Update Units.php

[david-build]

1. Added = sign for base64 url encoding
2. Shorter crc16 with same result.

[ingria]

Thanks for the PR.

I’ll look into your crc16 implementation, but I cannot understand what’s your idea behind the padding sign replacement (= to -).

Could you please elaborate?

[david-build]

Hi, dear! About sign equals:

While I wrote the packing and checking CRC16 function for converting RAW to Human Friendly TON address, I did tests on thousands of addresses. And I met somewhere that after base64encode the address got "=" at the end. Therefore, I decided to replace = in my code as well.

I think, just in case, it is better to have it than not. Since it has no effect for the worse.

[ingria]

Unfortunately it doesn't work this way. The RFC standard for base64url defines = as optional, and - as 62nd alphabet symbol.

If we replace = with -, it would be impossible to decode an encoded string, because parser wouldn't know for sure where is the padding symbol and where is the 62th symbol.

Also TON addresses are specifically designed not to have = at the end, so if you see = in the address, it means that the address is invalid.

[david-build]

Good, thanks! I'm change it too in our side.
Create one other pull request only with crc32?