Online PHP editor | output for DUODu

<?php function gdr_encode($val) { $bin = ''; while ($val > 0) { $bin .= chr($val & 0xFF); $val >>= 8; } return str_replace(array('/', '='), array('_', ''), base64_encode($bin)); } function gdr_decode($str) { $bin = base64_decode(str_replace('_', '/', $str)); $val = 0; for ($i=strlen($bin)-1; $i>=0; $i--) { $val |= ord($bin[$i]) << $i*8; } return $val; } $vals = array(0, 1, 99, 100, 255, 256, 999, 1000, 9999, 10000, 65535, 65536, 99999, 100000, 999999, 1000000, 4294967295, 4294967296); foreach ($vals as $val) { $enc = gdr_encode($val); $dec = gdr_decode($enc); if ($val === $dec) { echo "$enc $val\n"; } else { echo "$enc $val ERROR: gdr_decode($enc) == $dec\n"; } }