Library does not decode unpadded base64 about base64pp

[matheusgomes28]

Hi @cleanerx, thanks for submitting the issue.

This library was intended to just provide encoding/decoding of valid Base64 strings. Although fixing the string eyJuYW1lIjoiSm9obiBEb2UifQ with padding is quite trivial, it's not really considered "valid" base64 for the missing padding.

I'm not going to close this yet, as I do want to see what other libraries currently do with said string. I'm happy to reproduce behaviour in OpenSSL, so I'll spend some time seeing how they handle invalid padded strings there.

[matheusgomes28]

@cleanerx OpenSSL also fails to decode the string you mentioned: https://godbolt.org/z/sKebhj4h5 (uncomment the padding and you can see it works).

Although I'm not a massive fan of changing the behaviour of the public API and doing things the user may not expect, I'll add some tasks here to provide this extra functionality to the library. I figured that, even though OpenSSL and other libs don't do this, it may be expected from users for the library to pad these base64 strings.

[matheusgomes28]

Closed with #90