Add Farm Hash conditioned upon nimPreviewHashFarm as 64-bit Hash
#23735
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actually filling hash function for `string` & related.
For the curious, note that `hashData` remains the aboriginal Nim string
hasher & `import hashes {.all.}` allows simultaneous test/time of {orig,
murmur, farm} on your favorite CPU & back end compiler.
Update tests also conditioned upon `nimPreviewHashFarm` so they should
pass either with or without that `define` on.
In `--jsbigint=on` mode, only the lower 32-bits of `Hash` match nimvm &
run-time values because `type Hash = int` and on JS int=int32, not int64
as for 64-bit Nim platforms. Due to the matching, `const` Table should
match run-time `Table` on all platforms.
To operate in `--jsbigint=off` mode is feasible but needs much "double
precision mul/xor/ror/shr-arithmetic"-style work. That is distracting &
also of questionable value since JS added BigInt in 2018, ringabout
added Nim support for it in 2021 & `nimPreviewHashFarm` is unlikely to
swap from an opt-in to an opt-out default before 2025..2026 which will
have given a backward looking time window of 7..8 years for deployment
platforms - reasonably generous.
Add a changelog entry for 2.2.
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Cross ref to #23678 discussion. |
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FWIW, the failing tests have nothing to do with this PR (although perhaps the non-deterministic 7 second timeout in |
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Should |
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Personally, I think |
and simplify/clarify the language a little while doing so.
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We could even make it the default for 2.2 as long as it works with JavaScript out of the box too. (We need to make --jsbigint=on the default.) |
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Thanks for your hard work on this PR! Hint: mm: orc; opt: speed; options: -d:release |
The tests need to be enabled with |
Unlike present Nim this actually fills
Hashforstring& related.For the curious, note that
hashDataremains the aboriginal Nim string hasher &import hashes {.all.}allows simultaneous test/time of {orig, murmur, farm} on your favorite CPU & back end compiler.Update tests also conditioned upon
nimPreviewHashFarmso they should pass either with or without thatdefineon.In
--jsbigint=onmode, only the lower 32-bits ofHashmatch nimvm & run-time values becausetype Hash = intand on JS int=int32, not int64 as for 64-bit Nim platforms. Due to the matching,constTable should match run-timeTableon all platforms.To operate in
--jsbigint=offmode is feasible but needs much "double precision mul/xor/ror/shr-arithmetic"-style work. That is distracting & also of questionable value since JS added BigInt in 2018, ringabout added Nim support for it in 2021 &nimPreviewHashFarmis unlikely to swap from an opt-in to an opt-out default before 2025..2026 which will have given a backward looking time window of 7..8 years for deployment platforms - reasonably generous.Add a changelog entry for 2.2.