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tlv_writer.go
100 lines (92 loc) · 2.02 KB
/
tlv_writer.go
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package bertlv
import (
"bytes"
"encoding/base64"
"errors"
"fmt"
"io"
)
func (tlv *TLV) Len() int {
n := contentLength(tlv)
if n < 128 {
n += 1
} else if n < 256 {
n += 2
} else {
n += 3
}
n += len(tlv.Tag)
return n
}
func (tlv *TLV) WriteTo(w io.Writer) (n int64, err error) {
w = &countWriter{Writer: w, Written: &n}
length := contentLength(tlv)
switch {
case len(tlv.Value) > 0 && tlv.Tag.Constructed():
return 0, errors.New("tlv: constructed tag cannot have value")
case len(tlv.Children) > 0 && tlv.Tag.Primitive():
return 0, errors.New("tlv: primitive tag cannot have children")
case length > 0xffff:
return 0, fmt.Errorf("tlv: length exceeds maximum (%d), got %d", 0xffff, length)
}
if _, err = w.Write(tlv.Tag); err != nil {
return
}
if _, err = w.Write(marshalLength(uint16(length))); err != nil {
return
}
if tlv.Tag.Primitive() {
_, err = w.Write(tlv.Value)
return
}
for _, child := range tlv.Children {
if child == nil {
continue
}
if _, err = child.WriteTo(w); err != nil {
return
}
}
return
}
func (tlv *TLV) MarshalText() ([]byte, error) {
var buf bytes.Buffer
encoder := base64.NewEncoder(base64.StdEncoding, &buf)
_, err := tlv.WriteTo(encoder)
_ = encoder.Close()
return buf.Bytes(), err
}
func (tlv *TLV) MarshalBinary() ([]byte, error) {
var buf bytes.Buffer
buf.Grow(tlv.Len())
_, err := tlv.WriteTo(&buf)
return buf.Bytes(), err
}
func (tlv *TLV) MarshalBERTLV() (*TLV, error) {
return tlv.Clone(), nil
}
func (tlv *TLV) Clone() *TLV {
var cloned TLV
cloned.Tag = make(Tag, len(tlv.Tag))
copy(cloned.Tag, tlv.Tag)
if tlv.Tag.Primitive() {
cloned.Value = make([]byte, len(tlv.Value))
copy(cloned.Value, tlv.Value)
return &cloned
}
cloned.Children = make([]*TLV, 0, len(tlv.Children))
for _, child := range tlv.Children {
if child == nil {
continue
}
cloned.Children = append(cloned.Children, child.Clone())
}
return &cloned
}
func (tlv *TLV) Bytes() []byte {
encoded, err := tlv.MarshalBinary()
if err != nil {
panic(err)
}
return encoded
}