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| author | c-blake <c-blake@users.noreply.github.com> | 2024-06-19 04:49:57 +0000 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2024-06-19 06:49:57 +0200 |
| commit | e64512036289434c6a7b377f52a50189beae75e8 (patch) | |
| tree | 89f6d7bec38553927602a42e6146065894c1139f /changelog.md | |
| parent | 9d08d26e3307cf5d21271fd30d983f8d1c66ec50 (diff) | |
| download | Nim-e64512036289434c6a7b377f52a50189beae75e8.tar.gz | |
Add Farm Hash conditioned upon `nimPreviewHashFarm` as 64-bit `Hash` (#23735)
Unlike present Nim this actually fills `Hash` 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.Diffstat (limited to 'changelog.md')
| -rw-r--r-- | changelog.md | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/changelog.md b/changelog.md index 53d88b19f..92abb2614 100644 --- a/changelog.md +++ b/changelog.md @@ -39,6 +39,9 @@ slots when enlarging a sequence. objects the cyclic collector did free. If the number is zero that is a strong indicator that you can use `--mm:arc` instead of `--mm:orc`. - A `$` template is provided for `Path` in `std/paths`. +- `nimPreviewHashFarm` has been added to `lib/pure/hashes.nim` to default to a +64-bit string `Hash` (based upon Google's Farm Hash) which is also faster than +the present one. At present, this is incompatible with `--jsbigint=off` mode. [//]: # "Deprecations:" |