Unique Url offers you a simple way to create unique (pseudo-random) strings from numbers (e.g. primary keys) and convert them back. The technique is based on linear feedback shift registers.
You need to include one file to make use of the unique url class.
include 'kevinkub\UniqueUrl\UniqueUrl.php';
use \kevinkub\UniqueUrl\UniqueUrl as UniqueUrl;
It is required to setup a string length for the encoding process. Please note that a length of ten is the maximum on 64-bit systems. The calculations will take a little longer (o(n^2)) the longer the string gets.
// new UniqueUrl(int stringLength[, int recursionFactor])
$uniqueUrl = new UniqueUrl(4[, 111]);
The class comes with a default recursion of n^2 * 111. However if you want to have a custom "rythm" in your codes you should change this value. A lower value will give you results, that are closer to each other (AA, AB, AC, ...). A higher value gives you more spreaded results but takes more computation time. However 111 has been a good value in all of my tests.
The primary goal of this class is to encode numbers (e.g. primary keys from your dbs)
to strings and back. To do so, simply call encode().
$uniqueUrl->encode(12); // returns (for example) 'A0-j'
To decode a string back to the number which was encoded use the decode() function.
$uniqueUrl->decode('A0-j'); // returns 12;
Depending on the string length you choose, the numbers you can encode are limited too. You can encode any number between 0 and 64^n - 1. PHP seems to limit the combinations to 64^10. I have not investigated into this any further, but if you need to use this algorithm on numbers larger than 1,1529215e18-1 ... man you have other problems.