SQLite

#define FTS3_MATCHINFO_NCOL      'c'        /* 1 value */
#define FTS3_MATCHINFO_NDOC      'n'        /* 1 value */
#define FTS3_MATCHINFO_AVGLENGTH 'a'        /* nCol values */
#define FTS3_MATCHINFO_LENGTH    'l'        /* nCol values */
#define FTS3_MATCHINFO_LCS       's'        /* nCol values */
#define FTS3_MATCHINFO_HITS      'x'        /* 3*nCol*nPhrase values */
#define FTS3_MATCHINFO_LHITS     'y'        /* nCol*nPhrase values */
#define FTS3_MATCHINFO_LHITS_BM  'b'        /* nCol*nPhrase values */

/*
** The default value for the second argument to matchinfo(). 
*/
#define FTS3_MATCHINFO_DEFAULT   "pcx"

*/
typedef struct MatchInfo MatchInfo;
struct MatchInfo {
  Fts3Cursor *pCursor;            /* FTS3 Cursor */
  int nCol;                       /* Number of columns in table */
  int nPhrase;                    /* Number of matchable phrases in query */
  sqlite3_int64 nDoc;             /* Number of docs in database */
  char flag;
  u32 *aMatchinfo;                /* Pre-allocated buffer */
};

/*
** An instance of this structure is used to manage a pair of buffers, each
** (nElem * sizeof(u32)) bytes in size. See the MatchinfoBuffer code below
** for details.

*/
static void fts3GetDeltaPosition(char **pp, int *piPos){
  int iVal;
  *pp += fts3GetVarint32(*pp, &iVal);
  *piPos += (iVal-2);
}



/*
** Helper function for fts3ExprIterate() (see below).
*/
static int fts3ExprIterate2(
  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
  int bExcludeEof,
  int *piPhrase,                  /* Pointer to phrase counter */
  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
  void *pCtx                      /* Second argument to pass to callback */
){
  int rc;                         /* Return code */

  if( bExcludeEof && pExpr->bEof ){
    rc = SQLITE_OK;
  }else{
    int eType = pExpr->eType;     /* Type of expression node pExpr */
    if( eType!=FTSQUERY_PHRASE ){
      assert( pExpr->pLeft && pExpr->pRight );
      rc = fts3ExprIterate2(pExpr->pLeft, bExcludeEof, piPhrase, x, pCtx);
      if( rc==SQLITE_OK && eType!=FTSQUERY_NOT ){
        rc = fts3ExprIterate2(pExpr->pRight, bExcludeEof, piPhrase, x, pCtx);
      }
    }else{
      rc = x(pExpr, *piPhrase, pCtx);
      (*piPhrase)++;
    }
  }
  return rc;

** If the callback function returns anything other than SQLITE_OK, 
** the iteration is abandoned and the error code returned immediately.
** Otherwise, SQLITE_OK is returned after a callback has been made for
** all eligible phrase nodes.
*/
static int fts3ExprIterate(
  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
  int bExcludeEof,                /* Include nodes already at EOF */
  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
  void *pCtx                      /* Second argument to pass to callback */
){
  int iPhrase = 0;                /* Variable used as the phrase counter */
  return fts3ExprIterate2(pExpr, bExcludeEof, &iPhrase, x, pCtx);
}

/*
** This is an fts3ExprIterate() callback used while loading the doclists
** for each phrase into Fts3Expr.aDoclist[]/nDoclist. See also
** fts3ExprLoadDoclists().
*/

  Fts3Cursor *pCsr,               /* Fts3 cursor for current query */
  int *pnPhrase,                  /* OUT: Number of phrases in query */
  int *pnToken                    /* OUT: Number of tokens in query */
){
  int rc;                         /* Return Code */
  LoadDoclistCtx sCtx = {0,0,0};  /* Context for fts3ExprIterate() */
  sCtx.pCsr = pCsr;
  rc = fts3ExprIterate(pCsr->pExpr, 0, fts3ExprLoadDoclistsCb, (void *)&sCtx);
  if( pnPhrase ) *pnPhrase = sCtx.nPhrase;
  if( pnToken ) *pnToken = sCtx.nToken;
  return rc;
}

static int fts3ExprPhraseCountCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
  (*(int *)ctx)++;
  UNUSED_PARAMETER(pExpr);
  UNUSED_PARAMETER(iPhrase);
  return SQLITE_OK;
}
static int fts3ExprPhraseCount(Fts3Expr *pExpr){
  int nPhrase = 0;
  (void)fts3ExprIterate(pExpr, 0, fts3ExprPhraseCountCb, (void *)&nPhrase);
  return nPhrase;
}

/*
** Advance the position list iterator specified by the first two 
** arguments so that it points to the first element with a value greater
** than or equal to parameter iNext.

  ** the set of phrases in the expression to populate the aPhrase[] array.
  */
  sIter.pCsr = pCsr;
  sIter.iCol = iCol;
  sIter.nSnippet = nSnippet;
  sIter.nPhrase = nList;
  sIter.iCurrent = -1;
  rc = fts3ExprIterate(pCsr->pExpr, 0, fts3SnippetFindPositions, (void*)&sIter);
  if( rc==SQLITE_OK ){

    /* Set the *pmSeen output variable. */
    for(i=0; i<nList; i++){
      if( sIter.aPhrase[i].pHead ){
        *pmSeen |= (u64)1 << i;
      }

  MatchInfo *p = (MatchInfo *)pCtx;
  
  /* This must be a phrase */
  assert( pExpr->pPhrase );

  if( pExpr->iDocid==p->pCursor->iPrevId ){
    Fts3Table *pTab = (Fts3Table *)p->pCursor->base.pVtab;
    int iStart;
    Fts3Phrase *pPhrase = pExpr->pPhrase;
    char *pIter = pPhrase->doclist.pList;
    int iCol = 0;

    assert( p->flag==FTS3_MATCHINFO_LHITS_BM || p->flag==FTS3_MATCHINFO_LHITS );
    if( p->flag==FTS3_MATCHINFO_LHITS ){
      iStart = iPhrase * p->nCol;
    }else{
      iStart = iPhrase * ((p->nCol + 31) / 32);
    }

    while( 1 ){
      int nHit = fts3ColumnlistCount(&pIter);
      if( (pPhrase->iColumn>=pTab->nColumn || pPhrase->iColumn==iCol) ){
        if( p->flag==FTS3_MATCHINFO_LHITS ){
          p->aMatchinfo[iStart + iCol] = (u32)nHit;
        }else if( nHit ){
          p->aMatchinfo[iStart + (iCol+1)/32] |= (1 << (iCol&0x1F));
        }
      }
      assert( *pIter==0x00 || *pIter==0x01 );
      if( *pIter!=0x01 ) break;
      pIter++;
      pIter += fts3GetVarint32(pIter, &iCol);
    }
  }

   || (cArg==FTS3_MATCHINFO_NCOL)
   || (cArg==FTS3_MATCHINFO_NDOC && pTab->bFts4)
   || (cArg==FTS3_MATCHINFO_AVGLENGTH && pTab->bFts4)
   || (cArg==FTS3_MATCHINFO_LENGTH && pTab->bHasDocsize)
   || (cArg==FTS3_MATCHINFO_LCS)
   || (cArg==FTS3_MATCHINFO_HITS)
   || (cArg==FTS3_MATCHINFO_LHITS)
   || (cArg==FTS3_MATCHINFO_LHITS_BM)
  ){
    return SQLITE_OK;
  }
  sqlite3Fts3ErrMsg(pzErr, "unrecognized matchinfo request: %c", cArg);
  return SQLITE_ERROR;
}

    case FTS3_MATCHINFO_LCS:
      nVal = pInfo->nCol;
      break;

    case FTS3_MATCHINFO_LHITS:
      nVal = pInfo->nCol * pInfo->nPhrase;
      break;

    case FTS3_MATCHINFO_LHITS_BM:
      nVal = pInfo->nPhrase * ((pInfo->nCol + 31) / 32);
      break;

    default:
      assert( cArg==FTS3_MATCHINFO_HITS );
      nVal = pInfo->nCol * pInfo->nPhrase * 3;
      break;
  }

  /* Allocate and populate the array of LcsIterator objects. The array
  ** contains one element for each matchable phrase in the query.
  **/
  aIter = sqlite3_malloc(sizeof(LcsIterator) * pCsr->nPhrase);
  if( !aIter ) return SQLITE_NOMEM;
  memset(aIter, 0, sizeof(LcsIterator) * pCsr->nPhrase);
  (void)fts3ExprIterate(pCsr->pExpr, 0, fts3MatchinfoLcsCb, (void*)aIter);

  for(i=0; i<pInfo->nPhrase; i++){
    LcsIterator *pIter = &aIter[i];
    nToken -= pIter->pExpr->pPhrase->nToken;
    pIter->iPosOffset = nToken;
  }

){
  int rc = SQLITE_OK;
  int i;
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  sqlite3_stmt *pSelect = 0;

  for(i=0; rc==SQLITE_OK && zArg[i]; i++){
    pInfo->flag = zArg[i];
    switch( zArg[i] ){
      case FTS3_MATCHINFO_NPHRASE:
        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nPhrase;
        break;

      case FTS3_MATCHINFO_NCOL:
        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nCol;

      case FTS3_MATCHINFO_LCS:
        rc = fts3ExprLoadDoclists(pCsr, 0, 0);
        if( rc==SQLITE_OK ){
          rc = fts3MatchinfoLcs(pCsr, pInfo);
        }
        break;

      case FTS3_MATCHINFO_LHITS_BM:
      case FTS3_MATCHINFO_LHITS: {
        int nZero = fts3MatchinfoSize(pInfo, zArg[i]) * sizeof(u32);
        memset(pInfo->aMatchinfo, 0, nZero);
        (void)fts3ExprIterate(pCsr->pExpr, 1, fts3ExprLHitsCb, (void*)pInfo);
        break;
      }

      default: {
        Fts3Expr *pExpr;
        assert( zArg[i]==FTS3_MATCHINFO_HITS );
        pExpr = pCsr->pExpr;
        rc = fts3ExprLoadDoclists(pCsr, 0, 0);
        if( rc!=SQLITE_OK ) break;
        if( bGlobal ){
          if( pCsr->pDeferred ){
            rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &pInfo->nDoc, 0);
            if( rc!=SQLITE_OK ) break;
          }
          rc = fts3ExprIterate(pExpr, 0, fts3ExprGlobalHitsCb,(void*)pInfo);
          if( rc!=SQLITE_OK ) break;
        }
        (void)fts3ExprIterate(pExpr, 0, fts3ExprLocalHitsCb,(void*)pInfo);
        break;
      }
    }

    pInfo->aMatchinfo += fts3MatchinfoSize(pInfo, zArg[i]);
  }

    /* Initialize the contents of sCtx.aTerm[] for column iCol. There is 
    ** no way that this operation can fail, so the return code from
    ** fts3ExprIterate() can be discarded.
    */
    sCtx.iCol = iCol;
    sCtx.iTerm = 0;
    (void)fts3ExprIterate(pCsr->pExpr, 0, fts3ExprTermOffsetInit, (void*)&sCtx);

    /* Retreive the text stored in column iCol. If an SQL NULL is stored 
    ** in column iCol, jump immediately to the next iteration of the loop.
    ** If an OOM occurs while retrieving the data (this can happen if SQLite
    ** needs to transform the data from utf-16 to utf-8), return SQLITE_NOMEM 
    ** to the caller. 
    */

  7 "a OR (a AND b)" {
      1 {1 2 1 2 0 1}   2 {1 0 1 0 1 0}   3 {0 1 0 1 1 2}   4 {1 0 1 0 0 1}   
      5 {1 0 1 0 0 1}   6 {1 0 1 0 2 2}   7 {2 1 0 0 0 0}   8 {1 2 1 2 2 1}   
      9 {1 1 1 1 1 3}  10 {1 3 0 0 0 0}
  }

} {
  do_execsql_test 11.1.$tn.1  {
    SELECT rowid, mit(matchinfo(tt, 'y')) FROM tt WHERE tt MATCH $expr
  } $res

  set r2 [list]
  foreach {rowid L} $res {
    lappend r2 $rowid
    set M [list]
    foreach {a b} $L {
      lappend M [expr ($a ? 1 : 0) + ($b ? 2 : 0)]
    }
    lappend r2 $M
  }

  do_execsql_test 11.1.$tn.2  {
    SELECT rowid, mit(matchinfo(tt, 'b')) FROM tt WHERE tt MATCH $expr
  } $r2
  breakpoint

  do_execsql_test 11.1.$tn.2  {
    SELECT rowid, mit(matchinfo(tt, 'b')) FROM tt WHERE tt MATCH $expr
  } $r2
}
set sqlite_fts3_enable_parentheses 0

#---------------------------------------------------------------------------
# Test the 'b' matchinfo flag
#
set sqlite_fts3_enable_parentheses 1
reset_db
db func mit mit

do_test 12.0 {
  set cols [list]
  for {set i 0} {$i < 50} {incr i} { lappend cols "c$i" }
  execsql "CREATE VIRTUAL TABLE tt USING fts3([join $cols ,])"
} {}

do_execsql_test 12.1 {
  INSERT INTO tt (rowid, c4, c45) VALUES(1, 'abc', 'abc');
  SELECT mit(matchinfo(tt, 'b')) FROM tt WHERE tt MATCH 'abc';
} [list [list [expr 1<<4] [expr 1<<(45-32)]]]

set sqlite_fts3_enable_parentheses 0
finish_test

} {
  1 "SELECT matchinfo(content) FROM t2 WHERE t2 MATCH 'history'" matchinfo
  2 "SELECT offsets(content) FROM t2 WHERE t2 MATCH 'history'"   offsets
  3 "SELECT snippet(content) FROM t2 WHERE t2 MATCH 'history'"   snippet
  4 "SELECT optimize(content) FROM t2 WHERE t2 MATCH 'history'"  optimize
}
do_catchsql_test 5.5.1 {
  SELECT matchinfo(t2, 'abcd') FROM t2 WHERE t2 MATCH 'history'
} {1 {unrecognized matchinfo request: d}}

do_execsql_test 5.5 { DROP TABLE t2 }


# Test the snippet() function with 1 to 6 arguments.
# 
do_execsql_test 6.1 {