As of Oniguruma 6.8.1, the regex structure has been moved from the
public `oniguruma.h` to the private `regint.h`. Thus, it is no longer
possible to directly access the struct's members, and actually, there
is no need to, since there are respective accessor functions available
at least of 2.3.1.
Instead of returning the encoding of the current substitution
character. This allows a robust check for the failure case. The
substitution character (especially the default of "?") is also
a valid output of mb_chr() for a valid input (for "?" that would be
0x3f), so it's a bad choice for an error value.
Previously mb_chr() had two different encoding-dependent behaviors:
* For "Unicode-encodings" it took a Unicode codepoint and returned
its encoded representation.
* Otherwise it returned a big-endian binary encoding of the passed
integer.
Now the input is always interpreted as a Unicode codepoint. If
a big-endian binary encoding is what you want, you don't need
mbstring to implement that.
The introduced checks were not correct in two respects:
* It was checked whether the source encoding of the string matches
the internal encoding, while the actually relevant encoding is
the *target* encoding.
* Even if the correct encoding is used, the checks are still too
conservative. Just because something is not a "Unicode-encoding"
does not mean that it does not map any non-ASCII characters.
I've reverted the added checks and instead adjusted mbfl_convert
to first try to use the provided substitution character and if
that fails, perform the fallback to '?' at that point. This means
that any codepoint mapped in the target encoding should now be
correctly supported and anything else should fall back to '?'.
The introduced checks did not treat "non-Unicode" encodings correctly,
because they treated the passed integer as encoded in the internal
encoding in that case, while in actuality the substitute character
is always a Unicode codepoint.
Additionally checking the codepoint against the internal encoding
is not correct in any case, because the substitution character must
be mapped in the *target* encoding of the conversion, which does
not necessarily coincide with the internal encoding (the internal
encoding is the default *source* encoding, not *target* encoding).
This reverts the checks back to simple range checks, but in a way
that still resolves#69079: Characters outside the Basic
Multilingual Plane are now accepted and Surrogate Codepoints are
rejected. A distinction between UTF-8 and non-UTF-8 encodings is
not made for surrogate checks (as in the original patch), as
surrogates are always illegal on their own. Specifying a surrogate
as substitution character would only make sense if you could
specify a substitution string with more than one character --
however we do not support that.
ucgendat.c was assuming that a title-case character is a character
that has both lower and upper-case variants. However, there are
title-case characters that only have a lower-case variant. Use the
Lt general character proprety to determine where in the case map
the character should be placed instead.
mb_strtoupper() was converting lowercase characters into
titlecase characters, instead of uppercase characters. Luckily
there are only very few characters with a distinct titlecase
representation, so this mostly worked out okay...
The HTML decoding filter uses the `opaque` member of mbfl_convert_filter
as buffer, but there was no copy constructor defined, what caused double
frees when the filter is copied (what happens multiple times in mb_strcut(),
for instance).
