gconv_trans.c

/* Transliteration using the locale's data.
   Copyright (C) 2000 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 2000.

   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 <dlfcn.h>
#include <stdint.h>

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


int
__gconv_transliterate (struct __gconv_step *step,
		       struct __gconv_step_data *step_data,
		       const unsigned char *inbufstart,
		       const unsigned char **inbufp,
		       const unsigned char *inbufend,
		       unsigned char **outbufstart, size_t *irreversible)
{
  /* Find out about the locale's transliteration.  */
  uint_fast32_t size;
  uint_fast32_t layers;
  uint32_t *from_idx;
  uint32_t *from_tbl;
  uint32_t *to_idx;
  uint32_t *to_tbl;
  uint32_t *winbuf;
  uint32_t *winbufend;
  uint_fast32_t low;
  uint_fast32_t high;
  uint32_t *default_missing;

  /* If there is no transliteration information in the locale don't do
     anything and return the error.  */
  size = _NL_CURRENT_WORD (LC_CTYPE, _NL_CTYPE_TRANSLIT_HASH_SIZE);
  if (size == 0)
    goto no_rules;

  /* Get the rest of the values.  */
  layers = _NL_CURRENT_WORD (LC_CTYPE, _NL_CTYPE_TRANSLIT_HASH_LAYERS);
  from_idx = (uint32_t *) _NL_CURRENT (LC_CTYPE, _NL_CTYPE_TRANSLIT_FROM_IDX);
  from_tbl = (uint32_t *) _NL_CURRENT (LC_CTYPE, _NL_CTYPE_TRANSLIT_FROM_TBL);
  to_idx = (uint32_t *) _NL_CURRENT (LC_CTYPE, _NL_CTYPE_TRANSLIT_TO_IDX);
  to_tbl = (uint32_t *) _NL_CURRENT (LC_CTYPE, _NL_CTYPE_TRANSLIT_TO_TBL);

  /* The input buffer.  There are actually 4-byte values.  */
  winbuf = (uint32_t *) *inbufp;
  winbufend = (uint32_t *) inbufend;

  /* Test whether there is enough input.  */
  if (winbuf + 1 > winbufend)
    return (winbuf == winbufend
	    ? __GCONV_EMPTY_INPUT : __GCONV_INCOMPLETE_INPUT);

  /* The array starting at FROM_IDX contains indeces to the string table
     in FROM_TBL.  The indeces are sorted wrt to the strings.  I.e., we
     are doing binary search.  */
  low = 0;
  high = size;
  while (low < high)
    {
      uint_fast32_t med = (low + high) / 2;
      uint32_t idx;
      int cnt;

      /* Compare the string at this index with the string at the current
	 position in the input buffer.  */
      idx = from_idx[med];
      cnt = 0;
      do
	{
	  if (from_tbl[idx + cnt] != winbuf[cnt])
	    /* Does not match.  */
	    break;
	  ++cnt;
	}
      while (from_tbl[idx + cnt] != L'\0' && winbuf + cnt < winbufend);

      if (cnt > 0 && from_tbl[idx + cnt] == L'\0')
	{
	  /* Found a matching input sequence.  Now try to convert the
	     possible replacements.  */
	  uint32_t idx2 = to_idx[med];

	  do
	    {
	      /* Determine length of replacement.  */
	      uint_fast32_t len = 0;
	      int res;
	      const unsigned char *toinptr;

	      while (to_tbl[idx2 + len] != L'\0')
		++len;

	      /* Try this input text.  */
	      toinptr = (const unsigned char *) &to_tbl[idx2];
	      res = DL_CALL_FCT (step->__fct,
				 (step, step_data, &toinptr,
				  (const unsigned char *) &to_tbl[idx2 + len],
				  (unsigned char **) outbufstart,
				  irreversible, 0, 0));
	      if (res != __GCONV_ILLEGAL_INPUT)
		{
		  /* If the conversion succeeds we have to increment the
		     input buffer.  */
		  if (res == __GCONV_EMPTY_INPUT)
		    {
		      *inbufp += cnt * sizeof (uint32_t);
		      ++*irreversible;
		    }

		  return res;
		}

	      /* Next replacement.  */
	      idx2 += len + 1;
	    }
	  while (to_tbl[idx2] != L'\0');

	  /* Nothing found, continue searching.  */
	}

      if (winbuf + cnt >= winbufend || from_tbl[idx + cnt] < winbuf[cnt])
	low = idx;
      else
	high = idx;
    }

  /* One last chance: use the default replacement.  */
 no_rules:
  default_missing = (uint32_t *)
    _NL_CURRENT (LC_CTYPE, _NL_CTYPE_TRANSLIT_DEFAULT_MISSING);
  if (default_missing[0] != L'\0')
    {
      const unsigned char *toinptr = (const unsigned char *) default_missing;
      uint32_t len = _NL_CURRENT_WORD (LC_CTYPE,
				       _NL_CTYPE_TRANSLIT_DEFAULT_MISSING_LEN);
      int res;

      res = DL_CALL_FCT (step->__fct,
			 (step, step_data, &toinptr,
			  (const unsigned char *) (default_missing + len),
			  (unsigned char **) outbufstart,
			  irreversible, 0, 0));

      if (res != __GCONV_ILLEGAL_INPUT)
	{
	  /* If the conversion succeeds we have to increment the
	     input buffer.  */
	  if (res == __GCONV_EMPTY_INPUT)
	    {
	      /* We consuming one character.  */
	      ++*inbufp;
	      ++*irreversible;
	    }

	  return res;
	}
    }

  /* Haven't found a match.  */
  return __GCONV_ILLEGAL_INPUT;
}