-
Notifications
You must be signed in to change notification settings - Fork 67
/
fielditer.go
70 lines (57 loc) · 1.35 KB
/
fielditer.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
package zed
import (
"errors"
"github.com/brimdata/zed/zcode"
)
var (
ErrExhausted = errors.New("called Next() on iterator after last record")
ErrMismatch = errors.New("mismatch between record type and value")
)
type iterInfo struct {
iter zcode.Iter
typ *TypeRecord
offset int
field []string
}
type fieldIter struct {
stack []iterInfo
}
func (r *fieldIter) Done() bool {
return len(r.stack) == 0
}
func (r *fieldIter) Next() ([]string, Value, error) {
if len(r.stack) == 0 {
return nil, Value{}, ErrExhausted
}
info := &r.stack[len(r.stack)-1]
zv, container, err := info.iter.Next()
if err != nil {
return nil, Value{}, err
}
col := info.typ.Columns[info.offset]
fullname := append(info.field, col.Name)
recType, isRecord := AliasOf(col.Type).(*TypeRecord)
if isRecord {
if !container {
return nil, Value{}, ErrMismatch
}
r.stack = append(r.stack, iterInfo{zv.Iter(), recType, 0, fullname})
return r.Next()
}
// we're at a leaf value, assemble it
val := Value{col.Type, zv}
// and advance our position, stepping out of records as needed.
info.offset++
for info.offset >= len(info.typ.Columns) {
if !info.iter.Done() {
return nil, Value{}, ErrMismatch
}
r.stack = r.stack[:len(r.stack)-1]
if len(r.stack) == 0 {
break
}
info = &r.stack[len(r.stack)-1]
info.offset++
}
return fullname, val, nil
}