excerpt and highlight

<?php
function excerpt($text, $query)
{
  //words
  $words = join('|', explode(' ', preg_quote($query)));

  //lookahead/behind assertions ensures cut between words
  $s = '\s\x00-/:-@\[-`{-~'; //character set for start/end of words
  preg_match_all('#(?<=['.$s.']).{1,50}(('.$words.').{1,50})+(?=['.$s.'])#uis', $text, $matches, PREG_SET_ORDER);

  //delimiter between occurences
  $results = array();
  foreach($matches as $line) {
      $results[] = htmlspecialchars($line[0], 0, 'UTF-8');
  }
  $result = join(' <b>(...)</b> ', $results);

  //highlight
  $result = preg_replace('#'.$words.'#iu', "<span class=\"azul\">\$0</span>", $result);

  // 

  return $result;
}