Re: [HACKERS] Automatic detection of client encoding

2003-05-29 Thread Tatsuo Ishii
I strongly object this idea. We already have had enough trouble with
initdb because of its locale awareness (I still think we should turn
on the --no-locale switch by default).
--
Tatsuo Ishii

 It is a common problem that a server uses a nontrivial character set
 encoding (e.g., Unicode) but users forget to set an appropriate
 client-side encoding.  Then they get bogus displays for non-ASCII
 characters because their client isn't actually prepared for Unicode.
 
 There is a standard interface (SUSv2) for detecting the character set
 based on the locale settings.  I suggest we use this (if available) in
 applications like psql and pg_dump by default unless it is overridden by
 the usual mechanisms.  If the character set name obtained this way is not
 recognized by PostgreSQL, we fall back to SQL_ASCII.
 
 Here's a piece of code that shows how this would work:
 
 #include stdio.h
 #include locale.h
 #include langinfo.h
 
 int
 main(int argc, char *argv[])
 {
 setlocale(LC_ALL, );
 printf(%s\n, nl_langinfo(CODESET));
 return 0;
 }
 
 (LC_CTYPE is the governing category for this.)
 
 Comments?
 
 -- 
 Peter Eisentraut   [EMAIL PROTECTED]
 
 
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Re: [HACKERS] Automatic detection of client encoding

2003-05-29 Thread Tom Lane
Peter Eisentraut [EMAIL PROTECTED] writes:
 There is a standard interface (SUSv2) for detecting the character set
 based on the locale settings.

Hmm.  How trustworthy is that really?

If it works, great, but I wonder if we wouldn't be chasing a
will-o-the=wisp.  My impression is that LC_xxx settings tend to get
inherited from system files that have little to do with what the
individual user (thinks he) is doing :=(

regards, tom lane

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Re: [HACKERS] Automatic detection of client encoding

2003-05-29 Thread Karel Zak
On Wed, May 28, 2003 at 11:56:07PM +0200, Peter Eisentraut wrote:
 There is a standard interface (SUSv2) for detecting the character set
 based on the locale settings.  I suggest we use this (if available) in
 applications like psql and pg_dump by default unless it is overridden by
 the usual mechanisms.  If the character set name obtained this way is not
 recognized by PostgreSQL, we fall back to SQL_ASCII.
 
 Here's a piece of code that shows how this would work:
 
 #include stdio.h
 #include locale.h
 #include langinfo.h
 
 int
 main(int argc, char *argv[])
 {
 setlocale(LC_ALL, );
 printf(%s\n, nl_langinfo(CODESET));
 return 0;
 }
 
 (LC_CTYPE is the governing category for this.)
 
 Comments?

 It isn't enought for all OS. Please, look at glib or libcharset for this 
 problem.

   http://www.haible.de/bruno/packages-libcharset.html

 I use in my project following code that is simplification of
 libcharset (the main function is mp_locale_charset()). 
 Maybe it will help you :-)



/* Determine a canonical name for the current locale's character encoding.
 *
 * mp_locale_charset() inspire with libcharset by:
 *  
 *  Copyright (C) 2000-2002 Free Software Foundation, Inc.
 *  Written by Bruno Haible [EMAIL PROTECTED].  
 *
 * $Id: charset.c,v 1.2 2003/01/24 14:02:01 zakkr Exp $
 */

#include mape.h

#if HAVE_STDDEF_H
# include stddef.h
#endif

#include stdio.h
#if HAVE_STRING_H
# include string.h
#else
# include strings.h
#endif
#if HAVE_STDLIB_H
# include stdlib.h
#endif

#if defined _WIN32 || defined __WIN32__
# undef WIN32   /* avoid warning on mingw32 */
# define WIN32
#endif

#if defined __EMX__
/* Assume EMX program runs on OS/2, even if compiled under DOS.  */
# define OS2
#endif

#if !defined WIN32
# if HAVE_LANGINFO_CODESET
#  include langinfo.h
# else
#  if HAVE_SETLOCALE
#   include locale.h
#  endif
# endif
#elif defined WIN32
# define WIN32_LEAN_AND_MEAN
# include windows.h
#endif
#if defined OS2
# define INCL_DOS
# include os2.h
#endif

typedef struct MpCharsetAlias
{
char*alias,
*name;
} MpCharsetAlias;

extern mpbool mp_locale_charset (char **charset);

/*
 * The libcharset load all from external text file, but it's strange and
 * slow solution, we rather use array(s) compiled into source. In the 
 * good libc this is not needful -- for example in linux.
 * 
 * Please, put to this funtion exotic aliases only. The libc 'iconv' knows
 * a lot of basic aliases (check it first by iconv -l).
 * 
 */
static const char *
mp_charset_aliases (const char *name)
{
MpCharsetAlias  *a;

#if defined WIN32
MpCharsetAlias aliases[] = 
{
{ CP936,  GBK },
{ CP1361, JOHAB },
{ CP20127,ASCII },
{ CP20866,KOI8-R },
{ CP21866,KOI8-RU },
{ CP28591,ISO-8859-1 },
{ CP28592,ISO-8859-2 },
{ CP28593,ISO-8859-3 },
{ CP28594,ISO-8859-4 },
{ CP28595,ISO-8859-5 },
{ CP28596,ISO-8859-6 },
{ CP28597,ISO-8859-7 },
{ CP28598,ISO-8859-8 },
{ CP28599,ISO-8859-9 },
{ CP28605,ISO-8859-15 },
{ NULL, NULL }
};
#elif PORTNAME == aix
MpCharsetAlias aliases[] =
{
{ IBM-850,CP850 },
{ IBM-856,CP856 },
{ IBM-921,ISO-8859-13 },
{ IBM-922,CP922 },
{ IBM-932,CP932 },
{ IBM-943,CP943 },
{ IBM-1046,   CP1046 },
{ IBM-1124,   CP1124 },
{ IBM-1129,   CP1129 },
{ IBM-1252,   CP1252 },
{ IBM-EUCCN,  GB2312 },
{ IBM-EUCJP,  EUC-JP },
{ IBM-EUCKR,  EUC-KR },
{ IBM-EUCTW,  EUC-TW },
{ NULL, NULL }
};
#elif PORTNAME == hpux 
MpCharsetAlias aliases[] =
{
{ ROMAN8, HP-ROMAN8 },
{ ARABIC8,HP-ARABIC8 },
{ GREEK8, HP-GREEK8 },
{ HEBREW8,HP-HEBREW8 },
{ TURKISH8,   HP-TURKISH8 },
{ KANA8,  HP-KANA8 },
{ HP15CN, GB2312 },
{ NULL, NULL }
};
#elif (PORTNAME == irix || PORTNAME == irix5)
MpCharsetAlias aliases[] =
{
{ EUCCN,  GB2312 },
{ NULL, NULL }
};
#elif PORTNAME == osf 
MpCharsetAlias aliases[] =
{
{ KSC5601,CP949 },
{ SDECKANJI,  EUC-JP },
{ TACTIS, TIS-620 },
{ NULL, NULL }
};
#elif (PORTNAME == solaris || PORTNAME == solaris_sparc || POSRTNAME == solaris_i386)
MpCharsetAlias aliases[] =
{
{ 646,