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.cpp b/src/security/transform/strip-space.cpp
new file mode 100644
index 0000000..dad2cc3
--- /dev/null
+++ b/src/security/transform/strip-space.cpp
@@ -0,0 +1,62 @@
+/* -*- 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.
+ */
+
+#include "strip-space.hpp"
+
+namespace ndn {
+namespace security {
+namespace transform {
+
+const char* const StripSpace::DEFAULT_WHITESPACES = " \f\n\r\t\v";
+
+StripSpace::StripSpace(const char* whitespaces)
+{
+  for (const char* i = whitespaces; *i != '\0'; ++i) {
+    m_isWhitespace.set(*i);
+  }
+}
+
+size_t
+StripSpace::convert(const uint8_t* buf, size_t buflen)
+{
+  auto buffer = make_unique<OBuffer>();
+  buffer->reserve(buflen);
+
+  for (size_t i = 0; i < buflen; ++i) {
+    uint8_t ch = buf[i];
+    if (!m_isWhitespace[ch]) {
+      buffer->push_back(ch);
+    }
+  }
+
+  setOutputBuffer(std::move(buffer));
+  return buflen;
+}
+
+unique_ptr<Transform>
+stripSpace(const char* whitespaces)
+{
+  return make_unique<StripSpace>(whitespaces);
+}
+
+} // namespace transform
+} // namespace security
+} // namespace ndn