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Overview
Comment:Update the spellfix virtual table extension so that an explicit "top = ?" constraint works even if there is also a "distance < ?" or "distance <= ?" constraint.
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Files: files | file ages | folders
SHA1: 0888838371608558f31d5bcb5fed1c8861aa52c1
User & Date: dan 2015-08-05 15:29:32
Context
2015-08-05
19:35
Add tests for the matchinfo-like test function. Fix problems found in test and fts5 code by doing so. check-in: 9e3aafe4 user: dan tags: trunk
15:29
Update the spellfix virtual table extension so that an explicit "top = ?" constraint works even if there is also a "distance < ?" or "distance <= ?" constraint. check-in: 08888383 user: dan tags: trunk
08:01
Fix some problems in test code detected by cppcheck. check-in: c9ff4ca4 user: dan tags: trunk
Changes
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Changes to ext/misc/spellfix.c.

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};

/* Fuzzy-search cursor object */
struct spellfix1_cursor {
  sqlite3_vtab_cursor base;    /* Base class - must be first */
  spellfix1_vtab *pVTab;       /* The table to which this cursor belongs */
  char *zPattern;              /* rhs of MATCH clause */

  int nRow;                    /* Number of rows of content */
  int nAlloc;                  /* Number of allocated rows */
  int iRow;                    /* Current row of content */
  int iLang;                   /* Value of the langid= constraint */
  int iTop;                    /* Value of the top= constraint */
  int iScope;                  /* Value of the scope= constraint */
  int nSearch;                 /* Number of vocabulary items checked */
................................................................................
  spellfix1ResetCursor(pCur);
  spellfix1ResizeCursor(pCur, 0);
  sqlite3_free(pCur->zPattern);
  sqlite3_free(pCur);
  return SQLITE_OK;
}

/*
** Search for terms of these forms:
**
**   (A)    word MATCH $str
**   (B)    langid == $langid
**   (C)    top = $top
**   (D)    scope = $scope
**   (E)    distance < $distance
**   (F)    distance <= $distance
**   (G)    rowid = $rowid
**
** The plan number is a bit mask formed with these bits:
**
**   0x01   (A) is found
**   0x02   (B) is found
**   0x04   (C) is found
**   0x08   (D) is found
**   0x10   (E) is found
**   0x20   (F) is found
**   0x40   (G) is found
**
** filter.argv[*] values contains $str, $langid, $top, $scope and $rowid
** if specified and in that order.
*/
static int spellfix1BestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
  int iPlan = 0;
  int iLangTerm = -1;
................................................................................
  int i;
  const struct sqlite3_index_constraint *pConstraint;
  pConstraint = pIdxInfo->aConstraint;
  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
    if( pConstraint->usable==0 ) continue;

    /* Terms of the form:  word MATCH $str */
    if( (iPlan & 1)==0 
     && pConstraint->iColumn==SPELLFIX_COL_WORD
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_MATCH
    ){
      iPlan |= 1;
      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
      pIdxInfo->aConstraintUsage[i].omit = 1;
    }

    /* Terms of the form:  langid = $langid  */
    if( (iPlan & 2)==0
     && pConstraint->iColumn==SPELLFIX_COL_LANGID
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= 2;
      iLangTerm = i;
    }

    /* Terms of the form:  top = $top */
    if( (iPlan & 4)==0
     && pConstraint->iColumn==SPELLFIX_COL_TOP
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= 4;
      iTopTerm = i;
    }

    /* Terms of the form:  scope = $scope */
    if( (iPlan & 8)==0
     && pConstraint->iColumn==SPELLFIX_COL_SCOPE
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= 8;
      iScopeTerm = i;
    }

    /* Terms of the form:  distance < $dist or distance <= $dist */
    if( (iPlan & (16|32))==0
     && pConstraint->iColumn==SPELLFIX_COL_DISTANCE
     && (pConstraint->op==SQLITE_INDEX_CONSTRAINT_LT
          || pConstraint->op==SQLITE_INDEX_CONSTRAINT_LE)
    ){
      iPlan |= pConstraint->op==SQLITE_INDEX_CONSTRAINT_LT ? 16 : 32;




      iDistTerm = i;
    }

    /* Terms of the form:  distance < $dist or distance <= $dist */
    if( (iPlan & 64)==0
     && pConstraint->iColumn<0
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= 64;
      iRowidTerm = i;
    }
  }
  if( iPlan&1 ){
    int idx = 2;
    pIdxInfo->idxNum = iPlan;
    if( pIdxInfo->nOrderBy==1
     && pIdxInfo->aOrderBy[0].iColumn==SPELLFIX_COL_SCORE
     && pIdxInfo->aOrderBy[0].desc==0
    ){
      pIdxInfo->orderByConsumed = 1;  /* Default order by iScore */
    }
    if( iPlan&2 ){
      pIdxInfo->aConstraintUsage[iLangTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iLangTerm].omit = 1;
    }
    if( iPlan&4 ){
      pIdxInfo->aConstraintUsage[iTopTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iTopTerm].omit = 1;
    }
    if( iPlan&8 ){
      pIdxInfo->aConstraintUsage[iScopeTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iScopeTerm].omit = 1;
    }
    if( iPlan&(16|32) ){
      pIdxInfo->aConstraintUsage[iDistTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iDistTerm].omit = 1;
    }
    pIdxInfo->estimatedCost = 1e5;
  }else if( (iPlan & 64) ){
    pIdxInfo->idxNum = 64;
    pIdxInfo->aConstraintUsage[iRowidTerm].argvIndex = 1;
    pIdxInfo->aConstraintUsage[iRowidTerm].omit = 1;
    pIdxInfo->estimatedCost = 5;
  }else{
    pIdxInfo->idxNum = 0;
    pIdxInfo->estimatedCost = 1e50;
  }
................................................................................
      iDist = editdist1(p->zPattern, zK1, 0);
    }
    if( iDist<0 ){
      p->rc = SQLITE_NOMEM;
      break;
    }
    pCur->nSearch++;
    iScore = spellfix1Score(iDist,iRank);








    if( p->iMaxDist>=0 ){
      if( iDist>p->iMaxDist ) continue;
      if( pCur->nRow>=pCur->nAlloc-1 ){
        spellfix1ResizeCursor(pCur, pCur->nAlloc*2 + 10);
        if( pCur->a==0 ) break;
      }
      idx = pCur->nRow;



    }else if( pCur->nRow<pCur->nAlloc ){
      idx = pCur->nRow;
    }else if( iScore<iWorst ){
      idx = idxWorst;
      sqlite3_free(pCur->a[idx].zWord);
    }else{
      continue;
    }

    pCur->a[idx].zWord = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 1));
    if( pCur->a[idx].zWord==0 ){
      p->rc = SQLITE_NOMEM;
      break;
    }
    pCur->a[idx].iRowid = sqlite3_column_int64(pStmt, 0);
    pCur->a[idx].iRank = iRank;
................................................................................

/*
** This version of the xFilter method work if the MATCH term is present
** and we are doing a scan.
*/
static int spellfix1FilterForMatch(
  spellfix1_cursor *pCur,
  int idxNum,
  int argc,
  sqlite3_value **argv
){

  const unsigned char *zMatchThis;   /* RHS of the MATCH operator */
  EditDist3FromString *pMatchStr3 = 0; /* zMatchThis as an editdist string */
  char *zPattern;                    /* Transliteration of zMatchThis */
  int nPattern;                      /* Length of zPattern */
  int iLimit = 20;                   /* Max number of rows of output */
  int iScope = 3;                    /* Use this many characters of zClass */
  int iLang = 0;                     /* Language code */
................................................................................
}

/*
** This version of xFilter handles a full-table scan case
*/
static int spellfix1FilterForFullScan(
  spellfix1_cursor *pCur,
  int idxNum,
  int argc,
  sqlite3_value **argv
){
  int rc = SQLITE_OK;

  char *zSql;
  spellfix1_vtab *pVTab = pCur->pVTab;
  spellfix1ResetCursor(pCur);
  assert( idxNum==0 || idxNum==64 );
  zSql = sqlite3_mprintf(
     "SELECT word, rank, NULL, langid, id FROM \"%w\".\"%w_vocab\"%s",
     pVTab->zDbName, pVTab->zTableName,
................................................................................
static int spellfix1Filter(
  sqlite3_vtab_cursor *cur, 
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  spellfix1_cursor *pCur = (spellfix1_cursor *)cur;
  int rc;

  if( idxNum & 1 ){
    rc = spellfix1FilterForMatch(pCur, idxNum, argc, argv);
  }else{
    rc = spellfix1FilterForFullScan(pCur, idxNum, argc, argv);
  }
  return rc;
}


/*
** Advance a cursor to its next row of output







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};

/* Fuzzy-search cursor object */
struct spellfix1_cursor {
  sqlite3_vtab_cursor base;    /* Base class - must be first */
  spellfix1_vtab *pVTab;       /* The table to which this cursor belongs */
  char *zPattern;              /* rhs of MATCH clause */
  int idxNum;                  /* idxNum value passed to xFilter() */
  int nRow;                    /* Number of rows of content */
  int nAlloc;                  /* Number of allocated rows */
  int iRow;                    /* Current row of content */
  int iLang;                   /* Value of the langid= constraint */
  int iTop;                    /* Value of the top= constraint */
  int iScope;                  /* Value of the scope= constraint */
  int nSearch;                 /* Number of vocabulary items checked */
................................................................................
  spellfix1ResetCursor(pCur);
  spellfix1ResizeCursor(pCur, 0);
  sqlite3_free(pCur->zPattern);
  sqlite3_free(pCur);
  return SQLITE_OK;
}

#define SPELLFIX_IDXNUM_MATCH  0x01         /* word MATCH $str */
#define SPELLFIX_IDXNUM_LANGID 0x02         /* langid == $langid */
#define SPELLFIX_IDXNUM_TOP    0x04         /* top = $top */
#define SPELLFIX_IDXNUM_SCOPE  0x08         /* scope = $scope */
#define SPELLFIX_IDXNUM_DISTLT 0x10         /* distance < $distance */
#define SPELLFIX_IDXNUM_DISTLE 0x20         /* distance <= $distance */
#define SPELLFIX_IDXNUM_ROWID  0x40         /* rowid = $rowid */
#define SPELLFIX_IDXNUM_DIST   (0x10|0x20)  /* DISTLT and DISTLE */

/*
**
** The plan number is a bitmask of the SPELLFIX_IDXNUM_* values defined
** above.







**
** filter.argv[*] values contains $str, $langid, $top, $scope and $rowid
** if specified and in that order.
*/
static int spellfix1BestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
  int iPlan = 0;
  int iLangTerm = -1;
................................................................................
  int i;
  const struct sqlite3_index_constraint *pConstraint;
  pConstraint = pIdxInfo->aConstraint;
  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
    if( pConstraint->usable==0 ) continue;

    /* Terms of the form:  word MATCH $str */
    if( (iPlan & SPELLFIX_IDXNUM_MATCH)==0 
     && pConstraint->iColumn==SPELLFIX_COL_WORD
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_MATCH
    ){
      iPlan |= SPELLFIX_IDXNUM_MATCH;
      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
      pIdxInfo->aConstraintUsage[i].omit = 1;
    }

    /* Terms of the form:  langid = $langid  */
    if( (iPlan & SPELLFIX_IDXNUM_LANGID)==0
     && pConstraint->iColumn==SPELLFIX_COL_LANGID
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= SPELLFIX_IDXNUM_LANGID;
      iLangTerm = i;
    }

    /* Terms of the form:  top = $top */
    if( (iPlan & SPELLFIX_IDXNUM_TOP)==0
     && pConstraint->iColumn==SPELLFIX_COL_TOP
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= SPELLFIX_IDXNUM_TOP;
      iTopTerm = i;
    }

    /* Terms of the form:  scope = $scope */
    if( (iPlan & SPELLFIX_IDXNUM_SCOPE)==0
     && pConstraint->iColumn==SPELLFIX_COL_SCOPE
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= SPELLFIX_IDXNUM_SCOPE;
      iScopeTerm = i;
    }

    /* Terms of the form:  distance < $dist or distance <= $dist */
    if( (iPlan & SPELLFIX_IDXNUM_DIST)==0
     && pConstraint->iColumn==SPELLFIX_COL_DISTANCE
     && (pConstraint->op==SQLITE_INDEX_CONSTRAINT_LT
          || pConstraint->op==SQLITE_INDEX_CONSTRAINT_LE)
    ){
      if( pConstraint->op==SQLITE_INDEX_CONSTRAINT_LT ){
        iPlan |= SPELLFIX_IDXNUM_DISTLT;
      }else{
        iPlan |= SPELLFIX_IDXNUM_DISTLE;
      }
      iDistTerm = i;
    }

    /* Terms of the form:  distance < $dist or distance <= $dist */
    if( (iPlan & SPELLFIX_IDXNUM_ROWID)==0
     && pConstraint->iColumn<0
     && pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      iPlan |= SPELLFIX_IDXNUM_ROWID;
      iRowidTerm = i;
    }
  }
  if( iPlan&SPELLFIX_IDXNUM_MATCH ){
    int idx = 2;
    pIdxInfo->idxNum = iPlan;
    if( pIdxInfo->nOrderBy==1
     && pIdxInfo->aOrderBy[0].iColumn==SPELLFIX_COL_SCORE
     && pIdxInfo->aOrderBy[0].desc==0
    ){
      pIdxInfo->orderByConsumed = 1;  /* Default order by iScore */
    }
    if( iPlan&SPELLFIX_IDXNUM_LANGID ){
      pIdxInfo->aConstraintUsage[iLangTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iLangTerm].omit = 1;
    }
    if( iPlan&SPELLFIX_IDXNUM_TOP ){
      pIdxInfo->aConstraintUsage[iTopTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iTopTerm].omit = 1;
    }
    if( iPlan&SPELLFIX_IDXNUM_SCOPE ){
      pIdxInfo->aConstraintUsage[iScopeTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iScopeTerm].omit = 1;
    }
    if( iPlan&SPELLFIX_IDXNUM_DIST ){
      pIdxInfo->aConstraintUsage[iDistTerm].argvIndex = idx++;
      pIdxInfo->aConstraintUsage[iDistTerm].omit = 1;
    }
    pIdxInfo->estimatedCost = 1e5;
  }else if( (iPlan & SPELLFIX_IDXNUM_ROWID) ){
    pIdxInfo->idxNum = SPELLFIX_IDXNUM_ROWID;
    pIdxInfo->aConstraintUsage[iRowidTerm].argvIndex = 1;
    pIdxInfo->aConstraintUsage[iRowidTerm].omit = 1;
    pIdxInfo->estimatedCost = 5;
  }else{
    pIdxInfo->idxNum = 0;
    pIdxInfo->estimatedCost = 1e50;
  }
................................................................................
      iDist = editdist1(p->zPattern, zK1, 0);
    }
    if( iDist<0 ){
      p->rc = SQLITE_NOMEM;
      break;
    }
    pCur->nSearch++;

    
    /* If there is a "distance < $dist" or "distance <= $dist" constraint,
    ** check if this row meets it. If not, jump back up to the top of the
    ** loop to process the next row. Otherwise, if the row does match the
    ** distance constraint, check if the pCur->a[] array is already full.
    ** If it is and no explicit "top = ?" constraint was present in the
    ** query, grow the array to ensure there is room for the new entry. */
    assert( (p->iMaxDist>=0)==((pCur->idxNum & SPELLFIX_IDXNUM_DIST) ? 1 : 0) );
    if( p->iMaxDist>=0 ){
      if( iDist>p->iMaxDist ) continue;
      if( pCur->nRow>=pCur->nAlloc && (pCur->idxNum & SPELLFIX_IDXNUM_TOP)==0 ){
        spellfix1ResizeCursor(pCur, pCur->nAlloc*2 + 10);
        if( pCur->a==0 ) break;
      }

    }

    iScore = spellfix1Score(iDist,iRank);
    if( pCur->nRow<pCur->nAlloc ){
      idx = pCur->nRow;
    }else if( iScore<iWorst ){
      idx = idxWorst;
      sqlite3_free(pCur->a[idx].zWord);
    }else{
      continue;
    }

    pCur->a[idx].zWord = sqlite3_mprintf("%s", sqlite3_column_text(pStmt, 1));
    if( pCur->a[idx].zWord==0 ){
      p->rc = SQLITE_NOMEM;
      break;
    }
    pCur->a[idx].iRowid = sqlite3_column_int64(pStmt, 0);
    pCur->a[idx].iRank = iRank;
................................................................................

/*
** This version of the xFilter method work if the MATCH term is present
** and we are doing a scan.
*/
static int spellfix1FilterForMatch(
  spellfix1_cursor *pCur,

  int argc,
  sqlite3_value **argv
){
  int idxNum = pCur->idxNum;
  const unsigned char *zMatchThis;   /* RHS of the MATCH operator */
  EditDist3FromString *pMatchStr3 = 0; /* zMatchThis as an editdist string */
  char *zPattern;                    /* Transliteration of zMatchThis */
  int nPattern;                      /* Length of zPattern */
  int iLimit = 20;                   /* Max number of rows of output */
  int iScope = 3;                    /* Use this many characters of zClass */
  int iLang = 0;                     /* Language code */
................................................................................
}

/*
** This version of xFilter handles a full-table scan case
*/
static int spellfix1FilterForFullScan(
  spellfix1_cursor *pCur,

  int argc,
  sqlite3_value **argv
){
  int rc = SQLITE_OK;
  int idxNum = pCur->idxNum;
  char *zSql;
  spellfix1_vtab *pVTab = pCur->pVTab;
  spellfix1ResetCursor(pCur);
  assert( idxNum==0 || idxNum==64 );
  zSql = sqlite3_mprintf(
     "SELECT word, rank, NULL, langid, id FROM \"%w\".\"%w_vocab\"%s",
     pVTab->zDbName, pVTab->zTableName,
................................................................................
static int spellfix1Filter(
  sqlite3_vtab_cursor *cur, 
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  spellfix1_cursor *pCur = (spellfix1_cursor *)cur;
  int rc;
  pCur->idxNum = idxNum;
  if( idxNum & 1 ){
    rc = spellfix1FilterForMatch(pCur, argc, argv);
  }else{
    rc = spellfix1FilterForFullScan(pCur, argc, argv);
  }
  return rc;
}


/*
** Advance a cursor to its next row of output