/
compress.go
69 lines (57 loc) · 1.46 KB
/
compress.go
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
package util
import (
"compress/bzip2"
"compress/gzip"
"errors"
"io"
"os"
)
// Decompressor defines an interface to decompress data from io.Reader.
type Decompressor interface {
Decompress(io.Reader) (io.Reader, error)
}
type bzip2Decompressor struct{}
func (d bzip2Decompressor) Decompress(r io.Reader) (io.Reader, error) {
return bzip2.NewReader(r), nil
}
type gzipDecompressor struct{}
func (d gzipDecompressor) Decompress(r io.Reader) (io.Reader, error) {
return gzip.NewReader(r)
}
// NewDecompressor returns a Decompressor for "format".
// If format is not supported, this returns a non-nil error.
func NewDecompressor(format string) (Decompressor, error) {
switch format {
case "bzip2":
return bzip2Decompressor{}, nil
case "gzip":
return gzipDecompressor{}, nil
case "":
return nil, nil
}
return nil, errors.New("unsupported compression format: " + format)
}
// writeToFile copies contents of file at srcPath to destPath,
// optionally decompressing the source contents if decomp is not nil.
func WriteToFile(srcPath, destPath string, decomp Decompressor) error {
f, err := os.Open(srcPath)
if err != nil {
return err
}
defer f.Close()
destFile, err := os.OpenFile(destPath, os.O_WRONLY|os.O_CREATE, 0644)
if err != nil {
return err
}
defer destFile.Close()
var src io.Reader = f
if decomp != nil {
newSrc, err := decomp.Decompress(src)
if err != nil {
return err
}
src = newSrc
}
_, err = io.Copy(destFile, src)
return err
}