$text = '.'x400;
$summary = substr($text, 0, 500);
print(length($summary), "\n");    # 400

$text = '.'x500;
$summary = substr($text, 0, 500);
print(length($summary), "\n");    # 500

$text = '.'x600;
$summary = substr($text, 0, 500);
print(length($summary), "\n");    # 500