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hash/maphash: sync wyhash with runtime implementation

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Fixes #69940

Change-Id: I40535d2647f9456d2196241bf7414b1e92b53c2c
Reviewed-on: https://go-review.googlesource.com/c/go/+/621756
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>
This commit is contained in:
Cuong Manh Le 2024-10-22 14:56:17 +07:00
parent cb69354de3
commit 0f2353997a
1 changed files with 15 additions and 13 deletions
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28
src/hash/maphash/maphash_purego.go
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@ -13,6 +13,14 @@ import (
"reflect" "reflect"
) )
var hashkey [4]uint64
func init() {
for i := range hashkey {
hashkey[i] = randUint64()
}
}
func rthash(buf []byte, seed uint64) uint64 { func rthash(buf []byte, seed uint64) uint64 {
if len(buf) == 0 { if len(buf) == 0 {
return seed return seed
@ -33,34 +41,28 @@ func randUint64() uint64 {
// This is a port of wyhash implementation in runtime/hash64.go, // This is a port of wyhash implementation in runtime/hash64.go,
// without using unsafe for purego. // without using unsafe for purego.
const ( const m5 = 0x1d8e4e27c47d124f
m1 = 0xa0761d6478bd642f
m2 = 0xe7037ed1a0b428db
m3 = 0x8ebc6af09c88c6e3
m4 = 0x589965cc75374cc3
m5 = 0x1d8e4e27c47d124f
)
func wyhash(key []byte, seed, len uint64) uint64 { func wyhash(key []byte, seed, len uint64) uint64 {
p := key p := key
i := len i := len
var a, b uint64 var a, b uint64
seed ^= m1 seed ^= hashkey[0]
if i > 16 { if i > 16 {
if i > 48 { if i > 48 {
seed1 := seed seed1 := seed
seed2 := seed seed2 := seed
for ; i > 48; i -= 48 { for ; i > 48; i -= 48 {
seed = mix(r8(p)^m2, r8(p[8:])^seed) seed = mix(r8(p)^hashkey[1], r8(p[8:])^seed)
seed1 = mix(r8(p[16:])^m3, r8(p[24:])^seed1) seed1 = mix(r8(p[16:])^hashkey[2], r8(p[24:])^seed1)
seed2 = mix(r8(p[32:])^m4, r8(p[40:])^seed2) seed2 = mix(r8(p[32:])^hashkey[3], r8(p[40:])^seed2)
p = p[48:] p = p[48:]
} }
seed ^= seed1 ^ seed2 seed ^= seed1 ^ seed2
} }
for ; i > 16; i -= 16 { for ; i > 16; i -= 16 {
seed = mix(r8(p)^m2, r8(p[8:])^seed) seed = mix(r8(p)^hashkey[1], r8(p[8:])^seed)
p = p[16:] p = p[16:]
} }
} }
@ -74,7 +76,7 @@ func wyhash(key []byte, seed, len uint64) uint64 {
a = r4(p)<<32 | r4(p[n:]) a = r4(p)<<32 | r4(p[n:])
b = r4(p[i-4:])<<32 | r4(p[i-4-n:]) b = r4(p[i-4:])<<32 | r4(p[i-4-n:])
} }
return mix(m5^len, mix(a^m2, b^seed)) return mix(m5^len, mix(a^hashkey[1], b^seed))
} }
func r3(p []byte, k uint64) uint64 { func r3(p []byte, k uint64) uint64 {