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
|
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package zlib
import (
"bytes"
"io"
"io/ioutil"
"os"
"testing"
)
var filenames = []string{
"../testdata/e.txt",
"../testdata/pi.txt",
}
// Tests that compressing and then decompressing the given file at the given compression level and dictionary
// yields equivalent bytes to the original file.
func testFileLevelDict(t *testing.T, fn string, level int, d string) {
// Read dictionary, if given.
var dict []byte
if d != "" {
dict = []byte(d)
}
// Read the file, as golden output.
golden, err := os.Open(fn)
if err != nil {
t.Errorf("%s (level=%d, dict=%q): %v", fn, level, d, err)
return
}
defer golden.Close()
// Read the file again, and push it through a pipe that compresses at the write end, and decompresses at the read end.
raw, err := os.Open(fn)
if err != nil {
t.Errorf("%s (level=%d, dict=%q): %v", fn, level, d, err)
return
}
piper, pipew := io.Pipe()
defer piper.Close()
go func() {
defer raw.Close()
defer pipew.Close()
zlibw, err := NewWriterDict(pipew, level, dict)
if err != nil {
t.Errorf("%s (level=%d, dict=%q): %v", fn, level, d, err)
return
}
defer zlibw.Close()
var b [1024]byte
for {
n, err0 := raw.Read(b[0:])
if err0 != nil && err0 != os.EOF {
t.Errorf("%s (level=%d, dict=%q): %v", fn, level, d, err0)
return
}
_, err1 := zlibw.Write(b[0:n])
if err1 == os.EPIPE {
// Fail, but do not report the error, as some other (presumably reportable) error broke the pipe.
return
}
if err1 != nil {
t.Errorf("%s (level=%d, dict=%q): %v", fn, level, d, err1)
return
}
if err0 == os.EOF {
break
}
}
}()
zlibr, err := NewReaderDict(piper, dict)
if err != nil {
t.Errorf("%s (level=%d, dict=%q): %v", fn, level, d, err)
return
}
defer zlibr.Close()
// Compare the two.
b0, err0 := ioutil.ReadAll(golden)
b1, err1 := ioutil.ReadAll(zlibr)
if err0 != nil {
t.Errorf("%s (level=%d, dict=%q): %v", fn, level, d, err0)
return
}
if err1 != nil {
t.Errorf("%s (level=%d, dict=%q): %v", fn, level, d, err1)
return
}
if len(b0) != len(b1) {
t.Errorf("%s (level=%d, dict=%q): length mismatch %d versus %d", fn, level, d, len(b0), len(b1))
return
}
for i := 0; i < len(b0); i++ {
if b0[i] != b1[i] {
t.Errorf("%s (level=%d, dict=%q): mismatch at %d, 0x%02x versus 0x%02x\n", fn, level, d, i, b0[i], b1[i])
return
}
}
}
func TestWriter(t *testing.T) {
for _, fn := range filenames {
testFileLevelDict(t, fn, DefaultCompression, "")
testFileLevelDict(t, fn, NoCompression, "")
for level := BestSpeed; level <= BestCompression; level++ {
testFileLevelDict(t, fn, level, "")
}
}
}
func TestWriterDict(t *testing.T) {
const dictionary = "0123456789."
for _, fn := range filenames {
testFileLevelDict(t, fn, DefaultCompression, dictionary)
testFileLevelDict(t, fn, NoCompression, dictionary)
for level := BestSpeed; level <= BestCompression; level++ {
testFileLevelDict(t, fn, level, dictionary)
}
}
}
func TestWriterDictIsUsed(t *testing.T) {
var input = []byte("Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.")
buf := bytes.NewBuffer(nil)
compressor, err := NewWriterDict(buf, BestCompression, input)
if err != nil {
t.Errorf("error in NewWriterDict: %s", err)
return
}
compressor.Write(input)
compressor.Close()
const expectedMaxSize = 25
output := buf.Bytes()
if len(output) > expectedMaxSize {
t.Errorf("result too large (got %d, want <= %d bytes). Is the dictionary being used?", len(output), expectedMaxSize)
}
}
|
