84 lines
1.6 KiB
Go
84 lines
1.6 KiB
Go
// +build !amd64 noasm
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package sip13
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import (
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"math/bits"
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"unsafe"
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)
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func Sum64(k0, k1 uint64, b []byte) uint64 {
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return Sum64Str(k0, k1, unsafeB2S(b))
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}
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func readUint64(b string) uint64 {
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_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
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return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
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uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
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}
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func unsafeB2S(b []byte) string {
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return *(*string)(unsafe.Pointer(&b))
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}
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func Sum64Str(k0, k1 uint64, p string) uint64 {
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var v0, v1, v2, v3 uint64
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v0 = k0 ^ 0x736f6d6570736575
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v1 = k1 ^ 0x646f72616e646f6d
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v2 = k0 ^ 0x6c7967656e657261
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v3 = k1 ^ 0x7465646279746573
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b := uint64(len(p)) << 56
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for len(p) >= 8 {
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m := readUint64(p)
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v3 ^= m
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v0 += v1
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v2 += v3
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v1 = bits.RotateLeft64(v1, 13)
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v3 = bits.RotateLeft64(v3, 16)
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v1 ^= v0
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v3 ^= v2
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v0 = bits.RotateLeft64(v0, 32)
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v2 += v1
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v0 += v3
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v1 = bits.RotateLeft64(v1, 17)
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v3 = bits.RotateLeft64(v3, 21)
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v1 ^= v2
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v3 ^= v0
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v2 = bits.RotateLeft64(v2, 32)
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v0 ^= m
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p = p[8:]
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}
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for _, c := range []byte(p) {
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b = bits.RotateLeft64(b|uint64(c), 56)
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}
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m := bits.RotateLeft64(b, len(p)*8)
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// last block with finalization
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v3 ^= m
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f := uint64(0xff)
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for i := 0; i < 4; i++ {
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v0 += v1
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v2 += v3
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v1 = bits.RotateLeft64(v1, 13)
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v3 = bits.RotateLeft64(v3, 16)
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v1 ^= v0
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v3 ^= v2
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v0 = bits.RotateLeft64(v0, 32)
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v2 += v1
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v0 += v3
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v1 = bits.RotateLeft64(v1, 17)
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v3 = bits.RotateLeft64(v3, 21)
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v1 ^= v2
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v3 ^= v0
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v2 = bits.RotateLeft64(v2, 32)
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v2 ^= f
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v0 ^= m
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m, f = 0, 0 // clear last block and finalization mixins
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}
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return v0 ^ v1 ^ v2 ^ v3
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}
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