Converting between different number bases

[JoeBrewer]

Hi

I have a number base (in base 62) which is represented like this:

php Code:

$base = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

Can anyone help me with a function that converts from decimal (base 10) to this new base please ? I have tried base_convert, but that only works with bases up to 36.

Any help would be much appriciated.

Thanks,
Joe

[Installer]

On a platter:

$base_str = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
// Can be any string of any length (unique characters work best, of course).
$n_base = strlen($base_str);
$num = (37 * pow($n_base, 3)) + (36 * pow($n_base, 2)) + (35 * pow($n_base, 1)) + (34 * pow($n_base, 0)); 
// B is the 37th character, A the 36th, z the 35th, and y the 34th, so the result should be BAzy.
$converted = dec2base($num, $n_base, $base_str);
echo 'Base 10: ' . $num . '<br />';
echo 'Base ' . $n_base . ': ' . $converted;

function dec2base($dec, $base, $str)
{
    $exp = 0;
    while ($dec >= pow($base, $exp)) {
        $exp++;
    }
    for (--$exp, $ret = ''; $exp >= 0; $exp--) {
        $pow = pow($base, $exp);
        $pos = floor($dec / $pow);
        $dec = $dec - ($pos * $pow);
        $ret .= $str[$pos];
    }
    return $ret;
}

[JoeBrewer]

Thanks for your help. It's much appriciated.

Joe