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
|
/*
* Copyright (c) SAS Institute, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cpio
import (
"fmt"
"io"
)
type file_stream struct {
stream io.ReadSeeker
start_pos int64
curr_pos int64
size int64
}
func newFileStream(stream io.ReadSeeker, size int64) (*file_stream, error) {
pos, err := stream.Seek(0, 1)
if err != nil {
return nil, err
}
return &file_stream{
stream: stream,
start_pos: pos,
curr_pos: 0,
size: size,
}, nil
}
func (fs *file_stream) Read(p []byte) (n int, err error) {
if fs.curr_pos >= fs.size {
return 0, io.EOF
}
pos, err := fs.stream.Seek(0, 1)
if err != nil {
return 0, err
}
if fs.start_pos+fs.curr_pos != pos {
return 0, fmt.Errorf("read out of order")
}
if int64(len(p)) > fs.size-fs.curr_pos {
p = p[0 : fs.size-fs.curr_pos]
}
n, err = fs.stream.Read(p)
fs.curr_pos += int64(n)
return
}
|
