onedrive: implement quickXorHash algorithm #2262

This commit is contained in:
Nick Craig-Wood 2018-04-20 09:54:27 +01:00
parent 34ba17deec
commit 57a5b72d60
2 changed files with 371 additions and 0 deletions

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// Package quickxorhash provides the quickXorHash algorithm which is a
// quick, simple non-cryptographic hash algorithm that works by XORing
// the bytes in a circular-shifting fashion.
//
// It is used by Microsoft Onedrive for Business to hash data.
//
// See: https://docs.microsoft.com/en-us/onedrive/developer/code-snippets/quickxorhash
package quickxorhash
// This code was ported from the code snippet linked from
// https://docs.microsoft.com/en-us/onedrive/developer/code-snippets/quickxorhash
// Which has the copyright
// ------------------------------------------------------------------------------
// Copyright (c) 2016 Microsoft Corporation
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
// ------------------------------------------------------------------------------
import (
"hash"
)
const (
// BlockSize is the preferred size for hashing
BlockSize = 64
// Size of the output checksum
Size = 20
bitsInLastCell = 32
shift = 11
threshold = 600
widthInBits = 8 * Size
dataSize = (widthInBits-1)/64 + 1
)
type quickXorHash struct {
data [dataSize]uint64
lengthSoFar uint64
shiftSoFar int
}
// New returns a new hash.Hash computing the quickXorHash checksum.
func New() hash.Hash {
return &quickXorHash{}
}
// Write (via the embedded io.Writer interface) adds more data to the running hash.
// It never returns an error.
//
// Write writes len(p) bytes from p to the underlying data stream. It returns
// the number of bytes written from p (0 <= n <= len(p)) and any error
// encountered that caused the write to stop early. Write must return a non-nil
// error if it returns n < len(p). Write must not modify the slice data, even
// temporarily.
//
// Implementations must not retain p.
func (q *quickXorHash) Write(p []byte) (n int, err error) {
currentshift := q.shiftSoFar
// The bitvector where we'll start xoring
vectorArrayIndex := currentshift / 64
// The position within the bit vector at which we begin xoring
vectorOffset := currentshift % 64
iterations := len(p)
if iterations > widthInBits {
iterations = widthInBits
}
for i := 0; i < iterations; i++ {
isLastCell := vectorArrayIndex == len(q.data)-1
var bitsInVectorCell int
if isLastCell {
bitsInVectorCell = bitsInLastCell
} else {
bitsInVectorCell = 64
}
// There's at least 2 bitvectors before we reach the end of the array
if vectorOffset <= bitsInVectorCell-8 {
for j := i; j < len(p); j += widthInBits {
q.data[vectorArrayIndex] ^= uint64(p[j]) << uint(vectorOffset)
}
} else {
index1 := vectorArrayIndex
var index2 int
if isLastCell {
index2 = 0
} else {
index2 = vectorArrayIndex + 1
}
low := byte(bitsInVectorCell - vectorOffset)
xoredByte := byte(0)
for j := i; j < len(p); j += widthInBits {
xoredByte ^= p[j]
}
q.data[index1] ^= uint64(xoredByte) << uint(vectorOffset)
q.data[index2] ^= uint64(xoredByte) >> low
}
vectorOffset += shift
for vectorOffset >= bitsInVectorCell {
if isLastCell {
vectorArrayIndex = 0
} else {
vectorArrayIndex = vectorArrayIndex + 1
}
vectorOffset -= bitsInVectorCell
}
}
// Update the starting position in a circular shift pattern
q.shiftSoFar = (q.shiftSoFar + shift*(len(p)%widthInBits)) % widthInBits
q.lengthSoFar += uint64(len(p))
return len(p), nil
}
// Calculate the current checksum
func (q *quickXorHash) checkSum() (h [Size]byte) {
// Output the data as little endian bytes
ph := 0
for _, d := range q.data[:len(q.data)-1] {
_ = h[ph+7] // bounds check
h[ph+0] = byte(d >> (8 * 0))
h[ph+1] = byte(d >> (8 * 1))
h[ph+2] = byte(d >> (8 * 2))
h[ph+3] = byte(d >> (8 * 3))
h[ph+4] = byte(d >> (8 * 4))
h[ph+5] = byte(d >> (8 * 5))
h[ph+6] = byte(d >> (8 * 6))
h[ph+7] = byte(d >> (8 * 7))
ph += 8
}
// remaining 32 bits
d := q.data[len(q.data)-1]
h[Size-4] = byte(d >> (8 * 0))
h[Size-3] = byte(d >> (8 * 1))
h[Size-2] = byte(d >> (8 * 2))
h[Size-1] = byte(d >> (8 * 3))
// XOR the file length with the least significant bits in little endian format
d = q.lengthSoFar
h[Size-8] ^= byte(d >> (8 * 0))
h[Size-7] ^= byte(d >> (8 * 1))
h[Size-6] ^= byte(d >> (8 * 2))
h[Size-5] ^= byte(d >> (8 * 3))
h[Size-4] ^= byte(d >> (8 * 4))
h[Size-3] ^= byte(d >> (8 * 5))
h[Size-2] ^= byte(d >> (8 * 6))
h[Size-1] ^= byte(d >> (8 * 7))
return h
}
// Sum appends the current hash to b and returns the resulting slice.
// It does not change the underlying hash state.
func (q *quickXorHash) Sum(b []byte) []byte {
hash := q.checkSum()
return append(b, hash[:]...)
}
// Reset resets the Hash to its initial state.
func (q *quickXorHash) Reset() {
*q = quickXorHash{}
}
// Size returns the number of bytes Sum will return.
func (q *quickXorHash) Size() int {
return Size
}
// BlockSize returns the hash's underlying block size.
// The Write method must be able to accept any amount
// of data, but it may operate more efficiently if all writes
// are a multiple of the block size.
func (q *quickXorHash) BlockSize() int {
return BlockSize
}
// Sum returns the quickXorHash checksum of the data.
func Sum(data []byte) [Size]byte {
var d quickXorHash
_, _ = d.Write(data)
return d.checkSum()
}

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package quickxorhash
import (
"encoding/base64"
"fmt"
"hash"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
)
var testVectors = []struct {
size int
in string
out string
}{
{0, ``, "AAAAAAAAAAAAAAAAAAAAAAAAAAA="},
{1, `Sg==`, "SgAAAAAAAAAAAAAAAQAAAAAAAAA="},
{2, `tbQ=`, "taAFAAAAAAAAAAAAAgAAAAAAAAA="},
{3, `0pZP`, "0rDEEwAAAAAAAAAAAwAAAAAAAAA="},
{4, `jRRDVA==`, "jaDAEKgAAAAAAAAABAAAAAAAAAA="},
{5, `eAV52qE=`, "eChAHrQRCgAAAAAABQAAAAAAAAA="},
{6, `luBZlaT6`, "lgBHFipBCn0AAAAABgAAAAAAAAA="},
{7, `qaApEj66lw==`, "qQBFCiTgA11cAgAABwAAAAAAAAA="},
{8, `/aNzzCFPS/A=`, "/RjFHJgRgicsAR4ACAAAAAAAAAA="},
{9, `n6Neh7p6fFgm`, "nxiFFw6hCz3wAQsmCQAAAAAAAAA="},
{10, `J9iPGCbfZSTNyw==`, "J8DGIzBggm+UgQTNUgYAAAAAAAA="},
{11, `i+UZyUGJKh+ISbk=`, "iyhHBpIRhESo4AOIQ0IuAAAAAAA="},
{12, `h490d57Pqz5q2rtT`, "h3gEHe7giWeswgdq3MYupgAAAAA="},
{13, `vPgoDjOfO6fm71RxLw==`, "vMAHChwwg0/s4BTmdQcV4vACAAA="},
{14, `XoJ1AsoR4fDYJrDqYs4=`, "XhBEHQSgjAiEAx7YPgEs1CEGZwA="},
{15, `gQaybEqS/4UlDc8e4IJm`, "gDCALNigBEn8oxAlZ8AzPAAOQZg="},
{16, `2fuxhBJXtpWFe8dOfdGeHw==`, "O9tHLAghgSvYohKFyMMxnNCHaHg="},
{17, `XBV6YKU9V7yMakZnFIxIkuU=`, "HbplHsBQih5cgReMQYMRzkABRiA="},
{18, `XJZSOiNO2bmfKnTKD7fztcQX`, "/6ZArHQwAidkIxefQgEdlPGAW8w="},
{19, `g8VtAh+2Kf4k0kY5tzji2i2zmA==`, "wDNrgwHWAVukwB8kg4YRcnALHIg="},
{20, `T6LYJIfDh81JrAK309H2JMJTXis=`, "zBTHrspn3mEcohlJdIUAbjGNaNg="},
{21, `DWAAX5/CIfrmErgZa8ot6ZraeSbu`, "LR2Z0PjuRYGKQB/mhQAuMrAGZbQ="},
{22, `N9abi3qy/mC1THZuVLHPpx7SgwtLOA==`, "1KTYttCBEen8Hwy1doId3ECFWDw="},
{23, `LlUe7wHerLqEtbSZLZgZa9u0m7hbiFs=`, "TqVZpxs3cN61BnuFvwUtMtECTGQ="},
{24, `bU2j/0XYdgfPFD4691jV0AOUEUPR4Z5E`, "bnLBiLpVgnxVkXhNsIAPdHAPLFQ="},
{25, `lScPwPsyUsH2T1Qsr31wXtP55Wqbe47Uyg==`, "VDMSy8eI26nBHCB0e8gVWPCKPsA="},
{26, `rJaKh1dLR1k+4hynliTZMGf8Nd4qKKoZiAM=`, "r7bjwkl8OYQeNaMcCY8fTmEJEmQ="},
{27, `pPsT0CPmHrd3Frsnva1pB/z1ytARLeHEYRCo`, "Rdg7rCcDomL59pL0s6GuTvqLVqQ="},
{28, `wSRChaqmrsnMrfB2yqI43eRWbro+f9kBvh+01w==`, "YTtloIi6frI7HX3vdLvE7I2iUOA="},
{29, `apL67KMIRxQeE9k1/RuW09ppPjbF1WeQpTjSWtI=`, "CIpedls+ZlSQ654fl+X26+Q7LVU="},
{30, `53yx0/QgMTVb7OOzHRHbkS7ghyRc+sIXxi7XHKgT`, "zfJtLGFgR9DB3Q64fAFIp+S5iOY="},
{31, `PwXNnutoLLmxD8TTog52k8cQkukmT87TTnDipKLHQw==`, "PTaGs7yV3FUyBy/SfU6xJRlCJlI="},
{32, `NbYXsp5/K6mR+NmHwExjvWeWDJFnXTKWVlzYHoesp2E=`, "wjuAuWDiq04qDt1R8hHWDDcwVoQ="},
{33, `qQ70RB++JAR5ljNv3lJt1PpqETPsckopfonItu18Cr3E`, "FkJaeg/0Z5+euShYlLpE2tJh+Lo="},
{34, `RhzSatQTQ9/RFvpHyQa1WLdkr3nIk6MjJUma998YRtp44A==`, "SPN2D29reImAqJezlqV2DLbi8tk="},
{35, `DND1u1uZ5SqZVpRUk6NxSUdVo7IjjL9zs4A1evDNCDLcXWc=`, "S6lBk2hxI2SWBfn7nbEl7D19UUs="},
{36, `jEi62utFz69JMYHjg1iXy7oO6ZpZSLcVd2B+pjm6BGsv/CWi`, "s0lYU9tr/bp9xsnrrjYgRS5EvV8="},
{37, `hfS3DZZnhy0hv7nJdXLv/oJOtIgAuP9SInt/v8KeuO4/IvVh4A==`, "CV+HQCdd2A/e/vdi12f2UU55GLA="},
{38, `EkPQAC6ymuRrYjIXD/LT/4Vb+7aTjYVZOHzC8GPCEtYDP0+T3Nc=`, "kE9H9sEmr3vHBYUiPbvsrcDgSEo="},
{39, `vtBOGIENG7yQ/N7xNWPNIgy66Gk/I2Ur/ZhdFNUK9/1FCZuu/KeS`, "+Fgp3HBimtCzUAyiinj3pkarYTk="},
{40, `YnF4smoy9hox2jBlJ3VUa4qyCRhOZbWcmFGIiszTT4zAdYHsqJazyg==`, "arkIn+ELddmE8N34J9ydyFKW+9w="},
{41, `0n7nl3YJtipy6yeUbVPWtc2h45WbF9u8hTz5tNwj3dZZwfXWkk+GN3g=`, "YJLNK7JR64j9aODWfqDvEe/u6NU="},
{42, `FnIIPHayc1pHkY4Lh8+zhWwG8xk6Knk/D3cZU1/fOUmRAoJ6CeztvMOL`, "22RPOylMtdk7xO/QEQiMli4ql0k="},
{43, `J82VT7ND0Eg1MorSfJMUhn+qocF7PsUpdQAMrDiHJ2JcPZAHZ2nyuwjoKg==`, "pOR5eYfwCLRJbJsidpc1rIJYwtM="},
{44, `Zbu+78+e35ZIymV5KTDdub5McyI3FEO8fDxs62uWHQ9U3Oh3ZqgaZ30SnmQ=`, "DbvbTkgNTgWRqRidA9r1jhtUjro="},
{45, `lgybK3Da7LEeY5aeeNrqcdHvv6mD1W4cuQ3/rUj2C/CNcSI0cAMw6vtpVY3y`, "700RQByn1lRQSSme9npQB/Ye+bY="},
{46, `jStZgKHv4QyJLvF2bYbIUZi/FscHALfKHAssTXkrV1byVR9eACwW9DNZQRHQwg==`, "uwN55He8xgE4g93dH9163xPew4U="},
{47, `V1PSud3giF5WW72JB/bgtltsWtEB5V+a+wUALOJOGuqztzVXUZYrvoP3XV++gM0=`, "U+3ZfUF/6mwOoHJcSHkQkckfTDA="},
{48, `VXs4t4tfXGiWAL6dlhEMm0YQF0f2w9rzX0CvIVeuW56o6/ec2auMpKeU2VeteEK5`, "sq24lSf7wXLH8eigHl07X+qPTps="},
{49, `bLUn3jLH+HFUsG3ptWTHgNvtr3eEv9lfKBf0jm6uhpqhRwtbEQ7Ovj/hYQf42zfdtQ==`, "uC8xrnopGiHebGuwgq607WRQyxQ="},
{50, `4SVmjtXIL8BB8SfkbR5Cpaljm2jpyUfAhIBf65XmKxHlz9dy5XixgiE/q1lv+esZW/E=`, "wxZ0rxkMQEnRNAp8ZgEZLT4RdLM="},
{51, `pMljctlXeFUqbG3BppyiNbojQO3ygg6nZPeUZaQcVyJ+Clgiw3Q8ntLe8+02ZSfyCc39`, "aZEPmNvOXnTt7z7wt+ewV7QGMlg="},
{52, `C16uQlxsHxMWnV2gJhFPuJ2/guZ4N1YgmNvAwL1yrouGQtwieGx8WvZsmYRnX72JnbVtTw==`, "QtlSNqXhVij64MMhKJ3EsDFB/z8="},
{53, `7ZVDOywvrl3L0GyKjjcNg2CcTI81n2CeUbzdYWcZOSCEnA/xrNHpiK01HOcGh3BbxuS4S6g=`, "4NznNJc4nmXeApfiCFTq/H5LbHw="},
{54, `JXm2tTVqpYuuz2Cc+ZnPusUb8vccPGrzWK2oVwLLl/FjpFoxO9FxGlhnB08iu8Q/XQSdzHn+`, "IwE5+2pKNcK366I2k2BzZYPibSI="},
{55, `TiiU1mxzYBSGZuE+TX0l9USWBilQ7dEml5lLrzNPh75xmhjIK8SGqVAkvIMgAmcMB+raXdMPZg==`, "yECGHtgR128ScP4XlvF96eLbIBE="},
{56, `zz+Q4zi6wh0fCJUFU9yUOqEVxlIA93gybXHOtXIPwQQ44pW4fyh6BRgc1bOneRuSWp85hwlTJl8=`, "+3Ef4D6yuoC8J+rbFqU1cegverE="},
{57, `sa6SHK9z/G505bysK5KgRO2z2cTksDkLoFc7sv0tWBmf2G2mCiozf2Ce6EIO+W1fRsrrtn/eeOAV`, "xZg1CwMNAjN0AIXw2yh4+1N3oos="},
{58, `0qx0xdyTHhnKJ22IeTlAjRpWw6y2sOOWFP75XJ7cleGJQiV2kyrmQOST4DGHIL0qqA7sMOdzKyTV
iw==`, "bS0tRYPkP1Gfc+ZsBm9PMzPunG8="},
{59, `QuzaF0+5ooig6OLEWeibZUENl8EaiXAQvK9UjBEauMeuFFDCtNcGs25BDtJGGbX90gH4VZvCCDNC
q4s=`, "rggokuJq1OGNOfB6aDp2g4rdPgw="},
{60, `+wg2x23GZQmMLkdv9MeAdettIWDmyK6Wr+ba23XD+Pvvq1lIMn9QIQT4Z7QHJE3iC/ZMFgaId9VA
yY3d`, "ahQbTmOdiKUNdhYRHgv5/Ky+Y6k="},
{61, `y0ydRgreRQwP95vpNP92ioI+7wFiyldHRbr1SfoPNdbKGFA0lBREaBEGNhf9yixmfE+Azo2AuROx
b7Yc7g==`, "cJKFc0dXfiN4hMg1lcMf5E4gqvo="},
{62, `LxlVvGXSQlSubK8r0pGf9zf7s/3RHe75a2WlSXQf3gZFR/BtRnR7fCIcaG//CbGfodBFp06DBx/S
9hUV8Bk=`, "NwuwhhRWX8QZ/vhWKWgQ1+rNomI="},
{63, `L+LSB8kmGMnHaWVA5P/+qFnfQliXvgJW7d2JGAgT6+koi5NQujFW1bwQVoXrBVyob/gBxGizUoJM
gid5gGNo`, "ndX/KZBtFoeO3xKeo1ajO/Jy+rY="},
{64, `Mb7EGva2rEE5fENDL85P+BsapHEEjv2/siVhKjvAQe02feExVOQSkfmuYzU/kTF1MaKjPmKF/w+c
bvwfdWL8aQ==`, "n1anP5NfvD4XDYWIeRPW3ZkPv1Y="},
{111, `jyibxJSzO6ZiZ0O1qe3tG/bvIAYssvukh9suIT5wEy1JBINVgPiqdsTW0cOpP0aUfP7mgqLfADkz
I/m/GgCuVhr8oFLrOCoTx1/psBOWwhltCbhUx51Icm9aH8tY4Z3ccU+6BKpYQkLCy0B/A9Zc`, "hZfLIilSITC6N3e3tQ/iSgEzkto="},
{128, `ikwCorI7PKWz17EI50jZCGbV9JU2E8bXVfxNMg5zdmqSZ2NlsQPp0kqYIPjzwTg1MBtfWPg53k0h
0P2naJNEVgrqpoHTfV2b3pJ4m0zYPTJmUX4Bg/lOxcnCxAYKU29Y5F0U8Quz7ZXFBEweftXxJ7RS
4r6N7BzJrPsLhY7hgck=`, "imAoFvCWlDn4yVw3/oq1PDbbm6U="},
{222, `PfxMcUd0vIW6VbHG/uj/Y0W6qEoKmyBD0nYebEKazKaKG+UaDqBEcmQjbfQeVnVLuodMoPp7P7TR
1htX5n2VnkHh22xDyoJ8C/ZQKiSNqQfXvh83judf4RVr9exJCud8Uvgip6aVZTaPrJHVjQhMCp/d
EnGvqg0oN5OVkM2qqAXvA0teKUDhgNM71sDBVBCGXxNOR2bpbD1iM4dnuT0ey4L+loXEHTL0fqMe
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{256, `qwGf2ESubE5jOUHHyc94ORczFYYbc2OmEzo+hBIyzJiNwAzC8PvJqtTzwkWkSslgHFGWQZR2BV5+
uYTrYT7HVwRM40vqfj0dBgeDENyTenIOL1LHkjtDKoXEnQ0mXAHoJ8PjbNC93zi5TovVRXTNzfGE
s5dpWVqxUzb5lc7dwkyvOluBw482mQ4xrzYyIY1t+//OrNi1ObGXuUw2jBQOFfJVj2Y6BOyYmfB1
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mhSrdrtK/CkdU6nDN+34vSR/M8rZpWQdBE7a8g==`, "WYT9JY3JIo/pEBp+tIM6Gt2nyTM="},
{333, `w0LGhqU1WXFbdavqDE4kAjEzWLGGzmTNikzqnsiXHx2KRReKVTxkv27u3UcEz9+lbMvYl4xFf2Z4
aE1xRBBNd1Ke5C0zToSaYw5o4B/7X99nKK2/XaUX1byLow2aju2XJl2OpKpJg+tSJ2fmjIJTkfuY
Uz574dFX6/VXxSxwGH/xQEAKS5TCsBK3CwnuG1p5SAsQq3gGVozDWyjEBcWDMdy8/AIFrj/y03Lf
c/RNRCQTAfZbnf2QwV7sluw4fH3XJr07UoD0YqN+7XZzidtrwqMY26fpLZnyZjnBEt1FAZWO7RnK
G5asg8xRk9YaDdedXdQSJAOy6bWEWlABj+tVAigBxavaluUH8LOj+yfCFldJjNLdi90fVHkUD/m4
Mr5OtmupNMXPwuG3EQlqWUVpQoYpUYKLsk7a5Mvg6UFkiH596y5IbJEVCI1Kb3D1`, "e3+wo77iKcILiZegnzyUNcjCdoQ="},
}
func TestQuickXorHash(t *testing.T) {
for _, test := range testVectors {
what := fmt.Sprintf("test size %d", test.size)
in, err := base64.StdEncoding.DecodeString(test.in)
require.NoError(t, err, what)
got := Sum(in)
want, err := base64.StdEncoding.DecodeString(test.out)
require.NoError(t, err, what)
assert.Equal(t, want, got[:], what)
}
}
func TestQuickXorHashByBlock(t *testing.T) {
for _, blockSize := range []int{1, 2, 4, 7, 8, 16, 32, 64, 128, 256, 512} {
for _, test := range testVectors {
what := fmt.Sprintf("test size %d blockSize %d", test.size, blockSize)
in, err := base64.StdEncoding.DecodeString(test.in)
require.NoError(t, err, what)
h := New()
for i := 0; i < len(in); i += blockSize {
end := i + blockSize
if end > len(in) {
end = len(in)
}
n, err := h.Write(in[i:end])
require.Equal(t, end-i, n, what)
require.NoError(t, err, what)
}
got := h.Sum(nil)
want, err := base64.StdEncoding.DecodeString(test.out)
require.NoError(t, err, what)
assert.Equal(t, want, got[:], test.size, what)
}
}
}
func TestSize(t *testing.T) {
d := New()
assert.Equal(t, 20, d.Size())
}
func TestBlockSize(t *testing.T) {
d := New()
assert.Equal(t, 64, d.BlockSize())
}
func TestReset(t *testing.T) {
d := New()
zeroHash := d.Sum(nil)
_, _ = d.Write([]byte{1})
assert.NotEqual(t, zeroHash, d.Sum(nil))
d.Reset()
assert.Equal(t, zeroHash, d.Sum(nil))
}
// check interface
var _ hash.Hash = (*quickXorHash)(nil)