iconv program produces invalid output

[Bruno Haible <haible at ilog dot fr>]

Hi,

The iconv program, when used to convert to some stateful encoding, produces
incomplete output. This is because it fails to emit the shift sequence needed
to return to the initial state.

Example session:

$ # Use libiconv-0.2. glibc iconv does not support UTF-7 yet.
$ export LD_PRELOAD=/usr/local/lib/libiconv_plug.so
$ hex () {
hexdump -e '"%06.6_ax  " 16/1 "%02X "' -e '"  " 16/1 "%_p" "\n"' "$@"
}
$ printf "Au" | iconv -f UCS-2 -t UTF-7 | hex
000000  2B 51 58                                         +QX

This is incorrect, the correct output would be

000000  2B 51 58 55 2D                                   +QXU-

And indeed it is incomplete UTF-7:

$ printf "Au" | iconv -f UCS-2 -t UTF-7 | iconv -f UTF-7 -t UTF-8
iconv: incomplete character or shift sequence at end of buffer

The fix is to call iconv(cd,NULL,....) at the end.

*** glibc-2.1.1/iconv/iconv_prog.c.bak	Wed Jan 20 18:11:51 1999
--- glibc-2.1.1/iconv/iconv_prog.c	Fri Dec 10 10:21:28 1999
***************
*** 330,337 ****
  	}
  
        if (n != (size_t) -1)
! 	/* Everything is processed.  */
! 	break;
  
        if (errno != E2BIG)
  	{
--- 330,347 ----
  	}
  
        if (n != (size_t) -1)
! 	{
! 	  /* Everything is processed.  */
! 	  if (addr != NULL)
! 	    {
! 	      /* One more round, to return to the initial state.  */
! 	      addr = NULL;
! 	      len = 1;
! 	      continue;
! 	    }
! 	  else
! 	    break;
! 	}
  
        if (errno != E2BIG)
  	{