implement the MAX_DATA and MAX_STREAM_DATA frames

For gQUIC WINDOW_UPDATEs are converted to MAX_DATA and MAX_STREAM_DATA,
respectively.

internal/wire/max_stream_data_frame.go

@@ -0,0 +1,56 @@
+package wire
+
+import (
+	"bytes"
+
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/utils"
+)
+
+// A MaxStreamDataFrame carries flow control information for a stream
+type MaxStreamDataFrame struct {
+	StreamID   protocol.StreamID
+	ByteOffset protocol.ByteCount
+}
+
+// ParseMaxStreamDataFrame parses a MAX_STREAM_DATA frame
+func ParseMaxStreamDataFrame(r *bytes.Reader, version protocol.VersionNumber) (*MaxStreamDataFrame, error) {
+	frame := &MaxStreamDataFrame{}
+
+	// read the TypeByte
+	if _, err := r.ReadByte(); err != nil {
+		return nil, err
+	}
+
+	sid, err := utils.GetByteOrder(version).ReadUint32(r)
+	if err != nil {
+		return nil, err
+	}
+	frame.StreamID = protocol.StreamID(sid)
+
+	byteOffset, err := utils.GetByteOrder(version).ReadUint64(r)
+	if err != nil {
+		return nil, err
+	}
+	frame.ByteOffset = protocol.ByteCount(byteOffset)
+	return frame, nil
+}
+
+// Write writes a MAX_STREAM_DATA frame
+func (f *MaxStreamDataFrame) Write(b *bytes.Buffer, version protocol.VersionNumber) error {
+	if !version.UsesMaxDataFrame() {
+		return (&windowUpdateFrame{
+			StreamID:   f.StreamID,
+			ByteOffset: f.ByteOffset,
+		}).Write(b, version)
+	}
+	b.WriteByte(0x5)
+	utils.GetByteOrder(version).WriteUint32(b, uint32(f.StreamID))
+	utils.GetByteOrder(version).WriteUint64(b, uint64(f.ByteOffset))
+	return nil
+}
+
+// MinLength of a written frame
+func (f *MaxStreamDataFrame) MinLength(version protocol.VersionNumber) (protocol.ByteCount, error) {
+	return 1 + 4 + 8, nil
+}