/
splice.go
86 lines (78 loc) · 1.91 KB
/
splice.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
// Copyright 2018 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package vom
import (
"bytes"
"errors"
"io"
"v.io/v23/vdl"
)
var (
errEncodedBytesNotSupported = errors.New("pre-encoded bytes are not supported by the underlying vom encoder/decoder type")
)
// MergeEncodedBytes represents an already encoded vom stream that is intended
// for use when merging the output of multiple, independent, vom encoders.
type MergeEncodedBytes struct {
Data []byte
}
// VDLWrite implements vdl.Writer.
// Note that it decodes and re-encodes the vom stream and is consequently
// expensive.
func (eb *MergeEncodedBytes) VDLWrite(enc vdl.Encoder) error {
e, ok := enc.(*encoder81)
if !ok {
return errEncodedBytesNotSupported
}
dec := NewDecoder(bytes.NewBuffer(eb.Data))
for {
var any vdl.Value
if err := dec.Decode(&any); err != nil {
if err == io.EOF {
break
}
return err
}
if err := vdl.Write(e, any); err != nil {
return err
}
}
return nil
}
// ExtractEncodedBytes represents an already encoded stream that has been
// extracted from a separate, independent vom stream. NumToDecode controls
// how many values are to be read from the existing stream, or 0 to read
// all values.
type ExtractEncodedBytes struct {
Data []byte
NumToDecode, Decoded int
}
// VDLRead implements vdl.Reader.
func (eb *ExtractEncodedBytes) VDLRead(dec vdl.Decoder) error {
d, ok := dec.(*decoder81)
if !ok {
return errEncodedBytesNotSupported
}
buf := &bytes.Buffer{}
enc := NewEncoder(buf)
n := 0
for {
if eb.NumToDecode > 0 && n == eb.NumToDecode {
break
}
var any vdl.Value
if err := vdl.Read(d, &any); err != nil {
if err == io.EOF {
break
}
return err
}
if err := enc.Encode(any); err != nil {
return err
}
n++
}
eb.Data = buf.Bytes()
eb.Decoded = n
return nil
}