Refactor serialization helpers from impl/memory -> service/datastore/serialize

service/datastore/serialize/binary_tools.go

Index: service/datastore/serialize/binary_tools.go
diff --git a/service/datastore/serialize/binary_tools.go b/service/datastore/serialize/binary_tools.go
new file mode 100644
index 0000000000000000000000000000000000000000..38c899e10645e5d2dbeb67592f8c88f09708a2a9
--- /dev/null
+++ b/service/datastore/serialize/binary_tools.go
@@ -0,0 +1,43 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package serialize
+
+import (
+	"bytes"
+)
+
+// Join is a convenience invocation of bytes.Join(itms, nil)
+func Join(itms ...[]byte) []byte {
+	return bytes.Join(itms, nil)
+}
+
+// Invert simply inverts all the bytes in bs.
+func Invert(bs []byte) []byte {
+	if len(bs) == 0 {
+		return nil
+	}
+	ret := make([]byte, len(bs))
+	for i, b := range bs {
+		ret[i] = 0xFF ^ b
+	}
+	return ret
+}
+
+// Increment attempts to increment a copy of bstr as if adding 1 to an integer.
+//
+// If it overflows, the returned []byte will be all 0's, and the overflow bool
+// will be true.
+func Increment(bstr []byte) ([]byte, bool) {
+	ret := Join(bstr)
+	for i := len(ret) - 1; i >= 0; i-- {
+		if ret[i] == 0xFF {
+			ret[i] = 0
+		} else {
+			ret[i]++
+			return ret, false
+		}
+	}
+	return ret, true
+}