patricktoca / wyhash

The FASTEST QUALITY hash function, random number generators (PRNG) and hash map.

No hash function is perfect, but some are useful.

wyhash and wyrand are the ideal 64-bit hash function and PRNG respectively:

solid: wyhash passed SMHasher, wyrand passed BigCrush, practrand.

portable: 64-bit/32-bit system, big/little endian.

fastest: Efficient on 64-bit machines, especially for short keys.

simplest: In the sense of code size.

salted: We use dynamic secret to avoid intended attack.

wyhash is the default hasher for a hash table of the great Zig, V and Nim language.

Simple Example:

#include  "wyhash.h"
uint64_t _wyp[4];
make_secret(time(NULL),_wyp);
string  s="fcdskhfjs";
uint64_t h=wyhash(s.c_str(),s.size(),0,_wyp);

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g++-9 benchmark.cpp t1ha/src/t1ha2.c -o benchmark -Ofast -s -Wall -march=native

/usr/share/dict/words

hash function	short hash/us	bulk_256B GB/s	bulk_64KB GB/s
wyhash_final3	419.63	20.97	25.10
wyhash_final2	204.08	21.12	25.10
wyhash_final1	196.33	15.56	17.92
wyhash_gamma (dangerous)	399.92	19.16	25.80
wyhash_beta	180.51	18.20	17.37
wyhash_alpha	204.50	20.54	25.92
wyhash_v6 (avx2)	164.08	12.08	41.35
wyhash_v5	221.59	15.40	16.78
wyhash_v4	153.03	13.89	16.81
wyhash_v3	191.32	13.55	15.72
wyhash_v2	94.28	11.91	11.22
wyhash_v1	91.66	16.03	18.95
wyhash32 (32 bit)	149.78	5.45	4.89
xxh3_scalar	152.47	8.39	13.05
xxh3_avx2	144.62	9.85	44.82

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C# https://github.com/cocowalla/wyhash-dotnet

C++ https://github.com/tommyettinger/waterhash

GO https://github.com/dgryski/go-wyhash

GO https://github.com/orisano/wyhash

GO https://github.com/littleli/go-wyhash16

GO https://github.com/zeebo/wyhash

GO https://github.com/lonewolf3739/wyhash-go

GO https://github.com/zhangyunhao116/wyhash (final version 1)

Java https://github.com/OpenHFT/Zero-Allocation-Hashing

Nim https://github.com/nim-lang/Nim/blob/devel/lib/pure/hashes.nim

Nim https://github.com/jackhftang/wyhash.nim

Nim https://github.com/littleli/nim-wyhash16

Rust https://github.com/eldruin/wyhash-rs

Swift https://github.com/lemire/SwiftWyhash

Swift https://github.com/lemire/SwiftWyhashBenchmark

Swift https://github.com/jeudesprits/PSWyhash

V https://github.com/vlang/v/tree/master/vlib/hash/wyhash (v4)

Zig https://github.com/ManDeJan/zig-wyhash

absl hashmap https://github.com/abseil/abseil-cpp/blob/master/absl/hash/internal/wyhash.cc

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I thank these names:

Reini Urban

Dietrich Epp

Joshua Haberman

Tommy Ettinger

Daniel Lemire

Otmar Ertl

cocowalla

leo-yuriev

Diego Barrios Romero

paulie-g

dumblob

Yann Collet

ivte-ms

hyb

James Z.M. Gao

easyaspi314 (Devin)

TheOneric