gh-121562: optimized hex_from_char #121563
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mdickinson
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Jul 10, 2024
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LGTM in principle. The old code is agnostic to character encoding (works equally well with ASCII / EBCDIC / whatever), while the new code is based on the bytes of the UTF8-encoded string. That's fine, since the only use-case is applying this to a UTF-8-encoded value. But please could we add a comment that makes it clear that this table should only be used with encodings whose lower half is ASCII (like UTF-8).
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Hello @mdickinson, thanks for your time, I just added the comment clarifying it but my English is average, anything let me know! |
mdickinson
approved these changes
Jul 14, 2024
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@LimaBD Merged. Thank you for the contribution! |
estyxx
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Jul 17, 2024
Performance improvement to `float.fromhex`: use a lookup table for computing the hexadecimal value of a character, in place of the previous switch-case construct. Patch by Bruno Lima.
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Optimized hex_from_char performance
issue #121562
Timing with old hex_from_char:
With new hex_from_char:
If we measure
hex_from_chardirectly, probably we will get a much better % improvement because there is additional calls thatfloat.fromhexmakes apart from this one.