<i18n dev> RFR: 8302871: Speed up StringLatin1.regionMatchesCI [v7]

[David Holmes]

On Tue, 21 Feb 2023 23:28:52 GMT, Eirik Bjorsnos <duke at openjdk.org> wrote:

>> More to the point, ASCII was obviously **designed** to allow you to uppercase a lower case letter with a single instruction, so "the book" might have been a draft standard before they scrubbed out the interesting history!
>
> Thanks Martin, I will from now on envision a stack of dusty punch cards with carefully scribbled notes on the back, barely held together with a dry and cracked rubber band.
> 
> More to the point: Do you have an opinion on the appropriate level of documentation / comments for this kind of 'tricky' code? My goal is that future maintainers should not get scared by the code and help them understand why it became what it is.

There are still some books on this :) but from wikipedia:
> during May 1963 the CCITT Working Party on the New Telegraph Alphabet proposed to assign lowercase characters to sticks[[a]](https://en.wikipedia.org/wiki/ASCII#cite_note-NB_Stick-15)[[14]](https://en.wikipedia.org/wiki/ASCII#cite_note-Bemer_1980_Inside-14) 6 and 7,[[15]](https://en.wikipedia.org/wiki/ASCII#cite_note-CCITT_1963-16) and [International Organization for Standardization](https://en.wikipedia.org/wiki/International_Organization_for_Standardization) TC 97 SC 2 voted during October to incorporate the change into its draft standard.[[16]](https://en.wikipedia.org/wiki/ASCII#cite_note-ISO_1963-17) The X3.2.4 task group voted its approval for the change to ASCII at its May 1963 meeting.[[17]](https://en.wikipedia.org/wiki/ASCII#cite_note-18) **Locating the lowercase letters in sticks[[a]](https://en.wikipedia.org/wiki/ASCII#cite_note-NB_Stick-15)[[14]](https://en.wikipedia.org/wiki/ASCII#cite_note-Bemer_1980_Inside-14) 6 and 7 caused the characters to differ in bit pattern f
 rom the upper case by a single bit, which simplified [case-insensitive](https://en.wikipedia.org/wiki/Case-insensitive) character matching and the construction of keyboards and printers.**

Hence the simplicity of the shift key :)

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PR: https://git.openjdk.org/jdk/pull/12632