Decode Base64 string

[cymplecy]

I've finally got round to making a Base64 decoder using the information from Base64 Decode Algorithm | Base64 Algorithm | Learn | Base64

It's very naive and takes 22 seconds to decode a 100x100 encoded image on my computer!

So, if anyone fancies improving it (no JS of course) I'd be really grateful

The final image should look like this (it's a tile of part of an earthnullschool.net wind map) but the decoder must decode the simple ones as well in order to be compliant

Username=cymplecy&ProjectName=base64

[edit Originally it was taking 300 secs but I'd made a mistake with encoding the data in the 1st place - all OK now - output bytes should be 40,000 long if processing the tile image]

[cymplecy]

And I don't need it myself at the moment but if someone fancies writing an encoder to go with it that would be very nice

[dardoro]

With conversion 4 => 3 bytes "unrolled" as a single expression.
X mod 2^n - extract n low bits
X / 2^n - drop n low bits
X * 2 ^n - shift left n bit

Username=dardoro&ProjectName=base64%20decode

[cymplecy]

Wow
Actually does it in 679ms on mine

Now going thru it to make see how you've done it [edit - Done that - great idea not to have to convert to binary and then back again ]

Thank you very much

[dardoro]

Compiled map makes it twice as fast on my computer

[cymplecy]

I've made a few cosmetic variable name changes, added padding if needed and made a custom reporter out of it.

I've left the map un-compiled at the moment as I've sometimes had issues with compiled blocks

Thank you once again

Username=cymplecy&ProjectName=base64Decode

[dardoro]

Although the new version

is twice as fast as the previous one, it still pales in comparison to JS

[cymplecy]

Because the complied version doesn't yield while its running, I'm not using it on large images

But I've added it as seperate block for anyone who wants to use it