SQLite

*/
static int fts3ExprNearTrim(Fts3Expr *pExpr){
  int rc = SQLITE_OK;
  Fts3Expr *pParent = pExpr->pParent;

  assert( pExpr->eType==FTSQUERY_PHRASE );
  while( rc==SQLITE_OK
   && pParent 
   && pParent->eType==FTSQUERY_NEAR 
   && pParent->pRight==pExpr 
  ){
    /* This expression (pExpr) is the right-hand-side of a NEAR operator. 
    ** Find the expression to the left of the same operator.
    */
    int nNear = pParent->nNear;

    int nHit;
    sqlite3_int64 iCol = 0;
    if( *pCsr==0x01 ){
      pCsr++;
      pCsr += sqlite3Fts3GetVarint(pCsr, &iCol);
    }
    nHit = fts3ColumnlistCount(&pCsr);
    assert( nHit>0 );
    if( isGlobal ){
      aOut[iCol*3+1]++;
    }
    aOut[iCol*3] += nHit;
  }
  pCsr++;
  *pp = pCsr;
}

  ** cannot be found, the second iteration of the loop attempts to locate
  ** a pair of fragments, and so on.
  */
  int nSnippet = 0;               /* Number of fragments in this snippet */
  SnippetFragment aSnippet[4];    /* Maximum of 4 fragments per snippet */
  int nFToken = -1;               /* Number of tokens in each fragment */

  for(nSnippet=1; 1; nSnippet++){

    int iSnip;                    /* Loop counter 0..nSnippet-1 */
    u64 mCovered = 0;             /* Bitmask of phrases covered by snippet */
    u64 mSeen = 0;                /* Bitmask of phrases seen by BestSnippet() */

    if( nToken>=0 ){
      nFToken = (nToken+nSnippet-1) / nSnippet;
    }else{
      nFToken = -1 * nToken;
    }

    for(iSnip=0; iSnip<nSnippet; iSnip++){
      int iBestScore = -1;        /* Best score of columns checked so far */
      int iRead;                  /* Used to iterate through columns */
      SnippetFragment *pFragment = &aSnippet[iSnip];

      memset(pFragment, 0, sizeof(*pFragment));

      mCovered |= pFragment->covered;
    }

    /* If all query phrases seen by fts3BestSnippet() are present in at least
    ** one of the nSnippet snippet fragments, break out of the loop.
    */
    assert( (mCovered&mSeen)==mCovered );
    if( mSeen==mCovered || nSnippet==SizeofArray(aSnippet) ) break;

  }

  assert( nFToken>0 );

  for(i=0; i<nSnippet && rc==SQLITE_OK; i++){
    rc = fts3SnippetText(pCsr, &aSnippet[i], 
        i, (i==nSnippet-1), nFToken, zStart, zEnd, zEllipsis, &res
    );

    sqlite3_tokenizer_cursor *pC; /* Tokenizer cursor */
    int iStart;
    int iEnd;
    int iCurrent;
    const char *zDoc;
    int nDoc;

    /* 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, 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. 
    */

              "%d %d %d %d ", iCol, pTerm-sCtx.aTerm, iStart, iEnd-iStart
          );
          rc = fts3StringAppend(&res, aBuffer, -1);
        }
      }
    }
    if( rc==SQLITE_DONE ){
      rc = SQLITE_CORRUPT;
    }

    pMod->xClose(pC);
    if( rc!=SQLITE_OK ) goto offsets_out;
  }

 offsets_out:

}

proc doPassiveTest {isRestart name sql catchres} {
  if {![info exists ::DO_MALLOC_TEST]} { set ::DO_MALLOC_TEST 1 }

  switch $::DO_MALLOC_TEST {
    0 { # No malloc failures.
      do_test $name [list set {} [uplevel [list catchsql $sql]]] $catchres
      return
    }
    1 { # Simulate transient failures.
      set nRepeat 1
      set zName "transient"
      set nStartLimit 100000
      set nBackup 1

# 2010 January 07
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#*************************************************************************
#
# The tests in this file test the FTS3 auxillary functions offsets(), 
# snippet() and matchinfo() work. At time of writing, running this file 
# provides full coverage of fts3_snippet.c.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# If SQLITE_ENABLE_FTS3 is not defined, omit this file.
ifcapable !fts3 { finish_test ; return }
source $testdir/fts3_common.tcl
source $testdir/malloc_common.tcl

set sqlite_fts3_enable_parentheses 1
set DO_MALLOC_TEST 0

# Transform the list $L to its "normal" form. So that it can be compared to
# another list with the same set of elements using [string compare].
#
proc normalize {L} {
  set ret [list]
  foreach l $L {lappend ret $l}
  return $ret
}

proc do_offsets_test {name expr args} {
  set result [list]
  foreach a $args {
    lappend result [normalize $a]
  }
  do_select_test $name {
    SELECT offsets(ft) FROM ft WHERE ft MATCH $expr
  } $result
}
  
# Document text used by a few tests. Contains the English names of all
# integers between 1 and 300.
#
set numbers [normalize {
  one two three four five six seven eight nine ten eleven twelve thirteen
  fourteen fifteen sixteen seventeen eighteen nineteen twenty twentyone
  twentytwo twentythree twentyfour twentyfive twentysix twentyseven
  twentyeight twentynine thirty thirtyone thirtytwo thirtythree thirtyfour
  thirtyfive thirtysix thirtyseven thirtyeight thirtynine forty fortyone
  fortytwo fortythree fortyfour fortyfive fortysix fortyseven fortyeight
  fortynine fifty fiftyone fiftytwo fiftythree fiftyfour fiftyfive fiftysix
  fiftyseven fiftyeight fiftynine sixty sixtyone sixtytwo sixtythree sixtyfour
  sixtyfive sixtysix sixtyseven sixtyeight sixtynine seventy seventyone
  seventytwo seventythree seventyfour seventyfive seventysix seventyseven
  seventyeight seventynine eighty eightyone eightytwo eightythree eightyfour
  eightyfive eightysix eightyseven eightyeight eightynine ninety ninetyone
  ninetytwo ninetythree ninetyfour ninetyfive ninetysix ninetyseven
  ninetyeight ninetynine onehundred onehundredone onehundredtwo
  onehundredthree onehundredfour onehundredfive onehundredsix onehundredseven
  onehundredeight onehundrednine onehundredten onehundredeleven
  onehundredtwelve onehundredthirteen onehundredfourteen onehundredfifteen
  onehundredsixteen onehundredseventeen onehundredeighteen onehundrednineteen
  onehundredtwenty onehundredtwentyone onehundredtwentytwo
  onehundredtwentythree onehundredtwentyfour onehundredtwentyfive
  onehundredtwentysix onehundredtwentyseven onehundredtwentyeight
  onehundredtwentynine onehundredthirty onehundredthirtyone
  onehundredthirtytwo onehundredthirtythree onehundredthirtyfour
  onehundredthirtyfive onehundredthirtysix onehundredthirtyseven
  onehundredthirtyeight onehundredthirtynine onehundredforty
  onehundredfortyone onehundredfortytwo onehundredfortythree
  onehundredfortyfour onehundredfortyfive onehundredfortysix
  onehundredfortyseven onehundredfortyeight onehundredfortynine
  onehundredfifty onehundredfiftyone onehundredfiftytwo onehundredfiftythree
  onehundredfiftyfour onehundredfiftyfive onehundredfiftysix
  onehundredfiftyseven onehundredfiftyeight onehundredfiftynine
  onehundredsixty onehundredsixtyone onehundredsixtytwo onehundredsixtythree
  onehundredsixtyfour onehundredsixtyfive onehundredsixtysix
  onehundredsixtyseven onehundredsixtyeight onehundredsixtynine
  onehundredseventy onehundredseventyone onehundredseventytwo
  onehundredseventythree onehundredseventyfour onehundredseventyfive
  onehundredseventysix onehundredseventyseven onehundredseventyeight
  onehundredseventynine onehundredeighty onehundredeightyone
  onehundredeightytwo onehundredeightythree onehundredeightyfour
  onehundredeightyfive onehundredeightysix onehundredeightyseven
  onehundredeightyeight onehundredeightynine onehundredninety
  onehundredninetyone onehundredninetytwo onehundredninetythree
  onehundredninetyfour onehundredninetyfive onehundredninetysix
  onehundredninetyseven onehundredninetyeight onehundredninetynine twohundred
  twohundredone twohundredtwo twohundredthree twohundredfour twohundredfive
  twohundredsix twohundredseven twohundredeight twohundrednine twohundredten
  twohundredeleven twohundredtwelve twohundredthirteen twohundredfourteen
  twohundredfifteen twohundredsixteen twohundredseventeen twohundredeighteen
  twohundrednineteen twohundredtwenty twohundredtwentyone twohundredtwentytwo
  twohundredtwentythree twohundredtwentyfour twohundredtwentyfive
  twohundredtwentysix twohundredtwentyseven twohundredtwentyeight
  twohundredtwentynine twohundredthirty twohundredthirtyone
  twohundredthirtytwo twohundredthirtythree twohundredthirtyfour
  twohundredthirtyfive twohundredthirtysix twohundredthirtyseven
  twohundredthirtyeight twohundredthirtynine twohundredforty
  twohundredfortyone twohundredfortytwo twohundredfortythree
  twohundredfortyfour twohundredfortyfive twohundredfortysix
  twohundredfortyseven twohundredfortyeight twohundredfortynine
  twohundredfifty twohundredfiftyone twohundredfiftytwo twohundredfiftythree
  twohundredfiftyfour twohundredfiftyfive twohundredfiftysix
  twohundredfiftyseven twohundredfiftyeight twohundredfiftynine
  twohundredsixty twohundredsixtyone twohundredsixtytwo twohundredsixtythree
  twohundredsixtyfour twohundredsixtyfive twohundredsixtysix
  twohundredsixtyseven twohundredsixtyeight twohundredsixtynine
  twohundredseventy twohundredseventyone twohundredseventytwo
  twohundredseventythree twohundredseventyfour twohundredseventyfive
  twohundredseventysix twohundredseventyseven twohundredseventyeight
  twohundredseventynine twohundredeighty twohundredeightyone
  twohundredeightytwo twohundredeightythree twohundredeightyfour
  twohundredeightyfive twohundredeightysix twohundredeightyseven
  twohundredeightyeight twohundredeightynine twohundredninety
  twohundredninetyone twohundredninetytwo twohundredninetythree
  twohundredninetyfour twohundredninetyfive twohundredninetysix
  twohundredninetyseven twohundredninetyeight twohundredninetynine
  threehundred
}]

foreach {DO_MALLOC_TEST enc} {
  0 utf8
  1 utf8
  1 utf16
} {

  db close
  file delete -force test.db
  sqlite3 db test.db
  db eval "PRAGMA encoding = \"$enc\""

  # Set variable $T to the test name prefix for this iteration of the loop.
  #
  set T "fts3snippet-$enc"

  ##########################################################################
  # Test the offset function.
  #
  do_test $T.1.1 {
    execsql {
      CREATE VIRTUAL TABLE ft USING fts3;
      INSERT INTO ft VALUES('xxx xxx xxx xxx');
    }
  } {}



  do_offsets_test $T.1.2 {xxx} {0 0 0 3 0 0 4 3 0 0 8 3 0 0 12 3}
  do_offsets_test $T.1.3 {"xxx xxx"} {
      0 0  0 3     0 0  4 3     0 1  4 3     0 0  8 3 
      0 1  8 3     0 1 12 3
  }

  do_offsets_test $T.1.4 {"xxx xxx" xxx} {

      0 0  0 3     0 2  0 3     0 0  4 3     0 1  4 3 


      0 2  4 3     0 0  8 3     0 1  8 3     0 2  8 3 

      0 1 12 3     0 2 12 3

  }
  do_offsets_test $T.1.5 {xxx "xxx xxx"} {



      0 0  0 3     0 1  0 3     0 0  4 3     0 1  4 3 



      0 2  4 3     0 0  8 3     0 1  8 3     0 2  8 3 
      0 0 12 3     0 2 12 3
  }


  do_test $T.9.1 {
    set v1 [lrange $numbers 0 99]
    execsql {
      DROP TABLE IF EXISTS ft;
      CREATE VIRTUAL TABLE ft USING fts3(a, b);
      INSERT INTO ft VALUES($v1, $numbers);
      INSERT INTO ft VALUES($v1, NULL);
    }
  } {}

  set off [string first "twohundred " $numbers]

  do_offsets_test $T.9.1 {twohundred} [list 1 0 $off 10]

  set off [string first "onehundred " $numbers]
  do_offsets_test $T.9.2 {onehundred} \
    [list 0 0 $off 10 1 0 $off 10] [list 0 0 $off 10]

  # Test a corruption case:
  execsql { UPDATE ft_content SET c1b = 'hello world' WHERE c1b = $numbers }
  do_error_test $T.9.3 {
    SELECT offsets(ft) FROM ft WHERE ft MATCH 'onehundred'
  } {database disk image is malformed}
  
  ##########################################################################
  # Test the snippet function.
  #
  proc do_snippet_test {name expr iCol nTok args} {
    set res [list]
    foreach a $args { lappend res [string trim $a] }
    do_select_test $name {
      SELECT snippet(ft,'{','}','...',$iCol,$nTok) FROM ft WHERE ft MATCH $expr
    } $res
  }
  do_test $T.2.1 {
    execsql {
      DROP TABLE IF EXISTS ft;
      CREATE VIRTUAL TABLE ft USING fts3;
      INSERT INTO ft VALUES('one two three four five six seven eight nine ten');
    }
  } {}
  do_snippet_test $T.2.2  one    0 5 "{one} two three four five..."
  do_snippet_test $T.2.3  two    0 5 "one {two} three four five..."
  do_snippet_test $T.2.4  three  0 5 "one two {three} four five..."
  do_snippet_test $T.2.5  four   0 5 "...two three {four} five six..."
  do_snippet_test $T.2.6  five   0 5 "...three four {five} six seven..."
  do_snippet_test $T.2.7  six    0 5 "...four five {six} seven eight..."
  do_snippet_test $T.2.8  seven  0 5 "...five six {seven} eight nine..."
  do_snippet_test $T.2.9  eight  0 5 "...six seven {eight} nine ten"
  do_snippet_test $T.2.10 nine   0 5 "...six seven eight {nine} ten"
  do_snippet_test $T.2.11 ten    0 5 "...six seven eight nine {ten}"
  
  do_test $T.3.1 {
    execsql {
      INSERT INTO ft VALUES(
           'one two three four five '
        || 'six seven eight nine ten '
        || 'eleven twelve thirteen fourteen fifteen '
        || 'sixteen seventeen eighteen nineteen twenty '
        || 'one two three four five '
        || 'six seven eight nine ten '
        || 'eleven twelve thirteen fourteen fifteen '
        || 'sixteen seventeen eighteen nineteen twenty'
      );
    }
  } {}
  
  do_snippet_test $T.3.2 {one nine} 0 5 {
     {one} two three...eight {nine} ten
  } {
     {one} two three...eight {nine} ten...
  }
  
  do_snippet_test $T.3.3 {one nine} 0 -5 {
     {one} two three four five...six seven eight {nine} ten
  } {
     {one} two three four five...seven eight {nine} ten eleven...
  }
  do_snippet_test $T.3.3 {one nineteen} 0 -5 {
     ...eighteen {nineteen} twenty {one} two...
  }
  do_snippet_test $T.3.4 {two nineteen} 0 -5 {
     ...eighteen {nineteen} twenty one {two}...
  }
  do_snippet_test $T.3.5 {three nineteen} 0 -5 {
     ...{nineteen} twenty one two {three}...
  }
  
  do_snippet_test $T.3.6 {four nineteen} 0 -5 {
     ...two three {four} five six...seventeen eighteen {nineteen} twenty one...
  }
  do_snippet_test $T.3.7 {four NEAR nineteen} 0 -5 {
     ...seventeen eighteen {nineteen} twenty one...two three {four} five six...
  }
  
  do_snippet_test $T.3.8 {four nineteen} 0 5 {
     ...three {four} five...eighteen {nineteen} twenty...
  }
  do_snippet_test $T.3.9 {four NEAR nineteen} 0 5 {
     ...eighteen {nineteen} twenty...three {four} five...
  }
  do_snippet_test $T.3.10 {four NEAR nineteen} 0 -5 {
     ...seventeen eighteen {nineteen} twenty one...two three {four} five six...
  }
  do_snippet_test $T.3.11 {four NOT (nineteen twentyone)} 0 5 {
     ...two three {four} five six...
  } {
     ...two three {four} five six...
  }
  do_snippet_test $T.3.12 {four OR nineteen NEAR twentyone} 0 5 {
     ...two three {four} five six...
  } {
     ...two three {four} five six...
  }
  
  do_test $T.5.1 {
    execsql {
      DROP TABLE IF EXISTS ft;
      CREATE VIRTUAL TABLE ft USING fts3(a, b, c);
      INSERT INTO ft VALUES(
        'one two three four five', 
        'four five six seven eight', 
        'seven eight nine ten eleven'
      );
    }
  } {}
  
  do_snippet_test $T.5.2 {five} -1 3 {...three four {five}}
  do_snippet_test $T.5.3 {five}  0 3 {...three four {five}}
  do_snippet_test $T.5.4 {five}  1 3 {four {five} six...}
  do_snippet_test $T.5.5 {five}  2 3 {seven eight nine...}
  
  do_test $T.5.6 {
    execsql { UPDATE ft SET b = NULL }
  } {}
  
  do_snippet_test $T.5.7  {five} -1 3 {...three four {five}}
  do_snippet_test $T.5.8  {five}  0 3 {...three four {five}}
  do_snippet_test $T.5.9  {five}  1 3 {}
  do_snippet_test $T.5.10 {five}  2 3 {seven eight nine...}
  
  do_snippet_test $T.5.11 {one "seven eight nine"} -1 -3 {
    {one} two three...{seven} {eight} {nine}...
  }

  do_test $T.6.1 {
    execsql {
      DROP TABLE IF EXISTS ft;
      CREATE VIRTUAL TABLE ft USING fts3(x);
      INSERT INTO ft VALUES($numbers);
    }
  } {}
  do_snippet_test $T.6.2 {
    one fifty onehundred onehundredfifty twohundredfifty threehundred
  } -1 4 {
    {one}...{fifty}...{onehundred}...{onehundredfifty}...
  }
  do_snippet_test $T.6.3 {
    one fifty onehundred onehundredfifty twohundredfifty threehundred
  } -1 -4 {
    {one} two three four...fortyeight fortynine {fifty} fiftyone...ninetyeight ninetynine {onehundred} onehundredone...onehundredfortyeight onehundredfortynine {onehundredfifty} onehundredfiftyone...
  }

  do_test $T.7.1 {
    execsql {
      BEGIN;
        DROP TABLE IF EXISTS ft;
        CREATE VIRTUAL TABLE ft USING fts3(x);
    }
    set testresults [list]
    for {set i 1} {$i < 150} {incr i} {
      set commas [string repeat , $i]
      execsql {INSERT INTO ft VALUES('one' || $commas || 'two')}
      lappend testresults "{one}$commas{two}"
    }
    execsql COMMIT
  } {}
  do_snippet_test $T.7.2 {one two} -1 3 {*}$testresults
  
  ##########################################################################
  # Test the matchinfo function.
  #
  proc mit {blob} {
    set scan(littleEndian) i*
    set scan(bigEndian) I*
    binary scan $blob $scan($::tcl_platform(byteOrder)) r
    return $r
  }
  db func mit mit
  proc do_matchinfo_test {name expr args} {
    set res [list]
    foreach a $args { lappend res [normalize $a] }
    do_select_test $name {
      SELECT mit(matchinfo(ft)) FROM ft WHERE ft MATCH $expr
    } $res
  }
  do_test $T.4.1 {
    set ten {one two three four five six seven eight nine ten}
    execsql {
      DROP TABLE IF EXISTS ft;
      CREATE VIRTUAL TABLE ft USING fts3;
      INSERT INTO ft VALUES($ten);
      INSERT INTO ft VALUES($ten || ' ' || $ten);
    }
  } {}
  
  do_matchinfo_test $T.4.2 "one" {1 1  1 3 2} {1 1  2 3 2}
  do_matchinfo_test $T.4.3 "one NEAR/3 ten" {2 1  1 1 1 1 1 1}
  do_matchinfo_test $T.4.4 "five NEAR/4 ten" \
    {2 1  1 3 2  1 3 2} {2 1  2 3 2  2 3 2}
  do_matchinfo_test $T.4.5 "six NEAR/3 ten NEAR/3 two" \
    {3 1  1 1 1  1 1 1  1 1 1}
  do_matchinfo_test $T.4.6 "five NEAR/4 ten NEAR/3 two" \
    {3 1  2 2 1  1 1 1  1 1 1}

  do_test $T.8.1 {
    execsql {
      DROP TABLE IF EXISTS ft;
      CREATE VIRTUAL TABLE ft USING fts3(x, y);
    }
    foreach n {1 2 3} {
      set v1 [lrange $numbers 0 [expr $n*100]]
      set v2 [string trim [string repeat "$numbers " $n]]
      set docid [expr $n * 1000000]
      execsql { INSERT INTO ft(docid, x, y) VALUES($docid, $v1, $v2) }
    }
  } {}
  do_matchinfo_test $T.8.2 {two*}     \
    { 1 2    1   105 3   101 606 3}   \
    { 1 2    3   105 3   202 606 3}   \
    { 1 2    101 105 3   303 606 3}

  do_matchinfo_test $T.8.4 {"one* two*"}  \
    { 1 2    1 5 3   2 12 3}              \
    { 1 2    2 5 3   4 12 3}              \
    { 1 2    2 5 3   6 12 3}

  do_matchinfo_test $T.8.5 {twohundredfifty}  \
    { 1 2    0 1 1   1 6 3}                   \
    { 1 2    0 1 1   2 6 3}                   \
    { 1 2    1 1 1   3 6 3}

  do_matchinfo_test $T.8.6 {"threehundred one"} \
    { 1 2    0 0 0   1 3 2}                     \
    { 1 2    0 0 0   2 3 2}

  do_matchinfo_test $T.8.7 {one OR fivehundred} \
    { 2 2    1 3 3   1 6 3   0 0 0   0 0 0 }    \
    { 2 2    1 3 3   2 6 3   0 0 0   0 0 0 }    \
    { 2 2    1 3 3   3 6 3   0 0 0   0 0 0 }

  do_matchinfo_test $T.8.8 {two OR "threehundred one"} \
    { 2 2    1 3 3   1 6 3   0 0 0   0 3 2 }           \
    { 2 2    1 3 3   2 6 3   0 0 0   1 3 2 }           \
    { 2 2    1 3 3   3 6 3   0 0 0   2 3 2 }

  do_select_test $T.8.9 {
    SELECT mit(matchinfo(ft)), mit(matchinfo(ft))
    FROM ft WHERE ft MATCH 'two OR "threehundred one"' 
  } [normalize {
    {2 2 1 3 3 1 6 3 0 0 0 0 3 2}
    {2 2 1 3 3 1 6 3 0 0 0 0 3 2}
    {2 2 1 3 3 2 6 3 0 0 0 1 3 2}
    {2 2 1 3 3 2 6 3 0 0 0 1 3 2}
    {2 2 1 3 3 3 6 3 0 0 0 2 3 2}          
    {2 2 1 3 3 3 6 3 0 0 0 2 3 2}
  }]
}

set sqlite_fts3_enable_parentheses 0
finish_test