Convert sorted data arrays to the Eytzinger order

[hsivonen]

The Eytzinger order improved things for Gecko's HTML parser. Data tables that are currently only searched by binary search should probably be converted to the Eytzinger order.

[jrmuizel]

Not sure if you saw this or not but here's rust implementation of Eytzinger-arranged arrays: https://github.com/jonhoo/ordsearch

[hsivonen]

Thank you. I hadn't seen it.

[hsivonen]

I'll leave this open in case someone else really cares enough to implement and measure, but

• The hot part of EUC-KR has to remain in its present order.
• Re-sorting the cold parts of EUC-KR and GBK probably doesn't matter much as they are cold parts.
• The label lookup is probably fast enough as-is not to merit active effort on it.