MIME4J-283 DecoderUtil performance fix

[hirthwork]

DecoderUtil currently uses the following regex pattern for rfc2047-encoded words: 
"(.*?)=\\?(.+?)\\?(\\w)\\?(.*?)\\?="
First capturing group (.*?) is a very expensive regular expression causing next pattern node evaluation on every input character. Because of this decoding of 4 KB input (To: field with 40-80 recipients) takes up to 200ms on modern CPUs.

At the same time, this capturing group used only to store separator text between encoded words. Proposed patch reuses existing tailIndex for separator text extraction and same input decoding now takes only 1-2ms.

[chibenwa]

Thank you very much for this great contribution that unlocks significant performance improvement.

Let's wait a couple other approuvals before merging.

Cheers,

Benoit Tellier

[hirthwork]

Bump.
Any chance to have this merged? I've prefer to use mime4j version from master instead of locally patched version

[chibenwa]

I am going to merge it now

[chibenwa]

Hi,

This pull request has just been merged.

Thank you again for your dedication toward the James project.

One very last thing: I don't have write access to this repository, hence I can not close this issue. Wouldn't you mind doing it for me? It would avoid me annoying the Apache INFRA team with such simple concerns.

Thanks again,

Cheers,

Benoit