/
tlv.go
52 lines (41 loc) · 859 Bytes
/
tlv.go
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package waclib
import "errors"
type tlvField struct {
Type uint8
Data []byte
}
func tlvUnmarshal(input []byte) ([]tlvField, error) {
var result []tlvField
for {
if len(input) == 0 {
break
}
if len(input) < 2 {
return nil, errors.New("malformed TLV message")
}
fieldLen := int(input[1])
t := input[0]
input = input[2:]
if fieldLen > len(input) {
return nil, errors.New("field truncated")
}
result = append(result, tlvField{
Type: t,
Data: append([]byte{}, input[:fieldLen]...),
})
input = input[fieldLen:]
}
return result, nil
}
func tlvMarshal(fields []tlvField) []byte {
var result []byte
for _, m := range fields {
dl := len(m.Data)
if dl > 255 {
panic("Oversized TLV field")
}
result = append(result, []byte{m.Type, byte(dl)}...)
result = append(result, m.Data...)
}
return result
}