Mapping for character codes in the private use area (PUA).

Q: we've encountered a PDF file for which Element::GetTextString()
returns character codes in the private use area 0xe000 through 0xe0ff.
PDFNet apparently does this if it encounters unknown glyph names in
the Differences array. Can we safely assume that PDFNet maps code x to
x+0xe000 in that case, so that we can implement the missing glyph
names ourselves?
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A: Yes, this is a correct assumtion. I checked the code and the
output is assigned as '0xE000 + char_code'.