/* nls.c -- skeletal internationalization code. */

/* Copyright (C) 1996 Free Software Foundation, Inc.

   This file is part of the GNU Readline Library, a library for
   reading lines of text with interactive input and history editing.

   The GNU Readline Library is free software; you can redistribute it
   and/or modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; either version 1, or
   (at your option) any later version.

   The GNU Readline Library is distributed in the hope that it will be
   useful, but WITHOUT ANY WARRANTY; without even the implied warranty
   of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   The GNU General Public License is often shipped with GNU software, and
   is generally kept in a file called COPYING or LICENSE.  If you do not
   have a copy of the license, write to the Free Software Foundation,
   675 Mass Ave, Cambridge, MA 02139, USA. */
#define READLINE_LIBRARY

#if defined (HAVE_CONFIG_H)
#  include <config.h>
#endif

#if defined (HAVE_UNISTD_H)
#  include <unistd.h>
#endif /* HAVE_UNISTD_H */

#if defined (HAVE_STDLIB_H)
#  include <stdlib.h>
#else
#  include "ansi_stdlib.h"
#endif /* HAVE_STDLIB_H */

#if defined (HAVE_LOCALE_H)
#  include <locale.h>
#endif

#include <ctype.h>

#include "rldefs.h"

extern int _rl_convert_meta_chars_to_ascii;
extern int _rl_output_meta_chars;
extern int _rl_meta_flag;
    
/* A list of legal values for the LANG or LC_CTYPE environment variables.
   If a locale name in this list is the value for the LC_ALL, LC_CTYPE,
   or LANG environment variable (using the first of those with a value),
   readline eight-bit mode is enabled. */
static char *legal_lang_values[] =
{
 "iso88591",
 "iso88592",
 "iso88593",
 "iso88594",
 "iso88595",
 "iso88596",
 "iso88597",
 "iso88598",
 "iso88599",
 "iso885910",
 "koi8r",   
  0
};

static char *normalize_codeset ();
static char *find_codeset ();

/* Check for LC_ALL, LC_CTYPE, and LANG and use the first with a value
   to decide the defaults for 8-bit character input and output.  Returns
   1 if we set eight-bit mode. */
int
_rl_init_eightbit ()
{
  char *lspec, *t;
  int i;

  lspec = getenv ("LC_ALL");
  if (lspec == 0) lspec = getenv ("LC_CTYPE");
  if (lspec == 0) lspec = getenv ("LANG");
  if (lspec == 0 || (t = normalize_codeset (lspec)) == 0)
    return (0);
  for (i = 0; t && legal_lang_values[i]; i++)
    if (STREQ (t, legal_lang_values[i]))
      {
	_rl_meta_flag = 1;
	_rl_convert_meta_chars_to_ascii = 0;
	_rl_output_meta_chars = 1;
#if defined (HAVE_SETLOCALE)
	setlocale (LC_CTYPE, lspec);
#endif
	break;
      }
  free (t);
  return (legal_lang_values[i] ? 1 : 0);
}

static char *
normalize_codeset (codeset)
     char *codeset;
{
  size_t namelen, i;
  int len, all_digits;
  char *wp, *retval;

  codeset = find_codeset (codeset, &namelen);

  if (codeset == 0)
    return (codeset);

  all_digits = 1;
  for (len = 0, i = 0; i < namelen; i++)
    {
      if (isalnum (codeset[i]))
	{
	  len++;
	  all_digits &= isdigit (codeset[i]);
	}
    }

  retval = (char *)malloc ((all_digits ? 3 : 0) + len + 1);
  if (retval == 0)
    return ((char *)0);

  wp = retval;
  /* Add `iso' to beginning of an all-digit codeset */
  if (all_digits)
    {
      *wp++ = 'i';
      *wp++ = 's';
      *wp++ = 'o';
    }

  for (i = 0; i < namelen; i++)
    if (isalpha (codeset[i]))
      *wp++ = (isupper (codeset[i])) ? tolower (codeset[i]) : codeset[i];
    else if (isdigit (codeset[i]))
      *wp++ = codeset[i];
  *wp = '\0';

  return retval;
}

/* Isolate codeset portion of locale specification. */
static char *
find_codeset (name, lenp)
     char *name;
     size_t *lenp;
{
  char *cp, *language, *result;

  cp = language = name;
  result = (char *)0;

  while (*cp && *cp != '_' && *cp != '@' && *cp != '+' && *cp != ',')
    cp++;

  /* This does not make sense: language has to be specified.  As
     an exception we allow the variable to contain only the codeset
     name.  Perhaps there are funny codeset names.  */
  if (language == cp) 
    {
      *lenp = strlen (language);
      result = language;
    }
  else
    {
      /* Next is the territory. */
      if (*cp == '_')
	do
	  ++cp;
	while (*cp && *cp != '.' && *cp != '@' && *cp != '+' && *cp != ',' && *cp != '_');

      /* Now, finally, is the codeset. */
      result = cp;
      if (*cp == '.')
	do
	  ++cp;
	while (*cp && *cp != '@');

      if (cp - result > 2)
	{
	  result++;
	  *lenp = cp - result;
	}
      else
	{
	  *lenp = strlen (language);
	  result = language;
	}
    }

  return result;
}