==0 ){
    rc = sqlite3Fts3ExprLoadDoclist(p->pTab, pExpr);
    pExpr->isLoaded = 1;
    if( rc==SQLITE_OK ){
      fts3ExprNearTrim(pExpr);

    }
  }

  return rc;
}

static int fts3ExprLoadDoclistsCb2(Fts3Expr *pExpr, void *ctx){
  if( pExpr->aDoclist ){
    pExpr->pCurrent = pExpr->aDoclist;
    pExpr->iCurrent = 0;
    pExpr->pCurrent += sqlite3Fts3GetVarint(pExpr->pCurrent, &pExpr->iCurrent);
  }
  return SQLITE_OK;
}

static int fts3ExprLoadDoclists(
  Fts3Cursor *pCsr, 
  int *pnPhrase,                  /* OUT: Number of phrases in query */
  int *pnToken                    /* OUT: Number of tokens in query */
){
  int rc;
  LoadDoclistCtx sCtx = {0, 0, 0};
  sCtx.pTab = (Fts3Table *)pCsr->base.pVtab;
  rc = fts3ExprIterate(pCsr->pExpr, fts3ExprLoadDoclistsCb1, (void *)&sCtx);
  if( rc==SQLITE_OK ){
    (void)fts3ExprIterate(pCsr->pExpr, fts3ExprLoadDoclistsCb2, 0);
  }
  if( pnPhrase ) *pnPhrase = sCtx.nPhrase;
  if( pnToken ) *pnToken = sCtx.nToken;
  return rc;
}

/*
** Each call to this function populates a chunk of a snippet-buffer 
** SNIPPET_BUFFER_CHUNK bytes in size.
**
................................................................................

  memset(&aBuffer[iPos&SNIPPET_BUFFER_MASK], 0, SNIPPET_BUFFER_CHUNK);

  for(i=0; i<nList; i++){
    int iPrev = aiPrev[i];
    char *pList = apList[i];

    if( iPrev<0 || !pList ){
      nFin++;
      continue;
    }

    while( iPrev<(iPos+SNIPPET_BUFFER_CHUNK) ){
      assert( iPrev>=iPos );
      aBuffer[iPrev&SNIPPET_BUFFER_MASK] = i+1;

      if( 0==((*pList)&0xFE) ){

        iPrev = -1;
        break;

      }else{
        fts3GetDeltaPosition(&pList, &iPrev); 
      }
    }

    aiPrev[i] = iPrev;
    apList[i] = pList;
  }

  return (nFin==nList);
................................................................................
  int *anCnt, 
  u8 *aBuffer,
  int *anToken,
  u64 *pHlmask
){
  int iSub =  (iIdx-1)&SNIPPET_BUFFER_MASK;
  int iAdd =  (iIdx+nSnippet-1)&SNIPPET_BUFFER_MASK;



  u64 h = *pHlmask;

  anCnt[ aBuffer[iSub]  ]--;

  anCnt[ aBuffer[iAdd]  ]++;


  h = h >> 1;
  if( aBuffer[iAdd] ){
    int j;
    for(j=anToken[aBuffer[iAdd]-1]; j>=1; j--){
      h |= (u64)1 << (nSnippet-j);
    }
  }
  *pHlmask = h;
}

static int fts3SnippetScore(int n, int *anCnt, u64 covmask){
  int j;
  int iScore = 0;
  for(j=1; j<=n; j++){
    int nCnt = anCnt[j];
    iScore += nCnt;
    if( nCnt && 0==(covmask & ((u64)1 << (j-1))) ){
      iScore += 1000;
    }
  }
  return iScore;
}

static u64 fts3SnippetMask(int n, int *anCnt){
  int j;
  u64 mask = 0;

  if( n>64 ) n = 64;
  for(j=1; j<=n; j++){
    if( anCnt[j] ) mask |= ((u64)1)<<(j-1);
  }
  return mask;
}

typedef struct SnippetFragment SnippetFragment;
struct SnippetFragment {
  int iCol;                       /* Column snippet is extracted from */
  int iPos;                       /* Index of first token in snippet */
  u64 covered;                    /* Mask of query phrases covered */
  u64 hlmask;                     /* Mask of snippet terms to highlight */
};

static int fts3BestSnippet(
  int nSnippet,                   /* Desired snippet length */
  Fts3Cursor *pCsr,               /* Cursor to create snippet for */
  int iCol,                       /* Index of column to create snippet from */
  u64 mCovered,                   /* Mask of phrases already covered */
  u64 *pmSeen,                    /* IN/OUT: Mask of phrases seen */
  SnippetFragment *pFragment,     /* OUT: Best snippet found */
  int *piScore                    /* OUT: Score of snippet pFragment */
){
  int rc;                         /* Return Code */
  u8 aBuffer[SNIPPET_BUFFER_SIZE];/* Circular snippet buffer */
  int *aiPrev;                    /* Used by fts3LoadSnippetBuffer() */
  int *anToken;                   /* Number of tokens in each phrase */
  char **apList;                  /* Array of position lists */
  int *anCnt;                     /* Running totals of phrase occurences */
  int nList;                      /* Number of phrases in expression */

  int nByte;                      /* Bytes of dynamic space required */
  int i;                          /* Loop counter */

  u64 hlmask = 0;                 /* Current mask of highlighted terms */
  u64 besthlmask = 0;             /* Mask of highlighted terms for iBestPos */
  u64 bestcovmask = 0;            /* Mask of terms with at least one hit */
  int iBestPos = 0;               /* Starting position of 'best' snippet */
  int iBestScore = 0;             /* Score of best snippet higher->better */
  int iEnd = 0x7FFFFFFF;
  SnippetCtx sCtx;

  /* Iterate through the phrases in the expression to count them. The same
  ** callback makes sure the doclists are loaded for each phrase.
  */
  rc = fts3ExprLoadDoclists(pCsr, &nList, 0);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  /* Now that it is known how many phrases there are, allocate and zero
  ** the required arrays using malloc().
  */

  nByte = sizeof(u8*)*nList +     /* apList */
      sizeof(int)*(nList) +       /* anToken */
      sizeof(int)*nList +         /* aiPrev */
      sizeof(int)*(nList+1);      /* anCnt */

  apList = (char **)sqlite3_malloc(nByte);
  if( !apList ){
    return SQLITE_NOMEM;
  }
  memset(apList, 0, nByte);
  anToken = (int *)&apList[nList];
  aiPrev = &anToken[nList];
  anCnt = &aiPrev[nList];

  /* Initialize the contents of the aiPrev and aiList arrays. */
  sCtx.pCsr = pCsr;
  sCtx.iCol = iCol;
  sCtx.apList = apList;
  sCtx.aiPrev = aiPrev;
  sCtx.anToken = anToken;
  sCtx.iPhrase = 0;
  (void)fts3ExprIterate(pCsr->pExpr, fts3SnippetFindPositions, (void *)&sCtx);

  for(i=0; i<nList; i++){
    if( apList[i] && aiPrev[i]>=0 ){
      *pmSeen |= (u64)1 << i;
    }
  }

  /* Load the first two chunks of data into the buffer. */
  memset(aBuffer, 0, SNIPPET_BUFFER_SIZE);
  fts3LoadSnippetBuffer(0, aBuffer, nList, apList, aiPrev);
  fts3LoadSnippetBuffer(SNIPPET_BUFFER_CHUNK, aBuffer, nList, apList, aiPrev);

  /* Set the initial contents of the highlight-mask and anCnt[] array. */
  for(i=1-nSnippet; i<=0; i++){
    fts3SnippetCnt(i, nSnippet, anCnt, aBuffer, anToken, &hlmask);
  }
  iBestScore = fts3SnippetScore(nList, anCnt, mCovered);
  besthlmask = hlmask;
  iBestPos = 0;
  bestcovmask = fts3SnippetMask(nList, anCnt);

  for(i=1; i<iEnd; i++){
    int iScore;

    if( 0==(i&(SNIPPET_BUFFER_CHUNK-1)) ){
      int iLoad = i + SNIPPET_BUFFER_CHUNK;
      if( fts3LoadSnippetBuffer(iLoad, aBuffer, nList, apList, aiPrev) ){
        iEnd = iLoad;
      }
    }

    /* Figure out how highly a snippet starting at token offset i scores
    ** according to fts3SnippetScore(). If it is higher than any previously
    ** considered position, save the current position, score and hlmask as 
    ** the best snippet candidate found so far.
    */
    fts3SnippetCnt(i, nSnippet, anCnt, aBuffer, anToken, &hlmask);
    iScore = fts3SnippetScore(nList, anCnt, mCovered);
    if( iScore>iBestScore ){
      iBestPos = i;
      iBestScore = iScore;
      besthlmask = hlmask;
      bestcovmask = fts3SnippetMask(nList, anCnt);
    }
  }

  sqlite3_free(apList);

  pFragment->iPos = iBestPos;
  pFragment->hlmask = besthlmask;
  pFragment->iCol = iCol;
  pFragment->covered = bestcovmask;
  *piScore = iBestScore;
  return SQLITE_OK;
}

typedef struct StrBuffer StrBuffer;
struct StrBuffer {
  char *z;
  int n;
................................................................................

static int fts3StringAppend(
  StrBuffer *pStr, 
  const char *zAppend, 
  int nAppend
){
  if( nAppend<0 ){
    nAppend = strlen(zAppend);
  }

  if( pStr->n+nAppend+1>=pStr->nAlloc ){
    int nAlloc = pStr->nAlloc+nAppend+100;
    char *zNew = sqlite3_realloc(pStr->z, nAlloc);
    if( !zNew ){
      return SQLITE_NOMEM;
................................................................................

  memcpy(&pStr->z[pStr->n], zAppend, nAppend);
  pStr->n += nAppend;
  pStr->z[pStr->n] = '\0';

  return SQLITE_OK;
}

int fts3SnippetShift(
  Fts3Table *pTab, 
  int nSnippet,
  const char *zDoc,
  int nDoc,
  int *piPos,
  u64 *pHlmask
){
  u64 hlmask = *pHlmask;

  if( hlmask ){
    int nLeft;
    int nRight;
    int nDesired;

    for(nLeft=0; !(hlmask & ((u64)1 << nLeft)); nLeft++);
    for(nRight=0; !(hlmask & ((u64)1 << (nSnippet-1-nRight))); nRight++);

    nDesired = (nLeft-nRight)/2;
    if( nDesired>0 ){
      int nShift;
      int iCurrent = 0;
      int rc;
      sqlite3_tokenizer_module *pMod;
      sqlite3_tokenizer_cursor *pC;

      pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
      rc = pMod->xOpen(pTab->pTokenizer, zDoc, nDoc, &pC);
      pC->pTokenizer = pTab->pTokenizer;
      while( rc==SQLITE_OK && iCurrent<(nSnippet+nDesired) ){
        const char *ZDUMMY; int DUMMY1, DUMMY2, DUMMY3;
        rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &DUMMY2, &DUMMY3, &iCurrent);
      }
      pMod->xClose(pC);
      if( rc!=SQLITE_OK && rc!=SQLITE_DONE ){
        return rc;
      }
      nShift = iCurrent-nSnippet;
      if( nShift>0 ){
        *piPos += nShift;
        *pHlmask = hlmask >> nShift;
      }
    }
  }
  return SQLITE_OK;
}

static int fts3SnippetText(
  Fts3Cursor *pCsr,               /* FTS3 Cursor */


  SnippetFragment *pFragment,     /* Snippet to extract */
  int nSnippet,                   /* Number of tokens in extracted snippet */


  const char *zOpen,              /* String inserted before highlighted term */
  const char *zClose,             /* String inserted after highlighted term */
  const char *zEllipsis,
  StrBuffer *pOut
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int rc;                         /* Return code */
  const char *zDoc;               /* Document text to extract snippet from */
  int nDoc;                       /* Size of zDoc in bytes */
  int iCurrent = 0;               /* Current token number of document */
  int iStart = 0;                 /* Byte offset of current token */

  int iEnd = 0;                   /* Byte offset of end of current token */
  int isShiftDone = 0;
  int iPos = pFragment->iPos;
  u64 hlmask = pFragment->hlmask;

  sqlite3_tokenizer_module *pMod; /* Tokenizer module methods object */
  sqlite3_tokenizer_cursor *pC;   /* Tokenizer cursor open on zDoc/nDoc */
  const char *ZDUMMY;             /* Dummy arguments used with tokenizer */
  int DUMMY1, DUMMY2, DUMMY3;     /* Dummy arguments used with tokenizer */
  
  zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, pFragment->iCol+1);
  if( zDoc==0 ){
    if( sqlite3_column_type(pCsr->pStmt, pFragment->iCol+1)!=SQLITE_NULL ){
      return SQLITE_NOMEM;
    }
    return SQLITE_OK;
  }
  nDoc = sqlite3_column_bytes(pCsr->pStmt, pFragment->iCol+1);

  /* Open a token cursor on the document. Read all tokens up to and 
  ** including token iPos (the first token of the snippet). Set variable
  ** iStart to the byte offset in zDoc of the start of token iPos.
  */
  pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
  rc = pMod->xOpen(pTab->pTokenizer, zDoc, nDoc, &pC);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  pC->pTokenizer = pTab->pTokenizer;





  while( rc==SQLITE_OK ){
    int iBegin;
    int iFin;
    rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &iBegin, &iFin, &iCurrent);

    if( rc==SQLITE_OK ){
      if( iCurrent<iPos ) continue;

      if( !isShiftDone ){
        int n = nDoc - iBegin;
        rc = fts3SnippetShift(pTab, nSnippet, &zDoc[iBegin], n, &iPos, &hlmask);
        if( rc!=SQLITE_OK || iCurrent<iPos ) continue;
      }
      if( iCurrent==iPos ){
        iStart = iEnd = iBegin;
      }

      if( iCurrent>=(iPos+nSnippet) ){
        rc = SQLITE_DONE;
      }else{
        iEnd = iFin;
        if( hlmask & ((u64)1 << (iCurrent-iPos)) ){
          if( fts3StringAppend(pOut, &zDoc[iStart], iBegin-iStart)
           || fts3StringAppend(pOut, zOpen, -1)
           || fts3StringAppend(pOut, &zDoc[iBegin], iEnd-iBegin)
           || fts3StringAppend(pOut, zClose, -1)
          ){
            rc = SQLITE_NOMEM;
          }
          iStart = iEnd;
        }
      }
    }
  }
  assert( rc!=SQLITE_OK );
  if( rc==SQLITE_DONE ){
    rc = fts3StringAppend(pOut, &zDoc[iStart], iEnd-iStart);
    if( rc==SQLITE_OK ){
      rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &DUMMY2, &DUMMY3, &iCurrent);
      if( rc==SQLITE_DONE ){
        rc = fts3StringAppend(pOut, &zDoc[iEnd], -1);
      }else if( rc==SQLITE_OK && zEllipsis ){
        rc = fts3StringAppend(pOut, zEllipsis, -1);
      }
    }
  }

  pMod->xClose(pC);





  return rc;
}


/*
** An instance of this structure is used to collect the 'global' part of
** the matchinfo statistics. The 'global' part consists of the following:
................................................................................
    int rc;
    int nPhrase;
    int nMatchinfo;

    g.pTab = pTab;
    g.nCol = pTab->nColumn;
    g.iPhrase = 0;
    rc = fts3ExprLoadDoclists(pCsr, &nPhrase, 0);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    nMatchinfo = 2 + 2*g.nCol*nPhrase;

    g.iPhrase = 0;
................................................................................
    (void)fts3ExprIterate(pCsr->pExpr, fts3ExprLocalMatchinfoCb, (void *)&g);
    pCsr->isMatchinfoOk = 0;
  }

  return SQLITE_OK;
}

void sqlite3Fts3Snippet(
  sqlite3_context *pCtx,          /* SQLite function call context */
  Fts3Cursor *pCsr,               /* Cursor object */
  const char *zStart,             /* Snippet start text - "<b>" */
  const char *zEnd,               /* Snippet end text - "</b>" */
  const char *zEllipsis,          /* Snippet ellipsis text - "<b>...</b>" */
  int iCol,                       /* Extract snippet from this column */
  int nToken                      /* Approximate number of tokens in snippet */
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int rc = SQLITE_OK;
  int i;
  StrBuffer res = {0, 0, 0};

  /* The returned text includes up to four fragments of text extracted from
  ** the data in the current row. The first iteration of the for(...) loop
  ** below attempts to locate a single fragment of text nToken tokens in 
  ** size that contains at least one instance of all phrases in the query
  ** expression that appear in the current row. If such a fragment of text
  ** cannot be found, the second iteration of the loop attempts to locate
  ** a pair of fragments, and so on.
  */
  int nSnippet = 0;               /* Number of fragments in this snippet */
  SnippetFragment aSnippet[4];    /* Maximum of 4 fragments per snippet */
  int nFToken = -1;               /* Number of tokens in each fragment */

  do {
    int iSnip;                    /* Loop counter 0..nSnippet-1 */
    u64 mCovered = 0;             /* Bitmask of phrases covered by snippet */
    u64 mSeen = 0;                /* Bitmask of phrases seen by BestSnippet() */

    nSnippet++;
    nFToken = (nToken+nSnippet-1) / nSnippet;

    for(iSnip=0; iSnip<nSnippet; iSnip++){
      int iBestScore = -1;        /* Best score of columns checked so far */
      int iRead;                  /* Used to iterate through columns */
      SnippetFragment *pFragment = &aSnippet[iSnip];

      memset(pFragment, 0, sizeof(*pFragment));

      /* Loop through all columns of the table being considered for snippets.
      ** If the iCol argument to this function was negative, this means all
      ** columns of the FTS3 table. Otherwise, only column iCol is considered.
      */
      for(iRead=0; iRead<pTab->nColumn; iRead++){
        SnippetFragment sF;
        int iS;

        if( iCol>=0 && iRead!=iCol ) continue;

        /* Find the best snippet of nFToken tokens in column iRead. */
        rc = fts3BestSnippet(nFToken, pCsr, iRead, mCovered, &mSeen, &sF, &iS);
        if( rc!=SQLITE_OK ){
          goto snippet_out;
        }
        if( iS>iBestScore ){
          *pFragment = sF;
          iBestScore = iS;
        }
      }

      mCovered |= pFragment->covered;
    }

    /* If all query phrases seen by fts3BestSnippet() are present in at least
    ** one of the nSnippet snippet fragments, break out of the loop.
    */
    assert( (mCovered&mSeen)==mCovered );
    if( mSeen==mCovered ) break;
  }while( nSnippet<SizeofArray(aSnippet) );

  assert( nFToken>0 );

  for(i=0; i<nSnippet && rc==SQLITE_OK; i++){
    SnippetFragment *p = &aSnippet[i];
    const char *zTail = ((i==nSnippet-1) ? zEllipsis : 0);

    if( i>0 || p->iPos>0 ){
      fts3StringAppend(&res, zEllipsis, -1);
    }
    rc = fts3SnippetText(pCsr, p, nFToken, zStart, zEnd, zTail, &res);
  }

 snippet_out:
  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pCtx, rc);
    sqlite3_free(res.z);
  }else{
    sqlite3_result_text(pCtx, res.z, -1, sqlite3_free);
  }
}


typedef struct TermOffset TermOffset;
struct TermOffset {
  char *pList;                    /* Position-list */
  int iPos;                       /* Position just read from pList */
  int iOff;
};
typedef struct TermOffsetCtx TermOffsetCtx;

struct TermOffsetCtx {
  int iCol;                       /* Column of table to populate aTerm for */
  int iTerm;
  sqlite3_int64 iDocid;
  TermOffset *aTerm;
};

/*
** This function is an fts3ExprIterate() callback used by sqlite3Fts3Offsets().
*/
static int fts3ExprTermOffsetInit(Fts3Expr *pExpr, void *ctx){
  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 */

  pList = sqlite3Fts3FindPositions(pExpr, p->iDocid, p->iCol);
  nTerm = pExpr->pPhrase->nToken;
  if( pList ){
    fts3GetDeltaPosition(&pList, &iPos);
    assert( iPos>=0 );
  }

  for(iTerm=0; iTerm<nTerm; iTerm++){
    TermOffset *pT = &p->aTerm[p->iTerm++];
    pT->iOff = nTerm-iTerm-1;
    pT->pList = pList;
    pT->iPos = iPos;
  }

  return SQLITE_OK;
}

/*
** Implementation of offsets() function.
*/
void sqlite3Fts3Offsets(
  sqlite3_context *pCtx,          /* SQLite function call context */
  Fts3Cursor *pCsr                /* Cursor object */
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  sqlite3_tokenizer_module const *pMod = pTab->pTokenizer->pModule;
  const char *ZDUMMY;
  int NDUMMY;

  int rc;                         /* Return Code */
  int nToken;                     /* Number of tokens in query */
  int iCol;                       /* Column currently being processed */
  StrBuffer res = {0, 0, 0};      /* Result string */

  TermOffsetCtx sCtx;
  memset(&sCtx, 0, sizeof(sCtx));

  assert( pCsr->isRequireSeek==0 );

  /* Count the number of terms in the query */
  rc = fts3ExprLoadDoclists(pCsr, 0, &nToken);
  if( rc!=SQLITE_OK ) goto offsets_out;

  /* Allocate the array of TermOffset iterators. */
  sCtx.aTerm = (TermOffset *)sqlite3_malloc(sizeof(TermOffset)*nToken);
  if( 0==sCtx.aTerm ){
    rc = SQLITE_NOMEM;
    goto offsets_out;
  }
  sCtx.iDocid = pCsr->iPrevId;

  for(iCol=0; iCol<pTab->nColumn; iCol++){
    sqlite3_tokenizer_cursor *pC; /* Tokenizer cursor */
    int iStart;
    int iEnd;
    int iCurrent;
    const char *zDoc;
    int nDoc;


    /* Initialize the contents of sCtx.aTerm[] for column iCol. */
    sCtx.iCol = iCol;
    sCtx.iTerm = 0;
    rc = fts3ExprIterate(pCsr->pExpr, fts3ExprTermOffsetInit, (void *)&sCtx);
    if( rc!=SQLITE_OK ) goto offsets_out;


    /* Initialize a tokenizer iterator to iterate through column iCol. */
    zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol+1);
    nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol+1);
    rc = pMod->xOpen(pTab->pTokenizer, zDoc, nDoc, &pC);
    if( rc!=SQLITE_OK ) goto offsets_out;
    pC->pTokenizer = pTab->pTokenizer;

    rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
    while( rc==SQLITE_OK ){
      int i;                      /* Used to loop through terms */
      int iMinPos = 0x7FFFFFFF;   /* Position of next token */
      TermOffset *pTerm = 0;      /* TermOffset associated with next token */

      for(i=0; i<nToken; i++){
        TermOffset *pT = &sCtx.aTerm[i];
        if( pT->pList && (pT->iPos-pT->iOff)<iMinPos ){
          iMinPos = pT->iPos-pT->iOff;
          pTerm = pT;
        }
      }

      if( !pTerm ){
        /* All offsets for this column have been gathered. */
        break;
      }else{
        assert( iCurrent<=iMinPos );
        if( 0==(0xFE&*pTerm->pList) ){
          pTerm->pList = 0;
        }else{
          fts3GetDeltaPosition(&pTerm->pList, &pTerm->iPos);
        }
        while( rc==SQLITE_OK && iCurrent<iMinPos ){
          rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
        }
        if( rc==SQLITE_OK ){


          char aBuffer[64];
          sqlite3_snprintf(sizeof(aBuffer), aBuffer, 
              "%d %d %d %d ", iCol, pTerm-sCtx.aTerm, iStart, iEnd-iStart
          );
          fts3StringAppend(&res, aBuffer, -1);
        }
      }
    }
    if( rc==SQLITE_DONE ){
      rc = SQLITE_ERROR;
    }

    pMod->xClose(pC);
    if( rc!=SQLITE_OK ) goto offsets_out;
  }

 offsets_out:
  sqlite3_free(sCtx.aTerm);
  assert( rc!=SQLITE_DONE );
  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pCtx,  rc);
    sqlite3_free(res.z);
  }else{
    sqlite3_result_text(pCtx, res.z, res.n-1, sqlite3_free);
  }
  return;
}

void sqlite3Fts3Matchinfo(sqlite3_context *pContext, Fts3Cursor *pCsr){
  int rc = fts3GetMatchinfo(pCsr);
  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pContext, rc);
  }else{
    int n = sizeof(u32)*(2+pCsr->aMatchinfo[0]*pCsr->aMatchinfo[1]*2);
    sqlite3_result_blob(pContext, pCsr->aMatchinfo, n, SQLITE_TRANSIENT);
  }
}

#endif

Changes to test/fts3ac.test.

1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200

1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
  }
} {{Alert Posted 10:00 AM November 20,2000: E-<b>GAS</b> Request <b>Reminder</b>}}
do_test fts3ac-4.2 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'christmas candlelight'
  }
} {{<b>...</b> place.? What do you think about going here <b>Christmas</b> 
eve?? They have an 11:00 a.m. service and a <b>candlelight</b> service at 5:00 p.m., 
among others. <b>...</b>}}

do_test fts3ac-4.3 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'deal sheet potential reuse'
  }
} {{EOL-Accenture <b>Deal</b> <b>Sheet</b> <b>...</b> intent
     Review Enron asset base for <b>potential</b> <b>reuse</b>/ licensing
     Contract negotiations <b>...</b>}}
do_test fts3ac-4.4 {
  execsql {
    SELECT snippet(email,'<<<','>>>',' ') FROM email
     WHERE email MATCH 'deal sheet potential reuse'
  }
} {{EOL-Accenture <<<Deal>>> <<<Sheet>>>  intent
     Review Enron asset base for <<<potential>>> <<<reuse>>>/ licensing
     Contract negotiations  }}
do_test fts3ac-4.5 {
  execsql {
    SELECT snippet(email,'<<<','>>>',' ') FROM email
     WHERE email MATCH 'first things'
  }
} {{Re: <<<First>>> Polish Deal!  Congrats!  <<<Things>>> seem to be building rapidly now on the  }}
do_test fts3ac-4.6 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'chris is here'
  }
} {{<b>chris</b>.germany@enron.com <b>...</b> Sounds good to me.  I bet this <b>is</b> next to the Warick?? Hotel. <b>...</b> place.? What do you think about going <b>here</b> Christmas 
eve?? They have an 11:00 a.m. <b>...</b>}}
do_test fts3ac-4.7 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH '"pursuant to"'
  }
} {{Erin:

<b>Pursuant</b> <b>to</b> your request, attached are the Schedule to <b>...</b>}}
do_test fts3ac-4.8 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'ancillary load davis'
  }
} {{pete.<b>davis</b>@enron.com <b>...</b> Start Date: 4/22/01; HourAhead hour: 3;  No <b>ancillary</b> schedules awarded.  
Variances detected.
Variances detected in <b>Load</b> schedule.

    LOG MESSAGES:

PARSING <b>...</b>}}

# Combinations of AND and OR operators:
#
do_test fts3ac-5.1 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'questar enron OR com'
  }
} {{matt.smith@<b>enron</b>.<b>com</b> <b>...</b> six reports:  

31 Keystone Receipts
15 <b>Questar</b> Pipeline
40 Rockies Production
22 West_2 <b>...</b>}}

do_test fts3ac-5.2 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'enron OR com questar'
  }
} {{matt.smith@<b>enron</b>.<b>com</b> <b>...</b> six reports:  

31 Keystone Receipts
15 <b>Questar</b> Pipeline
40 Rockies Production
22 West_2 <b>...</b>}}

finish_test







|
|
<






<
|
|





<
|
|





|





|
|







|





|
<
<

<
<
|








|
<
<

<
|
>





|
<
<

<
|


1127
1128
1129
1130
1131
1132
1133
1134
1135

1136
1137
1138
1139
1140
1141

1142
1143
1144
1145
1146
1147
1148

1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177


1178


1179
1180
1181
1182
1183
1184
1185
1186
1187
1188


1189

1190
1191
1192
1193
1194
1195
1196
1197


1198

1199
1200
1201
  }
} {{Alert Posted 10:00 AM November 20,2000: E-<b>GAS</b> Request <b>Reminder</b>}}
do_test fts3ac-4.2 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'christmas candlelight'
  }
} {{<b>...</b>here <b>Christmas</b> 
eve?? They have an 11:00 a.m. service and a <b>candlelight</b> service<b>...</b>}}


do_test fts3ac-4.3 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'deal sheet potential reuse'
  }

} {{EOL-Accenture <b>Deal</b> <b>Sheet</b><b>...</b>asset base for <b>potential</b> <b>reuse</b>/ licensing
     Contract negotiations<b>...</b>}}
do_test fts3ac-4.4 {
  execsql {
    SELECT snippet(email,'<<<','>>>',' ') FROM email
     WHERE email MATCH 'deal sheet potential reuse'
  }

} {{EOL-Accenture <<<Deal>>> <<<Sheet>>> asset base for <<<potential>>> <<<reuse>>>/ licensing
     Contract negotiations }}
do_test fts3ac-4.5 {
  execsql {
    SELECT snippet(email,'<<<','>>>',' ') FROM email
     WHERE email MATCH 'first things'
  }
} {{Re: <<<First>>> Polish Deal! Congrats!  <<<Things>>> seem to be building rapidly now }}
do_test fts3ac-4.6 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'chris is here'
  }
} {{<b>...</b><b>chris</b>.germany@enron.com'" <<b>chris</b><b>...</b>bet this <b>is</b> next to<b>...</b>about going <b>here</b> Christmas 
eve<b>...</b>}}
do_test fts3ac-4.7 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH '"pursuant to"'
  }
} {{Erin:

<b>Pursuant</b> <b>to</b> your request, attached are the Schedule to the ISDA Master Agreement, together<b>...</b>}}
do_test fts3ac-4.8 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'ancillary load davis'
  }
} {{pete.<b>davis</b>@enron.com<b>...</b>3;  No <b>ancillary</b> schedules awarded<b>...</b>detected in <b>Load</b> schedule.





    LOG<b>...</b>}}

# Combinations of AND and OR operators:
#
do_test fts3ac-5.1 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'questar enron OR com'
  }
} {{matt.smith@<b>enron</b>.<b>com</b><b>...</b>31 Keystone Receipts


15 <b>Questar</b> Pipeline

40 Rockies<b>...</b>}}

do_test fts3ac-5.2 {
  execsql {
    SELECT snippet(email) FROM email
     WHERE email MATCH 'enron OR com questar'
  }
} {{matt.smith@<b>enron</b>.<b>com</b><b>...</b>31 Keystone Receipts


15 <b>Questar</b> Pipeline

40 Rockies<b>...</b>}}

finish_test

Changes to test/fts3al.test.

49
50
51
52
53
54
55




56
57
58
59
60
61
62
63
64
65
66
67
68
69
# exercised.  The version with a couple extra spaces should cause the
# other isspace() call to be exercised.  [Both cases have been tested
# in the debugger, but I'm hoping to continue to catch it if simple
# constant changes change things slightly.
#
# The trailing and leading hi-bit chars help with code which tests for
# isspace() to coalesce multiple spaces.





set word "\x80xxxxx\x80xxxxx\x80xxxxx\x80xxxxx\x80xxxxx\x80xxxxx\x80"
set phrase1 "$word $word $word target $word $word $word"
set phrase2 "$word $word $word    target    $word $word $word"

db eval {CREATE VIRTUAL TABLE t4 USING fts3(content)}
db eval "INSERT INTO t4 (content) VALUES ('$phrase1')"
db eval "INSERT INTO t4 (content) VALUES ('$phrase2')"

do_test fts3al-1.4 {
  execsql {SELECT rowid, length(snippet(t4)) FROM t4 WHERE t4 MATCH 'target'}
} {1 111 2 117}

finish_test







>
>
>
>











|


49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
# exercised.  The version with a couple extra spaces should cause the
# other isspace() call to be exercised.  [Both cases have been tested
# in the debugger, but I'm hoping to continue to catch it if simple
# constant changes change things slightly.
#
# The trailing and leading hi-bit chars help with code which tests for
# isspace() to coalesce multiple spaces.
#
# UPDATE: The above is no longer true; there is no such code in fts3.
# But leave the test in just the same.
# 

set word "\x80xxxxx\x80xxxxx\x80xxxxx\x80xxxxx\x80xxxxx\x80xxxxx\x80"
set phrase1 "$word $word $word target $word $word $word"
set phrase2 "$word $word $word    target    $word $word $word"

db eval {CREATE VIRTUAL TABLE t4 USING fts3(content)}
db eval "INSERT INTO t4 (content) VALUES ('$phrase1')"
db eval "INSERT INTO t4 (content) VALUES ('$phrase2')"

do_test fts3al-1.4 {
  execsql {SELECT rowid, length(snippet(t4)) FROM t4 WHERE t4 MATCH 'target'}
} {1 241 2 247}

finish_test

Changes to test/fts3near.test.

72
73
74
75
76
77
78











79
80
81
82
83
84
85
...
150
151
152
153
154
155
156

157
158
159
160
161
162
163
...
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
do_test fts3near-1.14 {
  execsql {SELECT docid FROM t1 WHERE content MATCH 'four NEAR four'}
} {} 
do_test fts3near-1.15 {
  execsql {SELECT docid FROM t1 WHERE content MATCH 'one NEAR two NEAR one'}
} {3} 













# Output format of the offsets() function:
#
#     <column number> <term number> <starting offset> <number of bytes>
#
db eval {
  INSERT INTO t1(content) VALUES('A X B C D A B');
................................................................................
  execsql {SELECT offsets(t1) FROM t1 WHERE content MATCH 'two NEAR/2 three'}
} {{0 0 4 3 0 1 8 5 0 0 14 3 0 1 27 5}}
do_test fts3near-3.6 {
  execsql {
    SELECT offsets(t1) FROM t1 WHERE content MATCH 'three NEAR/0 "two four"'
  }
} {{0 0 8 5 0 1 14 3 0 2 18 4}}

do_test fts3near-3.7 {
  execsql {
    SELECT offsets(t1) FROM t1 WHERE content MATCH '"two four" NEAR/0 three'}
} {{0 2 8 5 0 0 14 3 0 1 18 4}}

db eval {
  INSERT INTO t1(content) VALUES('
................................................................................
    CSS2 builds on CSS1 (see [CSS1]) and, with very few exceptions, all valid CSS1 style sheets are valid CSS2 style sheets. CSS2 supports media-specific style sheets so that authors may tailor the presentation of their documents to visual browsers, aural devices, printers, braille devices, handheld devices, etc. This specification also supports content positioning, downloadable fonts, table layout, features for internationalization, automatic counters and numbering, and some properties related to user interface.
  ') 
}
do_test fts3near-4.1 {
  execsql {
    SELECT snippet(t1) FROM t1 WHERE content MATCH 'specification NEAR supports'
  }
} {{<b>...</b> devices, handheld devices, etc. This <b>specification</b> also <b>supports</b> content positioning, downloadable fonts, <b>...</b>}}

do_test fts3near-5.1 {
  execsql {
    SELECT docid FROM t1 WHERE content MATCH 'specification attach'
  }
} {2}
do_test fts3near-5.2 {







>
>
>
>
>
>
>
>
>
>
>







 







>







 







|







72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
...
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
...
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
do_test fts3near-1.14 {
  execsql {SELECT docid FROM t1 WHERE content MATCH 'four NEAR four'}
} {} 
do_test fts3near-1.15 {
  execsql {SELECT docid FROM t1 WHERE content MATCH 'one NEAR two NEAR one'}
} {3} 

do_test fts3near-1.16 {
  execsql {
    SELECT docid FROM t1 WHERE content MATCH '"one three" NEAR/0 "four five"'
  }
} {1} 
do_test fts3near-1.17 {
  execsql {
    SELECT docid FROM t1 WHERE content MATCH '"four five" NEAR/0 "one three"'
  }
} {1} 


# Output format of the offsets() function:
#
#     <column number> <term number> <starting offset> <number of bytes>
#
db eval {
  INSERT INTO t1(content) VALUES('A X B C D A B');
................................................................................
  execsql {SELECT offsets(t1) FROM t1 WHERE content MATCH 'two NEAR/2 three'}
} {{0 0 4 3 0 1 8 5 0 0 14 3 0 1 27 5}}
do_test fts3near-3.6 {
  execsql {
    SELECT offsets(t1) FROM t1 WHERE content MATCH 'three NEAR/0 "two four"'
  }
} {{0 0 8 5 0 1 14 3 0 2 18 4}}
breakpoint
do_test fts3near-3.7 {
  execsql {
    SELECT offsets(t1) FROM t1 WHERE content MATCH '"two four" NEAR/0 three'}
} {{0 2 8 5 0 0 14 3 0 1 18 4}}

db eval {
  INSERT INTO t1(content) VALUES('
................................................................................
    CSS2 builds on CSS1 (see [CSS1]) and, with very few exceptions, all valid CSS1 style sheets are valid CSS2 style sheets. CSS2 supports media-specific style sheets so that authors may tailor the presentation of their documents to visual browsers, aural devices, printers, braille devices, handheld devices, etc. This specification also supports content positioning, downloadable fonts, table layout, features for internationalization, automatic counters and numbering, and some properties related to user interface.
  ') 
}
do_test fts3near-4.1 {
  execsql {
    SELECT snippet(t1) FROM t1 WHERE content MATCH 'specification NEAR supports'
  }
} {{<b>...</b>braille devices, handheld devices, etc. This <b>specification</b> also <b>supports</b> content positioning, downloadable fonts, table layout<b>...</b>}}

do_test fts3near-5.1 {
  execsql {
    SELECT docid FROM t1 WHERE content MATCH 'specification attach'
  }
} {2}
do_test fts3near-5.2 {

Added test/fts3snippet.test.









































































































































>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68

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

# If SQLITE_ENABLE_FTS3 is defined, omit this file.
ifcapable !fts3 { finish_test ; return }

do_test fts3snippet-1.1 {
  execsql {
    CREATE VIRTUAL TABLE ft USING fts3;
    INSERT INTO ft VALUES('xxx xxx xxx xxx');
  }
} {}

proc normalize {L} {
  set ret [list]
  foreach l $L {lappend ret $l}
  return $ret
}

do_test fts3snippet-1.2 {
  execsql { SELECT offsets(ft) FROM ft WHERE ft MATCH 'xxx' }
} {{0 0 0 3 0 0 4 3 0 0 8 3 0 0 12 3}}

do_test fts3snippet-1.3 {
  execsql { SELECT offsets(ft) FROM ft WHERE ft MATCH '"xxx xxx"' }
} [list [normalize {
    0 0  0 3 
    0 0  4 3 
    0 1  4 3 
    0 0  8 3 
    0 1  8 3 
    0 1 12 3
}]]


do_test fts3snippet-1.4 {
  execsql { SELECT offsets(ft) FROM ft WHERE ft MATCH '"xxx xxx" xxx' }
} [list [normalize {
    0 0  0 3 
    0 2  0 3 
    0 0  4 3 
    0 1  4 3 
    0 2  4 3 
    0 0  8 3 
    0 1  8 3 
    0 2  8 3 
    0 1 12 3
    0 2 12 3
}]]

do_test fts3snippet-1.5 {
  execsql { SELECT offsets(ft) FROM ft WHERE ft MATCH 'xxx "xxx xxx"' }
} [list [normalize {
    0 0  0 3 
    0 1  0 3 
    0 0  4 3 
    0 1  4 3 
    0 2  4 3 
    0 0  8 3 
    0 1  8 3 
    0 2  8 3 
    0 0 12 3
    0 2 12 3
}]]

finish_test