Add SliceUtf8.toTitleCase()

[wendigo]

this is based on the logic of the toLower and toUpper case

[wendigo]

@martint @dain ptal

[wendigo]

@martint PTAL

[PPL-TBSK]

@wendigo @martint any news please ?

[dain]

Looks good to me

[wendigo]

@dain I've pushed new implementation. PTAL

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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Reviewing files that changed from the base of the PR and between a0818bd and 53d58d9.

📒 Files selected for processing (2)

• src/main/java/io/airlift/slice/SliceUtf8.java
• src/test/java/io/airlift/slice/TestSliceUtf8.java

🚧 Files skipped from review as they are similar to previous changes (2)

• src/main/java/io/airlift/slice/SliceUtf8.java
• src/test/java/io/airlift/slice/TestSliceUtf8.java

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📝 Walkthrough

Walkthrough

This pull request adds UTF-8 title-casing support to SliceUtf8. It introduces a TITLE_CODE_POINTS lookup table in static initialization, adds public toTitleCase methods for Slice and byte-array ranges, and implements a code-point-based transformation that title-cases the first cased code point of each whitespace-delimited word and lowercases subsequent code points. Invalid UTF-8 sequences are copied verbatim and do not reset word-start state. Output allocation is lazy; unchanged input is returned as a wrapped view. Tests validate behavior, invalid-UTF-8 handling, and no-op wrapping.

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[coderabbitai]

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

src/test/java/io/airlift/slice/TestSliceUtf8.java (1)

756-775: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Consider adding test coverage for toTitleCase with invalid bytes at start and middle positions.

The assertions for toLowerCase/toUpperCase test invalid sequences at three positions: end only, start + end ("FOO"), and surrounding ("FOO" + invalid + "BAR"). However, toTitleCase only covers the end position. This matters for title-casing because the start-of-word state should persist across invalid sequences.

🧪 Suggested additional assertions

+        // invalid sequence at start followed by text should not start a new word
+        assertThat(toTitleCase(wrappedBuffer(concat(invalidSequence, new byte[] {'F', 'O', 'O'}))))
+                .isEqualTo(wrappedBuffer(concat(invalidSequence, new byte[] {'F', 'o', 'o'})));
+
+        // invalid sequence in middle should not start a new word
+        assertThat(toTitleCase(wrappedBuffer(concat(new byte[] {'F', 'O', 'O'}, invalidSequence, new byte[] {'B', 'A', 'R'}))))
+                .isEqualTo(wrappedBuffer(concat(new byte[] {'F', 'o', 'o'}, invalidSequence, new byte[] {'b', 'a', 'r'})));

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Configuration used: Organization UI

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📥 Commits

Reviewing files that changed from the base of the PR and between f72c712 and d8d6530.

📒 Files selected for processing (2)

• src/main/java/io/airlift/slice/SliceUtf8.java
• src/test/java/io/airlift/slice/TestSliceUtf8.java

[dain]

Looks good to me, but maybe squash to one commit