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Faster String#dump, #scrub and #codepoints on ASCII-heavy strings - #9975
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headius
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Thanks for the review changes!
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Ports a few of @FletcherDares' string fast paths from CRuby:
String#dump: copy runs of safe ASCII in bulk (Improve performance ofString#dumpusing lookup table ruby/ruby#17287, still open upstream)String#scrub: skip the ASCII run after a valid multibyte char (Improve performance of String#scrub by skipping ASCII runs withsearch_nonasciiruby/ruby#16359)String#codepoints: ASCII bytes skip the codepoint decode (Improve performance ofString#codepointswith ASCII hot path in multi-byte strings. ruby/ruby#16991)I also dropped
Sprintffromdump's escape path. It now writes the hex digits straight into the buffer, which was the main cost for non-ASCII input.Numbers on Apple M1 Pro, JDK 21, i/s:
Output is byte-identical to master on a few thousand random strings across several encodings.