base58_decode. - Decode Flickr shortened URLs

gistfile1.txt

//Given a base58 encoded string, obtain the base 10 number.  
//This is useful for decoding shortened flickr urls. 
function base58_decode( snipcode )
{
    var alphabet = '123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ' ;
    var num = snipcode.length ;
    var decoded = 0 ;
    var multi = 1 ;
    for ( var i = (num-1) ; i >= 0 ; i-- )
    {
        decoded = decoded + multi * alphabet.indexOf( snipcode[i] ) ;
        multi = multi * alphabet.length ;
    }
    return decoded;
}