fmt.Println(base64.RawStdEncoding.DecodeString("ABCD"))
fmt.Println(base64.RawStdEncoding.DecodeString("ABC"))
fmt.Println(base64.RawStdEncoding.DecodeString("AB"))
fmt.Println(base64.RawStdEncoding.DecodeString("A"))

fmt.Println(base64.RawStdEncoding.DecodeString("ABC="))
fmt.Println(base64.RawStdEncoding.DecodeString("AB=="))

fmt.Println(base64.RawStdEncoding.DecodeString("ABC?"))
fmt.Println(base64.RawStdEncoding.DecodeString("AB?"))

//fixed
[0 16 131]
[0 16] illegal base64 data at input byte 2
[0] illegal base64 data at input byte 1
[] illegal base64 data at input byte 0
[0 16] illegal base64 data at input byte 3
[0] illegal base64 data at input byte 2
[0 16] illegal base64 data at input byte 3
[0] illegal base64 data at input byte 2

//bug
[0 16 131]
[0 16]
[0]
[] illegal base64 data at input byte 0
[] illegal base64 data at input byte 3
[] illegal base64 data at input byte 2
[] illegal base64 data at input byte 3
[] illegal base64 data at input byte 2

// fix bug, if we don't know the code is padding or nopading

To fix a bug, you first need to describe exactly what the bug is and how to reproduce it. Please follow the issue template to do that.

fix the decodeQuantum and DecodedLen
my code link
https://play.golang.org/p/PRDLxcL5qcL

https://play.golang.org/p/rRkszDP-6gS

Please tell us what the problem is. Tell us exactly what you did, exactly what happened, and what you expected to have happen instead. Thanks.

@koggle As far as I can imagine from your pull-request and your codes on play.golang.org, you seems be pointing that RawStdEncoding doesn't handle on padding. But it works as expected. You should use StdEncoding instead of RawStdEncoding.

@mattn @ianlancetaylor @mvdan
Base64 is not a strict encoding format, it is just a storage format, so I think it is compatible in the decoding phase. The padding is only in the encoding process, and the decoding process should ignore the padding.

For example, I have two connections: aa://1234abc and aa://1234abc= This is not generated by me, it is someone else's, in fact, the content is the same. I need StdEncoding and RawStdEncoding for decoding, which doesn't look succinct. When you encounter this kind of aa://1234abc?, RawStdEncoding can't solve it at all.

This issue is still not following the clear steps outlined in the issue template. We're not getting any closer to that format, so I'm going to close this issue for now.

@koggle if you think there is a bug in the base64 package, please open a new issue and follow the template, clearly describing the bug and how to reproduce it.

Do you expect strict encoder? Then please use RawStdEncoding.Strict().DecodeString(s).