truncate.php

//truncation
//-------------
$ext = end( explode( '.', $filename ) );
$filename = substr( $filename, 0, -(strlen($ext) + 1) );
$filename = str_replace( '.', '-', $filename );
$filename_shortened = substr( $filename, 0, 70 );
if ( $filename_shortened != $filename ) {
    $filename = preg_replace( '~(-|_)[^\-_]{0,' . floor( strlen($filename) / 2 ) . '}$~', '', $filename_shortened );
}
$filename = trim( $filename, '-_' );
$filename = $filename . '.' . $ext;