/* Find matching transformation algorithms and initialize steps.

   Copyright (C) 1997-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 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

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library; if not, see

   <http://www.gnu.org/licenses/>.  */

#include <errno.h>

#include <locale.h>

#include "../locale/localeinfo.h"

#include <stdlib.h>

#include <string.h>

#include <gconv_int.h>

int

__gconv_open (const char *toset, const char *fromset, __gconv_t *handle,

	      int flags)

{

  struct __gconv_step *steps;

  size_t nsteps;

  __gconv_t result = NULL;

  size_t cnt = 0;

  int res;

  int conv_flags = 0;

  const char *errhand;

  const char *ignore;

  bool translit = false;

  /* Find out whether any error handling method is specified.  */

  errhand = strchr (toset, '/');

  if (errhand != NULL)

    errhand = strchr (errhand + 1, '/');

  if (__glibc_likely (errhand != NULL))

    {

      if (*++errhand == '\0')

	errhand = NULL;

      else

	{

	  /* Make copy without the error handling description.  */

	  char *newtoset = (char *) alloca (errhand - toset + 1);

	  char *tok;

	  char *ptr = NULL /* Work around a bogus warning */;

	  newtoset[errhand - toset] = '\0';

	  toset = memcpy (newtoset, toset, errhand - toset);

	  /* Find the appropriate transliteration handlers.  */

	  tok = strdupa (errhand);

	  tok = __strtok_r (tok, ",", &ptr);

	  while (tok != NULL)

	    {

	      if (__strcasecmp_l (tok, "TRANSLIT", _nl_C_locobj_ptr) == 0)

		translit = true;

	      else if (__strcasecmp_l (tok, "IGNORE", _nl_C_locobj_ptr) == 0)

		/* Set the flag to ignore all errors.  */

		conv_flags |= __GCONV_IGNORE_ERRORS;

	      tok = __strtok_r (NULL, ",", &ptr);

	    }

	}

    }

  /* For the source character set we ignore the error handler specification.

     XXX Is this really always the best?  */

  ignore = strchr (fromset, '/');

  if (ignore != NULL && (ignore = strchr (ignore + 1, '/')) != NULL

      && *++ignore != '\0')

    {

      char *newfromset = (char *) alloca (ignore - fromset + 1);

      newfromset[ignore - fromset] = '\0';

      fromset = memcpy (newfromset, fromset, ignore - fromset);

    }

  /* If the string is empty define this to mean the charset of the

     currently selected locale.  */

  if (strcmp (toset, "//") == 0)

    {

      const char *codeset = _NL_CURRENT (LC_CTYPE, CODESET);

      size_t len = strlen (codeset);

      char *dest;

      toset = dest = (char *) alloca (len + 3);

      memcpy (__mempcpy (dest, codeset, len), "//", 3);

    }

  if (strcmp (fromset, "//") == 0)

    {

      const char *codeset = _NL_CURRENT (LC_CTYPE, CODESET);

      size_t len = strlen (codeset);

      char *dest;

      fromset = dest = (char *) alloca (len + 3);

      memcpy (__mempcpy (dest, codeset, len), "//", 3);

    }

  res = __gconv_find_transform (toset, fromset, &steps, &nsteps, flags);

  if (res == __GCONV_OK)

    {

      /* Allocate room for handle.  */

      result = (__gconv_t) malloc (sizeof (struct __gconv_info)

				   + (nsteps

				      * sizeof (struct __gconv_step_data)));

      if (result == NULL)

	res = __GCONV_NOMEM;

      else

	{

	  /* Remember the list of steps.  */

	  result->__steps = steps;

	  result->__nsteps = nsteps;

	  /* Clear the array for the step data.  */

	  memset (result->__data, '\0',

		  nsteps * sizeof (struct __gconv_step_data));

	  /* Call all initialization functions for the transformation

	     step implementations.  */

	  for (cnt = 0; cnt < nsteps; ++cnt)

	    {

	      size_t size;

	      /* Would have to be done if we would not clear the whole

                 array above.  */

#if 0

	      /* Reset the counter.  */

	      result->__data[cnt].__invocation_counter = 0;

	      /* It's a regular use.  */

	      result->__data[cnt].__internal_use = 0;

#endif

	      /* We use the `mbstate_t' member in DATA.  */

	      result->__data[cnt].__statep = &result->__data[cnt].__state;

	      /* The builtin transliteration handling only

		 supports the internal encoding.  */

	      if (translit

		  && __strcasecmp_l (steps[cnt].__from_name,

				     "INTERNAL", _nl_C_locobj_ptr) == 0)

		conv_flags |= __GCONV_TRANSLIT;

	      /* If this is the last step we must not allocate an

		 output buffer.  */

	      if (cnt < nsteps - 1)

		{

		  result->__data[cnt].__flags = conv_flags;

		  /* Allocate the buffer.  */

		  size = (GCONV_NCHAR_GOAL * steps[cnt].__max_needed_to);

		  result->__data[cnt].__outbuf = malloc (size);

		  if (result->__data[cnt].__outbuf == NULL)

		    {

		      res = __GCONV_NOMEM;

		      goto bail;

		    }

		  result->__data[cnt].__outbufend =

		    result->__data[cnt].__outbuf + size;

		}

	      else

		{

		  /* Handle the last entry.  */

		  result->__data[cnt].__flags = conv_flags | __GCONV_IS_LAST;

		  break;

		}

	    }

	}

      if (res != __GCONV_OK)

	{

	  /* Something went wrong.  Free all the resources.  */

	  int serrno;

	bail:

	  serrno = errno;

	  if (result != NULL)

	    {

	      while (cnt-- > 0)

		free (result->__data[cnt].__outbuf);

	      free (result);

	      result = NULL;

	    }

	  __gconv_close_transform (steps, nsteps);

	  __set_errno (serrno);

	}

    }

  *handle = result;

  return res;

}