Custom Plugin for Photoshop

I need a custom plugin created that will be a proof of concept for an ongoing project.  I'm looking for a C++ plugin that will simulate certain actions that usually are made be hand, i need all of that to be done by the C++ code. Make sure the code compile able under MacOS and Windows.  Read very carefully the document and let me know what functionality might not be supported by the PhotoShop plugin library.  NOTE: No JavaScript or Macroses are allowed (don't even mention).  Please see the attached document for the exact info.