nats: Add support of NATS.io Streaming server (#3494)

vendor/github.com/nats-io/go-nats/encoders/builtin/default_enc.go

@@ -0,0 +1,106 @@
+// Copyright 2012-2015 Apcera Inc. All rights reserved.
+
+package builtin
+
+import (
+	"bytes"
+	"fmt"
+	"reflect"
+	"strconv"
+	"unsafe"
+)
+
+// DefaultEncoder implementation for EncodedConn.
+// This encoder will leave []byte and string untouched, but will attempt to
+// turn numbers into appropriate strings that can be decoded. It will also
+// propely encoded and decode bools. If will encode a struct, but if you want
+// to properly handle structures you should use JsonEncoder.
+type DefaultEncoder struct {
+	// Empty
+}
+
+var trueB = []byte("true")
+var falseB = []byte("false")
+var nilB = []byte("")
+
+// Encode
+func (je *DefaultEncoder) Encode(subject string, v interface{}) ([]byte, error) {
+	switch arg := v.(type) {
+	case string:
+		bytes := *(*[]byte)(unsafe.Pointer(&arg))
+		return bytes, nil
+	case []byte:
+		return arg, nil
+	case bool:
+		if arg {
+			return trueB, nil
+		} else {
+			return falseB, nil
+		}
+	case nil:
+		return nilB, nil
+	default:
+		var buf bytes.Buffer
+		fmt.Fprintf(&buf, "%+v", arg)
+		return buf.Bytes(), nil
+	}
+}
+
+// Decode
+func (je *DefaultEncoder) Decode(subject string, data []byte, vPtr interface{}) error {
+	// Figure out what it's pointing to...
+	sData := *(*string)(unsafe.Pointer(&data))
+	switch arg := vPtr.(type) {
+	case *string:
+		*arg = sData
+		return nil
+	case *[]byte:
+		*arg = data
+		return nil
+	case *int:
+		n, err := strconv.ParseInt(sData, 10, 64)
+		if err != nil {
+			return err
+		}
+		*arg = int(n)
+		return nil
+	case *int32:
+		n, err := strconv.ParseInt(sData, 10, 64)
+		if err != nil {
+			return err
+		}
+		*arg = int32(n)
+		return nil
+	case *int64:
+		n, err := strconv.ParseInt(sData, 10, 64)
+		if err != nil {
+			return err
+		}
+		*arg = int64(n)
+		return nil
+	case *float32:
+		n, err := strconv.ParseFloat(sData, 32)
+		if err != nil {
+			return err
+		}
+		*arg = float32(n)
+		return nil
+	case *float64:
+		n, err := strconv.ParseFloat(sData, 64)
+		if err != nil {
+			return err
+		}
+		*arg = float64(n)
+		return nil
+	case *bool:
+		b, err := strconv.ParseBool(sData)
+		if err != nil {
+			return err
+		}
+		*arg = b
+		return nil
+	default:
+		vt := reflect.TypeOf(arg).Elem()
+		return fmt.Errorf("nats: Default Encoder can't decode to type %s", vt)
+	}
+}