> This PR continues the efforts from #12632 to speed up case-insensitive string > matching. > > We now tackle case-insensitive comparison of mixed-coder strings, implemented > in `StringLatin1.regionMatchesCI_UTF16` > > Key insights: > > - If the UTF16 code point is also in latin1 range, we can leverage > improvements from 12632 directly by calling > `CharacterDataLatin1.equalsIgnoreCase` > - There are exactly 7 non-latin1 Unicode code points which case fold into the > latin1 range. We can special-case our comparison of these code points by > adding the method `CharacterDataLatin1.latin1CaseFold`. > - To avoid checking of `a == b` twice, this check is lifted out of > `CharacterDataLatin1.equalsIgnoreCase` and the two callers are updated to > check that `a != b` before calling the method. > > For completeness, the RegionMatches test is updated to also compare Turkic > dotted/dotless 'i's against the uppercase ASCII 'I', not just the lowercase > one. Not stricktly related to the purpose of this PR, but it did help catch > a regression introduced in an earlier iteration of the PR. > > To guard against regressions caused by future changes to the set of Unicode > code points folding into latin1, a new test is added to `EqualsIgnoreCase` > which identifies all such code points and verifies they are compared correcty. > > Performance is tested for matching and mismatching cases of selected code > point pairs picked from the ASCII letter, ASCII number, latin1 letter and > non-latin Unicode letter ranges. Results in the first comment below.
Eirik Bjorsnos has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 24 commits: - Merge branch 'master' into regionmatches-mixed-speedup - Inline local variable - latin1CaseFold was moved to CharacterDataLatin1 - Move latin1CaseFold to CharacterDataLatin1 - Improve latin1CaseFold javadocs - Simplify comments - Prefer fast matching by comparing for equality before checking latin1 range - Improve Javadocs of latin1CaseFold - Be consistent in comments - CharacterData.latin1LowerCase was renamed to latin1CaseFold - ... and 14 more: https://git.openjdk.org/jdk/compare/6d30bbe6...2340f8b5 ------------- Changes: https://git.openjdk.org/jdk/pull/12637/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12637&range=01 Stats: 169 lines in 5 files changed: 155 ins; 2 del; 12 mod Patch: https://git.openjdk.org/jdk/pull/12637.diff Fetch: git fetch https://git.openjdk.org/jdk pull/12637/head:pull/12637 PR: https://git.openjdk.org/jdk/pull/12637
