normalize file names (#173)

pkg/base/interleaved_frame.go

@@ -0,0 +1,75 @@
+package base
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+)
+
+const (
+	// InterleavedFrameMagicByte is the first byte of an interleaved frame.
+	InterleavedFrameMagicByte = 0x24
+)
+
+// InterleavedFrame is an interleaved frame, and allows to transfer binary data
+// within RTSP/TCP connections. It is used to send and receive RTP and RTCP packets with TCP.
+type InterleavedFrame struct {
+	// channel ID
+	Channel int
+
+	// payload
+	Payload []byte
+}
+
+// Read decodes an interleaved frame.
+func (f *InterleavedFrame) Read(br *bufio.Reader) error {
+	var header [4]byte
+	_, err := io.ReadFull(br, header[:])
+	if err != nil {
+		return err
+	}
+
+	if header[0] != InterleavedFrameMagicByte {
+		return fmt.Errorf("invalid magic byte (0x%.2x)", header[0])
+	}
+
+	// it's useless to check payloadLen since it's limited to 65535
+	payloadLen := int(uint16(header[2])<<8 | uint16(header[3]))
+
+	f.Channel = int(header[1])
+	f.Payload = make([]byte, payloadLen)
+
+	_, err = io.ReadFull(br, f.Payload)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// MarshalSize returns the size of an InterleavedFrame.
+func (f InterleavedFrame) MarshalSize() int {
+	return 4 + len(f.Payload)
+}
+
+// MarshalTo writes an InterleavedFrame.
+func (f InterleavedFrame) MarshalTo(buf []byte) (int, error) {
+	pos := 0
+
+	pos += copy(buf[pos:], []byte{0x24, byte(f.Channel)})
+
+	payloadLen := len(f.Payload)
+	buf[pos] = byte(payloadLen >> 8)
+	buf[pos+1] = byte(payloadLen)
+	pos += 2
+
+	pos += copy(buf[pos:], f.Payload)
+
+	return pos, nil
+}
+
+// Marshal writes an InterleavedFrame.
+func (f InterleavedFrame) Marshal() ([]byte, error) {
+	buf := make([]byte, f.MarshalSize())
+	_, err := f.MarshalTo(buf)
+	return buf, err
+}