move all frames to separate package

frames/stream_frame.go

@@ -0,0 +1,89 @@
+package frames
+
+import (
+	"bytes"
+	"io/ioutil"
+
+	"github.com/lucas-clemente/quic-go/utils"
+)
+
+// A StreamFrame of QUIC
+type StreamFrame struct {
+	FinBit   bool
+	StreamID uint32
+	Offset   uint64
+	Data     []byte
+}
+
+// ParseStreamFrame reads a stream frame. The type byte must not have been read yet.
+func ParseStreamFrame(r *bytes.Reader) (*StreamFrame, error) {
+	frame := &StreamFrame{}
+
+	typeByte, err := r.ReadByte()
+	if err != nil {
+		return nil, err
+	}
+
+	frame.FinBit = typeByte&0x40 > 0
+	dataLenPresent := typeByte&0x20 > 0
+	offsetLen := typeByte & 0x1C >> 2
+	if offsetLen != 0 {
+		offsetLen++
+	}
+	streamIDLen := typeByte&0x03 + 1
+
+	sid, err := utils.ReadUintN(r, streamIDLen)
+	if err != nil {
+		return nil, err
+	}
+	frame.StreamID = uint32(sid)
+
+	frame.Offset, err = utils.ReadUintN(r, offsetLen)
+	if err != nil {
+		return nil, err
+	}
+
+	var dataLen uint16
+	if dataLenPresent {
+		dataLen, err = utils.ReadUint16(r)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if dataLen == 0 {
+		// The rest of the packet is data
+		frame.Data, err = ioutil.ReadAll(r)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		frame.Data = make([]byte, dataLen)
+		if _, err := r.Read(frame.Data); err != nil {
+			return nil, err
+		}
+	}
+
+	return frame, nil
+}
+
+// WriteStreamFrame writes a stream frame.
+func (f *StreamFrame) Write(b *bytes.Buffer) error {
+	typeByte := uint8(0x80)
+	if f.FinBit {
+		typeByte ^= 0x40
+	}
+	typeByte ^= 0x20
+	if f.Offset != 0 {
+		typeByte ^= 0x1c // TODO: Send shorter offset if possible
+	}
+	typeByte ^= 0x03 // TODO: Send shorter stream ID if possible
+	b.WriteByte(typeByte)
+	utils.WriteUint32(b, f.StreamID)
+	if f.Offset != 0 {
+		utils.WriteUint64(b, f.Offset)
+	}
+	utils.WriteUint16(b, uint16(len(f.Data)))
+	b.Write(f.Data)
+	return nil
+}