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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.
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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.
|
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > < > > > < < > > > > > > > > > > > > > > > > > > | < > | < < > > > > > | < < < | < < < < < < < > > > > > > > > > > > > > | > | | < < > > < < < < < < < < < < < | | | | | | | < > |
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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.
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...
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|
} [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}
|
<
>
>
>
>
|
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...
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|
} [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 {
|