Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
| Comment: | Bias the fts5 snippet() function to return snippets that look like they start at the start of sentences. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | fts5-snippet-bias |
| Files: | files | file ages | folders |
| SHA1: |
60de159476edbd48dc363f7f77f09c32 |
| User & Date: | dan 2016-08-17 19:05:12 |
Context
|
2016-08-18
| ||
| 14:47 | Adjust some tests to account for recent changes to the fts5 snippet function. check-in: 184ecbe9 user: dan tags: fts5-snippet-bias | |
|
2016-08-17
| ||
| 19:05 | Bias the fts5 snippet() function to return snippets that look like they start at the start of sentences. check-in: 60de1594 user: dan tags: fts5-snippet-bias | |
| 11:14 | Fix a problem in the fts5 snippet() auxiliary function. check-in: a861713c user: dan tags: trunk | |
Changes
Changes to ext/fts5/fts5_aux.c.
241 242 243 244 245 246 247 248 249 250 251 252 253 254 ... 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 ... 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 |
if( rc!=SQLITE_OK ){
sqlite3_result_error_code(pCtx, rc);
}
}
/*
** End of highlight() implementation.
**************************************************************************/
/*
** Implementation of snippet() function.
*/
static void fts5SnippetFunction(
const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
Fts5Context *pFts, /* First arg to pass to pApi functions */
................................................................................
int nToken; /* 5th argument to snippet() */
int nInst = 0; /* Number of instance matches this row */
int i; /* Used to iterate through instances */
int nPhrase; /* Number of phrases in query */
unsigned char *aSeen; /* Array of "seen instance" flags */
int iBestCol; /* Column containing best snippet */
int iBestStart = 0; /* First token of best snippet */
int iBestLast; /* Last token of best snippet */
int nBestScore = 0; /* Score of best snippet */
int nColSize = 0; /* Total size of iBestCol in tokens */
if( nVal!=5 ){
const char *zErr = "wrong number of arguments to function snippet()";
sqlite3_result_error(pCtx, zErr, -1);
return;
}
memset(&ctx, 0, sizeof(HighlightContext));
iCol = sqlite3_value_int(apVal[0]);
ctx.zOpen = (const char*)sqlite3_value_text(apVal[1]);
ctx.zClose = (const char*)sqlite3_value_text(apVal[2]);
zEllips = (const char*)sqlite3_value_text(apVal[3]);
nToken = sqlite3_value_int(apVal[4]);
iBestLast = nToken-1;
iBestCol = (iCol>=0 ? iCol : 0);
nPhrase = pApi->xPhraseCount(pFts);
aSeen = sqlite3_malloc(nPhrase);
if( aSeen==0 ){
rc = SQLITE_NOMEM;
}
if( rc==SQLITE_OK ){
rc = pApi->xInstCount(pFts, &nInst);
}
for(i=0; rc==SQLITE_OK && i<nInst; i++){
int ip, iSnippetCol, iStart;
memset(aSeen, 0, nPhrase);
rc = pApi->xInst(pFts, i, &ip, &iSnippetCol, &iStart);
if( rc==SQLITE_OK && (iCol<0 || iSnippetCol==iCol) ){
int nScore = 1000;
int iLast = iStart - 1 + pApi->xPhraseSize(pFts, ip);
int j;
aSeen[ip] = 1;
for(j=i+1; rc==SQLITE_OK && j<nInst; j++){
int ic; int io; int iFinal;
rc = pApi->xInst(pFts, j, &ip, &ic, &io);
iFinal = io + pApi->xPhraseSize(pFts, ip) - 1;
if( rc==SQLITE_OK && ic==iSnippetCol && iLast<iStart+nToken ){
nScore += aSeen[ip] ? 1000 : 1;
aSeen[ip] = 1;
if( iFinal>iLast ) iLast = iFinal;
}
}
if( rc==SQLITE_OK && nScore>nBestScore ){
iBestCol = iSnippetCol;
iBestStart = iStart;
iBestLast = iLast;
nBestScore = nScore;
}
}
}
if( rc==SQLITE_OK ){
rc = pApi->xColumnSize(pFts, iBestCol, &nColSize);
}
if( rc==SQLITE_OK ){
rc = pApi->xColumnText(pFts, iBestCol, &ctx.zIn, &ctx.nIn);
}
if( ctx.zIn ){
if( rc==SQLITE_OK ){
rc = fts5CInstIterInit(pApi, pFts, iBestCol, &ctx.iter);
}
if( (iBestStart+nToken-1)>iBestLast ){
iBestStart -= (iBestStart+nToken-1-iBestLast) / 2;
}
if( iBestStart+nToken>nColSize ){
iBestStart = nColSize - nToken;
}
if( iBestStart<0 ) iBestStart = 0;
ctx.iRangeStart = iBestStart;
ctx.iRangeEnd = iBestStart + nToken - 1;
if( iBestStart>0 ){
fts5HighlightAppend(&rc, &ctx, zEllips, -1);
}
................................................................................
rc = pApi->xTokenize(pFts, ctx.zIn, ctx.nIn, (void*)&ctx,fts5HighlightCb);
}
if( ctx.iRangeEnd>=(nColSize-1) ){
fts5HighlightAppend(&rc, &ctx, &ctx.zIn[ctx.iOff], ctx.nIn - ctx.iOff);
}else{
fts5HighlightAppend(&rc, &ctx, zEllips, -1);
}
if( rc==SQLITE_OK ){
sqlite3_result_text(pCtx, (const char*)ctx.zOut, -1, SQLITE_TRANSIENT);
}else{
sqlite3_result_error_code(pCtx, rc);
}
sqlite3_free(ctx.zOut);
}
sqlite3_free(aSeen);
}
/************************************************************************/
/*
** The first time the bm25() function is called for a query, an instance
** of the following structure is allocated and populated.
|
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > < > > > < < > > > > > > > > > > > > > > > > > > | < > | < < > > > > > | < < < | < < < < < < < > > > > > > > > > > > > > | > | | < < > > < < < < < < < < < < < | | | | | | | < > |
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 ... 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 ... 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 |
if( rc!=SQLITE_OK ){
sqlite3_result_error_code(pCtx, rc);
}
}
/*
** End of highlight() implementation.
**************************************************************************/
/*
** Context object passed to the fts5SentenceFinderCb() function.
*/
typedef struct Fts5SFinder Fts5SFinder;
struct Fts5SFinder {
int iPos; /* Current token position */
int nFirstAlloc; /* Allocated size of aFirst[] */
int nFirst; /* Number of entries in aFirst[] */
int *aFirst; /* Array of first token in each sentence */
const char *zDoc; /* Document being tokenized */
};
/*
** Add an entry to the Fts5SFinder.aFirst[] array. Grow the array if
** necessary. Return SQLITE_OK if successful, or SQLITE_NOMEM if an
** error occurs.
*/
static int fts5SentenceFinderAdd(Fts5SFinder *p, int iAdd){
if( p->nFirstAlloc==p->nFirst ){
int nNew = p->nFirstAlloc ? p->nFirstAlloc*2 : 64;
int *aNew;
aNew = (int*)sqlite3_realloc(p->aFirst, nNew*sizeof(int));
if( aNew==0 ) return SQLITE_NOMEM;
p->aFirst = aNew;
p->nFirstAlloc = nNew;
}
p->aFirst[p->nFirst++] = iAdd;
return SQLITE_OK;
}
/*
** This function is an xTokenize() callback used by the auxiliary snippet()
** function. Its job is to identify tokens that are the first in a sentence.
** For each such token, an entry is added to the SFinder.aFirst[] array.
*/
static int fts5SentenceFinderCb(
void *pContext, /* Pointer to HighlightContext object */
int tflags, /* Mask of FTS5_TOKEN_* flags */
const char *pToken, /* Buffer containing token */
int nToken, /* Size of token in bytes */
int iStartOff, /* Start offset of token */
int iEndOff /* End offset of token */
){
int rc = SQLITE_OK;
if( (tflags & FTS5_TOKEN_COLOCATED)==0 ){
Fts5SFinder *p = (Fts5SFinder*)pContext;
if( p->iPos>0 ){
int i;
char c = 0;
for(i=iStartOff-1; i>=0; i--){
c = p->zDoc[i];
if( c!=' ' && c!='\t' && c!='\n' && c!='\r' ) break;
}
if( i!=iStartOff-1 && (c=='.' || c==':') ){
rc = fts5SentenceFinderAdd(p, p->iPos);
}
}else{
rc = fts5SentenceFinderAdd(p, 0);
}
p->iPos++;
}
return rc;
}
static int fts5SnippetScore(
const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
Fts5Context *pFts, /* First arg to pass to pApi functions */
int nDocsize, /* Size of column in tokens */
unsigned char *aSeen, /* Array with one element per query phrase */
int iCol, /* Column to score */
int iPos, /* Starting offset to score */
int nToken, /* Max tokens per snippet */
int *pnScore, /* OUT: Score */
int *piPos /* OUT: Adjusted offset */
){
int rc;
int i;
int ip = 0;
int ic = 0;
int iOff = 0;
int iFirst = -1;
int nInst;
int nScore = 0;
rc = pApi->xInstCount(pFts, &nInst);
for(i=0; i<nInst && rc==SQLITE_OK; i++){
rc = pApi->xInst(pFts, i, &ip, &ic, &iOff);
if( rc==SQLITE_OK && ic==iCol && iOff>=iPos && iOff<(iPos+nToken) ){
nScore += (aSeen[ip] ? 1 : 1000);
aSeen[ip] = 1;
if( iFirst<0 ) iFirst = iOff;
}
}
*pnScore = nScore;
if( piPos ){
int iLast = iOff + pApi->xPhraseSize(pFts, ip);
int iAdj = iFirst - (nToken - (iLast-iFirst)) / 2;
if( (iAdj+nToken)>nDocsize ) iAdj = nDocsize - nToken;
if( iAdj<0 ) iAdj = 0;
*piPos = iAdj;
}
return rc;
}
/*
** Implementation of snippet() function.
*/
static void fts5SnippetFunction(
const Fts5ExtensionApi *pApi, /* API offered by current FTS version */
Fts5Context *pFts, /* First arg to pass to pApi functions */
................................................................................
int nToken; /* 5th argument to snippet() */
int nInst = 0; /* Number of instance matches this row */
int i; /* Used to iterate through instances */
int nPhrase; /* Number of phrases in query */
unsigned char *aSeen; /* Array of "seen instance" flags */
int iBestCol; /* Column containing best snippet */
int iBestStart = 0; /* First token of best snippet */
int nBestScore = 0; /* Score of best snippet */
int nColSize = 0; /* Total size of iBestCol in tokens */
Fts5SFinder sFinder; /* Used to find the beginnings of sentences */
int nCol;
if( nVal!=5 ){
const char *zErr = "wrong number of arguments to function snippet()";
sqlite3_result_error(pCtx, zErr, -1);
return;
}
nCol = pApi->xColumnCount(pFts);
memset(&ctx, 0, sizeof(HighlightContext));
iCol = sqlite3_value_int(apVal[0]);
ctx.zOpen = (const char*)sqlite3_value_text(apVal[1]);
ctx.zClose = (const char*)sqlite3_value_text(apVal[2]);
zEllips = (const char*)sqlite3_value_text(apVal[3]);
nToken = sqlite3_value_int(apVal[4]);
iBestCol = (iCol>=0 ? iCol : 0);
nPhrase = pApi->xPhraseCount(pFts);
aSeen = sqlite3_malloc(nPhrase);
if( aSeen==0 ){
rc = SQLITE_NOMEM;
}
if( rc==SQLITE_OK ){
rc = pApi->xInstCount(pFts, &nInst);
}
memset(&sFinder, 0, sizeof(Fts5SFinder));
for(i=0; i<nCol; i++){
if( iCol<0 || iCol==i ){
int nDoc;
int nDocsize;
int ii;
sFinder.iPos = 0;
sFinder.nFirst = 0;
rc = pApi->xColumnText(pFts, i, &sFinder.zDoc, &nDoc);
if( rc!=SQLITE_OK ) break;
rc = pApi->xTokenize(pFts,
sFinder.zDoc, nDoc, (void*)&sFinder,fts5SentenceFinderCb
);
if( rc!=SQLITE_OK ) break;
rc = pApi->xColumnSize(pFts, i, &nDocsize);
if( rc!=SQLITE_OK ) break;
for(ii=0; rc==SQLITE_OK && ii<sFinder.nFirst; ii++){
int nScore;
memset(aSeen, 0, nPhrase);
rc = fts5SnippetScore(pApi, pFts, nDocsize, aSeen, i,
sFinder.aFirst[ii], nToken, &nScore, 0
);
/* Bonus of 100 points for starting at the start of a sentence */
nScore += 100;
if( rc==SQLITE_OK && nScore>nBestScore ){
nBestScore = nScore;
iBestCol = i;
iBestStart = sFinder.aFirst[ii];
nColSize = nDocsize;
}
}
for(ii=0; rc==SQLITE_OK && ii<nInst; ii++){
int ip, ic, io;
int nScore;
rc = pApi->xInst(pFts, ii, &ip, &ic, &io);
if( ic!=i || rc!=SQLITE_OK ) continue;
memset(aSeen, 0, nPhrase);
rc = fts5SnippetScore(pApi, pFts, nDocsize, aSeen, i,
io, nToken, &nScore, &io
);
if( rc==SQLITE_OK && nScore>nBestScore ){
nBestScore = nScore;
iBestCol = i;
iBestStart = io;
nColSize = nDocsize;
}
}
}
}
if( rc==SQLITE_OK ){
rc = pApi->xColumnText(pFts, iBestCol, &ctx.zIn, &ctx.nIn);
}
if( ctx.zIn ){
if( rc==SQLITE_OK ){
rc = fts5CInstIterInit(pApi, pFts, iBestCol, &ctx.iter);
}
ctx.iRangeStart = iBestStart;
ctx.iRangeEnd = iBestStart + nToken - 1;
if( iBestStart>0 ){
fts5HighlightAppend(&rc, &ctx, zEllips, -1);
}
................................................................................
rc = pApi->xTokenize(pFts, ctx.zIn, ctx.nIn, (void*)&ctx,fts5HighlightCb);
}
if( ctx.iRangeEnd>=(nColSize-1) ){
fts5HighlightAppend(&rc, &ctx, &ctx.zIn[ctx.iOff], ctx.nIn - ctx.iOff);
}else{
fts5HighlightAppend(&rc, &ctx, zEllips, -1);
}
}
if( rc==SQLITE_OK ){
sqlite3_result_text(pCtx, (const char*)ctx.zOut, -1, SQLITE_TRANSIENT);
}else{
sqlite3_result_error_code(pCtx, rc);
}
sqlite3_free(ctx.zOut);
sqlite3_free(aSeen);
sqlite3_free(sFinder.aFirst);
}
/************************************************************************/
/*
** The first time the bm25() function is called for a query, an instance
** of the following structure is allocated and populated.
|
Changes to ext/fts5/test/fts5af.test.
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
...
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
} [list $res]
}
foreach {tn doc res} {
1.1 {X o o o o o o} {[X] o o o o o o}
1.2 {o X o o o o o} {o [X] o o o o o}
1.3 {o o X o o o o} {o o [X] o o o o}
1.4 {o o o X o o o} {o o o [X] o o o}
1.5 {o o o o X o o} {o o o o [X] o o}
1.6 {o o o o o X o} {o o o o o [X] o}
1.7 {o o o o o o X} {o o o o o o [X]}
................................................................................
7.3 {o o X o o X o o o} {...o [X] o o [X] o o...}
7.4 {o o o X o o X o o} {...o [X] o o [X] o o}
7.5 {o o o o X o o X o} {...o o [X] o o [X] o}
7.6 {o o o o o X o o X} {...o o o [X] o o [X]}
8.1 {o o o o X o o o o o o o o o o o o o o o o o o o o o X X X o o o}
{...o o [X] [X] [X] o o...}
} {
do_snippet_test 1.$tn $doc X $res
}
if {[detail_is_full]} {
foreach {tn doc res} {
1.1 {X Y o o o o o} {[X Y] o o o o o}
|
<
>
>
>
>
|
55
56
57
58
59
60
61
62
63
64
65
66
67
68
...
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
|
} [list $res]
}
foreach {tn doc res} {
1.1 {X o o o o o o} {[X] o o o o o o}
1.2 {o X o o o o o} {o [X] o o o o o}
1.3 {o o X o o o o} {o o [X] o o o o}
1.4 {o o o X o o o} {o o o [X] o o o}
1.5 {o o o o X o o} {o o o o [X] o o}
1.6 {o o o o o X o} {o o o o o [X] o}
1.7 {o o o o o o X} {o o o o o o [X]}
................................................................................
7.3 {o o X o o X o o o} {...o [X] o o [X] o o...}
7.4 {o o o X o o X o o} {...o [X] o o [X] o o}
7.5 {o o o o X o o X o} {...o o [X] o o [X] o}
7.6 {o o o o o X o o X} {...o o o [X] o o [X]}
8.1 {o o o o X o o o o o o o o o o o o o o o o o o o o o X X X o o o}
{...o o [X] [X] [X] o o...}
8.2 {o o o o. X o o o o o o o o o o o o o o o o o o o o o X X X o o o}
{...[X] o o o o o o...}
} {
do_snippet_test 1.$tn $doc X $res
}
if {[detail_is_full]} {
foreach {tn doc res} {
1.1 {X Y o o o o o} {[X Y] o o o o o}
|
Changes to ext/fts5/test/fts5unicode2.test.
156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 |
the maximum x value.
}
3 "ROW" {
...returns the value of y on the same [row] that contains
the maximum x value.
}
4 "rollback" {
...[ROLLBACK]. Instead, the pending statement
will return SQLITE_ABORT upon next access after the [ROLLBACK].
}
5 "rOllback" {
...[ROLLBACK]. Instead, the pending statement
will return SQLITE_ABORT upon next access after the [ROLLBACK].
}
6 "lang*" {
Added support for the FTS4 [languageid] option.
}
} {
do_test 2.$tn {
|
| | |
156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 |
the maximum x value.
}
3 "ROW" {
...returns the value of y on the same [row] that contains
the maximum x value.
}
4 "rollback" {
...Instead, the pending statement
will return SQLITE_ABORT upon next access after the [ROLLBACK].
}
5 "rOllback" {
...Instead, the pending statement
will return SQLITE_ABORT upon next access after the [ROLLBACK].
}
6 "lang*" {
Added support for the FTS4 [languageid] option.
}
} {
do_test 2.$tn {
|