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/util.go

@@ -0,0 +1,49 @@
+package util
+
+import (
+	"bytes"
+	"crypto/sha256"
+
+	"io"
+	"io/ioutil"
+)
+
+// Convenience function
+
+// BufferLength returns the length of a buffer as uint32
+func BufferLength(buf *bytes.Buffer) uint32 {
+
+	return uint32(buf.Len())
+}
+
+// SumSHA256 returns the sha256 sum of the data
+func SumSHA256(b []byte) []byte {
+	h := sha256.New()
+	h.Write(b)
+	return h.Sum(nil)
+}
+
+// CalculateHash takes a function with a binary writer and returns
+// the double hash of the io.Writer
+func CalculateHash(f func(bw *BinWriter)) (Uint256, error) {
+	buf := new(bytes.Buffer)
+	bw := &BinWriter{W: buf}
+
+	f(bw)
+
+	var hash Uint256
+	hash = sha256.Sum256(buf.Bytes())
+	hash = sha256.Sum256(hash.Bytes())
+	return hash, bw.Err
+
+}
+
+//ReaderToBuffer converts a io.Reader into a bytes.Buffer
+func ReaderToBuffer(r io.Reader) (*bytes.Buffer, error) {
+	byt, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+	buf := bytes.NewBuffer(byt)
+	return buf, nil
+}