/usr/share/gocode/src/github.com/chmduquesne/rollinghash/buzhash64/buzhash64_test.go is in golang-github-chmduquesne-rollinghash-dev 2.0.2+git20170321.9.043b8fd-4.
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 | package buzhash64_test
import (
"hash"
"math/rand"
"testing"
"time"
"github.com/chmduquesne/rollinghash"
rollsum "github.com/chmduquesne/rollinghash/buzhash64"
)
var testHash [256]uint64
func RandomHash() (res [256]uint64) {
used := make(map[uint64]bool)
for i, _ := range res {
x := uint64(rand.Int63())
for used[x] {
x = uint64(rand.Int63())
}
used[x] = true
res[i] = x
}
return res
}
func init() {
rand.Seed(time.Now().UTC().UnixNano())
testHash = RandomHash()
}
func NewRollingHash() rollinghash.Hash64 {
return rollsum.NewFromUint64Array(testHash)
}
// This is a no-op to prove that we implement hash.Hash64
var _ = hash.Hash64(rollsum.New())
func Sum32ByWriteAndRoll(b []byte) uint64 {
q := []byte(" ")
q = append(q, b...)
roll := NewRollingHash()
roll.Write(q[:len(q)-1])
roll.Roll(q[len(q)-1])
return roll.Sum64()
}
func Sum32ByWriteOnly(b []byte) uint64 {
roll := NewRollingHash()
roll.Write(b)
return roll.Sum64()
}
func RandomBytes() (res []byte) {
n := rand.Intn(8192)
res = make([]byte, n)
rand.Read(res)
return res
}
func TestBlackBox(t *testing.T) {
for i := 0; i < 1000; i++ {
in := RandomBytes()
if len(in) > 0 {
sum := Sum32ByWriteAndRoll(in)
ref := Sum32ByWriteOnly(in)
if ref != sum {
t.Errorf("Expected 0x%x, got 0x%x", ref, sum)
}
}
}
}
func BenchmarkRollingKB(b *testing.B) {
b.SetBytes(1024)
window := make([]byte, 1024)
for i := range window {
window[i] = byte(i)
}
h := rollsum.New()
in := make([]byte, 0, h.Size())
b.ResetTimer()
h.Write(window)
for i := 0; i < b.N; i++ {
h.Roll(byte(1024 + i))
h.Sum(in)
}
}
func BenchmarkRolling128B(b *testing.B) {
b.SetBytes(1024)
window := make([]byte, 128)
for i := range window {
window[i] = byte(i)
}
h := rollsum.New()
in := make([]byte, 0, h.Size())
b.ResetTimer()
h.Write(window)
for i := 0; i < b.N; i++ {
h.Roll(byte(128 + i))
h.Sum(in)
}
}
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