We currently have 2 base64 coders: one in AK, another in LibWeb for a
"forgiving" implementation. ECMA-262 has an upcoming proposal which will
require a third implementation.
Instead, let's use the base64 implementation that is used by Node.js and
recommended by the upcoming proposal. It handles forgiving decoding as
well.
Our users of AK's implementation should be fine with the forgiving
implementation. The AK impl originally had naive forgiving behavior, but
that was removed solely for performance reasons.
Using http://mattmahoney.net/dc/enwik8.zip (100MB unzipped) as a test,
performance of our old home-grown implementations vs. the simdutf
implementation (on Linux x64):
Encode Decode
AK base64 0.226s 0.169s
LibWeb base64 N/A 1.244s
simdutf 0.161s 0.047s
bfc9dc447f