1 files changed, 84 insertions, 0 deletions
diff --git a/src/rgw/rgw_b64.h b/src/rgw/rgw_b64.h
new file mode 100644
index 000000000..2948f6f31
--- /dev/null
+++ b/src/rgw/rgw_b64.h
@@ -0,0 +1,84 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab ft=cpp
+
+#pragma once
+
+#include <boost/archive/iterators/base64_from_binary.hpp>
+#include <boost/archive/iterators/binary_from_base64.hpp>
+#include <boost/archive/iterators/insert_linebreaks.hpp>
+#include <boost/archive/iterators/transform_width.hpp>
+#include <boost/archive/iterators/remove_whitespace.hpp>
+#include <limits>
+#include <string>
+#include <string_view>
+
+namespace rgw {
+
+  /*
+   * A header-only Base64 encoder built on boost::archive.  The
+   * formula is based on a class poposed for inclusion in boost in
+   * 2011 by Denis Shevchenko (abandoned), updated slightly
+   * (e.g., uses std::string_view).
+   *
+   * Also, wrap_width added as template argument, based on
+   * feedback from Marcus.
+   */
+
+  template<int wrap_width = std::numeric_limits<int>::max()>
+  inline std::string to_base64(std::string_view sview)
+  {
+    using namespace boost::archive::iterators;
+
+    // output must be =padded modulo 3
+    auto psize = sview.size();
+    while ((psize % 3) != 0) {
+      ++psize;
+    }
+
+    /* RFC 2045 requires linebreaks to be present in the output
+     * sequence every at-most 76 characters (MIME-compliance),
+     * but we could likely omit it. */
+    typedef
+      insert_linebreaks<
+        base64_from_binary<
+          transform_width<
+	    std::string_view::const_iterator
+            ,6,8>
+          >
+          ,wrap_width
+        > b64_iter;
+
+    std::string outstr(b64_iter(sview.data()),
+		       b64_iter(sview.data() + sview.size()));
+
+    // pad outstr with '=' to a length that is a multiple of 3
+    for (size_t ix = 0; ix < (psize-sview.size()); ++ix)
+      outstr.push_back('=');
+
+    return outstr;
+  }
+
+  inline std::string from_base64(std::string_view sview)
+  {
+    using namespace boost::archive::iterators;
+    if (sview.empty())
+      return std::string();
+    /* MIME-compliant input will have line-breaks, so we have to
+     * filter WS */
+    typedef
+      transform_width<
+      binary_from_base64<
+	remove_whitespace<
+	  std::string_view::const_iterator>>
+      ,8,6
+      > b64_iter;
+
+    while (sview.back() == '=')
+      sview.remove_suffix(1);
+
+    std::string outstr(b64_iter(sview.data()),
+		      b64_iter(sview.data() + sview.size()));
+
+    return outstr;
+  }
+} /* namespace */