if(NOT DEFINED ASN1C_OUTPUT_DIR)
    message(FATAL_ERROR "Missing ASN.1 output directory (ASN1C_OUTPUT_DIR)")
elseif(NOT DEFINED ASN1C_PREFIX)
    message(FATAL_ERROR "Missing ASN.1 prefix (ASN1C_PREFIX)")
endif()

message(STATUS "removing prefix '${ASN1C_PREFIX}' from files in ${ASN1C_OUTPUT_DIR}")
file(GLOB _files ${ASN1C_OUTPUT_DIR}/${ASN1C_PREFIX}*)
foreach(_from ${_files})
    get_filename_component(_dir ${_from} DIRECTORY)
    get_filename_component(_name ${_from} NAME)
    string(REPLACE "${ASN1C_PREFIX}" "" _to "${_name}")
    file(RENAME ${_from} ${_dir}/${_to})
endforeach()