Fix base64 decode

libs/utils/src/Base64.cc

@@ -20,6 +20,9 @@
 
 #include "utils/Base64.hh"
 
+#include <algorithm>
+#include <string>
+
 #include <boost/archive/iterators/binary_from_base64.hpp>
 #include <boost/archive/iterators/base64_from_binary.hpp>
 #include <boost/archive/iterators/transform_width.hpp>
@@ -32,8 +35,16 @@ Base64::decode(const std::string &val)
 {
   using namespace boost::archive::iterators;
   using It = transform_width<binary_from_base64<std::string::const_iterator>, 8, 6>;
-  return boost::algorithm::trim_right_copy_if(std::string(It(std::begin(val)), It(std::end(val))),
-                                              [](char c) { return c == '\0'; });
+
+  // pad with '=' if input is not a multiple of 4
+  std::string input = val;
+  input.append(((4 - input.size() % 4) % 4), '=');
+
+  size_t num_padding_chars(std::count(input.begin(), input.end(), '='));
+  std::replace(input.begin(), input.end(), '=', 'A');
+  std::string output(It(input.begin()), It(input.end()));
+  output.erase(output.end() - static_cast<std::string::difference_type>(num_padding_chars), output.end());
+  return output;
 }
 
 std::string

libs/utils/test/UnfoldTestUtils.cc

@@ -34,6 +34,7 @@
 
 #include "utils/Logging.hh"
 #include "utils/StringUtils.hh"
+#include "utils/Base64.hh"
 
 #define BOOST_TEST_MODULE "unfold"
 #include <boost/test/unit_test.hpp>
@@ -114,4 +115,46 @@ BOOST_AUTO_TEST_CASE(utils_empty_string_utf8_to_utf16)
   BOOST_CHECK(s == L"");
 }
 
+BOOST_AUTO_TEST_CASE(utils_base64_encode)
+{
+  std::string s = unfold::utils::Base64::encode("Hello World");
+  BOOST_CHECK_EQUAL(s, "SGVsbG8gV29ybGQ=");
+}
+
+BOOST_AUTO_TEST_CASE(utils_base64_decode)
+{
+  std::string s = unfold::utils::Base64::decode("SGVsbG8gV29ybGQ=");
+  BOOST_CHECK_EQUAL(s, "Hello World");
+}
+
+BOOST_AUTO_TEST_CASE(utils_base64_decode_0_terminated)
+{
+  std::string ref = {'\xe3', '\xeb', '\x54', '\x77', '\x79', '\x46', '\xba', '\x72', '\xfa', '\x85', '\x96', '\x60', '\x02',
+                     '\x31', '\xb5', '\x85', '\xea', '\xe6', '\xaf', '\x8c', '\x43', '\x18', '\xf3', '\x5e', '\xaa', '\x52',
+                     '\x0f', '\x40', '\xfb', '\xdd', '\xe2', '\x4f', '\xdc', '\xdd', '\x4c', '\xad', '\x19', '\x9d', '\x22',
+                     '\x1f', '\xd4', '\x24', '\xb2', '\xbb', '\x2e', '\x27', '\xb3', '\x0d', '\xc3', '\xa5', '\xfc', '\x1c',
+                     '\x76', '\xaf', '\x76', '\x10', '\xb0', '\xc5', '\xed', '\x83', '\x43', '\x3b', '\x55', '\x00'};
+
+  std::string decoded = unfold::utils::Base64::decode(
+    "4+tUd3lGunL6hZZgAjG1hermr4xDGPNeqlIPQPvd4k/c3UytGZ0iH9QksrsuJ7MNw6X8HHavdhCwxe2DQztVAA==");
+
+  BOOST_CHECK_EQUAL(decoded.size(), 64);
+  BOOST_CHECK_EQUAL(decoded, ref);
+}
+
+BOOST_AUTO_TEST_CASE(utils_base64_encode_0_terminated)
+{
+  std::string ref = "4+tUd3lGunL6hZZgAjG1hermr4xDGPNeqlIPQPvd4k/c3UytGZ0iH9QksrsuJ7MNw6X8HHavdhCwxe2DQztVAA==";
+
+  std::string decoded = {'\xe3', '\xeb', '\x54', '\x77', '\x79', '\x46', '\xba', '\x72', '\xfa', '\x85', '\x96', '\x60', '\x02',
+                         '\x31', '\xb5', '\x85', '\xea', '\xe6', '\xaf', '\x8c', '\x43', '\x18', '\xf3', '\x5e', '\xaa', '\x52',
+                         '\x0f', '\x40', '\xfb', '\xdd', '\xe2', '\x4f', '\xdc', '\xdd', '\x4c', '\xad', '\x19', '\x9d', '\x22',
+                         '\x1f', '\xd4', '\x24', '\xb2', '\xbb', '\x2e', '\x27', '\xb3', '\x0d', '\xc3', '\xa5', '\xfc', '\x1c',
+                         '\x76', '\xaf', '\x76', '\x10', '\xb0', '\xc5', '\xed', '\x83', '\x43', '\x3b', '\x55', '\x00'};
+
+  std::string encoded = unfold::utils::Base64::encode(decoded);
+
+  BOOST_CHECK_EQUAL(encoded, ref);
+}
+
 BOOST_AUTO_TEST_SUITE_END()