-
Notifications
You must be signed in to change notification settings - Fork 2
/
diskable.go
198 lines (164 loc) · 3.53 KB
/
diskable.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
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
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
package fs
import (
"bytes"
"fmt"
"io"
"github.com/chzyer/logex"
)
type Diskable interface {
Magic() Magic
DiskItem
}
type DiskItem interface {
DiskSize() int
ReadDisk([]byte) error
WriteDisk([]byte)
}
type DiskWriteItem interface {
DiskSize() int
WriteDisk([]byte)
}
type DiskReadItem interface {
DiskSize() int
ReadDisk([]byte) error
}
func ReadDisk(r io.ReaderAt, d Diskable, addr Address) error {
buf := make([]byte, d.DiskSize())
_, err := r.ReadAt(buf, int64(addr))
if err != nil {
return logex.Trace(err)
}
return logex.Trace(d.ReadDisk(buf))
}
func WriteDisk(w io.Writer, d Diskable) error {
buf := make([]byte, d.DiskSize())
d.WriteDisk(buf)
_, err := w.Write(buf)
if err != nil {
return logex.Trace(err)
}
return nil
}
func WriteDiskAt(w io.WriterAt, d Diskable, addr Address) error {
buf := make([]byte, d.DiskSize())
d.WriteDisk(buf)
_, err := w.WriteAt(buf, int64(addr))
if err != nil {
return logex.Trace(err)
}
return nil
}
// -----------------------------------------------------------------------------
type DiskBuffer struct {
rw io.ReadWriter
}
func NewDiskBuffer(rw io.ReadWriter) *DiskBuffer {
return &DiskBuffer{rw}
}
func (d *DiskBuffer) ReadItem(da Diskable) error {
buf := make([]byte, da.DiskSize())
if _, err := io.ReadFull(d.rw, buf); err != nil {
return logex.Trace(err)
}
if err := da.ReadDisk(buf); err != nil {
return logex.Trace(err)
}
return nil
}
func (d *DiskBuffer) WriteItem(da Diskable) error {
buf := make([]byte, da.DiskSize())
da.WriteDisk(buf)
n, err := d.rw.Write(buf)
if err != nil {
return logex.Trace(err)
}
if n != len(buf) {
return fmt.Errorf("short written")
}
return nil
}
// -----------------------------------------------------------------------------
type DiskReader struct {
b []byte
offset int
}
func NewDiskReader(b []byte) *DiskReader {
return &DiskReader{b: b}
}
func (r *DiskReader) ReadBytes(n int) []byte {
buf := r.b[r.offset : r.offset+n]
r.offset += n
return buf
}
func (r *DiskReader) ReadItem(d DiskReadItem) error {
n := d.DiskSize()
buf := r.b[r.offset : r.offset+n]
r.offset += n
return d.ReadDisk(buf)
}
func (r *DiskReader) Skip(n int) {
r.offset += n
}
func (r *DiskReader) Peek(n int) []byte {
if n < 0 {
return r.b[r.offset:]
}
return r.b[r.offset : r.offset+n]
}
func (r *DiskReader) ReadItems(ds []DiskReadItem) error {
var err error
for _, d := range ds {
if err = r.ReadItem(d); err != nil {
return err
}
}
return nil
}
func (r *DiskReader) ReadMagic(d Diskable) error {
magic := d.Magic()
magicRead := r.ReadBytes(len(magic))
if !bytes.Equal(magic, magicRead) {
return fmt.Errorf("invalid magic: %v, want: %v",
Magic(magicRead).String(),
magic.String(),
)
}
return nil
}
// -----------------------------------------------------------------------------
type DiskWriter struct {
b []byte
mark int
offset int
}
func NewDiskWriter(b []byte) *DiskWriter {
return &DiskWriter{b: b}
}
func (w *DiskWriter) Mark() {
w.mark = w.offset
}
func (w *DiskWriter) Reset() {
w.offset = w.mark
}
func (w *DiskWriter) Written() int64 {
return int64(w.offset)
}
func (w *DiskWriter) WriteMagic(d Diskable) {
w.WriteBytes(d.Magic())
}
func (w *DiskWriter) WriteBytes(b []byte) {
n := len(b)
nw := copy(w.b[w.offset:], b)
if n != nw {
panic(fmt.Sprintf("not enough memory space: %v", n-nw))
}
w.offset += n
}
func (w *DiskWriter) Skip(n int) {
w.offset += n
}
func (w *DiskWriter) WriteItem(d DiskWriteItem) {
n := d.DiskSize()
d.WriteDisk(w.b[w.offset : w.offset+n])
w.offset += n
}