protected function normalizeWhitespace($sText)
{
$sText = str_replace(["\t", "\r\n", "\n"], ' ', $sText);
# using multiple str_replace has proven to be twice as fast that regexp on big strings
$iCount = 0;
do {
$sText = str_replace(' ', ' ', $sText, $iCount);
} while ($iCount > 0);
return trim($sText);
}