use go 1.12

Signed-off-by: hongming <talonwan@yunify.com>

vendor/github.com/lucas-clemente/quic-go/internal/wire/stream_frame.go

@@ -0,0 +1,179 @@
+package wire
+
+import (
+	"bytes"
+	"errors"
+	"io"
+
+	"github.com/lucas-clemente/quic-go/internal/protocol"
+	"github.com/lucas-clemente/quic-go/internal/utils"
+	"github.com/lucas-clemente/quic-go/qerr"
+)
+
+// A StreamFrame of QUIC
+type StreamFrame struct {
+	StreamID       protocol.StreamID
+	FinBit         bool
+	DataLenPresent bool
+	Offset         protocol.ByteCount
+	Data           []byte
+}
+
+// parseStreamFrame reads a STREAM frame
+func parseStreamFrame(r *bytes.Reader, version protocol.VersionNumber) (*StreamFrame, error) {
+	if !version.UsesIETFFrameFormat() {
+		return parseLegacyStreamFrame(r, version)
+	}
+
+	frame := &StreamFrame{}
+
+	typeByte, err := r.ReadByte()
+	if err != nil {
+		return nil, err
+	}
+
+	frame.FinBit = typeByte&0x1 > 0
+	frame.DataLenPresent = typeByte&0x2 > 0
+	hasOffset := typeByte&0x4 > 0
+
+	streamID, err := utils.ReadVarInt(r)
+	if err != nil {
+		return nil, err
+	}
+	frame.StreamID = protocol.StreamID(streamID)
+	if hasOffset {
+		offset, err := utils.ReadVarInt(r)
+		if err != nil {
+			return nil, err
+		}
+		frame.Offset = protocol.ByteCount(offset)
+	}
+
+	var dataLen uint64
+	if frame.DataLenPresent {
+		var err error
+		dataLen, err = utils.ReadVarInt(r)
+		if err != nil {
+			return nil, err
+		}
+		// shortcut to prevent the unnecessary allocation of dataLen bytes
+		// if the dataLen is larger than the remaining length of the packet
+		// reading the packet contents would result in EOF when attempting to READ
+		if dataLen > uint64(r.Len()) {
+			return nil, io.EOF
+		}
+	} else {
+		// The rest of the packet is data
+		dataLen = uint64(r.Len())
+	}
+	if dataLen != 0 {
+		frame.Data = make([]byte, dataLen)
+		if _, err := io.ReadFull(r, frame.Data); err != nil {
+			// this should never happen, since we already checked the dataLen earlier
+			return nil, err
+		}
+	}
+	if frame.Offset+frame.DataLen() > protocol.MaxByteCount {
+		return nil, qerr.Error(qerr.InvalidStreamData, "data overflows maximum offset")
+	}
+	return frame, nil
+}
+
+// Write writes a STREAM frame
+func (f *StreamFrame) Write(b *bytes.Buffer, version protocol.VersionNumber) error {
+	if !version.UsesIETFFrameFormat() {
+		return f.writeLegacy(b, version)
+	}
+
+	if len(f.Data) == 0 && !f.FinBit {
+		return errors.New("StreamFrame: attempting to write empty frame without FIN")
+	}
+
+	typeByte := byte(0x10)
+	if f.FinBit {
+		typeByte ^= 0x1
+	}
+	hasOffset := f.Offset != 0
+	if f.DataLenPresent {
+		typeByte ^= 0x2
+	}
+	if hasOffset {
+		typeByte ^= 0x4
+	}
+	b.WriteByte(typeByte)
+	utils.WriteVarInt(b, uint64(f.StreamID))
+	if hasOffset {
+		utils.WriteVarInt(b, uint64(f.Offset))
+	}
+	if f.DataLenPresent {
+		utils.WriteVarInt(b, uint64(f.DataLen()))
+	}
+	b.Write(f.Data)
+	return nil
+}
+
+// Length returns the total length of the STREAM frame
+func (f *StreamFrame) Length(version protocol.VersionNumber) protocol.ByteCount {
+	if !version.UsesIETFFrameFormat() {
+		return f.lengthLegacy(version)
+	}
+	length := 1 + utils.VarIntLen(uint64(f.StreamID))
+	if f.Offset != 0 {
+		length += utils.VarIntLen(uint64(f.Offset))
+	}
+	if f.DataLenPresent {
+		length += utils.VarIntLen(uint64(f.DataLen()))
+	}
+	return length + f.DataLen()
+}
+
+// MaxDataLen returns the maximum data length
+// If 0 is returned, writing will fail (a STREAM frame must contain at least 1 byte of data).
+func (f *StreamFrame) MaxDataLen(maxSize protocol.ByteCount, version protocol.VersionNumber) protocol.ByteCount {
+	if !version.UsesIETFFrameFormat() {
+		return f.maxDataLenLegacy(maxSize, version)
+	}
+
+	headerLen := 1 + utils.VarIntLen(uint64(f.StreamID))
+	if f.Offset != 0 {
+		headerLen += utils.VarIntLen(uint64(f.Offset))
+	}
+	if f.DataLenPresent {
+		// pretend that the data size will be 1 bytes
+		// if it turns out that varint encoding the length will consume 2 bytes, we need to adjust the data length afterwards
+		headerLen++
+	}
+	if headerLen > maxSize {
+		return 0
+	}
+	maxDataLen := maxSize - headerLen
+	if f.DataLenPresent && utils.VarIntLen(uint64(maxDataLen)) != 1 {
+		maxDataLen--
+	}
+	return maxDataLen
+}
+
+// MaybeSplitOffFrame splits a frame such that it is not bigger than n bytes.
+// If n >= len(frame), nil is returned and nothing is modified.
+func (f *StreamFrame) MaybeSplitOffFrame(maxSize protocol.ByteCount, version protocol.VersionNumber) (*StreamFrame, error) {
+	if maxSize >= f.Length(version) {
+		return nil, nil
+	}
+
+	n := f.MaxDataLen(maxSize, version)
+	if n == 0 {
+		return nil, errors.New("too small")
+	}
+	newFrame := &StreamFrame{
+		FinBit:         false,
+		StreamID:       f.StreamID,
+		Offset:         f.Offset,
+		Data:           f.Data[:n],
+		DataLenPresent: f.DataLenPresent,
+	}
+
+	f.Data = f.Data[n:]
+	f.Offset += n
+
+	return newFrame, nil
+}