Re: [Patch] expand,unexpand multibyte support

[Bernhard Voelker]

On 02/18/2013 04:30 PM, Ondrej Oprala wrote:
> Hi, I've been working on multibyte support for the {un,}expand utilities 
> lately, my approach being similar to Padraig's from 2010 ( 
> http://lists.gnu.org/archive/html/coreutils/2010-09/msg00029.html ) . 
> Both tools now read by lines, not bytes, and then iterate over the 
> characters properly.

Thanks - the package maintainer of all distributions will be very happy
once multi-byte support is integrated to all upstream coreutils programs.

I can't tell too much about your patch yet - I even tried to avoid
the umlaut-ö in my own name whenever possible my whole life ;-)
So here are only a few general notes.

I had a bit problems to compile because expand-core.h needs the types
uintmax_t, uint32_t and uint8_t which are not yet defined.
Moving the #include down (in src/{expand,expand-core,unexpand}.c)
worked around this problem, e.g. expand.c:

--- a/src/expand.c
+++ b/src/expand.c
@@ -46,13 +46,13 @@
 # include <unistring/localcharset.h>
 #endif

-#include "expand-core.h"
-
 #include "system.h"
 #include "error.h"
 #include "fadvise.h"
 #include "xstrndup.h"

+#include "expand-core.h"
+
 /* The official name of this program (e.g., no 'g' prefix).  */
 #define PROGRAM_NAME "expand"


In the expand() and unexpand() functions, the variable rawline can
be changed from char** to char*. This makes the code better readable.
I'm not sure whether we should free the rawline buffer on any input
line anyway, because it's filled by getline() and resized as needed;
i.e. reusing malloc'ed space is not a bad thing.

And instead of strdup() without checking, we should use xstrdup():
       {
-        line = (uint8_t *) strdup (*rawline);
+        line = (uint8_t *) xstrdup (rawline);
         clen = 1;
       }
Hopefully, we can avoid that strdup in the final version, and just
use the buffer we already have.

In the tests, please check the exit status of expand/unexpand,
and use our own compare function; e.g. tests/expand/mb.sh:

-expand < in > out
-cmp out exp > /dev/null 2>&1 || fail=1
+expand < in > out || fail=1
+compare exp out || fail=1

It would be good to have much more tests. I have the feeling
that the coverage rate of expand/unexpand wasn't too great
also in the existing tests - though the unexpand test looks
slightly better than the expand test.

Have a nice day,
Berny