70 lines
1.9 KiB
Go
70 lines
1.9 KiB
Go
// Copyright 2014 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Hashing algorithm inspired by
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// wyhash: https://github.com/wangyi-fudan/wyhash/blob/ceb019b530e2c1c14d70b79bfa2bc49de7d95bc1/Modern%20Non-Cryptographic%20Hash%20Function%20and%20Pseudorandom%20Number%20Generator.pdf
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//go:build 386 || arm || mips || mipsle || armbe || m68k || nios2 || ppc || riscv || s390 || sh || shbe || sparc
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// +build 386 arm mips mipsle armbe m68k nios2 ppc riscv s390 sh shbe sparc
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package runtime
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import "unsafe"
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// For gccgo, use go:linkname to export compiler-called functions.
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//
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//go:linkname memhash
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func memhash32(p unsafe.Pointer, seed uintptr) uintptr {
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a, b := mix32(uint32(seed), uint32(4^hashkey[0]))
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t := readUnaligned32(p)
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a ^= t
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b ^= t
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a, b = mix32(a, b)
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a, b = mix32(a, b)
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return uintptr(a ^ b)
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}
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func memhash64(p unsafe.Pointer, seed uintptr) uintptr {
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a, b := mix32(uint32(seed), uint32(8^hashkey[0]))
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a ^= readUnaligned32(p)
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b ^= readUnaligned32(add(p, 4))
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a, b = mix32(a, b)
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a, b = mix32(a, b)
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return uintptr(a ^ b)
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}
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func memhash(p unsafe.Pointer, seed, s uintptr) uintptr {
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if GOARCH == "386" && GOOS != "nacl" && useAeshash {
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return aeshash(p, seed, s)
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}
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a, b := mix32(uint32(seed), uint32(s^hashkey[0]))
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if s == 0 {
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return uintptr(a ^ b)
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}
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for ; s > 8; s -= 8 {
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a ^= readUnaligned32(p)
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b ^= readUnaligned32(add(p, 4))
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a, b = mix32(a, b)
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p = add(p, 8)
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}
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if s >= 4 {
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a ^= readUnaligned32(p)
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b ^= readUnaligned32(add(p, s-4))
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} else {
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t := uint32(*(*byte)(p))
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t |= uint32(*(*byte)(add(p, s>>1))) << 8
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t |= uint32(*(*byte)(add(p, s-1))) << 16
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b ^= t
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}
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a, b = mix32(a, b)
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a, b = mix32(a, b)
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return uintptr(a ^ b)
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}
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func mix32(a, b uint32) (uint32, uint32) {
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c := uint64(a^uint32(hashkey[1])) * uint64(b^uint32(hashkey[2]))
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return uint32(c), uint32(c >> 32)
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}
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