1 files changed, 140 insertions, 0 deletions
diff --git a/vendor/github.com/pion/rtcp/header.go b/vendor/github.com/pion/rtcp/header.go
new file mode 100644
index 0000000..055ca18
--- /dev/null
+++ b/vendor/github.com/pion/rtcp/header.go
@@ -0,0 +1,140 @@
+package rtcp
+
+import (
+	"encoding/binary"
+)
+
+// PacketType specifies the type of an RTCP packet
+type PacketType uint8
+
+// RTCP packet types registered with IANA. See: https://www.iana.org/assignments/rtp-parameters/rtp-parameters.xhtml#rtp-parameters-4
+const (
+	TypeSenderReport              PacketType = 200 // RFC 3550, 6.4.1
+	TypeReceiverReport            PacketType = 201 // RFC 3550, 6.4.2
+	TypeSourceDescription         PacketType = 202 // RFC 3550, 6.5
+	TypeGoodbye                   PacketType = 203 // RFC 3550, 6.6
+	TypeApplicationDefined        PacketType = 204 // RFC 3550, 6.7 (unimplemented)
+	TypeTransportSpecificFeedback PacketType = 205 // RFC 4585, 6051
+	TypePayloadSpecificFeedback   PacketType = 206 // RFC 4585, 6.3
+
+)
+
+// Transport and Payload specific feedback messages overload the count field to act as a message type. those are listed here
+const (
+	FormatSLI  uint8 = 2
+	FormatPLI  uint8 = 1
+	FormatFIR  uint8 = 4
+	FormatTLN  uint8 = 1
+	FormatRRR  uint8 = 5
+	FormatREMB uint8 = 15
+
+	//https://tools.ietf.org/html/draft-holmer-rmcat-transport-wide-cc-extensions-01#page-5
+	FormatTCC uint8 = 15
+)
+
+func (p PacketType) String() string {
+	switch p {
+	case TypeSenderReport:
+		return "SR"
+	case TypeReceiverReport:
+		return "RR"
+	case TypeSourceDescription:
+		return "SDES"
+	case TypeGoodbye:
+		return "BYE"
+	case TypeApplicationDefined:
+		return "APP"
+	case TypeTransportSpecificFeedback:
+		return "TSFB"
+	case TypePayloadSpecificFeedback:
+		return "PSFB"
+	default:
+		return string(p)
+	}
+}
+
+const rtpVersion = 2
+
+// A Header is the common header shared by all RTCP packets
+type Header struct {
+	// If the padding bit is set, this individual RTCP packet contains
+	// some additional padding octets at the end which are not part of
+	// the control information but are included in the length field.
+	Padding bool
+	// The number of reception reports, sources contained or FMT in this packet (depending on the Type)
+	Count uint8
+	// The RTCP packet type for this packet
+	Type PacketType
+	// The length of this RTCP packet in 32-bit words minus one,
+	// including the header and any padding.
+	Length uint16
+}
+
+const (
+	headerLength = 4
+	versionShift = 6
+	versionMask  = 0x3
+	paddingShift = 5
+	paddingMask  = 0x1
+	countShift   = 0
+	countMask    = 0x1f
+	countMax     = (1 << 5) - 1
+)
+
+// Marshal encodes the Header in binary
+func (h Header) Marshal() ([]byte, error) {
+	/*
+	 *  0                   1                   2                   3
+	 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 * |V=2|P|    RC   |   PT=SR=200   |             length            |
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 */
+	rawPacket := make([]byte, headerLength)
+
+	rawPacket[0] |= rtpVersion << versionShift
+
+	if h.Padding {
+		rawPacket[0] |= 1 << paddingShift
+	}
+
+	if h.Count > 31 {
+		return nil, errInvalidHeader
+	}
+	rawPacket[0] |= h.Count << countShift
+
+	rawPacket[1] = uint8(h.Type)
+
+	binary.BigEndian.PutUint16(rawPacket[2:], h.Length)
+
+	return rawPacket, nil
+}
+
+// Unmarshal decodes the Header from binary
+func (h *Header) Unmarshal(rawPacket []byte) error {
+	if len(rawPacket) < headerLength {
+		return errPacketTooShort
+	}
+
+	/*
+	 *  0                   1                   2                   3
+	 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 * |V=2|P|    RC   |      PT       |             length            |
+	 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+	 */
+
+	version := rawPacket[0] >> versionShift & versionMask
+	if version != rtpVersion {
+		return errBadVersion
+	}
+
+	h.Padding = (rawPacket[0] >> paddingShift & paddingMask) > 0
+	h.Count = rawPacket[0] >> countShift & countMask
+
+	h.Type = PacketType(rawPacket[1])
+
+	h.Length = binary.BigEndian.Uint16(rawPacket[2:])
+
+	return nil
+}