need to handle possible double-bytes?
either into TU codepage specific, or into utf8 (as injson and indxf)
the IS_FROM_TU macro would be also wrong for the first currently implemented case, at least for BIG5, GB2312

* 932 is single-byte for most chars, but 0x8*, 0x9*, 0xE* and 0xF* lead bytes
* CP949, JOHAB, ANSI_949, 936, 950 for all > 0x8* lead bytes
* 1361 for all but 0x8[0123], 0xD[4567F], 0xF[A-F] lead bytes
* BIG5, GB2312 are two-byte only
...

none have valid 0x00 bytes. so it looks like nothing to fix here. 
only logging can be improved to match the current user locale. (UTF-8 or other)
decode pre-r2007 asian codepages
This is a GitHub Issue
repo:libredwg
owner:LibreDWG
Title : decode pre-r2007 asian codepages
Issue date:

--- start body ---
need to handle possible double-bytes?
either into TU codepage specific, or into utf8 (as injson and indxf)
the IS_FROM_TU macro would be also wrong for the first currently implemented case, at least for BIG5, GB2312

* 932 is single-byte for most chars, but 0x8*, 0x9*, 0xE* and 0xF* lead bytes
* CP949, JOHAB, ANSI_949, 936, 950 for all > 0x8* lead bytes
* 1361 for all but 0x8[0123], 0xD[4567F], 0xF[A-F] lead bytes
* BIG5, GB2312 are two-byte only
...

none have valid 0x00 bytes. so it looks like nothing to fix here. 
only logging can be improved to match the current user locale. (UTF-8 or other)
--- end body ---

None