Moves files

internal/hashing/reader.go

@@ -0,0 +1,29 @@
+package hashing
+
+import (
+	"hash"
+	"io"
+)
+
+// Reader hashes all data read from the underlying reader.
+type Reader struct {
+	r io.Reader
+	h hash.Hash
+}
+
+// NewReader returns a new Reader that uses the hash h.
+func NewReader(r io.Reader, h hash.Hash) *Reader {
+	return &Reader{
+		h: h,
+		r: io.TeeReader(r, h),
+	}
+}
+
+func (h *Reader) Read(p []byte) (int, error) {
+	return h.r.Read(p)
+}
+
+// Sum returns the hash of the data read so far.
+func (h *Reader) Sum(d []byte) []byte {
+	return h.h.Sum(d)
+}