util: io::load accepts base64 encoding without newlines

This commit also renames io::BASE_64 to io::BASE64.

refs #3741

Change-Id: I46286c72d12e685902a72ce8dab4a1385dc0fceb
diff --git a/src/security/transform/strip-space.hpp b/src/security/transform/strip-space.hpp
new file mode 100644
index 0000000..7cc4dc8
--- /dev/null
+++ b/src/security/transform/strip-space.hpp
@@ -0,0 +1,65 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2016 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#ifndef NDN_CXX_SECURITY_TRANSFORM_STRIP_SPACE_HPP
+#define NDN_CXX_SECURITY_TRANSFORM_STRIP_SPACE_HPP
+
+#include "transform-base.hpp"
+#include <bitset>
+#include <climits>
+
+namespace ndn {
+namespace security {
+namespace transform {
+
+/** \brief strip whitespace characters from a stream
+ *
+ *  This transform interprets the input as a byte string, and puts all bytes except
+ *  whitespace characters on the output.
+ */
+class StripSpace : public Transform
+{
+public:
+  static const char* const DEFAULT_WHITESPACES;
+
+  explicit
+  StripSpace(const char* whitespaces = DEFAULT_WHITESPACES);
+
+private:
+  virtual size_t
+  convert(const uint8_t* buf, size_t buflen) final;
+
+private:
+  static constexpr size_t CHARMAP_SIZE = 1 << CHAR_BIT;
+  std::bitset<CHARMAP_SIZE> m_isWhitespace; // char => whether char is whitespace
+};
+
+/** \brief constructs a StripSpace transform
+ *  \param whitespaces characters classified as whitespaces, terminated with null
+ */
+unique_ptr<Transform>
+stripSpace(const char* whitespaces = StripSpace::DEFAULT_WHITESPACES);
+
+} // namespace transform
+} // namespace security
+} // namespace ndn
+
+#endif // NDN_CXX_SECURITY_TRANSFORM_STRIP_SPACE_HPP