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/* Convert UTF-16 string to UTF-8 string.
   Copyright (C) 2002, 2006-2007 Free Software Foundation, Inc.
   Written by Bruno Haible <bruno@clisp.org>, 2002.

   This program 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, or (at your option)
   any later version.

   This program 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 this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
   USA.  */

#include <config.h>

/* Specification.  */
#include "unistr.h"

#define FUNC u16_to_u8
#define SRC_UNIT uint16_t
#define DST_UNIT uint8_t

#include <errno.h>
#include <stdlib.h>
#include <string.h>

DST_UNIT *
FUNC (const SRC_UNIT *s, size_t n, DST_UNIT *resultbuf, size_t *lengthp)
{
  const SRC_UNIT *s_end = s + n;
  /* Output string accumulator.  */
  DST_UNIT *result;
  size_t allocated;
  size_t length;

  if (resultbuf != NULL)
    {
      result = resultbuf;
      allocated = *lengthp;
    }
  else
    {
      result = NULL;
      allocated = 0;
    }
  length = 0;
  /* Invariants:
     result is either == resultbuf or == NULL or malloc-allocated.
     If length > 0, then result != NULL.  */

  while (s < s_end)
    {
      ucs4_t uc;
      int count;

      /* Fetch a Unicode character from the input string.  */
      count = u16_mbtouc (&uc, s, s_end - s);
      if (count < 0)
	{
	  if (!(result == resultbuf || result == NULL))
	    free (result);
	  errno = EILSEQ;
	  return NULL;
	}
      s += count;

      /* Store it in the output string.  */
      count = u8_uctomb (result + length, uc, allocated - length);
      if (count == -1)
	{
	  if (!(result == resultbuf || result == NULL))
	    free (result);
	  errno = EILSEQ;
	  return NULL;
	}
      if (count == -2)
	{
	  DST_UNIT *memory;

	  allocated = (allocated > 0 ? 2 * allocated : 12);
	  if (length + 6 > allocated)
	    allocated = length + 6;
	  if (result == resultbuf || result == NULL)
	    memory = (DST_UNIT *) malloc (allocated * sizeof (DST_UNIT));
	  else
	    memory =
	      (DST_UNIT *) realloc (result, allocated * sizeof (DST_UNIT));

	  if (memory == NULL)
	    {
	      if (!(result == resultbuf || result == NULL))
		free (result);
	      errno = ENOMEM;
	      return NULL;
	    }
	  if (result == resultbuf && length > 0)
	    memcpy ((char *) memory, (char *) result,
		    length * sizeof (DST_UNIT));
	  result = memory;
	  count = u8_uctomb (result + length, uc, allocated - length);
	  if (count < 0)
	    abort ();
	}
      length += count;
    }

  if (length == 0)
    {
      if (result == NULL)
	{
	  /* Return a non-NULL value.  NULL means error.  */
	  result = (DST_UNIT *) malloc (1);
	  if (result == NULL)
	    {
	      errno = ENOMEM;
	      return NULL;
	    }
	}
    }
  else if (result != resultbuf && length < allocated)
    {
      /* Shrink the allocated memory if possible.  */
      DST_UNIT *memory;

      memory = (DST_UNIT *) realloc (result, length * sizeof (DST_UNIT));
      if (memory != NULL)
	result = memory;
    }

  *lengthp = length;
  return result;
}
kc3-lang/gnulib/lib/unistr/u16-to-u8.c

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lib/unistr/u16-to-u8.c
