pkg: hide it by moving to _pkg.dev

The idea here is to preserve the history of `dev` branch development and its
code when merging with the `master`. Later this code could be moved into the
masters code where appropriate.

_pkg.dev/wire/util/binaryWriter.go

@@ -0,0 +1,75 @@
+package util
+
+import (
+	"encoding/binary"
+	"errors"
+	"io"
+)
+
+//BinWriter is a convenient wrapper around a io.Writer and err object
+// Used to simplify error handling when writing into a io.Writer
+// from a struct with many fields
+type BinWriter struct {
+	W   io.Writer
+	Err error
+}
+
+// Write writes into the underlying io.Writer from an object v in LE format
+func (w *BinWriter) Write(v interface{}) {
+	if w.Err != nil {
+		return
+	}
+	w.Err = binary.Write(w.W, binary.LittleEndian, v)
+}
+
+// WriteBigEnd writes into the underlying io.Writer from an object v in BE format
+// Only used for IP and PORT. Additional method makes the default LittleEndian case clean
+func (w *BinWriter) WriteBigEnd(v interface{}) {
+	if w.Err != nil {
+		return
+	}
+	w.Err = binary.Write(w.W, binary.BigEndian, v)
+}
+
+// VarUint writes a uint64 into the underlying writer
+func (w *BinWriter) VarUint(val uint64) {
+	if val < 0 {
+		w.Err = errors.New("value out of range")
+		return
+	}
+
+	if w.Err != nil {
+		return
+	}
+
+	if val < 0xfd {
+		w.Err = binary.Write(w.W, binary.LittleEndian, uint8(val))
+		return
+	}
+	if val < 0xFFFF {
+		w.Err = binary.Write(w.W, binary.LittleEndian, byte(0xfd))
+		w.Err = binary.Write(w.W, binary.LittleEndian, uint16(val))
+		return
+	}
+	if val < 0xFFFFFFFF {
+		w.Err = binary.Write(w.W, binary.LittleEndian, byte(0xfe))
+		w.Err = binary.Write(w.W, binary.LittleEndian, uint32(val))
+		return
+
+	}
+
+	w.Err = binary.Write(w.W, binary.LittleEndian, byte(0xff))
+	w.Err = binary.Write(w.W, binary.LittleEndian, val)
+
+}
+
+// VarBytes writes a variable length byte array into the underlying io.Writer
+func (w *BinWriter) VarBytes(b []byte) {
+	w.VarUint(uint64(len(b)))
+	w.Write(b)
+}
+
+//VarString casts the string as a byte slice and calls VarBytes
+func (w *BinWriter) VarString(s string) {
+	w.VarBytes([]byte(s))
+}