blob: cd59d727c1c25d224606bb1c5f4953fa3594eae6 (
plain)
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
|
package rifs
import (
"io"
"os"
"github.com/dsoprea/go-logging"
)
// SeekType is a convenience type to associate the different seek-types with
// printable descriptions.
type SeekType int
// String returns a descriptive string.
func (n SeekType) String() string {
if n == io.SeekCurrent {
return "SEEK-CURRENT"
} else if n == io.SeekEnd {
return "SEEK-END"
} else if n == io.SeekStart {
return "SEEK-START"
}
log.Panicf("unknown seek-type: (%d)", n)
return ""
}
// CalculateSeek calculates an offset in a file-stream given the parameters.
func CalculateSeek(currentOffset int64, delta int64, whence int, fileSize int64) (finalOffset int64, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
finalOffset = 0
}
}()
if whence == os.SEEK_SET {
finalOffset = delta
} else if whence == os.SEEK_CUR {
finalOffset = currentOffset + delta
} else if whence == os.SEEK_END {
finalOffset = fileSize + delta
} else {
log.Panicf("whence not valid: (%d)", whence)
}
if finalOffset < 0 {
finalOffset = 0
}
return finalOffset, nil
}
|
