koi8fix

// Remove or replace non-koi8 characters from string
function fixkoi8($string, $unknownChar = '?') {
  // Single quotes
  $search[]  = chr(226).chr(128).chr(152);
  $replace[] = "'";
  $search[]  = chr(226).chr(128).chr(153);
  $replace[] = "'";
  // Double quotes, 2 variants
  $search[]  = chr(226).chr(128).chr(156);
  $replace[] = '"';
  $search[]  = chr(226).chr(128).chr(157);
  $replace[] = '"';
  // Long dash
  $search[]  = chr(226).chr(128).chr(147);
  $replace[] = '--';
  // Very long dash
  $search[]  = chr(226).chr(128).chr(148);
  $replace[] = '---';
  // Wildcard
  $search[]  = chr(226).chr(128).chr(162);
  $replace[] = '*';
  // Middle dot
  $search[]  = chr(194).chr(183);
  $replace[] = '*';
  // Three dots
  $search[]  = chr(226).chr(128).chr(166);
  $replace[] = '...';
  // Numero
  $search[] = chr(226).chr(132).chr(150);
  $replace[] = 'No';
  // Apply Replacements
  $string = str_replace($search, $replace, $string);
  // Remove any non-ASCII Characters
  $string = preg_replace('/[^\x01-\x7FА-Яа-яё]/u', $unknownChar, $string);
  return $string;
}