SQLite

  int nDoclist,                   /* Length of aDoclist in bytes */
  char **ppIter,                  /* IN/OUT: Iterator pointer */
  sqlite3_int64 *piDocid,         /* IN/OUT: Docid pointer */
  int *pnList,                    /* IN/OUT: List length pointer */
  u8 *pbEof                       /* OUT: End-of-file flag */
){
  char *p = *ppIter;


  assert( nDoclist>0 );
  assert( *pbEof==0 );
  assert( p || *piDocid==0 );
  assert( !p || (p>aDoclist && p<&aDoclist[nDoclist]) );

  if( p==0 ){
    sqlite3_int64 iDocid = 0;
    char *pNext = 0;
    char *pDocid = aDoclist;
    char *pEnd = &aDoclist[nDoclist];
    int iMul = 1;




    while( pDocid<pEnd ){
      sqlite3_int64 iDelta;
      pDocid += sqlite3Fts3GetVarint(pDocid, &iDelta);
      iDocid += (iMul * iDelta);
      pNext = pDocid;
      fts3PoslistCopy(0, &pDocid);
      while( pDocid<pEnd && *pDocid==0 ) pDocid++;
      iMul = (bDescIdx ? -1 : 1);
    }

    *pnList = pEnd - pNext;
    *ppIter = pNext;
    *piDocid = iDocid;
  }else{
    int iMul = (bDescIdx ? -1 : 1);
    sqlite3_int64 iDelta;
    fts3GetReverseVarint(&p, aDoclist, &iDelta);
    *piDocid -= (iMul * iDelta);

    if( p==aDoclist ){
      *pbEof = 1;
    }else{

#
# $MATCHINFO may be any expression accepted by the FTS4 MATCH operator, 
# except that the "<column-name>:token" syntax is not supported. Tcl list
# commands are used to tokenize the expression. Any parenthesis must appear
# either as separate list elements, or as the first (for opening) or last
# (for closing) character of a list element. i.e. the expression "(a OR b)c"
# will not be parsed correctly, but "( a OR b) c" will.
#
# Available OPTIONS are:
#
#     -deferred TOKENLIST
#
# If the "deferred" option is supplied, it is passed a list of tokens that
# are deferred by FTS and result in the relevant matchinfo() stats being an
# approximation. 
#
set sqlite_fts3_enable_parentheses 1
proc do_fts3query_test {tn args} {

  set nArg [llength $args]
  if {$nArg < 2 || ($nArg % 2)} {
    set cmd do_fts3query_test
    error "wrong # args: should be \"$cmd ?-deferred LIST? TABLE MATCHEXPR\""
  }
  set tbl   [lindex $args [expr $nArg-2]]
  set match [lindex $args [expr $nArg-1]]
  set deferred [list]

  foreach {k v} [lrange $args 0 [expr $nArg-3]] {
    switch -- $k {
      -deferred {
        set deferred $v
      }
      default {
        error "bad option \"$k\": must be -deferred"
      }
    }
  }

  get_near_results $tbl $match $deferred aMatchinfo


  set matchinfo_asc [list]
  foreach docid [lsort -integer -incr [array names aMatchinfo]] {
    lappend matchinfo_asc $docid $aMatchinfo($docid)
  }
  set matchinfo_desc [list]
  foreach docid [lsort -integer -decr [array names aMatchinfo]] {

    if {[string match -nocase near/* $a]} { set a [string range $a 5 end] }
    lappend out $a
    lappend out $b
  }
  return $out
}

proc get_single_near_results {tbl expr deferred arrayvar nullvar} {
  upvar $arrayvar aMatchinfo
  upvar $nullvar nullentry
  catch {array unset aMatchinfo}

  set expr [fix_near_expr $expr]

  # Calculate the expected results using [fts3_near_match]. The following

    foreach c $counts($key) {
      if {$c>0} { incr nDoc($iPhrase,$iCol) 1 }
      incr nHit($iPhrase,$iCol) $c
      incr iPhrase
    }
  }

  if {[llength $deferred] && [llength $expr]==1} {
    set phrase [lindex $expr 0]
    set rewritten [list]
    set partial 0
    foreach tok $phrase {
      if {[lsearch $deferred $tok]>=0} {
        lappend rewritten *
      } else {
        lappend rewritten $tok
        set partial 1
      }
    }
    if {$partial==0} {
      set tblsize [db one "SELECT count(*) FROM $tbl"]
      for {set iCol 0} {$iCol < $nCol} {incr iCol} {
        set nHit(0,$iCol) $tblsize
        set nDoc(0,$iCol) $tblsize
      }
    } elseif {$rewritten != $phrase} {
      while {[lindex $rewritten end] == "*"} {
        set rewritten [lrange $rewritten 0 end-1]
      }
      while {[lindex $rewritten 0] == "*"} {
        set rewritten [lrange $rewritten 1 end]
      }
      get_single_near_results $tbl [list $rewritten] {} aRewrite nullentry
      foreach docid [array names hits] {
        set aMatchinfo($docid) $aRewrite($docid)
      }
      return
    }
  }

    if {$c == "("} {incr iBracket}
    if {$c == ")"} {incr iBracket -1}
  }

  return [expr ($iBracket==0 && $i==$nExpr)]
}

proc get_near_results {tbl expr deferred arrayvar {nullvar ""}} {
  upvar $arrayvar aMatchinfo
  if {$nullvar != ""} { upvar $nullvar nullentry }

  set expr [string trim $expr]
  while { [matching_brackets $expr] } {
    set expr [string trim [string range $expr 1 end-1]]
  }

        if {$c == ")"} { incr iBracket -1 }
      }
    }
  }
  if {$iBracket!=0} { error "mismatched brackets in: $expr" }

  if {[info exists opidx]==0} {
    get_single_near_results $tbl $expr $deferred aMatchinfo nullentry
  } else {
    set eLeft  [lrange $expr 0 [expr $opidx-1]]
    set eRight [lrange $expr [expr $opidx+1] end]

    get_near_results $tbl $eLeft  $deferred aLeft  nullleft
    get_near_results $tbl $eRight $deferred aRight nullright

    switch -- [lindex $expr $opidx] {
      "NOT" {
        foreach hit [array names aLeft] {
          if {0==[info exists aRight($hit)]} {
            set aMatchinfo($hit) $aLeft($hit)
          }

#--------------------------------------------------------------------------
# Some test cases involving deferred tokens.
#
proc make_token_deferrable {tbl token} {
  set nRow [db one "SELECT count(*) FROM $tbl"]
  set pgsz [db one "PRAGMA page_size"]


  execsql BEGIN
  for {set i 0} {$i < ($nRow * $pgsz * 1.2)/100} {incr i} {
    set doc [string repeat "$token " 100]
    execsql "INSERT INTO $tbl VALUES(\$doc)"
  }
  execsql "INSERT INTO $tbl VALUES('aaaaaaa ${token}aaaaa')"
  execsql COMMIT

    INSERT INTO t1(docid, x) VALUES(4, 'a c e g i k');
    INSERT INTO t1(docid, x) VALUES(5, 'a d g j');
    INSERT INTO t1(docid, x) VALUES(6, 'c a b');
  }

  make_token_deferrable t1 c


  foreach {tn2 expr} {
    1     {a OR c}
  } {
    do_fts3query_test 3.$tn.2.$tn2 t1 $expr
  }


  execsql { 
    UPDATE t1_segments 
    SET block = zeroblob(length(block)) 
    WHERE length(block)>10000 AND 0
  }
  foreach {tn2 expr def} {
    1     {a NEAR c}            {}
    2     {a AND c}             c
    3     {"a c"}               c
    4     {"c a"}               c
    5     {"a c" NEAR/1 g}      {}
    6     {"a c" NEAR/0 g}      {}
  } {
    do_fts3query_test 3.$tn.2.$tn2 -deferred $def t1 $expr
  }
}

#--------------------------------------------------------------------------
#
foreach {tn create} {
  1    "fts4(x, y)"
  2    "fts4(x, y, order=DESC)"
} {
  catchsql { DROP TABLE t1 }
  execsql  "CREATE VIRTUAL TABLE t1 USING $create"

  foreach {x y} {
    {one two five four five} {}
    {} {one two five four five}
    {one two} {five four five}
  } {
    execsql {INSERT INTO t1 VALUES($x, $y)}
  }

  foreach {tn2 expr} {
    1     {one AND five}
    2     {one NEAR five}
    3     {one NEAR/1 five}
    4     {one NEAR/2 five}
    5     {one NEAR/3 five}
  } {
    do_fts3query_test 4.$tn.2.$tn2 t1 $expr
  }
}

set sqlite_fts3_enable_parentheses $sfep
finish_test

  fts3atoken.test fts3b.test fts3c.test fts3cov.test fts3d.test
  fts3defer.test fts3defer2.test fts3e.test fts3expr.test fts3expr2.test 
  fts3near.test fts3query.test fts3shared.test fts3snippet.test 
  fts3sort.test

  fts3fault.test fts3malloc.test fts3matchinfo.test

  fts3aux1.test fts3comp1.test fts3auto.test
}


lappend ::testsuitelist xxx
#-------------------------------------------------------------------------
# Define the coverage related test suites:
#