/* Copyright (C) 1998 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <langinfo.h>
#include <limits.h>

#include <wcsmbsload.h>
#include <bits/libc-lock.h>
#include <iconv/gconv_int.h>


/* Last loaded locale for LC_CTYPE.  We initialize for the C locale
   which is enabled at startup.  */
extern const struct locale_data _nl_C_LC_CTYPE;
const struct locale_data *__wcsmbs_last_locale = &_nl_C_LC_CTYPE;


/* These are the descriptions for the default conversion functions.  */
static struct gconv_step to_wc =
{
  shlib_handle: NULL,
  modname: NULL,
  counter: INT_MAX,
  from_name: "ANSI_X3.4-1968//",
  to_name: "INTERNAL",
  fct: __gconv_transform_ascii_internal,
  init_fct: NULL,
  end_fct: NULL,
  data: NULL
};

static struct gconv_step to_mb =
{
  shlib_handle: NULL,
  modname: NULL,
  counter: INT_MAX,
  from_name: "INTERNAL",
  to_name: "ANSI_X3.4-1968//",
  fct: __gconv_transform_internal_ascii,
  init_fct: NULL,
  end_fct: NULL,
  data: NULL
};


/* For the default locale we only have to handle ANSI_X3.4-1968.  */
struct gconv_fcts __wcsmbs_gconv_fcts =
{
  towc: &to_wc,
  tomb: &to_mb
};


static inline struct gconv_step *
getfct (const char *to, const char *from)
{
  size_t nsteps;
  struct gconv_step *result;

  if (__gconv_find_transform (to, from, &result, &nsteps) != GCONV_OK)
    /* Loading the conversion step is not possible.  */
    return NULL;

  /* We must only have one step in this conversion.  */
  if (nsteps != 1)
    return NULL;

  return result;
}


/* Load conversion functions for the currently selected locale.  */
void
__wcsmbs_load_conv (const struct locale_data *new_category)
{
  /* We must modify global data.  */
  __libc_lock_define_initialized (static, lock)

  /* Acquire the lock.  */
  __libc_lock_lock (lock);

  /* We should repest the test since while we waited some other thread
     might have run this function.  */
  if (__wcsmbs_last_locale != new_category)
    {
      if (new_category->name == _nl_C_name)	/* Yes, pointer comparison.  */
	{
	failed:
	  __wcsmbs_gconv_fcts.towc = &to_wc;
	  __wcsmbs_gconv_fcts.tomb = &to_mb;
	}
      else
	{
	  /* We must find the real functions.  */
	  const char *charset_name;

	  /* Get name of charset of the locale.  */
	  charset_name = new_category->values[_NL_ITEM_INDEX(CODESET)].string;

	  __wcsmbs_gconv_fcts.tomb = getfct (charset_name, "INTERNAL");
	  __wcsmbs_gconv_fcts.towc = getfct ("INTERNAL", charset_name);

	  /* If any of the conversion functions is not available we don't
	     use any since this would mean we cannot convert back and
	     forth.*/
	  if (__wcsmbs_gconv_fcts.towc == NULL
	      || __wcsmbs_gconv_fcts.tomb == NULL)
	    goto failed;
	}

      /* Set last-used variable for current locale.  */
      __wcsmbs_last_locale = new_category;
    }

  __libc_lock_unlock (lock);
}