SQLite

  const u8 *p = *pa;
  const u8 *pEnd = &p[n];         /* One byte past end of position list */
  u8 prev = 0;

  while( iCol!=iCurrent ){
    /* Advance pointer p until it points to pEnd or an 0x01 byte that is
    ** not part of a varint */
    while( (prev & 0x80) || *p!=0x01 ){
      prev = *p++;
      if( p==pEnd ) return 0;
    }
    *pa = p++;
    p += fts5GetVarint32(p, iCurrent);
  }

  /* Advance pointer p until it points to pEnd or an 0x01 byte that is
  ** not part of a varint */
  assert( (prev & 0x80)==0 );
  while( p<pEnd && ((prev & 0x80) || *p!=0x01) ){
    prev = *p++;
  }
  return p - (*pa);
}

static int fts5ExprExtractColset (
  Fts5ExprColset *pColset,        /* Colset to filter on */

static int fts5ExprNearTest(
  int *pRc,
  Fts5Expr *pExpr,                /* Expression that pNear is a part of */
  Fts5ExprNode *pNode             /* The "NEAR" node (FTS5_STRING) */
){
  Fts5ExprNearset *pNear = pNode->pNear;
  int rc = *pRc;





































  int i;

  /* Check that each phrase in the nearset matches the current row.
  ** Populate the pPhrase->poslist buffers at the same time. If any
  ** phrase is not a match, break out of the loop early.  */
  for(i=0; rc==SQLITE_OK && i<pNear->nPhrase; i++){
    Fts5ExprPhrase *pPhrase = pNear->apPhrase[i];
    if( pPhrase->nTerm>1 || pNear->pColset ){
      int bMatch = 0;
      rc = fts5ExprPhraseIsMatch(pExpr, pNear->pColset, pPhrase, &bMatch);
      if( bMatch==0 ) break;
    }else{
      rc = sqlite3Fts5IterPoslistBuffer(
          pPhrase->aTerm[0].pIter, &pPhrase->poslist
      );
    }
  }

  *pRc = rc;
  if( i==pNear->nPhrase && (i==1 || fts5ExprNearIsMatch(pRc, pNear)) ){
    return 1;

  }

  return 0;
}

static int fts5ExprTokenTest(
  Fts5Expr *pExpr,                /* Expression that pNear is a part of */

  }else{
    if( iLhs>iRhs ) return -1;
    return (iLhs < iRhs);
  }
}

static void fts5ExprSetEof(Fts5ExprNode *pNode){

  int i;
  pNode->bEof = 1;
  for(i=0; i<pNode->nChild; i++){
    fts5ExprSetEof(pNode->apChild[i]);

  }
}

static void fts5ExprNodeZeroPoslist(Fts5ExprNode *pNode){
  if( pNode->eType==FTS5_STRING || pNode->eType==FTS5_TERM ){
    Fts5ExprNearset *pNear = pNode->pNear;
    int i;

Fts5ExprColset *sqlite3Fts5ParseColset(
  Fts5Parse *pParse,              /* Store SQLITE_NOMEM here if required */
  Fts5ExprColset *pColset,        /* Existing colset object */
  Fts5Token *p
){
  Fts5ExprColset *pRet = 0;


  int iCol;
  char *z;                        /* Dequoted copy of token p */

  z = sqlite3Fts5Strndup(&pParse->rc, p->p, p->n);
  if( pParse->rc==SQLITE_OK ){
    Fts5Config *pConfig = pParse->pConfig;
    sqlite3Fts5Dequote(z);
    for(iCol=0; iCol<pConfig->nCol; iCol++){
      if( 0==sqlite3_stricmp(pConfig->azCol[iCol], z) ) break;

    }

    if( iCol==pConfig->nCol ){
      sqlite3Fts5ParseError(pParse, "no such column: %s", z);


    }else{




      pRet = fts5ParseColset(pParse, pColset, iCol);
    }
    sqlite3_free(z);
  }

  if( pRet==0 ){
    assert( pParse->rc!=SQLITE_OK );

    sqlite3_free(pColset);
  }

  return pRet;
}

void sqlite3Fts5ParseSetColset(

        zRet = fts5PrintfAppend(zRet, "%s%s", iTerm==0?"":" ", zTerm);
      }

      if( zRet ) zRet = fts5PrintfAppend(zRet, "}");
      if( zRet==0 ) return 0;
    }



  }else{
    char const *zOp = 0;
    int i;
    switch( pExpr->eType ){
      case FTS5_AND: zOp = "AND"; break;
      case FTS5_NOT: zOp = "NOT"; break;
      default: 

do_execsql_test 1.0 {
  CREATE VIRTUAL TABLE tt USING fts5(a, b, c, d, e, f);
} {}

fts5_aux_test_functions db

proc matchdata {expr tbl collist {order ASC}} {

  set cols ""
  foreach e $collist {
    append cols ", '$e'"
  }

  set tclexpr [db one [subst -novar {
    SELECT fts5_expr_tcl(
      $expr, 'nearset $cols -pc ::pc' [set cols]
    )
  }]]
  set res [list]

  db eval "SELECT rowid, * FROM $tbl ORDER BY rowid $order" x {
    set cols [list]
    foreach col $x(*) {
      if {$col != "rowid"} { lappend cols $x($col) }
    }
    # set cols [list $a $b $c $d $e $f]
    set ::pc 0
    set rowdata [eval $tclexpr]
    if {$rowdata != ""} { lappend res $x(rowid) $rowdata }
  }

  set res
}

proc do_auto_test {tn tbl cols expr} { 
  foreach order {asc desc} {
    set res [matchdata $expr $tbl $cols $order]
    set testname "$tn.[string range $order 0 0].rows=[expr [llength $res]/2]"

    set ::autotest_expr $expr
    do_execsql_test $testname [subst -novar {
      SELECT rowid, fts5_test_poslist([set tbl]) FROM [set tbl] 
      WHERE [set tbl] MATCH $::autotest_expr ORDER BY rowid [set order]
    }] $res
  }


}

#-------------------------------------------------------------------------

    A.3 { {a b f} : x }
    A.4 { {f a b} : x }
    A.5 { {f a b} : x y }
    A.6 { {f a b} : x + y }
    A.7 { {c a b} : x + c }
    A.8 { {c d} : "l m" }
    A.9 { {c e} : "l m" }
    A.10 { {a b c a b c a b c f f e} : "l m" }

    B.1 { a NOT b }
    B.2 { a NOT a:b }
    B.3 { a OR (b AND c) }
    B.4 { a OR (b AND {a b c}:c) }
    B.5 { a OR "b c" }
    B.6 { a OR b OR c }

    C.1 { a OR (b AND "b c") }
    C.2 { a OR (b AND "z c") }
  } {
    do_auto_test 3.$fold.$tn tt {a b c d e f} $expr
  }
}

proc replace_elems {list args} {
  set ret $list
  foreach {idx elem} $args {
    set ret [lreplace $ret $idx $idx $elem]
  }
  set ret
}

#-------------------------------------------------------------------------
#
set bigdoc [string trim [string repeat "a " 1000]]
do_test 4.0 {
  set a [replace_elems $bigdoc  50 x  950 x]
  set b [replace_elems $bigdoc  20 y   21 x  887 x 888 y]
  set c [replace_elems $bigdoc   1 z  444 z  789 z]
  execsql {
    CREATE VIRTUAL TABLE yy USING fts5(c1, c2, c3);
    INSERT INTO yy(rowid, c1, c2, c3) VALUES(-56789, $a, $b, $c);
    INSERT INTO yy(rowid, c1, c2, c3) VALUES(250, $a, $b, $c);
  }
} {}

foreach {tn expr} {
  1 x    
  2 y    
  3 z

  4 {c1 : x} 5 {c2 : x} 6 {c3 : x}
  7 {c1 : y} 8 {c2 : y} 9 {c3 : y}
  10 {c1 : z} 11 {c2 : z} 12 {c3 : z}


} {
breakpoint
  do_auto_test 4.$tn yy {c1 c2 c3} $expr
}



finish_test

  faultsim_restore_and_reopen
  db eval { SELECT * FROM vv }
} -body {
  db eval { SELECT * FROM vv }
} -test {
  faultsim_test_result {0 {a 1 1 b 1 1}} 
}

#-------------------------------------------------------------------------
# OOM in multi-column token query.
#
reset_db
do_execsql_test 13.0 {
  CREATE VIRTUAL TABLE ft USING fts5(x, y, z);
  INSERT INTO ft(ft, rank) VALUES('pgsz', 32);
  INSERT INTO ft VALUES(
      'x x x x x x x x x x x x x x x x',
      'y y y y y y y y y y y y y y y y',
      'z z z z z z z z x x x x x x x x'
  );
  INSERT INTO ft SELECT * FROM ft;
  INSERT INTO ft SELECT * FROM ft;
  INSERT INTO ft SELECT * FROM ft;
  INSERT INTO ft SELECT * FROM ft;
}
faultsim_save_and_close
do_faultsim_test 13.1 -faults oom-t* -prep {
  faultsim_restore_and_reopen
  db eval { SELECT * FROM ft }
} -body {
  db eval { SELECT rowid FROM ft WHERE ft MATCH '{x z}: x' }
} -test {
  faultsim_test_result {0 {1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16}}
}


finish_test