1// Copyright 2023 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5package zstd
6
7import (
8	"bytes"
9	"os"
10	"os/exec"
11	"strconv"
12	"testing"
13)
14
15var xxHashTests = []struct {
16	data string
17	hash uint64
18}{
19	{
20		"hello, world",
21		0xb33a384e6d1b1242,
22	},
23	{
24		"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789$",
25		0x1032d841e824f998,
26	},
27}
28
29func TestXXHash(t *testing.T) {
30	var xh xxhash64
31	for i, test := range xxHashTests {
32		xh.reset()
33		xh.update([]byte(test.data))
34		if got := xh.digest(); got != test.hash {
35			t.Errorf("#%d: got %#x want %#x", i, got, test.hash)
36		}
37	}
38}
39
40func TestLargeXXHash(t *testing.T) {
41	if testing.Short() {
42		t.Skip("skipping expensive test in short mode")
43	}
44
45	data, err := os.ReadFile("../../testdata/Isaac.Newton-Opticks.txt")
46	if err != nil {
47		t.Fatal(err)
48	}
49
50	var xh xxhash64
51	xh.reset()
52	i := 0
53	for i < len(data) {
54		// Write varying amounts to test buffering.
55		c := i%4094 + 1
56		if i+c > len(data) {
57			c = len(data) - i
58		}
59		xh.update(data[i : i+c])
60		i += c
61	}
62
63	got := xh.digest()
64	want := uint64(0xf0dd39fd7e063f82)
65	if got != want {
66		t.Errorf("got %#x want %#x", got, want)
67	}
68}
69
70func findXxhsum(t testing.TB) string {
71	xxhsum, err := exec.LookPath("xxhsum")
72	if err != nil {
73		t.Skip("skipping because xxhsum not found")
74	}
75	return xxhsum
76}
77
78func FuzzXXHash(f *testing.F) {
79	xxhsum := findXxhsum(f)
80
81	for _, test := range xxHashTests {
82		f.Add([]byte(test.data))
83	}
84	f.Add(bytes.Repeat([]byte("abcdefghijklmnop"), 256))
85	var buf bytes.Buffer
86	for i := 0; i < 256; i++ {
87		buf.WriteByte(byte(i))
88	}
89	f.Add(bytes.Repeat(buf.Bytes(), 64))
90	f.Add(bigData(f))
91
92	f.Fuzz(func(t *testing.T, b []byte) {
93		cmd := exec.Command(xxhsum, "-H64")
94		cmd.Stdin = bytes.NewReader(b)
95		var hhsumHash bytes.Buffer
96		cmd.Stdout = &hhsumHash
97		if err := cmd.Run(); err != nil {
98			t.Fatalf("running hhsum failed: %v", err)
99		}
100		hhHashBytes := bytes.Fields(bytes.TrimSpace(hhsumHash.Bytes()))[0]
101		hhHash, err := strconv.ParseUint(string(hhHashBytes), 16, 64)
102		if err != nil {
103			t.Fatalf("could not parse hash %q: %v", hhHashBytes, err)
104		}
105
106		var xh xxhash64
107		xh.reset()
108		xh.update(b)
109		goHash := xh.digest()
110
111		if goHash != hhHash {
112			t.Errorf("Go hash %#x != xxhsum hash %#x", goHash, hhHash)
113		}
114	})
115}
116