Issue 4127 - [emscripten] Convert subscription classes to C++ - Part 1

compiled/String.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 330 matching lines @@
   {
     if (!sourceLen)
       return;
 
     assert(source, u"Null buffer passed to OwnedString.append()"_str);
     size_t oldLength = length();
     grow(sourceLen);
     std::memcpy(mBuf + oldLength, source, sizeof(value_type) * sourceLen);
   }
 
+  void append(const char* source, size_type sourceLen)
+  {
+    if (!sourceLen)
+      return;
+
+    assert(source, u"Null buffer passed to OwnedString.append()"_str);
+    size_t oldLength = length();
+    grow(sourceLen);
+    for (size_t i = 0; i < sourceLen; i++)
+      mBuf[oldLength + i] = source[i];
+  }
+
   void append(const String& str)
   {
     append(str.mBuf, str.length());
   }
 
   void append(value_type c)
   {
     append(&c, 1);
   }
 };