The text console receives bytes that may be UTF-8 encoded (e.g. from
a guest running a modern distro), but currently treats each byte as a
raw character index into the VGA/CP437 font, producing garbled output
for any multi-byte sequence.
Add a UTF-8 decoder using Bjoern Hoehrmann's DFA. The DFA inherently
rejects overlong encodings, surrogates, and codepoints above U+10FFFF.
Completed codepoints are then mapped to CP437, unmappable characters are
displayed as '?'.
Note that QEMU has a "buffered" utf8 decoder in util/unicode.c, but
it is not a good fit for byte-per-byte decoding.
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
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