bug#29189: 25.3; Dired does not work with binary filenames

[Eli Zaretskii <eliz@gnu.org>]

Ping!  Ping!  I'd _really_ like to fix this for Emacs 26, but I'm
bothered by the potential adverse consequences of making changes in
such a central piece of code.

Still hoping to get comments from Handa-san.

> Date: Fri, 24 Nov 2017 10:52:19 +0200
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: vianchielfaura@gmail.com, 29189@debbugs.gnu.org
> 
> Ping!  Kenichi, any comments on this issue or the proposed patch?
> 
> > Date: Mon, 20 Nov 2017 20:15:55 +0200
> > From: Eli Zaretskii <eliz@gnu.org>
> > Cc: vianchielfaura@gmail.com, 29189@debbugs.gnu.org
> > 
> > > From: Andreas Schwab <schwab@suse.de>
> > > Cc: Kenichi Handa <handa@gnu.org>,  vianchielfaura@gmail.com,  29189@debbugs.gnu.org
> > > Date: Mon, 20 Nov 2017 10:48:09 +0100
> > > 
> > > > +	      /* Copy raw bytes in their 2-byte forms as single characters.  */
> > > > +	      if (CHAR_BYTE8_HEAD_P (*src) && nbytes > 0)
> > > > +		{
> > > > +		  c = STRING_CHAR_ADVANCE (src);
> > > 
> > > CHAR_BYTE8_HEAD_P and STRING_CHAR_ADVANCE are only valid for multibyte
> > > strings.  I don't think it makes sense to use them for unibyte strings.
> > 
> > Right you are, thanks.  Updated patch below.
> > 
> > diff --git a/src/coding.c b/src/coding.c
> > index d790ad0..ac55f87 100644
> > --- a/src/coding.c
> > +++ b/src/coding.c
> > @@ -7423,10 +7423,23 @@ decode_coding (struct coding_system *coding)
> >  
> >  	  while (nbytes-- > 0)
> >  	    {
> > -	      int c = *src++;
> > +	      int c;
> >  
> > -	      if (c & 0x80)
> > -		c = BYTE8_TO_CHAR (c);
> > +	      /* Copy raw bytes in their 2-byte forms from multibyte
> > +		 text as single characters.  */
> > +	      if (coding->src_multibyte
> > +		  && CHAR_BYTE8_HEAD_P (*src) && nbytes > 0)
> > +		{
> > +		  c = STRING_CHAR_ADVANCE (src);
> > +		  nbytes--;
> > +		}
> > +	      else
> > +		{
> > +		  c = *src++;
> > +
> > +		  if (c & 0x80)
> > +		    c = BYTE8_TO_CHAR (c);
> > +		}
> >  	      coding->charbuf[coding->charbuf_used++] = c;
> >  	    }
> >  	  produce_chars (coding, Qnil, 1);
> > 
> > 
> > 
> > 
> 
> 
> 
>