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|
// +build appengine
package murmur
import "encoding/binary"
func Murmur3H1(data []byte) uint64 {
length := len(data)
var h1, h2, k1, k2 uint64
const (
c1 = 0x87c37b91114253d5
c2 = 0x4cf5ad432745937f
)
// body
nBlocks := length / 16
for i := 0; i < nBlocks; i++ {
// block := (*[2]uint64)(unsafe.Pointer(&data[i*16]))
k1 = binary.LittleEndian.Uint64(data[i*16:])
k2 = binary.LittleEndian.Uint64(data[(i*16)+8:])
k1 *= c1
k1 = (k1 << 31) | (k1 >> 33) // ROTL64(k1, 31)
k1 *= c2
h1 ^= k1
h1 = (h1 << 27) | (h1 >> 37) // ROTL64(h1, 27)
h1 += h2
h1 = h1*5 + 0x52dce729
k2 *= c2
k2 = (k2 << 33) | (k2 >> 31) // ROTL64(k2, 33)
k2 *= c1
h2 ^= k2
h2 = (h2 << 31) | (h2 >> 33) // ROTL64(h2, 31)
h2 += h1
h2 = h2*5 + 0x38495ab5
}
// tail
tail := data[nBlocks*16:]
k1 = 0
k2 = 0
switch length & 15 {
case 15:
k2 ^= uint64(tail[14]) << 48
fallthrough
case 14:
k2 ^= uint64(tail[13]) << 40
fallthrough
case 13:
k2 ^= uint64(tail[12]) << 32
fallthrough
case 12:
k2 ^= uint64(tail[11]) << 24
fallthrough
case 11:
k2 ^= uint64(tail[10]) << 16
fallthrough
case 10:
k2 ^= uint64(tail[9]) << 8
fallthrough
case 9:
k2 ^= uint64(tail[8])
k2 *= c2
k2 = (k2 << 33) | (k2 >> 31) // ROTL64(k2, 33)
k2 *= c1
h2 ^= k2
fallthrough
case 8:
k1 ^= uint64(tail[7]) << 56
fallthrough
case 7:
k1 ^= uint64(tail[6]) << 48
fallthrough
case 6:
k1 ^= uint64(tail[5]) << 40
fallthrough
case 5:
k1 ^= uint64(tail[4]) << 32
fallthrough
case 4:
k1 ^= uint64(tail[3]) << 24
fallthrough
case 3:
k1 ^= uint64(tail[2]) << 16
fallthrough
case 2:
k1 ^= uint64(tail[1]) << 8
fallthrough
case 1:
k1 ^= uint64(tail[0])
k1 *= c1
k1 = (k1 << 31) | (k1 >> 33) // ROTL64(k1, 31)
k1 *= c2
h1 ^= k1
}
h1 ^= uint64(length)
h2 ^= uint64(length)
h1 += h2
h2 += h1
// finalizer
const (
fmix1 = 0xff51afd7ed558ccd
fmix2 = 0xc4ceb9fe1a85ec53
)
// fmix64(h1)
h1 ^= h1 >> 33
h1 *= fmix1
h1 ^= h1 >> 33
h1 *= fmix2
h1 ^= h1 >> 33
// fmix64(h2)
h2 ^= h2 >> 33
h2 *= fmix1
h2 ^= h2 >> 33
h2 *= fmix2
h2 ^= h2 >> 33
h1 += h2
// the following is extraneous since h2 is discarded
// h2 += h1
return h1
}
|
