/usr/share/gocode/src/github.com/retailnext/hllpp/murmur.go is in golang-github-retailnext-hllpp-dev 1.0.0+git20170901.6e8b6d3-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 | // Copyright (c) 2015, RetailNext, Inc.
// All rights reserved.
package hllpp
import (
"encoding/binary"
"reflect"
"unsafe"
)
// Non-streaming implementation of murmur3. Not only is it faster to begin with
// vs cryptographic hashing functions, but I can avoid memory allocations by
// not using the go streaming hash.Hash interface.
const (
murmurC1 = 0x87c37b91114253d5
murmurC2 = 0x4cf5ad432745937f
)
var bigEndian bool
func init() {
var t uint16 = 1
bigEndian = (*[2]byte)(unsafe.Pointer(&t))[0] == 0
}
// This is a port of MurmurHash3_x64_128 from MurmurHash3.cpp
func murmurSum64(data []byte) uint64 {
var h1, h2, k1, k2 uint64
len := len(data)
nBlocks := len / 16
var data64 []uint64
if bigEndian {
data64 = make([]uint64, nBlocks*2)
for i := 0; i < nBlocks*2; i++ {
data64[i] = binary.LittleEndian.Uint64(data[8*i:])
}
} else {
dataHeader := (*reflect.SliceHeader)(unsafe.Pointer(&data))
data64Header := (*reflect.SliceHeader)(unsafe.Pointer(&data64))
data64Header.Data = dataHeader.Data
data64Header.Len = 2 * nBlocks
data64Header.Cap = 2 * nBlocks
}
for i := 0; i < nBlocks; i++ {
k1 = data64[2*i]
k2 = data64[2*i+1]
k1 *= murmurC1
k1 = (k1 << 31) | (k1 >> (64 - 31))
k1 *= murmurC2
h1 ^= k1
h1 = (h1 << 27) | (h1 >> (64 - 27))
h1 += h2
h1 = h1*5 + 0x52dce729
k2 *= murmurC2
k2 = (k2 << 33) | (k2 >> (64 - 33))
k2 *= murmurC1
h2 ^= k2
h2 = (h2 << 31) | (h2 >> (64 - 31))
h2 += h1
h2 = h2*5 + 0x38495ab5
}
tail := data[nBlocks*16:]
k1, k2 = 0, 0
switch len & 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]) << 0
k2 *= murmurC2
k2 = (k2 << 33) | (k2 >> (64 - 33))
k2 *= murmurC1
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]) << 0
k1 *= murmurC1
k1 = (k1 << 31) | (k1 >> (64 - 31))
k1 *= murmurC2
h1 ^= k1
}
h1 ^= uint64(len)
h2 ^= uint64(len)
h1 += h2
h2 += h1
h1 ^= h1 >> 33
h1 *= 0xff51afd7ed558ccd
h1 ^= h1 >> 33
h1 *= 0xc4ceb9fe1a85ec53
h1 ^= h1 >> 33
h2 ^= h2 >> 33
h2 *= 0xff51afd7ed558ccd
h2 ^= h2 >> 33
h2 *= 0xc4ceb9fe1a85ec53
h2 ^= h2 >> 33
h1 += h2
h2 += h1
return h1
}
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