ext/mbstring: Optimize valid UTF-8 in mb_substr() - #24080
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kamil-tekiela wants to merge 1 commit into
Open
kamil-tekiela wants to merge 1 commit into
kamil-tekiela wants to merge 1 commit into
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kamil-tekiela
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alexdowad and
youkidearitai
as code owners
October 2, 2026 15:58
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This PR adds a fast path for valid UTF-8 strings in
mb_substr. It skips bytes in 256 chunks. The performance improvement is noticeable with longer strings and only ones that are flagged as valid UTF-8.@alexdowad What do you think? Is this worth doing? I haven't got a fuzzer, but I don't anticipate any behavioural changes.