Current File : //usr/local/go/src/runtime/hash32.go
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Hashing algorithm inspired by
// wyhash: https://github.com/wangyi-fudan/wyhash/blob/ceb019b530e2c1c14d70b79bfa2bc49de7d95bc1/Modern%20Non-Cryptographic%20Hash%20Function%20and%20Pseudorandom%20Number%20Generator.pdf
//go:build 386 || arm || mips || mipsle
// +build 386 arm mips mipsle
package runtime
import "unsafe"
func memhash32Fallback(p unsafe.Pointer, seed uintptr) uintptr {
a, b := mix32(uint32(seed), uint32(4^hashkey[0]))
t := readUnaligned32(p)
a ^= t
b ^= t
a, b = mix32(a, b)
a, b = mix32(a, b)
return uintptr(a ^ b)
}
func memhash64Fallback(p unsafe.Pointer, seed uintptr) uintptr {
a, b := mix32(uint32(seed), uint32(8^hashkey[0]))
a ^= readUnaligned32(p)
b ^= readUnaligned32(add(p, 4))
a, b = mix32(a, b)
a, b = mix32(a, b)
return uintptr(a ^ b)
}
func memhashFallback(p unsafe.Pointer, seed, s uintptr) uintptr {
a, b := mix32(uint32(seed), uint32(s^hashkey[0]))
if s == 0 {
return uintptr(a ^ b)
}
for ; s > 8; s -= 8 {
a ^= readUnaligned32(p)
b ^= readUnaligned32(add(p, 4))
a, b = mix32(a, b)
p = add(p, 8)
}
if s >= 4 {
a ^= readUnaligned32(p)
b ^= readUnaligned32(add(p, s-4))
} else {
t := uint32(*(*byte)(p))
t |= uint32(*(*byte)(add(p, s>>1))) << 8
t |= uint32(*(*byte)(add(p, s-1))) << 16
b ^= t
}
a, b = mix32(a, b)
a, b = mix32(a, b)
return uintptr(a ^ b)
}
func mix32(a, b uint32) (uint32, uint32) {
c := uint64(a^uint32(hashkey[1])) * uint64(b^uint32(hashkey[2]))
return uint32(c), uint32(c >> 32)
}
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