Function wireReadHeaderTrace

lib/wire.go:1074–1195

wireReadHeaderTrace extracts protocol buffer and binary lengths with optional verbose debugging output

(version byte, header []byte, trace bool)

// wireReadHeaderTrace extracts protocol buffer and binary lengths with optional verbose debugging output
func wireReadHeaderTrace(version byte, header []byte, trace bool) (protobufLength int64, binaryLength int64, err error) {
	if trace {
		fmt.Printf("  wireReadHeader: version=%d, header len=%d\n", version, len(header))
		if len(header) > 0 {
			fmt.Printf("    Header bytes: % x\n", header)
		}
	}

	var isValidVersion bool

	switch version {

	// 1 byte version == 0
	// 0 byte protobuf length
	// 0 byte binary length
	// 0 bytes protobuf
	// 0 bytes binary
	case 0:
		protobufLength = 0
		binaryLength = 0
		isValidVersion = true
		if trace {
			fmt.Printf("    Version 0: no data\n")
		}

		// 1 byte version == 1
		// 1 byte protobuf length
		// 1 byte binary length
		// N bytes protobuf
		// N bytes binary
	case 1:
		protobufLength = int64(header[0])
		binaryLength = int64(header[1])
		isValidVersion = true
		if trace {
			fmt.Printf("    Version 1: protobuf=%d, binary=%d\n", protobufLength, binaryLength)
		}

		// 1 byte version == 2
		// 1 byte protobuf length
		// 2 byte binary length
		// N bytes protobuf
		// N bytes binary
	case 2:
		protobufLength = int64(header[0])
		binaryLength = (int64(header[2]) << 8) | int64(header[1])
		isValidVersion = true
		if trace {
			fmt.Printf("    Version 2: protobuf=%d, binary=%d (16-bit)\n", protobufLength, binaryLength)
		}

		// 1 byte version == 3
		// 2 byte protobuf length
		// 2 byte binary length
		// N bytes protobuf
		// N bytes binary
	case 3:
		protobufLength = (int64(header[1]) << 8) | int64(header[0])