create a ptrdiff_t offset between the start of an allocation region and
some interesting pointer, so it can be adjusted with this offset after
realloc() returns.
found by GCC 12.
hrs@ says that wctomb(3) has an internal shift state,
if wctomb(3) is called outside of libedit,
the internal state can be changed and causes miscalculate multibyte size.
So in this part, wcrtomb(3) should be used.
wcrtomb(3) requires that shift state is given in the argument.
We always initialize the shift state in ct_enc_width() to keep independent
from outside of libedit.
- The file tokenizer.c no longer uses chartype.h,
so don't include the header.
- The dummy definitions of ct_{de,en}code_string() for the
NARROWCHAR case are only used in history.c, so move them there.
- Now the whole content of chartype.h is for the wide character
case only. So remove the NARROWCHAR ifdef and include the
header only in the wide character case.
- In chartype.h, move ct_encode_char() below the comment explaining it.
- No more need for underscores before ct_{de,en}code_string().
- Make the conversion buffer resize functions private.
They are only called from the decoding and encoding functions
inside chartype.c, and no need can possibly arise to call them
from anywhere else.
Let "el.h" include everything needed for struct editline,
and don't include that stuff multiple times. That also improves
consistency, also avoids circular inclusions, and also makes it
easier to follow what is going on, even though not quite as nice.
But it seems like the best we can do...
Next step: Remove #ifdef'ing in read_char(), in the same style
as we did for setlocale(3) in el.c.
A few remarks are required to explain the choices made.
* On first sight, handling mbrtowc(3) seems a bit less trivial
than handling setlocale(3) because its prototype uses the data
type mbstate_t from <wchar.h>. However, it turns out that
"histedit.h" already includes <wchar.h> unconditionally (i don't
like headers including other headers, but that ship has sailed,
people are by now certainly used to the fact that including
"histedit.h" doesn't require including <wchar.h> before), and
"histedit.h" is of course included all over the place. So from
that perspective, there is no problem with using mbrtowc(3)
unconditionally ever for !WIDECHAR.
* However, <wchar.h> also defines the mbrtowc(3) prototype,
so we cannot just #define mbrtowc away, or including the header
will break. It would also be a bad idea to porovide a local
implementation of mbrtowc() and hope that it overrides the one
in libc. Besides, the required prototype is subtly different:
While mbrtowc(3) takes "wchar_t *" as its first argument, we
need a function that takes "Char *". So unfortunately, we have
to keep a ct_mbrtowc #define, at least until we can maybe get
rid of "Char *" in the more remote future.
* After getting rid of the #else clause in read_char(), we can
pull "return 1;" into the default: clause. After that, we can
get rid of the ugly "goto again_lastbyte;" and just "break;".
As a bonus, that also gets rid of the ugly CONSTCOND.
* While here, delete the unused ct_mbtowc() from chartype.h.
mrg