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package stun
import "errors"
// UnknownAttributes represents UNKNOWN-ATTRIBUTES attribute.
//
// RFC 5389 Section 15.9
type UnknownAttributes []AttrType
func (a UnknownAttributes) String() string {
s := ""
if len(a) == 0 {
return "<nil>"
}
last := len(a) - 1
for i, t := range a {
s += t.String()
if i != last {
s += ", "
}
}
return s
}
// type size is 16 bit.
const attrTypeSize = 4
// AddTo adds UNKNOWN-ATTRIBUTES attribute to message.
func (a UnknownAttributes) AddTo(m *Message) error {
v := make([]byte, 0, attrTypeSize*20) // 20 should be enough
// If len(a.Types) > 20, there will be allocations.
for i, t := range a {
v = append(v, 0, 0, 0, 0) // 4 times by 0 (16 bits)
first := attrTypeSize * i
last := first + attrTypeSize
bin.PutUint16(v[first:last], t.Value())
}
m.Add(AttrUnknownAttributes, v)
return nil
}
// ErrBadUnknownAttrsSize means that UNKNOWN-ATTRIBUTES attribute value
// has invalid length.
var ErrBadUnknownAttrsSize = errors.New("bad UNKNOWN-ATTRIBUTES size")
// GetFrom parses UNKNOWN-ATTRIBUTES from message.
func (a *UnknownAttributes) GetFrom(m *Message) error {
v, err := m.Get(AttrUnknownAttributes)
if err != nil {
return err
}
if len(v)%attrTypeSize != 0 {
return ErrBadUnknownAttrsSize
}
*a = (*a)[:0]
first := 0
for first < len(v) {
last := first + attrTypeSize
*a = append(*a, AttrType(bin.Uint16(v[first:last])))
first = last
}
return nil
}
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