In Shift-JIS, Big5 and GBK a double-byte character's trail byte can be 0x5C, the
backslash (表 95 5C, ソ 83 5C, 許 B3 5C, 乗 81 5C). Written as its bytes right
before U+ or M+, the file holds a backslash byte followed by U+, an escape for a
reader that looks for escapes before it decodes the code page. CADCraft decodes
first, so it read back right, but such a character there is now written as a
\U+XXXX escape and the file reads the same either way. Elsewhere it stays as
its bytes. ANSI_949 has no such trail byte.
Suggested by austin62jake on #1693.
crates/dxf/src/lib.rs: #2050's rule (a backslash that would start \U+ or \M+ is
written as \U+005C) goes into push_string, so it holds for UTF-8, code page and
pure ASCII output, the UTF-8 fallback included. A test checks literal escapes
next to code page text in ASCII and binary.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
An ASCII DXF that is valid UTF-8 is read as UTF-8, so pre-2007 text such as
СІ in ANSI_1251 (D1 B2) came back as U+0472. write_ascii_in now falls back to
\U+ escapes for such a file; binary DXF, read by its header's code page,
keeps the bytes. Reported by CodeRabbit on #1693.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
A pre-2007 file whose header says $DWGCODEPAGE ASCII (or UTF8/UNICODE, which
no pre-2007 reader expects) is still written with \U+ escapes only, instead of
Windows-1252 (or UTF-8) bytes the header doesn't declare. Review of #1693.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Before 2007, DXF text is in the code page `$DWGCODEPAGE` names. Since #169
every non-ASCII character was written as a `\U+XXXX` escape, so a Portuguese
drawing saved at 2000/2004 had layers, blocks and text such as
`A\U+00E7\U+00E3o` in the file. Characters the declared code page has are now
written as its bytes (`Ação` in ANSI_1252); the others are still escaped, and
an unknown code page still gives pure ASCII. The DWG bridge is unchanged.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
ffishman