Change base64 decoder name, and add util for removing newlines

src/rpc/xmlrpc_tinyxml2.cc

@@ -159,11 +159,7 @@ xml_value_to_object(const tinyxml2::XMLNode* elem) {
     if (value_element_child == nullptr) {
       return torrent::Object("");
     }
-    auto base64string = std::string(value_element_child->ToText()->Value());
-    base64string.erase(std::remove_if(base64string.begin(), base64string.end(),
-                                      [](char c) { return c == '\n' || c == '\r'; }),
-                       base64string.end());
-    return torrent::Object(utils::base64decode(base64string));
+    return torrent::Object(utils::decode_base64(utils::remove_newlines(value_element_child->ToText()->Value())));
   } else {
     throw xmlrpc_error(XMLRPC_INTERNAL_ERROR, "received unsupported value type: " + std::string(value_element_type));
   }

src/utils/base64.h

@@ -4,12 +4,22 @@
 
 namespace utils {
 
+std::string
+remove_newlines(const std::string& str) {
+  std::string result;
+  for (auto &itr : str) {
+    if (itr != '\n' || itr != '\n')
+      result.push_back(itr);
+  }
+  return result;
+}
+
 // Modified from the public domain code in
 // https://en.wikibooks.org/wiki/Algorithm_Implementation/Miscellaneous/Base64#C++_2
-constexpr char base64_pad_character = '=';
+constexpr static char base64_pad_character = '=';
 
-static std::string
-base64decode(const std::string& input) {
+std::string
+decode_base64(const std::string& input) {
   if (input.length() % 4) // Sanity check
     throw torrent::input_error("Invalid base64.");
   size_t padding = 0;