-
Notifications
You must be signed in to change notification settings - Fork 4
/
xxd.go
109 lines (98 loc) · 1.98 KB
/
xxd.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
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
package xxd
import (
"bufio"
"fmt"
"io"
"github.com/google/go-containerregistry/pkg/logs"
)
var (
amp = []byte("&")
lt = []byte("<")
gt = []byte(">")
dq = []byte(""")
sq = []byte("'")
)
func NewWriter(w io.Writer, size int64) *Writer {
return &Writer{
buf: bufio.NewWriter(w),
size: size,
}
}
type Writer struct {
buf *bufio.Writer
size int64
cursor int64
ascii []byte
}
// TODO: restrict to some reasonable number
func (w *Writer) Write(p []byte) (n int, err error) {
left := int(w.cursor % 16)
if left != 0 {
logs.Debug.Printf("left = %d", left)
}
for _, r := range p {
if w.size != 0 && w.cursor >= w.size {
break
}
if w.cursor%16 == 0 {
line := fmt.Sprintf("%08x:", w.cursor)
if _, err := w.buf.WriteString(line); err != nil {
return 0, err
}
w.ascii = []byte{' ', ' '}
}
if w.cursor%2 == 0 {
if err := w.buf.WriteByte(' '); err != nil {
return 0, err
}
}
if r < 32 || r > 126 {
w.ascii = append(w.ascii, '.')
} else {
switch r {
case '&':
w.ascii = append(w.ascii, amp...)
case '<':
w.ascii = append(w.ascii, lt...)
case '>':
w.ascii = append(w.ascii, gt...)
case '"':
w.ascii = append(w.ascii, dq...)
case '\'':
w.ascii = append(w.ascii, sq...)
default:
w.ascii = append(w.ascii, r)
}
}
w.cursor++
line := fmt.Sprintf("%02x", r)
if _, err := w.buf.WriteString(line); err != nil {
return 0, err
}
if w.cursor%16 == 0 {
w.ascii = append(w.ascii, '\n')
if _, err := w.buf.Write(w.ascii); err != nil {
return 0, err
}
}
}
if w.size > 0 && w.cursor >= w.size {
pos := w.size % 16
if pos != 0 {
for i := pos; i < 16; i++ {
if i%2 == 0 {
if err := w.buf.WriteByte(' '); err != nil {
return 0, err
}
}
if _, err := w.buf.Write([]byte(" ")); err != nil {
return 0, err
}
}
if _, err := w.buf.Write(w.ascii); err != nil {
return 0, err
}
}
}
return len(p), w.buf.Flush()
}