vendor: add packages

vendor/github.com/pires/go-proxyproto/version_cmd.go

@@ -0,0 +1,39 @@
+package proxyproto
+
+// ProtocolVersionAndCommand represents proxy protocol version and command.
+type ProtocolVersionAndCommand byte
+
+const (
+	LOCAL = '\x20'
+	PROXY = '\x21'
+)
+
+var supportedCommand = map[ProtocolVersionAndCommand]bool{
+	LOCAL: true,
+	PROXY: true,
+}
+
+// IsLocal returns true if the protocol version is \x2 and command is LOCAL, false otherwise.
+func (pvc ProtocolVersionAndCommand) IsLocal() bool {
+	return 0x20 == pvc&0xF0 && 0x00 == pvc&0x0F
+}
+
+// IsProxy returns true if the protocol version is \x2 and command is PROXY, false otherwise.
+func (pvc ProtocolVersionAndCommand) IsProxy() bool {
+	return 0x20 == pvc&0xF0 && 0x01 == pvc&0x0F
+}
+
+// IsUnspec returns true if the protocol version or command is unspecified, false otherwise.
+func (pvc ProtocolVersionAndCommand) IsUnspec() bool {
+	return !(pvc.IsLocal() || pvc.IsProxy())
+}
+
+func (pvc ProtocolVersionAndCommand) toByte() byte {
+	if pvc.IsLocal() {
+		return LOCAL
+	} else if pvc.IsProxy() {
+		return PROXY
+	}
+
+	return LOCAL
+}