forked from quic-go/quic-go
/
capsule.go
55 lines (48 loc) · 1.28 KB
/
capsule.go
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package http3
import (
"io"
"github.com/TugasAkhir-QUIC/quic-go/quicvarint"
)
// CapsuleType is the type of the capsule.
type CapsuleType uint64
type exactReader struct {
R *io.LimitedReader
}
func (r *exactReader) Read(b []byte) (int, error) {
n, err := r.R.Read(b)
if r.R.N > 0 {
return n, io.ErrUnexpectedEOF
}
return n, err
}
// ParseCapsule parses the header of a Capsule.
// It returns an io.LimitedReader that can be used to read the Capsule value.
// The Capsule value must be read entirely (i.e. until the io.EOF) before using r again.
func ParseCapsule(r quicvarint.Reader) (CapsuleType, io.Reader, error) {
ct, err := quicvarint.Read(r)
if err != nil {
if err == io.EOF {
return 0, nil, io.ErrUnexpectedEOF
}
return 0, nil, err
}
l, err := quicvarint.Read(r)
if err != nil {
if err == io.EOF {
return 0, nil, io.ErrUnexpectedEOF
}
return 0, nil, err
}
return CapsuleType(ct), &exactReader{R: io.LimitReader(r, int64(l)).(*io.LimitedReader)}, nil
}
// WriteCapsule writes a capsule
func WriteCapsule(w quicvarint.Writer, ct CapsuleType, value []byte) error {
b := make([]byte, 0, 16)
b = quicvarint.Append(b, uint64(ct))
b = quicvarint.Append(b, uint64(len(value)))
if _, err := w.Write(b); err != nil {
return err
}
_, err := w.Write(value)
return err
}